| Garlic is a perennial herb of Allium Liliaceae. After dormancy, garlic passed dormant period and bulbil germ began to grow. The metabolic activity of garlic is intensified, lead to the increase of nutrient consumption, which seriously affects the edible, medicinal value and processing quality of garlic bulb. Taking Xinjiang Jimsar red garlic as material, using controlled atmosphere storage(O2 concentration was 3.5%, the respectively CO2 concentration was 5%,8%,11%,14%), modified atmosphere(MA), room temperature storage (RT) and cold bulk storage (CK) to study the characteristics of different storage methods on garlic bulb storage and the influence of the quality change. In order to standardize the garlic spicy content determination method, and has set up a determination method in the experiment.Some conclusions have been drew:(1) Determine the pyruvic acid content in garlic bulb after the enzymatic reaction. The pyruvic acid content in garlic bulb with enzyme killing group as the background, the pyruvic acid content in garlic bulb was calculated by pyruvic acid dispersion method. And the determining conditions were optimized. The results show that the enzyme killing should be done in boiling water bath for 30 minutes. The best temperature and time of enzymatic reaction are 30℃ and 10 minutes. Pyruvic acid content detected at 520 run was 10-50μg/mL and showed a good linearity relationship with absorbance values.(2) Low temperature conditions can effectively inhibit the garlic in the storage process of weightlessness rate, bud disc ratio, water content, bulbil colour and lustre and the change of hardness. The ratio of different gases significantly affected the rot rate. Under the conditions of room temperature treatment in 30 days, the weight loss rate of garlic bulb was as high as 35%, and the weight loss rate under the condition of cold storage was less than 4.6%; at room temperature in 60 days, the dormancy period of garlic was over, and the inner bud started germination.When 150 days the shoots disc ratio is 88.71%, and cold storage control group was 32.58%, the controlled atmosphere storage group had no germination; In room temperature treatment group, the L value and b value of the skin color of garlic were 70.46 and 64.55 initially, and decrease to 64.55 and 31.11 respectively. The hardness of garlic increased from 1677N to 3122N, and the change varied significantly. Low temperature is conducive to the reduction of the rate of decay, but the rate of MA treatment is as high as 26.30%, second only to RT treatment 34.69%, the lowest rate of decomposition is controlled atmosphere storage treatment reached 12.77%. (3) The quality of garlic bulb was monitored during 150 days of storage. Determine the total soluble sugar, reducing sugar, soluble protein, free amino acid, VC, titratable acid, allicin and other indicators. Under RT processing, the bulbil of garlic germinated, leading to rapid depletion of nutrients and quality deterioration. And low temperature condition can effectively slow down the changes in soluble protein, free amino acids, titratable acid and allicin content. MA treatment and controlled atmosphere storage treatment 3,4 promote the soluble sugar, reducing sugar and titratable acid changes. Controlled atmosphere storage control the increase of allicin content by controlling alliin enzyme activity. Allicin content of treatment 4 reaches minimum after 90 days, as 7.46mg/g. Other treatments reach minimum after 120 days, and controlled atmosphere storage treatments is lower.(4) In the process of storage, the overall trend of the enzyme activities in the antioxidant enzyme system of garlic was increased. The peroxidase (POD), catalase (CAT), superoxide dismutase (SOD) showed a sustained rise, RT treatment were at the highest level, and the first to reach the peak of enzyme activity; The enzyme activities of controlled atmosphere storage treatment 2,3 were low; The activity of ascorbic acid peroxidase (APX) of ck treatment was highest, reached 378.35U.The phenylalanine ammonia lyase (PAL) activity of RT treatment was the highest, reached 535.91U.The activity of the enzyme was stable under cold storage condition. The content of malondialdehyde (MDA) of controlled atmosphere storage treatment 3,4 was highest, reached 0.0384、0.0299μmol·g-1 respectively.(5) In 7 kinds of storage conditions, by combination of controlled atmosphere storage at low temperature (O23.5%+CO25%+N291.5%) effect is good. It can keep the storage properties of garlic bulbs, and maintain the good storage quality. This method can keep the storage characteristics and good quality of garlic bulb. Preliminary selected as the optimal parameters of controlled atmosphere storage at low temperature of garlic. |
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