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Corn distillers dried grains with solubles (DDGS) are not nutritionally complete as a nonruminant ingredient owing to poor essential amino acid profile, and high fat and fiber contents. Coproducts of soybean enzyme‐assisted aqueous extraction process, skim (wastewater) and insoluble fiber (IF; solid residue), and/or enzymes (pectinase, cellulase, and acid protease; referred to as PCF) were evaluated as distillers dried grains (DDG) nutritional quality enhancers in corn fermentation. Corn‐soy DDG had ~10% higher protein, ~3% lower fat, and ~2% lower fiber contents compared to corn DDG; fiber content was further reduced with PCF treatment (~4% total decrease). Concentrations of all essential amino acids in corn‐soy DDG showed at least a threefold increase, except for allo‐isoleucine and tryptophan, compared to corn DDG. Corn‐soy DDG had ~25% decrease in total fatty acid (TFA) and ~6% decrease in free fatty acid (FFA) contents compared to corn DDG; TFA and FFA contents further decreased with PCF treatment. Corn‐soy DDG had ~15%, 3%, and 1.7% lower hemicellulose, cellulose, and lignin contents, respectively, compared to corn DDG; hemicellulose content further decreased with PCF treatment. Mineral composition of corn‐soy DDG was in the recommended range, except Na and S were out of range by 0.79% and 0.74%, respectively. All results, except for Na and S, suggest strong potential of using skim and IF as DDG nutritional quality enhancers. [ABSTRACT FROM AUTHOR]

Insoluble fiber (IF) recovered from the enzyme-assisted aqueous extraction process (EAEP) of soybeans is a fraction rich in carbohydrates and proteins. It can be used to enhance ethanol production in an integrated corn-soy biorefinery, which combines EAEPwith traditional corn-based ethanol processing. The present study evaluated IF as a substrate for ethanol production. The effects of treatment of IF (soaking in aqueous ammonia (SAA), liquid hot water (LHW), and enzymatic hydrolysis), primarily simultaneous saccharification and co-fermentation (SSCF), as well as scaling up (250 mL to 60 L) on ethanol production from IF alone or a corn and IF slurry were investigated. Enzymatic hydrolysis (pectinase, cellulase, and xylanase, each added at 5% soy solids during simultaneous saccharification and fermentation/SSCF) was the best treatment to maximize ethanol production from IF. Ethanol yield almost doubled when SSCF of IF was performed with Saccharomyces cerevisiae and Escherichia coli KO11. Addition of IF in dry-grind corn fermentation increased the ethanol production rate (~31%), but low ethanol tolerance of E. coli KO11 was a limiting factor for employing SSCF in combination corn and IF fermentation. Nonlinear Monod modeling accurately predicted the effect of ethanol concentration on E. coli KO11 growth kinetics by Hanes-Woolf linearization. Collectively, the results from this study suggest a potential of IF as a substrate, alone or in dry-grind corn fermentation, where it enhances the ethanol production rate. IF can be incorporated in the current bioethanol industry with no added capital investment, except enzymes. [ABSTRACT FROM AUTHOR]

The effectiveness of soaking in aqueous ammonia (SAA) as a pretreatment method for the conversion of soybean fiber to ethanol via simultaneous saccharification and fermentation (SSF) was investigated. Insoluble fiber is a co-product from oil and protein extraction using two-stage, countercurrent, enzyme-assisted, aqueous extraction processing of full-fat soybean flakes (FFSF) and extruded FFSF. The fiber fractions were soaked in 15 wt% aqueous ammonia at 1:10 solid-to-liquid ratio. The effects of operating variables, including treatment times (6, 12, and 24 h), treatment temperatures (60 and 80 °C), and cellulase loadings (15 and 60 FPU/g-glucan) on the degree of enzymatic hydrolysis were determined. The best SAA conditions were 80 °C for 12 h followed by an enzyme loading of 15 FPU/g-glucan, which produced a 152-mg/g glucose yield after 48 h of hydrolysis. This was 8.7 times the amount produced from the same fiber not pretreated with SAA. The glucose yield increased to 381 mg/g when fiber obtained from extruded FFSF was submitted to SAA. SAA (80 °C, 12 h) on extruded fiber subjected to SSF increased ethanol yield from 0.06 g of ethanol/g [40% of theoretical yield] (for non SAA pretreated fiber) to 0.25 g of ethanol/g [92% of theoretical yield]. The combination of extrusion and SAA was an efficient means for converting the fiber-rich soybean fraction into ethanol. [ABSTRACT FROM AUTHOR]

Abstract: High hydrostatic pressure was applied to hydrated soybeans (100–700MPa, 25°C) and soymilk (400–750MPa; 25 and 75°C) to assess its effect on isoflavone content, profile and water-extractability. Neither pressure level nor initial treatment temperature affected soymilk isoflavone content. However, combined pressure and mild thermal treatment modified the isoflavone distribution. At 75°C, the isoflavone profile shifted from malonylglucosides toward β-glucosides, which was correlated to the effect of adiabatic heating. When pressure was applied to the hydrated soybeans, the soymilk isoflavone concentration varied between 4.32 and 6.06μmol/g. The content of protein decreased and fat increased in soymilks prepared from pressurized soybeans with increasing pressure level. [Copyright &y& Elsevier]

BSTRACT: The influence of soybean-to-water ratio (1:6 and 1:8) and pH (6 and 7) on characteristics of soymilk treated by high pressure processing (HPP, 500 and 600 MPa, 10 min, 25 °C) or thermal treatment (95 °C for 30 min) was investigated. Changes in the soymilk appearance were observed only for the 1:6, pH 6 soymilk that underwent a sol formation after HPP treatment and was apparently more viscous after thermal treatment. These changes were reflected in the viscosity values of these soymilks, which were increased by a factor of 4.3 and 3.6, after HPP and thermal treatment, respectively. After HPP treatment at pH 7 at both 1:6 and 1:8 ratios, the viscosity of the soymilks was unchanged compared to the controls. HPP treatment significantly increased the emulsion stability for all soymilks tested except for the 1:6, pH 7 soymilk. Peptide profiles of thermal- and pressure-treated samples were not affected; however, aggregates were observed in the soluble protein fraction after thermal and pressure treatment. Surface free and total free sulfhydryl content, surface hydrophobicity, and solubility of the proteins were decreased after HPP and thermal treatment regardless the soybean-to-water ratios and pH values of the soymilk. [ABSTRACT FROM AUTHOR]

Integrated corn-soy fermentation, utilizing co-products of soybean enzyme-assisted aqueous extraction process (EAEP) of soybeans in corn fermentation, has shown potential for enhancing bioethanol production compared to corn only fermentation. To maximize economic returns, oil may be recovered. In the present study, the effect of skim and insoluble fiber, and oil extraction aids on ethanol yield, oil partition, and oil recovery, and quality of Distillers Dried Grains (DDG) was investigated. Two fiber hydrolyzing enzymes (pectinase and cellulase), an acid protease (Fermgen ® ), and a surfactant (Tween 80) were evaluated. Addition of skim, mixture of skim and insoluble fiber, or Fermgen ® to corn fermentation resulted in a ∼32 h decrease in fermentation time. Addition of soy co-products also resulted in ∼10–28% increase in oil partition in thin stillage with no additional enzyme or surfactant treatment. Addition of insoluble fiber alone resulted in ∼19% decrease in solids partition in thin stillage. Maximum free oil recovery, 22.5 ± 4.5%, was achieved from corn-insoluble fiber thin stillage with a combined treatment of enzymes (pectinase, cellulase, and Fermgen ® ) and surfactant (Tween 80). Maximum extractable oil recovery, 67 ± 3.2%, was achieved with the enzyme treatment alone. Corn-soy DDG has ∼11% higher protein, ∼2% lower fiber, and ∼2% lower fat contents compared to corn DDG. The fiber content was further reduced to ∼2% after enzyme treatment. This study demonstrates an efficient use of soy EAEP co-products and enzymes to maximize oil partition in thin stillage, and produce a high quality corn-soy DDG. [ABSTRACT FROM AUTHOR]

Characterization and destabilization of the emulsion formed during aqueous extraction of oil from soybean flour were investigated. This emulsion was collected as a cream layer and was subjected to various single and combined treatments, including thermal treatments and enzymatic treatments, aimed at recovery of free oil. The soybean oil emulsion formed during the aqueous extraction processing of full fat flour contains high molecular weight glycinin and ß-conglycinin proteins and smaller oleosin proteins, which form a multilayer interface. Heat treatment alone did not modify the free oil recovery but freeze--thaw treatment increased the oil yield from 3 to 22%. After enzymatic treatment of the emulsion, its mean droplet size changed from 5 to 14 µm and the oil recovery increased to 23%. This increase could be attributed to the removal (due to enzymatic hydrolysis) of large molecular weight polypeptides from the emulsion interface, resulting in partial emulsion destabilization. When enzymatic treatment was followed by a freeze--thaw step, the oil recovery increased to 46%. This result can be attributed to the thinner interfacial membrane after enzymatic hydrolysis, partial coalescence during freeze--thaw, and coalescence during centrifugation. Despite the reduction in emulsion stability achieved, additional demulsification approaches need to be pursued to obtain an acceptably high conversion to free oil. [ABSTRACT FROM AUTHOR]

Abstract: The effectiveness of several pretreatments [high-power ultrasound, sulfuric acid (H2SO4), sodium hydroxide (NaOH), and ammonium hydroxide (NH3OH)] to enhance glucose production from insoluble fractions recovered from enzyme-assisted aqueous extraction processing of extruded full-fat soybean flakes (FFSF) was investigated. Sonication of the insoluble fraction at 144μmpp (peak-to-peak) for 30 and 60s did not improve the saccharification yield. The solid fractions recovered after pretreatment with H2SO4 [1% (w/w), 90°C, 1.5h], NaOH [15% (w/w), 65°C, 17h], and NH3OH [15% (w/w), 65°C, 17h] showed significant lignin degradation, i.e., 81.9%, 71.2%, and 75.4%, respectively, when compared to the control (7.4%). NH3OH pretreatment resulted in the highest saccharification yield (63%) after 48h of enzymatic saccharification. A treatment combining the extraction and saccharification steps and applied directly to the extruded FFSF, where oil extraction yield and saccharification yield reached 98% and 43%, respectively, was identified. [Copyright &y& Elsevier]

Abstract: Soybean insoluble fractions recovered from aqueous extraction processing (AEP) and enzyme-assisted AEP (EAEP) of full-fat soybean flakes (FFSF) and extruded FFSF were evaluated as a feedstock for the production of fermentable sugars using enzymes. Among the four insoluble fractions (AEP FFSF, EAEP FFSF, AEP extruded FFSF and EAEP extruded FFSF), the composition analysis revealed that the one recovered from EAEP of extruded FFSF had the highest glucan content, 16% [dry basis (db)], as compared to about 10% (db) for the other fractions. Thirty-three percent of the initial glucan of the insoluble recovered from AEP and EAEP of FFSF were converted into glucose using 33 FPU of Accellerase 1000/g-glucan. This saccharification yield was increased to 44% with extruded fibers. The higher saccharification yield of 49% was obtained at 45°C, 1% glucan loading, and 101 FPU/g-glucan enzymes loading after 27h of hydrolysis. [ABSTRACT FROM AUTHOR]