This research was designed to study the effects of chitosan and citric acid (CA) on pericarp browning and polyphenol
oxidase (PPO) activity of longan fruit. The experiment was conducted by dipping longan fruit in 1.2% (w/v) chitosan coating
solution containing 1.0% CA (pH 3.3) for 2 min, in 1.0% CA solution (pH 2.6) for 2 min, and in distilled water for 2 min as
a control. The treated fruits in each treatment were then packaged in a foam tray, wrapped with 11 μm PVC film and stored
at 5°C, 95% RH for 27 days. Pericarp browning, pericarp color, pericarp pH, titratable acidity (TA), weight loss, polyphenol
oxidase (PPO) activity, and total phenol were monitored during storage. The results revealed that interaction between
chitosan and CA demonstrated the best treatment in postponement of pericarp browning, which was indicated by the lowest
browning index and high L* value, chroma, and hue angle. Based on browning index, the fruits treated with citric acid alone
and the control fruits were not acceptable after 20 days, which those treated with both CA and chitosan were still acceptable
after 27 days of storage. TA had a correlation with the pericarp pH and browning index. Chitosan mixed with citric acid
exhibited a higher efficacy in preventing TA degradation in pericarp and maintaining low pericarp pH, compared to 1.0% CA
treatment. In addition, low PPO activity and high total phenol content were found when CA was applied in combination with
chitosan during storage.
This research was designed to study the effects of chitosan and citric acid (CA) on pericarp browning and polyphenoloxidase (PPO) activity of longan fruit. The experiment was conducted by dipping longan fruit in 1.2% (w/v) chitosan coatingsolution containing 1.0% CA (pH 3.3) for 2 min, in 1.0% CA solution (pH 2.6) for 2 min, and in distilled water for 2 min asa control. The treated fruits in each treatment were then packaged in a foam tray, wrapped with 11 μm PVC film and storedat 5°C, 95% RH for 27 days. Pericarp browning, pericarp color, pericarp pH, titratable acidity (TA), weight loss, polyphenoloxidase (PPO) activity, and total phenol were monitored during storage. The results revealed that interaction betweenchitosan and CA demonstrated the best treatment in postponement of pericarp browning, which was indicated by the lowestbrowning index and high L* value, chroma, and hue angle. Based on browning index, the fruits treated with citric acid aloneand the control fruits were not acceptable after 20 days, which those treated with both CA and chitosan were still acceptableafter 27 days of storage. TA had a correlation with the pericarp pH and browning index. Chitosan mixed with citric acidexhibited a higher efficacy in preventing TA degradation in pericarp and maintaining low pericarp pH, compared to 1.0% CAtreatment. In addition, low PPO activity and high total phenol content were found when CA was applied in combination withchitosan during storage.
การแปล กรุณารอสักครู่..
