TOPIC:FOOD QUALITY PARAMETERS

By: Maryum Atique M. Phill chemistry University of Agriculture FSD.

FOOD QUALITY

Food quality is the quality characteristics of food that is acceptable to consumers.

Food quality is an important food manufacturing requirement, because food consumers are susceptible to any form of contamination that may occur during the manufacturing process.

FACTORS CONTRIBUTING TOWARDS QUALITY OF FOOD

The various factors contributing towards quality of food are :

Appearance Color Taste Odor Nutritional value Adulterants Contaminants (Physical, Chemical &

Microbiological

WHY IS IT NECESSARY TO ANALYZE FOOD PRODUCTS BEFORE OR AFTER PROCESSING?

To know the quality of raw materials and final products.

To understand occurrence of any physicochemical changes during processing or storage.

To ensure purity, freshness and safety of the food products at the time of consumption.

VARIOUS PARAMETERS EVALUATED FOR CERTIFYING QUALITY OF FOOD

In order to ensure the right quality of various food products, several parameters are evaluated as by different methods:

Physical Chemical Packaging materials

PHYSICAL AND RHEOLOGICAL PARAMETERS

Refraction Sieve test Flour

Insect infestation Visual observation Cereals, pulses

Admixture Visual observation Cereals, pulses

Colour on Lovibond scale Lovibond Tintometer Oil, fat,

Bellier turbidity temperature Visual Oils

Optical rotation Polarimeter Sugar, Syrup, Oil & fat

CHEMICAL PARAMETERS

Moisture Hot air oven Vacuum oven Karl Fischer titer Dean & Stark

Most of the food products, Animal feeds

Fat or oil Chemical Most of the food products, Animal feeds

Protein Chemical Most of the food products, Animal feeds

Starch Chemical Starch containing products

PACKAGING MATERIALS

Tin, Chromium AAS Tin plate

Sulphide stain Chemical Food cans

Laquer Physical Chemical Tin cans

Migration tests Chemical Food grade plastics

Heavy metals like Pb, As, Cd, Se, Ba,

AAS Coloured plastics

Water vapour permeability Humidity chamber Plastics

BENEFITS OF FOOD QUALITY PARAMETERS

Benefits of food processing include toxin removal, preservation, easing marketing and distribution tasks, and increasing food consistency.

To increases yearly availability of many foods, enables transportation of foods across long distances and makes many kinds of foods safe to spoilage and micro-organisms.

To reduce the incidence of food borne disease.

CONTINUE;

To improve the quality of life for people with allergies, diabetics, and other people who cannot consume some common food elements.

To add extra nutrients such as vitamins. To offer products that fulfill many different needs:

for example fully prepared ready meals that can be heated up in the microwave oven within a few minutes.

INSTRUMENTAL TECHNIQUES USED FOR ASSESSMENT OF FOOD QUALITY

Classical approach in evaluation of organoleptic quality of food products is the only method used on this purpose.

Classical methods are mainly based on the sensory analysis. This analysis is a perfect tool in carrying out marketing tests of consumers but the limitation is a good complement in the evaluation of organoleptic food properties in instrumental analysis.

The use of appropriate instrumental methods allow for identification of the volatile compounds which influence on the flavor composition of food products.

GAS CHROMATOGRAPHY-OLFACTOMETRY (GC-O)

GC-O is a technique based on sensory evaluation of the eluate from the chromatographic column by trained assessor or group of assessors.

Identification of aroma active compounds is possible on the basis of simultaneous use of second detector. Mostly, second detector function performs mass spectrometer (MS) or flame-ionization detector (FID).

SCHEMATIC DIAGRAM OF GC-O

Fig. 1. Scheme of gas chromatograph coupled with olfactometric detector

METHODS OF GC-O

ELECTRONIC NOSE

Electronic nose is a device consisting of a set (matrix) of electrochemical sensors, selective for certain volatile compounds.

The instrument is equipped with appropriate system of pattern recognition capable of identification of simple and complex odors.

SCHEMATIC DIAGRAM ELECTRONIC NOSE

For the odor of a tested product responsible are not only single aromatic compounds but also their complex mixtures. They give a resultant aromatic effect which is present in perfumes.

It has a number of gas sensors that form matrix . These sensors act as sensory neurons and Artificial Neural Networks (ANN) constitute its main part . Microprocessor or computer play a role of a brain.

There is a resultant signal from all the sensors collected in the computer and an electronic pattern of the odor is created.

Practical applications of electronic nose in food industry

FEATURES AND DISADVANTAGES OF THESE TECHNIQUES

Both presented techniques are better than classically applied in the industry. However, more promising seems to be e-nose. It is due to the following features:

Short time of analysis, high sensitivity and reproducibility, objective, identification of odors, possible in situ analysis (portable devise).

E-nose system has also a few disadvantages, Ageing material of sensors, possibility of sensors

poisoning, in some cases humidity influence to sensor responses.

The use of these methods also allow for discrimination raw material used in the production.

DRAWBACKS Food quality parameters includes the following

drawbacks, To affect its nutritional density, the amount of

nutrients lost depending on the food and method of processing.

Vitamin C, is destroyed by heat and therefore canned fruits have a lower content of vitamin C than fresh ones.

Large mixing, grinding, chopping and emulsifying equipment, inherently introduce a number of contamination risks.

Large food processors will utilize many metal within the processing stream, metals may be dangerous for our health.