Development of fermented beverage with water kefir in water-soluble coconut extract (Cocos nucifera L.) with inulin addition

Abstract The use of water-soluble plant-based extracts is a viable option of a non-dairy substrate in developing new food products, such as for kefir fermented beverage. The aim of this study was to develop a vegan fermented beverage with water kefir in the water-soluble coconut extract (WSCE), with inulin. A factorial design 23 was applied, with independent variables: coconut sugar (2.0; 6.0 and 10.0% w/v); inulin (2.0, 2.5 and 3.0% w/v) and xanthan gum (0.0; 0.13 and 0.26% w/v) and dependent variables: growth of kefir grains, fermented beverage yield and lactic acid. The growth of kefir grains was higher when the concentrations of inulin were close to 2.8 and 3.0% (w/v) and xanthan gum up to 0.26% (w/v), influencing in 90% the rate growth. Fermented beverage yield and lactic acid were between 80 to 82.5% and 1.2–1.25%, respectively, when of xanthan gum and coconut sugar were between 0.26 and 10.0% (w/v). Still, fermentative process was significant in terms of nutritional and enzymatic contents. The water kefir showed great potential for adaptation to WSCE in 24 h of fermentation, favoring the development of a non-dairy fermented beverage that may prove to be an alternative for lactose intolerant, allergic and vegans.