Transcript General Principples

General Principles
*housewife and food nutrients (retains)
•Food processor
•No sharp distinction between home-prepared and
factory-processed foods in their nutritional values
•Are all mothers good cooks?
- destruction of nutrients
- texture and flavors
The term “ processing “ covers an enormous field of widely differing
treatments carried out for a diversity of purposes
* Kind of losses:
1. Intentional losses:
- milled cereals ( bran)
- vegetables are trimmed
- fish eviscerated
- foodstuffs extracted from the raw materials ( starches, sugars, fats,
protein isolates)
2. Inevitable losses ( cooking, blanching, canning, drying, sterilization)
3. accidental and / or avoidable losses ( due to inadequate control)
Are such losses a matter for
concern?
• -Cannot be answered as a generalization
• - no evident malnutrition in the community
( have no significance).
-- the earliest stages of malnutrition are
extremely difficult to diagnose
-- some sections of the community may
be affected more
Nutritionist vs food scientist
• Nutritionist
-- look to the diet as a whole ( no
significance)
• The food scientist
-- any avoidable loss indicates poor
commercial practice
Factory processing vs domestic
cooking
• Direct comparisons are rarely possible
• FP include partial or even complete
cooking so factory losses replace those
that take place in the home
• The situation is very complicated
-- different results for each nutrient ,
food , process and factory …et
-- experimental conditions (
contradictory)
Background
• 1. some losses are inevitable
- preservation
- improvement of palatability
- texture and eating properties
- creation of new products
- removal of inedible parts
- elimination of m/o
- destruction of toxins
* Many of these processes involve heat and water
treatment ( both will result in some losses)
Background
• 2. nutritional losses in food processing
refer generally to all nutrients but
--- vitamin c and to a lesser extent B1
are the most sensitive
--- the other are much more stable
*3. manufacturing and processing losses are
often in place rather than in addition to
what happen in the home
background
• 4. the relative importance of the food in question
as a source of the particular nutrient must be
taken into account ( ignorance of poor source)
• 5. we should look to sections of the community
relying on a small No. of foods as a source of
nutrients.
• 6.we have to be careful when we make
comparison between fresh and processed food
and even between fresh foods.
background
• 7.beneficial effects should be considered
- increase in nutrient availability
- destruction of protease inhibitors
- destruction of toxins……et
*8. losses must be balanced against advantages
- pasteurization of milk ( vit. C, B1,B2)
- So2 as a preservatives ( thiamin)
9. Inadequate methods of assessing nutritive value can
lead to false conclusions .
10. Availability of foods around the year so it is a non-valid
comparison between fresh and processed foods.