Effect Of Mild Temperature Combined With Ultra-high Pressure On The Quality Of Black Chokeberry Juice

Black chokeberry(Aronia melanocarpa Elliot)is a perennial cold and drought resistant shrub of Rosaceae.Its fruit is rich in anthocyanins,phenols and other bioactive components,with antioxidant,antiinflammatory and other effects.However,it tastes sour and astringent and its utilization rate is low,which limits the application in food industry.Therefore,it is necessary to develop related products to achieve a win-win situation of ecological and economic effects.In this paper,black chokeberry fruits are taken as the raw material.The technology of de-astringency,blending and medium temperature combined ultrahigh pressure sterilization on the fruit juice of black chokeberry was optimized.The effects of different sterilization methods on the quality of the juice and the changes of each quality index of the juice during the storage period were explored.The main experimental results were as follows:1.The best de-astringency condition of black chokeberry juice is: add 18.5 m L water every 10 m L of original juice and mix with 1.5 m L of 1% gelatin solution,and settle at 15℃ for 15 min.Under this condition,the total tannin removal rate was 30.85%,the condensation tannin removal rate was 41.63%,and the astringency of juice was effectively reduced(92.5%).2.The best mixing scheme of black chokeberry juice is: add 20 ml drinking pure water,add 0.006 g stevioside and 1.2 g sugar to every 10 m L concentrated juice,which effectively increase the sweet(9.3%)and soluble solid content(205.7%),reduce the unpleasant smell and improve the sensory quality.3.The feasible conditions of mild temperature combined with ultra-high pressure treatment are: 300 MPa/7 min combined with 55℃/10 min and 400 MPa/7 min combined with 50℃/6 min.The two combined sterilization methods can make the black chokeberry juice meet the health standard of fruit and vegetable juice beverage in China after storage at 4℃ and 25℃ for 30 days.Mild temperature combined with ultra-high pressure treatment,ultra-high pressure treatment(400 MPa/7 min)and pasteurization(75℃/30 min)can temporarily and effectively kill the microorganisms in the black chokeberry juice,so as to meet the health standard of fruit and vegetable juice drinks.However,the combination of mild temperature and ultra-high pressure treatment can better maintain the content of bioactive components and antioxidant capacity,and reduce the damage to the color and volatile components of the juice than pasteurization.4.The black chokeberry juice had better sensory quality and higher content of bioactive components under 4℃ storage.The quality and safety of juice treated by mild temperature combined with ultra-high pressure(300 MPa/7 min combined with 55℃/10 min and 400 MPa/7 min combined with 50℃/6 min)were better than that treated by ultra-high pressure(400 MPa/7 min).Therefore,mild temperature combined with ultra-high pressure treatment would be a better choice for sterilization of black chokeberry juice.