Abstract

CABALLERO, Birina L; MARQUEZ, Carlos J  and  BETANCUR, María I. Effect of the freeze-drying on the physico-chemical characteristics of rocoto chili pepper (Capsicum pubescens R & P). Bioagro [online]. 2017, vol.29, n.3, pp.225-234. ISSN 1316-3361.

In order to foment the agroindustrial transformation of Capsicum pubescens, in this research we dehydrated rocoto chili peppers with and without seeds, harvested in the rural zone of San Cristobal Medellin, Antioquia (Colombia), through freeze-drying, and the properties in the final product were evaluated. Three times of the heating rate were programmed (temperature rise from 0.02 to 0.05 °C per minute during sublimation) using fruits with and without seeds. A split plot design was used with the programming in the main plot, and the presence of seeds in the subplot in a randomized block design with three replications. It was evaluated the physico-chemical properties of milled final product characteristics, moisture content (%), water activity (a_w), pH, acidity, color indicators CIE-L, and rehydration capacity (RC), as well as possible changes of the plant tissue using scanning electron microscopy. The moisture percentage, a_w, pH and acidity, did not differ among treatments (P≤0.05), reaching maximum moisture of 8.62 % and a_w of 0.33. The luminosity (L*) and chroma (C*) of the dried with respect to fresh fruit was improved. Attributes of color b* and h° increased as well. With the lower heating rate for freeze drying, the fruit with and without seeds presented higher RC. The seedless fruits required less time to reach both freezing and sublimation temperatures and showed higher values of most color indicators.

Keywords : Conservation; drying; rehydration capacity.

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