Explain the process of freezing, Science

Assignment Help:

Explain the process of Freezing

Freezing, as a method, is the easiest, most  convenient and least time-consuming way of preserving foods. Freezing does not sterilize foods or destroy the organisms that cause spoilage. How then does it preserve foods? Well, the  extreme cold simply slows the growth of microorganisms and the chemical changes that affect quality or cause spoilage. You already know that all microbial and biochemical activities are temperature dependant and slow down as the temperature is reduced. As a rule of thumb, for every 10°C temperature change, the rate of reaction changes by a factor of 2 to 3. 
 
Further, freezing helps to preserve food by its action on enzymes. Enzymes, as you already know are complex proteins, present in all living tissue, that help organisms ripen and mature. During freezing, enzyme action is slowed but not stopped. If not inactivated, these enzymes can cause color and flavor changes and loss of nutrients during freezer storage. 
 
We are all familiar with chilling and refrigerated storage. At home or at the industry level, refrigerated storage of food is generally practiced. In the unit operation of chilling, the temperature of a food is reduced generally to between -1°C and 7 °C and thus subsequent storage at refrigerated temperature extends the shelf life of both the fresh and processed foods. It is also used as an adjunct process to extend the storage life of mildly processed (e.g. pasteurized, fermented and irradiated) and low-acid foods. In the United States, refrigerated storage of food is mandated by regulations at temperatures at or below 7.2°C.  Such foods are also marketed under refrigeration and labeled as 'needing refrigeration'. Commercially sterilized and processed foods that may become contaminated after opening should also be labeled for refrigerated storage.
 
Chilling and refrigerated storage prevents the growth of bacteria, particularly the thermophiles (organisms that grow at high temperature) and mesophiles (organisms that grow at medium temperature). Psychrophiles (organisms that grow at low temperatures), however, can and do cause food spoilage during low temperatures  storage, but there are some psychrophillic pathogens.

611_freezing.png


Related Discussions:- Explain the process of freezing

Phase diagram for single component system, why don''t we have a crtical poi...

why don''t we have a crtical point on the solid liquid equilibrium line as we have on the liquid-vapour line...

Define the functions of platelets, Define the functions of platelets Th...

Define the functions of platelets The main function of platelets, or thrombocytes, is to stop the loss of blood from wounds, i.e. haemostasis. Let us learn about this function.

Explain active transport - mechanism of urine formation, Explain Active Tra...

Explain Active Transport - Mechanism of Urine Formation Active transport: When the substances are transported through a cell membrane against a concentration gradient, that is,

What a molecule difference between molecules and compounds, What a molecule...

What a molecule is, and the difference between molecules and compounds? A molecule is made up of two or more atoms combined chemically. The atoms can be of the same element, as

Explain the freezing systems, Freezing Systems Different types of free...

Freezing Systems Different types of freezing systems are available for foods. No single freezing system can satisfy all freezing needs, because of the wide variety of food pro

Eyes, information about the eyes

information about the eyes

Explain fortin type barometer, Fortin type barometer A simple Fortin ty...

Fortin type barometer A simple Fortin type barometer can be improvised for the junior laboratory. The glass tube is held vertically with single end in the reservoir by two curt

Rejection of heliocentrism, Rejection of Heliocentrism: This happened...

Rejection of Heliocentrism: This happened  in the year  1918 when the astronomer Harlow Shapley (1885-1972) first surveyed the size and shape of  the Milky Way Galaxy. He  sh

Show the steps needed to derive the recursive formula, Consider the followi...

Consider the following differential equation: t 2 x''+ 5 t x' + (3 + 2 t) x = 0 a. Show the steps needed to derive the recursive formula for the coefficients of the pow

Utilitarianism - philosophical medical ethics, There is something very attr...

There is something very attractive about the straightforward idea that morality is all about maximising happiness and minimising misery: that one's actions are right insofar as the

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd