Functional Dehydrated Foods for Health Preservation

Table 7

Phytochemical losses during the pretreatment and/or drying process [166].

Phytochemicals/vitamins	Product	Pretreatment	Drying method	Phytochemicals/vitamins Losses	References
Carotenoids	Carrot	With blanching treatment	Fluidized bed dryer	15.7% carotenoids	[167]
	Carrots, broccoli and spinach		Microwave drying	63% carotenoids	[168]
	Paprika	Without treatment (without enzyme inactivation)	Flow dryer	80% carotene	[160]
	Paprika	With blanching treatment	Flow dryer	5% (depends on the product)	[160]
Lycopene	Tomato		Osmotic-vacuum drying	Better than vacuum drying and air drying; 8.1 to 20.9%	[169]
	Tomato pulp			Depends upon the conditions	[170]
	Carrots		Inert gas drying	No effect	[171]
Vitamin C	Carrot	Blanching treatment	Vacuum, microwave, air and freeze-drying	37% before drying	[161]
	Apple and strawberry	60% Sucrose solution	Microwave vacuum	40%	[172]
Vitamin C and carotenoids	Carrot	Blanching with sulphite and L-Cysteine-HCl	Fluidized bed dryer	L-Cysteine-HCl retained highest content of vit. C; Na metabisulphite able to reduce oxidation of carotenoids	[173]
Carotene and vitamin C	Carrots, paprika, potatoes		Inert gas drying	15% carotene; 13% vit.C	[162]
	Strawberry and carrot			Refractance window similar to freeze-drying	[174]
Vitamin C and PUFA’s	Seaweed		Sun-drying, oven-drying, and freeze-drying	Much lower in freeze-drying than oven and sun-drying	[175]
Tocopherol, carotenoids and vitamin C	Paprika	Blanching by steaming or hot air	Flow dryer	Better retention	[160]
Total phenolic content and antioxidant activity	Apple		Microwave drying	39% (TPC) and 30% (AA)	[176]
D3 (milk powder)	Milk		Spray-drying	Negligible losses	[177]
Folic acid	CMC model system		Spray-drying	Increase folate retention	[178]
Thiamine, riboflavin and niacin	Spaghetti		Convection air	Loss of vit.​; Drying 16–28%	[179]
Vitamin E	Whole meal wheat flour		Drum dryer	More loss of vit. E during scalding (75%) than during drum drying (15%)	[180]