不同乳头对食品舌面触觉感受差异性研究

以人的舌面为研究对象,应用心理物理学的量值估计法比较舌面不同区域对非味觉刺激化合物的感受能力,并测量菌状乳头、丝状乳头密集区域及手指的触觉阈值,结果表明:2种乳头密集区域对非味觉刺激化合物的感受能力存在显著差异(p＜0.01),菌状乳头密集区域最敏感,丝状乳头密集区域与手指触觉阈值相似,说明舌面不同乳头在食物触觉感受中承担着不同的角色.     

人工甜味味觉传感器的研究进展

人工味觉传感器按味觉响应原理不同可分为电位型传感器和伏安型传感器,是近年来兴起的一种用来检测味觉的电化学生物传感器形式。本文从味觉的仿生学角度介绍了人工味觉传感器的原理,通过味觉检测研究方法阐述了其构建方法及研究现状。主要概括了电位型味觉传感器在甜味检测方面的应用,包括PVC薄膜传感器对蔗糖的高敏感度选择性检测以及各类传感器对软饮料等甜味物质的检测。目前的实验研究表明,利用电化学生物传感器对甜味物质具有一定的选择性识别,且操作简单快速,但在准确度上还有待提高,同时人工味觉的仿生表达还需要更深入的研究。     

评估酵母活性方法的综合研究

本文对评估酵母活性的方法进行了研究。主要分成三类，即细胞染色法，细胞培养法和细胞生理状况测定法。文中详细阐述了细胞生理状况测定法中的肝糖含量测定法、蛋白酶A法、胞内pH法、累加的酸化力测定法，为研究酵母活性的细微区别提供了合理、精确、简捷的方法。     

食品微生物检验菌落总数测定方法的效果分析

目的:分析研究食品微生物检验菌落总数测定方法的测定效果。方法:选取本疾控中心接收的220份食品样品,对其采取3种方法进行检测,包括平板菌落计数法、TCT培养基法以及菌落总数测定法,对其检验结果进行对比分析。结果:平板菌落计数法的不合格率为9.1%,菌落总数测定法的不合格率为8.2%,TCT培养基法的不合格率为10%,3种检测方法结果之间的差异不具有统计学意义(P0.05)。结论:食品微生物检验采取平板菌落计数法、TCT培养基法以及菌落总数测定法这3种方法均可以取得相对比较高的准确性,可以按照具体情况选择适宜的检验方法。     

大豆异黄酮检测及四标样快速测定法研究

介绍大豆异黄酮化学组成和几种常用检测方法,以及四标样快速测定法的研究。这些方 法都有其优点和局限,四标样快速测定法以其准确、快速、简单的特点,满足工业生产过程 中检测的需要。     

耐碱汗渍色牢度快速测定法的探索

介绍了耐碱汗渍色牢度的快速测定法1(烘箱法)和快速测定法2(熨斗法),这两种测定法与国标GB3922-83耐汗渍色牢度中的耐碱汗渍牢度相比,快速法1缩短时间3h,快速法2只需2—3min,测定结果基本都在同一级差允许范围内,可供有关单位参考使用。     

淀粉含量快速测定法的探讨

淀粉含量的测定方法很多，有酸解法、酶一比色法、旋光法、快速法等。本文阐述了快速测定法测定淀粉含量的原理、设备、试剂及测定方法步骤，并和酸解法进行比较，结果表明：二者不存在系统误差，快速测定法的精度高于酸解法且操作简便，所用试剂较少，时间较快，方法可靠。     

浅谈中国菜肴的“风味”——物理味觉

物理味觉、化学味觉、心理味觉是构成中国菜肴风味的三大要素,而物理味觉就是食物进入口腔的感觉,也就是口感。一盘菜肴人们喜欢不喜欢吃,于口感有着极大的关系,对一些菜来讲,口感是菜肴的灵魂。     

纸及纸板边压强度测定法的分析比较

本文介绍了加工瓦楞纸箱用的瓦楞原纸和箱纸板边压强度的意义,并对其两种测定法RCT法和SCT法进行了分析比较,同时还介绍了RCT和SCT测定结果间的关系。     

牛乳体细胞数的检测方法

讨论了体细胞数与乳腺炎的关系以及体细胞数对牛乳成分及产奶量损失的影响。主要介绍了4种常用的体细胞数的检测方法，即加利福尼亚细胞数测定法(CMT)，威斯康辛乳腺炎试验(WMT)，电子体细胞计数法(DHI)和直接镜检法(CMSCC)。     

FOOD TEXTURE AND TASTE: A REVIEW

The subjective measurement of food texture and the objective measurement based on a rheological model are described to clarify the relationship between texture and taste. The authors suggest that the most important sensory property is texture in foods which have relatively low flavor intensity. Additionally, from the fact that the multidimensional evaluation of palatability of foods is strongly influenced by properties requiring physical measurement, they propose the introduction of a new concept, physical taste, for making effective evaluations of food palatability. More quantitative texture studies related to food quality are required as well as research on the traditional four or five basic tastes.     

Methodological approaches to assess tactile sensitivity in the food context—A scoping review

In contrast to taste sensitivity, the assessment of texture or tactile sensitivity has received relatively little attention in the food context. Texture plays an important role in food preferences and food intake, and individual differences make it important to understand physiological drivers of perception as tactile sensitivity. The multi-dimensional and dynamic aspects of texture perception suggest there is not one single method that can explain individual differences. This scoping review aims to systematically map methods assessing tactile sensitivity, in the context of food, highlighting differences in approach and implementation. Eligibility criteria included papers describing methods to assess individual differences in tactile sensitivity, that involved human participants and the context was relevant to food behavior. Sources are peer-reviewed publications of original research in English. In mapping the methods, we assessed how they relate to food texture parameters (mechanical, geometrical, and surface) and the dynamics of breaking down (touch with hand, first bite/sip, oral processing, residual or after-swallowing sensations). We also review other parameters associated (oral processing, preference, diet and food intake behavior). The literature in this relatively young area is still very fragmented and it is difficult to have a clear picture regarding best practices or recommendations for the measurement of tactile sensitivity in the food context. Future studies should aim to methodological harmonization for application in the food behavior area, with a design of experiment combining different aspects of tactile sensitivity to food, focusing on the thresholds and perceived intensity of textural parameters as well as affective and behavioral responses, and covering the whole spectrum of tactile texture perception (mechanical, geometrics, and surface), including the dynamics of perception.     

基于纳米金光学性质检测脂肪酶活性的研究进展

脂肪酶是食品工业广泛应用的酶制剂, 其活性大小对食品品质有重要影响, 因此对其活力测定成为食品检测中不可或缺的一部分。脂肪酶常见的测定方法有滴定法、皂铜比色法、平板法等, 但这些方法往往存在操作复杂、灵敏度不足、测量误差较大的缺点, 而基于纳米金光学性质检测脂肪酶具有简单快速、灵敏度高、特异性强、操作简单等优点, 是一种良好的测定方法。本文主要从纳米金的光学性质和测定的原理、基于纳米金的光学特性检测脂肪酶的方法及未来发展3个方面对纳米金在测定脂肪酶活性方面的研究进展进行评述。目前, 使用纳米金检测脂肪酶活性仍然存在很多问题, 通过总结近年来脂肪酶活性的检测方法, 希望能对未来脂肪酶活性快速、灵敏检测起到一定的推进作用。     

Lowering barriers to plant-based diets: The effect of human and non-human animal self-similarity on meat avoidance intent and sensory food satisfaction

The connection between plant-based diets and compassion is intuitive. Prior research has demonstrated that food of ethical origin subjectively tastes better to consumers who embrace ethical values. Since meat avoiders generally internalize the values associated with the avoidance of animal-derived products, higher levels of compassion are expected to enhance the subjective taste of meatless food choices, which has implications for lowering barriers to the adoption of vegetarian diets.Three experimental laboratory studies demonstrate that compassion improves the subjective taste of meatless foodstuffs and increases meat avoidance intent, which translates into a higher probability to choose a vegetarian wrap rather than a meat-containing wrap. Two online studies illuminate the underlying psychological process, which is mediated by perceived self-similarity to human and non-human animals.Identifying individual traits that are associated with heightened enjoyment of meatless foods facilitates marketing segmentation for meatless foodstuffs. Furthermore, the tested compassion-inducing visual stimuli can be adapted for product packaging or employed in restaurant décor to elevate consumers’ subjective taste of meatless foods, potentially counteracting the negative individual and societal health effects of excessive meat intake.The moderating effect of meat avoidance intent on subjective taste suggests that, for people who consider reducing their meat intake, transitory zones exist where the perceived enhancement in taste of vegetarian food is not sufficiently motivating to change dietary practices permanently and it may appear more rewarding to simply revert to meat consumption. Social marketers can focus on these zones where moral conflict about meat consumption is salient by providing support to make dietary transitions less frustrating.This set of studies is the first to articulate the connection between compassion and ethical food choices in a consumer-relevant context. The findings point towards avenues to promote meat reduction, improve individual physical and mental health, and reduce the environmental impact of meat production.     

mini-MPN-STE-qPCR法快速定量检测食品中沙门氏菌

目的 建立一种快速、简易、可定量检测食源性沙门氏菌定量PCR(quantitative PCR, qPCR)方法。方法 依据沙门菌属invA基因序列设计染料法qPCR引物, 建立基于嵌合荧光法的沙门氏菌qPCR检测方法, 并通过短时间增菌(short time enrichment, STE)的5管微型多管发酵计数法（mini-most probable number, mini-MPN）进行定量检测, 构建mini-MPN-STE-qPCR法。使用人工污染的鸡肉混合液进行定量检测, 检测结果与传统MPN计数法和平板计数法进行比较分析。结果 建立的 qPCR法特异性良好, 方法灵敏度为50 CFU/mL, 结合48孔板min-MPN和4h 短时间增菌建立的mini-MPN-STE-qPCR法可将整个检测流程缩短至7 h。人工添加沙门氏菌的鸡肉混合液检测结果表明方法检出限为-0.347 log MPN/mL, Bland-Altman分析结果显示, 此法与传统MPN计数法相关系数R2=0.994, 与平板计数法相关系数R2=0.992。结论 该方法准确、简单易行、成本低、灵敏度高, 可用于食品中沙门菌的快速定量检测。     

双螺杆挤压过程中停留时间分布的测定及影响因素研究

停留时间分布是表征双螺杆挤压过程中物料流动状态的重要参数,与挤压食品品质的形成密切相关。文章着重介绍了指示剂测定停留时间分布的方法及相关参数,分析了温度、水分、螺杆构型、模孔、喂料速度和螺杆转速等操作参数对双螺杆挤压过程中停留时间分布的影响。由于淀粉、蛋白等营养组分结构比较复杂,现有关于停留时间分布的研究成果不够完善,还需要进一步的深入细化。     

Carbon dioxide as a novel indicator for bacterial growth in milk

Human milk spoils due to bacterial, yeast, or mold contamination. Current domestic methods of assessing milk spoilage are subjective or rely on time and temperature-based guidelines. A key unmet food safety need remains the objective assessment of human milk spoilage. Experiments were conducted using a simplified human milk spoilage model based on goat's milk as a human milk surrogate, spiked with a single bacterial strain (Staphylococcus epidermidis), in which pH and carbon dioxide (CO₂) concentration were measured along with bacteria count over 160 hr. Bacteria count correlated highly with CO₂ but not with pH. A 0.21% CO₂ concentration threshold could be defined for milk spoilage (correlating to a bacteria count threshold of 10⁵ CFU/ml), with sensitivity and specificity above 84%. These findings suggest that CO₂ measurement is a promising method to detect S. epidermidis growth in milk which merits further investigation for the objective and quantitative assessment of milk spoilage.     

PCR-核酸试纸条法检测食品中假结核耶尔森菌

目的 建立一种基于PCR-核酸试纸条技术快速检测食品中假结核耶尔森菌的方法。方法 将10株假结核耶尔森菌株和9株其他耶尔森氏菌及18株来源菌株作为实验菌株进行特异性实验; 通过纯菌液计数、干扰菌实验检测进行灵敏度验证。结果 DNA检测可达到10?3 μg/mL, 25 g样品加菌实验灵敏度可达 100 CFU/25 g, 添加10倍干扰菌不会降低检测灵敏度。利用建立方法对市场购买的食品进行筛查并与国标方法进行比较, 建立方法的灵敏度优于国标方法。结论 该方法检测结果准确, 灵敏度高, 适用于检测食品中假结核耶尔森菌。     

唾液流率与辣味强度分级的相关性分析及模型建立

本研究旨在通过测定受试者食用不同浓度的辣椒碱溶液后的唾液流速,探讨辣度与唾液流速的相关性,建立快速测定食品辣度的方法。以人食辣后引起唾液分泌增加的生理变化作为辣味强度的影响指标,通过受试人员的唾液分泌量计算不同辣味强度下的唾液流率,对辣味强度和唾液流率之间的关系进行拟合,基于拟合模型,构建快速、准确标定辣度的唾液流率分级体系,并用感官评定法验证模型定级结果。结果表明:辣味强度显著影响唾液流率（P<0.05）,可以通过唾液流率对辣度进行准确快速的分级。根据唾液流率范围,将辣度分成了5级:1级微辣[斯科维尔指数（SHU）10~500（含）]:唾液流率（g/min）0.496 ~1.395（含）;2级轻辣[SHU500~1000（含）]:唾液流率（g/min）1.395~2.153（含）;3级中辣[SHU1000~1500（含）]:唾液流率（g/min）2.153~2.749（含）;4级重辣[SHU1500~3000（含）]:唾液流率（g/min）2.749~3.569（含）;5级猛辣（SHU>3000）:唾液流率（g/min）>3.569。通过收集5~10人食辣后唾液分泌量,结合辣味强度与唾液流率之间的数量关系即可快速对测试者所尝食物辣度进行定级;唾液流率辣度定级结果与感官评定结果处于同一辣味量度等级,能反映出人食辣后的真实辣度感受。     

Accelerated ripening of cheese using liposome-encapsulated enzyme

Improved efficiency of liposome encapsulation of a cheese-ripening enzyme and increased retention of encapsulated enzyme by cheese curd are reported. The economy of enzyme usage for accelerating the rate of ripening of Cheddar cheese has been improved about 100-fold over previously reported methods. This has made feasible the use of microencapsulated enzymes for large-scale cheese production. Objective measurement of cheese ripening by proteolytic indices, and subjective evaluation of flavour quality and intensity by trained taste panels, indicate that cheeses are ripened by the microencapsulated enzyme in half the normal time. Investigations aimed at further improving the efficiency and commercial feasibility of the process are reported, and the possibility of using this technology for other aspects of food processing are discussed.