第九章 食品蛋白质的功能性质

4. Water binding - where the protein binds water to give a softer texture to the product
• • • • meat proteins in sausages egg proteins in surimi wheat proteins in cakes but water may shift (migrate) to other components in the product • this shift occurs over time --> staling, texture changes
三、功能性质的影响因素
ÄÄÄ ò Ä Ä °° ³Ä³ é Ä Ä °° ³ÄÄ µ Ä ÄÄÄ ò Äij é ² Ä
Ä ²ÄÄ ò Ä PH ÄÄÄij ÄÄ ÄÄÄÄ ´ ÄÄ ¨Ä IJ Ä ÄÄÄÄÄ ÄÄ ´ ÄÄ ± í ÄÄÄÄ ² ÄÄÄÄ
ÄÄ ¤ÄÄ í ÄÄÄÄÄ Ä ÷ÄÄ µ ÄÄ Ä³ ÄÄÄ ÄÄÄÄÄ Ä ü ÄÄÄ Ä °° ³ÄÄÄ
à ù ¼ ¹ ß ¸ Ð Ö Í µ Ð Ö Ð Ö Ð Ö
ห้องสมุดไป่ตู้
à ¤Ï Í ³ È Ð Ö Í µ ß ¸ Ð Ö ß ¸ Í µ
Ô ¶ È Ô ¶ È ÈÎ È Ë á Î È È¢ ¡ È» ²
Í Ç ¶ ¨Ï Ô » ² ΠȨ ¶ » ² ΠȨ ¶ ¨ ¶ £ ¬Ë á » ² ΠȨ ¶ ¨ ¶ £ ¬È » ² ΠȨ ¶ Ë á » ² ΠȨ ¶ ΠȨ ¶
二、功能性质分类
¿ ´ ± ð · Ï ¸ Ù Ï Ô Ö É Ö ª ½ õ Ï Ô Ö É Ê ® º ¯ Ï Ô Ö É ± í  æ Ï Ô Ö É ¼ µ ¸ Ó è À ÷ ± ä Ï Ô Ö É Å ä Ê ø  ¶ É ö È « Ö É Ç ó ³ í Ç · Õ ³ ½ Û Ó è Ô ó ¸ É ª ¶ Ç º ¯ ¶ Ç » ¯ Å ä £ ¬ £ ¬ £ ¬ £ ¬ £ ¬ £ ¬ £ ¬ Ê ø Å ÷ ¾ Ú Í ü à ù Å ð µ ¯ à ù ³ È Í ¶ £ ¬ · Ï £ ¬ Ê ® ¡ ¢ ¶ ³ £ ¬ Ä Ý £ ¬ Ï Ô £ ¬ ¼ ¹ £ ¬ ² Ö µ à ³ Ë Í ¶ ¾ Ä À £ · Ï £ ¬ º è ³ Æ · Ï £ ¬ ½ ³¼ ¿ · Ï ³ Ö Ê ® Ï Ô £ ¬ Ç Ü Õ Ì £ ¬ Ç Ü ¼ â ¶ Ç £ ¬ Ì Ð Ê ® É Õ Ê õ µ °° ³-Ö ¬ Ö É Ã ¤Ï Í ³ È £ ¬ Ö ¬ Ö É ¼ µ ¹ Î £ ¬ ² ç Í ¶ ¼ µ ¹ Î Õ ³ ³ Ä À ¦ £ ¬ Ã Ú ½ Û À ¦ £ ¬ Õ ³ ³ í Ï Ô £ ¬  æ Ì Ä Ï Í ³ È £ ¬ Ì ÷ Á ç Ï Í ³ È £ ¬ » ²Ð ¸ ³ È Ï Ì Ï Ô £ ¬ Î Ê Í ¬ Ï Í ³ È Î ´ Ç Ý Ï Ô £ ¬  · º é Ï Ô £ ¬ ¾ ¸ Ð õ º ¯ Ï Ô
• many soy beverage will have a sediment • the soy milks use various emulsifiers and dispersants
2. Viscosity - where the protein gives a thick/viscous characteristic to a food
6. Elasticity - where proteins give a stretch or bouncy character to a food
• egg white in angel food cakes • meat proteins in wieners (a very complex structure)
– 12 of the more common functionalities 1. Solubility - for use in protein beverages
• our main protein beverage is milk from cows • the protein concentration is ~3.5% • BUT this is not a true protein solution because the milk is dispersed as a colloidal particle • egg and whey proteins will stay in solution at the 4% level (may need some acid and sugar to assist solubility) • soy protein is usually difficult to solubilize
9. Fat binding - the physical holding of fat (i.e. not emulsified)
• egg protein holding fat in doughnuts • wheat gluten holding fat in baked products
7. Emulsification - where the R groups on a protein interact with lipid and aqueous components in a food
• egg and milk proteins in salad dressings
8. Foaming - where a protein can trap air within a 3-D network of protein film and fibers
5. Cohesion/adhesion - where proteins act as a ‘food glue’
• high levels of egg white in surimi can give it a rubber ball-like texture, a strong cohesive property • whey proteins also have this glue-like characteristic • will have a major influence on chewing properties
12. Sensory - proteins can contribute to the colour, taste and smell of a food product
• egg white is light yellow in colour • wheat gluten has a very grain-like flavour • whey protein may have a dairy type of smell
蛋白质来源是影响功能性质的重要因素
¿ ´ Ô ´ ° µ å Ç ° µ Æ » Ò À° µ ° × È é å Ç° µ ° × ó ´ ¹ ¶ ° µ ° × ã Ó° µ ° ×
Ç · º ¯ Í µ ß ¸ ß ¸ Ð Ö ß ¸ Ð Ö
Å ð Ä Ý ß ¸ Í µ Ð Ö Ð Ö Í µ Í µ
– Functions of proteins in foods
• how proteins contribute to the characteristics or properties of a food product • the physiochemical properties of proteins in a food • protein functionality
10. Film forming - where protein films or sheets are formed
• especially in baked goods by wheat gluten and egg proteins • gives structure to a product and helps to prevent the migration of water
11. Fiber forming - to simulate meat texture
• especially egg and soy proteins • fibers or fiber-like characteristics are formed by extrusion or spinning equipment
第九章 食品蛋白质的功能性质
1. 2. 3. 4. 5. 蛋白质功能性质基本概念 水化性质 凝胶性质 表面与界面性质 蛋白质-多糖相互作用
第一节 功能性质的概念
一、蛋白质功能性质的定义
所有影响蛋白质在食品中的功能的性质营养性质除外。 决定了蛋白质在食品的加工、贮藏、配制及消费过程中行为的物理化学性质。 蛋白质的功能性质影响食品的物理化学性质、加工性能、产品质量，不同的 食品要求不同的功能性质 大豆蛋白开发促进了功能性质研究
• • • • whipped casein toppings, cold stable whipped egg nougats in malted milk bars, RT stable whipped egg meringues and nougats, heat set foamed milk proteins in ice cream, cold set
各种蛋白质在不同食品中的作用方式不相同
¹¹¹¹ ÷¹¹¹ × ¹¹¹ °° ¹ ×¹¹¹ ü¹¹¹ ¹ á¹¹ ¹¹ ü¹¹× ¹¹ ü¹ á¹¹ ¹¹ ¹¹ í¹¹ á¹ ¹ ¹¹ ¹¹ á/¹× ¹ ¹¹ ¹¹ é ü¹¹ ¹ ¹¹¹ · á¹ ¹¹ ¹¹¹¹¹¹ °° ¹ ×¹× ÷¹¹¹¹¹ ¹¹ °° ×¹ ¹¹ è¹¹ ü¹¹ ¹¹¹¹¹ ò¹ ü ¹¹¹¹¹ ¨¹ · ¹¹ é× ¹¹ á¹¹¹¹· ¹ ¹ ¹¹¹¹ ¹ · ü¹¹¹× ¹¹ ¹· ¹ ¹¹¹ °° ×¹ ¹ ¤¹× ¹¹ ¹ ¹¹¹¹ ó ¹¹ ¹¹¹ ·¹¹° ü¹¹ °¹ ¹¹¹¹¹¹ ¹¹¹ ·¹¹¹ é¹¹¹¹ ¹¹ ¹¹¹ ·¹± ¹¹¹¹ ·¹¹ ¹¹¹¹ ¹¹¹ ·¹± ¹¹¹¹ · ¹¹¹ ·¹¹¹¹¹ ¹¹¹ ·¹¹¹ ¨¹¹¹ · ¹¹¹¹ · ·¹± ¹¹¹¹ · ¹¹¹¹¹¹¹¹¹ °¹
• gelatin in yogurts • use level is usually 1 to 3% gelatin, depending on the desired firmness of the product • some soy proteins have been chemically modified (partially denatured) to give a type of viscous property
3. Gelation - where a firm gel is established
• gelatin at 4-6% in desserts to give a characteristic texture • casein in cheese (~ 35% level) • some modified soy protein, synthetic cheeses
– whole books have been written on these individual functionalities – many patents describe these properties (give ownership for 20 years and then the information is in the public domain)