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(food engineering)
A hot-water or steam direct-scalding treatment of raw foodstuffs of particulate type to inactivate enzymes which otherwise might cause quality deterioration, particularly of flavor, during processing or storage.



(1) In the food-processing industry, blanching is the processing of fruits and vegetables in hot water. This prevents them from darkening and makes the vegetable cells permeable to sugar molecules, which facilitates jam-making. Blanching is also used in the production of raisins and the withering of grapes in the production of sweet and ordinary wines. Blanching for one to three minutes shortens the withering process two to three times.

(2) In the tanning industry blanching is used to remove the residues of subcutaneous cellulose tissues from the lower (flesh side) of skins. After blanching, the surface of the flesh side becomes very smooth, and after dressing and glazing, it becomes lustrous. Skins are also blanched to achieve uniform thickness and to remove defects that cannot be removed by polishing after the application of coatings on the outer side of the skin.

References in periodicals archive ?
Some think differently, however, claiming that provided produce is garden-fresh and processed the same day it is picked, blanching is quite unnecessary.
Blanching kills bacteria and destroys enzymes that could taint food.
The sites were occluded for six hours and visual scoring and colorimetric measurements of skin blanching (vasoconstriction of superficial skin blood vessels) were performed at 6, 8, 10, 12, 24, 28 and 32 hours after product application.
Blanching destroyed 95 percent of the disflavoring enzymes in kernels and 68 percent of the enzymes in the cob of cored corn, almost double those destroyed by the traditional approach.
Morama beans were cracked manually then pre-processed using the blanching pretreatments indicated in Figure 2.
Blanching the peeled potatoes is one of the processing steps, whereby sugars are removed.
Blanching cleans off dirt and organisms that could cause the food to lose its flavor and texture.
Pretreatment of food materials which includes; blanching, chemical pretreatment, osmotic dehydration, soaking in ascorbic acid before or on drying have been investigated to improve the effect of drying and give eventual dried products of good nutritional quality [5, 9, 10, 11].
Like endive, it can be bitter when green, so blanching helps.
However, various processing conditions or factors used during canning such as the time-temperature combination for the processing, headspace of the can, pressure at which the food is processed, quality of the seam, blanching, exhausting as well as the choice of the processing medium can affect the quality of the processed foods.
Blanching fruits and vegetables in calcium chloride solution increases their firmness.
The theory is that blanching (plunging vegetables into boiling water for a couple of minutes before freezing) destroys bacteria which encourage decomposition, thus affecting the frozen lifespan.