Effect Of Chitosan And Nisin On The Antioxidant Quality Of Feijoa During Storage

Feijoa sellowiana Berg which is an economical plant with great development potential has both ornamental and medicinal value.It has been reported that Feijoa is rich in nutrients and a variety of biologically active substances.However,its development and utilization are relatively limited.In China,few studies are focused on the antioxidant properties of Feijoa.Moreover,there is no systematic research on the antioxidant characteristics of Feijoa during storage.In this paper,the dynamic changes of antioxidative indexes of Feijoa in different storage periods after treatment with preservatives such as chitosan and nisin were studied usingCoolidge and Unique as test materials.It is found that antioxidant nutritional characteristics of Feijoa fruit is sensitive to the storage period and method.The resarch results paved the way for preserving and extending the shelf life of the Feijoa fruit.1.We studied the changes of antioxidant components,activity and sugar-acid content in pulp of two Feijoa varieties Coolidge and Unique during 4 ? storage conditions.The results demonstrated the glutathione showed an increase and then decrease of the glutathione reductase.The content of ascorbic acid also increased and then decreased with storage time.We also figured out that the soluble sugar and organic acid decrease,while the content of ascorbic acid oxidase increased,Total phenol and total flavonoids increased and then decreased.It is also found that there is a correlation between total phenol,total flavonoids and ascorbic acid.2.We also studied the effect of preservative treatment on the antioxidant properties of Feijoa.Post-harvest treatment with different concentrations of CTS,Nisin and CTS + Nisin all increase the content of antioxidant components(GSH,AsA,TP,TF)during storage,and are related to the treatment of preservatives and treatment doses.The treatment effect of the agent is better than that of using a single preservative.After storage,the GSH content decreased,while AsA,TP,and TF showed a trend of increasing first and then decreasing.The use of preservatives after harvest can significantly increase the content of the above-mentioned antioxidant components during storage,with 2% CTS + 200 mg / L Nisin as the best treatment.3.The effect of preservative treatment on the activity of Feijoa was also studied.Post-harvest treatment with different concentrations of CTS,Nisin and CTS + Nisin affects the GR and ASO activities in the fruit.The research results showed that the GR activity in the fruit during harvest after the harvest of Feijoa showed a trend of rising first and then decreasing.The activity reached its peak after 20 days.Preservative treatment can significantly enhance the GR activity in the fruit.The effect of the treatment is better than that of the single treatment.In the test process,both Coolidge and Unique were treated with2% CTS + 200 mg / L Nisin.During the entire storage process,the activity of ascorbic acid oxidase showed a rising trend and reached the maximum value at the end of storage.At this time,the control treatment had the highest ascorbic acid oxidase activity.The research results showed that the use of different concentrations of preservatives can inhibit the fruit In the ASO activity of 2% CTS + 200 mg / L Nisin treatment,where the inhibitory effect is the best.4.The effect of preservative treatment on the content of Feijoa glutarate was studied as well.During storage,the content of soluble sugar and organic acid in the fruit of Feijoa decreased.Using different concentrations of CTS,Nisin and CTS + Nisin combined treatment can slow down the total sugar and organic acid content in the fruit The decrease has played a good role in maintaining the flavor of the fruit,and the treatment with 1% CTS+ 100 mg / L Nisin has the best effect.At the end of storage(28d),the soluble sugar content of Unique treated fruits with 2% CTS and 1% CTS + 100 mg / L Nisin were 7.46% and8.46% higher than the control treatment;at the end of storage(28d),Coolidge The organic acid content of fruits treated with 1% CTS and 1% CTS + 100 mg / L Nisin was 1.22 times and 1.29 times higher than the control treatment,respectively.