Polysaccharide production by kefir grains during whey fermentation

Area of Science:

• Food Science
• Microbiology
• Biotechnology

Background:

• Whey, a dairy byproduct, is rich in lactose.
• Kefir grains are symbiotic cultures of bacteria and yeasts.
• Lactose fermentation can yield valuable products.

Purpose of the Study:

• To investigate polysaccharide production from lactose during whey fermentation by kefir grains.
• To evaluate the impact of kefir grain concentration and temperature on fermentation and polysaccharide yield.

Main Methods:

• Fermentation of deproteinised whey using kefir grains (CIDCA AGK1).
• Varying kefir grain to whey ratios (10 and 100 g/l).
• Incubation at different temperatures and monitoring over 5 days.

Main Results:

• Kefir grains acidified whey and reduced lactose concentration.
• Kefir grain weight increased during fermentation.
• Water-soluble exopolysaccharide concentration increased with fermentation time and grain concentration.
• Optimal temperature for polysaccharide production was 43°C, but this decreased grain weight.

Conclusions:

• Kefir grains effectively ferment deproteinised whey, producing exopolysaccharides.
• Fermentation parameters significantly affect polysaccharide yield and kefir grain characteristics.
• Kefir fermentation offers a potential route for valorising whey into functional ingredients.