Low-temperature storage is extensively used to optimize the postharvest life of various fresh fruits.However,red pitahaya(Hylocereus polyrhizus)fruits are sensitive to chilling injury(CI),which leads to the limitation...Low-temperature storage is extensively used to optimize the postharvest life of various fresh fruits.However,red pitahaya(Hylocereus polyrhizus)fruits are sensitive to chilling injury(CI),which leads to the limitation of low-temperature storage.In this study,red pitahaya fruits were stored at 2,4,6,8,and 10℃,respectively,for 27 days to determine the appropriate storage temperature.During the storage of red pitahaya fruits,storage at 8℃ was more effective in suppressing decay and maintaining quality than other low temperatures.Lowtemperature(2,4,and 6℃)storage decreased weight loss(WL)and maintained higher content of titratable acidity(TA),soluble sugars(SS),and total phenolics(TP)but different degrees of CI were detected.No CI was observed at 8℃ and 10℃.Red pitahay as stored at 8 and 10℃ were associated with better color evaluation,lower electrolyte leakage(EL),respiration rate,and lipoxygenase(LOX)activity,and higher fruit firmness,superoxide dismutase(SOD)activity,and catalase(CAT)activity.However,higher storage temperature(10℃)resulted in higher metabolic activity leading to lower quality and antioxidant capacities compared with 8℃.Therefore,our results demonstrated that red pitahaya stored at 8℃ exhibited a protective effect on fruit quality and resisted CI development during storage.展开更多
The fungistatic activity of a lactic acid bacterium, which had been isolated from yellow pitahaya cultures, against fungi associated with basal rot(Fusarium oxysporum and Fusarium fujikuroi) was measured in the presen...The fungistatic activity of a lactic acid bacterium, which had been isolated from yellow pitahaya cultures, against fungi associated with basal rot(Fusarium oxysporum and Fusarium fujikuroi) was measured in the present study. Its activity was assessed in three fractions: fermented(S1), metabolic products(S2), and biomass(S3), using two fermentation substrates: Man Rogosa Sharpe agar(MRS) and potato dextrose agar(PDA). The bacterium was molecularly identified as Lactobacillus plantarum. S3 reduced F. fujikuroi growth by 100% over 48 h of fermentation, which occurred during the stationary phase of bacterial growth. The three fractions' fungistatic activity against F. fujikuroi depended on the substrate employed. The fermentation kinetic parameters for L. plantarum indicated that its specific growth rate was 0.46 h^–1, with 93.63% substrate consumption, 0.045 kg kg^–1 cell yield, and 0.54 kg kg^–1 product yield. The kinetic parameters calculated will allow for bacteria production scaling. These in-vitro trials reveal L. plantarum's possible application as a biocontrol agent for diseases associated with Fusarium. However, further ex-vivo and in-vivo researches are required to demonstrate its behavior in crops.展开更多
基金J.X.and J.M.gratefully acknowledge the funding from Key Project of Science and Technology Commission of Shanghai Municipality,Grant No.19395800100Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation,Grant No.17DZ2293400.
文摘Low-temperature storage is extensively used to optimize the postharvest life of various fresh fruits.However,red pitahaya(Hylocereus polyrhizus)fruits are sensitive to chilling injury(CI),which leads to the limitation of low-temperature storage.In this study,red pitahaya fruits were stored at 2,4,6,8,and 10℃,respectively,for 27 days to determine the appropriate storage temperature.During the storage of red pitahaya fruits,storage at 8℃ was more effective in suppressing decay and maintaining quality than other low temperatures.Lowtemperature(2,4,and 6℃)storage decreased weight loss(WL)and maintained higher content of titratable acidity(TA),soluble sugars(SS),and total phenolics(TP)but different degrees of CI were detected.No CI was observed at 8℃ and 10℃.Red pitahay as stored at 8 and 10℃ were associated with better color evaluation,lower electrolyte leakage(EL),respiration rate,and lipoxygenase(LOX)activity,and higher fruit firmness,superoxide dismutase(SOD)activity,and catalase(CAT)activity.However,higher storage temperature(10℃)resulted in higher metabolic activity leading to lower quality and antioxidant capacities compared with 8℃.Therefore,our results demonstrated that red pitahaya stored at 8℃ exhibited a protective effect on fruit quality and resisted CI development during storage.
基金the Administrative Department of Science, Technology, and Innovation, Colciencias, Asoppitayathe Inter-American Development Bank IDB for funding。
文摘The fungistatic activity of a lactic acid bacterium, which had been isolated from yellow pitahaya cultures, against fungi associated with basal rot(Fusarium oxysporum and Fusarium fujikuroi) was measured in the present study. Its activity was assessed in three fractions: fermented(S1), metabolic products(S2), and biomass(S3), using two fermentation substrates: Man Rogosa Sharpe agar(MRS) and potato dextrose agar(PDA). The bacterium was molecularly identified as Lactobacillus plantarum. S3 reduced F. fujikuroi growth by 100% over 48 h of fermentation, which occurred during the stationary phase of bacterial growth. The three fractions' fungistatic activity against F. fujikuroi depended on the substrate employed. The fermentation kinetic parameters for L. plantarum indicated that its specific growth rate was 0.46 h^–1, with 93.63% substrate consumption, 0.045 kg kg^–1 cell yield, and 0.54 kg kg^–1 product yield. The kinetic parameters calculated will allow for bacteria production scaling. These in-vitro trials reveal L. plantarum's possible application as a biocontrol agent for diseases associated with Fusarium. However, further ex-vivo and in-vivo researches are required to demonstrate its behavior in crops.
