Estabilidade do ácido ascórbico e dos pigmentos da polpa de acerola congelada por métodos convencional e criogênico

Abstract

The objective of this study was to evaluate the stability of ascorbic acid and pigments of frozen acerola pulp using mechanical (conventional at -22.1°C) and cryogenics (immersion in steam of N 2 at -178.6°C and immersion in liquid N2 to -195.1°C) processes during 120 days storage at -22.1°C. Were determined the ascorbic acid content, total anthocyanins and carotenoids as well as instrumental color of the acerola pulp in natura, postfreeze and at every 30 days during the storage period. The levels of ascorbic acid were stable at all freezing methods, while the conventionally frozen sample presented the greatest reduction (16.45%) on carotenoids levels in comparison to the standard sample. The smaller difference in color (ΔE*) was observed for the sample frozen by immersion in steam of N 2, which demonstrated a reduction of 11.26% and 8.50% in the levels of carotenoids and anthocyanins, respectively, after 120 days storage at -22.1°C. According to the results, the cryogenic freezing in nitrogen vapor before the conventional process is a good alternative to higher retention of the pigments of the pulp.