Native to Western and Central Asia, garlic has a history of more than 2,000 years since The Han Dynasty, when Zhang Qian brought it back to China on a diplomatic mission to the Western Regions.China now produces more than 70 per cent of the world’s garlic.According to the color of the bulb, garlic can be divided into purple garlic and white garlic.Purple garlic cloves less and large, spicy strong;There are two kinds of white garlic, big and small, spicy taste is lighter.This study intends to discuss the chemical composition of garlic, the preparation method of garlic extract and its application in food processing, in order to provide reference for the development and utilization of garlic and its extract.
Garlic extract refers to the crude extract extracted from garlic after mashed with organic solvent or water.The main extract of garlic is allicin, and its main component is diallyl thioether. It is an extremely unstable organic sulfide, which is almost completely decomposed at room temperature (20 ℃) after 20 hours, and the decomposition rate is accelerated after being heated.Therefore, it is difficult to extract and preserve allicin, which is one of the important components in allicin extract with antimicrobial effect.
Application in food preservation
Garlic has the disinfection sterilization, enhances the immunity function.Chen Hongsheng et al. applied the antioxidant capacity of garlic to the preservation process of chilled meat, and determined the preservation and antioxidant effects of different concentrations of garlic extract on cooled meat by measuring its microbial indexes and physical and chemical indexes and combining with sensory evaluation.The results showed that when the concentration of garlic extract was 2%, it had better antibacterial and antioxidant effects on the chilled meat, and had little effect on the color of the meat.Li Tingting et al. studied the effect of garlic extract on the quality of frozen vegetable fish balls. The experiment was to add garlic extract of different mass concentrations to vegetable fish balls and compare the changes of indexes (sensory indexes, microbial indexes, chemical indexes, etc.) in each experimental group under the refrigerated condition of 4 ℃.The results showed that the fresh effect of garlic extract was the best at 200 mg/kg, and the shelf life of fish balls could be extended for 7 ~ 8 days.After comparing the total number of bacteria, pH value, TBA, TVB-N and other quality indexes, we know that garlic extract can effectively inhibit the growth of bacteria and slow down the oxidative deterioration of protein and fat in the process of fish ball preservation in cold storage.Zhao Mei mushroom as raw material, such as different concentrations of garlic extract was studied in mushroom fresh-keeping effect, the results showed that different concentrations of garlic extract can effectively inhibit the respiration intensity of xianggu mushroom, cell membrane permeability, the weightlessness rate and decay index, also can reduce the change of the mushroom and appearance quality, delay the mushroom and corruption, which is expected to liquid ratio (g/mL) for 1, 5 of garlic extract has the best effect of mushroom fresh.
Garlic extract not only has antibacterial and antiseptic effect, but also can regulate physiological metabolism of fruits and vegetables and keep good quality of fruits and vegetables.Feng Deming et al. applied allicin alcohol extract to the preservation of soybean products and achieved good results.
Form a unique aroma
The study found that: garlic at 150 ~ 160 ℃ after heated by oil, sulfur ether compounds can form a special taste and aroma, garlic broccoli, garlic spare ribs, garlic fish and shrimp cooking is to take advantage of this feature.Gao Xueqin et al. measured the influence of different cooking methods on allicin by the method of fixed sulfur, and the results showed that the most suitable cooking method for garlic was microwave heating, and the most destructive method for allicin was frying cooking.“Garlic burst” cooking method, is in high oil temperature under the rapid heating garlic, make it produce fragrance, this method in the cooking of leaf vegetables, stem vegetables often used, such as garlic lettuce, garlic amaranth, garlic Fried rape and so on.The combination of allicin and vegetables gives a different flavor to dishes.
Bactericidal and disinfecting effect in cold dishes
Allicin contained in garlic and the thioether in the active ingredients, such as ahorene and garlic oil, can effectively inhibit the activity of polymerase or metabolism of lipids through the reaction with cysteine, and play an inhibitory or killing effect on a variety of pathogenic fungi and bacteria.Allicin and allicin, the antibacterial components in garlic, have strong bactericidal effect on pathogenic intestinal bacteria such as Dysentery bacillus and typhoid bacillus, so it is widely used in the production of cold dishes. However, in the process of use, the amount of garlic should be based on the premise that it does not damage the flavor of food and the original taste of food.