Food Enzymes Flashcards
what are food enzymes
- catalysts that speed up a reaction without being altered
- they have an optimum temperature and pH
what are the food enzymes used in food processing
Isomerase catalyses the conversion of delta-glucose to delta- fructose, fructose is sweeter than glucose
Invertase catalyses sucrose and water to alpha-delta-glucose and beta-delta-glucose, they are more stable and are less likely to crystallise
Lipoxygenase catalyses unsaturated FAs into FA hydrperoxides, which cause fat rancidity which is undesirable, but are also used in bread as they improve dough and flavour
Proteases are used in meat tenderisation and cheese making and provide an umami taste (pleasant and savoury)
what is an example of a therapeutic food enzyme
lactase
- used for those who cannot digest lactose
give examples of where some chemical reactions that take place in food occur
Carboxyl Group
Amino Group
Thiol Group
Explain the chemical reactions that involve the carboxyl group
- Decarboxylation- removal of the carboxyl group- of histidine, converting it to histamine- this wants to be avoided as it can be the cause of allergic reactions
Explain the chemical reactions that involve the amino group
- Acetylation- adding an acetyl group- increases protein isolate solubility
- Nitrosamines- a carcinogenic compound containing the group =NNO attached to two organic groups is added- provide a desirable colour and flavour to meat products and reduce the rate of spoilage
- Maillard reaction- a chemical reaction between amino acids and reducing sugars- gives browned food its distinctive flavour
Explain the chemical reactions that involve the thiol group
- disulfide bonds increase elasticity of dough and create a more desirable meat texture
- although it does cause decolorisation in low acid and high protein conditions (such as canned meat), and oxidation during freezing can lead to rancidity
