Okara: A Nutritionally Valuable By-product Able to Stabilize Lactobacillus plantarum during Freeze-drying, Spray-drying, and Storage

Abstract

Okara is a nutritionally valuable by-product produced in large quantities as result of soymilk elaboration. This work proposes its use as both culture and dehydration medium during freeze-drying, spray-drying, and storage of Lactobacillus plantarum CIDCA 83114. Whole and defatted okara were employed as culture media for L. plantarum CIDCA 83114. The growth kinetics were followed by plate counting and compared with those of bacteria grown in MRS broth (control). No significant differences in plate counting were observed in the three media. The fatty acid composition of bacteria grown in whole and defatted okara showed a noticeable increase in the unsaturated/saturated (U/S) fatty acid ratio, with regard to bacteria grown in MRS. This change was mainly due to the increase in polyunsaturated fatty acids, namely C18:2. For dehydration assays, cultures in the stationary phase were neutralized and freeze-dried (with or without the addition of 250 mM sucrose) or spray-dried. Bacteria were plate counted immediately after freeze-drying or spray-drying and during storage at 4°C for 90 days. Freeze-drying in whole okara conducted to the highest bacterial recovery. Regarding storage, spray-dried bacteria previously grown in whole and defatted okara showed higher plate counts than those grown in MRS. On the contrary, freeze-dried bacteria previously grown in all the three culture media were those with the lowest plate counts. The addition of sucrose to the dehydration media improved their recovery. The higher recovery of microorganisms grown in okara after freeze-drying and spray-drying processes and during storage was ascribed to both the presence of fiber and proteins in the dehydration media, and the increase in U/S fatty acids ratio in bacterial membranes. The obtained results support for the first time the use of okara as an innovative matrix to deliver L. plantarum. Considering that okara is an agro-waste obtained in large quantities, these results represent an innovative strategy to add it value, providing a symbiotic ingredient with promising industrial applications in the development of novel functional foods and feeds.

Valorization of okara oil for the encapsulation of Lactobacillus plantarum

“…Dehydrated okara contains about 9-10% humidity, 21% proteins, 55% whole fiber, 1.5% ash and 13-14% fats and oils (Quintana, Gerbino, & Gomez-Zavaglia, 2017). Because of the nutritional value of its components (proteins of high nutritional value, dietary fiber, antioxidants, unsaturated lipids), okara appears as a valuable source of different ingredients for the formulation of functional foods (Vong & Liu, 2016).…”

Bioactive components, in vitro digestibility, microstructure and application of soybean residue (okara): a review

“…The structural study of okara flour was previously investigated using various techniques, including scanning electron microscopy (SEM; Porcel et al, ; Voss et al, ; Santos et al, ) and Fourier transform infrared (FTIR) spectroscopy (Kamble et al, ; Li et al, ; Quintana, Gerbino, & Gómez‐Zavaglia, ). SEM is a useful technique for determining the microstructure of food products by evaluating the arrangement of starch granules within the protein matrix (Kamble et al, ).…”

“…FTIR spectroscopy may show structural similarities or differences between samples based on the presence or absence of specific functional groups (Rani, Singh, Kamble, Upadhyay, & Kaur, ). Quintana et al () studied the FTIR spectra of frozen whole and defatted okara specimens in the 4,000–500 cm −1 wavelength range. FTIR spectrum of frozen okara showed the existence of bands of lipids and carbohydrates.…”

Protective Effects of Tropical Fruit Processing Coproducts on Probiotic Lactobacillus Strains during Freeze-Drying and Storage

“…Despite the increased interest in antioxidant and prebiotic components naturally present in fruit processing coproducts [5,18], studies on the protective effects of these materials on probiotic cells during exposure to dehydration processes are scarce. Only one previous study reported the stabilizing effects of okara, a coproduct from soy milk elaboration, on Lactobacillus plantarum during freeze-drying [19]. Considering these aspects, this study evaluated whether coproducts generated during the processing of acerola, cashew, and guava can exert protective effects on probiotic Lactobacillus strains during freeze-drying and storage.…”