Lycopene Lab Report

Introduction Carotenoids are pigments that are found mainly in chloroplasts of plants and in some photosynthetic organisms. They are synthesised naturally in plants in order to absorb light during photosynthesis and protect plants against photosensitization. They are found in our diet, through eating fruit and vegetables and many serve as an important source of vitamin A in our diets, such as ß-carotene. The structure of the molecule determines the colour, photochemical properties, vitamin activity and its chemical reactivity on oxidising agents and free radicals. Caratonoids have many double bonds in which can undergo isomerisation. In nature they exists in all trans form but under the influence of heat, light or chemical reactions they can

It is a linear unsaturated hydrocarbon with 13 double bonds and 11 of those are conjugated double bonds; C40H56. It has two central methyl groups at position 1,6 and the remaining are in the 1,5 position relative to each other. Its conjugated polyene structure reduces the energy required for electrons to transition to higher energy states, this allows it to absorb shorter wavelengths of visible light and block the longer ones; this gives it its red colour. It lacks a ß-ionone ring structure, therefore has no vitamin A activity.
Tomatoes and tomato based products are the largest source of lycopene in the human diet despite other fruit and vegetables having higher lycopene contents (Gross, 1987, 1991; Mangels et al., 1993). The lycopene content in fresh tomatoes differ and it depends on the variety, maturity, environmental conditions and time of year they were produced (Heinonen et al., 1989; Gloud, 1992; Lurie et al., 1996). It has been recorded in some of the deeper red varieties to contain up to 15mg per 100g, however, on average tomatoes contain about 3-5mg per 100g (Hart and Scott, 1995). Despite fresh tomatoes containing high amounts of lycopene, more than 80% of lycopene consumed in the United States is derived from processed tomato products, such as tomato paste, juice, puree, sauce and ketchup (Gloud