Study on the storage and preservation technology o

Research on the storage and preservation technology of broccoli

Abstract starting from the experiments of temperature, packaging materials, preservatives and other aspects, it is proposed that the best temperature for storing broccoli is 0 ℃, packed in 0.04mm fresh-keeping bags, supplemented by thiabendazole smoke, and stored broccoli for 2 ~ 2.5 months; The weight loss is less than 1%, the flower ball is green, and the freshness of the incision is normal; The commodity rate is 95% - 99%

keywords broccoli; Temperature; packaging; Preservation; Preservative

the edible part of broccoli (Brassica oleracea trytis) is young pedicels and buds. After harvest, the buds breathe actively at room temperature, and are very easy to open, yellowing and the freshness decreases rapidly, which seriously affects the value of products. In 1995, the author first conducted a comparative experiment on the storage effect of broccoli at different temperatures, and studied the storage and fresh-keeping period of broccoli at different temperatures. The experiment shows that 0 ℃ can better maintain the appearance quality of broccoli and improve its merchantability after storage. In 1996, the author studied the packaging materials on the basis of selecting the appropriate temperature. The experiment showed that 0.04mm film bag packaging reduced the respiration of broccoli, reduced ethylene production, and met the gas conditions of broccoli during storage. With the extension of time, the propagation of various pathogenic bacteria causes some mildew spots on the flower ball. Fumigation with thiabendazole smoke can effectively inhibit the propagation of pathogenic bacteria and improve the fresh-keeping effect

1 materials and methods

the test materials were selected from the experimental field of our institute, and the Japanese variety xiashida (シャツタ) was used as the test materials. The harvest time is in the early morning. When harvesting, hold the flower ball with your left hand and cut it all at once to make the section smooth and minimize the damage of pedicel. The pedicel is generally about 14cm long and maintains 3-5 leaflets. After harvest, the flower ball dries the dew. First, the flower ball is dense, and the flower bud size is moderate. Enter the 0 ℃ storehouse directly for pre cooling for 24h, and then conduct the non pilot test. Measure relevant indicators respectively:

green ball rate determination: green ball rate = number of green balls/total number × 100%

determination of mold ball rate: mold ball rate = number of mold balls/total number × 1018. Net weight: 1900kg0%

determination of yellow bulb rate: Yellow bulb rate = number of yellow bulbs/total number × 100%

VC is determined by dichlorostarch method, and the gas composition is determined by Austrian gas analyzer

temperature treatment: i.e. 0 ℃, 5 ℃, 10 ℃, 15 ℃, 20 ℃ (without precooling at normal temperature). Each treatment of 15 flower balls is repeated for 3 times, and the concentration of CO2, O2, yellow flower rate, weight loss rate, chlorophyll and vitamin C are regularly measured

2 results and analysis

2.1 storage effect of broccoli at different temperatures

2.1.1 changes in storage appearance quality under different temperature conditions. See Table 1 for the results of the impact of different temperatures on the appearance quality of broccoli

Table 1 Comparison of appearance quality under different temperatures

storage period (d) temperature (℃) green ball rate (%), yellow flower rate (%) mold ball rate (%) The freshness of the incision is normal, 510000 normal, part moldy, all moldy, 510000 normal, part moldy, 20 - - normal, 510000 normal, 100100 - - all moldy, 15 - - 20 - - normal, 510000.7 part moldy, part moldy, part moldy, abnormal

it can be seen from table 1 that low temperature effectively inhibits the respiratory intensity of broccoli and slows down the decomposition of chlorophyll. The lower the temperature, the greater the inhibition, The more conducive to keeping fresh and green. Stored at 0 ℃ for 60 days, the flower balls remained green without yellowing and opening, and some of them had 1 ~ 2 small mildew spots, accounting for only about 4%; When stored at 5 ℃ for 45 days, the flower ball remained green, and some flower buds had mildew spots. At 60 days, 10% of them had yellowing, and the incision was abnormal; Stored at 10 ℃ for 7 days, 96% of the cyanated balls have decreased to 80% by 15 days, and the cut part has become moldy and lost its commodity value; When stored at 15 ℃ for 7 days, the blue and white balls were only 70%, and the incision was moldy and lost the commodity value; Stored at 20 ℃ for 2 days, it began to yellowing and lost its commodity value. The experiment shows that 0 ℃ can better maintain the appearance quality of broccoli and improve its merchantability after storage

2.1.2 changes of chlorophyll and vitamin C under different temperature conditions chlorophyll and vitamin C content are two important indicators to measure the fresh-keeping quality and nutritional value of broccoli. In terms of the total amount of chlorophyll in Table 2, there is almost no loss in its content when stored at 0 ℃ for 60 days, and the content is halved when stored at 5 ℃ for 45 days; However, 87% will be lost after only 15 days at 10 ℃, and chlorophyll a is mainly damaged. The original content of chlorophyll a is 1.5 times that of chlorophyll b, but it is less than half of chlorophyll b after 15 days. Vitamin C, stored at 0 ℃ for 45 days, its content loss was 18.3%; 58.4% were stored at 5 ℃. Storage at 0 ℃ for 60 days, loss 312, arc tooth synchronous reduction system 9%, while less than 50% remained after 15 days of storage at 10 ℃

Table 2 Changes of chlorophyll and vitamin C under different temperature conditions

storage period

(d) temperature

(℃) chlorophyll content (mg/100g) vitamin C

(mg/100g) chlorophyll a total chlorophyll b storage before storage 60.745.6106.3137.715104.59.313.836.545058.33896.3112.5 530.122.552.630.560059.833.593.393.6

2.1.3. Weight loss during storage at different temperatures is the most direct factor affecting the value of goods, Water loss not only affects the appearance of goods, but also directly affects the grade of goods. The test results show (Table 3) that the weight loss rate (7.6%) for 5 days at room temperature is very close to the weight loss rate (8.2%) for 60 days at low temperature. The former has an average weight loss of 1.9% per day, while the latter is only 0.137%

Table 3 Comparison of weight loss under different temperature conditions

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