Quality and shelf life assessment of a new beverage produced from water kefir grains and red pitaya

Abstract

In order to diversify the consumption of red pitaya, the objective of this study was to evaluate the shelf life of two formulations of non-alcoholic beverages fermented by water kefir using red pitaya and apple pulp as substrates. The beverages were stored at 7 °C for 28 days, with analyses every 7 days. The species of yeast and bacteria identified in the highest percentages were Brettanomyces bruxellensis and Liquorilactobacillus satsumensis. After 28 days of storage, the pitaya and the pitaya and apple fermented beverages showed a reduction of 9.15% and 5.25% in pH, an increase of 2.7 and 1.8 times in acidity, a reduction of 6.27% and 5.25% in the total soluble solids content and an increase of 2.5 and 1.9 times in alcohol content, respectively. The addition of apple pulp to the pitaya-fermented beverage enhanced the antioxidant capacity from 2.49 mMFe+2.100 mL-1 to 3.19 mMFe+2.100 mL-1 and the reducing capacity from 42.08 mgEAG.100 mL-1 to 62.01 mgEAG.100 mL-1. However, reductions in the bioactive activity of the beverages were observed during the storage time. Both formulations presented satisfactory scores in relation to all the sensory attributes evaluated. Therefore, red pitaya and apple can be used to produce a new functional beverage.