Lycopene content and antioxidant capacity of tomato jam

Abstract

Tomato (Solanum lycopersicum) is the world's second largest vegetable crop after the potato and a major source of lycopene. Lycopene is a red carotenoid and an efficient free radical scavenger, which presence in the diet positively correlates with reduced risk of chronic diseases. Although tomatoes are usually used as a salad vegetable, more than 80 % of tomatoes consumption comes from processed products such as ketchup, tomato juice, pickled tomatoes, sauces etc. Jam is another possibility of tomato processing. Tomato jam was produced in an open 120 liters oil jacketed stainless steel kettle. The proportion of sugar to fruit was 1:2.5, while the final concentration was 65°Brix (Bx). Lycopene content was estimated spectophotometrically at 503 nm and concentration was calculated using molar extinction coefficient of 17.2 × 104 M-1cm-1. An examination of the antioxidant capacity of samples was performed using DPPH assay. Obtained results indicate that lycopene content of tomato jam was slightly lower compared to fresh ones (79.66 mg/kg in fresh tomatoes and 75.54 mg/kg in tomato jam), while antioxidant capacity has increased during processing (0.335 and 1.195 mM Trolox equivalents per kilogram of samples for fresh tomatoes and tomato jam, respectively). Moreover, heat processing of tomatoes could result in increased bioavailability of lycopene. Based on the results, it may be concluded that tomato jam can be a high-quality product which can be a desirable component of healthy diet