Okara as a culture medium and stabilizing matrix for freeze-dried and spray-dried Lactobacillus plantarum

G. QUINTANA, E. GERBINO, A. GOMEZ ZAVAGLIA

San Miguel de Tucuman

Simposio; V Simposio Internacional de Bacterias Lácticas (SIBAL). Alimentos, Salud y Aplicaciones; 2016

Centro de Referencia para Lactobacilos (CERELA)

Okara is a nutritionally valuable by-product (rich in high quality proteins, unsaturated lipids and dietary fiber, and also contains, minerals and oligosaccharides) produced in large quantities as result of soy milk elaboration. To valorize this agro-waste, this work proposes its use as culture and dehydration medium for L. plantarum CIDCA 83114.The okara used was freeze-dried to avoid spoilage, and its centesimal composition was determined. Two types of okara were used: whole and defatted (obtained after extracting okara lipids with diethyl ether). Both types of okara were suspended in water to obtain 5% w/w suspensions, and autoclaved. Each okara medium were inoculated with Lactobacillus plantarum CIDCA 83114 and incubated at 37°C for 24 h. The growth kinetics were followed by plate counting for triplicate. The stabilization of Lactobacillus plantarum CIDCA 83114 after drying and storage processes also were evaluated. Cultures in the stationary phase were neutralized and freeze-dried (with or without 250 mM sucrose) or spray-dried. Bacteria were plate counted immediately after freeze-drying or spray-drying and during storage at 4⁰C for 90 days. The growth kinetics of L. plantarum CIDCA 83114 in okara, defatted okara showed not significant differences with regard to the control grown in MRS. Concerning freeze-dried, microorganisms grown in whole okara were those that best overcame the process. The addition of sucrose enhanced the recovery of microorganisms grown in defatted okara and in MRS (controls) after freeze-drying and did not have a significant effect on microorganisms grown in whole okara (P˂0.05). In turn, bacteria grown in whole and defatted okara showed a better performance than the controls after spray-drying.Regarding storage, freeze-drying was the most detrimental process for bacteria grown in all the three culture media [freeze-dried (with or without 250 mM sucrose) or spray-dried]. The addition of sucrose improved the performance of microorganisms stored in the three conditions. The bacteria grown in whole and defatted okara spray-dried showed a better performance than the controls.As okara is an agro-waste obtained in large quantities, its use as culture medium provides a cost-effective strategy for the production of large quantities of starters. The good performance of okara as dehydration medium during freeze-drying, spray-drying and storage represents a further contribution to valorize okara. It provides an innovative matrix of high nutritional value as vehicle of L. plantarum CIDCA 83114, with promising industrial applications in the development of novel functional foods and feeds.