Study On Mechanism Of Energy Loss On Quality Deterioration Of Vitis Vinifera L.Grape Fruit During Storage

To investigate energy metabolism of harvested grape fruit during quality deterioration,"Red Globe" and "Victoria" grapes were dipped into solutions of chitosan coating with calcium,calcium with citric acid water,calcium with hot water or ClO2 solution as test materials.Then fruit were stored for 42 days at(4 ±0.5)?.Characteristics of fruit quality,texture properties,physiological characteristics,nutrients,ultra-structure,cell wall compositions and cell wall metabolism,energy levels and energy metabolism,et al.were studied.This paper found that aging and quality deterioration of grape fruit associated with energy metabolism and energy levels.Maintaining grapes quality and prolonging fruit freshness would be realized through regulating energy state.The main results were as follows:(1)Texture is an important indicator of fresh fruit quality.To study texture changes of Vitis Vinifera Grape during storage after different post-harvest treatment,five different post-harvest treatments were applied on Red Globe and Victoria grapes.Resuts showed that hardness,gumminess,elasticity and fracture resistance were good positive correlation(R=0.94?1.00,P<0.01),and negatively correlated with cohesion(R =-0.72?-0.71,P<0.05).Fracture resistance,elasticity,gumminess and chewiness were good positive correlation(R=0.85?1.00,P<0.01).Elasticity and gumminess were positive correlation with chewiness(R = 0.96?0.97,P<0.01).Gumminess and chewiness were significant positive correlation(R =0.95?0.94,P<0.01).Hardness and gumminess were positively correlated with chewiness(R = 0.85?1.00,P<0.01).Hardness,gumminess and chewiness were applied to compare texture change parameters.Different post-harvest treatments showed overall downward trend,but different post-harvest treatments showed different downward trend while antimicrobial preservative treatment declined most obviously.Test proved post-harvest treatment technology was an important factor affecting texture during storage.Different post-harvest treatment changed texture of grape,increased firmness,gumminess and chewiness.(2)From sensory,inner quality,energy levels and contents of antioxidants in cell tissue of "Victoria" and "Red Globe" grape fruits,differences of quality deterioration and energy loss were studied between "Victoria" and "Red Globe" grape fruits during storage.Results showed that decay rate,membrane permeability and MDA contents of"Red Globe" grape were lower than "Victoria",but energy levels,contents of anthocyanins,flavonoids,tannins and total phenol were higher than "Victoria".ATP contents were positive related with hardness(R=0.98,P<0.01),but negative related with membrane permeability and MDA(R=-0.86,-0.86,P<0.01).Endogenous antioxidants contents were negative correlation with MDA(R=-0.77,-0.76,-0.77,-0.71,P<0.05).Energy levels and endogenous antioxidants had direct effects on fruit quality deterioration.During storage,"Red Globe" grape fruit had better quality than"Victoria" at late storage time.(3)Effects of energy status on nutrition quality deterioration in grape fruit tissues during cold storage were studied.Energy levels in grape fruit tissue were in a loss state with extension of storage time.Energy substances were decreased,such as ATP,ADP,AMP and main nutrition attributes(e.g.,SSC,TA,Vc,organic acids and soluble sugars),while only pH values were increased.Appropriate post-harvest treatments alleviated energy losses and delayed quality deterioration,especially coating treatment.ATP levels showed quadratic equation fitting curve with contents of Vc and TA,fitting degrees more than or close to 0.9.There were good linear equation fitting curves between SSC,glucose,tartaric acid and pH value with ATP content,and fitting degrees close to 0.9.ATP contents were significantly positive correlated with tartaric acid,SSC,VC TA and glucose(R=0.90-0.94,P<0.01),but significantly negative correlated with pH(R=-0.93,P<0.01)in correlation analyses.Energy levels have direct effects on qualities deteriorations of grape fruits.Ways of keeping high energy levels of grape fruits can maintain good quality of grape fruits.(4)Effects of coating and heat treatments on energy levels and physiological deterioration of post-harvest "Victoria" grape fruit during cold storage were explored through determining energy levels and physiological indexes.Results showed energy levels were in a loss state in CK grape fruit tissue with extension of storage time.Respiratory decreased,but cell membrane oxidation and permeability increased.Browning index and decay rate increased,enzyme activities of POD,PPO and LOX increased too,but enzyme activities of SOD were decreased.Physiological qualities of grape fruits decreased,and fruit softening.Heat and coating treatment reduced loss of grape fruits for rotting during storage.In addition,treatments of heat and coating could maintain higher energy status,energy charge,hardness,enzyme activities of SOD to keep qualities of grape fruit,and delay grape fruit softening,inhibit respiratory intensity,inhibit accumulation of membrane lipid peroxidation,slow down growth of cell membrane permeability,decrease MDA content,inhibit enzyme activities of POD,PPO and LOX,delay browning and rotting,delay aging process of grape fruits and physiological quality deterioration.But coating treatment was better than heat treatment.ATP was significant positive correlation with hardness and SOD enzyme activity(R = 0.94,0.93,P<0.01),but negative correlation with MDA membrane permeability and LOX enzyme activity(R =-0.90,-0.93,-0.94,P<0.01).EC was negative correlation with membrane permeability and LOX enzyme activity(P<0.05),but positive correlation with respiration intensity and SOD enzyme activity(P<0.05).Browning of grape fruits were closely related to membrane lipid peroxidation and membrane structure.Integrity of membrane structure destroyed.PPO and POD were reacted with phenolic substrates to form brown pigment.With extension of storage time,energy levels of grape fruits were in a loss state.Fall of energy level was significantly affected oxidation and integrity of cell membrane.Coating and heat treatments could maintain higher energy levels of ATP,ADP and EC,which could slow down aging and physiological quality deterioration of grape fruit tissues.Coating and heat treatments may maintain high energy status and physiological qualities,slow down aging and physiological quality deterioration of grape fruits tissues.Effects of coating treatment were better than heat treatment.Slowing down physiological deterioration of grape fruits can be realized by maintaining high energy status and preventing development of physiological deterioration.(5)Effects of coating and heat treatment on aril breakdown of "Red globe" grape fruit and its relation to energy metabolism were investigated in this study.Membrane integrity,energy levels,activities of metabolism-related enzymes were decreased,but after coating and heat treatment maintained higher than those of CK.In reducing aril breakdown index,maintaining membrane integrity and ATP level,coating treatment was significantly better than heat treatment(P<0.05).Aril breakdown indexes were extremely significant positive correlations(R = 0.73,0.79,P<0.01)with membrane permeability and MDA contents,but negative(R =-0.79?-0.54,P<0.01)with energy levels and energy charge.Aril breakdown indexes were extremely significant negative correlations(R =-0.75--0.70,P<0.01)with mitochondrial protein contents and activities of metabolism enzymes.Aril breakdown indexes were close relations with changes of membrane integrity and activities of energy metabolism.Coating and heat treatments maintained membrane integrity and high energy levels,also alleviated declination of energy enzyme activities and delayed aril breakdown.Coating treatment was better than heat treatment.(6)Relationships between mitochondria energy metabolism and phenolic metabolism during senescence in post-harvest grapes fruit were investigated in this study.With extension of storage time,cell membrane permeabilities and MDA contents increased;mitochondrial protein contents and energy metabolism enzyme activities decreased;energy levels and EC were in a loss state.Contents of total phenolics,flavonoids,anthocyanins,tannins and chlorophyll decreased;abilities of antioxidant and iron reductions in grape tissue decreased,too.Coating treatment could alleviate grape fruit senescence(P<0.05),and slow down declination of mitochondrial protein contents and energy metabolism enzyme activities after middle storage time,and alleviate declination of phenolics and chlorophyll contents,antioxidant and iron reduction abilities in the latter storage time.Membrane permeabilities and MDA contents were significant negative with energy levels,EC,contents of mitochondrial protein and energy metabolism enzyme activities(R =-0.99--0.93,P<0.01).Membrane permeabilities and MDA contents were significant negative with endogenous antioxidants,antioxidant and iron reducing abilities(R=-0.99?-0.96,P<0.01).Results suggested that senescence of grape fruit would be the results of declinations of mitochondrial protein contents,energy metabolism enzyme activities,energy levels,EC,endogenous antioxidants,antioxidant and iron reduction abilities during storage.Coating treatment may maintain higher mitochondrial proteins contents,metabolic enzyme activities,energy levels,EC endogenous antioxidants contents,antioxidation and iron reduction abilities,thus slowed down membrane integrity damage and delayed senescence.(7)Changes in energy levels,cell wall metabolism and electron ultra-structure of inner pericarp in grape fruits during aril breakdown were studied.With extension of storage time,electron ultra-structure of inner pericarp in grape fruits damaged from density to big hole.Development of aril breakdown,decay rate and membrane permeability were higher with extension of storage time(from day 0 to day 40),while hardness,energy levels and energy charge were lower.Cell wall-degrading enzyme activities of PQ PE and Cx increased.Enzyme activities of ?-Gal decreased in 30 days,and then increased rapidly.Cell wall components of proto-pectin,cellulose and semi-cellulose decreased,but water soluble pectin rose at early storage time,late downward.Aril breakdown and softness were close relations with changes of energy levels,cell wall metabolism and ultra-structure of grape fruit.Correlation analysis showed energy contents(ATP,ADP and AMP)were negatively correlated with aril breakdown indexes(R =-0.95,-0.94,-0.84,P<0.01),but no obvious correlation with EC.Contents of proto-pectin,water soluble pectin,cellulose,semi-cellulose were significantly negative correlation with aril breakdown indexes(R =-0.95,-0.80,-0.94,-0.98,P<0.01).Cell wall-degrading enzyme activities of PG.PE and Cx showed positive correlation with aril breakdown indexes(R = 0.96,0.86,0.96,P<0.01),but no obvious correlations with cell wall-degrading enzyme activities of?-Gal.Treatments of coating and heat combination with calcium delayed fruit aril breakdown and ultra-structure damage by maintaining integrity of cell membrane and higher energy status,inhibiting transformation of proto-pectin to water soluble pectin,inhibiting activities of cell wall-degrading enzymes(PG?PE and Cx)and degradation of cell wall components(proto-pectin,cellulose and semi-cellulose),whereas treatments of coat combination with calcium presented better effect than treatment of heat combination with calcium(P<0.05).