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Research On Effects Of Cold Storage Conditions And Vibration Stress On Post-Harvest Storage Quality Of Hayward Kiwi Fruit

Posted on:2019-05-10Degree:MasterType:Thesis
Country:ChinaCandidate:Q WuFull Text:PDF
GTID:2381330566974585Subject:Power Engineering
Abstract/Summary:PDF Full Text Request
Kiwifruit?scientific name:Actinidia chinensis Planch?,also known as kiwifruit,is a low-calorie,high-vitamin C fruit that is sweet,sour,and nutritious and has a highnutritional and health value.Actinidia chinensis Planch Hayward is a series of delicious kiwifruit.It is one of the main cultivars of Chinese kiwifruit.Its greatest feature is its fruit-type beauty,excellent quality,and good yield.However,kiwifruit is a kind ofberry-like respiration-changing fruit.The juice is thin and has a large respiratoryintensity at room temperature,which is easy to soften and rot,and has a short storage time.Cold storage is a method of preservation of preserved foods at refrigeratedtemperatures?often above the freezing point?,mainly to make their life metabolism as slow as possible,to maintain their freshness,especially for the collection of fruits and vegetables,is the most effective way to preserve freshness.one.However,not all fruits and vegetables can be extended shelf life under refrigeration conditions,cold sensitive fruit is very sensitive to low temperatures?usually below 10C20C?,such as some tropical and subtropical fruits and some vegetables if their freezing point above When stored at 310C,cold injury will occur,which will affect the storage quality of fruits and vegetables,destroy the normal physiological metabolism of fruits and vegetables,and cause internal cell membrane structural damage.The occurrence of chilling injury depends not only on the storage temperature and the duration of low temperature,but also on the adaptation and resistance of cold-sensitive fruits and vegetables to lowtemperatures.Researchers at home and abroad have conducted extensive research on the mechanism of cold damage of fruits and vegetables,but no conclusions have been reached yet.Therefore,it is of great theoretical and practical significance to explore the storage mechanism of kiwi fruit under refrigeration conditions to find out the optimal storage conditions and control methods.Vibratory stress is the stressing action of the machinery on the objects it carries during the operation of the vibration,so that the objects undergo some degree ofchange.The role of vibration stress often occurs in the process of long-distance transportation of fruits and vegetables from the planting place to the sales place,especially various road transport.Vibration stress involves many aspects such as the physical characteristics of fruits,ripening and aging mechanisms,resistancemechanisms,and so on,so the impact of vibration stress in the fruit transport process can not be ignored.In addition,since kiwifruit is a respiratory-climbing fruit,it is often necessary to pick up the shelf-life of the product if it is not fully matured.If vibrational stress can be used to ripen the fruit,we can control its maturation time and maturity to better Eat kiwifruit.Therefore,the study of the influence of vibration stress on thepostharvest physiology and quality of fruit is also of great practical value and practical significance for establishing fruit preservation,transportation and marketing systems.This article takes a typical after-ripening fruit kiwi fruit as the research object,the variety is"Hayward".Set 0C,4C,and 8C as refrigerating conditions for cold storage.Kiwi fruit was stored in three types of refrigerated storage at a frequency of 3 Hz,amplitude of 5 mm,and shaking time of 10 hours.For the refrigeration group.Inaddition,the 0h,10h,and 20h vibration durations were set,the vibration frequency was3 Hz,and the vibration amplitude was 5 mm.The kiwifruit was subjected to vibration treatment and stored in a cold storage at 4C in a refrigerated condition.The vibration group was named.The changes of tissue structure,quality,physiological andbiochemical characteristics,active oxygen metabolism,membrane lipid oxidation,antioxidant system and related enzyme activities of fruit cells under the same storage temperature and different vibration treatment at different storage temperatures were measured.From the perspective of the changes of cell membrane permeability caused by the damage of cell membrane,combined with changes in the electrolyte leakage rate,the hypothermic temperature of kiwifruit was inferred to be the optimal storagetemperature for kiwi fruit,and the mechanism of vibration stress on kiwi fruit qualitywas explored.To reduce and prevent the chilling damage of kiwi fruit and to reduce and control the damage caused by vibration stress on the fruit quality of kiwifruit provides theoretical and experimental evidence.The main contents and results of this study are as follows:1.The effects of different refrigerated conditions on the quality index of Hayward kiwi fruit during storage were studied.The physiology of respiration rate,ethylene metabolism,weightlessness rate,soluble solids and fruit firmness were compared during the storage period?28 days?of Hayward kiwifruit stored under 0C,4C and 8C refrigerated conditions after 10h of vibration stress.Biochemical quality changes,electrical conductivity,lipoxygenase?LOX?,malondialdehyde?MDA?,reactive oxygen species?ROS?changes,and VC,ascorbate peroxidase?APX?,superoxide dismutase?SOD?,catalase?CAT?and changes in antioxidant system and related enzyme activities.The results showed that duringstorage,kiwifruit respiration ethylene was significantly inhibited and the rate of weight loss increased,the soluble solids content increased,and the hardness decreased,butthese changes were smaller at 8C than at 0C and 4C.,indicating that refrigerated slows the respiratory maturation mechanism of kiwifruit.After 28 days of storage,the electrical conductivity of kiwifruit stored at 0C was significantly lower than 4C and8C.The content of MDA also increased continuously and the slowest growth wasobserved at 0C.The peak value of lipoxygenase peak at 0C was the lowest.Oxygen production was also significantly inhibited,with 0C being more effective than 4C and8C in inhibiting cell membrane changes in Kiwifruit?P<0.05?.After storage for 28days,the four indexes of antioxidant system in kiwifruit fruits at different refrigerated temperatures were lower than 4C and 8C at 0C,indicating that low temperature will delay the enzymes in the antioxidant protection system of kiwifruit during storage and The decrease in the activity of antioxidants.It shows that the refrigerated temperature will affect the membrane lipid oxidation during the storage of the melon,and theappropriate refrigeration temperature will delay the destruction of the cell membrane integrity,and ultimately delay the ripening and aging of the kiwifruit.2.The change mechanism of storage quality index of Hayward kiwi fruit after storage under refrigeration temperature was studied.In the storage environment of refrigerated temperature at 4C,the physiology of respiration rate,ethylene metabolism,weightlessness rate,soluble solids and fruitfirmness during the storage period?28d?of the kiwifruit kiwifruit treated with 0h,10h and 20h vibration stress were compared.Biochemical quality changes,electricalconductivity,lipoxygenase?LOX?,malondialdehyde?MDA?,reactive oxygen species?ROS?changes,and VC,ascorbate peroxidase?APX?,superoxide dismutase?SOD?,catalase?CAT?and changes in antioxidant system and related enzyme activities.The results showed that during the cold storage period,the physiological activities ofkiwifruit,such as respiratory ethylene,were obviously active,the weight loss rate increased,the soluble solids content increased,the hardness decreased,and the fruitmetabolism after 20 h vibration was significantly higher than 10 h and not.The obvious vibration indicates that the vibration stress promotes the ripening and aging of kiwifruit.After 28 days of storage,the electrical conductivity of kiwifruit after vibration for 20h was significantly higher than 10h and without vibration,and the content of MDAincreased continuously and the increase of 20h was fastest.The peak of lipoxygenase activity at 20h was the highest and the earliest decline was observed.However,the production of reactive oxygen species was also more pronounced,and the promotion of cell membrane destruction of kiwifruit was more significant at 20h than at 0h and 10h?P<0.05?.After 28 days of storage,the four antioxidant system and related enzymeactivity indexes of kiwifruit treated with 10h and 20h vibration stress were lower than those without vibration,and the antioxidant system of kiwifruit was treated with 20h and 10h vibration stress.The damage was even more pronounced?P<0.05?,indicating that the vibration will promote the respiratory ethylene metabolism during storage of kiwifruit and reduce the activity of various enzymes and antioxidants in the antioxidant protection system,thereby accelerating the oxidation of cell membrane lipids anddestroying the integrity of the cell membrane.Accelerate the aging and corruption of kiwifruit.This article comprehensively studied the fruit shape,hardness,weight loss rate,respiratory ethylene release rate,soluble solids content,O2-production rate,H2O2content,LOX activity of Hayovat kiwifruit after typical temperature and vibration stress treatment.Changes in parameters such as MDA content,relative electrical conductivity,Vc content,SOD,CAT,APX and other membrane lipid protective enzyme activities,and the analysis of the interrelationships between the quality indicators of each storage and the impact mechanism are post-harvest Hayward kiwi fruits.The theoretical basis and application reference for finding the optimum temperature for storage andpreservation are provided,and the data foundation and possibility for controlling the fruit ripening degree of kiwifruit through moderate vibration stress treatment can be provided.
Keywords/Search Tags:Kiwi, cold storage, vibration stress, physiological and biochemical characteristics, ROS, antioxidant system
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