| Open-land produced Chrysanthemum nankingense was taken as experimental material to investigate the effect of storing temperature, packing method, application of phytic acid or fresh-keeping agent complex on the postharvest changes of quality, biochem-physiology of Chrysanthemum nankingense. The results were as follows:1. The effect of storage temperature and packaging method (openly packed or loosely closed packed) on the quality of Chrysanthemum nankingense during storage was investigated. The result showed that under 20℃for 5days, the weight loss of Chrysanthemum nankingense was 9.87% for openly packed and 3.37% for loosely closed packed, the etiolation ratio were 30.00% and 30.10% respectively, and the produce lost commodity value. Under 10℃for 15days, the weight loss of Chrysanthemum nankingense was 22.10% for openly packed and 3.20% for loosely closed packed, the etiolation ratio were 25.00% and 27.00%, respectively, and the produce also lost commodity value. When 0℃was used to store Chrysanthemum nankingense, there was almost no yellowing appeared even after 20 days, the weight loss was only 6.00% for openly packed and 0.40% for loosely closed packed. The average Vc and chlorophyll in loosely closed packed Chrysanthemum nankingense at 0℃for 20d were 2.33 times and 1.65 times compared to the contents in openly packed Chrysanthemum nankingense at 10℃for 20d. There was no chilling injury symptom observed in Chrysanthemum nankingense at 0℃for 20d, therefore 0℃was considered as the optimal storage temperature for Chrysanthemum nankingense.2. The effect of storage temperature and packaging method (openly packed or loosely closed packed) on the postharvest physiology of Chrysanthemum nankingense during storage was investigated. The respiratory rate at harvest was 129.80 CO2mg. Kg-1h-1, which is stonger than most leafy vegetables. The respiratory rate of Chrysanthemum nankingense during storage was smaller and changed more slowly at lower temperature, with the smallest at 0℃. After stored for 5 days at room temperature, the respiratory rate of openly packed and loosely closed packed Chrysanthemum nankingense were 243.10 CO2mg. Kg-1h-1 and 179.30 CO2mg. Kg-1h-1 respectively, which were 1.31 and 1.04 times of the respiratory rate at 10℃, and1.75 and 1.22 times at 0℃. The respiratory rate of loosely closed packed Chrysanthemum nankingense was smaller than that of openly packed ones stored for 10 and 20 days。O2.- content of Chrysanthemum nankingense at harvest was 8.87nmol. g-1. After stored for 5 days at room temperature, the O2.- content doubled (openly packed) even tripled (loosely closed packed). Lowering storage temperature would slow down O2.- increase, particularlt in loosely closed packed Chrysanthemum nankingense. O2.- contents of openly packed or loosely closed packed Chrysanthemum nankingense after 20 days storage at 10℃and 0℃were 32.21 nmol. g-1, 17.40 nmol. g-1, 13.35 nmol. g-1 and 10.92 nmol. g-1.The effect of storage temperature and packaging method (openly packed or loosely closed packed) on MDA of Chrysanthemum nankingense during storage showed the change partten as O2.-.The relative electric conductivity of Chrysanthemum nankingense during storage was increased. 0℃could reduce significantly the increase of relative electric conductivity in Chrysanthemum nankingense and there was no difference between two packages.POD in Chrysanthemum nankingense was 96.00 U. g-1 at harvest, and increased during storage. POD in Chrysanthemum nankingense after 20days at 10℃and0℃increased to 179.00 U.g-1 for openly packed and161.60 U. g-1 for loosely closed packed, and 148.80 U. g-1 for openly packed and 135.60 U. g-1 for loosely closed packed, respectively. There were significantly postive relationship between POD and O2.-(r=0.86943), POD and MDA (r=0.91733 )and POD and relative electric conductivity (r=0.92379).3. Chrysanthemum nankingense treated with different concentration of phytic acid showed that: Chrysanthemum nankingense treated with 0.10% phytic acid and stored at 10 for 12d had 19.55% yellowing ratio, 8.99% weight loss and 86.14% chlorophyll mainenance, compared to 29.15% yellowing ratio, 11.35% weight loss and 80.54% chlorophyll mainenance in Chrysanthemum nankingense treated with 0.05% phytic acid and stored under the same condition, much less than that of control. 0.50% phytic acid could cause burning symptom in Chrysanthemum nankingense slightly. The 0.10% phytic acid was the best concentration to keep Chrysanthemum nankingense fresh in reducing the loss of SS and protein, lowering respiratory rate, slowing down the formation of O2.- and MDA, maintaining higher activity of PPO and POD. The result also showed that the effect of phytic acid on Chrysanthemum nankingense appeared late. This effect was more obverious at later stage of storag.4. Orthogonal experiment was designed to investigated the effectiveness of fresh-keeping agents composed of 6-BA, GA, SA and OVI on Chrysanthemum nankingense. After stored for 12 days at 10℃and taking the maintenance of chlorophyall as considering index, all four factors of 6-BA, SA, GA and OVI were significangly effective to reduce etiolation of Chrysanthemum nankingense, and the importance from most effectiveness to lest was in the order of 6-BA, SA, OWI and then GA. The best combination of the four chemicals was 10ppm 6-BA + 20ppm GA + 14ppm SA + 100ppm OVI. The etiolation ratio, weight loss and chlorophyall maintenance of Chrysanthemum nankingense treated with the best combination and then stored at 10℃for 12d was 0, 4.90% and 98.77%. Chrysanthemum nankingense treated with the best combination could slow down losses of protein and S.S., could inhibit fiberization, could reduce the contents of O2.- and MDA, could keep. higher PPO and POD activities, and could postpone senescence.
|
PDF Full Text Request