CONTROL OF A FOOD PROCESS BASED ON SENSORY EVALUATIONS

Sensory evaluation is often the ultimate measure of food quality, but food process control relies on instrumental measurements. In this research, a strategy for using sensory evaluations in food process control was explored on the basis of a rice cake production process. Important sensory attributes were first modeled as functions of instrumental variables (manipulated or instrumentally measurable variables) to determine the potential controllability of the sensory variables. Neural networks were used to convert sensory quality targets into process control set points. Trained neural networks effectively predicted the instrumental measurements or process set points that resulted in certain sensory qualities. The neural networks were used to determine the best process set points for a given set of sensory targets, and the set point values were used to produce new product samples. The sensory attributes of the new rice cakes were close to those defined as the targets. The results demonstrated the effectiveness and potential of the method.     

DEVELOPMENT OF A SENSORY TEXTURE PROFILE OF COOKED POTATOES BY MULTIVARIATE DATA ANALYSIS

A sensory texture profile of cooked potatoes ( Solanum tuberosum ) was developed through two training periods in 1995 and 1997. Training time necessary to obtain a reliable sensory panel in assessing texture attributes was studied by the use of univariate and multivariate data analysis. The panel was interviewed and introduced to the Texture Profile Method. A list of texture attributes, ranging from non oral terms to terms evaluated after the first bite and the following mastications, was developed resulting in 14 texture attributes, Analysis of variance (ANOVA), discriminant partial least squares regression (DPLSR) and principal component analysis (PCA) was used to reduce the texture profile to 8 reliable sensory attributes covering the geometrical (reflection, mealiness, graininess), mechanical (firmness, hardness, springiness chewiness) and moistness characteristics. These variables explained 89% and 86% of the total variance in 1995 and 1997, respectively. Relevant criteria for studying panel performance are discussed. Training for more than one day did not significantly improve panel performance. Geometrical attributes as well as moistness were found easier to evaluate than the mechanical attributes.     

Optimization of Extrusion Cooking Process for Chickpea (Cicer arietinum, L.) Defatted Flour by Response Surface Methodology

Response surface methodology was employed to optimize the production of a snack food from chickpea. The independent variables, process temperature (123–137°C) and feed moisture (13–27% d.s.b.) were selected at five levels (rotatable five level composite design: ?√2, ?1, 0, 1, +√2) in the extrusion of defatted chickpea flour. Response variables were expansion ratio, shear strength of the extra-date and sensory preference assessed by an untrained panel. Expansion ratio increased steadily with decrease in feed moisture similar to cereal extrusion. Regions of maxima were observed for sensory preference and shear strength, and these two product attributes were linearly related. The most acceptable chickpea snack was rated higher than a commercial corn snack.     

Identification of Key Textural Attributes of Fluid and Semi-Solid Foods Using Regression Analysis

Regression analysis was used to identify key attributes from 15 textural terms generated by a panel for 27 fluid and semi-solid commercial foods. A search using single independent variables showed that “thick” gave the best average R² with a value of 0.548; a search with two independent variables showed that “thick” and “soft” gave the best average R² of 0.748; a search with three attributes showed that “slippery”, “thick,” and “soft” gave the highest R² values of 0.803. The final equations provided a set of regression parameters which can be used to predict twelve textural attributes from scores obtained for “thick”, “soft”, and “slippery”.     

Texture Assessment of French Cheeses

The texture of a variety of French cheeses was studied by examining their compositional and mechanical parameters. The data obtained were correlated to those derived from a panel assessment of the sensory textural attributes of the samples. Statistical treatment of the results employing cluster analysis, analysis of variance, and redundancy analysis revealed that the most influential objective variables to characterize the cheese texture are the dry matter content and the resistance to force compression at 10% deformation of the initial sample height. These variables were highly correlated with sensory attributes such as hardness, brittleness, cohesiveness, and adhesiveness.     

Food security in a remittance based economy

We interviewed 395 subsistence farming households from Chitwan, Nepal in order to identify the impact of remittances and other explanatory variables on child, adult, and household food security. The highest category of the IV - ordered probit regression models with cluster robust standard errors indicated that the food security status of households, adults and children was explained by gender and age of household head, adoption of conservation agricultural technology, number of fruit trees, and income from agricultural and livestock sources. Additional variables affecting only children’s food security were the adoption of hybrid rice or maize varieties and the wage income or salary earned within the district, whereas an additional variable affecting only household and adult food security was the wage income earned outside the district. Households receiving international remittances were more food secure than those households that did not receive such remittances.     

An analytical and integrative approach to sensory evaluation of foods

Total sensory evaluation of foods involves at least four senses each of which may include one to many distinct attributes of quality. Thus it is necessary to test for the various significant attributes separately before arriving at a total quality assessment. Sensory evaluation may be performed directly by the use of the “human instrument”, i.e. taste panel, or indirectly by the use of objective physical-chemical tests which must be validated by demonstrated high correlation with taste panel responses. For determining differences, panelists should be trained. For consumer preference, untrained panels representative of the target population must be employed. In either case, scalar, variables, rather than attributes data should be utilised for maximum efficiency (power). The sample number ratio (s.n.r.) is presented as a technique for measuring the relative efficiency of taste-testing procedures. The contribution of specific attributes to total sensory quality may be calculated by the use of multiple regression analysis where total quality is the dependent variable and the specific attributes of quality are the independent variables. The independent variables contributing significantly to predictability of total quality are retained in the equation and the others are dropped. An example of this procedure, using subjective and objective procedures is presented.     

生鲜食品保鲜技术研究进展

随着人们生活水平的提高,消费需求和方式的转变,生鲜食品已成为城乡居民生活中的必需品,且需求量增长迅速。然而由于保鲜技术的相对滞后,生鲜食品产后腐败损失严重,成为制约我国农产品加工业和食品工业发展的重要因素之一。生鲜食品保鲜已成为当今农业、食品企业、物流业和消费者所关心的热点问题。本文以生鲜水产品和果蔬为主要对象,根据其品质特性和腐败变质机理,介绍生鲜食品保鲜技术的国内外研究现状及发展趋势,旨在为该技术的研究与应用提供一定的参考,推动生鲜食品产业的发展。     

Chemical, physical and sensory attributes for the characterization of an Italian dry-cured sausage

This work was designed to characterize Felino salami, an Italian dry-cured sausage. For this purpose, a wide range of chemical, physical and sensory parameters were studied in 29 samples. Seven chemical and physical variables were selected by using principal components analysis: namely, pH, NaCl/moisture, moisture/protein, soluble N/protein, lactic acid, elasticity index and sample luminosity (L(?)). The first two principal components were significant according to double-cross validation and accounted for 79% of variance. The seven-variable chemometric model shows that variability in the first principal component is determined by variables expressing the acidity and the extent of lactic fermentation, while the second component is determined by variables expressing the degree of ripening and is related to the sensory scores maturation and hardness, and to salami age (p < 0.001). Sensory scores were evaluated by a multivariate method to verify the consonance among assessors as to the different attributes. The semi-trained panel was consonant and reliable for five of the nine sensory attributes evaluated. The predictive ability of the chemometric model for the sensory attributes was assessed with cross-validation.     

Influence of sensory characteristics on the acceptability of dry-cured ham

The influence of different sensory attributes on the acceptability of dry-cured Iberian ham was studied. Partial least squares regression analysis showed that juiciness and several flavour traits were the major attributes positively influencing acceptability of dry-cured Iberian ham, whereas yellowness of the fat, dryness and fibrousness showed a negative influence. Using stepwise multivariate regression, juiciness and flavour intensity were the two traits that better explained the acceptability of dry-cured ham, the linear model obtained showing a regression coefficient of 0.526. The regression coefficient of acceptability with juiciness and flavour intensity was higher using a piecewise linear regression model (R²=0.759) showing, therefore, a discontinuous relationship between these variables. However, results on product acceptability have been obtained using trained panellists and it might be possible that the use of a consumer panel would change these conclusions.     

淀粉类凝胶三维打印研究进展

食品三维打印技术是食品加工业革命性的创新发展, 能够在未来解决我国食品加工业和食品产业面临的营养个人订制性以及生产适合老人和婴幼儿的易咀嚼食品诸多问题。淀粉是食品中最常见的组分, 其在高温发生糊化并且与其他组分交联形成的凝胶体系是很好的食品三维打印材料。本文先是阐释了挤压式食品三维打印技术的工作原理, 以及淀粉的结构及物理化学性质, 揭示了淀粉的物理化学性质与淀粉类材料三维打印形状稳定性之间的联系, 从而进一步介绍了材料特性、三维打印挤出行为及后处理方法对淀粉三维打印产品形状稳定性的影响以及兼具易咀嚼特性和个性化营养特性的三维打印产品的相关研究。     

基于品评小组可靠性筛选葡萄酒的香气描述符

利用定量描述性分析（0～5标度法）评价9 款国产‘赤霞珠’干红葡萄酒的香气特性,结合方差分析和多元统计分析方法,评估品评小组可靠性和规范葡萄酒香气特性感官描述符的筛选方法。结果表明,利用平均重现性指数Ri、检验统计量F值、均方误差（mean-square error,MSE）值和Manhattan图等能够有效评估品评员的重现性、辨别能力、可重复性以及品评小组的一致性。以可靠品评小组的感官数据为原始变量,通过几何平均值（M值）计算和排序,结合主成分分析（principal component analysis,PCA）和聚类分析（cluster analysis,CA）,规范了葡萄酒特征香气描述符的科学筛选方法,明确了实验‘赤霞珠’干红葡萄酒的香气特征：以黑醋栗、红醋栗等果香为主,有突出的焦糖、烟熏等焙烤类香气,兼有胡椒等佐料香气。     

Development of a total quality scoring system based on consumer preference weightings and sensory profiles: application to fruit dates (Tamr)

A scoring system for evaluating the total quality of a food product (Tamr) based on consumer preferences was developed and tested for validity. The development process started with a survey among adult date consumers in the United Arab Emirates to identify their perception of characterizing total quality of date fruit among specified attributes. The consumer subjective ranking of eleven specified attributes was used to derive a quantitative weighted factor for each attribute. Based on the weighted factor a quantitative scoring guide was developed. A panel evaluation of five date varieties (Khlas, Barhee, Boumaan, Fard and Ruzeiz) was conducted as an application of the developed scoring system. Panel evaluation results and consumer ranking and preference data of the same varieties compared well. In both panel evaluation and consumer ranking, Khlas variety was perceived to have the best quality by far among the tested varieties. Barhee and Boumaan varieties showed no significant variation between them in both panel evaluation and consumer ranking, and both were in the second order of preference. Variety Ruzeiz was in the lowest order of preference in both panel evaluation and consumer ranking. Testing of the method indicated its appropriateness in predicting total quality of a food product as would be perceived by consumers.     

Use of generalized Procrustes analysis (GPA) to test the effects of sex and carcass weight on sensory quality evaluations of Terrincho lamb meat

Generalized Procrustes analysis (GPA) was used to test the sensory attributes of Terrincho lamb meat, a product with Protected Designation of Origin (PDO) labelling. Effects of sex and carcass weight on the following sensory attributes: toughness, juiciness, flavour intensity, odour intensity, stringiness, and level of sweetness were tested. Tests were performed on 28 females and 29 males placed within three classes of carcass weight, 3 to 9 kg. Meat sensory quality was evaluated, within five sessions, by a trained taste panel. Meat was cooked in a conventional oven, cut into pieces, and delivered to the panel for evaluation. Data were analyzed using a GPA to minimize differences between assessors. Two factors explained 72.76% of the total variability. The panel did not clearly detect sex effects, yet could differentiate meat by carcass weight as heavier animals were toughest and had more intense odour and flavour, whilst light animals were most succulent.     

自选特性排序剖面法在食品研究与开发中的应用及研究现状

自选特性排序剖面法（Flash Profile,FP）是一种能够应用于食品工业的快速感官描述性分析方法。该方法是指通过描述一组产品的感官属性,并根据这些属性的强弱程度进行排序,从而获得产品间的相对差异。本文主要介绍了自选特性排序剖面法的发展脉络、实验流程、数据处理及数据分析等,结合该方法在食品工业中的应用,分析该方法适用的产品类型以及与其他方法相比较的优缺点,并对该方法的发展前景做出展望,以期为食品加工企业和相关领域的研究人员提供借鉴。     

Sensory attribute preservation in extra virgin olive oil with addition of oregano essential oil as natural antioxidant

Four commercial varieties of oregano are farmed in Argentina: "Compacto,"Cordobes,"Criollo," y "Mendocino." Oregano essential oil is known for antioxidant properties. The objective of this study was to evaluate changes in the intensities of positive and negative attributes in extra virgin olive oil with addition of essential oil obtained from the 4 Argentinean oregano types. Oregano essential oil was added into olive oil at 0.05% w/w. The samples were stored in darkness and light exposure during 126 d at room temperature. The intensity ratings of fruity, pungency, bitterness, oregano flavor, and rancid flavor were evaluated every 21 d by a trained sensory panel. In general, samples with addition of oregano essential oil in olive oil exhibited higher and lower intensity ratings of positive and negative attributes, respectively, during storage compared with the control samples. The first 2 principal components explained 72.3% of the variability in the olive oil samples. In general, positive attributes of olive oil were highly associated with the addition of oregano essential oil in darkness, whereas rancid flavor was negatively associated with them. Olive oil with oregano "Cordobes" essential oil was oppositely associated with light exposure treatments and negative attribute (rancid flavor) suggesting better performance as natural antioxidant of this essential oil in olive oil. The result of this study showed that the presence of oregano essential oil, specially "Cordobes" type, preserve sensory quality of extra virgin olive oil prolonging the shelf life of this product. Practical Application: Extra virgin olive oil is highly appreciated for its health benefits, taste, and aroma. These properties are an important aspect in this product quality and need to be preserved. The addition of natural additives instead of synthetic ones covers the present trend in food technology. This research showed that the addition of oregano essential oil preserved the intensity ratings of positive attributes in extra virgin olive oil during storage. The essential oil of the oregano variety called "Cordobes" exhibited better protecting effect on sensory properties of olive oil than the other oregano varieties. The addition of oregano essential oil should be considered for the food industry as a natural source of antioxidant additives for preserving sensory properties in extra virgin olive oil and other similar food products.     

Improving food safety within the dairy chain: an application of conjoint analysis

This study determined the relative importance of attributes of food safety improvement in the production chain of fluid pasteurized milk. The chain was divided into 4 blocks: "feed" (compound feed production and its transport), "farm" (dairy farm), "dairy processing" (transport and processing of raw milk, delivery of pasteurized milk), and "consumer" (retailer/catering establishment and pasteurized milk consumption). The concept of food safety improvement focused on 2 main groups of hazards: chemical (antibiotics and dioxin) and microbiological (Salmonella, Escherichia coli, Mycobacterium paratuberculosis, and Staphylococcus aureus). Adaptive conjoint analysis was used to investigate food safety experts' perceptions of the attributes' importance. Preference data from individual experts (n = 24) on 101 attributes along the chain were collected in a computer-interactive mode. Experts perceived the attributes from the "feed" and "farm" blocks as being more vital for controlling the chemical hazards; whereas the attributes from the "farm" and "dairy processing" were considered more vital for controlling the microbiological hazards. For the chemical hazards, "identification of treated cows" and "quality assurance system of compound feed manufacturers" were considered the most important attributes. For the microbiological hazards, these were "manure supply source" and "action in salmonellosis and M. paratuberculosis cases". The rather high importance of attributes relating to quality assurance and traceability systems of the chain participants indicates that participants look for food safety assurance from the preceding participants. This information has substantial decision-making implications for private businesses along the chain and for the government regarding the food safety improvement of fluid pasteurized milk.