Milk and Milk Products Technology

Defects in whole/skim milk powders their causes and prevention

DEFECTS IN WHOLE / SKIM MILK POWDERS THER CAUSES AND PREVENTION

S.No	Name of the defect	Causes	Prevention
A.	Flavour
1.	Stale/Old	1.Long storage 2.Storage at high temperatures 3.Excessive high pre-heating temperatures 4.Delayed cooling-and-removal of dried product from drying chamber 5.High moisture content during storage	Short Storage Storage at low temperature (24ºC) or below Optimum pre-heating temperature Prompt cooling-and-removal of the dried product from the drying chamber Optimum moisture content during storage
2.	Scorched / Burnt	1.Excessively high temperature (lipase not inactivated) 2.Drum surface has pits 3.Scrapper knives blunt ( in drum drying)	Optimum drying temperature Drum surface kept smooth Scraper knives kept sharp
B	Body and Texture
1.	Lumpy	1.Insufficient drying 2.Absorbtion of moisture (due to exposure to humid atmosphere) 3.Drippage from pressure spray nozzle	Sufficient drying Preventing absorption of moisture (by using moisture-impervious package) Using centrifugal disc atomizer
2.	Caked	1.Absorbtion of moisture	Preventing absorption of moisture (by suing moisture-impervious package)
C	Colour and appearance
1.	Browning/ Darkening of colour	Long storage Storage at high temperature Delayed cooling-and-removal of dried product from drying chamber High moisture content during storage	Short storage Storage at a low temperature Prompt cooling and removal Preventing absorption of moisture (by using moisture-impervious package)

Uses

Skim milk powder

• In the preparation of toned, double toned andrecombined milks;
• In tea and coffee
• In ice-cream manufacture
• In prepared food, breads and rolls, biscuits,cultured milk products and in indigenous sweets.

Whole milk powder

• In the preparation of reconstituted milk
• In tea and coffee
• In baby-food
• In candy and confectionery, bakery products etc.,