Study On The Influence Of Processing And Adding Different Juices On The Quality In Coudy Jinfeng Pear Juice

Jinfeng pear was used as the raw material to analyze the effect of processing on the quality of juice.The changes of flavor were studied by using different packaging and illumination,and improved the processing technology on the color and stability of mixed pear juice.Refine the peeling,crushing and homogenizing to explore the effects of different processing on the quality and stability of Jinfeng pear juice,and explore the change in packaging and illumination on the quality and flavor.According to the above research,a processing technology was selected for Jinfeng Pear,which the NFC juice rich in Vc was added instead of ascorbic acid color-protecting agent to develop a "Food clean label" mixed Jinfeng Pear Juice.This experiment can provide scientific basis for the processing industry of Jinfeng pear,and a feasible solution for promoting the concept of "Food clean label" and the development of the mixed Jinfeng pear juice industry.The main results were as follows:1.Used 4℃crushing temperature without peeling and homogenization pressure at 40 MPa has a good effect on the quality and stability of Jinfeng pear juice.High temperature crushing and peeling with hot alkaline immersion could cause the quality to be significantly reduced,and homogenization treatment would improve the stability of Jinfeng pear juice.Mechanical peeling better preserved the Vc and TA in Jinfeng pear juice,reduced turbidity and centrifugal precipitation,and made pear juice lighter in color;while peeling with hot alkaline immersion caused Jinfeng pear juice increased in system instability.The high-temperature crushing temperature of 93℃reduced the juice yield,the turbidity increased,and the content of TSS decreased.Thelow-temperature crushing at 4℃ could obviously improve the turbidity of Jinfeng pear juice.Different homogenization pressures led to the decrease in TA and 40 MPa would better retain the Vc content of Jinfeng pear juice,thereby making the juice system more stable.2.It is better to use glass bottle packaging under light conditions.Different packaging and illumination had significant effects on the quality of Jinfeng pear juice during storage.Light conditions played a crucial role in the degradation of Vc.The pH value of dark was better than light treatment;the b value in dark treatment of PET bottles and composite bags increased fastest;the browning of Jinfeng pear juice in composite bags was the most worst;the packaging with the least effect on Vc degradation was glass bottles but the most worst was the compound bag,meanwhile the Vc content of the dark-treated compound bag was higher than the compound bag.Different packaging and illumination had different degrees of influence on particle size and certain volatile odor components at different storage periods.3.Adding 20% lemon juice has improved the quality and stability of mixed Jinfeng pear juice.When Jinfeng pear juice was added with juice rich in Vc,the color and stability both changed significantly.The addition of lemon juice could better maintain the color of pear juice and improve the stability of the mixed juice.Although kiwi juice could also better inhibit the browning degree,it could not maintain the stability of the system,and would cause turbidity of mixed juice increased.But adding orange juice affected the color of the mixed juice.Compared with adding 10%juice,mixed juice with 20% juice had better effect on the color and stability.It adopted crushing temperature of 4℃,peeling-free treatment method,homogenization pressure of 40 MPa,useing the glass bottle.And 20% lemon juice is added to Jinfeng pear juice to make the mixede juices wihich is better.