Biological study on the effect of supplementing wheat flour with fish protein concentrate.

The protein quality of 4 Egyptian pastries made from different combinations of flour and fish protein concentrate (0%, 4% and 6%) was measured by rat growth study. Weight gain, feed consumption and PER were determined. Weight gain of rats fed cottage cheese crescents was higher than that fed date bars followed by that fed brouche, then rats fed salty sticks. Feed consumed by rats fed with the corresponding commercial pastries was low except in date bars group. Commercial pastries led to low weight gain and low PER values. Supplementing wheat flour with 6% fish protein concentrate gave the highest weight gain and the highest PER values.     

Whey protein concentrate gels with honey and wheat flour

Structural and functional properties of whey protein concentrate (WPC) gels with different honey and wheat flour contents, prepared at pHs 3.75, 4.2 and 7.0, were analysed. Gel structure was observed by scanning electron microscopy. The apparent transition temperatures for protein denaturation and starch gelatinization were determined by differential scanning calorimetry. Gels were characterised through solubility assays in different extraction solutions and polyacrylamide gel electrophoresis of the soluble protein components. The firmness, elasticity, relaxation time, adhesivity and cohesiveness of gels were determined, and the water-holding capacity and superficial colour of gels were also studied. Results suggest that wheat flour could interact with whey proteins, and produces a decrease in the protein solubility of WPC gels, and in the temperature of whey protein denaturation. The effect of wheat flour on the functional properties of WPC gels was different at acidic than at neutral pH: the presence of wheat flour produced an increase in the relaxation time and in the cohesiveness of gels prepared at pH 3.75, whereas at neutral pH a decrease in both properties was observed. Honey and flour content increased the water-holding capacity and browning of WPC gels.     

添加青麦仁粉对小麦粉特性的影响研究

将青麦仁制成全粉添加在小麦粉中,并对它的理化性质、糊化特性及流变学特性进行研究。结果表明:随着青麦仁粉添加量的增大,混合粉的水分、淀粉、湿面筋含量以及面筋指数下降,灰分、蛋白质、膳食纤维、叶绿素、脂肪含量明显升高;粉质特性表现为面团的稳定时间和粉质质量指数下降,吸水率升高,弱化度升高;拉伸特性显示面团的延伸性、能量以及拉伸阻力显著下降;糊化特性呈现出高峰黏度、最终黏度、低谷黏度、回生值以及衰减值整体都呈下降趋势。     

The effect of supplementing goats milk with whey protein concentrate on textural properties of set-type yoghurt

Yoghurt was manufactured from goat's milk and supplemented with 30 g L^?1 of whey protein concentrate (WPC). The textural properties of the yoghurt were evaluated during the shelf‐life of the product and the textural characteristics of yoghurt made from cow's milk were used as a reference. The instrumental analyses used were the puncture test, stress relaxation test and texture profile analysis. The addition of WPC to goat's milk enhanced the textural characteristics of yoghurt. These advantageous attributes included increased firmness, hardness and adhesiveness. These attributes were quantitatively similar (P > 0.05) to those obtained from yoghurt made from cow's milk. In addition, the textural properties were maintained constant throughout the shelf‐life of the product.     

Evaluation of the effect of supplementing fermented milk with quinoa flour on probiotic activity

In this work, we investigated the effect of supplementing fermented milk with quinoa flour as an option to increase probiotic activity during fermented milk production and storage. Fermented milk products were produced with increasing concentrations of quinoa flour (0, 1, 2, or 3 g/100 g) and submitted to the following analyses at 1, 14, and 28 d of refrigerated storage: postacidification, bacterial viability, resistance of probiotics to simulated gastrointestinal (GI) conditions, and adhesion of probiotics to Caco-2 cells in vitro. The kinetics of acidification were measured during the fermentation process. The time to reach maximum acidification rate, time to reach pH 5.0, and time to reach pH 4.6 (end of fermentation) were similar for all treatments. Adding quinoa flour had no effect on fermentation time; however, it did contribute to postacidification of the fermented milk during storage. Quinoa flour did not affect counts of Bifidobacterium animalis ssp. lactis BB-12 or Lactobacillus acidophilus La-5 during storage, it did not protect the probiotic strains during simulated GI transit, and it did not have a positive effect on the adhesion of probiotic bacteria to Caco-2 cells in vitro. Additionally, the adhesion of strains to Caco-2 cells decreased during refrigerated storage of fermented milk. Although the addition of up to 3% quinoa flour had a neutral effect on probiotic activity, its incorporation to fermented milk can be recommended because it is an ingredient with high nutritive value, which may increase the appeal of the product to consumers.     

配粉对小麦粉品质影响作用的研究

研究了不同比例配粉对小麦粉理化品质性状、面团品质性状和焙烤品质性状指标的影响 ,结果表明 :配粉对小麦粉品质的变异有重要作用 ;两种互补性较强的小麦粉以合适的比例相搭配 ,其加工品质的改善程度较为明显 ,但在优质粉所占比例较小时 ,面包体积的改善程度最为显著 ;配粉对混合粉理化品质性状指标的变化规律不太明显 ,影响作用不大     

Effects of wheat flour supplemented with soy protein concentrate on the rheology,microstructure and water mobility of protein-fortified precooked noodles

Wheat flour was supplemented with different levels of soy protein concentrate (SPC) and applied to precooked noodles for protein fortification whose quality attributes were characterised in terms of rheology, microstructure and water mobility. The wheat flours with high levels of SPC showed lower enthalpy values and higher temperatures derived from starch gelatinisation. They also exhibited lower values of the pasting viscosity and dynamic viscoelastic parameters. The mixolab measurements demonstrated that the supplement with SPC was effective in raising the water absorption and dough stability of wheat flour. In addition, the use of SPC-supplemented wheat flours produced precooked noodles with tight and dense structures, which were confirmed by scanning electron microscopic analysis. These microstructural changes were consequently related to higher maximum resistance to extension and lower extensibility of the noodles. However, the SPC-supplemented wheat flours did not significantly affect the cooking loss of the noodles. Furthermore, three water components with different mobility were observed in the precooked noodles whose spin-spin relaxation times were distinctly reduced with increasing levels of SPC. Overall similarities in the sensory noodle attributes were detected as wheat flour was supplemented with SPC at a level of 8% (w/w).     

大豆分离蛋白与小麦粉复配对面制食品品质影响的研究进展

综述了添加大豆分离蛋白对面条、面包、馒头等面制品食用品质的影响,得出在小麦粉中添加适量的大豆分离蛋白后,能够使其蛋白质含量增加,有效地改善面制品的食用品质、面筋强度、流变学性质、营养价值,延长其货架期。     

花生蛋白粉的功能特性及对面粉品质的影响

研究了花生蛋白粉的部分功能特性及添加花生蛋白粉对小麦粉品质的影响。研究表明,花生蛋白粉的吸油性保持在0.8～1.2mL/g,持水性在1.0g/g左右,持水性随pH的上升略有上升。在面粉中添加3%的花生蛋白粉面筋筋力最强,添加量为6%时对缓解面粉的弱化速度效果最好,且温度到90℃时,各种添加量面粉的酶仍然有一点活性。     

配粉技术对小麦粉品质的影响作用

研究了不同比例配粉对小麦粉理化品质性状、面团品质性状和焙烤品质性状指标的影响。结果表明,配粉对小麦粉品质的变异有重要作用;两种互补性较强的小麦粉以合适的比例相搭配,其加工品质的改善程度较为明显,但在优质粉所占比例较小时,面包体积的改善程度最为显著;配粉对混合粉理化品质性状指标的变化规律不太明显,影响作用不大。     

谷朊粉对饺子粉品质改良效果的研究

为了研究谷朊粉对饺子粉品质的改良效果,筛选适宜的添加量,分析了添加不同剂量谷朊粉小麦粉的粉质参数、拉伸参数以及生饺子皮的色泽、质构特性、蒸煮干物质失落率和熟饺子皮的质构特性。结果表明,随着谷朊粉添加量的增加,面团的稳定时间、评价值、拉伸能量、拉伸阻力、最大拉伸阻力、拉伸比例、最大拉伸比例以及穿破生饺子皮所作的功均不断增加,弱化度和生饺子皮亮度逐渐降低。饺子皮的综合评分显示,当谷朊粉添加量为9%时制作的饺子皮品质最好。因此,谷朊粉对饺子粉品质具有明显的改善作用,其最佳添加量为9%。     

Biological value of soy protein concentrate

The chemical score techinique was employed in animal experiments to study the biological value of the protein soybean concentrate. Net utilization of protein, the protein efficacy ratio were determined as were nitrogen balance and its assimilability. The animals' general status and body weight were observed over time. It was discovered that the protein soybean concentrate appeared inferior to casein used as control. The relative biological value of the product under study was found to be high enough, amounting to 82.66% with regard to casein.     

全麦粉及小麦粉基本品质及流变学特性对比研究

以郑麦366、普优、加麦2号3种小麦为原料,分别用波通3100磨磨制全麦粉,布勒实验磨磨制小麦粉。研究全麦粉及小麦粉的基本品质及流变学特性。结果表明:全麦粉的营养价值优于小麦粉的营养价值,但是加工品质劣于小麦粉的加工品质。     

Fluoride content of fish protein concentrate and raw fish

The fluoride content of fish protein concentrate prepared by the Halifax isopropanol process and also of several possible raw materials was determined by distillation without fusion. The concentration of fluoride in this dry material ranged from 20 to 760 ppm and was dependent upon the raw materials. The major source of the fluoride was the bones which were incorporated in the product to a variable extent. The levels in fresh fillets ranged between 2·3 and 5·4 ppm while whole eviscerated fish contained 3·6-57 ppm fluoride.     

粒度对小麦粉及面制品品质影响的研究进展

小麦粉粒度不同,其组成成分和小麦粉品质存在显著差异。随着小麦粉粒度的减小,小麦粉的灰分减小,而色度、干湿面筋含量、损伤淀粉含量、蛋白含量和沉降值逐渐增加。不同粒度小麦粉做出的馒头、面条和面包的差异很大。随粒度的降低,馒头的比容、弹性、回复性增加。粒度越小,馒头的硬度越大,而色泽则越好。面条与面包的感官特性,食用品质等也受小麦粉粒度的影响。因此,在用小麦粉制作面制品时需要综合考虑各种因素。     

Effects of protein hydrolysis on pasting properties of wheat flour

Protein hydrolysis is used widely in the food industry for the purpose of improvement of food or industrial quality, and the processing exists concurrently or subsequently with starch pasting. The effects of protein hydrolysis using papain, pepsin, trypsin, and dithiothreitol (DTT) on flour pasting properties were here investigated at five set concentrations. There were notable decreases in the peak, the trough viscosity, and the integral area of the viscosity curve as the concentrations of papain, trypsin, and DTT increased. DDT and pepsin concentration did not have any effect on final viscosity. Both breakdown and setback showed significant downtrends as the concentration of papain increased but no change as DDT concentration varied. Low concentrations of papain and pepsin prolonged peak time slightly, but higher concentrations shortened it significantly. For trypsin and DTT, low concentrations increased peak time notably, but high concentrations decreased it significantly. Pasting time and temperature increased in the presence of papain, pepsin, and trypsin, more so at higher concentrations. These results supply a basis for the utilization of hydrolyzed protein in the food industry and for the further studies on the interactions between protein and starch during processing.     

The effect of aphid infection and cultivar on the protein content governing baking quality of wheat flour

BACKGROUND: Aphids cause both quantitative and qualitative yield losses in cereals. Aphid feeding resulted in a significant decrease in gliadin/glutenin ratio in soft‐kernel wheat. Effect of aphid feeding on hard‐kernel wheat was examined. RESULTS: Plants of two different hard‐wheat cultivars were artificially infected by two aphid species: Sitobion avenae and Diuraphis noxia. Three different levels of caging regulated aphid density. Aphid density was highest in the cages, followed by open cages and lowest under no‐cage conditions. Numbers of D. noxia were generally higher compared to those of S. avenae. There was no significant difference in head length, mean kernel number/head, mean kernel mass/head or mean individual kernel mass between the two cultivars. Glutenin, gliadin and total protein content was analysed using size‐exclusion HPLC. Quality parameters of wheat flour were significantly different between the two cultivars. Gliadin content, total protein content and gliadin/glutenin ratio were significantly higher in Mv Magdaléna compared to Mv Magvas regardless of the level of caging and infestation, while glutenin content of uninfected Mv Magvas was significantly higher than that of Mv Magdaléna in the open cages. Aphid feeding did not induce any significant reduction in the gliadin, total protein content and gliadin/glutenin ratio of the examined hard wheat cultivars. CONCLUSION: Individual kernel mass reduction is the major factor in yield loss caused by aphids. Aphid feeding did not change the protein structure of hard‐kernel wheat. Copyright © 2007 Society of Chemical Industry     

Effect of extrusion cooking on protein modification in wheat flour

Common soft wheat flour was extruded at three different temperatures and two different moistures. To investigate the dependence of the wheat protein modification on processing conditions, their solubilities in sodium dodecyl sulfate (SDS) were compared with those in SDS+(2-mercaptoethanol) ME. Furthermore, free sulfhydryl groups were detected with Ellmans Reagent and SDS-PAGE was performed under reducing and non-reducing conditions. The solubility values in SDS were greatly reduced after extrusion. The solubility values in SDS+ME were not affected. We therefore concluded that intermolecular cross-linking by disulfide bonding through extrusion cooking had occurred. This result was confirmed by SDS-PAGE under reducing and non-reducing conditions. At low and medium temperatures the solubilities were lower at low moisture; however, more free sulfhydryl groups were detected under these conditions, suggesting that moisture content of the flour has an influence on the way and the nature of the protein polymerization. At the highest thermal energy input at low moisture the solubilities increased again. This was accompanied by an increase of detectable free sulfhydryl groups. This led to the conclusion that disulfide bonds were cleaved at high energy input. The solubility development in 70% ethanol was nearly the same as in SDS. This is seen as a proof that gliadins are highly involved in the protein network formed under extrusion conditions. This finding was also confirmed by the results of SDS-PAGE.     

关于大豆浓缩蛋白强化面粉的探讨

通过对我国人民饮食结构的分析认为蛋白营养强化面粉是我国公众营养的发展方向.根据我国大豆和面粉产业的现状,开发大豆浓缩蛋白强化面粉是充分利用我国大豆资源,提高人们的健康水平,企业获取更大经济效益的有效途径.     

Effect of supplementation with fish protein concentrate on protein and amino acid content of salt biscuit

Fish protein concentrate (FPC) from river Nile bolti fish (Tilapia nilotica) was prepared by two extractions with isopropyl alcohol. This FPC was used as a supplement to manufacture salt biscuit (mixed with cumin) for raising its nutritional quality. The supplementation at level of 4, 5, and 6% increased the protein content by about 2. 6, 3. 5, and 4.5% respectively. Increase was high in some amino acids such as glycine, serine, and threonine while cysteine, lysine, alanine, glutamic acid, arginine, isoleucine, and phenylalanine increased in a low rate. Consumer acceptability was the best at 6% level. The increasing of the supplementation to more than 6%, e. g. 7, and 8% levels caused a drop in the overall quality. There were significant differences in colour and highly significant ones in taste, flavour and texture due to differences in the supplementation level. The presence of all essential amino acids in significant quantities suggests an importance of supplementation of salt biscuit in human nutrition.