Resumo

ALTAMIRANO-CARRANZA, AS et al. Effect of substrates on the kefir grain biomass production and antioxidant activity. Biotecnia [online]. 2022, vol.24, n.1, pp.157-163.  Epub 13-Jun-2022. ISSN 1665-1456.  https://doi.org/10.18633/biotecnia.v24i1.1614.

Kefir is a fermented milk with proven bioactivities and popularity worldwide. However, kefir grains biomass (KGB) limits its production. The present work investigated the effect of different substrates on the KGB increase and antioxidant activity (AC). Kefir grains were inoculated (9.0 ± 0.7 g/L) into nonfat goat milk (GMK), nonfat goat milk with brown sugar (GMBSK), cow (1 % fat) milk (CMK), and cow milk brown sugar (CMBSK). Fermentation of substrates was at 25 ± 3 °C, and stopped at ~4.7 pH. Sampling was at 0, 4 and 8 h incubation time, evaluating KGB kinetics, productivity, growth rate parameters, physicochemical composition changes, and antioxidant activity. Goat milk substrates kefirs had the highest AC values. GMBSK and GMK had 44.8 ± 1.4 % and 37.6 ± 3.6 % AC, respectively. GMK and GMBSK had the highest biomass increments, 147 ± 23 % and 136 ± 7 %, respectively. Also, GMK had the highest (p < 0.01) kefir grains biomass productivity, 2.49 ± 0.24 g/(L-h). Goat milk substrate has the potential to increase kefir grains biomass and to improve the bioactivity of kefir beverages.

Palavras-chave : kefir; substrates; antioxidant activity; kefir grain biomass.

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