Valorization of berry pomace for extraction of polyphenol compounds and its co-encapsulation with probiotic bacteria

Saskatoon berry pomace, an antioxidant rich byproduct, may be suitable for nutraceuticals and functional foods. The present study aimed to co-encapsulate polyphenol-rich berry extract with probiotics to utilize the polyphenolic compounds present in berry pomace. The major benefit of co-encapsulation is that polyphenolic compounds increase the survival characteristics of probiotic bacteria in gastrointestinal tract. To make the process cost-effective, a conventional solvent extraction method was used for extraction of polyphenolic compounds from berry pomace. Spray drying was used to co-encapsulate polyphenols and probiotics by using plant-based carrier materials (pea protein isolate with gum Arabic). Spray dried powder was evaluated for encapsulation efficiency, gastrointestinal stability, bio-accessibility index, along with functional, structural and thermal characteristics. Berry pomace was found to be a good source of TPC, DPPH and ABTS with 2.49 mg GAE/1 g, 4.48 mg QE/1 g and 2.96 mg QE/1 g, respectively. The encapsulation efficiency (retention of polyphenolics and bacteria in capsules) of polyphenolic compounds and probiotics was 72.6% and 94.4%, respectively. Probiotic cells encapsulated with polyphenolic compounds showed improved survival (9.08 log CFU/mL) during in vitro gastrointestinal digestion. The bio-accessibility of TPC was 63.6% after intestinal digestion. The spray dried powder was observed to possess good thermal stability but poor functional properties, thus limiting applications to products such as bakery goods, sports bars, cereals and other foods where dispersibility is not imperative. Therefore, co-encapsulation by spray drying method offers an efficient and cost-effective method for simultaneous delivery of bioactive compounds and probiotics to the gut, extending their benefits by this combination.