杂粮复合酸奶的感官评价与理化性质研究

以大豆为基础原料,添加杂粮糊液等成分,经过发酵制成了一种杂粮复合酸奶,并对酸奶样品进行蛋白质含量、p H值、持水性、流变学特性和质构性质等检测。同时,研究剪切速率对酸奶样品黏度的影响,以及杂粮糊液添加比例对酸奶的质构及感观性质的影响。结果表明,随着杂粮糊液的添加比例的提高,酸奶样品的表观黏度明显增加;7种酸奶的8项评价指标组间有显著差异(p0.05)。酸奶破裂强度与硬度相关性极显著(p0.01),胶黏性与光滑感相关性极显著(p0.01);质构硬度与感官硬度和适口性的相关性显著(p0.05),质构弹性与感官光滑感和适口性相关性显著(p0.05)。其中,杂粮糊液添加比例为11%(质量分数)的酸奶样品,综合评分最高,口感和风味最好。     

酶法制备天然牛奶香精的工艺条件与应用研究

奶油酶解增香的研究主要是以奶油或无水奶油为原料,利用不同来源的脂肪酶对乳脂肪进行适当酶解,通过控制酶解程度得到具有不同香气特征的酶解产物。本文在奶油酶解工艺单因素研究与特征风味组分研究的基础上,对酶解奶油产物进行风味修饰得到自制天然牛奶香精,并对其与市售商品天然牛奶香精、合成牛奶香精样品在复原乳中的感官品质进行比较评定。研究结果表明添加相同比例的商品天然牛奶香精和自制天然牛奶香精的脱脂复原乳样品的感官评定结果没有差异,即自制天然牛奶香精与商品天然牛奶香精在脱脂复原乳中的感官品质基本相同。此外,感官评价结果还表明添加有合成牛奶香精的复原乳样品中奶香味过于冲鼻且留香持久性较差,感官品质相对一般。     

复配乳化剂HLB值对稀奶油脂肪聚结及结晶的影响

将单,双甘油脂肪酸酯与蔗糖酯按一定比例复配成不同亲水亲油平衡（hydrophile lipophilic balance,HLB）值的乳化剂,研究复配乳化剂HLB值对稀奶油脂肪聚结及结晶影响,并对其乳液性质及打发性质进行表征。结果表明,随着复配乳化剂HLB值的增大,乳液粒径增大且表观黏度升高进而使搅打时间延长;热力学及Avrami等温结晶动力学结果表明,复配乳化剂HLB值为10时,高熔点乳脂熔融温度改善显著,并且结晶速率最快;HLB值为8～10时打发性较好,乳清泄漏率较低,涂抹性较佳。因此,复配乳化剂HLB值应控制在8～10,此时更适用于高品质裱花稀奶油的工业生产。     

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。     

一种基于口腔软摩擦学的奶茶顺滑特性评价模型

该文系统研究了奶茶主要原料植脂末（5.00~100.00 g）、冰块（5.00~200.00 g）和糖浆（0~12.00% m/m）添加量对奶茶顺滑特性，包括粒径分布、流变特性、感官评价及口腔软摩擦学的影响，通过补充和优化现有标准，成功建立了特异性针对奶茶口感顺滑度的感官评价新标准。结果表明奶植脂末添加量与奶茶的粒径呈负相关，与粘度呈正相关。当植脂末添加量为60.00 g时，奶茶的平均粒径为0.66 μm。通过对样品进行口腔软摩擦学分析，建立了奶茶口感顺滑度的预测模型和评判标准，即只有当口腔软摩擦学曲线同时满足K2∈(-0.23, -0.05)和vR2<40.00 mm/s时，奶茶表现出较好的顺滑特性，否则奶茶口感淡薄或厚重，口感顺滑度差。因此，该口腔软摩擦模型能够评价不同配方奶茶的顺滑特性，在快速评价流体食品的口感顺滑方面具有实际应用前景。     

乳脂肪球膜的特性、开发及在模拟母乳脂肪球结构中的应用

乳脂肪球膜（milk fat globule membrane,MFGM）是包裹在天然乳脂肪球外部的3 层膜状结构,然而牛乳基和大豆基婴儿配方奶粉缺少MFGM,脂肪球结构与母乳存在较大差异,因此添加外源MFGM以及制备与母乳脂肪球结构接近的婴儿配方奶粉成为了近期的研究焦点。本文综述了MFGM的相关特性和生产开发途径,以及牛乳MFGM在仿母乳脂肪球结构乳液和婴儿配方奶粉中的应用。体外模拟婴儿胃肠道消化实验以及啮齿动物体内实验结果表明,仿母乳脂肪球结构乳液和婴儿配方奶粉能够促进婴儿脂肪消化并且改善脂质代谢过程。     

稻米油对涂抹再制干酪微观结构的影响

研究稻米油替代乳脂肪对涂抹再制干酪微观结构的影响。以切达干酪为原料,添加不同比例稻米油制备涂抹再制干酪,测定不同稻米油比例样品的微观结构和脂肪酸含量。结果表明,稻米油替代乳脂肪可以增加再制干酪产品长链脂肪酸,减少其短链脂肪酸、中链脂肪酸比例。稻米油替代对涂抹再制干酪的脂肪酸饱和度和链长的影响,导致再制干酪体系中脂肪球大小和分布的差异。对照组脂肪球小而分布均匀,植物油替代比例增加导致更大的脂肪球,通过微观结构观察,稻米油替代比例增大至50%时,开始出现较大直径且分布不均匀的脂肪球。因此,稻米油替代比例应控制在50%以下较为适宜。     

母乳与山羊乳功能性不饱和脂肪酸及脂肪球微观结构的比较

本研究采用气相色谱-质谱法及显微观察手段分析不同泌乳期母乳与山羊乳常乳中主要功能性不饱和脂肪酸相对含量、理化性质和微观结构,旨在为母乳脂质的研究及以山羊乳为基质的婴幼儿配方奶粉母乳化提供一定的数据支撑。结果表明：母乳初乳、过渡乳、成熟乳脂肪质量浓度显著增加（P＜0.05）,分别为（26.7±3.6）、（33.7±4.6）g/L和（41.0±6.8）g/L;山羊乳脂肪质量浓度（（42.1±4.3）g/L）显著高于母乳初乳和过渡乳（P＜0.05）。但母乳中主要功能性脂肪酸相对含量显著高于山羊乳,尤其是亚油酸相对含量（过渡乳中最低,为19.76%）显著高于山羊乳（4.43%）（P＜0.05）。在物理特性方面,母乳初乳脂肪球具有最大体积平均粒径（（5.63±0.51）μm）和最低ζ电位（（－5.72±0.21）mV）,而山羊乳脂肪球体积平均粒径和ζ电位分别为（3.63±0.31）μm、（－13.69±0.27）mV。脂肪球粒径、ζ电位与脂肪质量浓度显著相关（P＜0.05）。不同泌乳阶段母乳中主要功能性脂肪酸相对含量及脂肪球物理特性不同,与山羊乳差异明显。本实验结果可进一步用于母乳及山羊乳制品的研究。     

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。     

淀粉基脂肪模拟物的性质及代脂研究

以玉米淀粉为原料，在不同条件下对其进行酸水解制取脂肪模拟物。并对得到的不同DE值（糖液中的还原糖含量占干物质百分率）的玉米淀粉基脂肪模拟物进行性质研究。扫描电镜观察结果表明，样品具有2μm-6μm的粒径；x-粉末衍射图表明，样品保留了A型特征峰。以其中一种脂肪模拟物为代表，作为脂肪替代品加到奶油中进行代脂研究，结果表明所制得的玉米淀粉水解产物可作为脂肪模拟物用于奶油中。     

Fatty versus creamy sensations for custard desserts,white sauces,and mayonnaises

Perceived fattiness and creaminess plus other texture and flavor attributes were assessed for a group of vanilla custard desserts, white sauces, and mayonnaises that differed widely in ingredients, fat content (0–72%), and consumption temperatures. In addition, the foods were measured instrumentally with regard to their lubricative properties, infra-red reflectance and turbidity of rinse water. Despite the variety in foods, fat content showed strong correlations with the instrumental measures, and perceived fattiness, and weaker but still significant correlations with creamy mouth and after-feel. Friction and infra-red reflectance demonstrated that properties of the surface of the oral food bolus are important for fat-related attributes via mechanisms such as lubrication. Turbidity of rinse water suggested that properties of the bulk of the food bolus are important as well. Creamy after-feel related less well to instrumental measures, fat content and other sensory attributes suggesting that the creaminess of oral coatings is not only affected by fat but also by other unknown properties.     

Effect of emulsifier type on sensory properties of oil-in-water emulsions

This work investigates the fundamental properties of emulsifiers that may contribute to the fat-associated sensory attributes of emulsions. Model oil-in-water emulsions were prepared with 0, 12, 24, 36 and 48% oil and emulsified with seven different emulsifiers; two proteins; sodium caseinate and whey protein, and five different sucrose esters. Emulsions were rated for perceived ‘fat content’, ‘creaminess’ and ‘thickness’ on nine-point category scales. Instrumental measurements of particle size, viscosity, thin film drainage, surface dilational modulus and interfacial tension were made. The sensory results indicate significant main and interactive effects of fat level and emulsifier type. At higher fat levels, emulsions prepared with sodium caseinate and whey protein emulsifiers had higher viscosities and higher sensory scores than those prepared with the sucrose esters. Results indicate that emulsifier type has a significant effect on the sensory properties of oil-in-water emulsions, and relationships between instrumental and sensory measures suggest that this may be due to the interfacial properties of emulsifiers at the oil–water interface. © 1998 SCI.     

Influence of emulsion composition on lubrication capacity and texture perception

The role of fat content and type of surfactant for oral friction processes and texture perception of oil-in-water emulsions was assessed. Emulsions at 22% and 33% fat content containing either sodium caseinate or a sucrose ester as emulsifier were compared with viscosity-adapted aqueous solutions of dextran using both sensory evaluation and friction coefficient measurements on a tongue-palate contact model. The impact of saliva on the emulsion droplet size distribution was studied using tribology, differential interference contrast microscopy and light diffraction measurements. Emulsions at 33% and the corresponding iso-viscous aqueous solutions were discriminated in the sensory experiment whereas emulsions at 22% were not. Friction was significantly different for emulsions at 33% and the corresponding iso-viscous aqueous solutions. The difference was not significant for emulsions with 22% fat level when compared with the iso-viscous aqueous solutions. Saliva significantly decreased the friction coefficient of emulsions depending on the surfactant and amount of fat used.     

The effect of using a whey protein fat replacer on textural and sensory characteristics of low-fat vanilla ice cream

The purpose of this research was to evaluate the texture of regular (12%), low fat (6%), and fat-free vanilla (0.5%) ice creams by sensory and instrumental analyses. The low fat and fat free ice cream were prepared using a whey protein based fat replacer (Simplesse ^® 100) as the fat replacement ingredient. Two processing trials with continuous commercial-like process conditions were undertaken. Sensory analyses disclosed that ice creams containing 6% of fat replacer in place of or with milk fat had no demonstrable effect on vanillin flavour. While the sensory attributes of the low fat samples were comparable to the regular vanilla ice cream, the trained sensory panel rated the fat free ice cream to have lower viscosity, smoothness and mouth coating properties. Instrumentally determined apparent viscosity data supported the sensory data. Compared with the fat replacer, milk fat significantly increased the fresh milk and cream flavours of the ice cream. Results emphasized the importance of fat as a flavour modifier and the improvement of texture by addition of Simplesse ^® 100.     

Textural perception of liquid emulsions: Role of oil content,oil viscosity and emulsion viscosity

This work describes a study on the in-mouth textural perception of thickened liquid oil-in-water emulsions. The variables studied are oil content, oil viscosity, and the concentration of polysaccharide thickener. Gum arabic was chosen as the thickener because of the nearly Newtonian behavior of its solutions and special care was taken to suppress aroma clues. Based on the experimental results and findings from previous studies, this work shows that the emulsion droplets influence textural sensory perception of liquid emulsions by three main mechanisms, each of which relate to changes in specific sensory attributes, and none of which were found to be significantly dependent on the viscosity of the oil: 1) by increasing the viscosity, 2) by becoming incorporated in the mucous oral coating, and 3) by spreading oil at the oral surfaces. Based on these results, the possibility for replacement of emulsified fat by a polysaccharide thickener is evaluated.     

Predicting the Texture of Liquid and Melting Semi-Solid Foods

Magnitude estimations of a variety of dairy foods show that sensory assessments scores of “creaminess” can be predicted from scores of “smoothness” and “thickness”. The empirical equation found for these predictions is very close to that found earlier for model solutions. Assessments of “smoothness” can be related to instrumental measurements of contact friction. Assessments of “thickness” for melting foods are related to estimates of shear stresses in the mouth generated during the melting of foods.     

Physical Stability Assessment and Sensory Optimization of a Dairy-Free Emulsion Using Response Surface Methodology

ABSTRACT: Desserts made with soy cream, which are oil-in-water emulsions, are widely consumed by lactose-intolerant individuals in Brazil. In this regard, this study aimed at using response surface methodology (RSM) to optimize the sensory attributes of a soy-based emulsion over a range of pink guava juice (GJ: 22% to 32%) and soy protein (SP: 1% to 3%). WHC and backscattering were analyzed after 72 h of storage at 7 °C. Furthermore, a rating test was performed to determine the degree of liking of color, taste, creaminess, appearance, and overall acceptability. The data showed that the samples were stable against gravity and storage. The models developed by RSM adequately described the creaminess, taste, and appearance of the emulsions. The response surface of the desirability function was used successfully in the optimization of the sensory properties of dairy-free emulsions, suggesting that a product with 30.35% GJ and 3% SP was the best combination of these components. The optimized sample presented suitable sensory properties, in addition to being a source of dietary fiber, iron, copper, and ascorbic acid.