The changes in nutritional quality and functional properties of raw pulp okara were studied during 0-72 h fermentation by using Actinomucor elegans in combination with Zymomonas mobilis, which were analyzed according to the changes in enzyme activity. The results showed that crude protein content and protein molecular weight of okara declined gradually. Soluble protein content increased first and then decreased, reaching the peak of 11.01 mg BSA/g at 60 h. Amino acid nitrogen content increased gradually and reached 0.31 g/100g at 72 h. The crude fat content gradually decreased from 0 h to 48 h of fermentation, and then remained at about 7%. The insoluble dietary fiber was gradually converted to soluble dietary fiber, and both stabilized after fermentation for 48 h, when the contents were 54.74% and 7.07%, respectively. The soluble total sugars content and reducing sugars content showed a decrease and then an increase, reaching 80.26 mg glucose/g and 7.55 mg glucose/g, respectively, at 72 h. The water holding capacity and oil holding capacity reached their peaks at 48 h of fermentation with 10.36 g/g and 6.04 g/g, separately. Water solubility and swelling capacity improved gradually, reaching 21.36% and 8.82 mL/g at 72 h of fermentation, respectively. The determination of enzyme activity revealed that microorganisms can produce proteases, lipases, and cellulases with gradually growing activity during the fermentation process, explaining the changes in nutritional quality and functional characteristics of raw pulp okara. The results of this research provide some theoretical and technical support for the microbial modification, process optimization, and product development of raw pulp okara.
[1] 范柳, 刘海宇, 赵良忠, 等.不同制浆工艺对豆浆品质的影响[J].食品与发酵工业, 2020, 46(7):148-154.
FAN L, LIU H Y, ZHAO L Z, et al.Study on the influence of different pulping processes on the quality of soymilk[J].Food and Fermentation Industries, 2020, 46(7):148-154.
[2] 杨蕊莲. 豆浆工艺优化及预处理对其品质影响研究[D].重庆:西南大学,2016.
YANG R L.Study on optimization of soymilk processing and effect of different pretreatment on the quality of soymilk[D].Chongqing:Southwest University, 2016.
[3] HU Y, PIAO C, CHEN Y, et al.Soybean residue (okara) fermentation with the yeast Kluyveromyces marxianus[J].Food Bioscience, 2019, 31:100439.
[4] 高天宇, 曾茂茂, 何志勇, 等.茯苓菌液态发酵改良豆渣风味研究[J].食品与发酵工业, 2021, 47(12):189-195.
GAO T Y, ZENG M M, HE Z Y, et al.Flavor improvement of okara by liquid fermentation with Wolfiporia cocos[J].Food and Fermentation Industries, 2021, 47(12):189-195.
[5] 白海军, 王颖.发酵法制备芸豆渣可溶性膳食纤维及其抗运动性疲劳作用研究[J].食品工业科技, 2022, 43(13):367-37.
BAI H J, WANG Y.Study on preparation of modified soluble dietary fiber of kidney bean by fermentation and its effect on anti-exercise fatigue[J].Science and Technology of Food Industry, 2022, 43(13):367-372.
[6] SU M, HU Y, CUI Y, et al.Production of β-glucosidase from okara fermentation using Kluyveromyces marxianus[J].Journal of Food Science and Technology, 2021, 58(1):366-376.
[7] VONG W C, AU YANG K L C, LIU S Q.Okara (soybean residue) biotransformation by yeast Yarrowia lipolytica[J].International Journal of Food Microbiology, 2016, 235:1-9.
[8] 姚粟, 于学健, 白飞荣, 等.中国传统发酵食品用微生物菌种名单的研究[J].食品与发酵工业, 2017, 43(9):238-258.
YAO S, YU X J, BAI F R, et al.Research on the inventory of microbial species in Chinese traditional fermented foods[J].Food and Fermentation Industries, 2017, 43(9):238-258.
[9] KHALID M, RUBAB N, AFZAL W, et al.Engineering of Zymomonas mobilis for Enhanced Biofuel Production[M].Bioenergy Research:Basic and Advanced Concepts,2021:155-181.
[10] 张瑜. 毛霉联合乳酸菌发酵对豆渣可溶性膳食纤维及其应用特性的影响[D].扬州:扬州大学,2020.
ZHANG Y.Effect of Mucor combined with lactic acid bacteria fermentation on soluble dietary fiber in soybean dregs and its application characteristics[D].Yangzhou:Yangzhou University, 2020.
[11] LI B, YANG W, NIE Y Y, et al.Effect of steam explosion on dietary fiber, polysaccharide, protein and physicochemical properties of okara[J].Food Hydrocolloids, 2019, 94:48-56.
[12] 李东华, 叶春苗, 李秀婷.少孢根霉固态发酵豆渣饮料的研制[J].食品工业, 2017, 38(4):17-20.
LI D H, YE C M, LI X T.The development of mold solid fermentation of soybean dregs of health beverage mutants[J].The Food Industry, 2017, 38(4):17-20.
[13] ONG A, LEE C L K.Cooperative metabolism in mixed culture solid-state fermentation[J].LWT, 2021, 152:112300.
[14] 管瑛. 雅致放射毛霉DCY-1固态发酵豆渣的营养及功能性研究[D].南京:南京农业大学,2016.
GUAN Y.Effects on nutrition and bio-functionality of okara by solid-state fermentation with Actinomucor elegans DCY-1[D].Nanjing:Nanjing Agricultural University, 2016.
[15] TAN Y, ZHANG R, CHEN G, et al.Effect of different starter cultures on the control of biogenic amines and quality change of Douchi by rapid fermentation[J].LWT, 2019, 109:395-405.
[16] REN X E, LI C, YANG F, et al.Comparison of hydrodynamic and ultrasonic cavitation effects on soy protein isolate functionality[J].Journal of Food Engineering, 2020, 265:109697.
[17] GUAN Y, WANG J P, WU J J, et al.Enhancing the functional properties of soymilk residues (okara) by solid-state fermentation with Actinomucor elegans[J].CyTA-Journal of Food, 2017, 15(1):155-163.
[18] ABDULLAH-AI-MAHIN,HOSSAIN S,ABDEL-RAHMAN M A,et al.Enhancement of nutritive value of tea leaf waste by solid-state fermentation with Lentinus sajor-caju[J].Journal of BioScience and Biotechnology, 2016, 5(3):231-236.
[19] 申春莉, 李曼, 沙见宇, 等.灵芝菌丝体固态发酵豆渣的营养成分变化[J].食品与发酵工业, 2019, 45(12):114-119.
SHEN C L, LI M, SHA J Y, et al.Nutrient changes in solid-state fermented okara with Ganoderma lucidum[J].Food and Fermentation Industries, 2019, 45(12):114-119.
[20] GAO C, BAI W F, ZHOU H B, et al.Metabolomic assessment of mechanisms underlying anti-renal fibrosis properties of petroleum ether extract from Amygdalus mongolica[J].Pharmaceutical Biology, 2021, 59(1):563-572.
[21] GUO Y T, LIU W, WU B G, et al.Modification of garlic skin dietary fiber with twin-screw extrusion process and in vivo evaluation of Pb binding[J].Food Chemistry, 2018, 268:550-557.
[22] 周亚楠, 柴贺, 初琦, 等.纳豆芽孢杆菌发酵豆渣营养成分变化研究[J].食品研究与开发, 2016, 37(23):170-174.
ZHOU Y N, CHAI H, CHU Q, et al.The variable pattern of nutrition components in Bacillus natto fermentation of bean residue[J].Food Research and Development, 2016, 37(23):170-174.
[23] WANG Q, SHEN P Y, CHEN B C.Ultracentrifugal milling and steam heating pretreatment improves structural characteristics, functional properties, and in vitro binding capacity of cellulase modified soy okara residues[J].Food Chemistry, 2022, 384:132526.
[24] 王霏霏, 王莎, 李丹林.豆渣发酵工艺优化研究及其腐乳产品开发[J].农产品加工, 2020(21):28-31.
WANG F F, WANG S, LI D L.Study on optimal fermentation process of bean dregs and development of sufu products[J].Farm Products Processing, 2020(21):28-31.
[25] CHU J X, ZHAO H, LU Z, et al.Improved physicochemical and functional properties of dietary fiber from millet bran fermented by Bacillus natto[J].Food Chemistry, 2019, 294:79-86.
[26] ELLEUCH M, BEDIGIAN D, ROISEUX O, et al.Dietary fibre and fibre-rich by-products of food processing:Characterisation, technological functionality and commercial applications:A review[J].Food Chemistry, 2011, 124(2):411-421.
[27] SONG Y, SU W, MU Y C.Modification of bamboo shoot dietary fiber by extrusion-cellulase technology and its properties[J].International Journal of Food Properties, 2018, 21(1):1 219-1 232.
