Application of Garlic Extract in Preservation of Fruit and Vegetables

Garlic is a perennial perennial herb of Liliaceae, which has both nutritional value and an indispensable seasoning in people's daily life. Garlic has a strong antibacterial ability to a variety of bacteria and fungi, and has an inhibitory effect on the growth and reproduction of microorganisms. Using its antibacterial properties to keep fruits and vegetables fresh, it is safe and non-toxic, and does not affect the original quality of fruits and vegetables.

The preservation mechanism of garlic extract:

The mechanism of garlic extract fresh-keeping fruits and vegetables is mainly related to its anti-disease and bactericidal properties.

Studies have shown that allicin is one of the main active components of fresh garlic, and has a broad antibacterial spectrum. It has a strong inhibitory effect and also has toxic effects on human intestinal parasites such as intestinal lambs. The antibacterial mechanism of allicin is that it can chemically react with the sulfhydryl group of sulfhydryl enzymes, such as alcohol dehydrogenase, thioredoxin reductase, etc., thereby affecting the activity of cysteine protease and inhibiting metabolism. In addition, allicin inhibits cell growth and induces apoptosis, which can lead to depolarization of the mitochondrial membrane, release of cytochrome C into the cytoplasm, activation of caspase 9 and caspase 3, resulting in DNA cleavage. Domestic research believes that it may be due to allicin and its further decomposition product ajoene, disulfide, trisulfide and other components in garlic oil can penetrate the cell membrane of pathogenic bacteria and enter the cytoplasm and interact with cysteine. The reaction makes the bacteria unable to carry out biological oxidation due to the lack of cysteine, so the pathogenic bacteria cannot carry out normal metabolism; allicin also inhibits the activity of sulfhydrylase on which the growth and reproduction of microorganisms depend, so that the growth of bacteria cannot reach the desired effect. The number of growth period, so as to play a role in inhibiting or killing bacteria. The researchers also found that garlic polysaccharide also has a certain antibacterial effect, but its mechanism has not been reported.

Application in fruit preservation:

Studies have shown that when the concentration of garlic essential oil is 20 μL/L, it has a significant inhibitory effect on the rot of postharvest apricot fruits, and the good fruit rate is increased by 60% compared with the control. The researchers used red orange as raw material, added or not added 8 concentrations of chitosan to form 8 treatments of the coating liquid, and studied the effect of different ratios of chitosan and ginger garlic extract at room temperature. Preservation effect of compound coating liquid on red orange fruit. The results showed that fresh ginger and garlic were used as materials, and the ratio of fresh weight (g) to solvent (mL) was 1:60, and the extract was extracted with 40% ethanol to obtain an extract. The extract was used as a solvent to prepare a concentration of 1.0% glacial acetic acid solution, then use 1.0% glacial acetic acid solution as solvent, prepare 1.5% concentration chitosan solution as coating solution, soak for 1min, the fresh-keeping effect of red orange fruit is the best, when stored for 50 days, its fruit The rot rate was the lowest at 5.9%, and the total acid content and vitamin C content of the fruit changed the least.

Using distilled water as a control, the fresh-keeping effect of garlic extract on nectarine fruit was studied. The results showed that garlic extract with different solid-liquid ratios could inhibit the respiration intensity, rot index and relative conductivity of nectarine during storage, delay fruit firmness, Decrease in vitamin C, titratable acid and soluble solids content extends the shelf life of nectarines. The rot index of the nectarines treated with the control treatment reached more than 43% when stored on the 9th day; the rot index of the nectarines treated with the garlic extract with a solid-liquid ratio of 1:10 was only 32.6% when stored on the 12th day. Han Hongyan et al. took winter jujube fruit as material, treated winter jujube with fresh garlic juice (0.3%, 0.5%) of different mass fractions, stored at 0 °C, and measured the quality index. The results showed that garlic juice treatment significantly improved the fruit's flavor and color. , Improve the sensory quality of fruit, reduce the redness index and rot rate, inhibit the loss of vitamin C content, and prolong the shelf life of winter jujube. The combination of low temperature (0~2℃) and garlic juice (0.5%) treatment has good storage effect and can Finish normal after-cooking.

Using black grape as material, the effects of chitosan single coating and chitosan and allicin composite coating on the fresh-keeping effect of black grape were studied. Reduce weight loss rate and accumulation of malondialdehyde, delay degradation of soluble solids and titratable acids, improve fruit yield and fruit stress tolerance, maintain high activity of superoxide dismutase, in contrast, allicin and chitosan The fresh-keeping effect of sugar-compounded edible film was significantly better than that of single chitosan treatment.

The researchers compounded garlic and ginger extracts and used sodium benzoate as a control to determine the antibacterial effect on indicator bacteria. The results showed that the antibacterial effect of the compound extract (volume ratio 1:1) was better than that of sodium benzoate; Thermal determination showed that the antibacterial components of the compound extract were not stable to high temperature, and through further observation on the preservation of fruits and vegetables, the shelf life could be extended after soaking in the compound extract. Strawberry and bayberry were treated with different concentrations of raw garlic and cooked garlic extracts, respectively, and the rot rate, weight loss rate, vitamin C change rate and sensory quality of strawberry on the 5th day were detected within 11 days. The results showed that the extracts of raw and cooked garlic with different concentrations had a certain preservation effect on strawberry and bayberry. Taking into account comprehensively, the fresh-keeping effect of strawberry and bayberry is best with the extract of cooked garlic with a concentration of 10%. The researchers used the compound solution of garlic, chitosan and lychee peel to study the fresh-keeping effect of citrus, from the weight loss rate, malondialdehyde content, superoxide dismutase content, vitamin C content, titratable acid content and mildew of citrus From a comprehensive view of the six measurement indicators of variability, a solution composed of 2% chitosan was added to the garlic alcohol extract with a solid-to-liquid ratio of garlic and 30% ethanol of 2:1. The solution composed of adding 1.5% chitosan to the alcohol extract with the ratio of extracts at 2:1 has a significant effect on citrus bacteriostasis and preservation.

Application in vegetable preservation:

The study found that garlic and its extracts have fresh-keeping effect on vegetables, and the fresh-keeping effect of ethanolic garlic extract is better. The researchers studied the storage effects of garlic preservatives and burial treatments on yam. Weight loss rate, vitamin C content, respiration intensity, peroxidase (SOD) activity, malondialdehyde content, and decay rate were determined in the experiment. The results show that burial can effectively delay the aging of yam, and garlic preservative can effectively reduce the decay. The combination of the two is an ideal way to store and preserve yam. The study found that when the ratio of fresh weight (g) of ginger and garlic to solvent (mL) was 1:60, the extract mixture of ginger and garlic anhydrous ethanol had the best fresh-keeping effect on vegetables.

Using shiitake mushroom as raw material, the fresh-keeping effect of different concentrations of garlic extract on shiitake mushroom was studied. The results showed that different concentrations of garlic extract can inhibit the respiration intensity, weight loss rate, cell membrane permeability and decay index of Lentinus edodes, reduce the changes of appearance and quality of Lentinus edodes, and effectively delay the aging and decay of Lentinus edodes. The effect of different concentrations of garlic extract on the preservation of shiitake mushrooms is in descending order: solid-liquid ratio (g:mL) 1:5>solid-liquid ratio (g:mL) 1:10>solid-liquid ratio (g:mL) 1:15> solid-liquid ratio (g:mL) 1:20. The effect of chitosan ginger garlic extract compound preservative on the quality of chicken leg mushroom during storage and preservation was studied by orthogonal experimental design. Through the determination of 10 physical, chemical and sensory indicators, it was confirmed that the compound preservative can effectively prolong the storage period of chicken leg mushroom. , the preservation effect was significant (p<0.05), and the optimal ratio was 1.5% chitosan, 20% garlic juice, and 10% ginger juice.

At present, there are few studies on the mechanism of antibacterial and antioxidant effects of garlic extract. Strengthening the research on these mechanisms will help the promotion and application of garlic extract in the field of food preservation. With the improvement of people's living standards, people pay more and more attention to the naturalness and safety of food, and the research on fruit and vegetable preservatives is also developing in a natural, safe and effective direction. Therefore, garlic extract is a green, natural Food preservatives will have broader application prospects.