Physicochemical and functional characterisation of a food ingredient based on okara containing probiotics

Abstract

A functional ingredient (OI) was prepared from fresh okara (ORM) by fermentation in solid state with Lacticaseibacillus casei (ATCC 393). The aim of the present work was to determine the physical, chemical, and functional characteristics of OI. The final product, OI, was a stable powder with aw: 0.485 ± 0.003 and moisture content: 5.7 ± 0.7% (w.b.), mainly composed by cell wall material (62%, d.b. alcohol insoluble residue, AIR) and protein (38.1%, d.b.). The stabilisation and fermentation processes reduced significantly (p < 0.05) the AIR content of the ORM. Higher functional properties, swelling (SC), water holding (WHC) and oil holding (OHC) capacities (6.14 ± 0.01 g.cm-3; 5.4 ± 0.2 g.g-1; 3.4 ± 0.6 g.g-1, respectively), were observed in OI respect to the ORM. The probiotic initial count in OI was 10 ± 1 log (CFU.g-1) and could be safety stored at 25 °C, showing 7.5 ± 0.4 log (CFU.g-1) at 63 days storage. The cells resisted the simulated gastric and intestinal stress< 80% and< 65%, respectively. This property was maintained during the storage of OI. However, the adherence ability to Caco-2 cells decreased to ≈ 0.2% possibly due, in part, to the OI matrix interference. Overall, okara can be profit for developing functional ingredients containing L. casei cells, with the possibility of being stored safety at room temperature.