Kinetics of Trypsin Inhibitory Activity Loss in Heated Flour from Bean, Phaseolus vulgaris

The effect of temperature, time and moisture content on, trypsin inhibitory activity of bean flour was studied. Trypsin inhibitory activity loss followed first-order reaction kinetics and the rate of loss was greatly increased with increasing moisture content of flour from 2-55%. Activation energies for the first-order reaction constants were calculated and ranged between 13-27 Kcal/mole, showing a maximum value at 30% moisture content.     

Effect of Heat Treatment on Sorption Isotherms and Solubility of Flour and Protein Isolates from Bean Phaseolus vulgaris

The effect of heating at 50, 70 or 90°C and low moisture contents on water sorption behavior (above about 0.65 water activity) and nitrogen solubility of bean flour and protein isolates, was investigated. The results suggested that relative water sorption changes, in the range studied, may not be the most adequate indicators of nitrogen solubility changes in “dry”/“moist” heated protein products. This is so because heated samples may undergo very important changes in nitrogen solubility while having experienced relatively little modifications in water sorption capacity.     

Effect of Temperature and Moisture Content on the Kinetics of Trypsin Inhibitor Activity, Protein in vitro Digestibility and Nitrogen Solubility of Cowpea Flour

Samples of finely ground cowpea flour containing 7.5%, 19.4% and 25.5% moisture were heated in sealed tubes at 100° 125° and 150°C for periods of 0.5 to 120 min. First order rate constants for losses of trypsin inhibitor activity and nitrogen solubility ranged from 1 × 10^?2 to 18 min^?1 and from 4 × 10^?2 to 8 min^?1 respectively. In vitro protein digestibility (IVD) increased, then decreased with heating as described by sequential first order kinetics. Rate constants for increase of IVD varied from 0.13 to 12 min^?1, while for decrease in IVD the range was 5 × 10^?5 to 3 × 10^?2 min^?1. Activation energies and relationships between In k and water activity were computed.     

Thermal Effects on in vitro Protein Quality of Red Kidney Bean (Phaseolus vulgaris L.)

Significant thermal effects on in vitro protein quality of red kidney beans were observed. Beans autoclaved at 121°for 10 and 20 min, and common home-cooked beans had improved protein quality. Uncooked beans, and those autoclaved at 128°for 20 min and at 121°for 90 min had reduced protein quality compared to canned beans and those autoclaved at 110°for 20 min and at 121°for 40 and 60 min. Amino acid scores, essential amino acid index and available lysine (%), corrected for in vitro protein digestibility gave comparable results in evaluation of protein quality. Specific lysine, methionine, cysteine and other amino acid ratios overestimated protein quality.     

Protein quality of germinated Phaseolus vulgaris

Advantages of seed germination consist of an increase in the bioavailability of proteins as well as the change in the antinutritional factors which limit their utilization. Throughout this work, the effects of germination and cooking after germination on the protein in black and white beans (Phaseolus vulgaris) were evaluated. Antinutritional factors that affect the utilization of such protein were also assessed. The amounts of protein, available lysine, tannins, PER, and protein digestibility in vitro and apparent, of beans germinated and germinated-cooked were quantified. The germination significantly (p≤0.05) increased the content of proteins, inactived trypsin inhibitors, and raised the available lysine. Germination and cooking completely inactivated the trypsin inhibitors, which became lysine less available, decreased tannins, and increased protein digestibility and PER value. Differences between black and white beans were observed and attributed to variations in structure, composition, and varieties, among other factors. Cooking complements the effect of germination by improving the protein quality of P. vulgaris and increasing its bioavailability for the human consumption.     

绿豆粉及其蛋白质对面条品质影响的研究

通过在面粉中分别添加不同比例的绿豆粉(MBF)、绿豆蛋白(MBP),研究其对面粉粉质特性、鲜面条蒸煮品质和感官品评的影响.结果表明:MBF和MBP均可提高面粉的营养价值;MBF含量在10%范围内对面粉粉质特性、蒸煮特性的影响不大,含量在10%时感官品评显示总分最高;MBP含量在4%范围内,面粉粉质特性提高,鲜面条的蒸煮吸水率下降,干物质损失率变化不大,含量在4%时感官评分最高.     

Wheat Germ Protein Flour Solubility and Water Retention

The effects of pH and temperature on water retention (WR), protein solubility (PS), and total solubility (TS) of defatted wheat germ protein flour (WGPF) were studied in a model system. PS of WGPF was compared with those of corn germ protein flour (CGPF), soy flour (SF), nonfat dried milk (NFDM), and egg white powder (EWP) at 1–8%. WR increased with increase in pH from 4 to 8. Maximum WR occurred at 70°C, and slight variations were observed between 5 and 30°C. PS and TS increased with increases in pH and temperature. PS of proteins was in the order of NFDM > EWP > SF > CGPF=WGPF. The results showed the potential for usage of WGPF in comminuted meats, beef patties, breads, cakes, and cookies.     

微射流处理对红豆分离蛋白结构及功能特性的影响

采用高压微射流纳米均质机处理红豆分离蛋白,运用溶解度、比浊法、圆二色光谱法探讨了多次微射流处理对红豆分离蛋白构象和功能特性的影响规律.微射流处理诱导不溶性蛋白聚合物解聚,增加了蛋白质的溶解度,改善了蛋白的乳化活性指数;圆二色光谱分析表明,红豆蛋白的二级结构组成:α-螺旋结构为6.2％,β-类结构为59.3％,无规则卷曲...     

菜豆属豆类蛋白酶促凝胶性能比较研究

研究比较芸豆(KPI)、红豆(RPI)和绿豆(MPI)3 种菜豆属类分离蛋白和大豆分离蛋白(SPI)在微生物转谷氨酰胺酶(MTGase)作用下的凝胶性能,并对其凝胶形成机理加以分析。SDS-PAGE 电泳和哈克流变分析结果表明：菜豆类分离蛋白是MTGase 的良好作用底物,初始成胶所需时间：KPI ＜ MPI ＜ SPI ＜ RPI。而酶反应后的凝胶G′值：RPI ＞ MPI ＞ KPI ＞ SPI,即KPI 形成凝胶最快,而RPI 最终成胶的强度最大;通过对不同溶剂下胶体溶解性的比较发现,除了酶共价交联外,静电相互作用,疏水作用及氢键都是形成凝胶的主要作用力,由于菜豆属类蛋白主要富含7S 球蛋白(不含二硫键),二硫键对其凝胶的稳定性作用不如SPI 明显。     

糖苷化对芸豆分离蛋白功能性质的影响

本研究通过干热接枝反应制备糖苷化芸豆蛋白,探讨了不同的蛋白与糖摩尔比对糖基化反应和芸豆蛋白物化性质及功能特性的影响.研究结果表明:适度的蛋白与糖摩尔比有利于糖苷化反应,蛋白与乳糖摩尔比为1:30时,糖苷化度是48%,而蛋白与乳糖摩尔比是1:100时,糖苷化度仅为14%.干热处理诱导芸豆蛋白质的变性和聚集,这一点在蛋白的溶解度和排阻色谱分析中得到证实,表现为降低蛋白质溶解度(pH 2～10)和排阻色谱峰的总积分面积(pn 7.0).糖基化反应可以抑制干热过程中蛋白质的变性和聚集行为,在中性偏碱性以及极端酸性(pH 2～3)条件下,糖苷化蛋白具有较高的蛋白溶解度(相对于干热处理的芸豆蛋白).在较高糖苷化程度条件下(蛋白质与乳糖摩尔比为1:30),糖苷化显著改善芸豆蛋白质的溶解度(pH 4～6).此外,乳糖与蛋白质共价连结,这一点在排阻色谱分析中的得到证实.     

Kinetics of Frozen Stored Green Bean (Phaseolus vulgaris L.) Quality Changes: Texture, Vitamin C, Reducing Sugars, and Starch

ABSTRACT: Texture, vitamin C, reducing sugars, and starch quality changes of frozen green beans ( Phaseolus vulgaris L.) were studied for 250 d at storage temperatures of−7,−15, and−30 °C. All studied parameters suffered significant changes during frozen storage. Texture loss was described by a fractional conversion model, while ascorbic acid and starch evolution were successfully modeled with first-order reaction kinetics. Dehydro-ascorbic acid (DHAA) degraded only 8% during storage time, and thus frozen storage well preserves total vitamin C. The low estimated Arrhenius activation energies of texture, starch, and ascorbic acid losses emphasize that low temperatures do not substantially reduce degradation rates.     

Sensory and Instrumental Texture of Snap Bean (Phaseolus vulgaris L.)

A recent study aimed to establish the correlation between instrumental (using Stable Micro System Texture Analyzer) and sensory texture analyses assays in snap bean pods (Phaseolus vulgaris L.). The rupture force correlated significantly and negatively with the sensory traits: parchment layer free, crispness, and stringlessness. Firmness measurements of the raw pods by the texture analyzer indirectly gave enough information to use it as a tool for sensory texture analyses of the processed beans. This could allow breeders to evaluate textural quality of cooked pods in the early stages of the breeding and selection program, thus saving time and costs in doing sensory texture analysis.     

Evaluation of Gelation and Solubility of Bovine Plasma Protein Isolates

Gelation and solubility of bovine plasma protein isolates prepared from liquid plasma using different acids (HCl, H₃PO₄, H₂SO₄) and bases (NaOH, Na₂CO₃) were evaluated and compared to commercial plasma. Protein recovery was over 90%. Solubility at 1% (w/v) was low in pH range 4.0 to 5.5 but similar to commerical plasma in pp range 5.5 to 8.0 (p < 0.01). All isolates gelled at a concentration o 6.0%. Only isolate H₃PO₄-Na₂CO₃ and commercial plasma gelled at a minimum concentration of 4.0%. This concentration decreased to 2.4% for the same isolate when 0.025M Ca⁺⁺ ion was added.     

Physico-chemical and Functional Properties of Common Bean (Phaseolus vulgaris) Starches

Starch was isolated by a simple procedure from two varieties of Phaseolus vulgaris with outstanding agronomic performance. These varieties were negro queretaro and bayocel which have black and light brown colored seeds, respectively. The starch yields were 31.5% for negro qro. and 28.5% for bayocel. Commercial maize starch was used as reference. The granule size followed the order: negro qro. > bayocel > maize. Compared to maize starch, the legume starches had at least a similar water absorption capacity, formed a stable gel at lower concentrations and showed a Hunter total color closer to the employed white standard. The swelling and solubility were both temperature and pH dependent. Effects of pH on the pasting properties were also examined with the Brabender Viscograph. The viscosity of legume starches was increased after holding the paste at 90°C for 15 min. The retrogradation tendency of maize starch was much higher than that of legume samples. The physico-chemical and functional properties of common bean starches might suit some food industrial applications.     

Chemical Composition of White Bean (Phaseolus vulgaris L.) and Functional Characteristics of Its Air-Classified Protein and Starch Fractions

Four varieties of Canadian white bean and their air-classified fractions were analysed for amino acid and proximate composition. The protein enriched fraction (31–35% by wt) prepared by air-classification of finely ground dehulled flour contained 50.3–57.5% protein. Solubility of protein measured as percent of total nitrogen soluble at pH 7.5 was 81.1–83.0%. Water Hydration Capacity and heat thickening property of the protein fraction were similar to other vegetable proteins indicating its potential usefulness as a protein ingredient in processed foods. The amino acid composition was characteristic of leguminous seed proteins with a high lysine content and a low sulfur amino acid content. The lipids and the oligosaccharides were concentrated in the protein enriched fraction. The starch fraction (53% by wt) contained on the average 30% amylose and gave a torque-temperature curve typical of legume starches with slow swelling, no breakdown at constant temperature and shear, and a high set back.     

Protein Solubility, Water Retention, and Fat Binding of Corn Germ Protein Flour Compared with Milk Proteins

Protein solubility (PS), water retention (WR), and fat binding (FB) of corn germ protein flour (CGPF), nonfat dry milk (NFDM), whey protein concentrate (WPC), and sodium caseinate (SC) were comparatively studied using response surface methodology. PS and WR of all samples were affected by pH except for WR of CGPF. PS and WR of all samples were not affected by incubation temperature except of WR of CGPF. Incubation temperature influenced FB of CGPF and WPC but not of NFDM and SC. Sample concentration significantly affected FB of all samples. CGPF was an effective protein source in terms of WR and FB. For FB, SC > CGPF = NFDM > WPC and for PS, WPC=NFDM=SC > CGPF.     

Solubility and Water Absorption of Systems Containing Soy Protein Isolates, Salt and Sugar

Solubility and water absorption of three soy protein isolates in the presence of sodium chloride and sucrose were studied. Water absorption also was investigated in a system that contained wheat flour in addition to the isolates, salt and sugar. Sodium chloride affected nitrogen solubility index and water absorption of the isolates; sucrose did not. Similarly, sodium chloride affected water absorption in the flour-soy system, whereas sucrose did not. An apparent inverse relationship was observed between water absorption of soy protein isolates in the absence of flour and in combination with flour. Dough development times were shorter and doughs were less stable for flour-isolate mixtures than for flour alone.     

Influence of Tannin on Phaseolus vulgaris Protein Digestibility and Quality

The influence of tannin on protein digestibility and quality of black beans was evaluated using an enzyme-Tetrahymena thermophila bioassay. In vitro digestibility and t-PER (Tetrahymena-based PER) were inversely related to tannin content. Bioavailability, expressed by Tetrahymena growth, of black bean globulin G₁ in the presence of black bean condensed tannins correlated well (r=0.95) with the in vitro digestibility of the protein. Black bean condensed tannins complexed readily with black bean globulin G₁ to form insoluble precipitates from pH 2.0 to pH 8.0. Bean tannin-G₁ precipitates, at tannin-to G₁ ratios of 0.55 or greater, were resistant to pepsin digestion at pH 2.0. Digestion of bean tannin-G₁ precipitates was 69–74% at pH 8.0, using a multienzyme system of trypsin, chymotrypsin and peptidase.     

紫花芸豆蛋白体外消化产物的抗氧化活性及结构特征分析

为探究芸豆蛋白在体外模拟胃部消化期间抗氧化活性及结构特征,本实验以紫花芸豆蛋白为原料,采用体外模拟消化模型,并运用多种蛋白分析方法进行检测。结果表明：在消化期间因酶解作用,其水解度及溶解度明显提高,并且随着芸豆蛋白低分子质量肽段数量的增加,消化产物的抗氧化活性显著增加,其中总抗氧化能力、铁离子还原能力分别提高了296.97%、54.01%;通过傅里叶变换红外光谱分析发现,消化过程使芸豆蛋白二级结构发生显著变化,随消化时间的延长,消化产物中α-螺旋相对含量、β-转角相对含量不断提高,β-折叠相对含量不断降低;经模拟消化后的芸豆蛋白暴露巯基、总巯基含量下降幅度均较大,两者随消化时间延长均略有增加;扫描电子显微镜分析发现芸豆蛋白经胃部模拟消化后呈现颗粒状,且无序排列形成细密的网状结构。