Abstract

MUNOZ-LOPEZ, Cinthia et al. Effect of freeze-drying conditions on the physicochemical Properties, pectin content, and rehydration capacity of plum slices (Spondias purpurea L.). Agrociencia [online]. 2018, vol.52, n.1, pp.1-13. ISSN 2521-9766.

The Mexican plum (Spondias purpurea L.) (classified as an exotic fruit( is native to southern Mexico and Central America. It has export potential due to its nutritional content and taste. Its commercialization is limited because it highly sensitive to physical damage during postharvest. Freeze-drying is an alternative that allows the industrialization of this fruit and extends its shelf life; but the quality of lyophilized products depends on the operating conditions. The objective of this study was to evaluate the effect of freeze-drying conditions on the physicochemical properties, pectin content, and rehydration of plum slices (beetroot and yellow ecotypes). The experimental design was a factorial randomized arrangement with three replications. The experimental unit was a plum sample from each ecotype. Samples were frozen at -5 and -20 °C (Tc) and lyophilized at 0.05 and 0.1 mbar (Pr) under laboratory conditions. Pr had a significant effect on the moisture content in both ecotypes, with values lower than 0.02 g H2O g s s-1. Tc significantly affected water activity. Luminosity increased with respect to fresh fruit as Tc decreased. Freeze-drying did not have a significant effect on pectin content. The correlation between Tc, Pr, and rehydration of beetroot plum slices was not significant. Tc had a significant effect on the rehydrated samples (water at 30 °C), and weakened the structure of the solid matrix of the yellow plum. Freeze-drying is a reliable method to dehydrate plums, with high-quality rehydration, suitable for preservation and a diversified use as snacks, or as an additional ingredient for cereals, yoghurt, and bakery products.

Keywords : Spondias purpurea L.; freeze-drying; rehydration; pectin; color.

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