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Effects of Hot Air and Freeze Dnying Methods on Physicochemical Properties of Thai Hom Mali Rice Grass Juice Powder |
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| รหัสดีโอไอ | |
| Creator | 1. Sunan Parnsakhorn 2. Jaturong Langakin 3. Siriporn Siamsiri 4. Wilaiporn Jantaboon |
| Title | Effects of Hot Air and Freeze Dnying Methods on Physicochemical Properties of Thai Hom Mali Rice Grass Juice Powder |
| Publisher | Department of Agriculture |
| Publication Year | 2556 |
| Journal Title | Thai Agricultural Research Journal |
| Journal Vol. | 31 |
| Journal No. | 1 |
| Page no. | 78-89 |
| Keyword | น้ำคั้นต้นข้าวโพดอ่อนผง, ทำแห้งแบบเหยือกแข็ง, คลอโรฟิลล์, ปริมาณน้ำอิสระ, ทำแห้งด้วยลมร้อน, rice grass juice powder, freeze dry, chlorophyll, water activity, hot air drying |
| URL Website | http://at.doa.go.th/journal |
| Website title | Thai Agricultural Research Journal |
| ISSN | 0125-8389 |
| Abstract | Rice grass juice powders were using hot air drying at the temperatures of 40ง and 60งC and freeze drying methods. Their physicochemical properties (freezing point, chlorophyll content, water activity (aw) and colour values (L*,a*,b*) were measured and compared with fresh rice grass juice and rehydration rice grass juice powders. The study has demonstrated that the qualities of freeze-dried powder were higher than that of hot air dried powder. Moreover, the rehydration freeze-dried powder has the similar qualities to the fresh ones. The freezing point of fresh rice grass juice was approximately -1งC which contained the lowest value of total chlorophyll content (0.080 mg/g.). The total chlorophyll content of freeze-dried powder increassd from 0.910 to 0.990 mg/g. It was significantly higher than that of hot air dried powder which gave 0.398 and 0.999 mg/g at the temperatures of 60งC and 40งC, respectively. The results revealed that the total chlorophyll content (0.116 mg/g) of rice grass juice powder decreassd after rehydration. Water activity value (aw) of freeze=decreased and was lower than 0.6 which is suitable for powder products. The whiteness, redness and yellowness values of hot air dried powder were increased after drying at the temperature of 40ง and 60งC as compared to that of fresh rice grass juice. The gradual decrease of L*b*and a* values was observed after freeze-drying process. As such, this study indicates that rehydration rice grass juice powder which drying at low temperatures using hot air at 40งC and treeze drying methods, could maintain chlorophyll content and colour quality similar to fresh ones. |
