Scientific Research in School Volume 3 Issue 1 2021
Concentration of Lycopene in Different Varieties of Tomatoes Charlie Scholefield Barker College Tomatoes are an important source of antioxidants, involved in reducing the risk of many chronic diseases such as cancer. This is because they contain a large number of carotenoids. Lycopene is one of these, an organic compound that gives red fruits and vegetables their bright pigment. This report will outline the effect of different tomato varieties on the concentration of lycopene extracted. Data was collected on three different varieties: Truss, Roma, and Cherry tomatoes, and analysed with an ANOVA and a PostHoc Tukey test to determine whether or not there was a significant difference in the means of the three groups. The results supported the hypothesis, suggesting that there is a significant difference in the concentration of lycopene from different varieties of tomatoes. Literature review Lycopene (C40H56) is a naturally occurring organic compound found in many red fruits and vegetables such as tomatoes, watermelons, pink grapefruits, red carrots, and papayas (May, 2020). It is the molecule that gives these compounds their bright red pigment. It is a longchain hydrocarbon molecule with alternating single and double carbon-carbon bonds, as seen in figure 1, referred to as a conjugated structure (de Montemas, 2020). This makes it part of a group of molecules called carotenoids, which give colour to red, yellow, or orange plant parts. β-carotene, also found in tomatoes, is another member of this group.
Figure 1: Chemical structure of lycopene.
Free Radicals Free radicals are molecules capable of independent existence that contain at least one unpaired electron (Agarwal et al., 2014), which they can either donate or accept. This makes them both oxidants and reductants, causing them to be highly reactive (Lobo et al., 2010). They can be produced through normal metabolic processes, or exposure to external sources such as Xrays, ozone, cigarette smoking, air pollutants, and industrial chemicals (Lobo et al., 2010). When functioning normally, free radicals are useful in helping fight off pathogens, protecting the body from infections. However, when there is an imbalance between free radicals and antioxidants, excess free radicals can cause oxidative stress. This means they begin to react with
fatty tissue, proteins, and DNA (Agarwal and Rao, 2000) causing chain reactions that slowly damage cells. This can lead to harmful, chronic diseases such as atherosclerosis, asthma, diabetes, and cancer. Antioxidants Antioxidants are extremely beneficial in the way they prevent excess oxidation of free radicals from occurring. They effectively balance out the oxidative stress caused, preventing major problems from occurring in the body. This makes it important to maximise antioxidant consumption. Carotenoids are known for their antioxidant properties in humans. This means they can prevent slow damage to cells that occur as a result of excess free radicals. This is important in preventing harmful chronic diseases, such as cancer. Lycopene is one of the most potent antioxidants, often referred to as a free radical scavenger (Fish, Perkins-Veazie and Collins, 2002). Because of its structure, lycopene (and other antioxidants) can easily react with free radicals, essentially ‘cleaning up’ the number of them in the body when there is an excess. This helps prevent oxidative stress damage caused to cells, therefore reducing the risk of diseases like cancer. In particular, cancer is one of the leading causes of death in the western world. Lifestyle and diet are considered as major risk factors, with about 50% of cancers related to diet (Agarwal and Rao, 2000), resulting in 35% of cancer mortalities (Williams, 1999). Producers will therefore often look to increase lycopene concentration in their tomatoes, because of the antioxidant property the compound holds. Tomatoes with higher levels of lycopene have greater health benefits, appealing to consumers as a better choice. Tomatoes are one of the most widely grown vegetables on Earth, second to potatoes (Baliyan and Rao, 2013), Science Extension Journal • 115
