利用质构仪对不同类型干酪质地品质的研究

对目前市场上比较常见的干酪进行质地分析：分析了干酪的质地参数与其主要化学指标之间的关系．阐述了干酪的力学特性。结果表明，干酪类型的不同，主要取决于工艺过程以及其所含化学成分，例如水分含量不同．由此表现在TPA实验各项指标的差异上。     

Hydrocolloid gel particles: formation, characterization, and application

Hydrocolloid gel particles of micron and sub-micron size are particularly attractive for use in many applications in the food, agricultural, pharmaceutical, and chemical industries, due to their biocompatibility, perception as "natural" materials, and soft-solid texture. Industrial applications for such particles include uses as texturizers in confectionery and cosmetic products, slow-release encapsulation agents for flavors, nutrients, and pharmaceutical products, and thickeners in soups and sauces. Properties such as particle size, hardness, shape, texture, and molecular release rates can be important for individual applications. In addition, product formats will determine specific needs for physical form (e.g. dry or wet) and compatibility with other components. The diverse range of potential applications for hydrocolloid gel particles provide a driver for understanding-led tailoring of raw material and process conditions. This review introduces some of the materials that are used to form hydrocolloid gel particles and the corresponding gel formation mechanisms. One issue of importance in the production of hydrocolloid gel particles is the control of particle properties, such as release profiles, strength, and detectability within products. An alternative technique to traditional methods of hydrocolloid gel particle production is evaluated and a model for control of particle size, and subsequently other particle properties, is proposed. Key properties of hydrocolloid gel particles are identified and characterization methods for evaluating these properties are described.     

化学成分对车达再制干酪结构性质的研究

应用六种不同化学成分的干酪样品研究化学成分对再制干酪结构性质的影响。通过TPA实验分析硬度、脆性、粘性、弹性、胶粘性、耐咀性、回复性等质构特性参数,并根据多元回归分析法建立干酪化学组分和粘弹性之间的关系的预测模型。结果表明,水作为增塑剂,脂肪作为润滑剂,均增加了干酪的液体性质。相反,蛋白质使干酪的三维结构更加牢固,从而使干酪更多的表现出固体性质。     

高光谱成像在鱼肉品质无损检测中的研究进展

高光谱成像（hyperspectral imaging,HSI）技术作为一种无损、快速、准确的绿色分析技术在水产品品质检测方面得到了广泛应用。集图像与光谱技术优势于一体,HSI技术可同时检测实验样品的物理和几何特征（颜色、大小、形状和质地等）,还可以提供内部组成成分的化学和分子信息（水分、脂肪、蛋白及其他氢键物质）。本文主要综述了HSI技术在鱼肉品质快速检测方面的最新研究进展,主要涉及到鱼肉的化学组成、物理属性、微生物污染以及新鲜度等四大方面。同时对HSI技术在鱼肉检测中的应用研究进行了展望,以期开发适用于不同检测要求的在线HSI设备。     

The texture and taste of food in the brain

Oral texture is represented in the brain areas that represent taste, including the primary taste cortex, the orbitofrontal cortex, and the amygdala. Some neurons represent viscosity, and their responses correlate with the subjective thickness of a food. Other neurons represent fat in the mouth, and represent it by its texture not by its chemical composition, in that they also respond to paraffin oil and silicone in the mouth. The discovery has been made that these fat-responsive neurons encode the coefficient of sliding friction and not viscosity, and this opens the way for the development of new foods with the pleasant mouth feel of fat and with health-promoting designed nutritional properties. A few other neurons respond to free fatty acids (such as linoleic acid), do not respond to fat in the mouth, and may contribute to some “off” tastes in the mouth. Some other neurons code for astringency. Others neurons respond to other aspects of texture such as the crisp fresh texture of a slice of apple versus the same apple after blending. Different neurons respond to different combinations of these texture properties, oral temperature, taste, and in the orbitofrontal cortex to olfactory and visual properties of food. In the orbitofrontal cortex, the pleasantness and reward value of the food is represented, but the primary taste cortex represents taste and texture independently of value. These discoveries were made in macaques that have similar cortical brain areas for taste and texture processing as humans, and complementary human functional neuroimaging studies are described.     

面团发酵过程中小麦淀粉理化性质的变化

以小麦粉为原料,结合水洗和离心提取小麦淀粉,研究面团发酵过程中一次发酵、二次发酵和醒发工序对直链淀粉含量、溶解度、溶胀度、糊化特性和凝胶特性等理化性质的影响。试验结果表明:发酵后直链淀粉质量分数提高3.7%～8.18%;采用黏度速测仪(RVA,Rapid visco analyzer)分析醒发后小麦淀粉的峰值黏度、谷值黏度和最终黏度分别上升52 RVU、58.67 RVU和73.33 RVU;采用质构仪(TPA,Texture profile anal-ysis)对发酵过程小麦淀粉凝胶特性进行研究,发现醒发后凝胶特性有所改善,硬度提高48.60 g,弹性提高0.03,内聚性、回复性分别提高0.05、0.15。     

玉米淀粉及川明参添加量对川明参香肠品质的影响研究

以猪肉为主要原料,在传统四川风味香肠的加工工艺基础上,考察分别添加2%、4%、6%、8%、10%的玉米淀粉以及6%、8%、10%、12%、14%的川明参粉对川明参香肠的化学组成、质构特性和感官评价的影响。结果表明:淀粉及川明参粉添加量对香肠质构特性中的硬度、弹性、凝胶性影响显著(P<0.05),对品质特性中的持水率和蒸煮率影响显著(P<0.05),对蛋白质含量、pH影响不显著(P>0.05)。当玉米淀粉添加量为6%、川明参粉添加量为10%时,香肠的质构和感官品质较好,为香肠的标准化和工业化生产提供了理论参考。     

Food-grade nanoemulsions: formulation, fabrication, properties, performance, biological fate, and potential toxicity

Nanoemulsions fabricated from food-grade ingredients are being increasingly utilized in the food industry to encapsulate, protect, and deliver lipophilic functional components, such as biologically-active lipids (e.g., ω-3 fatty acids, conjugated linoleic acid) and oil-soluble flavors, vitamins, preservatives, and nutraceuticals. The small size of the particles in nanoemulsions (r<100 nm) means that they have a number of potential advantages over conventional emulsions-higher stability to droplet aggregation and gravitational separation, high optical clarity, ability to modulate product texture, and, increased bioavailability of lipophilic components. On the other hand, there may also be some risks associated with the oral ingestion of nanoemulsions, such as their ability to change the biological fate of bioactive components within the gastrointestinal tract and the potential toxicity of some of the components used in their fabrication. This review article provides an overview of the current status of nanoemulsion formulation, fabrication, properties, applications, biological fate, and potential toxicity with emphasis on systems suitable for utilization within the food and beverage industry.     

TEXTURE OF TABLE OLIVES AND PIMENTOS

Mechanical and chemical methods applied to quantifying the texture of table olives and pimientos are reviewed, and examples are given of studies on factors affecting the texture of these products (such as fruit maturity and processing) in which these methods have been used. The four instruments found applicable to olives are: Christel Texturometer, FFL Penetrometer, IG Texturometer and Kramer Shear Press (compression and shear/compression cells). The latter has also been used with pimientos. Advantages and disadvantages of each are discussed. Additional work is needed on correlating the mechanical tests with sensory evaluation. The chemical methods involve quantification of pectic substances and their degradation products.     

偏最小二乘回归法分析藏鸡胸肉质地特性

为揭示藏鸡肉独特的质地特性,探寻鸡胸肉质地特性与其化学成分和微观结构的关联性,本研究对5 种不同的鸡肉原料（藏鸡、与藏鸡同日龄或体质量接近的雪山草鸡、淘汰蛋鸡（对照）和白羽肉鸡（对照））进行剪切力、质地剖面分析（texture profile analysis,TPA）和应力松弛特性测定,并将上述质地特性分析结果和鸡肉的基本化学指标（水分质量分数、粗脂肪质量分数、粗蛋白质量分数、胶原蛋白质量分数、pH值）、组织学特征（肌纤维直径和密度）进行关联性分析,利用偏最小二乘回归（partial least squares regression,PLSR）法揭示影响鸡肉质地特征的显著因素。结果发现,利用PLSR能够将多个与肌肉质地特性相关的化学指标量化为鸡肉品质综合评价指标,其中剪切力的预测模型更适合预测鸡肉的质地特性。该模型的R2X为0.621,R2Y为0.739,模型拟合效果较好。Q2cum在0.6以上,说明该模型的可预测性能够被接受。载荷图显示剪切力与pH值、总胶原蛋白质量分数和肌纤维直径呈显著正相关（P＜0.05）,而与粗脂肪质量分数、可溶性胶原蛋白质量分数、胶原蛋白溶解性和肌纤维密度呈显著负相关（P＜0.05）。贡献度评价结果显示,胶原蛋白溶解性、肌纤维密度、可溶性胶原蛋白质量分数和肌纤维直径4 个指标均在模型中贡献显著。本研究可为从质地特性角度揭示藏鸡胸肉特有“咀嚼感”提供数据支持,并为丰富肉的力学特性研究提供一定的理论参考。     

EFFECTS OF FUNCTIONAL DAIRY BASED PROTEINS ON NONFAT YOGURT QUALITY

Production of nonfat yogurt demands a careful control of quality parameters. It is common to use skim milk powder (SMP) to increase the total solid content of nonfat yogurt, but some functional dairy-based proteins, such as casein/caseinates and whey proteins, may improve the quality of nonfat yogurt.
The objectives of this study were to use whey protein isolate (WPI), sodium caseinate (NaCn) and yogurt texture improver (TI) in nonfat yogurt manufacture as an alternative for SMP, and to compare their potential influences on the physical, chemical and microbial properties of nonfat yogurts over a 12-day storage. All dry ingredients were added at 1% (w/v) concentration to yogurt milk. Yogurts differed from each other with different hardness values. Acetaldehyde contents of yogurts were in the range of 35–43 ppm. The acetaldehyde content of all yogurt types decreased during storage. The control yogurt had the most tyrosine content, and the WPI-fortified yogurt had the least. Using different dry dairy ingredients did not affect the numbers of starter cultures. In addition, no significant differences were observed among yogurt types regarding their mineral composition.

PRACTICAL APPLICATIONS

Functional dry dairy ingredients can be used to increase the total solid content of nonfat yogurt instead of using skim milk powder (SMP) or evaporation. Their high protein content, water-binding capacity, texture improvement properties and health benefits make these proteins suited for use in nonfat yogurts. This study compares the possible effects of using whey protein isolate (WPI), sodium caseinate (NaCn) and yogurt texture improver (TI) as an alternative for SMP on the physical, chemical and microbial properties of nonfat yogurts. It was found that substitution of SMP for WPI, NaCn and TI at the level of 1% affected the physical, chemical and microbial properties of nonfat yogurt.     

墨绿色钠长石玉的初步研究

以墨绿色钠长石玉样品为研究对象,采用常规的宝石学测试、偏光显微镜、电子探针、X射线粉末衍射等分析方法,从宝石学特征、矿物组成、结构特征、有序度等方面,对该钠长石玉进行了较全面的研究。结果表明,墨绿色钠长石玉的折射率为1.53(点测),密度约为2.64g/cm3;其薄片中矿物晶体的形态主要呈半自形-他形粒状、短柱状和纤维状,结构主要有糜棱结构和纤维粒状变晶结构,主要矿物组成为钠长石和角闪石。电子探针的化学成分分析显示,样品中钠长石的An值小于0.006,说明钠长石的成分很纯;所含的角闪石种类主要为镁钠铁闪石。由X射线粉末衍射峰数据计算出钠长石的结构有序度极接近于1,其为完全有序的低钠长石,形成温度低于300℃。本文填补了钠长石玉研究中的一些空缺,为钠长石玉的系统性和综合性研究提供一些有意义的理论成果。     

The science of plant-based foods: Constructing next-generation meat,fish, milk,and egg analogs

Consumers are increasingly demanding foods that are more ethical, sustainable and nutritious to improve the health of themselves and the planet. The food industry is currently undergoing a revolution, as both small and large companies pivot toward the creation of a new generation of plant-based products to meet this consumer demand. In particular, there is an emphasis on the production of plant-based foods that mimic those that omnivores are familiar with, such as meat, fish, egg, milk, and their products. The main challenge in this area is to simulate the desirable appearance, texture, flavor, mouthfeel, and functionality of these products using ingredients that are isolated entirely from botanical sources, such as proteins, carbohydrates, and lipids. The molecular, chemical, and physical properties of plant-derived ingredients are usually very different from those of animal-derived ones. It is therefore critical to understand the fundamental properties of plant-derived ingredients and how they can be assembled into structures resembling those found in animal products. This review article provides an overview of the current status of the scientific understanding of plant-based foods and highlights areas where further research is required. In particular, it focuses on the chemical, physical, and functional properties of plant-derived ingredients; the processing operations that can be used to convert these ingredients into food products; and, the science behind the formulation of vegan meat, fish, eggs, and milk alternatives.     

小分子糖对淀粉性质的影响研究进展

小分子糖是一类分子量较低的糖类,主要包括单糖、二糖以及其它低聚合度寡糖。小分子糖可用于提供甜味、改善食品质构、优化食品的加工适应性等,通常作为食品添加剂应用于食品领域中。此外,部分小分子糖具有独特生理功能,可用于调控食品营养品质。淀粉是食品中最常见的主食组分,淀粉及其改性衍生物也作为食品配料,应用于酱料、乳制品、饮料以及肉制品等食品品类中。小分子糖与淀粉的复合体系在食品中应用十分广泛,其添加对天然淀粉性质具有重要影响,在调控淀粉基食品品质中起到重要作用。本文综述了食品中常见的小分子糖及其对淀粉主要理化性质（凝胶质构、透明度、凝沉性、糊化、冻融稳定性、老化、消化等）的影响,重点描述了不同类型及添加量的小分子糖对不同来源淀粉性质的影响规律,旨在为小分子糖在淀粉基食品中的应用提供参考。     

PROTEIN-CARBOHYDRATE INTERACTIONS AT ELEVATED TEMPERATURES*

A series of protein types have been characterized with respect to their interaction with low dextrose equivalent corn starch hydrolysates. From an assessment of the chemical modification of selected functional groups, classical denaturation studies, gel filtration and precipitation with tri-chloro-acetic acid, the partial basis for molecular interaction has been elucidated. Although all proteins under investigation were prominent components of a variety of food systems, particular emphasis was placed on the behavior of β-lactoglobulin and selected soy fractions. Results from the modification and denaturation studies indicated that several factors are required to account for the extent of interaction, but that the predominant effect appears to be non-covalent in nature. In the case of commercial soy proteins, considerable polydispereity was detected prior to the interaction - much of which was doubtless induced during isolation. Many such fragments of this preparation showed self-interacting properties, which could provide a basis for texture in the reported system. The starch hydrolysates appear to exhibit a protective effect against excessive protein aggregation, which could have significance in retention of nutritional value during food processing.     

Hybrid mixed media nonwovens composed of macrofibers and microfibers. Part I: three-layer segmented pie configuration

Nonwoven fabrics, composed of microdenier fibers, can be easily created by using splittable bicomponents such as segmented pie. Hydroentangling has been shown as a very effective method for mechanically splitting these fibers. Such structures are known to form a densely packed nonwoven fabric with concomitant consequences in low porosity and tear strength. It is not, therefore, uncommon to insert a reinforcing scrim as a “rip-stop” mechanism in the middle of such structures to improve their properties, especially tear resistance. Instead, we propose a hybrid structure where the middle portion consists of solid homocomponent fibers, made from the same polymer as one of the components used in the bicomponent fibers, produced simultaneously during web formation, without causing noticeable changes in the fabrics’ overall texture. We report on the production and properties of fabrics composed entirely of bicomponent segmented pie fibers as well as our hybrid fabrics arranged in a three-layer configuration.     

乳蛋白体系流变学研究进展

乳蛋白体系的流变学特性与乳制品的质构和生产工艺关系密切。近年来,基于乳蛋白组分在食品中的重要性,食品科学家对乳蛋白体系的流变学性质进行了深入研究。文章就乳清蛋白和酪蛋白的凝胶特性以及乳清蛋白溶液的粘度流变特性作了介绍。     

Classification of Kashar Cheeses Based on Their Chemical,Color and Instrumental Textural Characteristics Using Principal Component and Hierarchical Cluster Analysis

Principal component analysis and hierarchical cluster analysis were applied to investigate physicochemical and instrumental textural properties of fresh kashar cheese. Four different principal components sufficiently explained the variability in the cheese samples. In addition, hierarchical cluster analysis was performed to group the kashar cheese samples regarding physicochemical and instrumental textural properties. Instrumental textural properties indicated greater variability than chemical composition of cheese samples. Principal component analysis revealed that color parameters were positively correlated with textural and chemical parameters. The results of this study revealed that other parameters rather than chemical composition would be effective on the instrumental textural properties. It was proved that principal component analysis was a very effective statistical tool to determine quality of cheese samples. According to the principal component analysis and hierarchical cluster analysis results, the attributes defining the kashar cheese samples were determined to be primarily the texture profile analysis parameters.     

花生牦牛肉酱配方技术的研究

研究主要目的是探讨酱体、花生添加量、牦牛肉添加量和用油量对花生牦牛肉酱感官、质构和化学指标的影响,并筛选出色香味俱佳的花生牦牛肉酱配方。研究共进行了三个试验,分别探讨了酱体和花生添加量、花生和牦牛肉添加量及植物油添加量对花生牦牛肉酱感官、质构和化学成分的影响。研究结果发现:酱体用量为35%,花生添加量为25%时,牦牛肉酱感官最好,硬度、稠度、内部的粘着性最大;花生添加量为25%,牦牛肉添加量为5%时,花生牦牛肉酱感官指标得分最高;菜籽油用量为31%时,酱体流动性和口感较好。试验花生牦牛肉酱的最佳配方为酱体用量35%、花生25%、牦牛肉5%、辅料4%、菜油31%。酱体成分、花生、牦牛肉和植物油使用量均影响花生牦牛肉酱感官、质构和化学成分。     

添加豆乳对Mozzarella混合干酪微观结构、功能和质构特性的影响

目的考察添加豆乳对Mozzarella混合干酪的微观结构、功能和质构特性的影响,为进一步增加豆乳的添加比例及优化混合干酪的生产工艺提供理论基础。方法参考传统Mozzarella干酪的生产工艺,按牛乳中豆乳的添加量分别为5%、10%、15%、20%、25%(V:V)制作混合干酪样品,以纯干酪为对照,采用化学分析方法对混合干酪样品的水分、脂肪和蛋白质含量进行了检测;通过扫描电子显微镜对干酪样品的微观结构进行了观察,并对Mozzarella干酪的两个重要功能特性,拉伸性和融化性进行测定;最后,利用质构仪对干酪样品包括硬度,弹性和粘附性等质构特性进行表征。结果和纯牛乳干酪对比,添加了豆乳的于酪具有更多的水分,更少的蛋白质和脂肪。5%的豆乳添加量,也会导致蛋白胶束变粗,拉伸长度下降。而无论豆乳添加总量是多少,豆乳含量的添加对干酪的融化直径都没有显著性影响。豆乳的添加,会造成硬度和弹性的降低,粘附性增大,添加量10%及以上含量的豆乳,效果更为显著。本试验对干酪样品的后熟进行了研究,除了微观结构会发生变化外,功能和质构特性的变化均不明显。结论豆乳的添加主要对干酪的拉伸性和微观结构产生重要的影响,这对后期的工艺优化具有重要的启发意义。