Application of combined methods for enzymatic browning control of minimally processed pear (variety Blanquilla) (Spanish text).

摘要

In this study different combined methods were applied for development of enzymatic browning control in minimally processed pears (variety Blanquilla).; First of all, effects of thermal treatments applied with vapour and water solutions immersions at 87°C were evaluated through colour and mechanical properties in fresh fruits cylinders and stored at different conditions. Results do show that both treatments produced significant changes in samples colour and mechanical behaviour. The longer the treatment time, the greater the changes.; Subsequently, effectiveness of antibrowning agents application (citric and ascorbic acids) in osmotic and isotonic media was studied, by colour changes evaluation during refrigerated storage. The obtained results show that lightness (L*) and hue (hab*) parameters are the best indicators of browning degree in pear. Osmotic media (which are associated to produce partial dehydration) were not suitable for enzymatic browning inhibition, possibly by enhancing tissue osmotic stress. Moreover, neither citric or ascorbic acid resulted effective for Blanquilla pear enzymatic browning inhibition.; Finally, effectiveness of various antibrowning agents (citric, ascorbic, 4-HR, EDTA and isotonic solution) with and without calcium lactate, applied using the vacuum impregnation technique with neutral pH solutions, was analysed. Different quality parameters such as colour, mechanical properties, sensorial evaluation, shelf life, respiratory rate, volatile production and microbiological stability during refrigerated storage, were evaluated. Results showed that the use of antibrowning compounds combined with calcium salts were not effective to keep sample colour stability throughout the storage time. Nevertheless, application of such combinations leads to diminish impact process by slowing down respiration and enhancing microbiological stability of samples.