Abid Muhammad, Jabbar Saqib, Hu Bing, Hashim Malik Muhammad, Wu Tao, Lei Shicheng, Khan Muhammad Ammar, Zeng Xiaoxiong
College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China; Department of Food Technology, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Pakistan.
College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
Ultrason Sonochem. 2014 May;21(3):984-90. doi: 10.1016/j.ultsonch.2013.12.003. Epub 2013 Dec 13.
Enzymatic browning and microbial growth lead to quality losses in apple products. In the present study, fresh apple juice was thermosonicated using ultrasound in-bath (25 kHz, 30 min, 0.06 W cm(-3)) and ultrasound with-probe sonicator (20 kHz, 5 and 10 min, 0.30 W cm(-3)) at 20, 40 and 60°C for inactivation of enzymes (polyphenolase, peroxidase and pectinmethylesterase) and microflora (total plate count, yeast and mold). Additionally, ascorbic acid, total phenolics, flavonoids, flavonols, pH, titratable acidity, (°)Brix and color values influenced by thermosonication were investigated. The highest inactivation of enzymes was obtained in ultrasound with-probe at 60°C for 10 min, and the microbial population was completely inactivated at 60°C. The retention of ascorbic acid, total phenolics, flavonoids and flavonols were significantly higher in ultrasound with-probe than ultrasound in-bath at 60°C. These results indicated the usefulness of thermosonication for apple juice processing at low temperature, for enhanced inactivation of enzymes and microorganisms.
酶促褐变和微生物生长会导致苹果制品的品质损失。在本研究中，新鲜苹果汁在20、40和60°C下分别采用浴式超声（25 kHz，30分钟，0.06 W cm(-3)）和探头式超声（20 kHz，5分钟和10分钟，0.30 W cm(-3)）进行热超声处理，以灭活酶（多酚氧化酶、过氧化物酶和果胶甲酯酶）和微生物（总平板计数、酵母和霉菌）。此外，还研究了热超声处理对苹果汁中抗坏血酸、总酚、黄酮类、黄酮醇、pH值、可滴定酸度、糖度（°Brix）和颜色值的影响。在60°C下用探头式超声处理10分钟时酶的失活率最高，在60°C时微生物种群被完全灭活。在60°C下，探头式超声处理对抗坏血酸、总酚、黄酮类和黄酮醇的保留率显著高于浴式超声处理。这些结果表明热超声处理在低温下对苹果汁加工具有实用性，可增强酶和微生物的灭活效果。
