不同外源蛋白对小龙虾丸品质的影响

研究小麦面筋蛋白（wheat gluten proteins,WG）、大豆分离蛋白（soybean protein isolate,SPI）和花生分离蛋白（peanut protein isolate,PPI）的添加对小龙虾丸品质的影响。利用质构仪、色差计、低场核磁共振仪等对添加3 种不同外源蛋白小龙虾丸的感官评分、凝胶特性、持水性、蒸煮损失率、白度和横向弛豫时间T2进行测定,并用Pearson法对各指标进行相关性分析。结果表明：不同添加量的3 种非肌肉蛋白均能够改善小龙虾丸凝胶特性,提高保水性,降低蒸煮损失率,改善小龙虾丸内部空间三维网络结构,降低白度,各指标之间相关性显著（P＜0.05）;相比于SPI和PPI,添加WG对小龙虾丸品质的改善最为明显,WG添加量为6%时,小龙虾丸的凝胶强度、保水性比对照组分别增加64.8%和11.3%;小龙虾丸白度随着外源蛋白添加量的增加而降低,其中WG能有效降低对小龙虾丸白度的影响,与SPI和PPI组差异显著（P＜0.05）;PPI添加量2%时,小龙虾丸感官评分和凝胶特性优于WG和SPI组。整体而言,选用添加量6%的WG更能有效提高小龙虾丸品质及消费者可接受度。     

不同蛋白对马铃薯面条食用品质的影响

本研究通过在马铃薯面条原料粉中添加一定比例小麦蛋白、花生蛋白、大豆蛋白制作面条,探讨了三种蛋白对马铃薯面条食用品质的影响。结果表明:三种蛋白均会降低马铃薯面条的亮度值,且随蛋白添加量的增加,马铃薯面条亮度值降低,但大豆蛋白对马铃薯面条亮度值的影响小于小麦蛋白和花生蛋白。同时,三种蛋白均可显著改善马铃薯面条的食用品质,降低其蒸煮损失,增强其拉伸阻力、硬度、粘合性和咀嚼性,且小麦蛋白对面条品质的改善作用最为显著,大豆蛋白次之。扫描电镜结果表明,添加小麦蛋白后马铃薯面条面筋网络形成更加致密,空隙率更小。电子鼻检测结果表明,小麦蛋白和花生蛋白对马铃薯面条的气味无显著影响,而大豆蛋白会使马铃薯面条中的氮氧化合物等豆类腥味物质增加。由此可见,三种蛋白中,小麦蛋白对马铃薯面条的食用品质改善效果最佳。     

脱脂花生蛋白营养面条的制作及品质特性研究

将小麦粉与脱脂花生蛋白粉按100:0、95:5、90:10、85:15、80:20 的比例分别混合,测定混合粉的糊化特性及面筋特性。将混合粉制成速冻面条,通过正交试验及感官评定确定脱脂花生粉与小麦粉的比10:90,加水量40%,加盐量2.5% 制脱脂花生蛋白营养面条。对脱脂花生粉速冻面条的品质特性进行评价显示：随着脱脂花生粉添加量的增加,混合粉的面筋含量及糊化性质降低,面条的质构特性下降,蒸煮损失率增加;分析0～28d 冷冻贮藏后品质特性：随着贮藏时间的增加,面条的硬度、拉伸强度、拉伸距离在贮藏前期呈下降趋势,16d 后趋势平缓。弹性、内聚性、回复性略有上升,但不显著,显示花生蛋白营养面条具有较好的耐贮藏性;按中国营养膳食营养要求及每人每日食用200g 面条计算,配方提供的蛋白质含量占儿童、老年人所需的60%、44%。添加脱脂花生粉使得面条质地松软,有着良好的食用品质和营养价值,宜被老年人和儿童接受。     

花生蛋白营养面条的品质评价

将花生蛋白粉添加到小麦粉中制得花生蛋白营养面条,利用感官评价、质构仪对花生蛋白营养面条、普通面条、乌冬面条的品质进行分析.结果表明:TPA分析得花生蛋白营养面条的最大剪切力和拉断力分别比普通面条高出16.36 g和35.26 g,比乌冬面条高出5.17 g和3.997 g.花生蛋白营养面条色泽微黄,具有花生的香味.花生蛋白粉的添加量在6%时面条的感官性状适中,质构特性较好,与普通面条相比,每100 g花生蛋白营养面条的蛋白质含量提高2.4 g.按照中国膳食营养推荐摄入量,儿童、老年人每日所需蛋白质摄入量分别为55、75 g,每人每日食用200 g面条计算,配方提供的蛋白质含量占儿童、老年人所需的54%、40%.     

添加发芽小麦对小麦粉及制品品质影响

在小麦中添加不同比例的发芽小麦,研究对小麦、小麦粉品质特性及食用品质的影响。选择发芽小麦按照不同比例(1%、5%、10%、15%、20%、25%、30%)与正常小麦进行混合,研究发芽小麦不同添加比例对小麦及小麦粉品质特性产生的影响,并对不同添加比例发芽小麦粉制作的馒头和面条食用品质进行评价。结果表明:随着发芽小麦比例含量的增加,混合小麦及小麦粉品质特性指标中除降落数值逐渐减少,其他特性指标与正常小麦相比较无明显变化。对馒头和面条进行蒸煮实验评价,可以看出当发芽小麦含量不超过15%时,对其食用品质无明显影响,但当发芽小麦含量超过20%时,馒头出现粘牙,当发芽小麦含量超过15%时,面条韧性下降,食用品质受到影响,评分值均在80分以下。     

花生蛋白对面条品质的影响

通过在面粉中添加不同比例的花生蛋白,分析其对面粉湿面筋含量、面团流变学特性、面条蒸煮品质、感官品质和质构品质的影响。结果表明:在面粉中加入4%的花生蛋白,可显著提高面粉的蛋白质和湿面筋的含量,改善面团的流变学特性;制作的面条韧性和口感较好,增加了面条的营养价值,并且对面条加工特性没有太大影响。     

大豆分离蛋白对面条品质的影响研究

通过在面粉中添加不同比例的大豆分离蛋白，分析其对面粉蛋白质品质、面团流变学特性、面条色泽及蒸煮品质、感官品质的影响。结果表明：在面粉中加入7％-9％的大豆分离蛋白质，可显著提高面粉的蛋白质含量，湿面筋的含量，改善面团的流变学特性，制作的面条韧性和口感较好；无明显豆腥味，既增加了挂面的营养价值，又提高了挂面的加工工艺特性。     

小麦面筋蛋白对冷冻莜面水分分布和食用品质的影响

为了研究小麦面筋蛋白对冷冻莜面水分分布和食用品质的影响,将小麦面筋蛋白以不同比例添加到莜麦粉中制成冷冻莜面。研究小麦面筋蛋白对莜麦粉的糊化特性的影响,进而探究对冷冻莜面蒸煮品质、质构特性、水分状态与分布以及微观结构的影响。结果表明:添加质量分数10%小麦面筋蛋白能够显著(P0.05)降低冷冻莜面的蒸煮损失和断条率,明显降低莜面粘连度,可冻结水含量下降,冷冻莜面的微观结构更加致密,感官品质变好。     

纤维素酶处理改善糙米米线食用品质的研究

为降低膳食纤维对糙米米线的蒸煮、食用品质的不利影响，该研究尝试通过纤维素酶处理糙米粉改善糙米米线的食用品质，探讨了纤维素酶的最佳处理时间和添加量，并通过糙米粉糊化特性、凝胶特性和糙米米线基于低场核磁的水分分布等初步分析其作用机制。结果显示，纤维素酶最适处理时间为2 h、最适添加量为0.2%，此时，与对照比较，最佳蒸煮时间由8.7 min增加到10.6 min，断条率由22.2%降到4.4%，蒸煮损失率由32.1%降到16.6%，糙米米线质构中的硬度、咀嚼性、拉伸强度显著提高，黏性显著下降，糙米米线的蒸煮、食用品质得到改善；适当纤维素酶处理，使糙米米粉糊化特性的峰值黏度、谷值黏度、衰减值、最终黏度和回生值下降，凝胶特性的硬度增加；同时，基于低场核磁的水分分布表明，处理后的糙米米线中结合水的比例增加，自由水的比例下降。研究表明纤维素酶处理可以影响到糙米米线中淀粉的糊化和老化，从而改善其蒸煮和食用品质。     

谷氨酰胺转氨酶对大豆与小麦混合蛋白凝胶性质的影响

研究谷氨酰胺转氨酶（transglutaminase,TG）对大豆和小麦混合蛋白凝胶特性的影响,通过游离巯基含量、表面疏水性、热特性、二级结构和微观结构等测定对混合蛋白凝胶的构象进行了表征。结果显示,当大豆蛋白比例低于45%时,随着大豆蛋白所占比例的增加,凝胶强度显著增强。TG交联混合蛋白凝胶后,其游离巯基减少,热稳定性增强,表面疏水性降低。与TG催化小麦蛋白相比,大豆蛋白添加量为45%的混合蛋白凝胶强度提高了62.74%,β-折叠含量增加了5.701%,游离巯基含量减少了47.48%。     

Short communication: Muscle protein synthetic response to microparticulated whey protein in middle-aged men

Whey protein concentrate (WPC) is a high-quality dairy ingredient that is often included in formulated food products designed to stimulate muscle anabolism. Whey protein concentrate can be affected by UHT processing, and its sensory properties are not compatible with some formulated food products. Microparticulated WPC (mWPC) is a novel ingredient that is resistant to heat treatment and has enhanced sensory properties. When 16 healthy middle-aged men consumed 20 g of either WPC or mWPC, both proteins increased plasma essential AA and leucine concentrations with no detectable difference in curve kinetics. Myofibrillar protein synthesis was increased in both groups for 90 min after ingestion with no difference between groups. Ingestion of mWPC resulted in a muscle anabolic response that was equivalent to that of WPC over the full 210-min measurement period. Formulated products incorporating mWPC or standard WPC would provoke equivalent anabolic responses.     

大豆分离蛋白与谷朊粉可食性复合膜研究

该文报道影响大豆分离蛋白与谷朊粉复合膜成膜因素,分析各种因素对复合膜性能影响,并对正交试验结果采用极差分析和综合评分法进行评定,得到制备综合性能良好的可食性膜最佳条件为:谷朊粉与大豆分离蛋白比例为1∶5,甘油量为20%,pH为11,预热处理温度和时间分别为80℃和40min;此时,膜的透光率、拉伸强度、撕裂强度、水分含量和水蒸汽透过率依次为60.5%、38.38MPa、198.02N/mm、13.87%和0.507g·mm/kPa·h·m2。     

芝麻蛋白研究概况

简述芝麻蛋白的结构及氨基酸组成、蛋白质性质和应用,并展望进一步研究芝麻蛋白的 前景。     

Protein–protein interactions of a whey–pea protein co-precipitate

The aim of this study was to investigate the mechanisms behind protein–protein interactions in a co-precipitate of whey protein isolate (WPI) and pea protein isolate (PPI). A co-precipitate and blend, consisting of 80% WPI and 20% PPI, were compared. Covalent disulphide interactions were studied by blocking of free thiols with N-Ethylmaleimide (NEM), while electrostatic interactions were studied in systems with 0.5 m NaCl and hydrophobic interactions with 0.2% SDS. Protein solubility, stability and secondary, tertiary and quaternary protein structures were analysed. Co-precipitation did not introduce different protein–protein interactions than the direct blending of proteins. SDS affected solubility (P < 0.05), secondary and tertiary structure. However, the effects of NEM and NaCl were significant greater (P < 0.05) on the same parameters and thermal stability, especially when combined (P < 0.01). Thus, the protein–protein interactions in a whey–pea co-precipitate and protein blend consisted of disulphide bonds and electrostatic interactions.     

Production of safflower protein isolates: Composition,yield and protein quality

The use of laboratory- and commercially-prepared safflower meal for the production of protein isolates is described. The isolates were obtained by micellisation and isoelectric precipitation techniques, the latter being the most efficient procedure. Previous treatments received by the meal, for example heating, influenced the protein recovery. In general, isolates produced by micellisation were more soluble than samples obtained by isoelectric precipitation. The colour of the protein isolates depended on the isolation technique and type of safflower meal utilised. All isolates had a similar amino acid composition and levels of in-vitro protein digestibility.     

大豆分离蛋白中蛋白质含量的快速测定

采用基于经典凯氏定氮法原理设计的KDN-08A半自动定氮仪对大豆分离蛋白中蛋白质含量进行快速测定.结果经t检验,与经典凯氏定氮法测得结果无显著性差异,且回收率在99.53%～100.19%之间.表明该方法测定结果准确可靠、操作简单快速,适用于大豆分离蛋白中蛋白质含量的测定.     

氯化钠浓度对亲脂性蛋白和7S蛋白分级分离效果的影响

研究了氯化钠浓度对大豆蛋白中亲脂性蛋白(LP)与7S蛋白分级分离效果的影响,并采用差示扫描量热法(DSC)探讨了氯化钠浓度对蛋白质热变性的影响。研究表明:当氯化钠浓度低于100 mmol/L时,7S级分蛋白质得率会显著增加且蛋白质含量基本不变,所得7S级分纯度也有所提高(特别是50 mmol/L时);氯化钠浓度在0~100 mmol/L范围内LP蛋白质得率几乎不受影响,但蛋白质含量有所降低。各级分的热变性分析表明:7S组分的热变性温度不受氯化钠浓度的影响,但吸热峰焓值变化较大。当氯化钠浓度为50 mmol/L时对LP和7S的分级分离效果最好。     

Solubility of commercial milk protein concentrates and milk protein isolates

High-protein milk protein concentrate (MPC) and milk protein isolate (MPI) powders may have lower solubility than low-protein MPC powders, but information is limited on MPC solubility. Our objectives in this study were to (1) characterize the solubility of commercially available powder types with differing protein contents such as MPC40, MPC80, and MPI obtained from various manufacturers (sources), and (2) determine if such differences could be associated with differences in mineral, protein composition, and conformational changes of the powders. To examine possible predictors of solubility as measured by percent suspension stability (%SS), mineral analysis, Fourier transform infrared (FTIR) spectroscopy, and quantitative protein analysis by HPLC was performed. After accounting for overall differences between powder types, %SS was found to be strongly associated with the calcium, magnesium, phosphorus, and sodium content of the powders. The FTIR score plots were in agreement with %SS results. A principal component analysis of FTIR spectra clustered the highly soluble MPC40 separately from the rest of samples. Furthermore, 2 highly soluble MPI samples were clustered separately from the rest of the MPC80 and MPI samples. We found that the 900 to 1,200 cm⁻¹ region exhibited the highest discriminating power, with dominant bands at 1,173 and 968 cm⁻¹, associated with phosphate vibrations. The 2 highly soluble MPI powders were observed to have lower κ-casein and α-_S1-casein contents and slightly higher whey protein contents than the other powders. The differences in the solubility of MPC and MPI were associated with a difference in mineral composition, which may be attributed to differences in processing conditions. Additional studies on the role of minerals composition on MPC80 solubility are warranted. Such a study would provide a greater understanding of factors associated with differences in solubility and can provide insight on methods to improve solubility of high-protein milk protein concentrates.     

大米蛋白研究进展

大米蛋白是一种营养价值很高植物蛋白质,其必须氨基酸构成完整,过敏性低;近年研究发现,其还具有重要保健功能,如抗糖尿病、抗胆固醇、抗癌变等。该文介绍大米蛋白结构组成、营养特性、提取方法及应用研究进展。