hot summer, playing to enjoy a cup of fresh fruit and vegetable juices, it can be said both healthy fashion. Natural colors of different fruits and vegetables into juice, the color should be bright in this beautiful, beautiful place in the cup is a pleasure to look at. However, in the production of a headache when果菜汁one thing, that is, making a slurry, or squeeze the juice, in a few minutes to a few dozen minutes, the color will become darker browning quickly, it looks great loss of appetite.
why good fruit and vegetable juices will be browning it? This is because many fruits and vegetables contain "polyphenols" and "Phenoloxidase." Normally, these two types of material be segregated in cells in different regions, it is difficult to meet each other, so no problem there will be no reaction. Once the juice when the destruction of the cell, these two types of material will be able to meet, together with adequate oxygen in the air, will soon oxidase enzyme catalytic colorless polyphenols oxidation reaction happened to generate colored "quinone substances. " These quinones can each polymer material, so that more and more deep color. Beginning at pink, then become light brown, brown and even black. Cut potatoes, sweet potato, eggplant, apple and other fruits and vegetables when the black, all are derived from a token.
know the truth, after someone may ask: Why market selling fruit juice, vegetable juice and frozen French fries, such products are not brown it? This is because at technology which juice taken some special measures to protect them. There are several ways to no more than: first, short-lived first in boiling water "blanching" and let Phenoloxidase "inactivation" can no longer catalytic oxidation reaction; are at two to add a small amount of juice when sulfite, lemon acid, vitamin C and other harmless substances, which can inhibit some phenoloxidase activity, and some can and promote the oxidation of metal ion binding, and some can put a colored material after oxidation reduction was colorless substances; three are after Absorption role, except for some brown material. After several efforts, the product can be maintained on basically you beautiful color.
at home in freshly squeezed fruit and vegetable Although it is not possible to take such a complex approach, but the basis of the same reasoning, you can add some juice when Vitamin C (drug store to buy vitamin C tablets can be crushed), or pear, apple and cut into small pieces first, in boiling water to the semi-hot and then juice. However, some heated变味easy fruit juice should not adopt this approach.
Although difficult to look the browning of the juice, causing browning of the material, but are components of antioxidant health. Say so, because the color not to discriminate against possible browning of these fruits and vegetables ah. Apart from the color change, the at久存, these components may also bring juice turbidity and sedimentation, but these are natural phenomena, and no prejudice to the health of hazardous substances.
Of course, if those who do not select easy browning to juice fruits and vegetables is the simplest way to you. These raw materials, including citrus, strawberry, tomato, carrot, mango, watermelon and so on. They will be browning, but a rate that does not like to watch on apple browning to a few hours or even longer can see the obvious changes.
(two days will be introduced to two fruit and vegetable taste, with a total of U.S. goods!)
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