Kinetics of the changes in the antioxidant potential of fresh-cut tomatoes as affected by pulsed light treatments and storage time

Abstract

The effects of pulsed light (PL) on the antioxidant capacity (AC) and bioactive compounds content of fresh-cut tomatoes (Lycopersicon esculentum Mill., cv. Daniela) were studied. Tomato slices were subjected to fluences of 4, 6 and 8 J cm−2 and stored over 18 days. Modified first-order and Gompertzian functions were used to explain the changes in the studied parameters as affected by PL-fluence and storage time.PL processing led to an increase in the contents of lycopene (up to 26.1% higher) and phenolic compounds (up to 4.3% higher) in comparison with untreated tomato slices, while vitamin C was notoriously depleted (p < 0.05). Those patterns were properly fitted by linear equations (R2 ≥ 0.95), while changes in the bioactive compounds contents through storage were well described by Gompertzian functions (R2adj≥ 0.94 and Af ≥ 0.99). AC of tomato slices significantly decreased as a consequence of PL-processing (p < 0.05) and subsequent storage (p < 0.05). The influence of PL on the initial AC of tomato slices was expressed by a linear model (R2 ≥ 0.95) while changes through storage were appropriately fitted by a first-order equation (R2adj ≥ 0.95 and Af ≥ 0.99). The higher the fluence applied, the greater the change in the AC and bioactive compounds contents of tomato slices over storage. The high correlation coefficients and the estimated kinetic constants seem to suggest that changes in the AC of PL-treated tomato slices over storage were mostly determined by vitamin C concentrations (r = 0.93–0.97) rather than by other antioxidant contents (r = −0.59 − −0.76). Industrial relevance:The efficacy of pulsed light (PL) to reduce microbial loads on fresh-cut vegetables is widely known. However, information about the impact of PL treatments on the physicochemical and nutritional aspects of those commodities is scarce. The results obtained in this work may contribute to identify optimal PL-treatment conditions to achieve healthy and fresh-like cut tomatoes. In general, tomato slices exposed to the highest PL-fluence (8 J cm−2) exhibited significant increases in lycopene and total phenolic contents, thus minimizing losses in the antioxidant capacity of fresh-cut tomatoes through 18 days of chill storage.