Functional fermented pomegranate juice by using autochthonous lactic acid bacteria

Abstract

Nowadays, the increase in the awareness of health care by the consumers and the emerge of popular food trends such as veganism and vegetarianism, and lactose intolerant people, lead to the development of new healthy foods. Fermented fruit juices have gained greater preference in the market because they are source of nutritional and bioactive compounds (vitamins, fibers, minerals, phenolic compounds). Pomegranate (Punica granatum L.) juice (PJ) is a rich source of dietary polyphenols including ellagic acid, tannins, anthocyanins, flavonoids and punicalagin, which is the bioactive molecule responsible for more than 50% of its potent antioxidant capacity. Pomegranate seed oil (PSO) could be used as source of punic acid, a conjugated linolenic acid (CLNA) isomer with high anticarcinogenic and immunodulating properties. Two lactic acid bacteria (LAB) strains isolated from fruits growing in the Northwest region of Argentina (Levilactobacillus brevis CRL2051 and Lactiplantibacillus plantarum CRL2030) were separately inoculated (~107 CFU/mL) in pasteurized PJ (60% v/v, pH 4.50 adjusted with NaHCO3 10%, w/v) supplemented with emulsified PSO [PSO: Tween 80 (2% v/v), 1:9 v/v]. Unfermented PJ was used as control. Fermentation was carried out at 30 °C for 48 h; the strains grew up to 109 CFU/mL (ΔpH =1.06) after that period. The consumption of sugars and the consequent production of organic acids (HPLC) were strain-dependent. A slight reduction in the initial phenolic content (7.57-0.52%; Folin-Ciocalteau) was observed in most of fermented samples, while the antioxidant capacity was preserved (DPPH, ABTS, FRAP). The total color difference (ΔE*) was more pronounced in the fermented PJ than in the control PJ. This study demonstrates that PJ represents a suitable matrix for the development of LAB, and can be used for the formulation of new fermented drink enriched in CLNA, with a conserved high antioxidant capacity and total phenolic content.