6. Commercial food uses of processed fats and oils
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
卡片预览 (19 张)
what are the 5 commercial food uses of processed fats and oils?
• shortenings (baking and snack food production) • confectionery and specialty fats • frying oils and shortenings • ingredients in emulsions: margarines, mayonnaises, salad dressings • ingredients in many other processed foods
Why are fats (shortenings) incorporated into baked products?
to reduce interaction of wheat proteins (separate protein from each other) to produce desirable “shortened” or crumbly texture for cakes, pie crusts, cookies
4 important characteristics of shortenings? –> physical characteristics depend on what? (2)
air, plasticity, consistency and solid-liquid ratio - depend on polymorphic forms of the fats! + methods of preparation
Shortenings: beta prime and beta crystals: small or large amount of small or large air bubbles? gives what characteristics?
• beta prime: large amount of small bubbles = whiter, creamier, more tender, smoother texture + uniform and glossy texture • beta: small amount of large bubbles = waxy or grainy texture
shortenings: why does randomization of lard through interesterification improves its plastic range?
• natural lard –> palmitic acid: at 2 position = 64% –> beta crystal (OPS) • rearranged lard (palmitic acid: at 2 position = 24% –> beta prime crystal (POS)
consistency vs plasticity?
• consistency: apparent hardness at a given temperature • plasticity: changes in consistency as a function of temperature
what is required to form mixed crystals required for a broad melting range? - what can melting range induce/change?
• tempering! • plasticity, consistency and solid-liquid ratio depend on melting range
What is tempering?
process which permits transformation to proper polymorphic form
melting range of confectionery fats depends on (3)
• FA composition • location of FA in TG • proper crystallization
does cocoa butter have a short or big melting range? + 80% of cocoa butter is ______________ TG
• short! at mouth temperature • disaturated –> stearic x 2 OR stearic + palmitic OR palmitic x 2 (the 3rd FA is oleic)
how does randomizing hydrogenated palm kernel oil changes its melting point?
• reduces melting point from 46°C to 35° • not waxy feeling in mouth anymore
what are frying oils and frying shortenings used as?
heat transfer agents! –> frying allows high temps to be reached, driving out water from product and allowing browning and flavor development reactions to take place
commercial frying/fast food restaurants –> what were their heat transfer medium of choice in 2018 vs now?
2018: partially hydrogenated vegetable oils - today: high oleic-oils obtained by plant breeding or genetic modification
3 characteristics of high-oleic oils used as frying oil
• can withstand high temps • provide relatively long fry life • resistant to producing off flavors bc of thermal deterioration and oxidative processes
what are emulsions?
intimate mixtures of water and oil that normally break/separate
role of emulsifiers? how?
• stabilize and reduce interfacial tension between hydrophilic and hydrophobic constituents • by having hydrophilic and hydrophobic groups
2 good emulsifier examples?
• monoglycerides • phospholipids
once an emulsion is formed and stabilized, how to the properties of lipid system change?
• more viscous and opaque • fatty sensation is masked
Roles of lipids in diet (6)
• concentrated form of calories • integral constituent of cell membranes • supply essential FA (linoleic and linolenic) • provide means of contributing fat soluble vitamins • serve lubrican function • contribute to feeling of satiety or fullness