Determination of physiochemical, microbiological properties and antimicrobial effects of citrus juices fermented with lactic acid bacteria

The society, who is conscious about health and whose food preferences change, has increased its preference to foods that have proven to have additional benefits on human physiology and metabolic functions, apart from basic nutritional needs. For this purpose, it is necessary to increase the variety of fermented products known to reduce the risk of disease and to have therapeutic and supportive effects and to put them on the market. In this research, it was aimed to give functionality to citrus juices, which contain important sources in its composition, by fermenting it with lactic acid bacteria, and as a result, to obtain a new product with different sensory quality, nutritional value and antimicrobial properties. After adding %10 sugar water solution to the fruit juices obtained from orange (Citrus sinensis), tangerine (Citrus reticulata) and grapefruit (Citrus paradisi) fruits obtained from the neighborhood markets in and around Afyonkarahisar province, heat treatment was applied for 15 seconds at 75°C. Pasteurized fruit juices were fermented in an oven at 30°C for 48 hours with 9 different lactic acid bacteria. The final products obtained were stored at refrigerator temperature (0-4°C) until the analysis was completed. At every stage of the production process; physical, chemical and microbiological (antibacterial and antifungal) analyzes were performed. The pH and titration acidity values of the physicochemical analysis results after fermentation showed a negative correlative effect. The highest DPPH free radical scavenging activity (% reduction) was 47,779±25,79, and the highest total phenolic content (mg GAE/g sample) was 2743,61±415,36 in fruit juices fermented using L. plantarum bacteria. The highest antibacterial effect of citrus juices was on P. aeruginosa (22,55±2,29 mm zone diameter) and the highest antifungal effect was on M. racemosus (22,36±2,35 mm zone diameter), fermented using L. lactis detected in fruit juices