greenhouses I shade net I hydroponics I aquaponics
An increased awareness exist of the role of pre-harvest abiotic stresses on the quality of horticultural products and their retention, although there exists a need for more pertinent research and technological advances, especially under climatic change scenarios.
About eco-friendly technologies for retaining quality on postharvest produce
A
nother need for such research should be that consumers are looking for the nutritional values of fruits and vegetables, for example, their constituents such as carotenoids, flavonoids and other polyphenols, phenolic acids, and other phytonutrients, which are even more susceptible to variations in temperature, relative humidity, concentrations of oxygen, carbon dioxide, etc. An attempt was made to exemplify the main horticultural crop species; frequent reference to some of these is related to the level of scientific reports, which relates to their storability (pome fruits vs. stone fruits), short lifecycle (vegetables vs. fruits), and economic importance. An example of physiological mechanisms is climacteric (for example, tomato, apple, or banana) and nonclimacteric (strawberry, citrus, and grape berries) fruits. Among the large spectrum of biochemical and structural modifications during the growth and maturation of harvested plant parts, those with a major impact on global quality and storability are referred to and discussed how abiotic stresses affect these. We focus on the role of abiotic factors on processes related to structural modifications of the flesh due to de-polymerization of principal components of cell walls and loss of cell turgor, which affect texture. Other important processes involve modifications of nutritional and organoleptic value of fruits due to an
10 Undercover farming I
September/October 2020
increase in mono- and disaccharides following starch hydrolysis and/or de novo synthesis, biosynthesis of volatile compositions, and the degradation of organic acids. Modifications of colour due to a degradation of chlorophyll and accumulation of carotenoids and/ or flavonoids in relation to light and temperature levels at the farm level have received increased attention in recent research.
Controlled atmosphere storage of fruits and vegetables Controlled atmosphere (CA) storage commonly uses low oxygen (O2) levels and high carbon dioxide (CO2) levels in the storage atmosphere combined with refrigeration. In CA storage, inside a food storage room is the gas composition that continually monitors and adapts to maintain the optimum concentration within completely close tolerances. Because CA storage is capital intensive and expensive to operate, it is more appropriate for those foods that are
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agreeable to long-term storage such as apples, kiwifruit, and pears. CA packaging is the enclosure of food in a gas impermeable package inside which the gaseous environment with respect to CO2, O2, N2, water vapour, and other trace gases has been changed and is selectively controlled to increase shelf life. Considering the definition, there are no CA packaging systems in commercial use. However, using the combination of O2 and ethylene (C2H4) absorbers, together with CO2 release agents in packaging, at least during the early stages of the storage life of the packaged product, could be classified as CA packaging. Some functions exist for the generation and maintaining of CA including O2 removal, excess CO2 removal, and addition of air, to replace O2 consumed by respiration, removal of C2H4, and in some cases addition of CO2. Selection of the appropriate functions and devices for generating and maintaining CA depends on what horticultural produce is stored and the storage conditions required for each produce. Research has shown that CA storage has positive, negative, and no effect on certain quality aspects of fruits and vegetables, such as physiological disorders, flavour and off-flavour, acidity, C2H4 production, respiration rate, volatile compounds, phytochemical compounds, colour. Source: Agricultural University of Tirana, Albania
