Effects Of Ultra High Pressure Treatment On Its Aroma Components, Texture Properties And Peroxidase In Blackberry

Blackberry is a burgeoning berry fruit,which is highly colored and rich in nutritional value,and has the function to eliminate free radicals,anti-oxidation and so on,suitable for blackberry juice,jam and other products.Ultra-high pressure processing technology can preserve fruit and vegetable products natural aroma,color and nutrition.Blackberry product development with the application of Ultra-high pressure technology will enhance the quality and high value-added products,at the same time accords with "green food" as well as "functional food" consumption trend.The paper studied the changes of blackberry flavor and texture properties after different ultra high pressure treatment,and the POD activity in blackberry was also determined.Ultra-high pressure technology for the blackberry products could provide a theoretical basis for further study.Results were as follows:1.The volatile components of two high quality blackberry cultivars hull and boysen were analyzed by HS-SPME and GC-MS;There were thirty-seven and thirty-nine compounds,mainly including alcohols,esters,acids,aldehydes,ketones and other compounds.According to Guadagni aroma value theory and threshold values of volatile compounds,2-heptanol,linalool,hexanal and trans-2-hexenal,ethyl acetate,methyl-2-methylbutyrate,ethyl-2-methylbutyrate,ethyl butyrate et al.Such eight kinds of ingredients can be considered as the most powerful odorants of blackberry.2.At room temperature,200-600MPa pressure to deal with the blackberry juice, compared with the untreated main volatile aroma components changed little,enabling ultra-high pressure to deal with blackberry juice with natural ingredients to maintain flavor.3.Through the optimize test of probe,A/BE-40 probe was more suitable for the texture analysis because of blackberry pulp had a moderate viscosity;The back extrusion test of blackberry pulp after ultra-high pressure treatment indicated that there was no negative variation of blackberry texture parameters. 4.The effects of different pressure,time on POD activity of blackberry of POD were studied at room temperature.The results showed:100MPa and 200MP POD activity increased to a certain extent;While pressure from 200MPa to 600MPa POD activity showed a downward trend;Constant pressure of 500MPa and 600MPa,POD activity showed a rapid decline at the first 10rain?,then followed by a more moderate change,but still a downward trend.The native-PAGE and active staining of POD showed that new isoenzymes appeared when pressure at 100MPa-300MPa isozymes disappeared at 400MPa-600MPa comparing with untreated samples pressure.