Beef hamburgers enriched in lycopene using dry tomato peel as an ingredient

The direct addition of dry tomato peel (DTP) to hamburgers may be useful both to obtain a new product enriched in lycopene and for providing a use for this by-product from the tomato industry. In this study, different amounts of DTP (0-6.0%w/w) were added to raw and cooked hamburgers, and the effects on the meat's physico-chemical and sensorial characteristics were studied. The maximum DTP concentration compatible with good sensory acceptability and high lycopene content was determined. Addition of DTP increased the colour parameters a(∗) and b(∗) of raw and cooked hamburgers, and modified all textural properties probably because of the presence of fibre. The hardness values of cooked samples was significantly higher in the batch containing 6% DTP (67.6N) than in a control batch (50.9N, p<0.05). The addition of DTP to 4.5% results in hamburgers with good overall acceptability and a lycopene content of 4.9mg/100g of cooked hamburger.