Effect of drying methods and conditions on drying kinetics and quality of Indian gooseberry flake = ผลของวิธีและสภาวะการอบแห้งต่อจลนศาสตร์การอบแห้งและคุณภาพของมะขามป้อมเกล็ด

ผู้เขียน

ศิพร เมธาคุปต์

เอกสารที่มา

วิทยานิพนธ์. (2003) 84 หน้า

หัวข้อ:

บทคัดย่อ

Vacuum drying and low-pressure superheated steam drying (LPSSD) of Indian gooseberry flake were carried out at various drying temperatures (65 and 75 °C ) and pressures (7,10 and 13 kPa absolute pressure) to monitor the drying kinetics and quality degradation (in terms of ascorbic acid and color) of the dried product, which is aimed as an ingredient for an Indian gooseberry tea. In terms of drying kinetics, the drying temperature was found to have and effect on the moisture reduction of samples dried both by vacumm drying and LPSSD. However, pressure seemed to have an obvious effect only for LPSSD but only slightly in the case of vacuum drying. Moreover, it was found that the vacuum drying took shorter time to dry the product to the required moisture content than those of LPSSD at every drying condition. The use of a modified Page's equation could adequately describe the dying behavior for every condition studied (R² = 0.9334-0.9868). In terms of the quality of the dried product, it was found that the drying temperature and pressure had almost no effect both the color and ascorbic acid retention of products underwent LPSSD while only the drying temperature had a significantly effect on the color and ascorbic acid retention of products underwent vacuum drying; except drying under vacuum at 75 °C and absolute pressure of 7 kPa, most sample's underwent LPSSD had higher level of ascorbic acid and better color retention thean those underwent vacuum drying. When comparing the products underwent vacuum drying at 75 °C and absolute pressure of 7 kPa it was observed that the level of ascorbic acid retention was similar to those measured in samples underwent LPSSD but higher than those measured in samples underwent vacuum drying at other conditions. The total color difference value of this sample was, however, slightly higher than those dried by LPSSD. Nevertheless, since the color changes are of no concern to the consumers, this condition was proposed as the most favorable condition for drying of Indian gooseberry flake in regard to minimum energy consumption