Effects of vacuum concentrated sugar infusion and hot-air drying on qualities of sugar ginger

Effects of vacuum concentrated sugar infusion and hot-air drying were studied with Taiwan fat ginger on its qualities and proper water activity for preservation. The results showed that using concentrated sugar infusion of 0.09-0.095 MPa decreased the browning of products. It could control the product in reduced sugar content and preserve it from moisture absorption or crystallization. According to the speed of temperature rising, the process of hot-air drying for sugar ginger was divided into three phases of accelerating, constant speed and decelerating. The phases of accelerating and constant speed were relatively shorter than it of decelerating that carrying on the most of drying process. The appropriate drying parameters in this phase were 70-80℃ for 7-9 hours. By which, the sugar ginger maintained good taste with a favorable water activity (Aw0.69) for products stored.