2. GROUP-D
SAFFER ALI LAKHO 2K18-PT-189
MUSHTAQUE SAMEJO 2K18-PT-167
MUQEEM ABBASI 2K18-PT-165
SHAOIB NIZAMANI 2K18-PT-154
M.WARIS NIZAMANI 2K18-PT-158
ABDULLAH BHUTTO 2K18-PT-134
YASIR ABBAS BHATTI 2K18-PT-231
SAJJAD ALI PANWHAR 2K18-PT-196
3.
4. Perishability:
Perishability refers to the quickness
with which a food gets spoilt. Foods can be
classified into three groups depending on how long
they can be kept without any treatment.
5. There are three types of food on the basis of
perishability.
1) Perishable food.
2) Semi Perishable food.
3) Non Perishable food.
6. 1) Perishable foods: Perishable foods can be
kept at room temperature for only few hours or 1 or 2
days before spoiling.
It contain moisture about
(80 to 95%).
=>For example: Milk and milk products, meat,
fish, poultry, fruits, leafy vegetables and cooked
food. These foods keep well under refrigeration at
household as well as commercial level.
7. In general, the most perishable foods contain a high level of protein or
have moisture and special methods are used to preserve such foods. The
rate of spoilage varies with the temperature, moisture and or dryness of
the environment.
=>Storage of perishable foods should be
done by keepingfollowing points in mind.
Flesh foods like meat, chicken and fish
need to be kept frozen at -60°C in a deep
Freeze for long term storage.
These foods should not be left at room
temperature for more than an hour or
two.
Organ meats tend to spoil Faster than muscle meat.
8. o Ground meats spoil faster because of
high surface area
exposed to
contamination.
o Eggs are best kept in a
cool place or in a basket
in an airy room refrigerator
o Never wash eggs before storing. Store
eggs with their pointed end downwards.
9. Do not wash fruits before storing as they spoil faster.
Remember not to, refrigerate bananas, pineapples, papayas
and avocadoes, as
these fruits undergo
undesirable changes
in texture and flavor at
refrigerator
temperature. Most
other fruits keep well,
when refrigerated.
Vegetables must be
kept in plastic bags to prevent drying by evaporation, if stored
in a refrigerator
10. The keeping quality of a vegetable depends upon its
nature. All other vegetables keep well in a cool place with
relatively high humidity in a basket covered with a damp
cloth.
Leafy vegetables wilt and deteriorate within minutes of
buying unless they are kept wrapped in a damp cloth or
inside a plastic bag in the refrigerator where in they last
for more than a day or two.
Milk in boiled form can be kept at room temperature for
6 to 12 hours during winters. Inside a refrigerator milk
can last 3 to 4 days or even more in closed container.
11. 2) Semi -perishable foods :
It contain moisture about (60 to 75%).
Semi -perishable foods can be stored for a couple of weeks or even a
month or two without any detectable
signs of spoilage. Temperature and
humidity of the environment again
affects the shelf stability of such foods.
Proper handling and storage can result
in fairly long storage without spoilage.
=>Examples Some fruits and
vegetables like citrus fruits, aonla,
apples, pumpkin, roots and tubers, yams, potatoes, onions, garlic etc.
12. =>Following points should be keep in mind
while storing semi-perishable foods.
Processed cereal products develop an off- flavour or are
infested by insects very easily if not taken care. Therefore,
they should be sieved and cleaned of all such contamination,
exposed to the sun for a few hours, allowed to cool and then
stored in tightly covered bottles or other containers.
Especially onions and potatoes should be stored in a cool,
dry and airy place to prevent them from developing moulds
or growing shoots. They are best hung up from the ceiling in
a wire or plastic-mesh basket, or kept in mesh containers
which permit air circulation.
13. Nuts become rancid and get infested with
insects very easily, therefore, they should be
bought in large quantities only when storage
space is available.
Fruits like apples, oranges and semi-ripe
mangoes do last for a few weeks and should be
put in a basket lined and covered with paper to
prevent them from drying up. They need a cool
environment to last long.
14. 3)Non- perishable foods :
It contain moisture about (10 to 22%). Non-
perishable foods will keep for months or years without spoiling
unless handled and stored carelessly.
=> Examples of such foods are all
preserved food products (canned,
dried, pickled etc.), whole cereal,
pulse and millet grains, oil seeds,
nuts, fats and oils, honey, sugar,
jiggery, salt, some spices and
essence.
15. =>Following points should be followed while
storing non-perishable foods:
Food should be carefully cleaned i.e. free from gravel,
husk and other foreign matter etc. and dried thoroughly
in the sun/ drier before storage.
Storage of foods should be done in clean containers
with tight-fitting lids.
Containers can be made of tin, aluminum, plastic or
glass.
Clay pots or gunny bags may also used in case of large
quantities.
16. A dry, cool and dark area should be chosen for storage of
non-perishable foods
The perishability of food dictates to a considerable extent the
preservation techniques that are
used to keep that food in good
quality.
In case of non-perishable foods,
preservation techniques are
dedicated to keeping out insects,
rodents and other pests and keeping
the foods dry to prevent it from
becoming moldy.
17. Perishable and semi-perishable foods depend a great deal on
the technologies of refrigeration, drying, freezing, canning and
the use of chemical preservatives to give shelf stability.
These treatments can make such food commodities keep for
many months or years if they are performed properly.
18. pH is a measure of hydrogen ion concentration, a measure
of the acidity or alkalinity of a solution. The pH scale
usually ranges from 0 to 14. Aqueous solutions at 25°C
with a pH less than 7 are acidic, while those with
a pH greater than 7 are basic or alkaline.
19. Most foods are derived either from plants or from animals.We are
concerned with foods of plant origin and are known as vegetables
or fruits based on their use. These foods have different pH and
are classified as low acid foods, medium acid foods, acid foods
and high acid foods.
a) Low acid foods:
The foods having pH above 5.3 are called low acid
foods.
20. Examples of Low-acid foods
Alkaline (or neutral) foods and
beverages you can incorporate into your diet include:
Soy, such as miso, soy beans, tofu, and tempeh
unsweetened yogurt and milk
most fresh vegetables, including potatoes
most fruits
herbs and spices, excluding salt, mustard, and nutmeg
beans and lentils
some whole grains, such as millet, quinoa, and amaranth
herbal teas
fats like olive oil, avocados, nuts, and seeds
21. b) Medium acid foods:
The foods which have pH between 4.3 and 5.3 are
called medium acid foods.
For example: asparagus, beets, pumpkin, spinach etc.
•Cranberries
•Pomegranates
•Olives, ripe
•Corn, fresh
•Chicken
•Liver
•Buffalo
•Catfish
•Eggs, whole
22. c) Acid foods:
Foods which have pH between 3.7 and 4.5 are called acid foods.
Foods containing acid include:
Meat
Grains
Dairy
Unsprouted beans
Sunflower and pumpkin seeds
Nuts
Carbonated drinks
Alcohol
Coffee and other caffeinated drinks
Sweeteners
Refined table salt
Tobacco
23. d) High acid foods
Examples of High-acid food and drink
If you suspect you have problems with
acidity, you can make changes to your diet to help improve symptoms.
Foods that are considered acidic must have a pH level of 3.7 or above.
Foods that tend to cause more acidity in the body and that you
may need to limit or avoid include:
grains
sugar
certain dairy products
fish
processed foods
fresh meats and processed meats, such as corned beef and turkey
sodas and other sweetened beverages
high-protein foods and supplements
24. Effect of pH on food:
The pH of foods is a major
factor affecting their appearance, texture, flavor, nutritional value,
and safety. The pH values in food range from 2 to 7 and
alkaline foods are rare. The reason for such values of pH is that the
acids and bases naturally present in food tend to be weak.
Certain food groups are considered acidic, alkaline, or
neutral:
Acidic: meat, poultry, fish, dairy, eggs, grains, alcohol.
Neutral: natural fats, starches, and sugars.
Alkaline: fruits, nuts, legumes, and vegetables.
25. Microorganisms, including yeasts, molds and bacteria are
sensitive to a food's pH. Very low or high pH values will
prevent microbial growth. As a practical matter, no
unprocessed food has a pH value high enough to offer
much preservative value.
The lower the pH reading, the more acid the food. In order
to preserve foods with acidity, the regulation requires
the pH to be 4.6 or below. At these levels, toxins formed by
the deadly organism causing botulism are inhibited. We refer
to foods which have readings greater than pH 4.6 as low-
acid foods.
26. Maintenance of pH in Human body
The food you eat doesn't affect
the pH of your blood, Your body maintains a neutral pH of about
7.4 from natural bodily functions, like breathing and urinating.
The alkaline diet recommends limiting protein, but Texas A&M
reports that healthy proteins are necessary for muscle growth and
weight loss. Plus, these nutrients help your body excrete acid
through urine.
Most fruits and vegetables tend to be base food items, which
means they're above 7 on the pH scale.
27. Here are the pH values of some common foods:
Apples (red delicious): 3.9
Bananas: 4.5 to 5.2
Strawberries: 3.0 to 3.5
Oranges: 3.1 to 4.1
Chicken: 6.5 to 6.7
Freshwater fish: 6.6 to 6.8
Tuna fish: 5.2 to 6.1
Milk: 6.2 to 7.3
Bread: 5.3 to 5.8
Butter: 6.1 to 6.4
Cabbage (pH: 5.20–6.80)
Beets (pH: 5.30–6.60)
Corn (pH: 5.90–7.50)
Mushrooms (pH: 6.00–6.70)
Broccoli (pH: 6.30-6.85)
