Minimally processed watermelons: effect of UV-C light on color, firmness and gas headspace during refrigerated storage

Abstract

Watermelons (Citrullus vulgaris) are prized because of their high nutritional quality and flavor, but its size does not make them appropriate for individual consumption. Therefore, marketing them as a fresh-cut product is of interest, but to have a proper presentation, the tissue should be plump, firm and have good color. UV-C light, a clean technology, could be an alternative to prevent undesirable changes in this product.The objective of this work was to evaluate the effect of UV-C light treatments on color, texture and gas headspace of minimally processed watermelons.The inner tissue of the watermelons was cut into cubes of 3.5cm side and subjected to exposure to UV-C light with doses of 2.09 (T1) and 4.02 (T2) kJ / m2, placed on trays, covered with film and stored at 10 ° C. At initial time and every 2 days during the 8 days of storage, the samples were removed to make determinations of color with a colorimeter (Konica, Japan), firmness with a texture analyzer (Shimadzu, China) and gas headspace with a gas analyzer (Servomex, United Kingdom). All determinations were made by quadruplicate and the results were analyzed by ANOVA (p<0.05), comparing means obtained by Fisher test.The CO2 content increased significantly (p<0.05) from the sixth day of storage, being particularly high in Control and T1 samples at the end of storage (2.6 ±0.1% and 4.5±1.9% respectively). The a* and b* color parameters tended to decrease during storage, the biggest reductions were observed for T1 samples. Firmness showed slight variations in T2 samples which had an average value of 12.42±0.51 N, while Control and T1 samples had significant decreases at the end of storage.As treated samples with 4.02 (T2) kJ / m2 did not have significant changes in color and texture parameters, this treatment would be suitable for minimal processing.