Studies On Effect Of Different Storage And Cooking Methods On Quality Of Broccoli

Broccoli (Brassica oleracea L. var. italica) is popular with many customers because it is high in vitamin C and anticancer glucosinolates. The quality of broccoli, including visual quality, nutrient quality and healthy quality, is essential to its price and market competition. Currently, researches on post-harvest technology of broccoli mainly focus on visual quality and nutrient quality, and few studies on its healthy quality are reported. In the study, we tend to evaluate a post-harvest technology by investigating the changes in nutrient and healthy quality of broccoli besides the visual quality under the post-harvest handling, and the effects of different post-harvest storages and cooking methods on the quality of broccoli were studied. The results were as follows:1) Broccoli florets were treated with 1-MCP at 2.5 μl/L for 6 h at 20℃, and the results showed that 1-MCP treatment was effective in extending the storage life, delaying the yellowing and weight loss, inhibiting the degradation of chlorophyll Vitamin C, carotenoid and anticancer glucosinolates, increasing the activity of antioxidant enzymes. As high temperatures are often encountered during the handling, transportation and retail marketing of broccoli, it has become the main cause of postharvest loss of broccoli, especially in developing countries. In our study, the use of 1-MCP could reduce the requirement for low temperature while still extending the storage life and maintain the quality of broccoli duiring storage at relatively higher temperature, and therefore is potential in post-harvest handling of broccoli.2) The effect of modified atmosphere packaging (MAP) on quality of broccoli was studied. The films used in our test were 0.02 mm PE, 0.04 mm PE and 0.06 mm PP respectively. The broccoli heads were stored at 20℃ and 4℃ respectively. The results showed that MAP could maintain the visual quality of the broccoli heads, and the broccoli packaged with 0.04 mm PE film were inbetter visual quality than those packaged with 0.02 mm PE and 0.06 mm PP. We future studied the effects of low temperature and different packaging designs (MAP with macroholes> microholes and no noles) on the quality of broccoli. The result showed that MAP in low temperature could regulate spontaneously the concentration of CO2 and O2, delay the yellowing and weight loss, inhibit the degradation of nutrient components and glucosinolates, and effectively postpone the senescence of broccoli. The best method was storage of broccoli in MAP with no holes and refrigeration at 4°C. 3) The effect of different cooking methods on the quality of broccoli was studied. Boiling, steaming, microwaving, frying and braising were the five domestic cooking processes which were used in this work. Great changes on the content of chlorophylk Vitamin C-. carotenoid and glucosinolates in broccoli were observed during cooking. Among the five cooking methods, steaming is the best method to maintain the nutrient and healthy quality of broccoli.