| In this paper,we used the experiment designs of single factor,orthogonal experiment design and response surface optimization to analyze the change of total antioxidant capacity,peroxidase(POD),polyphenol oxidase(PPO),anthocyanin,total phenol content,total content of VC and other physical and chemical indicators in blueberry juice about the impact of pressure,temperature and time,when it had been treated by ultra-high pressure.Aimed at the ultra-high pressure technology in the blueberry juice products to provide theoretical basis for industrial production and technical support,The results of the study are as follows:1)The effect of ultrahigh pressure on the total antioxidant capacity of blueberry juice was studied.The results showed that the effect of ultrahigh pressure on the total antioxidant capacity of blueberry juice from strong to weak was temperature>time>pressure.The optimum process parameters were 400MPa,the time was 10min and the temperature was 25 ?.Under this condition,the total antioxidant capacity of blueberry juice was 97.4%,and the retention effect was better.While the optimum process conditions were 424.7MPa,the time was 11.5min and the temperature was 19?,The theoretical value of the total antioxidant capacity of blueberry juice was 98.74%and the actual value was 97.82%.As for the storage of blueberry juice products,when the period of storage is long,the blueberry juice products should be placed under low temperature conditions,in contrast when the period of storage is short should be stored at the appropriate higher temperature.2)POD and PPO in blueberry juice were influenced by ultra-high pressure.Under the conditions of ultra-high pressure treatment of 300?500MPa,5?15min and 10?40 ?,The primary and secondary order of the residual activity of POD was temperature>pressure>.time.The primary and secondary order effects on the residual activity of PPO were time>temperature>pressure.The optimum treatment conditions of passivation peroxidase(POD)were as follows:pressure 500MPa,time 5min and temperature 40 ?,after treatment,the residual activity of the enzyme decreased to 49.13%;The optimum conditions for the treatment of polyphenol oxidase(PPO)were:pressure 500MPa,time 15 min and temperature 10?,after treatment,the residual activity of the enzyme decreased to 4.776%;The optimum conditions for the deactivation of the two enzyme residues were:pressure 500MPa,time 15 min and temperature 10?.3)The influnce of ultra-high pressure on anthocyanin in blueberry juice from strong to weak is pressure>time>temperature.The optimum combination of the influencing factors was 400MPa,and the content of anthocyanins in blueberry juice was the highest when the holding time was 5min at 20?.The primary and secondary order of the effect of the ultra-high pressure treatment on the total phenolic content is temperature>time>pressure.The optimum process parameters were 500MPa,the time was 5min and the temperature was 10?.Under this condition,the total phenol content of blueberry juice was 96.79%,and the retention effect was better.The importance of ultra-high pressure on the influencing factors of VC content in blueberry juice was temperature>time>pressure.The best combination of influencing factor was the pressure 600 MPa,time 20 min and temperature 20 ?..4)There was no significant difference in the protein content and pH value of the blueberry juice.The protein content in the range of 1.1-1.5mg/mL,The PH value was between 3.28 and 3.44.Ultra-high pressure on the blueberry juice had a significant impact on the color,and the pressure,time and temperature all have an impact on the AL,And the value of Aa showed the partial about red and green which is due to the changes of pressure and time,the impact of temperature is not significant.Only the time of ultrahigh pressure treatment has an effect on Ab values,Only the time of ultrahigh pressure treatment had an effect on Ab,and the effect of other factors on Ab was not significant.When the pressure is 200MPa,the AE is a minimum of 0.23. |
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