Why does the garlic paste turn green?

Many people will find in their daily lives that the garlic paste they make will turn green after being left for some time. This is mainly because garlic contains sulfur-based bioactive substances, which will generate thiosulfinates under the action of allinase. After a series of reactions, the color will change.

1. Garlic cells contain more sulfur-containing bioactive substances. Under the action of alliinase, these sulfides can generate garlic pigment precursors such as thiosulfinate, acrylthiosulfinate, and allylthiosulfinate. These substances undergo a series of reactions to produce garlic pigment. Usually, the first pigment formed is blue pigment (also called allicin). The blue pigment is unstable and gradually transforms into yellow pigment (also called allicin). The coexistence of the two makes garlic appear green. Finally, all the blue pigment is transformed into yellow pigment.

2. This green pigment is a natural anthocyanin pigment. It is not very stable and will gradually turn yellow and lighter during about 25 days of pickling. Many studies have now found that this green pigment in garlic has strong antioxidant capacity and is a high-quality antioxidant. Therefore, eating green pickled garlic is not only non-toxic, but also has the effect of strengthening the body.

3. Therefore, pickled garlic turns green not because it contains chlorophyll, nor does it produce green when exposed to sunlight like plants, but because the garlic produces non-toxic allicin and allicin during the pickling process. When allicin and allicin are mixed together, the garlic turns green. This green color is harmless and beneficial, and it has strong antioxidant properties.