Okara, soybean residue, prevents obesity in a diet-induced murine obesity model

Valorization and food applications of okara (soybean residue): A concurrent review

Agriculture waste is rising continuously across the globe due to enormous industrial, food processing, and household activities. Proper valorization of this waste could be a promising source of various essential bioactive and functional ingredients. Okara is a major residue produced as result of soybean processing and has a rich nutritional profile. The nutritional profile of okara is affected by the processing conditions, variety, pre-treatment, post-production treatments, and processing techniques. Owing to the high fibers, lipids, proteins, and bioactive components, it is being used as an essential industrial ingredient in various food processing industries. The prebiotic potential and nutritional profile can be increased by various techniques, that is, enzymatic, chemical, biotransformation, high-pressure microfludization, and fermentation. The prebiotic potential of okara makes it suitable as a therapeutic agent to prevent a variety of metabolic disorders such as diabetes, obesity, hypercholesterolemia, and hyperlipidemia. The current review highlights the structural, nutritional, functional, therapeutic, and industrial applications of okara.

Soybean Processing Wastes: Novel Insights on Their Production, Extraction of Isoflavones, and Their Therapeutic Properties

Soybean processing waste (SPW) has potential as a sustainable source of phytochemicals and functional foods. A variety of phytochemicals, nutrients, and minerals have been characterized from SPW using various analytical methods. SPW utilization strategies may provide a new way to increase production of bioactive compounds, nutritional supplements, and cosmetic ingredients. SPW has the potential for value-added processing, to improve commercial use, and to lower environmental pollution through proper use. Okara, a byproduct generated during soybean processing of tofu and soy milk, is rich in dietary fiber, isoflavones, and saponins. Isoflavones, an important class of biologically active compounds owing to their multifunctional and therapeutic effects, are extracted from SPW. Further, studies have shown that okara has potential prebiotic and therapeutic value in lowering the risk of noncommunicable diseases. Therefore, in this review, we focus on several extraction methods and pharmacotherapeutic effects of different SPWs. Their effective uses in functional foods, nutraceuticals, and health applications, as biocatalysts, and as value-added resources have been discussed.

Combination of α-Glycosyl-Isoquercitrin and Soybean Fiber Promotes Quercetin Bioavailability and Glucagon-like Peptide-1 Secretion and Improves Glucose Homeostasis in Rats Fed a High-Fat High-Sucrose Diet

This study examined the effects of a combination of soybean fiber and α-glycosyl-isoquercitrin (AGIQ) on improving quercetin bioavailability and glucose metabolism in rats fed an obesogenic diet. For 9 weeks, rats were individually fed a control diet, a high-fat high-sucrose (H) diet, H with soybean fiber (HS), or with AGIQ (HQ), or with both (HSQ). Quercetin derivatives in plasma, feces, urine, and cecal content were quantified by high-performance liquid chromatography to assess the bioavailability of quercetin, and meal tolerance tests were performed to assess postprandial glycemia and glucagon-like peptide-1 (GLP-1) responses. The HSQ group had higher plasma quercetin levels than HQ. The postprandial glycemia was attenuated in the HSQ group when compared to the H group. The basal plasma GLP-1 concentrations positively correlated with plasma quercetin derivative concentrations. Hence, the combination of soybean fiber and AGIQ could be beneficial for reducing the risk of glucose intolerance, possibly involving enhanced quercetin bioavailability and GLP-1 secretion.

The Effect of Tempe Gembus on High-Sensitivity C-Reactive Protein and Adiponectine Levels in Rats with Metabolic Syndrome

Metabolic syndrome can affect the inflammatory state which results in increased high-sensitivity C-reactive protein (hs CRP) and decreased adiponectin levels. Tempe gembus is a functional food that can reduce the risk of metabolic syndrome through the inflammatory pathway. This study applied a quasi experimental method, with a post-test only control group design. Sprague Dawley rats (n=30) were divided into 2 control groups (K- and K+) and 3 treatment groups (P1, P2, P3) which were given a 4-wk diet that included 2.5 g (P1), 5 g (P2), and 7.5 g (P3) of tempe gembus. Adiponectin and hs CRP levels were measured with ELISA. Statistical analysis was done with a one-way ANOVA test and a Kruskal Wallis test. It apprears that administering tempe gembus in these amounts can reduce the hs CRP levels (p=0.037) and increase adiponectin levels in rats with metabolic syndrome (p=0.008). This research has shown that a 2.5 g of tempe gembus can have a strong effect on hs CRP and 5 g of tempe gembus have a strong effect on adiponectin.

Tempeh Gembus Cookies as an Alternative Snack for Adolescent Girls With Obesity

Background: Tempeh gembus is a food that high in protein and fiber but low in fat. The low content of fat in tempeh gembus is good for adolescent with obesity. Tempeh gembus cookies could be the alternative snack for adolescent girls with obesityObjectives: To analyze the effect of the substitution of tempeh gembus flour on the nutrient content of tempeh gembus cookies and the acceptability of the best formula on the tempeh gembus cookiesMethods: This was an experimental research with one factor complete randomized design, which was the formulation of cookies with tempeh gembus flour of 0%, 25%, 50%, and 100% as the variation of substitution, then analyzed the nutrients and acceptance. The statistic method used were One-way Anova test to analyze the nutrients and Friedman test to analyze the acceptanceResults: There were significant effects the formulation of cookies with tempeh gembus flour on total fat, carbohydrate, total crude fiber, ash content, and reducing sugar. In acceptance test, there were significant effects of tempeh gembus cookies formulation on color, appearance, tenderness, aroma, and flavorConclusions: Cookies with tempeh gembus flour formulation of 100% was the best formulation to meet total energy, carbohydrate, low fat and high fiber acceptance which were good for adolescent girls with obesity. Whereas cookies with tempeh gembus flour formulation of 25% and 50% based on acceptance were still acceptable and preferred                                                                                                                                         

Improving Diet Quality for Chronic Disease Prevention With Okara "Food Waste"

There is a large amount of food waste in the United States, with high financial and environmental costs. Okara, also known as soybean (curd) residue or soy pulp, is the byproduct of tofu and soy milk, has high nutrition value, and is available at a reasonable price. While it is often disposed, it may instead be incorporated into our daily diet in a variety of novel healthy products. Public health practitioners may help address the issue of food waste by encouraging the use of "waste" such as okara through work with consumers and companies. These efforts may lead to increased food security and promote the health of humans and the environment.

Influence of okara with varying particle sizes on the gelling, rheological, and microstructural properties of glucono-δ-lactone-induced tofu

Influence of lyophilized okara with varying particle sizes (250-380, 150-180, 120-150, and < 75 μm) on the quality of glucono-δ-lactone-induced tofu was investigated. Adding okara significantly (p < 0.05) improved the yield, water-holding capacity, cooking loss, and nutritional value of the conventional tofu. The gel strength and sensory score of the okara-added tofu (OAT) increased with the decreasing of the particle size of okara, and these quality attributes of the OAT were better than those of the conventional tofu, except for the OAT with 250-380 μm okara. The microstructural profile of the OAT with reduced okara particle size was similar to that of the conventional tofu. Theoretically, the addition of okara mainly impacted the interactions among denatured proteins via disulfide bonding and hydrophobic interactions and the sizes of insoluble solid and oil droplet in soymilk, thereby affecting the formation of the gel network and finally the edible quality of tofu. In conclusion, the addition of okara with appropriate particle sizes can remarkably improve the processing quality and nutritional value of tofu, which is beneficial to the reasonable exploration of okara for the producers of soybean products.

Valorisation of By-Products from Soybean (Glycine max (L.) Merr.) Processing

In recent years, increased awareness of the health benefits associated with consuming soy-based foods, knowledge of milk-related allergies and a move towards more sustainable food production have led to an increase in the number of available soy-based products. The biggest producers in the world, the USA, South America and China, are from the Pacific region. This enormous production is accompanied by the accumulation of related by-products, in particular, a substance that is known as okara. Okara is a paste that is rich in fibre (50%), protein (25%), fat (10%), vitamins and trace elements. Its proper use would lead to economic advantages and a reduction in the potential for polluting the environment. Its high fibre content and low production costs mean that it could also be used as a dietary supplement to prevent diabetes, obesity and hyperlipidaemia. Chemical or enzymatic treatment, fermentation, extrusion, high pressure and micronisation can all increase the soluble fibre content, and thus improve nutritional quality and processing properties. However, the product also degrades rapidly due to its high moisture content (70-80%), which makes it difficult to handle and expensive to dry by conventional means. The aim of this paper is therefore to thoroughly study the existing literature on this subject in order to develop a general protocol for okara exploitation and valorisation. A cost/benefit analysis could drive the design of eco-friendly, sustainable protocols for the preparation of high-value nutritional products.

Repressive effects of red bean, Phaseolus angularis, extracts on obesity of mouse induced with high-fat diet via downregulation of adipocyte differentiation and modulating lipid metabolism

Obesity is generally caused by quantitative changes in adipocyte differentiation and fat metabolism. Only a few studies have been determined the effect of red beans extract on obesity and plasma cholesterol concentration. We have been studied the functional activities of red-bean extracts including anti-oxidative effect against DNA and cell damages. Histological study including micro CT analysis showed that the accumulation of fat in hepatocytes and intestines was significantly decreased in red bean extract treated group. In addition, plasma cholesterol and triglyceride levels were decreased in blood samples. In addition, it was confirmed that the red bean extract inhibited the expression of PPARγ, Fabp4 and RETN genes, which regulate total adipocyte differentiation and lipid metabolism. Red bean extract inhibits the expressions of transcription factors associated with adipocyte differentiation in a dose-dependent manner, thereby inhibiting fat accumulation and decreasing blood lipid levels in obese mice induced by high fat diet.

Effects of Tempeh Fermentation with Lactobacillus plantarum and Rhizopus oligosporus on Streptozotocin-Induced Type II Diabetes Mellitus in Rats

The increased consumption of high fat-containing foods has been linked to the prevalence of obesity and abnormal metabolic syndromes. Rhizopus oligosporus, a fungus in the family Mucoraceae, is widely used as a starter for homemade tempeh. Although R. oligosporus can prevent the growth of other microorganisms, it grows well with lactic acid bacteria (LAB). Lactobacillus plantarum can produce β-glucosidase, which catalyzes the hydrolysis of glucoside isoflavones into aglycones (with greater bioavailability). Therefore, the development of a soybean-based functional food by the co-inoculation of R. oligosporus and L. plantarum is a promising approach to increase the bioactivity of tempeh. In this study, the ameliorative effect of L. plantarum in soy tempeh on abnormal carbohydrate metabolism in high-fat diet (HFD)-induced hyperglycemic rats was evaluated. The co-incubation of L. plantarum with R. oligosporus during soy tempeh fermentation reduced the homeostatic model assessment of insulin resistance, HbA1c, serum glucose, total cholesterol, triglyceride, free fatty acid, insulin, and low-density lipoprotein contents, and significantly increased the high-density lipoprotein content in HFD rats. It also increased the LAB counts, as well as the bile acid, cholesterol, triglyceride, and short-chain fatty acid contents in the feces of HFD rats. Our results suggested that the modulation of serum glucose and lipid levels by LAB occurs via alterations in the internal microbiota, leading to the inhibition of cholesterol synthesis and promotion of lipolysis. Tempeh, which was produced with both L. plantarum and R. oligosporus, might be a beneficial dietary supplement for individuals with abnormal carbohydrate metabolism.

Potential fat-lowering and prebiotic effects of enzymatically treated okara in high-cholesterol-fed Wistar rats

This study evaluates the effect of the lipid profile on serum, liver and faeces, and the potential prebiotic effect of diets supplemented with enzymatically treated okara (okara(ET)) in high-cholesterol fed Wistar rats. Triglyceride levels were significantly reduced in the serum (p < 0.01) and liver (p < 0.01) of okara(ET) treated rats. Total lipids, triglycerides and bile acids were significantly higher (p < 0.001) in the faeces of rats fed the okara(ET) diet. The pH of faecal contents from treated okara(ET) rats was lower (p < 0.001), probably due to the significantly higher (p < 0.001) production of short-chain fatty acids (SCFA). Okara(ET), therefore, reduced triglycerides in serum and liver, and increased the excretion of total lipids, triglycerides and bile acids, improving the lipid profile in rats fed with high-cholesterol diets. Okara(ET) fibre can improve intestinal transit by increasing faecal bulk. The decreased pH and increased SCFA production indicated that okara(ET) fibre fermentation occurred, suggesting a potential prebiotic effect.

Okara, a soybean by-product, prevents high fat diet-induced obesity and improves serum lipid profiles in C57BL/6J mice

This study aimed to validate the anti-obesity effect of okara, a soyfood byproduct, in diet induced obese mice. Thirty two C57BL/6J male 4 week old mice were divided into four dietary groups (n=8) fed either normal diet (ND), high fat diet (HD), HD with 10% okara (OL), or HD with 20% okara (OH) for 12 weeks. Body weight gain and epididymal fat weight of OL and OH group were significantly lower than HD group. Similarly, the serum and hepatic lipid profiles in OH were significantly lower than HD group. The fecal triacylglycerol and TC levels in OL and OH increased compared to HD. Also, the expression of PPAR-α was higher in OH than HD group; PPAR-γ and FAS levels were lower in OH compared to HD. In this study, okara consumption appears to protect mice against diet induced obesity (DIO) and metabolic dysregulation related to obesity.

Production and evaluation of breakfast cereals from blends of acha and fermented soybean paste (okara)

Breakfast cereals was formulated from blends of acha and fermented okara (soybean residue). Acha grains were cleaned, winnowed, washed, dried (at 50 °C for 4 h) and milled into flour. Okara was processed from soybean seed through the stepwise procedure of cleaning, soaking, washing, milling and sieving. The residue was divided into five portions, fermented differently for 0, 12, 24, 36, and 48 h and then dried at 50 °C for 6 h. Acha flour (UFAC) was milled and blended at 50, 60, 70, 80, 90, 100 % ratio with milled okara flour. Functional properties (bulk density, water absorption capacity, swelling capacity, wettability, viscosity and particle size distribution, microbial load, and proximate composition were carried out on the individual flour samples. The blended flours were conditioned, partially heat treated (for 10 min), aged (4 °C for 6 h), cut, toasted (120 °C for 1 h), cooled and packaged. The different toasted breakfast cereals, TBFC, were subjected to sensory evaluation, proximate composition, micronutrient composition (vitamin A, B1, B2, B3, calcium, iron, phosphorus, and zinc) and microbial analyses (mould count and total viable count). The proximate composition of the unfermented okara (UFOK) and fermented okara (FEOK 1, 2, 3, and 4 fermented at 12, 24, 36, 48 h respectively) flour samples showed that fermentation increased moisture from 4.71 ± 0.06 to 6.11 ± 0.05, crude fibre from 36.62 ± 0.01 to 46.18 ± 0.55, and carbohydrate from 2.50 ± 0.18 to 2.71 ± 0.34 contents. There was a decrease in the fat content from 16.29 ± 0.04 to 13.27 ± 0.22, ash from 1.41 ± 0.17 to 6.36 ± 0.17 and crude protein from 30.32 ± 0.21 to 33.53 ± 0.11 contents. From the sensory evaluation, the result showed that 70:30 acha-unfermented okara TBFC, FEOK 1D 60:40 acha-12 h FEOK TBFC, 70:30 acha-24 h FEOK TBFC, 50:50 acha-36 h FEOK TBFC, and 70:30 acha-48 h FEOK TBFC had the best overall acceptability for the different fermentation times. The functional properties, proximate and sensory evaluation were the basis for selection of the best products which were UFAC (control), UFOK C (70:30 acha UFOK TBFC) and FEOK 4C (70:30 acha 48 h FEOK TBFC) which were further subjected to proximate, micronutrient, and microbial analyses. There was an increase in the protein, fat, ash, crude fibre content whereas the moisture and carbohydrate contents decreased. A considerable decrease was found in vitamin A and B1 contents of the products, whereas vitamin B2 and B3 increased. Also the mineral contents of all the products were improved as indicated in the increase in ash content.

Nutritional recovery with okara diet prevented hypercholesterolemia, hepatic steatosis and glucose intolerance

We assessed the biological value of an okara diet and its effects on the hormonal and metabolic profile of rats submitted to protein restriction during intra-uterine life and lactation and recovered after weaning. Male rats from mothers fed either 17% or 6% protein during pregnancy and lactation were maintained on 17% casein (CC, LC), 17% okara (CO, LO) or 6% casein (LL) diets over 60 d. The nutritional quality of the okara protein was similar to that of casein. The okara diet was effective in the nutritional recovery of rats in growing that were malnourished in early life. Furthermore, the okara diet reversed the hypercholesterolemia and the hepatic steatosis observed in the malnutrition and prevented glucose intolerance in an animal model prone to diabetes mellitus.

Soy fiber improves weight loss and lipid profile in overweight and obese adults: a randomized controlled trial

SCOPE

Studies have suggested that food rich in dietary fiber may facilitate body weight loss, lower total and LDL-cholesterol levels, and reduce body fat. This study examined the effects of soy fiber (SF) on body weight, body composition, and blood lipids in overweight and obese participants.

METHODS AND RESULTS

Thirty-nine overweight and obese college adults (19-39 years of age) were randomly assigned to consume control biscuits or biscuits supplemented with SF for their breakfast for 12 wk (approximately 100 g/day). There were significant differences in changes on body weight, BMI, and LDL-cholesterol (LDL-C) between the two groups after 12-wk intervention (p < 0.05). The changes of body weight, BMI, waist circumference, diastolic blood pressure, serum levels of total cholesterol, LDL-C, and glucose, body fat, and trunk fat of participants in SF group were observed significantly after 12 wk.

CONCLUSION

SF had favorable effects on body weight, BMI, and fasting LDL-C levels in overweight and obese adults. These effects may be beneficial in antiobesity and the improvement of hyperlipidemia and hypertension (ClinicalTrials.gov registration number-NCT01802840).

Bioactive proteins and energy value of okara as a byproduct in hydrothermal processing of soy milk

The nutritional properties of raw okara obtained as a byproduct from six soybean varieties during hydrothermal cooking (HTC) of soy milk were assessed. The composition and residual activity (rTIA) of trypsin inhibitors (TIs), contents of lectin, proteins, fats, and carbohydrates, and energy values (EV) were correlated with the respective physicochemical properties of soybean and okara. Kunitz (KTI) and Bowman-Birk (BBI) TIs both comprised okara rTIA. TIs content was higher in okara (5.19-14.40%) than in soybean (3.10-12.17%), which additionally enriched okara by cysteine. Contents of KTI (r = 1.00;p < 0.05) and BBI (r = 0.89;p < 0.05) as well as BBI monomeric (r = 0.89;p < 0.05) and polymeric forms (r = 0.95;p < 0.05) in okara and in soybean were strongly correlated. Low urease index activity indicated that okara was heated adequately to inactivate antinutritional factors. The proximate composition of raw okara, advantageous rTIA, and a very low EV (2.74-3.78 kJ/g) qualify this byproduct for potential application in food preparation as a functional ingredient in dietary products.

Decrease of Obesity by Allantoin via Imidazoline I 1 -Receptor Activation in High Fat Diet-Fed Mice

The activation of the imidazoline I₁-receptor (I₁R) is known to regulate appetite. Allantoin, an active ingredient in the yam, has been reported to improve lipid metabolism in high fat diet- (HFD-)fed mice. However, the effect of allantoin on obesity remains unclear. In the present study, we investigated the effects of allantoin on HFD-induced obesity. The chronic administration of allantoin to HFD-fed mice for 8 weeks significantly decreased their body weight, and this effect was reversed by efaroxan at a dose sufficient to block I₁R. The epididymal white adipose tissue (eWAT) cell size and weight in HFD-fed mice were also decreased by allantoin via the activation of I₁R. In addition, allantoin significantly decreased the energy intake of HFD-fed mice, and this reduction was associated with a decrease in the NPY levels in the brain. However, no inhibitory effect of allantoin on energy intake was observed in db/db mice. Moreover, allantoin lowered HFD-induced hyperleptinemia, and this activity was abolished by I₁R blockade with efaroxan. Taken together, these data suggest that allantoin can ameliorate energy intake and eWAT accumulation by activating I₁R to improve HFD-induced obesity.

Health-promoting effects of a dietary fiber concentrate from the soybean byproduct okara in rats

Okara (a byproduct of the soy milk industry) is rich in proteins (24.5-37.5 g/100 g of dry matter (dm)), lipids (9.3-22.3 g/100 g of dm), and dietary fiber (DF) (14.5-55.4 g/100 g of dm). It also contains isoflavones (0.14 g/100 g of dm). In the present study we fed female healthy Wistar rats either a standard rat diet or a supplemented 10% DF-rich okara (DFRO) diet for 4 weeks, and then we assessed several health parameters in the serum and the cecum compartments. In comparison to the control group, rats fed DFRO showed a significant decrease in weight gain (5.00 +/- 1.22 g vs 2.00 +/- 1.46 g, P < 0.03, during week 4) and in total cholesterol (65 +/- 8 mg/dL vs 51 +/- 5 mg/dL, P < 0.05) and a significantly increased antioxidant status (36.71 +/- 15.31 micromol of Trolox equivalents (TEs)/g vs 69.75 +/- 16.11 micromol of TEs/g, P < 0.0003) and butyrogenic effect (39.37%, P < 0.003) in the cecum. In addition, a significant enhancement in the apparent absorption (41.89 +/- 1.64% vs 47.02 +/- 2.51%, P < 0.004) and in the true retention (41.62 +/- 1.60% vs 46.68 +/- 2.55%, P < 0.005) of calcium was appreciated. In summary, these findings show for the first time that a concentrate DF from a soybean byproduct protects the gut environment in terms of antioxidant status and prebiotic effect. These results may highlight the development of an innovative soybean byproduct rich in DF which could be useful as a functional ingredient with health-promoting attributes.