Study On Quality Changes Of Fresh-cut Jackfruit During Ordinary And Low Temperature Storage

A series of physiological and biochemical changes and quality deterioration will occur in fresh-cut jackfruit during the storage,affecting its appearance and flavor.In this paper,the LF-NMR technology was used to analyze the water migration of fresh-cut jackfruit during storage at 25℃from a microscopic perspective.Combined with GC-MS,UHPLC-MS/MS technology and the changes of various physiological characteristics,the formation causes of similar transparency phenomenon of fresh-cut jackfruit during storage were discussed.At the same time,the comprehensive quality evaluation model of fresh-cut jackfruit was established by cluster analysis and principal component analysis under the control of storage temperature of 4℃.The main findings of this paper are as follows:(1)The study found that the L*,a*,b*,hardness,adhesivenessand chewiness of fresh-cut jackfruit changed significantly after 3h at 25°C(P<0.05);According to the change of volatile components in fresh-cut jackfruit at 25°C,the relative contents of butyl acetate,isoamyl acetate,propyl valerate and isobutyl isovalerate in jackfruit decreased with the prolongation of storage time,and the relative contents of isovaleraldehyde,isovaleric acid and phenylpropanal increased with the prolongation of storage time,while the volatile components such as hexanal,octanal,decanal,nonanal,ethanol and 1-decanol were added during storage.(2)The activities of PPO,POD,PME,PG and C_X in fresh-cut jackfruit increased rapidly within a short time after cutting at 25℃,and there is obvious water migration between the cell wall water,the cytoplasmic water,the interstitial water and the vacuole water,which lead to the weight loss,relative conductivity,TA,TSS and water-soluble pectin contents increased with the storage time.(3)The relative contents of phytofluene,violaxanthin,antheraxanthin,lutein,zeaxanthin,β-cryptoxanthin,α-carotene,β-carotene in fresh jackfruit and transparent area tissues are significantly different(P<0.05).Combined with the analysis of carotenoid metabolic pathway in higher plants and the change of ABA content in fresh-cut jackfruit at25℃,the cause of the phenomenon may be that the cutting action causes the respiration of freshly cut jackfruit to be strengthened and cell wall water and liquid bubble water migrate to cytoplasmic water for respiration in cells during the initial storage period.With the extension of storage time,the enzymolysis reactions of PME,PG and C_X make the permeability of cells and organelle membranes continuously increase,and the hardness,adhesiveness,chewiness and resilience of fresh-cut jackfruit decrease continuously.At the same time,the enzymatic reaction of PPO,POD and the degradation of carotenoids during storage cause the color of fresh-cut jackfruit to gradually darken,and the edible quality of fresh-cut jackfruit decreased seriously.(4)By measuring the color,texture,relative conductivity,weight loss rate and water migration of freshly cut jackfruit during refrigeration at 4°C,a comprehensive quality evaluation model of freshly cut jackfruit at 4°C,which could provide reference for the processing and preservation of fresh-cut jackfruit in the future.