Short communication: Effect of different kefir grains on the attributes of kefir produced with milk from Costa Rica

Abstract

Kefir is an artisanal product that is gaining scientific attention due to its increase in consumption attributed to its potential health benefits. The effect on the quality attributes of kefir grains of different origin (household and commercial) and preserved with different methods (drying and freezing) was evaluated to standardize a domestic and semi-industrial process. Chemical (protein, lactose. lactic acid, ethanol, and acetic acid) as well as microbial properties (total plate count and total yeast count) were monitored during the experiment. Results show a statistical difference between the kefir grains in terms of acetic acid and ethanol percentages, which leads to the conclusion that there is a difference in the microbial populations that produce these products. Lactic acid, protein, and lactose parameters are statistically the same as well as the growth in biomass and the total population of yeast. Our results suggest that both types of kefir grains maintain a similar performance and that their metabolic capabilities are stable throughout time (taking into account that the household grains have been productive for years), meaning that domestic or semi-industrial processes could be easily standardized.

Characterization of Kefir Produced in Household Conditions: Physicochemical and Nutritional Profile, and Storage Stability

“…Our results showed a ten-fold higher growth, which shows a considerable disparity between a mathematical model and a real fermentation scenario. The growth behavior of our grains ( Figure 1 ) was contrary to the results found by Pop et al [ 56 ] using a grain inoculum of 4.5% ( w / v ) to ferment skimmed milk at 25 °C and showing a significant biomass decrease after 24 h. This may be justified by the fact that our study used semi-skimmed milk, thus making Pop’s justifications, nutrient depletion or increase acidity, less robust arguments to justify growth behavior of our grains. Moreover, the fat content of the milk may be of significant importance, as demonstrated by Schoevers and Britz [ 27 ], who reported that higher milk fat content impairs grain growth by inhibition of nutrient exchange.…”

Estudo comparativo de ativação dos grãos de kefir sob temperatura ambiente para a produção de leite fermentado

“…Segundo a Instrução Normativa n 46 de 2007 do Ministério da Agricultura, Pecuária e Abastecimento (MAPA), kefir ou kefir natural (como também pode ser chamado) é definido como um leite fermentado cuja fermentação se realiza com cultivos ácido-lácticas elaborados com grãos de kefir, Lactobacillus kefir, espécies dos gêneros Leuconostoc, Lactococcus e Acetobacter com produção principal de ácido láctico, etanol e dióxido de carbono. Também podem ser sintetizados no kefir, em menores quantidades, compostos como: diacetil, acetaldeído, etil e aminoácidos, substâncias estas que ajudam a trazer para o produto um sabor diferente dos demais leites fermentados (BRASIL, 2007;SAINZ et al, 2020).…”

Investigation of changes in culturable lactic microflora during freeze storage in cow and goat milk kefirs by high‐throughput sequencing

“…Kefir is a common fermented dairy beverage that contains both yeast and bacteria produced by the fermentation of water or milk with kefir grains (Rosa et al, 2017). Kefir has been produced for centuries, and due to the positive effects of its live microorganisms on health, it is preferred by many consumers (de Sainz et al, 2020; Mitra & Ghosh, 2020; Stanton et al, 2001).…”

“…positive effects of its live microorganisms on health, it is preferred by many consumers (de Sainz et al, 2020;Mitra & Ghosh, 2020;Stanton et al, 2001).…”