大豆分离蛋白对湿米粉储藏品质的影响

以湿米粉储藏过程中硬度、蒸煮损失和断条率的变化为指标,研究大豆分离蛋白对湿米粉品质的影响。结果表明,大豆分离蛋白会导致湿米粉硬度的升高,但在储藏过程中添加大豆分离蛋白的湿米粉硬度低于未添加大豆分离蛋白的湿米粉,这表明大豆分离蛋白可显著改善湿米粉在储藏过程中的硬度升高现象;当大豆分离蛋白添加量低于4%时,湿米粉的蒸煮损失和断条率均随大豆分离蛋白添加量的增加而下降;但大豆分离蛋白添加量达6%时,湿米粉的蒸煮损失和断条率上升。结果表明适量的大豆分离蛋白可改善湿米粉的食用品质,但大豆分离蛋白添加量不是越多越好。差示热量扫描和微观结构分析发现大豆分离蛋白可抑制湿米粉中淀粉的回生,赋予米粉蜂窝状多孔结构,有利于米粉在储藏过程中保持水分不发生迁移从而提高湿米粉品质。     

Effect of adding zein,soy protein isolate and whey protein isolate on the physicochemical and in vitro digestion of proso millet starch

Mixtures of proso millet starch with zein (15%, w/v), soy protein isolate (SPI, 15%, w/v) and whey protein isolate (WPI, 10%, w/v) as starch–protein composites were prepared through heat–moisture treatment, and the effects of protein addition on the physicochemical, structural and digestibility properties of starch were investigated. Rapid Visco Analysis showed that the addition of zein, SPI and WPI gave significantly decreased setback values to 240.7cp, 192.0cp and 83.0cp, respectively, and setback values decreased reflected the excellent cold paste properties. Thermal analysis showed that each protein reduced the enthalpy, but especially WPI (reduced by 94.7%), suggesting that the double helices of the starch granules were decreased. X-ray diffraction showed that starch crystallinity was decreased after protein addition. The digestibility studies revealed that the addition of zein, SPI and WPI decreased the content of rapidly digestible starch and increased the resistant starch content to 8.4%, 14.6% and 17.5%, respectively. The whey protein displayed a more obvious impact on the digestibility of proso millet starch. These results will help guide the production and processing of starchy foods with desirable properties.     

Influence of extrusion variables on the protein in vitro digestibility and protein solubility of extruded soy tarhana

Tarhana, supplemented with 150 g kg⁻¹ full‐fat soy flour, was extruded at different extrusion conditions (barrel temperature: 80–120°C; screw speed: 100–300 rpm; feed rate: 10–20 kg h⁻¹ ) using a twin‐screw extruder. The effect of extrusion conditions on the in vitro digestibility (PD) of the protein and protein solubility (PS) was investigated using response surface methodology. Regression equations for predicting PD and PS were developed. While the barrel temperature had a significant effect on PD (P <0.1), feed rate was the most significant variable on PS of the samples (P<0.05). Since the protein solubility should be high for the instant properties of extruded soy tarhana soup, it is suggested that soy tarhana should be extruded at low feed rates (ie high residence times) while high barrel temperatures should be achieved for the inactivation of antinutritional factors present in the soy flour. © 1999 Society of Chemical Industry     

Supplementation of pearl millet flour with soybean protein: effect of cooking on in vitro protein digestibility and essential amino acids composition

In vitro protein digestibility (IVPD) and amino acids profile of pearl millet (Dempy cultivar) supplemented with soybean protein (5–15%) were investigated. Supplementation of dempy flour with soybean protein steadily decreased IVPD with increasing the portion of soybean in the blend. The in vitro protein digestibilities of the cooked supplemented dempy flours were higher when compared with the raw ones, whereas the highest value was that of the 5% soybean protein. All essential amino acids of dempy flour were enriched on supplementation with soybean protein. The levels of amino acids increased with increasing the amount of soybean protein in the blend. Essential amino acids in dempy supplemented with 15% soybean are comparable to those in the FAO reference pattern. Supplementation increased significantly lysine to 1.5–2.4 folds. Essential amino acids content remained higher in the cooked composite flours when compared with the cooked native dempy flour.     

大豆蛋白肽对面条质构和蒸煮品质的影响

在可控条件下制备了水解度(DH)为4％、7％和9％的大豆蛋白肽(SPP),以面粉质量3％替代面粉制备强化面条,考察SPP对面条品质的影响.结果 表明:在相同DH条件下制备的SPP强化面条其品质差异不大,其弹性、回复性和内聚性组间差异不明显,硬度、咀嚼性和拉断力略有差异,但其差异性小于不同DH条件下制备的强化面条.     

双螺杆挤压对花生蛋白体外消化率影响研究

采用双螺杆挤压技术,研究喂料速度、物料含水量、螺杆转速、挤压温度对花生蛋白体外消化率影响。在单因素试验基础上,通过二次通用旋转试验确定花生蛋白体外消化率最佳挤压工艺条件:喂料速度0.3kg/min、物料含水量37.5%、螺杆转速130r/min、挤压温度145℃,在该工艺条件下,花生蛋白体外消化率可达93.91%。     

Effects of red lentil protein addition on textural quality and starch digestibility of brown rice noodles

In this study, the additions of red lentil, rice protein and lentil protein on the quality of brown rice (BR) noodles were investigated, aiming to develop nutritionally fortified noodles with both desirable textural quality and lower starch digestibility. The results showed that the additives reduced the hardness, cohesiveness and chewiness, and increased cooking loss and turbidity of rice noodles. The addition of lentil protein had less effect on the texture quality of rice noodles when compared with the red lentil and rice protein. Lentil protein decreased the starch digestibility of BR noodles, thereby reducing the estimated glycemic index (eGI) from 70.48 to 65.33. XRD and FTIR revealed that lentil protein increased the relative crystallinity and 1047/1022 cm⁻¹ ratio. Ordered structure could effectively limit the interaction between amylase and starch, and reduce its digestibility. Therefore, lentil protein was more suitable to be added in BR noodles to reduce starch digestibility.     

热塑挤压蒸煮处理技术对大豆蛋白基本特性的影响

利用双轴挤压蒸煮处理技术对大豆蛋白进行处理,从质构特性、功能特性及营养特性等三方面对挤出物的组织化效果进行研究。以三个挤压操作参数供水率、螺杆转速和腔体温度为输入参数,挤出物的最大剪切力、复水率、持水率和蛋白质体外消化率为响应参数,探索挤压蒸煮系统操作参数对大豆蛋白质基本特性的影响规律,统计分析表明,三个挤压操作参数与响应参数之间存在显著的相关关系,所得拟合回归模型具有较高的可信度。挤压蒸煮处理操作参数对大豆蛋白的组织化效果有明显影响。     

鲢鱼酶解物对冻融鱼糜制品品质及其蛋白质体外消化率的影响

选择复合蛋白酶水解鲢鱼制酶解产物,以添加了商业抗冻剂(商抗,4%蔗糖+4%山梨醇)的鱼糜制品作对照,综合评价添加了鲢鱼酶解产物的鱼糜制品冻融前后品质及其蛋白质体外消化率的变化。试验结果表明:冻融后,鱼糜制品中添加2%的酶解产物可以增加鱼糜凝胶持水性,降低蒸煮损失,并且不会导致鱼糜制品带上酶解产物本身的淡黄色;同时,2%酶解产物添加组能有效减缓鱼糜制品凝胶强度、硬度和弹性的降低及其蛋白质消化率的下降程度;2%酶解产物添加组在冻融前后感官评分均较高,酶解产物的添加避免了商业抗冻剂给产品带来的明显甜味。研究表明,鲢鱼酶解产物可作为潜在的抗冻剂应用于鱼糜及其制品的工业化生产。     

Sourdough on quinoa and buckwheat gluten-free breads: Evaluation of autochthonous starter fermentation on bread nutritional and technological properties

The aim of this work was to evaluate the effect of two autochthonous strains of lactic acid bacteria as sourdough (SD) starters on gluten-free bread technological quality and in vitro starch hydrolysis and antioxidant activity. Two strains of Limosilactobacillus fermentum isolated from buckwheat (BW) and quinoa flours were used. SDs were prepared from wholegrain quinoa or BW flours. Bread technological properties, total polyphenol content and in vitro antioxidant activity and starch hydrolysis and dialysability were assessed. Specific bread volumes were between 2.61 and 2.76 cm³ g⁻¹. Breads with quinoa-based SD had overall higher technological quality than breads made with BW SDs, shown by a softer, well-aerated crumb, with an opener crumb structure and larger air area. Crumb firming during storage was reduced up to 29% when quinoa SD was used, and up to 42% when BW SD was added. Quinoa breads showed higher polyphenols and FRAP values, whereas BW breads had significantly higher ABTS values. Total starch hydrolysis and dialysability were significantly reduced when SD was used. Starch hydrolysis was reduced up to 42% and 25% when quinoa and BW SD were used, respectively. SD application produced breads with higher technological quality and modified in vitro starch hydrolysis and antioxidant capacity. Even though these effects seemed to be influenced by pH, a biological effect was also observed.     

Effect of extrusion on in situ ruminal protein degradability and in vitro digestibility of undegraded protein from different feedstuffs

BACKGROUND: The effect of extruding maize, barley, whole soybean (WSB), peas, lupins and soybean meal (SBM) on their in situ ruminal protein degradability and in vitro digestibility of the rumen undegraded protein (RUP) was studied. Two mixtures containing 0.75 WSB or lupins and 0.25 maize were also formulated. RESULTS: Extrusion of maize resulted in an increase of its effective protein degradability from 0.538 to 0.734 (P < 0.001), whereas the opposite occurred with barley (from 0.854 to 0.797; P < 0.001). Extrusion increased the in vitro digestibility of the RUP of both cereals, increasing therefore the amount of barley crude protein (CP) digested in the intestines (PDI) from 62 to 176 g kg^?1 CP (P < 0.01), whereas maize resulted in lower (332 versus 229 g kg^?1 CP; P < 0.01). Extrusion decreased (P < 0.001) the protein degradability of the three legume seeds and increased (P < 0.001) the in vitro digestibility of the RUP, resulting in a PDI increase (P < 0.001), from 60 to 367 g kg^?1 CP for peas, from 69 to 265 g kg^?1 CP for WSB and from 107 to 205 g kg^?1 CP for lupins. This effect was enhanced when WSB was extruded jointly with maize. The extrusion of SBM also resulted in an increase in the PDI from 296 to 384 g kg^?1 CP (P < 0.001). CONCLUSION: Extrusion decreases the rumen protein degradability of legume seeds, soybean meal and barley, and increases the digestibility of the RUP, resulting in an increase in the feed protein digested in intestine. The extrusion of soybean seeds together with maize enhances these effects. Copyright © 2008 Society of Chemical Industry     

Effect of fermentation and cooking on protein quality of maize (Zea mays L.) cultivars

Maize like other cereals shows qualitative and quantitative deficiency in protein content. Efforts were made to correct this by fortification, supplementation and fermentation. Two maize cultivars, Hudeiba 1 and Mugtama 45, were used to study the effect of fermentation followed by cooking on their protein quality. Maize flour was fermented for 32 h; samples were withdrawn at 8 h intervals. Results indicated that the proteins fractions albumins plus globulins were significantly (P < 0.05) increased in the fermented doughs. This is an indication of improvement in the protein quality of maize. Cooking resulted in significant (P < 0.05) changes in protein solubility. The essential amino acids particularly lysine increased from 1.82 to 2.06 and from 1.88 to 2.60 g/100 g (i.e. an increase of 11.6% and 27.7%) for Hudeiba 1 and Mugtama 45, respectively. The in vitro protein digestibility of cooked samples decreased significantly (P < 0.05); however, the negative effects of cooking were lower than those of unfermented cooked samples.     

大豆分离蛋白、木薯淀粉与转谷氨酰胺酶组合对鲢鱼鱼糜凝胶品质的影响

探究了大豆分离蛋白、木薯淀粉及转谷氨酰胺酶对鲢鱼鱼糜制品的影响并确定最适添加量。结果表明,当大豆分离蛋白添加量6%,木薯淀粉添加量9%以及转谷氨酰胺酶添加量4U/g·蛋白时,能有效增加鱼糜的持水性,降低其蒸煮损失,且不会使鱼糜带有大豆分离蛋白的淡黄色,同时提高了鱼糜的凝胶强度,鲢鱼鱼糜制品各项指标较好。通过低场核磁共振和扫描电镜检测发现,未添加的对照组在6次冻融后凝胶结构完全被破坏,不易移动水峰面积(A_(23))下降了25%,试验组凝胶结构比较致密,A_(23)下降了11%,进一步验证了此配方组合对鱼糜在冻融循环过程中凝胶结构的稳定性具有保护作用。     

体外模拟法测定婴儿奶粉中蛋白质的消化率

采用体外模拟的方法测定了婴儿奶粉中蛋白质的消化率。此法的重现性试验的相对标准偏差为1．73％，表明重现性较好。测定结果表明：各种不同原料间蛋白质的消化率差异显差。此法快速，简便，重现性好，可应用于婴儿食品质量的评定。     

Concentration of soy protein isolate affects starch-based confections' texture, sensory, and storage properties

The effects of increasing soy protein isolate concentration on the physico-chemical properties of starch-based grape confectionery gels were investigated using thermal, textural, and sensory analyses. Soy protein isolate decreased hardness, cohesiveness, and gumminess, demonstrating potential as a texture modifier. Increasing soy protein concentration progressively decreased the elastic properties of the starch network demonstrated by a lower G'-G" crossover frequency. High levels of soy protein also created a more homogeneous water population, one which was lost at lower temperatures compared to standard confections. An improvement in taste and texture acceptability of the confections upon addition of soy protein isolate was found by sensory analysis. Finally, physico-chemical properties were compared up to 20 d of storage at ambient temperature. Soy-containing confections demonstrated lower gumminess and cohesiveness during the entire storage period but a significant increase in hardness after 20 d of storage. PRACTICAL APPLICATION: Soy protein isolate imparted soft texture to starch-based confections on a concentration-dependent basis. Increasing soy protein isolate concentration decreased elastic properties of the starch network in starch confections and significantly improved flavor and texture. Gumminess and cohesiveness of soy protein isolate confection was lower during 20 d of storage.     

环氧氯丙烷交联淀粉的制备及其体外消化性能的研究

以环氧氯丙烷为交联剂,制备土豆交联淀粉。用正交实验考察环氧氯丙烷用量、氢氧化钠用量、反应温度和反应时间四个因素对交联度的影响,确定最佳工艺条件,并对体外消化条件进行优化,对不同交联度淀粉的消化速度进行研究。体外淀粉消化条件的优化实验显示,消化产物测定的最佳条件为：波长485nm,显色温度100℃,显色时间30min,葡萄糖浓度范围0～80μg/mL,其回归方程为y=0.0044x-0.005,R2=0.9988,且样品溶液在2h内显色稳定。各因素对交联淀粉制备影响的重要性依次为环氧氯丙烷用量、氢氧化钠用量、温度及反应时间;最佳工艺条件为：以50g土豆淀粉计,环氧氯丙烷用量为1.00mL,氢氧化钠用量为0.75g,温度50℃,时间6h,土豆交联淀粉和交联前相比,消化性降低了13.7%～34.5%,且与交联度呈负相关。     

小麦粉中蛋白质和淀粉含量对面条品质的影响

对小麦粉中的蛋白质和淀粉组分进行了分离,将淀粉含量不同的混合粉制作成面条,分析其质构特性和食用品质。将面条煮制后,对熟面条进行了质构分析,测定了熟面条的硬拉伸性能、剪切性能和蒸煮损失,并进行了感官品质评价。研究结果表明:随着小麦粉中的淀粉含量的增加(蛋白质含量的降低),面条的质构特性、拉伸性能、剪切性能都呈现显著下降的变化趋势(P<0.05),而面条的蒸煮损失显著增加(P<0.05)。此外,面条的感官评价与质构分析的结果相一致。     

高水分组织化复合蛋白的挤压制备及品质特性研究

以大豆分离蛋白、谷朊粉和豌豆蛋白为原料,采用高水分挤压技术制备组织化蛋白产品,研究了挤压参数对产品品质特性的影响,分别优化出以大豆分离蛋白和豌豆蛋白为主料的两种产品的配方及挤压参数。结果表明,水分添加量对产品品质特性影响显著;螺杆转速在280r/min,挤压温度在160℃时制备的产品具有较好的质构特性和拉丝效果;当大豆分离蛋白添加量40%,谷朊粉添加量35%,豌豆蛋白添加量25%,水分添加量14.0kg/h时,制得的组织化蛋白产品表面光滑,成型性好,可作为鸡肉仿肉制品;当豌豆蛋白添加量45%,谷朊粉添加量35%,大豆分离蛋白添加量20%,水分添加量13.5kg/h时,制得的组织化蛋白产品拉丝状态明显,质构特性指标与牛肉相似。