Alternative drying method for chontaduro pulp (Bactris gasipaes) by pulsed microwaves: Physicochemical analysis and kinetic model

Abstract

Chontaduro (Bactris gasipaes), is a species of palm common in Central and South America. This perishable fruit is classified as a drupe. The objective of this research was to evaluate pulsed-microwave drying effect on physicochemical properties and kinetic models of two chontaduro varieties (yellow and red). The results showed that fresh yellow and red chontaduros contained 55.01 % and 64.6 % of moisture, and 6.85 % and 7.03 % of protein, respectively. Both pulsed-microwave and convective drying (control) successfully produced dehydrated materials with moisture contents below 10 % and water activities around 0.2, indicating stable products. The pulsed-microwave drying required significantly less time to reduce the water content in the fruits than convective process. In drying kinetics, all mathematical models were suitable to describe the experimental data, with the Page model showing the highest accuracy according to R2 and lowest RSEM and χ2 values. pH, acidity, fat, fiber, and ash content did not show changes after drying. However, thermally sensitive compounds, as protein and β-carotenes, were affected. Samples after pulsed-microwave drying presented 3.63 % and 5.19 % of protein for yellow and red samples, respectively. β-carotenes were reduced until to 55.51 % by pulsed-microwave and 56.96 % for convective drying. Pulsed-microwave drying is an alternative method to obtain dried products with appropriate physicochemical properties, where the heat mechanism does not adversely affect food characteristics during a short processing time. The non-traditional drying methods are a viable alternative to obtain new dried products from conventional or non-conventional sources with good physical, chemical and nutritional properties, as an increasingly demanding market.