A study on processing conditions of fermented acerola juice

Abstract

This study investigated some key processing steps of fermented acerola juice, including variety, maturity, enzyme treatment, sugar concentration and fermentation and pasteurization conditions. One or two-factor experiments were randomly designed to determine the most suitable processing variables based on the investigated parameters, including the content of vitamin C, sensory quality and physicochemical properties of the resultant juice. The results showed that the Brazil variety (Malpiphia emarginata D.C) had highest vitamin C content (1567.9 mg/100 g), followed by sour variety (Malpiphia glabra L.) (882.9 mg/100 g) and sweet variety (Malpiphia punicifolia L.) (630.4 mg/100 g). However, according to sensory evaluation results, the sour acerola juice after fermentation had the highest overall score, indicating to be the most suitable for processing. The fermented juice of sour acerola variety at 100% maturity had the highest sensory score and vitamin C content compared to other levels of maturity. In order to enhance the clarity of acerola juice, the addition of 0.15% pectinase enzyme (Pectinex ultra SPL, Novozymes) was the most effective compared to 0.05 and 0.1% (w/w) enzyme concentrations. The fermentation at 15oC in 48 hours with 22% sugar concentration and 0.1% commercial yeast (Saf-instant, France) obtained the highest quality fermented juice. The fermented product was pasteurized at 80oC for 10 minutes to stop fermentation process as well as to retain the color and taste of the fermented juice. The good quality of the fermented acerola juice, in terms of physicochemical, sensory and microbiological properties could be maintained for at least 6 months.