280chapter 1 intoduction

8/4/2019 280chapter 1 intoduction

1/18

Introduction to food analysisIntroduction to food analysis


2/18

Food analysis objectivesFood analysis objectives

y Developing a theoretical and practicalunderstanding of the methods used toanalyse foods

chemical analysis physical analysis

y to ensure high and consistent quality offoods in the food industry

2


3/18

Proximate analysis of foodsProximate analysis of foods

y Definition

estimation of the main components of a food

using procedures that allow a reasonably rapid and

acceptable measurement of various food fractionswithout the need for sophisticated equipment or

chemicals

3


4/18

Proximate analysisProximate analysis

y Therefore crude estimation; crude fat, crude

protein

not true value but adequate

4


5/18

Proximate analysis of foodsProximate analysis of foods

5


6/18

Further development in foodFurther development in food analysis dueanalysis due

adulterationadulterationy Prior to the 18th century food adulteration

not a serious problem

y

Food adulteration and deception rampant in 18th century

high value foods substituted for cheap often

hazardous materials

6


7/18

FoodFood adulterationadulteration

y adding stone grinds (40%) to flour

y milk samples contained lead chromate (red lead)

y Black pepper: gravel , leaves, twigs

y Vinegar & lemon juice : sulphuric acidy Coffee: roasted cereals, pulses or vegetables,

y Tea: spent, re-dried tea leaves

y Sugar: sand, dust,

7


8/18

y Milk: water, starch, gums and soda

y Beer: poison berry extract gave flavour, colour

and intoxicating effecty Butter: excessive salt & water, potato flour

y Chocolate: starch and ferric oxide

8


9/18

y Quality

the sum of features, characteristics and

properties of a product which bear on its ability

to satisfy stated or implied needs

9


10/18

y Quality control (QC)

operational techniques and activities which

sustain quality of goods and services

x QC staff 100% inspect carcasses at abattoir

x in cannery, check seems, fill weights, pH etc

x laboratory staff carry out analytical tests;

x dairy plant fat test & freezing point

x phosphate test

x direct microscopic counts

x lab staff may conduct sensory analysis

10


11/18

Quality values ofQuality values of foods analysisfoods analysisy Legal

hygiene, additives, residues, contaminants andcomposition

y Nutritive national nutritional guide lines, undesirable

(additives & residues)

y Health over laps with legal and nutritive values

Food Standardsx alert of health hazards during pregnancy

x qualifying the value of food categories

11


12/18

y Technological

convenience foods heat and eat

less processing / perceived fresh

y Sensory like or dislike measurement of quality via

senses

y Socio-ecological

food packaging verses pollution

conversion of rain forest to cow pastures

effluent into water ways

12


13/18

Quality that may be evaluate?Quality that may be evaluate?

y Attribute : which measure qualitative

character of food products

y Variables: which measure quantative

characters of food products

13


14/18

FoodFood chemsitrychemsitry

y Food chemistry is the study ofchemical

processes and interactions of all biological and

non-biological components of foods. The

biological substances include such items asmeat, poultry, lettuce, beer, and milkas

examples. It is similar to biochemistry in its

main components such as carbohydrates, lipids,

and protein, but it also includes areas such aswater, vitamins, minerals, enzymes, food

additives, flavors, and colors.

14


15/18

y discipline also encompasses how products

change under certain food processing

techniques and ways either to enhance or

to prevent them from happening

15


16/18

y And so to study the chemical processes

and interactions of all biological and non-

biological components of foods we need

to food analysis

16


17/18

Food componentsFood components

y Water

y Carbohydrates

y Lipids

y Proteins

y Vitamins

y Minerals

y Enzymes

y additives

17


18/18

y During this course: exploring the different

types of reactions and changes that may

occur during food processing and to

control it by food analysis

18

280chapter 1 intoduction

Documents