Effects Of Three Preprocessing Methods On Cold Resistance Of Bitter Gourd

Bitter gourd is native to tropical and subtropical regions, it is prone to get yellow or red when store at room temperature, and vulnerable to chilling injury, so it is difficult to store and transport. In this experiment, hree cultivars of bitter gourd, Bixiu, Yonghua,2408 were chosen as experimental materials. The test used blank treatment, heat shock ?immersed with hot water of 42? for 5 min?, cold shock ?immersed with cold water of 0? for 0.5h, 1h, and 2h?, H₂O₂ ?0.001,0.01 and 0.1 mmol/L?, decompression soak for 80 s, then atmospheric pressure soak for 5 min, stored at 2?4 ?. By observeing sensory indicators ?chilling injury rate, chilling injury index, color-difference, firmness and moisture content?, physiological indexes ?conductivity, MDA content, CAT activity, POD activity, POD activity? and and the changes of H₂O₂ content. exploring the possible way to improve storage in bitter gourd cold resistance of optimum pretreatment and bitter gourd anti-regulation cold mechanism.The results showed that:?1? Cold storage directly after packaging is a simple way to storage the bitter gourd. The blank treated bitter gourd CAT activity, POD activity, SOD activity in cell was declined rapidly, H₂O₂ content rise promptly, and chilling injury symptoms appeared constantly, such as the firmness decreased, water loss, peel became yellow and red.?2? With low concentrations?0.01 and 0.001 mmol/L? H₂O₂ solution, a small amount of H₂O₂ molecules got into bitter gourd cells which could significantly increased the activity of antioxidant enzymes, slow fall color, firmness and mositure content, reduce chilling injury rate and chilling injury index, Treated with high concentrations of H₂O₂?0.1 mmol/L? solution, the bitter gourd conductivity and MDA levels were significantly higher than CK, and accelerate the antioxidant enzyme inactivation,bitter gourd cold-resistance is lowered when in low tempreture storage.?3? Heat shock treatment and cold shock 0.5 h treatment could effectively improve the bitter gourd CAT, POD, SOD activity, reduce H₂O₂ accumuluation reduce its chilling injury incidence and chilly index, slow its brightness, firmness and mositure content change, but heat shock treatment will accelerate the speed of bitter gourd from green to red; Cold shock 1 h and 2 h treatment, reduced the bitter gourd cold resistance.?4? The chilling injury and cell membranes between the degree of oxidation of the intracellular activity of antioxidant enzymes, H₂O₂ content were conductivity significantly correlated, and the interaction antioxidant enzymes also has a great influences on bitter gourd cold-resistance.