1. Many families in China have a tradition of making "Laba garlic". In the twelfth lunar month, garlic is peeled, washed, peeled, poured with rice vinegar and sealed in a small altar. When it is opened on New Year's Eve, it is made into a "Laba garlic" with pleasant greenery and delicious garlic flavor. The production process of "Laba garlic" did not see sunlight, and the green color produced was not chlorophyll, but garlic green pigment.

2. Whether traditional garlic products, such as Laba garlic, sugar garlic, etc., or modern garlic products, such as garlic dry powder, garlic slices, garlic juice, garlic paste, garlic essential oil, etc., it is inevitable to face the problem of garlic greening during processing. If we want to control and reasonably apply garlic green pigment products, we must first understand the mechanism of garlic greening.

3. Through recent research, the research group found that the green pigment of "Laba garlic" is actually composed of a blue pigment produced by Mr. and a yellow pigment produced later. The transformation process of producing pigment is that allicin is produced first, and then it is transformed into allicin, and the production time of allicin is very short, that is, it is transformed into allicin. In the process of garlic processing, there are reports at home and abroad that garlic paste turns green, and the green pigment produced is not a common chlorophyll, which is the same as that in traditional Chinese food "Laba garlic".

4. According to the analysis of substance changes, sulfur-containing compounds such as thioaliphatic cysteine sulfoxide and thiopropenyl cysteine sulfoxide in garlic cells generate thiosulfinate, propenyl thiosulfinate and allyl thiosulfinate under the action of garlic enzyme, which are the precursors of garlic pigment substances, and further garlic turns green.

5. Low temperature is the condition to break the dormancy of garlic, activate alliinase and turn green. γ -glutamyl transpeptidase is essential in the process of pigment formation. The formation of "Laba garlic" green pigment is similar to onion reddening to some extent. When allyl and allyl sulfur oxides exist at the same time, it will turn green, propylene sulfur oxides exist, and when allyl sulfur oxides do not exist, it will turn red.

6. Alliinase plays a catalytic role in the greening of garlic. The acetic acid pickled "Laba garlic" can increase the permeability of cell membrane and make garlic turn green without destroying the cell wall.

Allyl and allyl cysteine sulfoxide become pigment intermediates under the catalysis of alliinase, which further react with basic amino acids with high content in garlic, such as lysine and arginine, to generate pigment precursors, and finally react with unsaturated compounds in garlic to generate garlic green pigment.

It was also found that the sulfur content of the pigment extract was significantly higher than that of the common garlic extract, indicating that the pigment was a kind of sulfur-containing non-chlorophyll compound, and the extracts of the two pigments of "Laba garlic" showed higher antioxidant activity than that of the common garlic extract. This suggests that the processing of "Laba garlic" not only optimizes the flavor, but also optimizes the functional activity.

7. The research group further studied the influence of processing conditions of "Laba garlic" on the green reaction. It was found that the stronger the activity of γ -glutamyl transpeptidase, the stronger the reaction of garlic greening. Garlic allicin thiosulfinate is the reaction substrate to produce green pigment. With the gradual increase of garlic green pigment, thiosulfinate gradually decreases. The formation of garlic pigment includes two reaction processes, namely enzymatic reaction process and non-enzymatic reaction process. Low pH value (2-4) is suitable for non-enzymatic reaction process, while high pH value (> 5) is suitable for enzymatic reaction process. Therefore, the ideal pH range should be the compromise between enzymatic reaction and non-enzymatic reaction, so the optimum acidity of garlic greening process is pH 5.

8. It was also found that the active function of the green garlic extract was better than that of the purified pigment, which suggested that the production of Laba garlic functional food might be more valuable than the processing of garlic green capsules in the further research and development of products. However, it is still necessary to analyze the composition and formation mechanism of allicin.

9. The research group plans to continue to explore the further purification and structural identification of the pigment and the isomerization of allyl cysteine sulfoxide and allyl cysteine sulfoxide in the following research.