Preserving foods, Biology

Assignment Help:

One of man's oldest methods of preserving foods is drying or desiccation. The preservation of foods by drying is a direct result of removal of moisture. Microorganisms need water for growth. The exact amount of water needed for growth of microorganisms varies. This water requirement of microorganisms is best expressed in terms of available water or water activity aw, the vapour pressure of the solution (of solutes in water in most foods) divided by the vapour pressure of the solvent (usually water). Thus aw, for pure water would be 1.00. The water activity depends on the number of molecules and ions present in solution, rather than their size. Thus a compound like sodium chloride, which dissociates into two ions in solution, is more effective at reducing the water activity than a compound like sucrose on mole-to-mole basis.


Related Discussions:- Preserving foods

Modern theory in biology, Modern Theory Naturalistic theory: Accordin...

Modern Theory Naturalistic theory: According to this theory Life originated upon our earth spontaneously from nonliving matter. But there are two significant points in this r

Measures to be taken to avoid fire and in event of a fire, (a)    Bedroom ...

(a)    Bedroom :                    ·           Do not place room heaters near any inflammable materials.                  ·           Do not use heaters

Show the stages in which the cell respiration is divided, Q. What are the t...

Q. What are the three stages into which the cell respiration is divided? The three stages of aerobic cell respiration are glycolysis, Krebs cycle and respiratory chain also kno

What do you mean by periodical, Q. What do you mean by Periodical? A pe...

Q. What do you mean by Periodical? A periodical is a publication appearing at regular intervals. Each issue is called a number and collectively these numbers comprise a volume.

Explain personal risk factors in cad, Explain Personal Risk Factors in CAD?...

Explain Personal Risk Factors in CAD? The personal risk factors are the factors that are specific and characteristic for a particular individual and are non-modifiable in natur

Investigations for diabetes mellitus, Diagnosis of diabetes mellitus which ...

Diagnosis of diabetes mellitus which included history taking, symptoms and signs and various tests which can be done to diagnose a case of diabetes. Diabetes Mellitus (DM) or diabe

Invertabrate zoology, a report on similarities and diffrences between proto...

a report on similarities and diffrences between protozoans and mesazoans

Describe ecological phytosociological, Q. Describe Ecological phytosociolog...

Q. Describe Ecological phytosociological? Field studies are desirable for an understanding of the relationship of any group of plants. If it is not possible to study the plants

What factor helps us in identifying the type of bone graft, What factor hel...

What factor helps us in identifying the type of bone graft to be used? The following factors help us in identyfying the bone graft to be used: i) Whether graft is osteoinduc

Important aspects of nutritional needs during emergency, Define important a...

Define important aspects of nutritional needs during emergency situations? This unit discussed important aspects of nutritional needs during emergency situations and under envi

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