Postharvesting Effect And Its Mechanism Of Combination Of Erythorbic Acid And Perforated Packaging On Grifola Frondosa Fruiting Body

Grifola frondosa is one of the important cultivated and exported edible fungi in China with its special taste and high nutrition values.However,the fresh fruiting body of G.frondosa easily deteriorates and senesces rapidly at ambient temperature due to the high levels of respiration rate,metabolic activity and moistrue content,making it have the undesirable changes of appearance and general quality and lose their marketability.Currently,the majority of researches about G.frondosa focused on the strain improvement,bioactivity evaluation and structual analysis of the functional compounds.Very few existed references were involved in the postharvest changes or protect/prolong the shelf life of G.frondosa.Thus,the present study mainly aimed to investigate the effect of different concentrations of EA treatments,combination of EA and perforated film packages treatments on the quality of G.frondosa fruiting body,and eludicate the possible preservation mechanism of 0.1% EA combined with micro-perforation package treatments by determining the sense quality,microstructure,membrane lipid peroxidation,cell wall composition and related hydrolase activity.The main obtained results are as follows:(1)The effect of erythorbic acid(EA)treatments with different concentrations on the quality of G.frondosa fruiting body stored at 4 oC was evaluated.The results showed that 0.1% EA treatment could enhance antioxidases activities(SOD,CAT and POD)with the highest value of 298.40 U/mg protein,2857.74 U/mg protein and 48.33 U/mg protein on 6th,27 th and 24 th,respectively,delaying the increase of weight loss(less 6.01 %),electrolyte leakage(less 45.79 %)and MDA content(less 4.17 nmol/g).Besides,0.1% EA treatment could inhibit the increase of browning degree by reducing PPO activity(less 72.64 U/g)and maintained the higher content of total soluble sugar(over 5.78 mg/g)and total soluble protein(over 2.83 mg/g).(2)Based on 0.1% EA treatment,the effect of different perforated film packages treatments on the quality of G.frondosa fruiting body stored at 4 oC for 27 d was evaluated.The results showed that G.frondosa fruiting body with 0.1%EA+LP1 and 0.1%EA+LP2 treatments was easily shrinking and softening during storage.The quality of G.frondosa fruiting body treated with sealed package was likely to deteriorate due to the formation of condensed water during the middle and later storage periods.However,micro-perforation film packages treatments were more conductive to the heat dissipation and water retention of G.frondosa fruiting body.0.1%EA+MP2 treatment could maintain the lower value of weight loss(less 4.30%)and browning degree(less 3.88),and the higher value of moisture(over 90%),total soluble sugar(over 9.66 mg/g)and total soluble protein(over 3.25 mg/g).The results indicated that the combination of EA and micro-perforation film packages treatments had a better effect on the preservation of G.frondosa fruiting body.(3)The possible preservation mechanism of G.frondosa fruiting body treated with the combination of EA and micro-perforation film package(0.1%EA+MP2)was studied.The results showed that 0.1%EA+MP2 treatment could inhibit the increase of chitinase(less 8.02 U/g),?-1,3-glucanase(less 0.708 U/g),cellulase(less 28.40 U/g)and protease(less 60.84 U/g)actitvities,delaying the degradation rate of chitin and cellulose,reducing the process of membrane lipid peroxidation and maintaining the higher value of firmness(over 25.45 g).0.1%EA+MP2 treatment could reduce the increase of browning degree by inhibiting PPO activity(less 68.13 U/g).Besides,by analyzing the changes of sense quality and microstructure of G.frondosa fruiting body,it was also found that 0.1%EA+MP2 treatment could maintain better sense quality and microstructure.Thus,the combination of EA and micro-perforation film package treatments could extend the shelf life of G.frondosa fruiting body.