Food textureand viscosity conceptand measurement AV food scienceand technology international series food scienceand technology là tài liệu bằng tiếng anh chuyên ngành công nghệ thực phẩm, bài giảng vật lí thực phẩm, các tính chất vật lí của thực phẩm và đi kèm là giới thiệu cấu tạo và cách hoạt đông của các loại máy sử dụng trong công nghệ thực phẩm
[...]... among the characteristics of appearance, flavor and texture according to the attributes’ 4 Texture, Viscosity, and Food importance to the respondent for 94 foods when eaten The overall means were 2.57 for appearance, 4.92 for flavor and 2.51 for texture which implies that texture is less important than flavor in food acceptability However, if we assume that the flavor score is equally divided between taste... of textures and flavors in their food as were the children of Israel many centuries ago A large part of the effort of the food industry of our day is directed toward providing both high quality and a wide variety of textures and viscosities in the foods that are provided to the public Status of Food Texture Measurements Of the three main acceptability factors of foods (appearance, flavor, texture), texture... Versus Viscosity Viscosity is defined as the internal friction of a fluid or its tendency to resist flow Both gases and liquids have viscosity but viscosity of gases will not be discussed because there are no gaseous foods However, some foods contain entrained gases For example, ice cream is typically 50% air by volume, and apple flesh may contain 25% gas by volume Some highly extruded crispy snack foods... that the food has poor flavor, whereas the consumer might have been referring to poor texture, or to both 4 An off-texture does not signal that the food is unsafe to eat, in contrast to odor, color, and flavor In extreme cases where putrefaction of protein-based foods leads to the liquification of the originally solid texture, it is the unpleasant odor that is the first indication of the food being... cradle to the grave CHAPTER 1 2 Texture, Viscosity, and Food Importance of Texture The importance of texture in the overall acceptability of foods varies widely, depending upon the type of food We could arbitrarily break it into three groups: 1 Critical: Foods in which texture is the dominant quality characteristic; for example, meat, potato chips, cornflakes and celery 2 Important: Foods in which texture... (English and Finnish) having very different linguistic roots’ Oram (1998) studied the food vocabulary of Australian schoolchildren aged 6–11 years, and adults, using 126 words that might relate to food, 10 non -food words (e.g jump) and 10 non-words (e.g frunp) He found that by age 6–7 (grade 1 in school) children already have a limited vocabulary that refers to a wide range of food attributes and this... describes the principles of objective methods of texture measurement, including ideas that have yet to evolve into commercial available instruments, and provides a foundation for the following chapter xvi Preface A major goal of this chapter is to move the thinking about texture from a foodby -food basis to general principles that can be applied to all foods Chapter 5 describes commercial instruments and... the overlooked quality attribute of foods This was reflected in the low proportion of foods whose texture was routinely measured, and the level of satisfaction with those tests that were used For example, Muller (1969b) reported a survey of food quality measurements made by the food processing industry in the United Kingdom A total of 125 companies reported on 228 food products with the following results:... that arise from eating their food From the nutritional standpoint it is possible to have a completely adequate diet in the form of fluid foods that require no mastication, Importance of Texture 3 Table 1.1 Percentage of Correct Identification of Pureed Foodsa Food Apple Strawberry Fish Lemon Carrot Banana Beef Rice Potato Green pepper Pork Cucumber Lamb Cabbage Mean for 29 foods Normal weight (young)... Institute of Food Technologists 16 Texture, Viscosity, and Food Figure 1.1 Comparison of physical measurement and human perception of light and texture (After Muller, 1969a.) LIGHT TEXTURE OPTICS (physical) VISION (perceived) RHEOLOGY (physical) HAPTAESTHESIS (perceived) reflection refraction wave theory size color shape light and dark adaptation Young's modulus shear modulus Poisson's ratio viscosity