Study On The Mechanism Of Color Deterioration Of Pomegranate Aril And It’s Preventions During Storage

In this paper, the dominant pomegranate cultivar ‘Yudazi’ and newbreeding cultivar ‘Dongyan’ of henan agricultural university were used to testedmaterials in Xingyang Zhongzhou. Studied on the mechanism of color deterioration ofpomegranate aril and it’s prevention in2012-2013and2013-2014two years for thestorage. Used different package and different temperature storage to postharvestpomegranate fruit, monitored changes of O2and CO2concentration in P1packageduring storage, regularlyed to determine the influence of respiratery rate ofpomegranate in different treatment during storage, browning index of pomegranatearils, sensory evaluation of pomegranate arils and the influence of antioxidantenzymes activity and a series of physiological and biochemical indexes and qualityindexes in order to find the related factors of pomegranate aril color deterioration,tried to clarify the mechanism of pomegranate aril enzymatic browning and discussedthe feasibility measures. The results show:(1)Occurred color deterioration of pomegranate aril was a complicated processwhich is affected by many factors during storage. Browning indexes of pomegranatearil in P1for suitable low temperature by more than200%lower than the roomtemperature during storage, decreased more than40%lower than the roomtemperature of aril tannin content during the storage, rised more than236%lowerthan the room temperature of relative electric conductivity in the whole storage period,rised more than150%lower than the room temperature, adopted suitable package andtemperature could be a long time to maintain the activity of SOD enzyme was on therise and eventually reach a higher level, inhibited the enzyme activity of POD andPPO. So, the mechanism of color deterioration of pomegranate aril may be due to theinappropriate package and temperature conditions during storage, adversed metabolicproduct (such as ethanol, etc.), aril of antioxidant activity (such as tannin, etc.), theability of endogenous rose short time after the rise of weakened (such as SOD),exacerbated membranous peroxidation, resulting in the cell membrane systemstructure (the rapid increase of conductivity) and function are destroyed, regional distribution in the cell is broken, phenolic substrates such as polyphenol oxidase andperoxidase phenol oxidase (POD, PPO) contact, eventually led to the pomegranateseed color deterioration during storage.(2)‘Dongyan’ could storage longer than ‘Yudazi’. The internal quality of fruitand aril appearance was maintained at a high level of pomegranate in P1at0±0.5℃,5±0.5℃after80d, while ‘Yudazi’ only could store about60d. The residual of O2concentration of ‘Dongyan’ in the bag was higher than ‘Yudazi’, CO2concentrationratio of it was low;‘Dongyan’ browning occured than ‘Yudazi’ late more than20d,even if simultaneously browning, browning index more than20%lower than the‘Yudazi’;‘Dongyan’ safe storage period longer than ‘Yudazi’ about20d at0±0.5℃,5±0.5℃, and room temperature, the difference was not obvious;‘Dongyan’ aril tannincontent higher than the ‘Yudazi’ in each period measured, and tannin content indecline of ‘Dongyan’ more than11.3%lower than ‘Yudazi’ throughout the storageperiod;‘Dongyan’ aril Vc, SSC, TA content decline lower than ‘Yudazi’;‘Dongyan’throughout the storage period of rised aril anthocyanin content lower than the‘Yudazi’;‘Dongyan’ in each period measured aril relative conductivity lower than the‘Yudazi’; The ethanol content of ‘Dongyan’ aril ascending velocity more than18%slower than ‘Yudazi’ during the later stage of storage;‘Dongyan’ aril SOD activitymaintained its long period of rise, and the highest activity than ‘Yudazi’ to be higher,PPO activity at various periods during the general rised lower than the ‘Yudazi’, andmaintained rise time longer than ‘Yudazi’20d. Visible,‘Dongyan’ physiologicalmetabolic intensity was lower than ‘Yudazi’, to better maintained the content ofsoluble solids, Vc, tannins, anthocyanins and so on, and to increase the ethanolcontent was relatively slow; their anti-xidative capacity higher than ‘Yudazi’, a strongability to scavenge ROS, which protected the integrity of membrane, maked relativelyconductivity rised slowly, and PPO had low activity, which browning appeared laterthan20d of ‘Yudazi’.(3)The storage effect of pomegranate in P1was better than P2.‘Dongyan’pomegranate in P1package at0±0.5℃、5±0.5℃storage to80d, the fruit appearanceand internal aril were intact, and P2package only could storage to40d. The browingof pomegranate in P1appeared on more than20d later than P2, even appearedbrowning at the same time, its browning index was also far lower than P2, and thelatter was more than66.7%higher than the former; The respiration intensity in P1package measured was overall than P2at0±0.5℃、5±0.5℃, and had a larger changes in room temperature. The tannin content in P1package was higher than that in P2atvarious periods, and the aril tannin content of pomegranate in P1decreased more than32%lower than P2; the VC, SSC, TA content of P1dropped lower than P2during thestorage period; the aril anthocyanins content of pomegranate in P1was less than P2inthe whole storage period at0±0.5℃and5±0.5℃, and was not obvious at roomtemperature; the aril relative electric conductivity of pomegranate in P1were similarwith P2in the early stage of the storage at0±0.5℃and5±0.5℃, and rised by morethan17%of P1lower than P2during the later stage of storage, and the aril relativeconductivity of P1belowed P2at room temperature in the whole storage period. Thearil ethanol content of pomegranate in P1package rised more than34.37%lower thanP2during the storage period; the pomegranates in P1package maintained their arilSOD activity rise-time was longer20d than P2, and the activity of PPO was in therising period, its activity lower than about25%P1. To sum up, the physiologicalstrength of pomegranate in P1package was lower than P2, antioxidant capacity washigher than P2, and suppressed the increase of the relative electrical conductivity andethanol content, and keeped longer to eliminate the ROS, and it was better to keep thecontent of soluble solids, VC, anthocyanin contents and so on.(4) Compared with5±0.5℃, the effectof storage at0±0.5℃is more better, butboth storage temperature significantly better than the room temperature. O2and CO2concentrations of package bags at0±0.5℃lower than5±0.5℃and temperatureduring storage. At0±0.5℃and5±0.5℃, the browning index difference was notsignificant, but both were later than the room temperature more than20d, evenappeared browning at the same time, its browning index was also far below the roomtemperature, both were lower than the room temperature more than60%. The optimallow temperature could make the respiration intensity of pomegranate lower than theroom temperature about22%, the effect was much better than P1package forrespiratory inhibition. At the temperature of0±0.5℃and5±0.5℃storage ofpomegranate, its aril tannin content during the storage period decreased more than14.7%lower than the room temperature, and the Vc, SSC, TA of its aril contentdecline was obviously lower than the room temperature. At the temperature0±0.5℃and5±0.5℃storage of pomegranate, its aril anthocyain content rised slowly in thewhole storage period, and its aril relative electric conductivity rised to48%lower thanthe room temperature in the whole storage period, the aril ethanol content rised alsomore than75%lower than the room temperature;0±0.5℃and5±0.5℃could make rise SOD activity to maintain a longer process, and inhibited the enzyme activity ofPPO. The strength of physiological metabolism was far below room temperature thanthe low optimal temperature storage of pomegranate, the oxidation resistance washigher than room temperature, and inhibited the relative electrical conductivity andthe increase of ethanol content to better maintain SSC, Vc, anthocyain contents and soon, its impact on the indicators was bigger than the influence of package.