Effect of Sterilization Treatments on the Quality of Blueberry Juice

Microorganisms, physical-chemical properties and sensory evaluation of blueberry juice by pasteurization, UHT and microwave treatment were investigated. Results indicated that the three treatments all met thecommercial sterilization requirements. The pH value, total soluble solid and total acid content of blueberry juice had no changes for the samples treated by the three methods. Pasteurization effectively maintained the suspension stability, color and anthocyanins content of blueberry juice. And the free radical scavenging ability against DPPH of the Pasteuring samples was lower than that of the microwave treatment, where the free radical scavenging ability against DPPH of microwave treatment was up to 88.24%. The sensory evaluation showed that the blueberry juice by microwave treatment was closest to the control sample than the other treatments, especially in color and aroma. Therefore, microwave treatment can effectively inactivate the microorganisms and keep the physical-chemical properties, sensory evaluation and antioxidant activity of blueberry juice.