การศึกษาหาแนวทางในการอบแห้งกระเทียมที่เหมาะสม

Appropriate Strategy for Drying Garlic

Name: ณรงค์ศักดิ์ แก้วนิล

Organization : มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

Name: Narongsak Kaewnin

keyword: Garlic

; Diffusion Coefficient

; Vitamin C

; Volatile Oil Matter

Abstract: The objective of this research was to study the influences of drying temperatures and air velocities on the drying rate and the garlic qualities. The drying conditions were drying temperatures of 50, 60 and 70?C and air velocities of 0.7 and 1.7 m/s. The initial and final moisture contents of garlic were in range of 180 – 200 and 5 – 15%d.b., respectively. Qualities of garlic considered in this study were shrinkage, color, vitamin C and volatile oil matter.The experimental results for both peel clove and garlic clove drying have shown that the decrease of moisture content could be divided into two falling rate periods. In the first falling rate period, the drying rate increased with the increase of drying temperature and air velocity. For the second falling rate period, the drying rate was limited by diffusion mechanisms. The diffusion coefficient depended solely on the temperature. From the experimental results, they were indicated that the effective diffusion coefficient of peel clove was relatively higher than that of the garlic clove. The critical moisture content varied between 67 and 122 %d.b. for peel clove and 57 – 120 %d.b. for garlic glove. Garlic structure changed when it exposed to hot air. Higher temperature caused larger pores inside the garlic tissues. This resulted in the lower degree of shrinkage of garlic dried at high temperature. Color of garlic was generally varied with drying time and temperature. Higher temperature and longer drying time reduced the L value and increased the a and b value. The L value for the garlic clove was higher than that of the peel garlic when it was dried at low temperature whilst the a and b value of both cases were not different. However, no significant difference of L, a, and b values were found for drying at the higher temperature. Loss of vitamin C and volatile oil varied with drying time and drying air temperature. The peel garlic lost more vitamin C than the garlic clove, but the garlic clove lost more volatile oil than the peeled garlic when the garlic clove was dried at low temperature. Vitamin C contents lost from the clove and peeled garlic were not much different for drying at high temperature. However, at the low temperature, the lower volatile oil loss was found in garlic clove drying than in peeled garlic drying. Moreover, velocity of drying air had no significant effect on garlic qualities.

มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

Address: กรุงเทพมหานคร

Email: info.lib@mail.kmutt.ac.th

Name: สมเกียรติ ปรัชญาวรากร

Role: อาจารย์ที่ปรึกษา

Created: 2546

Issued: 2005-08-31

Modified: 2554-03-05

วิทยานิพนธ์/Thesis

ISBN: 9744562935

CallNumber: ET559

tha

DegreeName: วิศวกรรมศาสตรมหาบัณฑิต

Level: ปริญญาโท

Descipline: เทคโนโลยีพลังงาน

Grantor: มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

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