Drying Model and Influence of Temperature on Physico-chemical of Soft Dried Pickled Ginger

บทคัดย่อ

This study aimed to develop mathematical drying models and the influence of drying temperatures of soft dried pickled ginger underwent the laboratory-scaled-tray drying system. The initial moisture content of 70.56±0.58 g_water/g_{dry matter} to the final moisture content of 0.17±0.03 g_water/g_{dry matter} on drying temperatures of 50, 60, 70 and 80^oC with a constant air velocity of 0.4 m/s was 13.00, 10.58, 9.08 and 6.83 hr, respectively. Nonlinear least square method is statistical analysis of drying model and the obtained experimental data was applied to five mathematical models (Newton, Henderson and Pabis, Page, Modified Page and Midilli et al.) and the model with the best fit was determined.  The results showed that the Midilli et al. model could describe the drying characteristics at the most satisfactory level because it gave the highest coefficient of determination (0.9967-0.9996), the least chi-square (0.0000-0.0001), and the lowest root mean square error (0.0033-0.0099). The study of influence of temperature on color changes of soft dried pickled ginger in term of CIE- L* a* b* and Munsell systems (Chroma, Hue angle) Total color difference (TCD), Browning index (BI) and Total Sugar was found that the most physical change in color of dried pickled ginger at 80 ^๐C causes an increase of the brown color. When the temperature drying increased, browning index (BI) and total sugar significantly (P < 0.05) increased.