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

Driving a boat by surface tension, Driving a boat by surface tension Se...

Driving a boat by surface tension Secure some gum camphor at the drug shop. Cut two or three boats from stiff paper, every about 2.5 cm in length. Cut a notch in the stern larg

A famous downslope wind that occurs in north america, A famous downslope wi...

A famous downslope wind that occurs in North America on the East side of the Rocky Mountains is called a: chinook

Pluto, Pluto: Pluto's  existence was also proposed  to account for de...

Pluto: Pluto's  existence was also proposed  to account for deviations in the orbit of Uranus. Even after the influence of Neptune~had  been accounted for, an American astron

Define nucleic acids, Nucleic acids are polymers  of  nucleotides. Nucleot...

Nucleic acids are polymers  of  nucleotides. Nucleotides  are nucleoside phosphates.

Moods - minnesota multiphasic personality inventory, Mr. X is probably well...

Mr. X is probably well adjusted (Mt=42). Neither he nor others see him as anxious (Pt=59), and he either denies or does not experience depressiveness (DEP=41). He does not wake up

Mass communication, Mass communication: The well-known exponent of  the...

Mass communication: The well-known exponent of  the role of mass media in development, Dr. Wilbur Schramm, who headed a team of experts  to advise  the development of  infrastr

Explain the rectum and anal canal, Explain the Rectum and Anal Canal R...

Explain the Rectum and Anal Canal Rectum: This is a slightly dilated part of the colon. It leads from the pelvic colon. Anal canal: This is a short canal which leads fro

A field trip to a rock quarry, A field trip to a rock quarry The quarry...

A field trip to a rock quarry The quarry should be visited by the teacher in advance. View how the rock is removed. If the rock is sedimentary, view the layers. Collect rock sa

Perceptual reasoning index, Mr. X was administered the Wechsler Adult Intel...

Mr. X was administered the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV), which is an individually administered test of a person's intellectual ability and cognitive s

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