Functional fermented fruit juice production and characterization by using water kefir grains

Area of Science:

• Food Science and Technology
• Microbiology
• Nutraceuticals

Background:

• Probiotic beverages offer health benefits and are increasingly popular.
• Water kefir grains are a symbiotic culture of bacteria and yeasts.
• Fruit juices provide a substrate for fermentation and potential bioactives.

Purpose of the Study:

• To produce and characterize probiotic beverages using water kefir grains fermented with various fruit juices.
• To evaluate the impact of fermentation on the physicochemical properties, microbial counts, and phenolic profiles of the beverages.
• To determine the suitability of dragon, apple, orange, and kiwifruit juices for creating functional, non-dairy probiotic drinks.

Main Methods:

• Fermentation of apple, orange, dragon, and kiwifruit juices using water kefir grains.
• Analysis of yeast, lactic acid bacteria (LAB), and mesophilic lactic cocci counts.
• Quantification of organic acids, particularly lactic acid.
• Determination of total phenolic content and antioxidant capacity.
• Identification of phenolic profiles using chromatography.

Main Results:

• Fermentation significantly altered microbial counts (yeast, LAB, mesophilic lactic cocci) and organic acid content.
• Dragon and kiwifruit juices showed high counts for specific bacteria after 48 hours.
• Up to 21 phenolic compounds were identified, with chlorogenic acid and rutin being prevalent.
• Lactic acid levels increased, reaching 9.03 g/L in fermented dragon juice.
• Ethyl alcohol content remained within non-alcoholic beverage limits.

Conclusions:

• Dragon, apple, orange, and kiwifruit juices are suitable substrates for producing non-dairy probiotic beverages with water kefir grains.
• Fermentation optimizes the microbial and phytochemical characteristics of these functional beverages.
• The study demonstrates the potential for creating diverse, health-promoting probiotic drinks from fruit juices.