Enzymatic extractability of soybean meal proteins and carbohydrates: heat and humidity effects

To study the incomplete enzymatic extractability of proteins and carbohydrates of thermally treated soybean meals, one unheated and three heat-treated soybean meals were produced. To obtain truly enzyme-resistant material, the meals were extracted by a repeated hydrolysis procedure using excessive concentrations of different combinations of commercial protease and carbohydrase preparations. The water extractability of protein from the different meals varied considerably (13-67%). For all soybean meals, enzymatic treatment extracted most of the original protein (89-94%). Carbohydrase preparations did not improve protein extraction. High-humidity heat treatment led to a more effective enzymatic extraction, which seemed to correlate with the extent of protein denaturation. Results with purified proteins indicated that the soybean meal matrix affects the enzymatic extraction of protein from the meals. Interactions between protein and other components (e.g., cellulose) may explain the incomplete enzymatic extractability of protein from the meals.     

Formation of a seed germination promoter from carbohydrates and amino acids

The ability of plant-derived smoke to act as a germination cue in many species has led to widespread interest in this aspect of seed biology. Recently, 3-methyl-2H-furo[2,3-c]pyran-2-one was identified as the main germination cue from smoke. Here, we report on the formation of this compound from reactions of sugars with amino acids. Heating proteins or amino acids with sugars at 180 degrees C for 30 min produces water soluble extracts that promote germination. High-performance liquid chromatography indicated that the active compound(s) derived from these reactions coeluted with the active fraction from a smoke solution. Gas chromatography-mass spectroscopy showed that the active constituent is identical to the germination cue from plant-derived smoke. The results presented in this paper provide evidence for the formation of the major germination cue found in smoke from ubiquitously occurring organic compounds.     

How proteins bind carbohydrates: lessons from legume lectins

The pioneering studies of Irvin Liener on soybean agglutinin (SBA) in the early 1950s served as the starting point of our involvement in lectin research during the past four decades. Initially we characterized SBA extensively as a glycoprotein and showed that its covalently linked glycan is an oligomannoside commonly present in animal glycoproteins. We have also introduced the use of the lectin to the study of normal and malignant cells and to the purging of bone marrow for transplantation. Our recent work focuses on the combining site of Erythrina corallodendron lectin, closely related to SBA. In this legume lectin, as in essentially all other members of the same protein family, irrespective of their sugar specificity, interactions with a constellation of three invariant residues (aspartic acid, asparagine, and an aromatic residue) are essential for ligand binding. Lectins from other families, whether of plants or animals, also combine with carbohydrates by H-bonds and hydrophobic interactions, but the amino acids involved may differ even if the specificity of the lectins is the same. Therefore, nature finds diverse solutions for the design of binding sites for structurally similar ligands, such as mono- or oligosaccharides. This diversity strongly suggests that lectins are products of convergent evolution.     

Production of the seed germination stimulant karrikinolide from combustion of simple carbohydrates

The naturally occurring seed germination stimulant karrikinolide is formed from the combustion of plant material including cellulose. It has previously been reported that combustion of simple carbohydrates such as d-glucose does not produce extracts containing karrikinolide. Moreover, it was reported that extracts with germination-promoting ability could be obtained only by combustion of simple carbohydrates in the presence of amino acids such as l-glycine. By employing a (13)C-labeled karrikinolide to physically quantify natural karrikinolide, we now show that it is produced from combustion of simple carbohydrates in similar amounts regardless of whether l-glycine is present or not. The addition of l-glycine appears to be beneficial in reducing the inhibitory effect of smoke extracts and provides a greater concentration range for effective germination-promoting activity.     

Characterization of methanol-soluble and methanol-insoluble proteins from developing peanut seed

The 85% methanol-soluble proteins are known to specifically contribute to the production of flavor of roasted peanut. To determine the nature of the 85% methanol-soluble proteins, they were isolated from the peanut seed, and the 85% methanol-soluble (MS) and 85% methanol-insoluble (MIS) fractions were characterized using polyacrylamide gel electrophoresis (PAGE) and capillary electrophoresis. The results showed that the 85% MS fraction contained lower amounts (9-10%) of protein than the MIS fraction (15-33%). Protein content of the MIS fraction increased more significantly during seed maturation than it did in the MS fraction. Unlike the protein, free amino acids and soluble sugars levels of the MS fraction decreased significantly during seed maturation. The 85% MS fraction contained predominantly low molecular weight (<20 kDa) proteins/polypeptides, whereas the MIS fraction contained a mixture of polypeptides with molecular weight between 14 kDa and 90 kDa. SDS-PAGE showed no major changes in the polypeptide composition of the MS fraction during seed maturation. Capillary electrophoretic analysis revealed major qualitative and quantitative changes in the protein and polypeptide composition of the MS and MIS fractions during seed maturation. Fatty acid analysis of these fractions indicated that the MS fraction is lipoprotein in nature and rich in oleic and linoleic acids.     

乙醇浸提紫苏籽压榨饼中油脂的工艺

为探讨乙醇作为植物油浸提溶剂的可行性,对乙醇溶液浸提紫苏籽低温压榨饼的工艺进行了研究。在浸提温度78℃下,采用单因素试验考察了浸提次数、料液比、乙醇浓度等因素对浸提粕中的残油率、蛋白质、单宁及植酸含量的影响。通过正交试验获得优化的工艺条件为:浸提次数为6次,料液比1︰2.5,乙醇浓度90%。在该工艺条件下,所获得的紫苏浸提粕中残油率为0.46%,蛋白质含量为50.5%(N×6.25,干基),单宁含量为1.7%,植酸含量为6.01%。当浸提所获混合油中油含量超过1%时,将混合油冷却至5℃下24h可观察到分相现象,其中轻相含油量在3%以下,重相含油量在90%以上,有利于溶剂回收。因此,将乙醇溶液作为植物油脂浸提溶剂有很大的潜力,但还需开展进一步的研究以推进该溶剂的工业应用。     

水酶法提取大豆油脂的中试研究

为了提高水酶法油脂提取率,该文进行水酶法提取大豆油脂的中试和循环酶解试验,验证小试和扩大试验的酶解和破乳参数对中试油脂提取率的影响,并研究循环酶解过程中循环次数及酶添加量对油脂提取率影响和中试工艺中大豆油脂的品质。以大豆为原料,由水酶法提取大豆油的中试得出:脱皮大豆比未脱皮大豆有助于提高油脂提取率和破乳率(P0.05,油脂提取率:脱皮61.85%,未脱皮56.91%;破乳率:脱皮92.01%,未脱皮90.42%)。通过主成分分析可知:大豆油脂的质量分数、离心后游离油和乳状液的质量分数、蛋白质的质量分数和乳状液中水分都是影响油脂提取率的关键因素。采用中试工艺1(1次提取,2次离心,1次破乳)进行循环酶解,随着循环试验次数增加,油脂提取率逐渐增大,在第4次时达到最大值66.46%±0.28%。通过检测大豆油脂的特征值可知:水酶法提取的大豆油脂的酸值、过氧化值、磷含量显著低于溶剂浸提法(P0.05),说明水酶法提取的大豆油品质高于溶剂浸提法,并且除水分和挥发物质量分数外,其他指标均符合国家三级大豆油标准。研究结果为产业化推广提供了理论参考。     

超声辅助提取水不溶性大豆膳食纤维及其物理特性

为研究超声辅助提取对豆渣中水不溶性大豆膳食纤维提取效率及物理特性的影响,该文以超声波为辅助,在液料比、超声功率强度、超声温度和超声时间4个单因素试验的基础上,通过四元二次通用旋转组合设计试验优化超声辅助提取水不溶性大豆膳食纤维的工艺条件,并采用扫描电镜、红外光谱仪等对超声辅助、酸溶碱沉、酶解辅助提取所获得的水不溶性大豆膳食纤维产品进行了物理特性表征。优化试验结果表明,在液料比35 mL/g、超声功率强度600 W/g、超声温度50℃、间歇性超声处理累计时间50 min条件下水不溶性大豆膳食纤维提取率较高,达92.11%。物性分析结果显示,与酸溶碱沉、酶解辅助提取的水不溶性大豆膳食纤维相比,超声辅助提取的水不溶性大豆膳食纤维具有更高的持水力、溶胀力、结合水力和结合脂肪能力以及更丰富的空间网状结构。研究结果揭示,超声辅助提取法不仅能够提高豆渣中水不溶性大豆膳食纤维的提取率,而且对其加工性能有很好的改进作用。     

红松种子壳多酚物质的提取及抗氧化特性

该文选取超声波辅助提取法,采用单因素试验及响应面设计,研究了超声波提取时间、温度、乙醇浓度及料液比对红松种子壳中多酚类化合物提取的影响。并利用Fenton体系、1,1-二苯基-2-苦苯肼(DPPH·)体系及邻苯三酚体系测定其提取成分的抗氧化活性。结果表明,松壳中多酚成分提取的最佳工艺条件为:超声提取时间2.80h、料液比1∶26.36(g/mL)、乙醇浓度42.86%、提取温度80℃,多酚得率7.96mg/g。在此优化条件下,红松种子壳提取物对羟自由基(甲基紫法)、DPPH·自由基及超氧阴离子均具有较强清除作用,半数抑制浓度分别为6.67×10-4、2.34×10-2、3.97mg/mL。     

超声波辅助提取经膨化大豆粕中低聚糖工艺

该文在考察超声波功率、超声波辅助提取时间等单因素对大豆低聚糖得率影响的基础上,选取超声波辅助提取时间、液料比和乙醇浓度进行三因素三水平的响应曲面试验,以确定超声波辅助提取经挤压膨化大豆粕中低聚糖的最佳条件和数学模型.并以超声波辅助提取未挤压膨化大豆、挤压膨化未超声波辅助提取和未挤压膨化未超声波辅助提取的大豆中低聚糖得率作为对照,以确定挤压膨化技术和超声波辅助提取技术对大豆低聚糖提取的影响.超声波辅助提取大豆低聚糖的最佳条件为乙醇浓度为31.3%,超声波辅助提取时间为34min,液料比为20.4mL/g,得率为11.95%,与未挤压膨化未超声波辅助提取对照试验相比提高了50.31%.挤压膨化技术处理和超声波技术有利于大豆低聚糖的提取.     

超声波辅助提取黑豆皮色素工艺优化

为了优化超声波辅助提取黑豆皮色素的工艺条件,在单因素试验基础上,采用响应曲面法对影响黑豆皮色素提取效果的3个主要影响因素即超声功率、溶液pH值和液固比进行了优化,建立并分析了各因子与黑豆皮色素提取液吸光值关系的数学模型。结果表明：原料用量0.5 g,在超声功率为80 W、溶液pH值1.5、液固比30 mL/g时,黑豆皮色素提取效果较好,在此条件下色素的提取率达到95.6%。     

Accumulation of carbohydrates and proline in water-stressed soybean (Glycine max L.)

Abstract

A wide range of metabolites accumulates under water stress depending on certain metabolic alterations. For example, free amino acids, especially free proline, accumulate in response to water stress ((l)). Proline accumulation is closely connected with carbohydrate metabolism. Thus, a carbohydrate requirement for proline accumulation in water-stressed leaves has been reported (2, 3).     

Isolation and enzymatic digestion of body complex of soybean seed

The body complex of the soybean seed (BCSS) was isolated from the single cells (27.2%) by a sequential procedure of autoclaving with water, cellulase digestion for the primary cell wall, pectinase digestion for the secondary cell wall, and defatting with hexane washing. Its characteristics were then investigated. The defatted BCSS (DBCSS) consisted of protein (76.5%) and mannose-rich carbohydrates (3.2%). Screening of the food-processing protease for the digestion of DBCSS was carried out, and a kind of alkaline protease was selected. The inner protein of DBCSS was easily extracted with 0.1 M sodium carbonate buffer, pH 10, and the insoluble shell of the body complex (SDBCSS) was left. SDBCSS consisted of hydrophobic amino acid-rich protein. SDBCSS was easily digested by the selected alkaline protease. SDBCSS was dissolved by boiling with sodium dodecyl sulfate-mercaptoethanol, and it was found to consist of a protein of approximately 3 kDa. The high enzymatic digestion including the selected protease for soybean seed and defatted soybean meal was carried out; both were extracted and digested with a yield of >99.5%. The final indigestible residue was found as paired hexagonal and filamentous organs of the soybean cells.     

黑大豆种皮花色苷的提取及其抗氧化作用研究

以黑大豆皮为材料,采用二次回归正交旋转组合设计对其花色苷的提取工艺进行了优化研究。结果表明,最佳提取参数为温度60℃、时间1 h、乙醇浓度60％、料液比1∶40。对黑大豆种皮花色苷含量与总抗氧化能力之间的相关性分析表明,二者之间存在极显著的线性关系(P<0.01),且黑大豆种皮花色苷提取物表现出较强的清除OH·、O^{-₂·及有机自由基DPPH·的体外抗氧化作用,其清除能力是维生素C的1.6倍、2.2倍、1.4倍。}     

超声辅助双水相集成提取芒果核多酚工艺优化（英）

为了获得超声辅助双水相集成提取芒果核多酚的最佳条件,该文提出一种超声提取与丙醇-硫酸铵双水相分离体系集成提取芒果核多酚的新方法,利用5水平4因素的星点设计响应面方法研究提取条件对芒果核总多酚提取率的影响。当超声功率为400W、初始温度为45℃,获得的最佳条件是59.7%丙醇浓度,23.4%硫酸铵用量,27.3min超声提取时间和23.0mL/g的液固比,在该条件下,芒果核多酚提取率为6.67%,试验值与最佳预测值(6.82%)相符,超声辅助双水相集成法获得的提取物多酚含量高于常规超声提取法。试验结果说明利用超声辅助双水相集成的方法改善多酚提取是可行性。该研究可为芒果核的利用和植物多酚的提取技术提供参考。     

Fagopyritols, D-chiro-inositol, and other soluble carbohydrates in buckwheat seed milling fractions

Fagopyritols are mono-, di-, and trigalactosyl derivatives of D-chiro-inositol that accumulate in seeds of common buckwheat (Fagopyrum esculentum Moench) and may be important for seed maturation and as a dietary supplement. Fagopyritols and other soluble carbohydrates were assayed in mature groats and 11 milling fractions of common buckwheat seed. Because fagopyritols are in embryo and aleurone tissues, differences in fagopyritol concentrations reflect varying proportions of these tissues in each milling fraction. Bran milling fractions contained 6.4 g of total soluble carbohydrates per 100 g of dry weight, 55% of which was sucrose and 40% fagopyritols. Flour milling fractions had reduced fagopyritol concentration [0.7 g/100 g of dry weight total fagopyritols in the dark (Supreme) flour and 0.3 g/100 g in the light (Fancy) flours]. Fagopyritol B1 was 70% of total fagopyritols in all milling fractions. Fagopyritols were 40% of total soluble carbohydrates in groats of two cultivars of common buckwheat but 21% in groats of tartary buckwheat [Fagopyrum tataricum (L.) Gaertn.], probably a reflection of environment and genetics. A rhamnoglucoside present in tartary buckwheat was not detected in common buckwheat.     

大豆籽粒大小遗传调控研究现状

籽粒大小是大豆产量和外观品质的重要构成要素,具有巨大的经济价值,一直以来都是育种的主要目标之一。大豆籽粒大小由胚、胚乳和种皮发育共同协调决定。目前已报道的与大豆籽粒重相关的QTL位点309个,但大多位点尚未进行功能验证。已发现的与大豆籽粒大小相关的基因有17个,多数与母本种皮发育调控相关,其它与合子组织和植物激素调控途径相关。其中,发挥正向和负向调控作用的基因分别有12个和4个。在不影响大豆品质情况下,PP2C-1、Gm20OX和CYP78A等基因在植物个体发育过程中对籽粒大小的调节发挥关键作用,有望成为大豆分子设计育种中的优良靶点。本文重点从连锁分析和关联分析方法,介绍了已鉴定的与大豆籽粒大小相关的QTL及其位点,综述了大豆籽粒大小调控分子机制的研究进展,并根据现阶段的研究探讨了未来的研究热点和研究方向,以期为大豆籽粒分子调控机制全面解析和高产育种技术创新提供理论参考。     

基于高光谱图像处理的大豆品种识别(英文)

大豆组分(油,蛋白质,脂肪等)在不同的大豆品种间差异很大。对于提高大豆品质来说,大豆品种识别是一个关键因素。该文利用高光谱图像技术对不同的大豆品种进行识别。利用高光谱成像系统获取大豆样本1 000～2 500 nm范围的光谱反射数据;应用主成分分析法(PCA,principal component analysis)对获取到的光谱数据进行数据降维并去除冗余数据;在分类算法中将得分高的主成分值作为输入特征,通过PCA方法从每个特征图像中提取4个特征变量(能量、熵、惯性矩和相关性);对于具体特征提取,从16个特征变量中提取8个重要特征参数;根据选择的特征,应用神经网络方法构建分类器;训练精度精度达到97.50%,平均测试精度达到93.88%以上。结果表明,应用高光谱图像技术结合神将网络建模方法可以对大豆品种进行分类。     

油茶籽饼粕中甲醇提取物抑制黄曲霉菌效果及成分分析

为了明确油茶籽饼粕中对黄曲霉菌有抑制作用的活性物质。该研究开展了油茶籽饼粕不同溶剂提取物对黄曲霉菌菌丝生长及产毒的影响研究。选用80%甲醇作为溶剂对油茶籽粕进行提取,提取液依次利用乙酸乙酯、饱和正丁醇进行梯度萃取,得到乙酸乙酯萃取相、正丁醇萃取相和水相,正丁醇萃取相对黄曲霉菌有较好的抑制效果,100mg/mL浓度效果最好,抑菌圈直径为22.00 mm,菌丝干质量相比对照减少了42.88%,黄曲霉毒素未被检出,而乙酸乙酯萃取相和水相对黄曲霉菌的抑制效果较弱,甚至无抑菌效果。采用柱层析、超高效液相色谱串联三重四级杆飞行时间质谱法对正丁醇萃取相中的抑菌物质进行纯化鉴定,分离出了3种黄酮苷类化合物:1)山奈酚-3-O-[β-D-吡喃葡萄糖苷-(1→3)-O-α-L-吡喃鼠李糖-(1→6)-O-β-D-吡喃半乳糖苷];2)山奈酚-3-O-[2-O-β-D-吡喃木糖基-6-O-α-L-吡喃鼠李糖]-β-D-吡喃葡萄糖苷;3)山奈酚-3-O-(6-反式-对-香豆酰基)-β-D-吡喃葡萄糖基-(1→3)-O-α-L-吡喃鼠李糖-(1→6)-O-β-D-吡喃半乳糖苷。以上研究结果为黄曲霉菌天然抑菌剂的研究和开发提供了参考,也拓宽了油茶副产物的加工利用途径。