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1.
Defatted sesame meal ( approximately 40-50% protein content) is very important as a protein source for human consumption due to the presence of sulfur-containing amino acids, mainly methionine. Sesame protein isolate (SPI) is produced from dehulled, defatted sesame meal and used as a starting material to produce protein hydrolysate by papain. Protein solubility at different pH values, emulsifying properties in terms of emulsion activity index (EAI) and emulsion stability index (ESI), foaming properties in terms of foam capacity (FC) and foam stability (FS), and molecular weight distribution of the SPI hydrolysates were investigated. Within 10 min of hydrolysis, the maximum cleavage of peptide bonds occurred as observed from the degree of hydrolysis. Protein hydrolysates have better functional properties than the original SPI. Significant increase in protein solubility, EAI, and ESI were observed. The greatest increase in solubility was observed between pH 5.0 and 7.0. The molecular weight of the hydrolysates was also reduced significantly during hydrolysis. These improved functional properties of different protein hydrolysates would make them useful products, especially in the food, pharmaceutical, and related industries.  相似文献   

2.
The effects of enzymatic deamidation by protein-glutaminase (PG) on the functional properties of soy protein isolate (SPI) were studied. Conditions for the deamidation were evaluated by means of response surface methodology (RSM). Optimal conditions based on achieving a high degree of deamidation (DD) with a concurrently low degree of hydrolysis (DH) were 44 °C, enzyme:substrate ratio (E/S) of 40 U/g protein and pH 7.0. Under optimal conditions, both DD and DH increased over time. SDS-PAGE results indicated that lower molecular mass subunits were produced with increasing DD. Far-UV circular dichroism spectra revealed that the α-helix structure decreased with higher DD, while the β-sheet structure increased until 15 min of deamidation (32.9% DD), but then decreased at higher DD. The solubility of deamidated SPI was enhanced under both acidic and neutral conditions. SPI with higher DD showed better emulsifying properties and greater foaming capacity than SPI, while foaming stability was decreased. It is possible to modify and potentially improve the functional properties of SPI by enzymatic deamidation using PG.  相似文献   

3.
为提高酸性条件下大豆分离蛋白(soy protein isolates,SPI)的乳化性能,该文研究了物理-酶联合改性对SPI(pH值为4)的乳化性能影响,通过对比确定了物理-酶联合改性,即超声波-酶复合改性和挤压膨化-酶复合改性两种改性方法在酸性条件下的乳化性能效果最好;并通过对改性后 SPI(pH 值为4)进行溶解性、游离巯基、二硫键、粒径、扫描电镜(scanning electron microscope,SEM)和激光共焦扫描显微镜(confocal laser scanning microscopy,CLSM)分析,从蛋白结构变化上进一步揭示了乳化性能提高现象的原因。结果表明:超声波联合植酸酶-酸性蛋白酶改性的 SPI (Uphy-aci-SPI)的乳化活性(emulsifying activity index,EAI)为0.53 m2/g,比未改性SPI(0.18 m2/g)显著提高了196%(P<0.05),乳化稳定性(emulsifying stability index,ESI)为17 min,比未改性SPI(13.5 min)显著提高了25.9%(P<0.05);挤压膨化联合菠萝蛋白酶改性的SPI(Ebro-SPI)的EAI为0.46 m2/g,比未改性SPI显著增加了155%(P<0.05),ESI为17 min,比未改性SPI显著增加了25.9%(P<0.05)。在pH值为4的条件下对物理-酶联合改性的SPI的性质分析发现,物理-酶联合改性的SPI与未改性SPI相比,物理-酶联合改性的SPI的溶解性显著增加(P<0.05);物理-酶联合改性的SPI的乳状液平均粒径减小,CLSM观察乳状液中油与蛋白溶液稳定共融,改善了油滴之间的空间排斥力。物理-酶联合改性的SPI游离巯基的含量显著增加(P<0.05),二硫键含量显著降低(P<0.05)。SEM观察物理-酶联合改性的SPI为结构松散、破碎均一的微观结构。由此可见,乳化性能的提高是通过深层改变蛋白的结构来实现的。该研究可为探索提高酸性条件下SPI的乳化性能的方法提供理论依据。  相似文献   

4.
The emulsifying ability, heat stability, and coalescence stability of oil-in-water emulsions prepared with whey protein of varied degrees of hydrolysis (DH), and at varied protein contents, was studied. Whey protein hydrolysates (WPH) with a DH of 4% and 10% had poorer emulsifying ability than non-hydrolyzed whey protein concentrate (WPC), but were more heat stable. Increasing DH between 10 and 27% improved emulsifying ability and further improved the heat stability of the emulsion droplets. Increasing DH from 27 to 35% led to a big decrease in both emulsifying ability and heat stability. The quiescent coalescence stability of WPH emulsions was relatively good up to a DH of 27%. Above DH 27% emulsions become highly unstable. It appears that two mechanisms of instability are at work here. At low DH heat-induced denaturation and aggregation occur. In the DH range of 4-20% heat stability increases as protein globular structure is disrupted. At a DH greater than 27% we see a change from a hydrolysis-induced increase in heat-stability to coalescence instability, with a resultant large increase in emulsion breakdown during heating.  相似文献   

5.
The antioxidant activity of pectic enzyme treated pectin (PET-pectin) prepared from citrus pectin by enzymatic hydrolysis and its potential use as a stabilizer and an antioxidant for soy protein isolate (SPI)-stabilized oil in water (O/W) emulsion were investigated. Trolox equivalent antioxidant capacity (TEAC) was found to be positively associated with molecular weight (M(w)) of PET-pectin and negatively associated with degree of esterification (DE) of PET-pectin. PET-pectin (1 kDa and 11.6% DE) prepared from citrus pectin after 24 h of hydrolysis by commercial pectic enzyme produced by Aspergillus niger expressed higher α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity, TEAC, and reducing power than untreated citrus pectin (353 kDa and 60% DE). The addition of PET-pectin could increase both emulsifying activity (EA) and emulsion stability (ES) of SPI-stabilized O/W emulsion. When the SPI-stabilized lipid droplet was coated with the mixture of PET-pectin and pectin, the EA and ES of the emulsion were improved more than they were when the lipid droplet was coated with either pectin or PET-pectin alone. The amount of secondary oxidation products (thiobarbituric acid reactive substances) produced in the emulsion prepared with the mixture of SPI and PET-pectin was less than the amount produced in the emulsion prepared with either SPI or SPI/pectin. These results suggest that PET-pectin has an emulsion-stabilizing effect and lipid oxidation inhibition ability on SPI-stabilized emulsion. Therefore, PET-pectin can be used as a stabilizer as well as an antioxidant in plant origin in SPI-stabilized O/W emulsion and thus prolong the shelf life of food emulsion.  相似文献   

6.
Rice endosperm protein was modified to enhance solubility and emulsifying properties by controlled enzymatic hydrolysis. The optimum degree of hydrolysis (DH) was determined for acid, neutral, and alkaline type proteases. Solubility and emulsifying properties of the hydrolysates were compared and correlated with DH and surface hydrophobicity. DH was positively associated with solubility of resulting protein hydrolysate regardless of the hydrolyzing enzyme, but enzyme specificity and DH interactively determined the emulsifying properties of the protein hydrolysate. The optimum DH was 6–10% for good emulsifying properties of rice protein, depending on enzyme specificity. High hydrophobic and sulfhydryl disulfide (SH-SS) interactions contributed to protein insolubility even at high DH. The exposure of buried hydrophobic regions of protein that accompanied high-temperature enzyme inactivation promoted aggregation and cross-linking of partially hydrolyzed proteins, thus decreasing the solubility and emulsifying properties of the resulting hydrolysate. Due to the highly insoluble nature of rice protein, surface hydrophobicity was not a reliable indicator for predicting protein solubility and emulsifying properties. Solubility and molecular flexibility are the essential factors in achieving good emulsifying properties of rice endosperm protein isolates.  相似文献   

7.
The amino acid composition and physicochemical and functional properties of hemp (Cannabis sativa L.) protein isolate (HPI) were evaluated and compared with those of soy protein isolate (SPI). Edestin, a kind of hexameric legumin, was the major protein component. HPI had similar or higher levels of essential amino acids (except lysine), in comparison to those amino acids of SPI. The essential amino acids in HPI (except lysine and sulfur-containing amino acids) are sufficient for the FAO/WHO suggested requirements for 2-5 year old children. The protein solubility (PS) of HPI was lower than that of SPI at pH less than 8.0 but similar at above pH 8.0. HPI contained much higher free sulfhydryl (SH) content than SPI. Differential scanning calorimetry analysis showed that HPI had only one endothermic peak with denaturation temperature (T(d)) of about 95.0 degrees C, attributed to the edestin component. The T(d) of the endotherm was nearly unaffected by 20-40 mM sodium dodecyl sulfate but significantly decreased by 20 mM dithiothreitol (P < 0.05). The emulsifying activity index, emulsion stability index, and water-holding capacity of HPI were much lower than those of SPI, and the fat adsorption capacity was similar. The data suggest that HPI can be used as a valuable source of nutrition for infants and children but has poor functional properties when compared with SPI. The poor functional properties of HPI have been largely attributed to the formation of covalent disulfide bonds between individual proteins and subsequent aggregation at neutral or acidic pH, due to its high free sulfhydryl content from sulfur-containing amino acids.  相似文献   

8.
Rice endosperm protein was prepared by alkali-extraction method and subsequently modified by controlled glycosylation (RPGlu, RPXG), deamidation (RPDA), and enzymatic hydrolysis by alcalase (RPAlc) methods. The RPGlu and RPXG were prepared by Maillard type glycosylation with D-glucose and xanthan gum, respectively. The glycosylation improved the emulsion activity (0.721) and stability (26.8 min) of the protein but did not show a substantial improvement in solubility (39.7%). The rice protein modified by controlled alkali-deamidation (RPDA) showed highest solubility (68%), emulsion activity (0.776), and emulsion stability (24 min) among the three protein modification methods evaluated in this study. The alcalase treatment to 1.8% DH (RPAlc) slightly improved solubility (33%), emulsion activity (0.468), and emulsion stability (17.5 min) compared with unmodified rice protein (RP), which had 18% solubility, 0.266 emulsion activity, and 14.7 min emulsion stability. The glycosylation and deamidation methods were more effective than the controlled enzymatic hydrolysis by alcalase in improving solubility and emulsifying properties of rice endosperm protein. Glycosylated and deamidated rice endosperm proteins can find application in enhancing emulsifying properties in suitable products.  相似文献   

9.
Physicochemical and functional properties of buckwheat protein product   总被引:14,自引:0,他引:14  
This study was conducted to compare the physicochemical and functional properties of buckwheat protein product (BWP), soy protein isolate (SPI), and casein. BWP was prepared from buckwheat flour by the method including alkaline extraction and isoelectric precipitation. The amino acid composition of BWP was very similar to that of buckwheat flour. The protein solubility (PS) of BWP was much greater than that of SPI at all pH levels (pH 2-10) but lower than that of casein at pH 7-10. The isoelectric point of BWP was around pH 4. The higher aromatic hydrophobicities (ARH) of BWP, SPI, and casein were obtained at lower pH levels (pH 2-3). The emulsifying stability (ES) of BWP was lower than those of SPI and casein at high pH levels (pH 7-10). At all pH levels, BWP formed a thin emulsion. Regression analysis showed that the ARH of BWP was significantly associated with the ES. Although the water holding capacity of BWP was quite lower than that of SPI, its fat absorption capacity was slightly higher than those of SPI and casein. These results indicated that the physicochemical properties of BWP were different from those of SPI or casein. Thus, BWP is a potential source of functional protein for possible food application.  相似文献   

10.
Brewers' spent grain (BSG) is the insoluble residue of barley malt resulting from the manufacture of wort. Although it is the main byproduct of the brewing industry, it has received little attention as a marketable commodity and is mainly used as animal feed. Our work focuses on one of the main constituents of BSG, i.e., the proteins. The lack of solubility of BSG proteins is one of the limitations for their more extensive use in food processing. We therefore aimed to generate BSG protein hydrolysates with improved technofunctional properties. BSG protein concentrate (BPC) was prepared by alkaline extraction of BSG and subsequent acid precipitation. BPC was enzymatically hydrolyzed in a pH-stat setup by several commercially available proteases (Alcalase, Flavourzyme, and Pepsin) for different times and/or with different enzyme concentrations in order to obtain hydrolysates with different degrees of hydrolysis (DH). Physicochemical properties, such as molecular weight (MW) distribution and hydrophobicity, as well as technofunctional properties, such as solubility, color, and emulsifying and foaming properties, were determined. Enzymatic hydrolysis of BPC improved emulsion and/or foam-forming properties. However, for the hydrolysates prepared with Alcalase and Pepsin, an increasing DH generally decreased emulsifying and foam-forming capacities. Moreover, the type of enzyme impacted the resulting technofunctional properties. Hydrolysates prepared with Flavourzyme showed good technofunctional properties, independent of the DH. Physicochemical characterization of the hydrolysates indicated the importance of protein fragments with relatively high MW (exceeding 14.5 k) and high surface hydrophobicity for favorable technofunctional properties.  相似文献   

11.
提高大豆蛋白冻融后乳化性改性工艺优化   总被引:4,自引:1,他引:3  
为了制备出经冷冻-融化后仍能保持较高乳化性的大豆蛋白,试验以葡聚糖为糖基化供体,采用湿法糖基化技术改性大豆蛋白。根据单因素试验的结果,建立了Box-Behnken模型对加工工艺进行优化,所得的模型拟合度高,切实可行,可用于实际分析和预测。利用响应面分析法探讨了蛋白浓度、蛋白与糖质量比、反应时间3因素对改性产物冻融前后乳化活性和乳化稳定性的影响,优化的工艺条件为:大豆分离蛋白(soybean protein isolate,SPI)质量浓度40 mg/mL,SPI与葡聚糖的质量比为1∶3,反应时间4 h。在此条件下得到的改性产物冻融稳定性显著(P0.05)高于未改性蛋白,冻融前后的乳化活性(emulsifying activity index,EAI)分别是空白对照样的1.687和1.780倍,乳化稳定性(emulsion stability index,ESI)分别是空白对照样的1.367和1.274倍。傅里叶红外光谱证明葡聚糖通过共价键接到大豆蛋白分子中,研究结果为制备冷冻食品加工专用大豆蛋白的产业化生产提供参考。  相似文献   

12.
Industrial proteins from agriculture of either animal or vegetable origin, including their peptide derivatives, are of great importance, from the qualitative and quantitative point of view, in food formulations (emulsions and foams). A fundamental understanding of the physical, chemical, and functional properties of these proteins is essential if the performance of proteins in foods is to be improved and if underutilized proteins, such as plant proteins (and their hydrolysates and peptides derivatives), are to be increasingly used in traditional and new processed food products (safe, high-quality, health foods with good nutritional value). In this contribution we have determined the main physicochemical characteristics (solubility, composition, and analysis of amino acids) of a sunflower protein isolate (SPI) and its hydrolysates with low (5.62%), medium (23.5%), and high (46.3%) degrees of hydrolysis. The hydrolysates were obtained by enzymatic treatment with Alcalase 2.4 L for DH 5.62 and 23.5% and with Alcalase 2.4 L and Flavorzyme 1000 MG sequentially for DH 46.3%. The protein concentration dependence on surface pressure (surface pressure isotherm), a measure of the surface activity of the products (SPI and its hydrolysates), was obtained by tensiometry. We have observed that the degree of hydrolysis has an effect on solubility, composition, and content of the amino acids of the SPI and its hydrolysates. The superficial activity and the adsorption efficiency were also affected by the degree of hydrolysis.  相似文献   

13.
Different deamidation conditions for the Z19 alpha-zein were studied in order to find the best conditions for the development of the emulsifying properties. Alkaline deamidation was chosen, and the effects on the peptide bond cleavage, secondary structure, emulsifying properties, and surface hydrophobicity were studied. The Z19 alpha-zein was deamidated by using 0.5 N NaOH containing 70% ethanol at 70 degrees C for 12 h. A deamidation degree (DD) of 60.6 +/- 0.5%, and a degree of hydrolysis (DH) of 5 +/- 0.5% were achieved. Analysis by far-UV circular dichroism showed that the denaturation was mainly promoted by the high temperature used during the incubation. The adequate balance between the DD and the DH results in an effective emulsifying property improvement for the Z19 alpha-zein. Thus, after the deamidation treatment, the surface hydrophobicity decreased from 9.5 x 104 +/- 6.8 x 103 to 46 x 104 +/- 2.1 x 103, and the emulsion stability increased from 18 +/- 0.7% to 80 +/- 4.7% since the oil globules stabilized by the modified protein were smaller (57.7 +/- 5.73 nm) and more resistant to coalescence than those present in the native protein emulsions (1488 +/- 3.92 nm).  相似文献   

14.
为了提高大豆蛋白冻融稳定性,研究了超声波辅助下大豆分离蛋白(soybean protein isolate,SPI)与葡聚糖(dextran,D)发生美拉德反应改性蛋白的方法,以乳化稳定性(emulsion stability index,ESI)和乳析指数(creaming index,CI)为响应值,建立了优化工艺的Box-Behnken模型。验证试验表明,模型具有重现性和可靠性,在SPI质量浓度40 mg/m L、超声温度80℃、比功率5 W/m L条件下,与未改性SPI相比,改性后SPI乳化稳定性提高了43.80%,经1、2、3次冻融循环后乳析指数分别降低了57.76%、75.33%、96.20%。接枝物制备的乳液经冻融循环后粒径维持在50~55μm。红外光谱分析接枝物在1 010 cm-1处的C-N共价键振动增强,说明SPI和葡聚糖是以共价键的方式结合。扫描电镜结果表明,改性后蛋白颗粒更加疏松,分子间聚集程度降低。研究结果为冷冻食品专用大豆分离蛋白的产业化生产提供了理论和技术指导。  相似文献   

15.
燕麦麸分离蛋白的酶解对其功能性质的影响   总被引:4,自引:3,他引:4  
为了改善燕麦蛋白的功能性质以扩大其在食品工业中的应用,该文以燕麦麸为原料制备了燕麦麸分离蛋白(OBPI),并利用胰蛋白酶对其进行水解,得到了3种不同水解度(4.1%、6.4%、8.3%)的酶解产物。SDS-PAGE分析结果表明OBPI中的主要蛋白成分是球蛋白,其经过胰蛋白酶处理后,球蛋白酸性亚基被部分水解而碱性亚基相对保持完整。胰蛋白酶水解显著改变了OBPI的功能性质。在所考察的水解度范围内,随着水解度的升高,酶解产物的溶解性、持水性、乳化活性及起泡能力等方面均逐渐增加;但持油性、乳化及泡沫稳定性有不同程度的降低。  相似文献   

16.
Solubility, foaming capacity/stability, water holding and fat absorption capacities, and emulsifying capacity/stability of a solubilized wheat protein isolate (SWPI) were compared with those of commercial protein, that is, sodium caseinate (NaCAS), dried egg white (DEW), nonfat dry milk (NFDM), and soy protein isolate (SPI). SWPI was highly soluble at pH 6.5-8.5. Foaming capacity of SWPI was superior to those of SPI, NFDM, and DEW, and its foaming stability was similar to those of the commercial proteins. Foaming properties of SWPI were greatly improved in the presence of 0.5% (w/v) CaCl(2). Water holding capacity of SWPI was greater than that of NaCAS, NFDM, and DEW, whereas its fat absorption capacity was comparable to that of SPI, NaCAS, and DEW. SWPI exhibited emulsifying properties similar to those of SPI. SWPI was incorporated at 5, 10, 15, or 20% into ice cream, chocolate chip cookies, banana nut muffins, and hamburger patties. Products containing <5% SWPI were acceptable to consumers.  相似文献   

17.
为提升大豆分离蛋白(soy protein isolate,SPI)的功能性质,该文引入大豆可溶性多糖(soybean soluble polysaccharides,SSPS),构建大豆分离蛋白-大豆可溶性多糖体系(SPI-SSPS),研究动态高压微射流(dynamic high-pressure microfluidization,DHPM)处理对SPI-SSPS功能特性的影响。分别采用0,60,100,140和180 MPa的 DHPM压力处理SPI-SSPS,探究不同压力对SPI-SSPS起泡特性、乳化特性、溶解性、粒度分布和表面疏水性的影响。结果表明,DHPM处理能提高SPI的溶解性和起泡特性,且SSPS的存在能显著提高DHPM对SPI功能性质的改善效果(P<0.05)。100和60 MPa的DHPM处理能使SPI-SSPS呈现较高的起泡能力和起泡稳定性,分别为未处理样品的1.2和2.4倍。140 MPa的DHPM处理使SPI-SSPS溶解性较强,为未处理样品的1.8倍。然而,DHPM处理会显著降低SPI-SSPS的乳化特性、粒径和表面疏水性(P<0.05)。随着处理压力的增加,SPI-SSPS的粒度和表面疏水性逐渐降低,在180MPa的DHPM处理下SPI-SSPS具有较小的粒径和较低的荧光强度。综上所述,DHPM结合SSPS改性技术可用于改善SPI的功能性质(如溶解性、起泡性),促进SPI在食品工业的应用。该文的研究结果可为SPI的功能性质改性提供参考。  相似文献   

18.
高场强超声-加热联用增强大豆分离蛋白冷凝胶凝胶特性   总被引:1,自引:1,他引:0  
为探究高场强超声技术对大豆分离蛋白葡萄糖酸内酯冷凝胶性的影响,该研究将高场强超声技术与加热处理联用,对大豆蛋白进行预处理后形成冷凝胶。采用质构仪、圆二色谱、荧光色谱、扫描电镜、电泳、粒度仪等多种表征手段,比较了2种高场强超声-加热联用工艺对大豆分离蛋白冷凝胶凝胶性的影响,并推测其作用机理。研究发现:与传统加热预处理相比,2种高场强超声-加热联用预处理都能够显著(P0.05)增强大豆分离蛋白冷凝胶的持水性和凝胶强度。工艺一(20 k Hz,400 W下先超声0、2、4、10 min后加热20 min)制备的冷凝胶的凝胶强度与持水性随超声时间的增加逐步增加(凝胶强度由(5.83±0.31)g增加到(46.37±1.15)g;持水性由42.04%±1.59%增加到81.74%±6.22%),而工艺二(先加热20 min后超声0、2、4、10 min)制备的冷凝胶的凝胶强度与持水性在较短超声时间内(4 min内)迅速增加(凝胶强度由(5.83±0.31)g增加到(37.57±2.57)g;持水性由42.03%±1.85%增加到79.31%±3.00%)。与工艺一相比,工艺二能够在较短超声时间内增强大豆分离蛋白冷凝胶性的机理可能在于:工艺二的处理方式,大豆蛋白经过热处理后充分展开、变性,使超声作用能在较短的时间内对大豆分离蛋白的二级结构和三级结构明显改变,暴露更多疏水基团,增加疏水环境和表面疏水性,增强蛋白在溶液中的溶解性,并增强大豆蛋白分子间的静电相互作用,从而形成致密、均一的微观凝胶结构,增加凝胶的持水性和凝胶强度。研究结果可为高场强超声-加热联用技术在大豆加工领域中的应用提供参考。  相似文献   

19.
We have quantified observed differences in the microstructure and rheology of creaming emulsions stabilized by protein and low molecular weight surfactants. In this study, we made two sets of emulsions from a single parent emulsion, which differed only in their interfacial composition (i.e., either protein or surfactant). The protein studied was whey protein isolate. The zeta potential of the surfactant-stabilized emulsion was controlled by mixing anionic (SDS) and nonionic (Brij 35) surfactants to match the zeta potential of the protein-stabilized emulsion. Despite this, ultrasonic creaming measurements and confocal microscopy showed that the structures within the cream layers were different between the two sets of emulsions. The protein-stabilized emulsions appeared to slow or arrest the packing within the cream, leading to a lower density network of emulsion droplets, whereas the surfactant emulsion droplets rearranged more quickly into a well-packed, concentrated cream layer. Rheological analysis of the creams showed that despite the protein-stabilized emulsions having a lower dispersed phase volume fraction, their elastic modulus was approximately 30 times greater than that of a comparable surfactant-stabilized emulsion. These differences were caused by the ability of the protein to form a highly viscoelastic interfacial network around the droplets which may include intermolecular covalent cross-links. At close range the adhesive nature of the interaction between the layers contributes to the microstructure and rheology of concentrated emulsions. This is the first time that such well-defined emulsion systems have been studied in detail both noninvasively to look at the impact on creaming and also invasively to look at the impact on bulk rheological properties.  相似文献   

20.
乙二醇-氯化铁预处理对棉秆酶水解效率的影响   总被引:1,自引:1,他引:0  
董倩  唐松  徐禄江  方真 《农业工程学报》2021,37(14):213-220
为提高棉秆的纤维素酶水解效率,该研究以乙二醇为预处理溶剂,氯化铁为催化剂对棉秆进行预处理,实现了棉秆木质素和半纤维素的有效去除,提高了酶水解效率。以木质素和半纤维素的去除率为指标,运用正交试验方法优化乙二醇-氯化铁预处理条件。结果表明,棉秆在90%乙二醇水溶液,0.1 mol/L氯化铁,固液比1∶15,160 ℃条件下处理20 min,木质素和半纤维素去除率分别为85.7%和88.9%。相较原料,预处理后棉秆酶解率提高了7.6倍,葡萄糖产率达到100%(基质浓度5%,酶载量8.3 FPU/g,水解72 h条件下)。通过结构表征发现乙二醇-氯化铁预处理使棉秆的比表面积增大,致密结构被破坏,有效提高了棉秆的纤维素酶可及性。  相似文献   

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