Different sources of sucrose in water kefir fermentation

Abstract

Abstract Kefir is a functional drink with potential market growth and several beneficial properties to the human body such as intestinal microbiota balance and anti-inflammatory properties. It is produced from grains that multiply from an initial culture of microorganisms that ferment sucrose, resulting in a slightly acidic, carbonated and low-alcohol beverage. The objective of this work was to use three different substrates for the fermentation (coconut, brown, and refined sugar) and to carry out analyzes of pH, titratable acidity (TA), and soluble solids content during 48 h of the process. In the grains, microbial biomass, dry mass content, and scanning electronic microscopy (SEM) were evaluated. Five fermentations were made for each sugar. The results showed differences in the use of sugar, concluding that there was a greater difference in relation to refined sugar and the others. Drinks fermented in coconut and brown sugar showed pH and acidity values within the ranges found in the consulted literature, with grain structures that provided good adhesion of microorganisms, which was not noticed in refined sugar grains. This may be due to the white sugar’s refining process involving chemical compounds, causing the sugar to have a high sucrose content but a low concentration of minerals and nutrients that favor grain growth. However, grains did not show a high mass gain, which may have been caused by the proportion of sugar/grain (40 g/26 g), temperature (27 °C), and time (48 h) used. Considering the aforementioned parameters, this pioneering study compared coconut, brown, and refined sugars. It was concluded that coconut and brown sugars were more suitable for the fermentation of the kefir drink, due to their similarities with the desired characteristics.

Keywords

• Brown sugar
• Coconut sugar
• Kefir grain
• Microbial biomass
• Microorganism
• Symbiotic drink