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Longan drying using microwave-hot air and microwave-vacuum |
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| รหัสดีโอไอ | |
| Title | Longan drying using microwave-hot air and microwave-vacuum |
| Creator | 1. Krit Apinyavisit 2. Adisak Nathakaranakule 3. Somchart Soponronnarit |
| Publisher | Joint Graduate School of Energy and Environment |
| Publication Year | 2557 |
| Keyword | combined drying, hot air, longan, microwave, vacuum |
| Abstract | Dried longan Thai economic product with an export revenue of 4,026.3 million baht in 2013, is traditionally produced by a hot air drying method, which takes more drying times and deteriorates qualities of the dried product. To improve the qualities of dried longan, alternative drying techniques, i.e. microwave combined with hot air (MHD) and microwave under vacuum pressure (MVD) were proposed in this study. Longans (Dor variety) were dried from the initial moisture content of 360-400% (d.b.) to the intermediate moisture content of 70% (d.b.) with MHD and MVD, and then further dried by only hot air to the final moisture content of 20% (d.b.) Temperature of hot air with velocity of 0.3 m/s and recycled air of 80% was set at 65 ? C and vacuum pressure was set at10 kPa. The effect of microwave power at 100, 125 and 150 W on longan drying kinetics and qualities of dried longan in terms of color as well as drying energy were studied. Comparison to hot air drying, it was found that the MHD and MVD reduced drying time and specific energy consumption as well as produced dried longan with less redness and yellowness but more lightness. |
| ISBN | 978-616-92228-1-1 |
