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

Objectives laws, Objectives While undertaking this exercise and after i...

Objectives While undertaking this exercise and after its completion, you should be able to: share with your peer group, the relevant information1 knowledge/opinions with regard

Cloud made of comets, A Cloud Made of Comets The cold outer areas bey...

A Cloud Made of Comets The cold outer areas beyond Pluto are the regions of  comets, those visitors that dash, around the Sun, seldom to be seen again. Comets are of grei3t

#titlrespiratione.., what are the four characteristics of respiratory surfa...

what are the four characteristics of respiratory surface

Explain the porphyrins in the urine, Explain the Porphyrins in the urine ...

Explain the Porphyrins in the urine Porphyrins (a group of compounds containing the porphin structure, four pyrrole rings connected by methine bridges in a cyclic configuration

Periodic table, why does the periodic table useful to scientist

why does the periodic table useful to scientist

Biochemical evidence, Biochemical Evidence: As we had said earlier in...

Biochemical Evidence: As we had said earlier in section 13.2, Darwin had  recognized  that humans and the great apes shared many physical characteristics. This led him  to co

Social and economic impact of modern communication, Social and economic imp...

Social and economic impact of modern communication technology: Quite obviously a society which will utilise advanced communication technology in  the ways mentioned above, woul

Balloon experiment, Another balloon experiment Stretch a rubber balloon...

Another balloon experiment Stretch a rubber balloon over the neck of a little bottle. Place it in the receiver jar and delete some of the air with the pump. What happens? How d

Softening water with chemicals, Softening water with chemicals Try mak...

Softening water with chemicals Try making suds with a half test tube of hard water and a few drops of soap solution. Next boil a same sample and again try to make suds by usin

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

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