| "Jindu I" Hainan red pitaya was used as the experimental sample to research the effects of different maturities when picking,heat treatment with different temperatures,UV treatment,1-MCP treatment,different ethyl alcohol treatment methods and clausena lansium essential oil treatment on the storage and preservation of the pitaya after being picked,to provide appropriate preservation technologies and theoretical reference basis for prolong the storage and preservation period of Hainan red pitaya.1.The effects of the maturity(70%,80%and 90%)of the pitaya on the storage quality after being picked were researched.The result indicated that the fruits with 70%and 80%maturity are able to retard the lowering of TSS content during storage;delay the lowering of superoxide dismutase(SOD)and peroxidase(POD)activity;and restrain the rising of malonaldehyde(MDA)content and lowering of anthocyanin content.Results demonstrated that the fruits with 90%maturity were with poor storage effect,and the fruits with 70%and 80%maturity were with relatively good storage effect.And at the same time,the quality indexes and flavor of the fruits with 80%maturity were superior to those of the fruits with 70%maturity.Therefore,80%maturity is the suitable storage maturity of the pitaya.2.The effects of treatment temperatures(45,50,55 and 60?)on the storage quality of pitaya after being picked were researched.The results indicated that,when the pitaya was stored for 12 days,the disease index of CK,45,50 and 55? was 53.33%,40%,26.33%and 33.33%,respectively.Compared with the control group,the difference was significant(P<0.05).The temperature of 60? in the treatment groups caused damage to the pitaya.Hot water treatment with the temperature of 50?is able to effectively prolong the falling of the disease index and weight loss ratio of the red pitaya,improve the growth of the total soluble solid(TSS)in the flesh,restrain the decline of SOD and POD activity,prolong the degradation velocity of anthocyanin contents and the decline of clearance rate(DPPH),and improve the preservation quality of pitaya.3.The effects of different UV exposure doses(6 kJ/m2,8 kJ/m2,10kJ/m2 and 12 kJ/m2)on the storage of the pitaya quality after being picked were researched.After the pitayas were stored for 12 days,and the MDA content of the pitayas with CK,6 kJ/m2,8 kJ/m2,10 kJ/m2 and 12 kJ/m2 UV treatment was respectively 46.68mmol/g,28.8mmol/g,19.92mmol/g,38.55mmol/g and 50.86mmol/g.The treatment of 10 kJ/m2 is significantly different from the control group(P<0.05).The results indicated that,10 kJ/m2 UV treatment is able to effectively prolong the decrease in TSS content of pitaya fruits,reduce the disease index and weight loss ratio,reduce the rising velocity of MDA content,maintain relatively high SOD and POD activity,and effectively keep the storage quality of the pitaya after being picked.4.The effects of different 1-MCP concentrations(0.75?l/L and 1.0?l/L)on the storage quality of pitaya after being picked were researched.The experimental research indicated that,with the delay of the storage time,different 1-MCP concentrations were able to prolong the storage and preservation period of pitaya and delay fruit senescence,especially,1-MCP with the concentration of 1.0?l/L had the best effect,it was able to significantly restrain the rising of pitaya weight loss ratio,delay the decline of TSS and anthocyanin.On the 12th day,the POD activity of the treatment groups and the control group was 3.13U/g.min,4.12U/g.min and 4.67U/g.min,respectively,compared with the control group,the treatment groups was with the growths of 1.01U/g.min and 1.34U/g.min,the treatment groups were significantly different compared with the control group(P<0.05).Therefore,1-MCP with the concentration of 1.0?l/L has good preservation effects for pitaya,it is able to effectively prolong the storage period.5.The effects of different ethyl alcohol treatment methods(soaking,spraying and fumigation)on the storage quality of the pitaya after being picked were researched.The result indicated that,different ethyl alcohol treatments had a certain preservation effect on the pitaya.During storage,compared with other treatment methods,soaking maintained the reduction of TSS and anthocyanin content of pitaya fruit to make SOD and POD activity be maintained in a relatively high level.On the 12th day,the weight loss ratio of control group and treatment groups was 14.5,5.98,6.76 and 8.57%,respectively,compared with the control group,the treatment groups were significantly different(P<0.05).Therefore,ethyl alcohol soaking treatment can effectively prolong the storage and preservation effects of pitaya.6.The effects of clausena lansium essential oil concentration on the storage quality and bacteriostatic effects of the pitaya were researched.In vivo experiment and vitro experiment have been carried out.The results indicated that in the vitro experiment,clausena lansium essential oil with different concentrations was able to restrain the pathogenic bacteria of pitaya fusarium.The bacteriostatic effect under the concentration of 2?l/mL had the best effects,the concentration of 2 ?l/mL effectively restrained the growth of the hypha of fusarium;The hyphostoma treated by 2 ?l/mL clausena lansium essential oil was sparse and with shortened and few branches,which indicated the antimicrobial mechanism of clausena lansium essential oil.In the in-vivo experiment,the disease index of 5?l/L,10?l/L,15?l/L,20?l/L and CK essential oil concentration on the 12the day was 36.33%?43.66%?30.3%?63.33%and 53.33%,respectively.It can be clearly seen that,the pitaya treated by the essential oil with the concentration of 15?/L,was with the lowest disease index,compared with the control group.The difference was statistically different compared with the control group.(P<0.05). |
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