Effect of blue and ultraviolet-C light irradiation on bioactive compounds and antioxidant capacity of habanero pepper (Capsicum chinense) during refrigeration storage

The aim of this study was to evaluate the effect of blue and UV-C light as abiotic stress on bioactive compounds and antioxidant capacity of habanero pepper (Capsicum chinense) stored under close package and low temperature (4-5 °C). Habanero peppers were harvest at immature condition (green color), disinfected and irradiated with blue (0, 1.5 and 3 min) and UV-C (0, 0.5 and 1 min) light following a face-centered central composite design. Pepper were evaluated for color parameters, chlorophylls, total carotenoids, total flavonoids, phenolic compounds, total capsaicin and antioxidant capacity for 30 d. Color parameters indicate that low temperature and closed packaging maintain habanero pepper green color, corroborated by the low change in chlorophyll and total carotenoids during storage. On the other hand, both lights stimulated the synthesis of all bioactive compounds evaluated and consequently the antioxidant capacity. However, in some bioactive compounds such as chlorophylls and total carotenoids, the effect was appreciable only in the first days of storage. Habanero pepper treated with a combination of 3 min of blue light plus 0.5 min of UV-C light showed the higher bioactive compounds and antioxidant capacity during storage. At the end of storage, the proposed design indicates that 3 min of blue light treatment plus 0.43-0.92 min of UV-C light (depends of the compounds) was the optimal combination to increase habanero pepper bioactive compounds. This study is a first approach to evaluate the effect of combined irradiation treatment as abiotic stress to enhance habanero pepper bioactive compounds and its antioxidant capacity.