Minimally processed lettuces: extending shelf life through packaging and treatment with salicylic acid and sodium chloride solutions

Abstract

The use of postharvest treatments and packaging in minimally processed foods has been studied as a step to extend the shelf life of highly perishable products such as vegetables. In this context, this research aimed to evaluate the effect of packaging and immersion in calcium chloride (CaCl2) and/or salicylic acid (SA) solutions on the relevant physicochemical properties of minimally processed lettuce. A completely randomized factorial design was used; packaging (with and without vacuum), and immersion in solutions (2% CaCl2, 2mM SA, 2% CaCl2+2mM SA, and water as control) as independent study variables. The response variables were monitored for sixteen days, and the content of phenolic compounds was determined at the beginning and end of the storage period. The samples that showed less weight loss corresponded to the mixture of CaCl2+SA+vacuum packaging, while the treatment with CaCl2+vacuum packaging showed less degradation of compounds such as total chlorophylls (TC) and vitamin C (VC). This last treatment also significantly influenced the color of the product, obtaining a lower browning index in the samples evaluated. Finally, the lettuce treated with SA+CaCl2+ vacuum packaging and SA+vacuum packaging did not present caffeic acid (CA) and chlorogenic acid (CGA) content at the end of storage, while CaCl2+vacuum packaging exhibited a low content of caffeic acid and lower antioxidant capacity at the end of the evaluation period, which can be associated with a lower browning effect compared to the control treatments with water. According to the results obtained, it can be concluded that immersion in solutions and packaging effectively contributes to preserving the quality of minimally processed lettuce.