Development of Probiotic Psidium Guajava Beverage by Using Pediococcus Pentosaceus VNK-1 and its Bioactive Potential

Abstract

Nowadays, the demand for probiotics and their fortification in vegetables and fruit juices have been extensively studied because of wide acceptability by the consumers. Probiotic based non- dairy products have become boon to the current food industries for the development of fortified

and functional food products. The consumption of such probioticated products provides essential nutrients that manifest health benefits to the consumers and prevent them from milk-allergies, lactose-intolerance and regulates cholesterol levels in the body. Exploitation of lactic acid bacteria (LAB) for fermenting fresh fruit juices is a sustainable and inexpensive fermentation technology which aims towards increasing the nutritional values and enhancing organoleptic features as well as extending the shelf life of fermented products. Guava is nutritionally rich fruit, containing carotenoids, polyphenols and other antioxidants acting as free radical scavengers and rich source of ascorbic acid and organic acids such as malic and tartaric acid. In this study, a prominent lactic acid bacterium; Pediococcus pentosaceus has been isolated from the epicarp of guava fruit that was used for the fermentation of guava fruit juice for the aim of developing probiotic guava beverage. With the aid of morphological, molecular studies and evolutionary studies, the isolated LAB was identified as Pediococcus pentosaceus VNK-1 (GenBank Id: ON810480). Fortification of guava juice was done with efficient LAB aiming for enhancing its physicochemical properties. Response surface optimization (RSM) technique was used for optimization of lactic acid (LA) fermentation of guava juice to formulate probiotic beverage. On 4

th day, maximum LA production for sample A1 was found as 561.75 ± 1.44 μg/ml, and the microbial cell viability in the juice medium was 3.77 × 109 CFU/ml (9.58 log CFU/ml). While pH, °Brix and concentration of reducing sugar decreased throughout the fermentation period. Thus, natural and fresh guava juice have proven as suitable substrate for the growth of Pediococcus pentosaceus VNK-1 for the development of probiotic beverage at 24°C with enhanced phenolics (855.96 ± 12.37 μg GAE/ml), flavonoid content (2001.44 ± 10.59 μg QE/ml) and antioxidant activity (69.79 ± 0.04 %) as compared to the juice samples fermented at 37°C. Additionally, probiotic beverage has been able to diminish the growth of the test bacteria namely Bacillus megaterium, Staphylococcus aureus and Bacillus subtilis when juice was inoculated with 12% inoculum, incubated at 24°C and agitation provided with 60 rpm. Thus, above properties have shown potential to develop a novel probiotic guava beverage using Pediococcus pentosaceus VNK-1 that would be able to exert benefits to the host in terms of gastrointestinal health and increasing the shelf life of the product.