Enhancing the functional properties of soymilk residues (okara) by solid-state fermentation withActinomucor elegans

Abstract

(2017) Enhancing the functional properties of soymilk residues (okara) by solid-state fermentation with Actinomucorelegans, CyTA -Journal of Food, 15:1, 155-163, DOI: 10.1080/19476337.2016 To link to this article: https://doi.org/10. 1080/19476337.2016 College of Food Science and Technology, Nanjing Agricultural University, Nanjing, P. R. China ABSTRACTIn this study, the food-grade fungal strain DCY-1 was isolated from Chinese traditional fermented soymilk residues (okara) and identified as Actinomucor elegans. The novel strain was used in the solid-state fermentation (SSF) of okara to improve their functional properties. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and reverse-phase high-performance liquid chromatography (RP-HPLC) analyses showed that okara proteins were degraded into peptides during fermentation. SSF okara showed high antioxidant activities, which included reducing power, ferrous ion-chelating activity, and scavenging effect of DPPH, ABTS, and hydroxyl radicals. Compared with the control, the antioxidant activities mentioned above increased by 4.29, 2.32, 3.45, 1.55, and 1.63-fold, respectively. SSF okara also showed a significantly higher ACE-inhibitory activity (61.17% ± 0.94%) at the end of fermentation. Therefore, SSF can be employed as a valuable process to obtain bioactive ingredients from okara, which would encourage their utilization in the formulation of value-added functional foods.Mejorando las propiedades funcionales de los residuos de leche de soja (okara) mediante fermentación en estado sólido con Actinomucor elegans RESUMEN En este estudio, la cepa fúngica de calidad alimentaria DCY-1 se aisló de los residuos de leche de soja tradicional china fermentada (okara) y se identificó como Actinomucor elegans. La nueva cepa se utilizó para la fermentación de okara en estado sólido (SSF) para mejorar sus propiedades funcionales. Los análisis SDS-PAGE y RP-HPLC mostraron que las proteínas de la okara fueron degradadas a péptidos durante la fermentación. La okara SSF mostró un alto nivel de actividades antioxidantes, las cuales incluían: el poder reductor, la actividad quelante del ión ferroso, además del efecto de barrido de radicales DPPH, ABTS y hidroxilo. En comparación con la muestra control, las actividades antioxidantes mencionadas anteriormente aumentaron a 4,29; 2,32; 3,45; 1,55 y 1,63 veces, respectivamente. La okara SSF también mostró una actividad inhibitoria ACE significativamente alta (61,17% ± 0,94%) al final de la fermentación. De este modo, SSF puede ser utilizado como un proceso valioso para obtener ingredientes bioactivos de la okara, los cuales podrían favorecer su utilización en la formulación de alimentos funcionales con valor añadido. ARTICLE HISTORY

In vitro study of the antioxidative and antiproliferative capabilities of Lactobacillus casei 16‐fermented soymilk

“…These microbes could hydrolyze the glucose moiety of isoflavones conjugates due to β-glucosidase and promote biological activity of soybean products (Pham & Shah, 2008;Wei, Chen, & Chen, 2007;Zhai et al, 2014). The proteins in soybean products could be hydrolyzed into peptide or free amino acid duo to the protease of the starter cultures (Guan et al, 2017).…”

Degradation of anti‐nutritional factors and reduction of immunoreactivity of tempeh by co‐fermentation with Rhizopus oligosporus RT‐3 and Actinomucor elegans DCY‐1

“…The four strains investigated ( Rhizopus oligosporus RT‐3, Actinomucor elegans DCY‐1, Neurospora crassa and Rhizopus oryzae ) for the fermentation of soybean were isolated from solid‐state fermented foods and were identified by morphological characterisation and rDNA‐ITS fragments sequencing (Jiang & Dong, ; Xiao et al ., ; Guan et al ., ). Raffinose and stachyose were purchased from Sigma‐Aldrich Chemical Co. (St. Louis, MO, USA).…”

Enhanced antioxidant activity of okara through solid state fermentation of GRAS Fungi

“…The enhancements that are specifically related to the increased antioxidant activities were 254% more free amino acids, 179% more isoflavone aglycones and 197% more free phenolic acids. Moreover, Guan et al (2016) used Actinomucor elegans DCY-1 to ferment okara. They assumed that proteins were hydrolyzed into peptides during fermentation.…”

“…Additionally, for the extracellular protease to work optimally a smaller particle size will enhance the access of the enzyme molecules to the protein located within the okara particles. Thereby, a higher degree of proteolysis will be pronounced that leads to the production of bioactive peptides (Guan et al, 2016;Yokomizo et al, 2002). About 815 ppm and 456 ppm of fermented okara (respectively by R. oligosporus and A. Oryzae), were equivalent with 1.0 ppm of ascorbic acid in terms of antioxidant capacity.…”

“…Most of the goals are to enhance okara's antioxidant properties, flavour properties, protein digestibility, production of antibiotic, etc. (Guan et al, 2016;Dhno et al, 1996;Vong et al, 2018).…”