STEM Today

SPACE FOOD AND NUTRITION

STEM TODAY October 2016, No.13

SPACE FOOD AND NUTRITION

STEM TODAY October 2016 , No.13

CONTENTS SPACE FOOD AND NUTRITION Food­01: We need to determine how processing and storage affect the nutritional content of the food system

Editorial Editor: Mr. Abhishek Kumar Sinha Editor / Technical Advisor: Mr. Martin Cabaniss

STEM Today, October 2016, No.13

Biography Vickie L. Kloeris has a bachelor’s of science in microbiology and a master’s degree in food science and technology, both from Texas A&M University.

Kloeris came to work at Johnson Space Center as a food scientist in 1985.

From 1985 through 1989, she was employed by NASA contractors in positions related to space food processing and provisioning. Since 1989, Ms. Kloeris has been employed by NASA as the Subsystem Manager for the Shuttle Food System. In January of 2000, Ms. Kloeris assumed the additional duties of managing the Space Station food system and the Space Food Systems Laboratory.

In her current position as Manager of Flight Food Systems she is responsible for the operation and continuing development of the Shuttle and International Space Station food systems. Kloeris is an active member of the Institute of Food Technologists and currently serves on the Advisory Council for the Institute of Food Science and Engineering at Texas A&M University.

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Biography Page Vickie L. Kloeris Manager,Flight Food Systems , NASA. Image Credit: NASA

Cover Page Space Food Laboratory Gallery JSC2003E63871 – Image taken in the Food Tasting lab in bldg 17: Manager of the Food Tasting lab Vickie L. Kloeris poses with bags of Space Station food on a tray.

Image Credit: NASA

Back Cover NASA’s MAVEN Mission Gives Unprecedented Ultraviolet View of Mars MAVEN’s Imaging UltraViolet Spectrograph obtained images of rapid cloud formation on Mars on July 9-10, 2016. The ultraviolet colors of the planet have been rendered in false color, to show what we would see with ultraviolet-sensitive eyes. Mars’ tallest volcano, Olympus Mons, appears as a prominent dark region near the top of the image, with a small white cloud at the summit that grows during the day. Three more volcanoes appear in a diagonal row, with their cloud cover (white areas near center) merging to span up to a thousand miles by the end of the day.

Image Credit: NASA/MAVEN/University of Colorado

STEM Today , October 2016

Editorial Dear Reader

STEM Today, October 2016, No.13

All young people should be prepared to think deeply and to think well so that they have the chance to become the innovators, educators, researchers, and leaders who can solve the most pressing challenges facing our world, both today and tomorrow. But, right now, not enough of our youth have access to quality STEM learning opportunities and too few students see these disciplines as springboards for their careers.

According to Marillyn Hewson, "Our children - the elementary, middle and high school students of today - make up a generation that will change our universe forever. This is the generation that will walk on Mars, explore deep space and unlock mysteries that we can’t yet imagine". "They won’t get there alone. It is our job to prepare, inspire and equip them to build the future - and that’s exactly what Generation Beyond is designed to do."

STEM Today will inspire and educate people about Spaceflight and effects of Spaceflight on Astronauts.

Editor Mr. Abhishek Kumar Sinha

Editorial Dear Reader The Science, Technology, Engineering and Math (STEM) program is designed to inspire the next generation of innovators, explorers, inventors and pioneers to pursue STEM careers.

According to President Barack Obama, "[Science] is more than a school subject, or the periodic table, or the properties of waves. It is an approach to the world, a critical way to understand and explore and engage with the world, and then have the capacity to change that world..."

STEM Today addresses the inadequate number of teachers skilled to educate in Human Spaceflight. It will prepare , inspire and educate teachers about Spaceflight. STEM Today will focus on NASA’S Human Research Roadmap. It will research on long duration spaceflight and put together latest research in Human Spaceflight in its monthly newsletter.

Editor / Technical Advisor Mr. Martin Cabaniss

STEM Today, October 2016, No.13

SPACE FOOD AND NUTRITION Gap in NASA's Human Research Roadmap

Food-01: We need to determine how processing and storage a ect the nutritional content of the food system: The kinetics of vitamin losses through processing and storage of the space food items and the amount of remaining nutrition at the end of ve years is unknown. The e ect of ingredient interactions and food matrices on nutrient stability in the food system is also unknown.

Special Edition on Space Food and Nutrition

Food System for Long-Duration Missions Several types of food and beverage packaging have been used in NASA space programs, but the storage environment has been virtually constant. With the exception of Skylab, no refrigerator or freezer dedicated to food storage has flown on any U.S. space vehicle. Consequently, the food is provided in a shelf stable form for storage at ambient temperature. To achieve stability, the food undergoes inactivation of the microorganisms during ground processing. Although processing the packaged foods to commercial sterility provides a safe food system, this level of processing can reduce the quality of the food, including nutritional content and acceptability.

The different forms in which food is provided include the following[Food For Space Flight, NASA & Cooper et.al.]: • Thermostabilized-Thermostabilized foods are heat processed to destroy deleterious microorganisms and enzymes. Individual servings of thermostabilized foods are commercially available in aluminum or bimetallic cans, plastic cups, or in flexible retort pouches. Most of the fruits, and fish such as tuna and salmon, are thermostabilized in cans. The cans open with easy-open, full-panel, pullout lids. Puddings are packaged in plastic cups. Most of the entrees are packaged in flexible retort pouches. This includes products such as beef tips with mushrooms, tomatoes and eggplant, chicken ala king, and ham. After the pouches are heated, they are cut open with scissors. The food is eaten directly from the containers with conventional eating utensils.

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• Irradiated-irradiation is not typically used to process foods to commercial sterility. However, NASA has received special dispensation from the Food and Drug Administration (FDA) to prepare 9 irradiated meat items to commercial sterility (FDA 2009).

• Rehydratable-Rehydratable items include both foods and beverages. One way weight can be conserved during launch is to remove water in the food system. During the flight, water is added back to the food just before it is eaten. The Shuttle orbiter fuel cells, which produce electricity by combining hydrogen and oxygen, provide ample water for rehydrating foods as well as drinking and a host of other uses.

Foods packaged in rehydratable containers include soups like chicken consomme and cream of mushroom, casseroles like macaroni and cheese and chicken and rice, appetizers like shrimp cocktail, and breakfast foods like scrambled eggs and cereals. Breakfast cereals are prepared by packaging the cereal in a rehydratable package with nonfat dry milk and sugar, if needed. Water is added to the package just before the cereal is eaten.

• Natural form-Foods such as nuts, granola bars, and cookies are classified as natural form foods. They are ready to eat, packaged in flexible pouches, and require no further processing for consumption in flight.

Both natural form and intermediate moisture foods are packaged in clear, flexible pouches that are cut open with scissors.

• Extended shelf life bread products-items, such as scones, waffles, tortillas, and dinner rolls, can be formulated and packaged to give them a shelf life of up to 18 months. Like the natural form foods, breads add to menu variety and address crewmembers’ desire for familiarity.

• Fresh food-foods such as fresh fruits and vegetables, which have a short shelf life, are provided on a limited basis, more for psychological support than as a means to meet dietary requirements.

• Beverages-the beverages currently used on the International Space Station (ISS) and the Space Shuttle are either freeze-dried beverage mixes (such as coffee or tea) or flavored drinks (such as lemonade or orange drink). The drink mixes are weighed and then vacuum sealed inside a beverage pouch. In the case of coffee or tea, sugar or powdered cream can be added to the pouch before sealing. Empty beverage pouches are also provided for drinking water.

The Mars missions, in particular, will require development of technologies to enable the crew to be selfsufficient and less dependent on resupply missions. One proposed mission to Mars designates use of the prepackaged foods, similar to those used on the ISS, for transit but may also include positioning food on Mars before the crew arrives. Under this scenario, prepositioned food may be 3- to 5-years old at the time of consumption.

Achieving a 5-years shelf life to make this mission scenario feasible is an ambitious goal given that the current prepackaged foods have a stated shelf life of 18 months. The determining factors for shelf life-safety, nutrition, and sensory acceptability-must be optimized to maximize the shelf life within the mission scenario. These missions will also require that more attention be paid to utilization of resources including mass, volume, power, crew time, and water.

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Special Edition on Space Food and Nutrition

The following 5 items needs for the space food system to successfully supply long exploration missions: • Nutrient-dense, shelf stable foods that meet overall sensory acceptability metrics; • shelf stable menu items with at least a 5-years shelf life; • partial gravity cooking processes with minimization of microbial risk; • sustained vitamin delivery in shelf stable foods; • a packaging material that meets high-barrier, low-mass, and process-compatibility constraints.

Nutrient-dense foods NASA concerns about mission resource utilization focus on the mass of all crew consumables, but particularly on food provisions because food is such a large percentage of upmass . The mass of the food system depends on the form of foods on the menu and the quantity of food required to meet the crew’s caloric requirements. Historically, the food system began with product design focused on mass and volume restrictions but transitioned to focus on palatability after crew intake became a concern for flight doctors.

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Packaged Food Mass Reduction Trade Study Future long duration manned space flights beyond low earth orbit will require the food system to remain safe, acceptable and nutritious while efficiently balancing appropriate vehicle resources such as mass, volume, power, water, and crew time. Often this presents a challenge since maintaining the quality of the food system can result in a higher mass and volume.

The objective of this project was to determine how the mass and volume of the packaged food can be reduced while maintaining caloric and hydration requirements. The Orion vehicle is significantly smaller than the Shuttle vehicle and the International Space Station (ISS) and the mass and volume available for food is limited. Therefore the food team has been challenged to reduce the mass of the packaged food from 4 pounds per person per day to 2.5 pounds per person per day.

Overall, this study found that significant reductions in food system mass are possible with further menu development. With the reduction of moisture and increase in calories from fat, the system mass decreased by 321 gram per crewmember per day, or 22%. With the substitution of standard menu items with meal replacement bars, the mass can be reduced by 240 grams, or 17%, and is limited to one bar per crewmember per day. If both approaches were combined, the mass of the food system can be reduced by as much as 529 grams, or 36%. Combining the meal replacement option with the reducing the moisture and increasing fat would have a net reduction from 1.81 kg to 1.28 kg per crewmember per day which approaches the overall reduction goal of 1.18 kg [Packaged Food Mass Reduction Trade Study (Mass_Reduction),LSDA,NASA].

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The Gemini Food System, bite-size cubes of meat, fruit, dessert, and bread products were engineered to deliver 21.3 J/g, and the complete food system offered 12100 J, or about 2890 cal, in 0.73 kg of packaged food . However, the in-flight acceptability of cubes quickly waned and many cubes were returned uneaten. The introduction of more rehydratable foods increased mass; the mass of the Apollo 7 food system was 0.82 kg of food per person per day. The Apollo 8 crew, in 1968, preferred the newly added thermostabilized foods, referred to as "wetpack foods." By the Apollo 14 mission, the mass of the food averaged 1.1 kg per person per day. The crew preference for the thermostabilized product justified the weight increase. Even with the added "wetpack foods," the Apollo food system still contained a significant number of freeze-dried foods, since water from the fuel cells was available for food rehydration.

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Special Edition on Space Food and Nutrition

Current ISS and Shuttle crewmembers receive about 1.8 kg of food plus packaging per person per day. A higher percentage of this food is thermostabilized than on the Apollo missions because the thermostabilized food is still generally preferred in taste tests to freeze-dried items by crew members. Since the ISS utilizes solar panels for a power source and not fuel cells that produce water as a by-product, there is no mass advantage to using freezedried foods. Water is now transported to the ISS for rehydration. Furthermore, contributing to the mass increase is an increase in the required caloric delivery. The required calories as stated in the mission guidelines is based on the actual caloric needs of the crewmember, which are based on body weight and height. The result is an average caloric requirement of 3000 kcal (12550 kJ) as opposed to the 2500 kcal (10460 kJ) provided to the Apollo crew. In light of these mass challenges, NASA is considering various avenues of food mass reduction while still providing the crew with adequate calories and an acceptable diet.

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U.S. Army helps to meet nutritional needs of Mars astronauts

Researchers in the Combat Feeding Directorate, or CFD, at the Natick Soldier Research, Development and Engineering Center, or NSRDEC, are working on two projects for NASA to help meet the nutritional needs of astronauts at a space station and astronauts traveling to Mars. NASA contacted CFD researchers for their expertise and provided a grant for a vitamin stabilization project to help ensure the nutritional needs of astronauts are met during potential missions to Mars. In a separate project, CFD is also working to improve and reduce the weight and volume of a breakfast meal replacement bar, originally developed by NASA, which would also be

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Special Edition on Space Food and Nutrition used during Mars missions and at a space station. "The work we have done on the vitamin stabilization project then generated NASA’s interest in us working on a meal replacement bar for the breakfast meal," said Michelle Richardson, a senior food technologist at CFD. CFD is uniquely qualified to develop and improve rations for NASA due to its extensive work on military rations, Richardson said.

"The work we do in CFD involves meeting the long storage requirements combined with the nutritional demands for Army rations," said Ann Barrett, a CFD chemical engineer.

"The astronaut and the warfighter are both in austere environments, and they both need to be sustained," Richardson said. "They both need food that has to last for several years."

STEM Today, October 2016, No.13

"They both have stressful as well as physically and cognitively challenging jobs," Barrett said. "So there are a lot of congruencies between CFD and NASA in terms of the objectives for the foods."

VITAMIN STABLIZATION The mission to Mars provides many challenges in vitamin stabilization. "You can make food that is stable, but vitamins are biological materials that degrade over time," Barrett said. "Especially if there is cosmic radiation; then they are even more susceptible to degradation. Cosmic radiation can damage vitamins and create more of a need for antioxidant vitamins for the astronauts. This could result in malnutrition." The vitamins need to remain effective and intact during the astronauts’ time on Mars, and they also need to remain stable during travel to and from Mars. "NASA is also interested in stockpiling food there for subsequent missions, which is why they want a five-year shelf life," Barrett said. CFD has developed a blueberry granola bar and a chocolate hazelnut drink mix to meet these requirements. "We are looking at different chemical environments in the food to possibly help the vitamins last longer," Barrett said. "So for each item - the bar and the drink - we have a low-fat version and a higher fat version. The vitamins that NASA is interested in are A, B1 [Thiamine], B9 [Folic Acid], Vitamin C and Vitamin E. "The vitamins are encapsulated. We are also looking at the fat level. We have a lipid-based encapsulate and a starch-based encapsulate." Both the starch-coated vitamins and the lipid-coated vitamins were placed into low- and high-fat versions of the bar and the drink to see which combination results in the best vitamin preservation. "We did preliminary testing and decided which versions were to be used in a five-year storage study," Barrett said. "We settled on the fat-encapsulated vitamins to be placed in the lower fat foods. And the starchencapsulated vitamins were placed in the higher fat foods."

As part of the effort for NASA, Danielle Froio, a materials engineer at CFD, is also investigating the effects of processing techniques and packaging materials on vitamin stability in the selected low- and high-fat foods.

RAISING THE BREAKFAST BAR ON NUTRITION WHILE REDUCING THE VOLUME CFD is working on a breakfast bar as a meal replacement to be used at a space station and possibly during a Mars mission. NASA developed the bar, and Natick is working on refining it. "NASA is interested in a 10-percent weight reduction, and they achieved that through the bar, but they didn’t have the capability to refine it," Froio said. "Natick is investigating two ways to reduce weight and volume. One is a conventional compression method, which uses high pressure. "The other is a novel technology called sonic agglomeration that basically uses sonic waves to compress the bar and make the ingredients stick together. So, we are looking at those two technologies." The resulting breakfast bar will be lighter weight and take up less volume, which is critical in space travel.

The bars meet all the nutrient requirements for space flight and will be available in three flavors - barbecue nut, jalapeno nut and banana nut. "The bar also needs to last for five years and taste good," Richardson said.

"NASA is going to do shelf-life testing, sensory testing and nutrient testing. They are also going to do human exploration research analogs. "An analog is actually an environment that mimics space. The bars will be tested by people in that simulated environment."

MISSION CRITICAL NUTRITION Proper nutrition and vitamin stability are critical to the success of any space mission. "Vitamins help with immunity," Richardson said. "It’s also important that the astronauts don’t lose muscle mass and bone density, which they are more prone to in a gravity-free environment." "Antioxidants also help with neural function," Barrett said. "Vitamins do a lot for the body," Richardson said. "So, without them on a five-year space mission, they would not be able to do their job and they would not be healthy." "We’ve done other things for NASA in the past," Barrett said. "It’s a long collaboration. I think the possibility of exploring Mars is a very exciting thing."

"It’s great that we can assist with the sustainment of that mission," Richardson said. "If they are not properly nourished, that is going to have a huge impact."

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Special Edition on Space Food and Nutrition The work by Stoklosa highlighted an opportunity for menu improvement, as did a concurrent AFT menu analysis exercise. The aim of the exercise was to qualitatively determine the efficiency of the current space food system in delivering nutrients and calories to the crew. Based upon the naturally nutrient rich (NNR) score as presented by Drewnowski, a simple (NNR) score was calculated as the average of the percentage daily values (DVs) for 16 nutrients given 2000 kcal, or 8368 kJ, of each particular food item (2005): P NNR= %DV2000kcal /16

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The 16 nutrients were protein, calcium, iron, vitamin A, vitamin C, thiamin, riboflavin, vitamin B-12, folate, vitamin D, vitamin E, magnesium, potassium, zinc, fiber, and pantothenic acid. The NNR score presented by Drewnowski incorporates monounsaturated fat but those values were not available for the space foods. Magnesium is considered a significant nutrient by the National Cancer Institute and is included within calculations of the calories-for-nutrient (CFN) nutrient density score; thus, it was chosen to replace monounsaturated fat in the calculations. Rather than 14 nutrients, the more recent recommendation to consider 16 nutrients was followed.

Finally, to prevent severe skewing of the score by any single nutrient, very high percentage DVs were truncated at 2000%. The results of the exercise are depicted graphically in Figure 1.

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In this analysis, the energy-dilute foods, such as beverages and vegetables, have the highest NNR score.

However, the energy density of these categories is quite low. Substantially more beverage and vegetable mass would be required if these categories were heavily used to provision the crew. Hence, low energy density foods conflict with the goal to minimize required upmass. In contrast, nuts are the most efficient offering currently, having relatively high energy, and significant nutrients in a compact food matrix. Significant white space exists for higher density, more nutritious foods in the space food system. Directional shifts of the food supply to the upper left portion of Figure 1 would ultimately allow a smaller mass of food to meet the required macronutrient and micronutrient needs of the crew. Care must be taken during any future menu planning to ensure that nutritionally void items are not selected solely for their the caloric contribution and that the bioavailability of the nutrients within the foods are considered.

Extended shelf life products Commercial shelf stable food products are generally accepted as having sufficient shelf life, if the product is still consumer-accepted 1 year after manufacturing. NASA assigns an 18 to 24- months shelf life to most space food provisions, but even this span is inadequate for future deep space missions. A main consideration in the quality

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Special Edition on Space Food and Nutrition of the food is how the food is perceived by the crew. The complexity of food acceptability prevents definitive quantitative assessment. Currently, flight foods are evaluated using sensory analysis for acceptability on the ground by a panel of 30 or more consumers. The products are rated on the basis of appearance, flavor, texture, and aroma using a 9-point Hedonic Scale.

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Hedonic Scale

However, product acceptability can also be affected by factors such as product age, storage conditions, and the environment where the food is consumed. Menu variety and usability of the food system also contribute to food acceptability. A large variety of food items are recommended to provide the crew with choices and to avoid menu fatigue. If the food is difficult to prepare or eat, then the overall acceptability of the food is reduced. Finally, food acceptability can be affected by the social context and timing of meals. Food and meal times offer crews significant psychological-social benefit, such as reducing the stress and boredom of prolonged space missions or promoting unity by having dinner together.

Even if the food is acceptable to the crew on day one of the mission, the acceptability is not guaranteed to the end of the 5th year, particularly because the food quality degrades. A shelf life study conducted at Johnson Space Center (JSC) from 2003 to 2008 highlighted the quality changes of the thermostabilized space foods over a 3-year period.

The shelf life study began with 13 thermostabilized items stored at 4.4 ◦ C (control), 22 ◦ C (storage temperature of actual flight food), and 35 ◦ C (accelerated temperature) and 50% relative humidity. The shelf life tests were terminated at the point when the product became unacceptable or at 3 year. The study was conducted on an assortment of products (vegetable sides and starch dishes, fruits, desserts, meats, and other entr´ ees) that were chosen to be representative of the entire inventory of thermostabilized food products. Of these, meat products and other entr´ ees were projected to maintain product quality the longest, over 3 year, without refrigeration.

Fruit products and dessert products followed, as they were projected to maintain their quality from 1.5 to 5 year without refrigeration. Starches and vegetable side dishes should maintain their quality from 1 to 4 year without refrigeration. Egg products did not respond adequately to the thermostabilization process and were found unsuitable immediately after production.

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Stability of foods in spaceflight

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Shelf life endpoints determined for the 13 representative products are summarized in Table 4. Of these, 4 endpoints (Sugar Snap Peas, Broccoli Souffl´ e, Vegetable Omelet, and Rhubarb Applesauce) were observed during the 36 months analysis; the shelf life values of the remaining 9 items were determined by extrapolation.

Representative products were found acceptable to panelists immediately after production (average panelist acceptance >6.0), with the exception of one vegetable product (Sugar Snap Peas), and both egg products (Vegetable Omelet and Broccoli Souffl´ e). Panelists cited tartness, bitterness, and an unacceptable aftertaste as the reasons for the low acceptability of Sugar Snap Peas after production. These offflavors were attributed to the increase in organic acid content typically present in canned green vegetables . Incorporation of a preliminary blanching step and inclusion of a brine packing solution are conventional means to avoid this off-flavor development. While the blanching of the snap pea ingredients may prove beneficial, the inclusion of a brine solution is not typically appropriate for NASA applications. Pouched vegetables in brine can prove awkward and untidy in microgravity, and also contribute significant nonedible mass, volume, and wet waste to the total food system.

Formulation of a sauce component that might simulate the beneficial effects of the brine could be considered for NASA applications to improve initial acceptability and ultimately extend the shelf life of this vegetable product.

Although retort processed egg products are not currently offered in the NASA food system, 2 candidate egg products were developed for consideration in this study. The Broccoli Souffl´ e and Vegetable Omelet products were proposed as a means to offer additional menu variety to crew in extended duration missions. Texture was anticipated to be an issue for these products, as the high heat applied the retort process would allow extensive aggregation of egg proteins . Therefore, considerable effort was made in formulating these products to include egg components at a low level and prevent formation of unacceptable texture. Liquid egg product was included in these formulations at 63% w/w (Vegetable Omelet) and 22.5% w/w (Broccoli Souffl´ e). Despite this effort, the heat treatment applied in the retort process was found to render quality of both products unacceptable to all panelists. Although instrumental analysis of these products continued at scheduled intervals, sensory evaluation was terminated after initial analysis.

In addition to texture, unacceptable appearance and odor of egg products were cited by panelists as reasons for failure at 0 month. The unacceptable odor was likely due to formation of sulfurous gases produced during

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STEM Today, October 2016, No.13

cooking of eggs, and subsequent containment of that gas within the retort pouch. The observed, greenish gray color is likely due to the formation of ferrous sulfide that is often observed with extended heating of liquid eggs at high temperatures . Odor could be curbed by decreasing the egg product fraction of the formulation, and appearance may be improved either by acidifying the formulations with salts or through the addition of various chelating agents. Increased springiness and cohesiveness in egg white gel networks have been observed previously as a function of the heating time and temperature . The phenomenon has been attributed to the denaturation of egg albumin proteins with the continued application of heat, and reassembly into an extensive fiber-like network .

Although increased cohesiveness was not indicated by panelist comments on the representative egg products studied, unacceptable hardness, springiness, and rubbery quality were observed. Instrumental texture analysis of these products was carried out for the duration of the storage analysis and showed that hardness of Broccoli Souffl´ e decreased gradually over time (P <0.05). No such decline was observed for Vegetable Omelet, presumably because of its higher protein content. Even with reformulation and in spite of texture softening over time, retorted egg products are not likely to be acceptable for extended duration missions. Emerging processing technologies (microwave/radio frequency and pressure-assisted sterilization) should be considered for this purpose, as they appear to provide acceptability and storage stability that are more appropriate to NASA’s needs.

Overall, changes to the color and flavor of representative products over time were found to have the greatest impact on product quality. For the most part, these changes were slowed significantly with product storage at low temperatures. Changes to product texture and nutritive value during storage were also observed for several of the representative products. Critical color limits observed in representative products over time are summarized in Table 5.

Significant color loss was generally limited to fruits, vegetables, and products containing high proportions of dairy ingredients. Analytical color differences were generally supported by panelist ratings of product appearance, as well as by general panelist comments on product color intensity. Color changes previously reported in long-term storage of canned goods have been defined in terms of color fading in green vegetable products, high carotenoid products, and uncured meats; and color darkening in bakery products, starch products, fruits, and cured meats. Although both fading and darkening were observed in the present study, the latter was the most significant color change influencing product quality. The most substantial declines in color were observed for fruit and vegetable products. On average, the critical color limits of fruit and vegetable products represented a decline of 20% in the value of initial color parameters.

Generally, observation of color fading was limited and had minimal bearing on sensory acceptance of most products. The most substantial fading of color was observed in green color of Sugar Snap Peas, where the Hunter a-value had increased from 1.75 to 2.92 after 20 mo of storage at 72 ◦ F. However, decreases in the Hunter L-value during this time, indicating darkening of the product, were found to have a greater effect on overall product quality.

Additionally, some color fading was measured in the Grilled Pork Chop product, but was not found to have a significant effect on the overall panelist acceptability over time. Color fading in Grilled Pork Chop was characterized in terms of a hue shift from orange to yellow-green. This shift appeared to coincide with decreased reporting by panelists that the product appeared red or pink over storage. The shift was not significant for the product stored at the low temperature (40 ◦ F) conditions. Color darkening was found to have a greater effect than color fading on acceptability of Apricot Cobbler and Carrot Coins products. Although instrumental assessment showed gradual change of all color parameters over time for ambient and high temperature storage of these products, panelist perception of color change was limited to discernment of relative product darkness. The lack of significance of color fading in these products is likely due to their formulations: Carrot Coins contains butter at 1.61% w/w; Apricot Cobbler contains pie crust and sugar at 8.37% and 21.22%, respectively. Both of these products contain reasonable levels of reactive browning precursors, which would therefore account for their darkening over time.

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Special Edition on Space Food and Nutrition Color changes in the Bread Pudding and Tuna Noodle Casserole products were characterized only by product darkening. The critical limits of color decline in these products were more moderate than in fruits and vegetables. Color darkening in Bread Pudding represented a decrease in 12.4% of initial parameter value. It was accompanied by the generation of Maillard-type flavors that were found desirable by panelists until approximately 16 mo of storage at 95 ◦ F. Darkening of Tuna Noodle Casserole occurred gradually throughout storage at ambient and high temperatures, and only represented 8.4% reduction in initial parameter value. These gradual changes were likely the result of nonenzymatic browning reactions, as they occurred most considerably at high temperatures, were accompanied by product darkening, and because the casserole sauce contains dairy and other browning precursors.

However, although the color changes were minor, they were still reflected in panelist ratings of appearance for this product. This was likely due to simultaneous progression of other quality changes that affect appearance, such as moisture migration between sauce and noodle components.

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Darkening of Rhubarb Apple sauce was observed over time at ambient and high temperature storage conditions, while those samples in low temperature storage remained almost unchanged, even after 36 months of storage (P < 0.05). Color change was assumed in large part to be the result of nonenzymatic browning reactions, as it was characterized largely by a decrease in Hunter L-values, was accompanied by a flavor change, and was most pronounced for those products stored at high temperatures. Similar characteristics were observed for the darkening of Roasted Vegetables, but the color aspects were overcome by off-flavor development, presumably because of the relative mildness of the initial product flavor.

Flavor loss was observed in terms of loss of characteristic product flavors and formation of unacceptable flavor, with the latter contributing most significantly to overall acceptability. For most products, flavor change was accompanied by a change in color, which was often observed before panelist perception of flavor differences.

For those products found acceptable at baseline, flavor did not appear to drive overall sensory acceptability until after a minimum of 16 months of storage at ambient conditions. Panelist acceptability of the flavor of all representative vegetable products (Carrot Coins, Three Bean Salad, Roasted Vegetables, Sugar Snap Peas) was found to decline over time, especially at ambient and high temperatures. Similarly, a decreased acceptability of aroma and after tastes were observed in vegetable products stored at high temperatures over time (P <0.05).

As these changes tended to coincide with product darkening, and because of the nature of the products, flavor changes in these vegetable products were assumed to be resultant from Maillard browning reactions.

Maillard reactions were also implicated in the flavor and color change observed in the Bread Pudding representative dessert product. Association of color and flavor changes has previously been observed in a canned fruit cake product by Cecil and Woodruff. Their research noted increasing perception of "bitter" and "burned flavor" with darkening of color. As these changes accompanied by hydrolysis of 50% of the product disaccharides, the study attributed them to nonenzymatic or Maillard browning reactions. NASA dessert products are formulated with adequate dairy, egg, and sugar ingredients to allow formation of characteristic flavors and colors in dessert products by Maillard reactions during processing. At ambient and high temperatures, however, the reactions were allowed to proceed throughout storage to a point where they began to impart negative effects on product quality. This was observed after only 16 months of storage at 95 ◦ F. Sensory analysis suggested that browning reactions in the retort processed dessert can be correlated with increased panelist preference to this point. After this point, however, color quality appears to become unacceptable, and flavor intermediates too overbearing. As most dessert products are formulated similarly and are potentially subject to these reactions, they should conceivably benefit from a moderate amount (<16 months) of high temperature storage.

However, the specific storage conditions should be optimized on a product specific basis to minimize disadvantageous effects and maximize product quality. Although not affecting quality over time, sensory panelists also noted an off-flavor in the Grilled Pork Chops meat entr´ ee, shortly after production. The panelists consistently mentioned that they perceived a fish-like taste in the product, which suggests that the retort processing of meat entr´ ee had introduced off-flavors reminiscent of fish into the product. Panelists who evaluated the Tuna Noodle Casserole product did not comment on such an off-flavor, but indeed a fish-like taste would not have been peculiar for that product. The extensive heat applied in retort processing typically results in an overprocessing of meat products, to ensure sterility throughout the entire product. Perhaps with the implementation of nonthermal processing methods, off-flavor development in these types of meat products could be avoided, and initial panelist acceptance of the products might be improved. This could ultimately serve to increase the shelf life of the meat entr´ ee products.

Texture changes affecting quality of representative products in storage were limited to moisture migration, starch gelatinization, and syneresis. These changes were most considerable for those products with discrete

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Special Edition on Space Food and Nutrition components (Tuna Noodle Casserole), and in products with high starch (Homestyle Potatoes) or protein contents (Grilled Pork Chop). Changes in consistency of fruit over time and a low panelist acceptability of texture in vegetable products were also observed. Although analytical texture data on the Homestyle Potatoes product were inconclusive, sensory data suggested that product texture immediately after production was unacceptable.

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Comments on product texture were consistent throughout the study, and assumed to be the result of potato tissue softening imparted by the retort process. Despite this perception of soft texture, panelist acceptance of initial flavor, aroma, and other quality factors was satisfactory and allowed maintenance of product quality throughout shelf life. Declines in flavor and aroma attributes, therefore, were determined to be the primary mechanisms of quality loss for Homestyle Potatoes. Decreased hardness of thermally processed potatoes relative to unprocessed control samples after retorting. They attributed this difference to solubilization of intracellular pectic substances, absorption of water, and gelatinization of starch granules. Prolonged storage of their processed potato samples indicated some hardness decrease due to a reduction of starch granule water holding capacity over time.

Another high starch product considered in the present study was the Three Bean Salad vegetable product.

Texture of this product was found to be quite stable over time, but was greatly degraded by storage at low temperatures. Storage at 40 ◦ F was found to result in gelatinization of filling aid starches, which shortened the shelf life of the product considerably to 12 month. With extended storage of the retorted product, and especially with exposure to freeze thaw cycling, cooked starches within retort product filling solutions can be prone to retrogradation. The retrogradation of the starch molecules that occurred in this product was initially observed through a slight thickening of the product sauce after 4 months of storage at 40 ◦ F. After 12 months of low temperature storage, retrogradation had proceeded to a level that rendered the product unacceptable to panelists. No significant texture differences were observed for this product throughout storage at ambient and high temperatures. Replacement of the starch used in this formulation and avoidance of low temperature storage of this product are proposed as countermeasures to realize the greatest shelf life for this product.

Changes to the textural quality of representative fruit products (Apricot Cobbler and Rhubarb Applesauce) were reflected in sensory ratings of each product’s texture, and were also presumed to have affected panelist ratings of appearance.Both fruit products were noted by panelists to have lost firmness and become thinner over time, with such effects being most pronounced at higher temperatures. This was assumed to be the result of moisture release from fruit tissues and a subsequent increase in free water in the products over time. An increase in free water of Rhubarb Applesauce was reflected in product thinning, as noted by an increase in Bostwick flow consistency over time. Free water release within the Apricot Cobbler product was less pronounced, likely because of the presence of ingredients that were able to capture the released water. An informal sensory analysis of the product at 48 months indicated that tapioca pearls (present at <2% w/w in the product) were noticeably swollen, as they appeared to have absorbed much of the water released from the apricot fraction of the product.

This evaluation also indicated that free water released from the apricots may also have been incorporated into the pie crust.This incorporation had resulted in softening, and even dissolving, of a considerable amount of the crust component by the end of the product’s shelf life.

Immediately after processing, panelists noted that the textures of 3 vegetable products (Carrot Coins, Sugar Snap Peas, and Roasted Vegetables) were not desirable. Panelist comments indicated that they found the products to lack freshness, citing that the vegetable components were "too soft," and "too moist." Similar comments were observed throughout storage testing, but could not be correlated to any data from instrumental textural analyses. It is likely that the comments addressed textural changes imparted to these vegetables by the retorting process itself, irrespective of storage time and temperature.

Entr´ ee (both meat and vegetarian) were among the most durable products considered. Texture loss in the representative entr´ ee (Grilled Pork Chop, Tuna Noodle Casserole, Palak Paneer) appeared to occur gradually, and was characterized primarily by sensory evaluation. Changes to the Grilled Pork Chop product were limited to an increasing hardness and dryness of the meat and thinning of the sauce over time. The observations were likely due to decreased water holding capacity of the meat proteins over time and gradual release and incorporation of water into the sauce. However, no conclusive analytical data were available to assess the rate of this deterioration. Texture data and free liquid measurements were very inconsistent. This is likely due to the addition of varying levels of sauce to the products, as sauce addition occurs as required to maintain acceptable pouch fill weights. Therefore, shelf life projections were accomplished primarily through consideration of sensory data. As sensory data are varied by their nature, shelf life calculations were performed conservatively to account for the lack of analytical data. A hardening of cheese cubes in the Palak Paneer vegetarian entr´ ee was also observed over time. Instrumental analysis of texture indicated a gradual hardening and decrease in cohesiveness over time for cheese cube samples over time. These changes were reflected in sensory texture

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scores, and were significantly more pronounced with high (95 ◦ F) temperature storage. As with other entr´ ee items, these changes are suspected to be the result of a decrease in water holding capacity of the proteins in the cheese cubes, and subsequent moisture release. Maintenance of refrigerated and ambient storage of this product appeared to slow this texture change. Authors have observed hardness decreases throughout storage of retorted paneer curry, but have acknowledged prior research that has characterized increase in hardness similar to the present study. Both studies observed most extensive texture decline with storage at higher temperatures.

Table 6 summarizes the levels of several storage labile nutrients observed in representative products after longterm storage at 72 ◦ F. Decline in vitamin C was the most significant loss observed for fruit products over time.

These losses were varied, yet were consistently more pronounced for products stored at ambient high (95 ◦ F) temperatures. Vitamin B losses were most significant for vegetable products, and showed no temperature dependence. Increases in carotenoid content were observed for Carrot Coins products stored at ambient and high temperatures. Vitamin B content of meat and vegetarian entrees showed considerable declines over time, with greatest losses occurring for products stored at ambient and high temperatures. Vitamin K was found to decline in Palak Paneer stored at ambient and high temperatures. Vitamin A levels in the Vegetable Quiche egg product appeared to decrease by 90% after 36 months of storage at all temperatures. The dessert product showed reasonable vitamin stability over time, with substantial losses only observed in pantothenic acid and the contents of several minerals.

Shelf Life Estimations for All NASA Retort Pouched Products Shelf life estimations of NASA’s current stock of retorted products are summarized in Figure 1. Fruit and dessert products were estimated to have a minimum shelf life between 1.5 and 5 years; vegetable side dishes were estimated to have a minimum shelf life between 1 and 4 years ; soups and starch side dishes were estimated to have a shelf life between 1.75 and 4 years; and dairy products and vegetarian entr´ ee are estimated to have a shelf life between 2.5 and 3.25 years. Meat products were found to be the most durable products, as they were all estimated to maintain quality for a minimum of 2 years, with an expected shelf life maximum of 8 years.

Of the 65 products, only 27 are estimated to have a shelf life of greater than 3 years, and would therefore fall within the minimum range required by AFT to support extended duration spaceflight. Additionally, there are likely to be mission scenarios requiring up to a 5 years shelf life for food. Supporting such a scenario with the current food system would allow only the provision of a limited number of entr´ ee products with shelf life estimates that extend beyond 5 years.

The bubble chart plots in Figure 2 are provided to represent the caloric and nutrient provisions that would be possible in various mission scenarios, based on the shelf life estimates of this study. Figure 2A represents a full landscape of foods in NASA’s thermostabilized product stock, with respect to each food’s caloric content and calculated nutrient density parameter. The size of the bubbles in these charts is defined with respect to the number of foods that exist in a given category. Calories are considered per 100 g of the food product. The nutrient density parameter for each food was defined internally, using NASA requirements for food system nutrition . The following 18 nutrients were considered in the definition of this parameter: vitamins A, C, D, E, K, B1, B2, B3, B6, B12, folate, biotin, pantothenic acid, calcium, magnesium, potassium, iron, and zinc. The level of each nutrient that was present per 100 g of food was compared against the corresponding NASA requirement, and points were awarded as follows: the presence of 10% to 49% of the NASA RDI of a given nutrient contributed 1 unit to the nutrient density, the presence of 49% to 99% of the NASA RDI of a given nutrient contributed 2 units to the nutrient density of the food, and a nutrient present in excess of 100% of the NASA RDI contributed

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Special Edition on Space Food and Nutrition 4 units to the nutrient density. The sum of the nutrient density units awarded to each product per its nutritional profile is represented in the nutrient density parameters plotted in menu landscapes of Figure 2. While Figure 2A represents the menu landscape of the full product stock of thermostabilized foods, Figure 2B represents a menu landscape comprised of only the food provisions that would be possible with a 3-years shelf life requirement for NASA missions.

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Furthermore, Figure 2C depicts the even more limited landscape of options that would be available to support a 5-years shelf life requirement. As is apparent from the progression of the charts in this figure, the menu landscape available to support a NASA mission becomes quite limited with increasing requirements for the shelf life of the food system.

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In fact, supporting a 5-years scenario with the current food system would allow the provision of a very limited number of meat entr´ ee products. Therefore, modification to the current food system will be required to ensure provision of an adequate food system in extended duration mission scenarios. Modification may be accomplished in terms of individual product reformulations, application of emerging nonthermal processing technologies, and development of low temperature options for food stowage volumes.

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BULK OVERWRAP PACKAGING SYSTEM NASA has established the goal of returning human expeditions to the moon and extending exploration to Mars.

Extended manned missions of these types require massive quantities of food to be flown into space. This presents two challenges when dealing with a food system. The first challenge is in maintaining the quality of the food throughout its shelf life which may be in excess of five years, and the second is to assure the mass and volume of the food system are minimized.

The current packaging and stowage system is adequate for the current, short duration missions involving high payload vehicles such as the Shuttle Transportation System (STS) and Russian Progress vehicles. Payload for long duration missions (years rather than months) will require a greater quantity of food in proportion to other supplies than do the missions of today, like the International Space Station (ISS) missions.

Thus, the need for reduced stowage mass and volume becomes critical in order to execute future mission.

The purpose of this project is to identify a low mass, flexible bulk overwrap system intended to maximize shelf life of food by preventing oxygen and moisture ingress, while minimizing volume and mass of the total system.

The research includes an evaluation of candidate packaging materials, oxygen scavenger systems, and pouch configurations as well as a corresponding feasibility assessment for proposed systems.

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Three materials were chosen for the study based on their barrier and physical properties: a foil laminate for its high barrier, a coated high barrier PET laminate for its high barrier and flexibility, and a PVDC laminate for its flexibility. Two different package configurations, a simple two sided pouch and a side gusted pouch, were chosen for the study. Each configuration was made by Technipaq Inc. from the three materials listed above.

Gusseted pouches provide a good material area to usable volume ratio and provide a preformed, cuboid shape for easy packing and stowage. The gusseted pouch dimensions chosen are 25"x12.5"x5.5" to mimic the dimensions of the current ISS Collapsible US Food Container (CUFC). A two sided pouch was chosen because it could provide different forming options for odd shaped configurations that could be used to fit in abnormal shaped locations of space vehicles. The two sided pouch dimensions are 24"x 25.5", which provide a similar volume to the gusseted pouch.

Two rigid fixtures were designed to allow for the formation and retention of shapes of the bulk overwrapped items during stowage and sealing. One fixture was made in the shape of a rectangular box with five sides from 0.25" plywood. This box was used with the gusseted pouch to aid in the stowage of food and help retain the cuboid shape of the gusseted pouch. The second fixture was constructed out of 0.25" plywood and 6 mil (.001" = 1 mil) pink poly to allow for the formation of a pie slice shaped package, which could possibly fit into odd shaped locations of certain space vehicles.

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Results of Bulk Overwrap System

Current results are promising. When comparing the bulk overwrap system to the current system used for ISS missions that uses individual overwraps, an average savings of 85 grams per container was achieved.

Another 700g per container of food could be saved if the bulk overwrap system was used in place of the ISS food containers. Vacuum sealing the bulk overwrap bags optimizes the volume by reducing it by approximately 18.7% and helps the package maintain its shape. Work is being continued on optimizing the atmosphere inside the system using oxygen scavengers and better materials [T. V. Oziomek,P. M. Catauro , BULK OVERWRAP PACKAGING SYSTEM].

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Effect of Processing and Subsequent Storage on Nutrition

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Comparative Packaging Study

Evaluate new high barrier food packaging films for use on long duration space missions.

Determine the effects of • High temperatures during heat sealing • Stress cracking from folds in the films caused by vacuum packing • Relative humidity during storage

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Flexible High-Barrier Polymers for Food Packaging (NNX10CB04C) The development of a polymer laminate with water and oxygen barrier properties suitable for food packaging and preservation on 3-5 year manned space exploration missions was proposed. The laminate is a multilayer structure comprising polymer and inorganic dielectrics that will provide near-hermetic encapsulation of food items for the duration of these missions.

In Phase I, flexible polymer barriers with an oxygen transport rate of <0.005 cc/m2 -day and water transport rate of <0.005 g/m2 -day were developed. The barriers contain no metal foils, have a areal density of <34 g/m2 for a 40 micron thick film, and tolerate high temperature sterilization treatments. The polymer laminates are mechanically robust exhibiting a 165MPa yield strength, 200MPa tensile strength, 550MPa tensile modulus, and 3% elongation to yield. In Phase II, investigators proposed to optimize barrier properties to reduce weight, minimize ash on incineration, develop heat-sealing methods, and expand the testing to include heat sealed enclosures. The Phase II effort also included collaboration with a potential high-volume manufacturer of the barrier films for aerospace applications.

The specific NASA applications for the proposed barrier polymers are the following: 1. food packaging for long-duration space missions; 2. packaging for medicines on long-duration space missions; 3. packaging of air and moisture sensitive chemicals used in science exploration on long-duration missions; 4. packaging of astronaut physiological samples; 5. packaging of extraterrestrial materials for return to earth.

All these applications will benefit from the availability of a lightweight, high-strength flexible packaging material. Besides having exceptional barrier properties, the proposed barrier polymers have several other features that are important to these NASA applications including: 1) transparency to allow inspection and identification of package contents; 2) an internal surface to which biocompatible and non-thrombogenic coatings can be added; and 3) a low temperature heat sealing capability that allows astronauts in space to create sealed packages that exclude water and oxygen and also prevent bacteriological and viral contamination.

RESULTS Non-NASA commercial applications in both the private and Government sectors have been identified. These applications included:

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Special Edition on Space Food and Nutrition 1. meals-ready-to-eat (MREs) packaging for the military 2. electronics packaging 3. flexible packaging for primary and secondary lithium, ion batteries 4. packaging of battlefield medical supplies for treating trauma (e.g. biologically active hemostatic agents) 5. very long storage of food and medicines in rapid response materiel caches 6. packaging emergency supplies at remote locations.

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Nutrient stability in space The research objectives of this study were to determine the stability of fatty acids, amino acids, and water and fat-soluble vitamins in supplements and in foods from the space food system after long-duration spaceflight on the ISS.

A total of 5 food items from the space food system (tortillas, salmon, almonds, broccoli au gratin, and dried apricots), a multivitamin, and a vitamin D supplement were used for this study. In the space food system, tortillas, almonds, and dried apricots are flown as natural food items, salmon is flown in its commercially available thermostabilized form, and broccoli au gratin is packaged and freeze-dried at the NASA Johnson Space Center.

The tortillas, almonds, apricots, and broccoli au gratin are typically packaged in a foil overwrap for spaceflight, and they were packaged that way for this study. Salmon was packed in its commercial packaging, which is also used for flight. The vitamin supplements were packaged in bags of 20 pills. Each bag of 20 pills and each food item represented 1 replicate. At the beginning of the study, 15 replicates of each food item or supplement were analyzed to serve as controls at time 0. The values from this analysis were compared (Table 1) with estimated values from the Nutrition Data System for Research (NDS-R) software, version 2005, developed by the Nutrition Coordinating Center, Univ. of Minnesota,Minneapolis,Minn., U.S.A. The temperature and relative humidity of the ISS from August 2006 through April 2008 were 25 Âą 2

â&#x2014;Ś

C

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(min: 21, max: 30 ◦ C) and 36 ± 3% (min: 27%, max: 47%). In-flight cumulative radiation exposures recorded on the thermoluminescence detectors TLD-100 (1 LiF:Mg,Ti) for the kits were 1.93 ± 0.03 (353 d), 44.12 ± 0.60(596 d), and 74.53 ± 0.85 mGy (880 d). Background radiation exposure in the environmental chamber where the ground controls were stored was determined to be 0.18, 1.54, 2.54, and 3.63 mGy for the kits stored for 13, 353, 596, and 880 d, respectively. The temperature and relative humidity of the chamber were 25 ± 0 ◦ C (min: 23; max: 30 ◦ C) and 39 ± 7% (min:17%,max: 62%) during the study period.

For reference, a comparison of the initial (time 0) food analysis of 15 replicates of the 5 food items used in this study with estimated values from the NDS-R software is presented in Table 1. The ground and spaceflight data for the tortillas, salmon, almonds, broccoli au gratin, apricots, multivitamin, and vitamin D supplement are presented in Tables 2-8. In the tortillas (Table 2), amounts of all of the vitamins analyzed (thiamin, riboflavin, niacin,and folic acid) decreased significantly over time. Although niacin was significantly lower at 596 d, the difference was not more than the %RSD of the assay. The amount of folic acid was about 45% lower after 880 d than in the initial analysis, and flight and ground samples were not significantly different.

Similar to the nutrients in tortillas, the amounts of most of the amino acids and vitamins analyzed in salmon (Table 3) were significantly lower after 353 d; however, most of the amino acid differences at that time point were not greater than the %RSD of the assay. The amount of vitamin B6 was lower in both groups after 596 and 880 d, and it was lower in the flight samples than the ground samples at 353 d only. No differences due to flight or time occurred for vitamin B12 or vitamin D. In almonds (Table 4), the amount of hexanal (a flavor indicator) was greater after 13, 353, and 880 d (both ground and spaceflight samples). Hexanal concentrations were higher in flight samples than ground samples at most time points. Many amino acids were significantly different after 880 d, but the differences were generally smaller than the %RSD of the assay.

In broccoli (Table 5), beta carotene, vitamin C, and vitamin K were all lower after 596 d. Folic acid was lower than baseline after only 13 d, and vitamin B12 was higher at that time and continued to be higher than baseline throughout the 880-d study. In dried apricots (Table 6), β-carotene was higher than baseline at the last 2 time points. Vitamin E was significantly lower in the flown apricots after 353 d of spaceflight, but it was not different from baseline at 596 or 880 d. Folic acid in the multivitamins (Table 7) was decreased from baseline at all time points for both ground and flight samples. Vitamin B6, riboflavin, vitamin A, vitamin B12, and vitamin C were all decreased after at least 353 d of storage. Vitamin D in the vitamin D supplement (Table 8) was lower than baseline at all time points for both groups during the study. Destruction of even a single vitamin in the space food system could be catastrophic to astronauts on a 3-y mission to Mars.

Authors found that long-duration storage had a much greater effect on nutrient stability than did spaceflight.

Many nutrients had statistically significant changes from baseline at a single timepoint, but the changes did not exceed the %RSD of the assay itself and therefore should not be interpreted as a real effect of time. Some changes, however, should be interpreted as a real effect of time because they exceeded the %RSD and were consistent over time. Some of the most striking of these changes were the approximately 50% decreases in folic

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acid and thiamin in tortillas. Other notable changes were the 15% to 20% decreases in folic acid and in vitamins K and C in broccoli au gratin. Riboflavin, vitamin A, and vitamin C in the multivitamin decreased 10% to 35%.

In almonds, hexanal increased 200%. The increase in hexanal indicates that an increase in lipid peroxidation occurred. These samples were not tested for sensory appeal, but lipid peroxidation could affect the flavor of the food items.

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Radiation on exploration-class missions to the moon and Mars will include densely ionizing, high-linear energy transfer radiation in greater abundance than in low Earth orbit, where the ISS is located. The ISS nutrient stability data presented here provide us with data about effects of radiation in low Earth orbit only, and the results clearly show that the highest radiation exposure in this study (74.53 mGy over 880 d), in low Earth orbit, did not affect nutrient stability. Time had a more profound effect on nutrient stability.

Ground-based evaluations of higher doses of radiation may be warranted but have their own limitations. In such evaluations, items are typically exposed to short high-dose bursts from one type of radiation source. Chronic low-dose exposure to mixed space radiation likely presents yet a different paradigm, especially in non living systems that cannot replenish their defenses against free radicals.

Negative effects of irradiation on vitamins and other chemicals in foods can be minimized by irradiating foods at freezing temperatures or by packaging products in inert atmospheres, but foods flown in space are not frozen or in inert atmospheres when they are exposed to radiation.

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The initial food analysis data are for the most part quite close to data from the Minnesota nutrient database. In salmon, vitamin D was found to be lower than the database amount (9.6 in contrast to 15.6 Âľg per 100 g). Vitamin D has received much attention in scientific journals and the mainstream press because of the reemergence of vitamin D deficiency as a public health issue, and the overestimation of vitamin D in the nutrient database adds another facet to the broader concern. The broccoli au gratin seemed to have the greatest amount of variation fromthe database,with the analyzed content of some nutrients being greater than that in the database and that of others being lower. This may reflect the composite nature of the item and the potential for nonhomogeneous distribution of food components. Clearly, the accuracy of the estimated content of vitamin D in foods, and the variation of the nutrient contents of some foods from the contents in the database, are confounding factors that need careful attention in food analysis.

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Effects of Gamma Radiation on Select Fresh Fruits and Vegetables There was generally no effect of γ-radiation (up to 10kGy) on the macronutrients, total antioxidant capacity, total phenolics, and alpha and beta carotenoids in fresh strawberries, tomatoes, carrots, and apples after 1 day of storage following irradiation.

However, longer storage (3 days) following radiation treatment caused a significant decrease (p<0.05) in the micronutrients at all radiation doses and also severe physical degradation (Figure 1).

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Ascorbic acid in fresh strawberries and tomatoes was degraded at radiation doses ≥ 10kGy, but the ascorbic acid in carrots and apples was generally stable after 1 day following irradiation.

It is hypothesized that the considerable alterations in the cell wall structures of the tomato and strawberry that occur during ripening could contribute to the sensitivity to higher radiation doses observed in this study.

Lycopene in fresh tomatoes was degraded at radiation doses ≥10Gy after 1 day following irradiation. Radiation dose, length of storage following radiation exposure, and type of produce all should be considered when designing a diet for quality and optimum micronutrient consumption.

Effects of Gamma Radiation on Select Air-Dried and Freeze-Dried Fruits and Vegetables The antioxidant capacity, ascorbic acid, phenolics, and carotenoids (alpha, beta, and lycopene) in air-dried tomatoes, carrots, and apples and in freeze-dried strawberries and apples were generally stable when exposed to γ-radiation up to 10kGy and stored at 25◦ C and 35◦ C for up to 6 months.

In contrast to the nutrient stability, sensory panelists could differentiate (with a 95% confidence limit) samples stored at 35◦ C from samples stored at 25◦ C for 6 months. The sensory panelists most preferred the appearance of samples stored at 25◦ C and least preferred the samples stored at 35◦ C for 6 months due to the darker colors and browning observed in these products.

Further study on the acceptability of shelf-stable products following radiation treatment and storage is recommended.

Effects of Gamma Radiation on Micronutrients in Carrot and Tomato Cultivars The effects of γ-radiation (0Gy-10kGy) on the micronutrients of different carrot cultivars (’Bolero’, ’Juwarrot’, and ’Nutri red’) and tomato cultivars (’Persimmon’,’Black Prince’, ’Dona’, ’Carmello’, and ’Roma’) were similar.

Ascorbic acid was generally stable in the carrot cultivars, but both ascorbic acid and lycopene in the tomato cultivars were significantly (p<0.05) affected by increasing radiation exposure.

Unlike the lycopene in tomatoes, the lycopene content in the ’Nutri red’ carrot cultivar was not affected by radiation doses up to 10kGy. Again, the considerable alterations in the cell wall structures of the tomato during ripening could contribute to its sensitivity to higher radiation doses. Compositional differences between cultivars also merit attention when selecting crops to optimize a diet.

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Breakfast Augmentation Rationing System (B.A.R.S.)

Without an adequate food system, it is possible that space crewmembersâ&#x20AC;&#x2122; health and performance would be compromised. It is clear that in developing adequate NASA food systems for future missions, a balance must be maintained between use of resources (such as power, mass, and crew time), and the safety, nutrition, and acceptability of the food system. In short, the food must provide the nutrients to sustain crew health and performance, must be acceptable throughout the course of the mission, must be safe even after cooking and processing, and must be formulated and packaged in such a way that the mass and volume are not restrictive to mission viability.

It is this delicate balance that frames the food system needs for our next mission and charts the work for NASA Advanced Food Technology.

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