An Kejing, Tang Daobang, Wu Jijun, Fu Manqin, Wen Jing, Xiao Gengsheng, Xu Yujuan
Sericulture and Agri-Food Research Institute Guangdong Academy of Agricultural Sciences/Key Laboratory of Functional Foods Ministry of Agriculture/Guangdong Key Laboratory of Agricultural Products Processing Guangzhou China.
Food Sci Nutr. 2019 Jun 28;7(8):2537-2545. doi: 10.1002/fsn3.1103. eCollection 2019 Aug.
The effects of pulsed vacuum osmotic dehydration (PVOD) and ultrasound osmotic dehydration (USOD) on drying characteristics and quality attributes of ginger were investigated. PVOD was subjected to pulsed vacuum at 13 kPa for 30 min, and USOD was subjected to ultrasound with the frequency of 40 kHz for 30 min. After PVOD and USOD treatments, the samples were then dried at intermittent microwave & air-drying oven with an output of 700 W and temperature of 60°C to the final moisture content of 0.12 g water/g d.w. The results showed PVOD and USOD treatments could improve the total phenolic contents by -1.8% to 16.4%, total flavonoid content by 7.7%-18.7%, DPPH radical scavenging by 9.5%-12.2%, and ABTS+ antioxidant activity by 17.8%-27.4%, although they prolonged the later stages drying of ginger. Besides, the PVOD- and USOD-pretreated dried samples had less brownings than the untreated-dried samples which could be attributed to the inactivation of polyphenol oxidase (PPO) and peroxidase (POD). The PPO activity was significantly reduced in the PVOD and USOD ginger, whereas POD activity was decreased in USOD ginger but increased in PVOD ginger. Moreover, PVOD pretreatment also led to a better preservation of volatile profiles and cell structure than USOD treatment. Therefore, both PVOD and USOD are effective pretreatments for drying of ginger.
研究了脉冲真空渗透脱水（PVOD）和超声渗透脱水（USOD）对生姜干燥特性和品质属性的影响。PVOD在13 kPa的脉冲真空下处理30分钟，USOD在40 kHz的频率下超声处理30分钟。经过PVOD和USOD处理后，样品随后在输出功率为700 W、温度为60°C的间歇式微波与空气干燥箱中干燥至最终水分含量为0.12 g水/g干重。结果表明，PVOD和USOD处理可使总酚含量提高-1.8%至16.4%，总黄酮含量提高7.7%-18.7%，DPPH自由基清除率提高9.5%-12.2%，ABTS+抗氧化活性提高17.8%-27.4%，尽管它们延长了生姜后期的干燥时间。此外，经PVOD和USOD预处理的干燥样品比未处理的干燥样品褐变程度更低，这可能归因于多酚氧化酶（PPO）和过氧化物酶（POD）的失活。PVOD和USOD处理的生姜中PPO活性显著降低，而USOD处理的生姜中POD活性降低，PVOD处理的生姜中POD活性增加。此外，与USOD处理相比，PVOD预处理还能更好地保留挥发性成分和细胞结构。因此，PVOD和USOD都是生姜干燥的有效预处理方法。
