Development of synbiotic functional food using potential probiotic isolates with soymilk and mushroom extracts as prebiotics

Abstract

The food industry has shown a growing interest in the so-called functional foods due to increase in consumers’ demand for foods with pharmaceutical and nutraceutical functions, from the natural origin to avert various side effects from the traditional drugs for cardiovascular diseases (CVD), etc. Thus, this work aims to formulate products using probiotics and prebiotics together (synbiotic), which have cholesterol-lowering and antihypertensive properties. This study deals with the evaluation of curd and human fecal microbial isolates for their probiotic, in vitro hypocholesterolemic and hypotensive properties. The isolates having probiotic potential were then utilized to formulate synbiotic functional foods (soymilk-fortified tea curd, and shelf-stable dry functional foods) in combination with prebiotic rich soymilk and extracts of best compatible mushrooms, respectively. Then the effect of storage on their biochemical properties and sensory attributes was studied. The best probiotic potential was depicted by isolate CI1 Enterococcus faecium),HF1 and FS3 (both Lactobacillus plantarum strains). They also exhibited in vitro cholesterol reduction, and angiotensin-converting enzyme (ACE)inhibition thereby can be used to formulate therapeutic products having both hypocholesterolemic and hypotensive properties. CI1 and HF1were also found to be compatible with soymilk and P. florida mushroom extract. Hence, these two isolates were utilized for soymilk fortified tea curd formulation. Tea curd is a functional food providing the health benefits of tea polyphenols and the bioactive peptides mainly ACE inhibitory) produced by probiotic fermentation. The tea polyphenols showed varying degrees of stability during storage. Soymilk fortification significantly increased the
viability of probiotics in the curd plus it also increased the ACE inhibition. P. florida extract had highest β- glucan and very high inulin content in addition to high amount of eritadenine a hypocholesterolemic and hypotensive compound reported exclusively in edible mushrooms), and it showed the highest compatibility with CI1, which was proven by the
prebiotic activity score analysis. The main aim of the study was to formulate dry shelf stable synbiotic foods which do not require refrigeration for storage and transport, hence being highly economical. Synbiotic microencapsulation protects the probiotic bacteria in food products as well as en route colon. Two types of drying processes,lyophilization and spray drying, were utilized and compared for better preservation of probiotics’ viability as well as organoleptic properties of food matrices used for incorporation and storage. The synbiotic microcapsules incorporated food formulations were found to be very promising both in terms of viable cell load as well as sensory acceptability after long-term storage for ≥15 weeks. While spray dried synbiotic powder of CI1 and P. florida when incorporated into food formulations proved to be more acceptable and favorable due to long-term storage stability (even after 15 weeks of storage). This process may be employed in future for efficient production and commercialization of several dry shelf stable synbiotic functional foods by varying the sources of prebiotics, the dry food matrix used and the type of health-promoting probiotic bacteria.