An alternative source of probiotics: Water kefir

Abstract

The aim of this review was to compile the origin and distribution of water kefir, its production, microbial diversity, fermentation dynamics, health effects, and its place in national/international food legislation. Water kefir is a traditional, slightly carbonated fermented beverage with a lactic acid content of up to 2%. It is obtained by fermenting sugar by kefir grains, which are white or yellowish in color and translucent in appearance. The types of microorganisms in the water kefir differ depending on the sugar, carbon sources, and fermentation conditions. It has a complex microbiota mainly consisting of lactic acid bacteria, acetic acid bacteria, and yeasts. In addition, fermented water kefir contains various metabolites, including sugar, fruit-derived components, lactic acid, acetic acid, ethanol, carbon dioxide, mannitol, vitamins, and amino acids such as arginine. As a non-dairy fermented beverage, water kefir emerges as an alternative source of probiotics for individuals with lactose intolerance, people with dairy allergic reactions, and vegan consumers. However, although consumer demands have driven the food industry to increase the production of water kefir, the most common production still relies on the traditional method due to some difficulties in the industrial-scale production process. On the other hand, more in vitro and in vivo studies should be carried out to reveal the health benefits of water kefir.

The composition of Tibetan kefir grain TKG-Y and the antibacterial potential and milk fermentation ability of S. warneri KYS-164 screened from TKG-Y

“…6 Researchers have also found that dairy products fermented by kefir have anti-cancer, antibacterial, anti-allergic, anti-diabetic, anti-inflammatory, antioxidant, and anti-hypertensive effects. 7,8 Additionally, kefir could improve the intestinal tract and digestive system and reduce lactose intolerance. 9…”

“…6 Researchers have also found that dairy products fermented by kefir have anti-cancer, antibacterial, anti-allergic, anti-diabetic, anti-inflammatory, antioxidant, and anti-hypertensive effects. 7,8 Additionally, kefir could improve the intestinal tract and digestive system and reduce lactose intolerance. 9 Kefir grains exhibit an irregular morphology, characterized by surface undulations, irregularities, or pronounced distortion, and possess a certain degree of elasticity and acidity.…”

Microbial viability and nutritional content of water kefir grains under different storage conditions

“…Water kefir is produced by fermenting a carbohydrate‐containing solution with water kefir grains (WKG) at 21–25°C for 48–96 h (Pendón et al., 2022 ). Various substrates could be used to obtain WK beverages, such as apple, mandarin, persimmon, quince, grape, kiwi, coconut, sugarcane juice, honey, grape molasses, ginger, and onion (Cufaoglu & Erdinc, 2023 ; Güzel‐Seydim et al., 2023 ; Lynch et al., 2021 ; Moretti et al., 2022 ; Pendón et al., 2022 ). In addition to the fermentation environment, various fermentation parameters related to WK production have been studied (Gökırmaklı et al., 2023 ; Laureys et al., 2018 , 2019 , 2021 ; Laureys & De Vuyst, 2014 , 2017 ).…”

“…Some of the microorganism groups in WKG exhibited probiotic properties (Angelescu et al., 2019 ; Koh et al., 2018 ; Romero‐Luna et al., 2019 , 2020 ). Previous studies have investigated the health impacts of consuming WK (Cufaoglu & Erdinc, 2023 ; Moretti et al., 2022 ). Several studies have shown that consumption of WK may have potentially favorable effects against irritable bowel syndrome (Gökırmaklı et al., 2023 ) and has gastro‐protective (Brasil et al., 2019 ), cholesterol‐lowering (Rocha‐Gomes et al., 2018 ), antidiabetic and antihyperlipidemic (Alsayadi et al., 2014 ), antimicrobial (Gonda et al., 2019 ), anti‐inflammatory (Hsieh et al., 2012 ), antioxidant (Alsayadi et al., 2013 ), and hepato‐protective properties.…”

Effect of Time Fermentation on The Microbiological Properties of Coconut Water Kefir

“…When these microorganisms are introduced to coconut water, they initiate a transformation that not only preserves the natural goodness of coconut water but also enhances its nutritional profile. These grains are used to ferment sugarwater mixtures and are now collectively referred to as "water kefir grains" or "sugary kefir grains" [8], the main microorganisms in the water kefir grain are lactic acid bacteria, yeast, and acetic acid bacteria. The broad usage of water kefir for preventing IBD (inflammatory bowel disease) [9], improving intestinal permeability [10], and reducing constipation and diarrhea [11] were mentioned in other articles.…”