食品专业英语 LESSON 2 Carbohydrates.docxVIP

The food scientist has a many-sided interest in carbohydrates. He is conce rned with their amounts in various foods, availability (nutritional and economi c), methods of extraction and analysis, commercial forms and purity, nutritiona 1 valve, physiological effects, and functional properties in foods. Understand! ng their functional properties in processed foods requires not only knowledge o f the physical and chemical properties of isolated carbohydrates, but also know ledge of the reactions and interactions that occur in situs between carbohydrat es and other food constituents and the effects of these changes upon food quali ty and acceptance. This is a tall order for knowledge. Because processing affec ts both nutritional and esthetic values of food, knowledge of the changes that carbohydrates undergo during milling, cooking, dehydration, freezing, and stora ge is especially important. Students are advised to study the fundamental chemistry underlying u seful carbohydrates properties Of service will be an understanding of the assoc iation of polar molecules through hydrogen bonding, ionic effects, substituent effects, chelation with inorganic ions, complexing with lipids and proteins, an d decomposition reaction. This background will provide an understanding of prop erties that affect the texture and acceptance of processed foods (e.g., solubil ity, hygroscopicity, diffusion, osmosis, viscosity, plastity, and flavor produc tion), properties that enable the formation or high quality pastries, gels, coa tings, confections, and reconstitutable dehydrated and frozen foods. Ability to predict what changes in functional properties are likely to ensue from incorporating various types of carbohydrates into processed foods is a practical goal of the food scientist.Such forecasting requires either a weal th of experience with trial-and-error methods or a deep knowledge of carbohydra te properties as related to structure一perhaps both. However, scientific knowle dge of cause