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

Food web, Food Web: Within an ecosystem,  there are many different food...

Food Web: Within an ecosystem,  there are many different food chains. Some organisms may be involved in several of the food chains at the same time. So a number of food chains

Explain the regulation of thyroid hormone secretion, Explain the Regulation...

Explain the Regulation of Thyroid Hormone Secretion TSH from the anterior pituitary gland controls the secretion of thyroid hormones. Thyrotropin Releasing Factor (TRF) from th

How does the atmosphere act as a blanket, Q.How does the atmosphere act as ...

Q.How does the atmosphere act as a blanket? The atmosphere acts as a blanket by performing the following functions: (a) It keeps the average temperature of the Earth fairly c

Landforms, is a grassland a type of landform

is a grassland a type of landform

What is the earth crust made of, What is the earth crust made of? Ans) ...

What is the earth crust made of? Ans) The overall composition of the Earth crust is as follows: Silicon 27.7% Oxygen 46.6% Iron 5.0% Aluminum 8.1% All other elem

Hazards in the laboratory, HAZARDS IN THE LABORATORY : Laboratories in...

HAZARDS IN THE LABORATORY : Laboratories in the biology department of schools, colleges and universities and other higher level organisation such as hospitals, veterinary esta

Discuss the important gastro intestinal procedures, Question 1 Explain ...

Question 1 Explain the following disorders a) Thalassemia b) Hemophilia c) Tetralogy of Fallot d) Ac

Define eicosanoids, Eicosanoids : Local hormone formed by  body  tissues...

Eicosanoids : Local hormone formed by  body  tissues during self-healing responses to stimuli.

Define the pre motor areas of the cerebrum, Define the Pre Motor Areas of t...

Define the Pre Motor Areas of the Cerebrum The pre motor areas too lie in the frontal lobe immediately anterior to the motor area as highlighted in the Figure. The cells are th

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