nutrition - food test

8/7/2019 Nutrition - Food test

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� The test for the presence of proteins in food

samples is known as theMillons test.

� A red precipitate is formed when protein (such

as egg albumen) is heated together with

Millons reagent.



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Is a diet that contains all classes of food in the right

amount according to our body needs.

A balanced diet contain :

a) Carbohydrates (55% - 65%) and fats (20% - 35%)

to provide energy.

b) Proteins (10% - 15%) for the growth and repair

of damaged tissue.

c) Sufficient vitamins and minerals to maintaingood health.

d) Water and fibre to maintain liquid equilibrium

in the body and encourage peristalsis.



� Individual who has a bigger body needs more

calories than an individual with a smaller body.

� An individual who is physically activeneeds more calories than an individual

who is inactive.



� A healthy person requires less energy than a sick person.

� Sick person need to overcome infections, maintain body

temperature and to repair diseased body tissues.

� A person living in a cold country needsmore energy to maintain his body

temperature.



� Males need more energy than females of the same age

group.

� The metabolic rate of males is higher than that of females.

� Children and adults need more energy

than babies as they are more active.



What is calorie?It is the amount of energy stored in food.

What is Calorific value or energy

value?It is the amount of energy produced by one gram

of a particular type of food.

SI unit is joules (J) or calories (cal).

1 calories (cal) = 4.2 joules (J)1 kilojoules (kJ) = 1000 joules (J)

1 kilocalories (kcal) = 4200 joules (J)

= 1000 calories (cal)



Class of food Energy value (kJ /g)

Carbohydrates 17

Proteins 18

Fats 39

Energy values of the main food classes

Food Energy

value

Food Energy

value

Rice 546 Bread and

butter

1400

Rice

Vermicelli

1474 Laksa 800

Chickenrice

2300 Nasi lemak 2500

Curry puff 360 Papaya 164

Energy values of some local food



Food Calorific value

per 100g (kJ)

Tosei 154

Nasi Lemak 492

Orange juice 202

Meat Dumpling 235

Milk 276

Guava 290

Table 1

Meal A Meal B

100 g t s i 180 g at li g

150 g asi l ak 100 g ilk

200 g ra g j ic 120 g g ava



Individual

� Newborn baby� Children

� Pregnant women

� Office worker

� Factory worker

Daily energyrequirement

� 2000� 7500

� 10000

� 11000

� 12500

Gender Age

Group

Suggested calorific value of

food for daily consumption

Males 15 ± 18 12 600

19 ± 24 12 180

Females 15 ± 18 9 240

19 ± 24 9 240



Is necessary for :

a) Supplying the required energy.

b) Balanced body growth.

c) Maintain health of the body.

d) Repair and replace old or damaged tissues.

e) Preventing deficiency diseases such as

scurvy and rickets.



� The food that we eat will be digested, absorbed into thebloodstream and transported throughout our body.

� Food consists of complex substances ( carbohydrates, protein

and fats)

� These substances are large and complex ;cannot be absorbedby body.

� So all these food need to be digested first before they can be

absorbed by the body.



� Digestion : process breaking down food

molecules into smaller molecules readily

be absorbed by the body.

� Digestion is carried out by the digestive

system.

� Digestive system consists of :

i. The alimentary canal

ii. The accessory organs



PHYSICAL DIGESTION

Big pieces of food are broken

down into smaller pieces by teeth.

CHEMICAL DIGESTION

Involves the action of enzymes on

the food.



� Enzymes : proteins that speed up

the process of digestion.� AMYLASE ± help in the digestion of carbohydrates

� PROTEASES ± help in the digestion

of protein� LIPASE ± help in the digestion of

fats



Characteristics

Required insmall quantity

only

Specific enzymesact only on specific

foods

Functions bestat body

temperature

Not destroyedat the end of

digestion

Specific enzymesact only in specificacidic or alkaline

conditions.



� The bolus moves down

the oesophagus.

� The muscular wall of the

oesophagus contracts and

relaxes to produce a

wavelike movement.

� This movement is calledPERISTALSIS.

� Peristalsis pushes the

bolus from oesophagus to

stomach.



Food is mixed with gastric juices .

Gastric juices contain :

:

a) Providing an acidic medium for the action of enzymes.

b) To kill bacteria that is found in food.

c) To stop the action of amylase enzyme.

Pepsin : Proteins peptones.

Rennin coagulates milk in stomach to help in the enzymic action of pepsin.

Partially digested food is called chyme.



The first part of the small intestine.

Chyme is mixed with bile and pancreatic juice.

: greenish liquid produced by the liver and stored in the gall bladder.

:

a) Emulsifies fats into smaller oil droplets. Known as emulsification.

b) Does not contain enzyme.

c) Provides an alkaline medium for the action of enzymes.

Pancreatic juice contains amylase, protease and lipase.

Amilase : Starch Maltose

Lipase : Fat Fatty acid + glycerol

Protease : Protein Polipeptida



Food that is digested in the duodenum enters ileum.

Food is mixed with intestinal juice.

Intestinal juice contains all the enzymes to complete the digestion of

carbohydrates, protein and fats.

Digestion of food ends in the small intestine.



The end products of digestion are :

Class of food being digested End products

Carbohydrate Glucose

Proteins Amino acids

Fats Fatty acids and glycerol

The summary of the digestive processes in the alimentary canal :

Classes of

food

Part of alimentary canal

Mouth Stomach Duodenum Lower part of small

intestine

Carbohydrates / X / /

Proteins X / / /

Fats X X / /

Fibre X X X X



The summary of process of chemical digestion in the human

alimentary canal :Part of

alimentary

canal

Rembesan Sifat-sifat

rembesan

Enzim Tindakan pencernaan

Mulut Air liur Beralkali Amilase Kanji ± Maltosa

Perut Jus gaster Berasid Protease Protein ± Pepton

Duodenum Jus

pancreas

Beralkali Lipase Lemak ± asid lemak +gliserol

Amilase Kanji ± maltosa

Protease Protein ± Pepton

Hempedu Beralkali Tiada

enzim

Lemak ± titisan lemak

Bahagian

bawah usus

kecil

Jus usus Beralkali Protease Polipeptida ± asid amino

Lipase Lemak - asid lemak + gliserol

Laktase Laktosa ± galaktosa + glukosa

Maltase Maltosa ± glukosa

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