Study On Preparation And Antioxidant Activity Of Blueberry Leaf Extract Compound Preservative

Blueberry is a kind of small berry with sweet and sour taste and unique flavor,which matures in hot and rainy summer,has thin peel and rich juice,and is easy to rot and deteriorate when stored at room temperature.The content of nutrients in blueberry leaves is not inferior to that of blueberry fruits,but abandoned blueberry leaves are often treated by incineration,which not only wastes resources,but also pollutes the environment on which we live.At present,the combination of cold storage and chemical preservation has become the most commonly used storage method for small berries such as blueberries.Although chemical preservation treatment can prolong the shelf life of blueberries,it is also accompanied by food safety problems and environmental pollution problems.Therefore,it is of great significance to develop a safe and nontoxic natural biological preservative.In this experiment,the "Bluecrop" blueberry leaves and carboxymethyl chitosan,a natural preservative from animal sources,were selected as the research objects.Through the study of its antioxidant properties,the compound preservative with strong antioxidant properties was selected.The obtained compound preservative was applied to "brigitta" blueberries for storage experiment.Through measuring the changes of physicochemical properties and antioxidant properties of blueberry fruits treated with different concentrations of compound preservative during storage,the preservation effect of blueberry leaves extract compound preservative on blueberries was analyzed,which provided a theoretical basis for the application of blueberry leaves extract compound preservative in fruit and vegetable preservation.The research results are as follows:(1)For blueberry leaf extract and carboxymethyl chitosan(CMCTS)antioxidant properties research shows that the content is 1.5% CMCTS coating liquid oxidation resistance of the strongest,the same mass concentration of blueberry leaf extract and blueberry leaf extract in the compound fresh-keeping agent,with 1.5% CMCTS compound blueberry leaf extract the oxidation resistance of compound fresh-keeping agent significantly stronger than the blueberry leaf extract.Principal component analysis showed that 3.5 mg/m L blueberry leaf extract +1.5%CMCTS and 4.0 mg/m L blueberry leaf extract +1.5% CMCTS had strong comprehensive antioxidant capacity.(2)Different coating processing can postpone the blueberries to rot,preservation of its significant effect,by 4.0 mg/m L blueberry leaf extract + 1.5% CMCTS of blueberry most sensory properties and good physical and chemical composition of reserves,the weightlessness rate,decay index,sensory evaluation,fruit hardness,and so on 10 counts ofphysical and chemical indicators were significantly better than the control group.(3)The antioxidant components and antioxidant capacity of blueberries were significantly different after different coating treatments.Among them,the nutritional components,antioxidant enzymes and antioxidant capacity of blueberries treated with4.0mg/m L blueberry leaf extract +1.5% carboxymethyl chitosan coating were significantly better than those of the control group.(4)Based on the antioxidative effect of the compound preservative of blueberry leaf extract and its storage and preservation effect on blueberry fresh fruit,the conclusion was drawn that the preservation effect of 4.0mg/m L blueberry leaf extract +1.5% CMCTS coating was the best.