IMPORTANCE OF WATER AS A NUTRITIONAL FACTOR

Ordinarily, water does not attract attention as a nutrient. This is because it is so common and thus people tend to overlook it.

Water accounts for about 55-70 percent of total body weight. This shows how important it is , as a nutritional factor.

If water is eliminated from diet completely, death will occur in a matter of days whereas if any other nutrient is eliminated from diet, people can survive longer.

Water is by far the most critical of all nutrients. It is an essential component of all cell structures and is the medium in which all the chemical reactions of cellular metabolism takes place.

The water available to the body is of two kinds - water taken from outside with or without food and water generated within the body.

The water generated within the body as a result of oxidation of foodstuffs is referred to as metabolic water. This accounts for nearly 15 percent of the daily total water available from ordinary intake of food and drinks.

Since water is compatible with many food substances, it serves as ideal medium of transporting nutrients to the cell where cellular mebabolism takes place.

Water is involved in the proper maintenance of body temperature.

Water helps to distribute heat evenly within the body because of its high conductivity property.

It also helps to remove excess heat by vaporization process.

Furthermore, water plays a lubricating role in body movement. It serves a cushioning device that facilitates movement of the joints. This is because water is not readily compressible and moreover, it has flow characteristics.

Water is also actively involved in various metabolic reactions, particularly those involving hydrolysis and hydration reactions.

SOURCES OF WATER: 

Water is available as drinking or portable water in the homes. Water is also available in all the beverages one drinks.

Another good souce of water is the food we eat. Watery foods such as pap, soups, porridge, are good sources of water.

Even the foods that appear to be dry still contain some quantity of water. For example, a piece of bread contains as much as 35% water content.

On the average, solid foods contribute between 20 and 50 percent water needed daily.

Another source of water is the metabolic water which is generated within the body. For instance, when amino acids are utilized for the synthesis of proteins, water is produced as a by-product. Similarly, formation of fats leads to production of water and so on.

DAY 19, 5 ESSENTIAL WISDOM TOOLS FOR A FRUITFUL LIFE

1. The most important quality

of leadership is the "reality

principle."

- JACK WELCH


2. You develop new beliefs by

taking actions consistent with

those beliefs.

- BRIAN TRACY


3. Your main job in life is to create the  mental equivalent

within yourself of what you want to realize and enjoy in your

outer world.

- EMMET FOX


4. The Law of Reversibility in psychology and metaphysics says,

"You are more likely to act yourself into feeling a particular way

than you are to feel yourself into acting."


5. Within every difficulty or obstacle, there is the seed of an

equal or greater advantage or benefit.

- NAPOLEON HILL


GOD BLESS. 

FISH(FOOD OF ANIMAL ORIGIN) DETERIORATION & THE PRESERVATION PRINCIPLES

FISH DETERIORATION

Fish tissue is more perishable than animal tissue. This is because the proportion of connective tissue proteins in fish is 3-5% lower than that of meat and 8-10% lower than that of stockfish.

Also, the denaturation temperature of fish connective tissue collagen is much lower than the corresponding beef protein.

The fish myosins also denature much more rapidly than beef or chicken myosins kept under the same conditions.

Besides, fish struggles when caught and use up virtually all the muscle glycogen. Consequently, the lactic acid content of the muscles necessary to exert preservative action becomes depleted.

As soon as fish dies, it begins to deteriorate.

Fish flesh contains between 0.2-2.0% of trimethylamine oxide (TMAO). This compound is an odour precursor and is broken down by spoilage bacteria after death to trimethylamine (TMA), dimethylamine (DMA) and monomethylamine (MMA). TMA is the main contributor to the smell of stale fish.

Four main factors are responsible for fish spoilage. These factors are:

1. Autolysis:  
Autolysis usually precedes bacterial spoilage and involves the breakdown of protein and lipids to amino acids and fat by muscle enzymes.

The amino acids produced are used by microbes for proliferation.

2. Activity of micro-organisms: 
This is the chief cause of decomposition of fresh unprocessed fish muscle.

While the flesh of healthy live fish is generally sterile, large numbers of bacteria are harboured in the surface slime and digestive tracts of living fish.

When the fish is killed, these bacteria attack the constituents of the tissues and grow relatively rapidly, resulting in the production of off-flavours and odours such as TMA.

3. Chemical deterioration: 
The fats of fish are highly unsaturated and become easily oxidized. This results in rancid off-odours and flavours.

Furthermore, the fats of fish contain phospholipids rich in trimethylamine oxide.

TMA is split from the phospholipids by bacteria and natural fish enzymes to produce a strong fishy odour.

4. Attack by insects: 
Flesh flies, blow flies and various beetles attack fish and cause considerable deterioration.

Troublesome scavengers such as mice, rats, hawks, cats, owls, dogs and crows eat up fish and obnoxious vermins like bugs, fleas, lice etc. Feed on fish flesh and contaminate it with bacteria, resulting in a rapid deterioration in the quality of the fish.


THE PRESERVATION PRINCIPLES

As soon as fish dies, it begins to deteriorate. This natural process is irreversible and the preservation principle is to slow down the deterioration, and increase the overall quality and storage life of the fish.

The general principles involved in the preservation include:

1. Scrupulous cleaning and hygiene in handling the fish caught.

2. Rapid and effective processing by:
a). Reducing the moisture content by drying, salting and smoking.

b). Lowering the temperature by rapid freezing to at least -10°c in not more than two hours.

c). Glazing to prevent drying.

3. Good packaging, storage and transport practices: Storage of frozen fish at -18 to -22°c is adequate to preserve the quality for up to 18 months.


REFERENCES

Fox, B. A. and Cameron, A. G. (1989). Food Science, Nutrition and Health. 5th ed. Edward Arnold; A division of Hodder & Stoughton, London.

Ihekoronye, A. I. and Ngoddy, P. O. (1985). Integrated Food Science and Technology for the Tropics. Macmillan Publishers, London.

CASSAVA(FOOD OF PLANT ORIGIN) TOXICOLOGY

Cassava contains the cyanogenic glucoside, linamarin and lotaustralin; linamarin being present in quantity up to 90% of the total.

These are hydrolyzed by the enzyme, linamarase to yield free hydrogen cyanide. In the intact cassava tissue, linamarin is separated from the enzyme linamarase.

Cyanide is exceedinly toxic to man and domestic animals if consumed in amounts in excess of 25-30ppm.

Cassava tubers must therefore be detoxified and the liberated cyanide subsequently eliminated before consumption.

The elimination of cyanide in different cassava-based foods is based on the fact that free cyanide is both water soluble and heat volatilizable while bound cyanide can be converted by enzyme or heat hydrolysis to give water soluble, heat volatilizable hydrogen cyanide.

The detoxification mechanism involes: (1) The conversion of bound cyanide to free cyanide by enzyme and heat hydrolysis.
(2). The removal of free cyanide by repeated leaching with water and by heat volatilization.

The various process steps associated with the detoxification of different cassava-based products include:
1. Grating which exposes the glucoside to linamarase for hydrolysis to prusic acid.

2. Fermentation, during which linamarin and lotaustralin are broken down into harmless components.

3. De-watering, which eliminates a substantial quantity of hydrogen cyanide.

4. Cooking and heat toasting, which can also destroys hydrogen cyanide.

Residual cyanide in most cassava products can be neutralized by the enzyme, rhodanase- an organic catalyst found in human cells.

Vitamin B12 from food of animal origin can also neutralize residual cyanide.

With cystine obtained in the diet, the human body is also capable of counteracting hydrogen cyanide.

The consumption of cassava products with high levels of cyanide over a long period has been linked to ailments such as "tropical ataxic neuropathy" and "goitre".


REFERENCES

Adeyemi, I. A. and Balogh, E. (1985). Biotechnology in Food Processing: Prospects in Nigeria. Nigeria Food Journals vol 2, nos 2&3.

Brownsell, V. I., Griffith, C. J. and Eleri, J. (1992). Applied Science Food Studies. Longman Scientific & Technical; UK

DAY 18, 5 ESSENTIAL WISDOM TOOLS FOR A FRUITFUL LIFE

1. Your beliefs don't make you a better

person but your behaviour does.


2. Believe in your dreams and they may come

 true. Believe in yourself and they will come

true.


3. Success is the ability to go from one failure to another with no

loss of enthusiasm.


4. Forget what hurt you but never forget what it tought you.


5. Don't think outside the box but think like there is no box.


GOD BLESS.