菊粉对绿豆蛋白低脂植物酸奶品质的影响

本研究考察菊粉作为脂肪替代物对绿豆蛋白低脂植物酸奶品质的影响。以添加3%葵花籽油的绿豆蛋白酸奶作为高脂酸奶对照,通过分析不同浓度的菊粉（2%、4%、6%）对绿豆蛋白低脂酸奶（1%葵花籽油）的粘弹性、质构、持水力、微观结构及感官品质的影响,评价菊粉的代脂效果。结果表明,与对照绿豆蛋白高脂酸奶相比,添加2%菊粉的绿豆蛋白低脂植物酸奶的粘弹性、硬度、咀嚼性、持水力和感官品质与绿豆蛋白高脂酸奶相当（P>0.05）,表现出均匀致密的蛋白质网络结构。添加4%菊粉的绿豆蛋白低脂酸奶的硬度和咀嚼性分别显著提高了21.56%和32.34%（P<0.05）,持水能力达到88.55%。此时,绿豆蛋白低脂酸奶也表现出致密的网络结构,整体的感官品质最佳。添加6%菊粉的绿豆蛋白低脂酸奶的粘弹性、硬度、咀嚼性和持水力显著高于绿豆蛋白高脂酸奶（P<0.05）,但是其微观结构表现出多孔以及不均匀的蛋白质网络结构,质地和口感变差,总体感官品质最差。因此,添加2%~4%的菊粉能够显著提升绿豆蛋白低脂酸奶的品质,具有较好的脂肪替代效果。本研究结果为研发高品质的绿豆蛋白低脂酸奶提供理论依据。     

EGCG修饰对乳清蛋白乳液冷凝胶特性的影响

研究不同浓度表没食子儿茶素没食子酸酯(EGCG;2.7,13.3,26.6μmol多酚/g蛋白质)对乳清蛋白乳液冷凝胶微观结构及凝胶特性的影响.采用动态光散射和凯氏定氮法测定乳液的粒径、带电性质和界面蛋白吸附量,激光共聚焦显微镜观察乳液微观结构,分析EGCG对蛋白乳液微观结构和特性的影响.采用质构仪单轴压缩法测定凝胶强...     

改性乳清蛋白对低脂Mozzarella干酪品质的影响

将自制脂肪替代品-改性乳清蛋白加入到经标准化的牛奶中,采用无盐渍新工艺方法代替传统方法制作低脂Mozzarella干酪,通过干酪品质测定,确定改性乳清蛋白的最适添加量以及对低脂Mozzarella干酪品质的影响.结果表明:脂肪替代品的最适添加量为1.5%.与全脂组相比.虽然低脂组在风味上存在-定差距.但可满足人们追求健康的现实需要,并且脂肪替代品的加入可增加干酪的亮度值.降低黄度值,对褐变性影响不大,但结构比较致密.     

卵磷脂对乳清分离蛋白乳液性质和乳液凝胶结构特性及其所负载β-胡萝卜素的影响

目的 研究卵磷脂(lecithin,LEC)添加对乳清分离蛋白(whey protein isolate,WPI)乳液的理化性质和乳液凝胶体系的微观结构、流变特性及其所负载β-胡萝卜素热稳定性的影响。方法 以未添加LEC乳液为对照,测定添加不同浓度LEC (0.1%～0.5%)所制备WPI乳液的粒径、ζ-电位及乳液稳定性,并将上述乳液经酸诱导处理后制成乳液凝胶,分析其微观结构形态、流变特性及所负载β-胡萝卜素热稳定性的变化。结果 LEC可通过降低蛋白质溶液的界面张力而使得其乳液的粒径、多分散系数(polydispersity, PDI)值降低,从而有效改善乳液的稳定性;同时LEC的加入显著提高了WPI-LEC乳液凝胶的表观黏度和黏弹性模量,表明有助于形成结构更加紧密的乳液凝胶体系,使得β-胡萝卜素在100℃加热10 h后保留率可达60%。结论 通过添加LEC来提高WPI乳液的稳定性,可以有效改善其乳液凝胶的流变特性和微观结构,从而增强所负载β-胡萝卜素的稳定性。     

酪蛋白与乳清蛋白比例对酸奶凝胶性质的影响

研究了乳中酪蛋白和乳清蛋白比例对凝固型酸奶流变学特性和微观结构的影响,结果表明,固定蛋白质质量分数、降低酪蛋白和乳清蛋白的比例,可以明显提高酸奶凝胶的质量.乳中蛋白质质量分数一致时,酸奶凝胶的硬度、黏度、持水力随着酪蛋白和乳清蛋白比例的减小而增大,凝胶网络结构变得更规则、致密,孔隙更小.在低蛋白质质量分数下,降低乳中酪...     

热处理温度及蛋白浓度对乳清分离蛋白-黄油乳液体系的影响

稳定的乳清分离蛋白（WPI）-黄油乳液体系在乳制品加工及乳制品营养传递系统中有良好的应用前景。对不同质量分数（2%、4%、6%、8%）的WPI分别进行不同的热处理（未加热、80 ℃和90 ℃）,加入黄油并进行超声波处理,制备成乳液,对乳液体系粒径、絮凝指数（FI）、乳化活性（EA）、乳化稳定性（ES）、物理稳定性、储藏期粒径变化和脂肪上浮情况进行分析。结果表明：随着热处理温度的升高,乳液的平均粒径增大,未加热乳液平均粒径均小于1 μm,经加热处理后,不同蛋白质量分数乳液的粒径均有不同程度的增大;经过热处理,乳液的EA和ES均有所改善;随着蛋白质量分数的增大,乳液的物理稳定性提高,其中WPI质量分数为6%和8%时,90 ℃热处理样品的稳定性指数（TSI）均小于0.6,稳定性最好,同一蛋白质量分数下,热处理温度越高,蛋白对乳液的稳定作用越强;乳液储藏期脂肪上浮情况与热处理温度和蛋白质量分数显著相关,较高的蛋白质量分数及热处理温度能够改善乳液体系中脂肪上浮情况。研究表明,通过控制蛋白质量分数和WPI热处理温度可以有效提高WPI-黄油乳液体系的乳化特性及稳定性。     

乳清浓缩蛋白对搅拌型酸奶品质特性影响的研究

研究了以全脂奶粉和乳清浓缩蛋白（WPC-3503）为原料，按照全脂奶粉：乳清浓缩蛋白为100：0，90：10，80：20，70：30的质量配比生产乳固形物含量为12％的酸奶，对含有不同乳清蛋白比例的酸奶在贮藏过程中理化特性、乳酸菌总数的变化以及感官特性进行了比较分析。结果表明，WPC-3503代替10％-20％全脂奶粉生产酸奶时，在贮藏过程中可减缓pH值及酸度的变化速度，提高酸奶的黏度和保水率，改善感官特性，但对乳酸菌总数无明显的影响。     

改性乳清蛋白对凝固型酸奶品质及胆酸盐结合能力的影响

本研究利用酶结合苹果酸复合改性乳清蛋白（WPI-E+MA）,添加至凝固型酸奶,以期改良凝固型酸奶质构及胆盐结合能力。通过蛋白质浓度、持水力、游离巯基、粒径、粘弹性及胆酸盐结合能力等指标,评价WPIE+MA对凝固型酸奶品质、凝胶结构及胆酸盐结合能力的影响。结果表明,WPI-E+MA能够改善凝固型酸奶的持水力、表观粘度、剪切应力与粘弹性,8%添加量时达到最优;酸奶的凝胶网状交联结构因WPI-E+MA的添加变得更加致密、聚合度更高。脱氧胆酸钠（SDC）、胆酸钠（SC）、牛磺胆酸钠（STC）结合率均在8%的添加量达到最大值,结合能力良好。WPI-E+MA可有效改善凝固型凝固型酸奶的品质并显著提高胆酸盐结合能力。     

乙醇和芦丁稳定的乳清分离蛋白-大豆油预乳化液在低脂肉丸中的应用

研究乙醇和芦丁稳定的乳清分离蛋白-大豆油预乳化液作为脂肪替代物对低脂肉丸品质的影响。通过测定预乳化液的乳化稳定性、质构、黏度、粒径及流变特性,选择预乳化的最佳大豆油含量;以25%、50%、75%和100%比例对肉丸中的脂肪进行替代,以未替代的肉丸为对照组,通过测定蒸煮损失、色差、质构、气味、黏度、感官及抗氧化性,确定肉丸的最佳脂肪替代比例。结果表明：大豆油含量为72%的预乳化液乳化稳定性最好,凝胶形态良好且具有最大黏度;大豆油含量超过72%时,预乳化液的粒径增大,弹性模量下降;与对照组相比,脂肪替代比例为25%肉丸的蒸煮损失、色差（ΔE）、质构、黏度及感官得分均无显著变化,且氮氧化物、甲基类、硫化物等没有增加;贮藏9 d时,添加脂肪替代物的各组样品的硫代巴比妥酸反应物值显著低于未添加组（P＜0.05）。因此,含大豆油72%的乳清分离蛋白预乳化液作为脂肪替代物最佳,肉丸中脂肪替代比例25%效果最好。     

乳清蛋白粉对凝固型酸奶品质的影响

为提高凝固型酸奶的品质及安全性,将1%、1.5%、2%、2.5%、3%、4%、5%乳清蛋白粉(Whey protein powder,WPP)加入全脂乳粉中生产酸奶,以不添加WPP的凝固型酸奶为对照组,测定酸奶酸度、持水力(WHC)、脱水收缩敏感性(STS)、质构特性、流变学特性和微观结构变化,并进行感官评定,研究不同添加量乳清蛋白粉对凝固型酸奶品质特性的影响,以确定WPP最适添加量。结果表明:随着乳清蛋白粉添加量的增加,酸奶的滴定酸度、持水力、乳酸菌总数、硬度、胶着性、粘弹性、凝胶性逐渐增加,脱水收缩敏感性(STS)逐渐减小;当WPP添加量为2%时,酸奶的持水力、粘弹性都明显提升,STS明显降低,且具有较好的口感、更连续的网络结构,与对照组相比综合品质得到明显提高。     

Application of whey protein emulsion gel microparticles as fat replacers in low-fat yogurt: Applicability of vegetable oil as the oil phase

Low-fat, healthy yogurt is becoming increasingly favored by consumers. In the present study, whey protein emulsion gel microparticles were used to improve the quality of low-fat yogurt, and the effects of vegetable oil emulsion gel as a fat substitute on the qualities of low-fat yogurt were investigated, expecting to obtain healthier and even more excellent quality low-fat yogurt by applying a new method. First, emulsion gel microparticles were prepared, and then particle size distribution of emulsion gel and water holding capacity (WHC), textural properties, rheological properties, microstructure, storage stability, and sensory evaluation of yogurt were carried out. The results showed that yogurt with emulsion gel had significantly superior qualities than yogurt made with skim milk powder, with better WHC, textural properties, rheological properties, and storage stability. The average particle size of whey protein-vegetable oil emulsion gel microparticles was significantly larger than that of whey protein-milk fat emulsion gel microparticles, and the larger particle size affected the structural stability of yogurt. The WHC of yogurt made with whey protein-vegetable oil emulsion gel microparticles (V-EY) was lower (40.41%) than that of yogurt made with whey protein-milk fat emulsion gel microparticles (M-EY; 42.81%), and the texture results also showed that the hardness, consistency, and viscosity index of V-EY were inferior to these of M-EY, whereas no significant differences were found in the cohesiveness. Interestingly, the microstructure of V-EY was relatively flatter, with more and finer network branching. The whey separation between V-EY and M-EY also did not show significant differences during the 14 d of storage. Compared with yogurt made with whey protein, vegetable oil, and skim milk powder, the structure of V-EY remained relatively stable and had no cracks after 14 d of storage. The sensory evaluation results found that the total score of V-EY (62) was only lower than M-EY (65) and significantly higher than that of yogurt made with skim milk powder. The emulsion gel addition improved the sensory qualities of yogurt. Whey protein emulsion gel microparticles prepared from vegetable oil can be applied to low-fat yogurt to replace fat and improve texture and sensory defects associated with fat reduction.     

不同因素对乳清蛋白乳化凝胶特性的影响

探讨了葡萄糖酸-δ-内酯（GDL）、中性盐（NaCl、CaCl₂）以及增稠剂对乳清分离蛋白乳化凝胶强度、弹性以及保水性的影响。结果表明:GDL为0.6%、NaCl为1%、CaCl₂为0.25%、增稠剂卡拉胶为0.2%以及黄原胶为0.1%制备的乳化凝胶强度显著提高。GDL为0.4%、NaCl为0.75%、CaCl₂为0.25%、增稠剂卡拉胶为0.05%以及黄原胶为0.15%制备的乳化凝胶弹性显著提高。增稠剂卡拉胶为0.15%、黄原胶为0.1%所制备的乳化凝胶保水性显著提高。      

凝胶乳的制备及其理化特性的研究

为探究不同胶体制备的凝胶乳作为脂肪替代物使用时的理化特性,选用琼脂、结冷胶、明胶分别制备凝胶乳,探讨胶体种类、含量以及冷冻对凝胶乳理化性质的影响。结果表明:不同胶体制备的凝胶乳的理化特性有很大的差异,琼脂型凝胶乳45～25℃下形成固态,具有较硬的结构,结冷胶型凝胶乳凝固速率较快,两种胶体制备的凝胶乳加热至90℃时仍然保持固态,但冻-融稳定性较差;明胶型凝胶乳凝固温度较低,胶体含量增加能提高凝胶乳的冻-融稳定性,胶体含量为5%时,其冻-融后的持水力达到0. 983。可根据这些性质差异在不同的产品和加工过程中使用不同的凝胶乳替代动物脂肪。     

界面组成对乳化颗粒填充乳清蛋白凝胶强度及持水性的影响

考察了p H（3、7）、氯化钠浓度（50、200mmol/L）以及热处理（90℃、30min）对不同乳化剂（乳清分离蛋白、Tween20、Tween20+马铃薯蛋白水解物）制备O/W乳状液分层稳定性的影响。并以凝胶持水性和凝胶强度为指标,考察了p H和氯化钠浓度对上述不同界面组成的乳化颗粒填充乳清蛋白热诱导凝胶性质的影响。结果表明,以乳状液为溶剂制备的凝胶持水性与凝胶强度高于以水为溶剂制备的凝胶。加入一定量的氯化钠有助于乳状液凝胶持水性与凝胶强度的增加。研究表明,p H和盐浓度对乳状液填充凝胶强度均有影响,乳状液性质对乳状液填充凝胶强度和持水性有一定影响。      

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.     

Effect of monoglycerides and diglycerol-esters on viscoelasticity of heat-set whey protein emulsion gels

Summary Effects of small-molecule surfactants (emulsifiers) on the small-deformation viscoelastic properties of heat-set whey protein emulsion gels have been investigated using a controlled stress rheometer. The surfactants used in this investigation were the water-soluble diglycerol monolaurate (DGML) and diglycerol monooleate (DGMO), and the oil-soluble glycerol monooleate (GMO). The elastic modulus of the emulsion gel was found to decrease in the presence of a small amount of surfactant, but then to recover at higher surfactant concentrations. The initial reduction in modulus correlates with protein displacement from the oil droplet surface. The recovery of the storage and loss moduli at higher surfactant concentrations of DGML or DGMO may be due to the depletion flocculation of the emulsion prior to heat-treatment. However, for systems containing high content of GMO in the oil phase, the recovery of the moduli is probably owing mainly to the smaller average particle size. Effects of surface monolayer composition, droplet aggregation and average particle size were discussed. The behaviour obtained here was compared with results for previously investigated whey protein emulsion gel systems containing different emulsifiers.     

乳清浓缩蛋白WPC80凝胶工艺确定及其凝胶特性分析

以乳清浓缩蛋白(WPC80)为研究对象,分析了温度、时间、料液浓度、钙离子强度、乳糖浓度及pH值对其凝胶的影响,并通过测试样品凝胶特性。确定了WPC80凝胶的最佳工艺条件:配置质量分数为9%的WPC80溶液,室温400 r/min搅拌30 min至样品全部溶解;4℃储存10 h以上,便于蛋白溶解及水合;添加质量分数为0.12%的氯化钙;65℃,转速为80 r/min恒温水浴30 min;调节样品pH值为5.5;85℃水浴静置20 min形成凝胶。     

Effect of freezing on physical properties of whey protein emulsion films

The objective of this work was to study the effect of the freezing process on physical properties of whey protein emulsion films with different beeswax content dried at 5 °C. Thickness, microstructure, water vapour permeability, solubility in water, sorption isotherms and mechanical properties were measured in Control and Frozen films. The freezing process did not cause fractures or perforations in films, but films with beeswax showed a change in the appearance of the lipids after freezing. Only films with 40% of beeswax showed a significant increase in the water vapour permeability after freezing. The freezing process did not affect film solubility in water but produced small differences in the equilibrium moisture content values. In the puncture test, the freezing process increased puncture strength and deformation of films without beeswax but those parameters were not affected in films with beeswax. In tensile test, tensile strength and elastic modulus decreased, but elongation was not affected by freezing process. Principal component analysis accomplished an adequate condensation of the date grouping samples according to film formulation and treatment (Control and Frozen films). Indeed, the relationships of sample grouping and measured parameters were enlightened by principal component analysis. In conclusion, whey protein emulsion films were resistant to the freezing process (freezing, frozen storage and thawing) and could be a good alternative as a treatment to preserve the quality of frozen foods.