Transcript Food preservation

Introduction: Food preservation
 What Are Foods?
 Foods are materials (raw, processed, or formulated) that
are consumed orally by humans or animals for growth,
health or pleasure.
 Generally, there is no limitation on the amount of food
that may be consumed (as there is for a drug in the form of
dosage).
 This does not mean that we can eat any food item as
much as we want. Excessive amounts could be lethal, for
example, salt, fat, and sugar.
 The preservation method is mainly based on the types of
food that need to be prepared or formulated.
 Definition of “Food preservation” :
Food preservation involves the action taken to maintain
foods with the desired properties or nature for as long as
possible.
 First, it is important to identify the properties or
characteristics that need to be preserved.
 One property may be important for one product, but
detrimental for others. For example, the consumer expects
apple juice to be clear whereas orange juice could be
cloudy.
 Why Preservation?
 To overcome inappropriate planning in agriculture
 Produce value-added products
 Provide variation in diet
 In food preservation, the important points that need to
be considered are:
A: The desired level of quality
B: The preservation length
C: The group for whom the products are preserved
Definition of Quality???
 A: The desired level of quality
 Definition: Quality is …
“the degree of fitness for use”
or
“the condition indicated by the satisfaction level of consumers”
 Quality is an deceptive, ever-changing concept.
 When food has deteriorated to such an extent that it is
considered unsuitable for consumption, it is said to
have reached the end of its shelf life.
 In studying the shelf life of foods, What is more
important?
Quality or Safety?
 In studying the shelf life of foods: Safety is the first attribute,
the second is other quality.
 The product quality attributes can be quite varied, such as:
 Appearance
 microbial characteristics
 Organoleptic properties
 …
 Organoleptic:
 Sensory properties that can be detected by the sense
organs.
 Include:
1) Taste
2) Texture
3) Astringency
4) Aroma
1- Taste
 The tongue can distinguish five separate tastes:
1) sweet
2) salt
3) sour (or acid)
4) bitter
5) savoury (or umami)
 Sweet, salt, sour and bitter are classic tastes.
*Savoury: means tasty, having a pleasant flavor
*Umami:
 The Japanese name for a savoury flavour, now
considered one of the five basic senses of taste.
 It is name given to the special taste of monosodium
glutamate (the sodium salt of glutamic acid), some
other amino acids, protein and the ribonucleotides.
 These are flavour enhancer: A substance that
enhances or potentiates the flavours of other
substances without itself imparting any characteristic
flavour of its own.
2- Texture
physical properties
3- Astringency
 (perceived in the mouth)
 The action causing a contraction of the epithelial tissues of
the tongue
 Due to tannins (tannic acid) found in a variety of plants
such as unripe fruits, tea, …)
4- Aroma (perceived in the nose)
 Loss of quality is highly dependent on types of :
 Food and composition
 Formulation (for manufactured foods)
 Packaging
 Storage conditions
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B: The preservation length
After storage for a certain period, one or more quality attributes
of a food may reach an undesirable state.
At that time, the food is considered unsuitable for consumption
and is said to have reached the end of its shelf life.
“Best-before date” is set shorter than the shelf life with a good
margin.
How ever, if product stored at the recommended conditions it is
usually safe and palatable to consume a product a long time
after the best-before date.
Products may be marketed with the production date “pack
date” and “best-before date.”
Alternative markings is “expiration date”, which may be closer
to shelf life than “best-before date”.
C: The group for whom the products are preserved
 Nutritional requirements and food restrictions apply
differently to different population groups.
 Food poisoning can be fatal, especially in infants,
pregnant women, the elderly, and those with depressed
immune systems.
 TQM =?
 HACCP=?
 ISO=?
 GMP=?
 GHP=?
 TQM = Total quality management
 HACCP Hazard Analysis and Critical Control
 Points
 INTERNATIONAL STANDARDS ORGANIZATION
(ISO)
 Good Manufacturing Practice (GMP)
 Good Hygiene Practice (GHP)