Correct Answer - Option 4 : 79.4
Most food and microbial enzymes are destroyed at 79.4°C. Higher the optimal and maximal temperature for growth, the greater the resistance to killing.
Enzymes are complex chemical substances, which are present in all living organisms and tissues, which control essential metabolic processes. They speed up chemical changes that result in loss of flavor, color, and texture.
- Enzymes are heat sensitive because majorly enzymes are composed of protein.
- Enzymatic spoilage is the greatest cause of food deterioration. They are responsible for certain undesirable or desirable changes in fruits, vegetables, and other foods. Examples involving endogenous enzymes include:
- In guava, deteriorative enzymes such as peroxidase (POD), polyphenol oxidase (PPO), pectin methylesterase (PME), and ascorbate oxidase (AO) lead up to the loss of quality of guava fruit and its products.
- These endogenous enzymes may adversely affect sensory and nutritional attributes if not inactivated during processing.
- Some enzymes such as proteases and lipases may withstand higher temperatures, especially if high temperature for a short duration is employed. This is called pasteurization.
- These enzymes retain a level of activity after an ultrahigh-temperature (UHT) process(over 136 °C).
- The residual activity of the enzymes may spoil the processed product during long-term storage.
- The most effective used method for destroying microorganisms and inactivating enzymes is heat treatment.
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Microbial enzymes are known to be superior enzymes obtained from different microorganisms, particularly for applications in industries on commercial scales.
- Four enzymes are now produced on a large scale: protease, glucoamylase, alpha-amylase, and glucose isomerase.
- Microbial enzymes find applications in many fields, including chemical, fermentation, agricultural, pharmaceuticals, and food production.
- Bovine phosphatase, if present, in processed milk indicates that the milk was not properly pasteurized.
