| Author | Thitiworn Rattanathitikul |
| Call Number | AIT Thesis no.FB-10-17 |
| Subject(s) | Thunbergia--Drying
|
| Note | A thesis submitted in partial fulfillment of the requirements fo r the degree of Master of Science in Food Engineering and Bioprocess Technology, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. no.FB-10-17 |
| Abstract | General process of herbal tea production has two main processing such as pretreatment and drying. The objective of this work is to study the effect of different blanching pretreatments and drying conditions on qualities of dried Rang Chuet strip leaves and its inf usion. There are two blanching methods, namely; hot water and steam pretreatment varying blanching times were treated in Rang Chuet strip leaves prior to drying. Water blanching at 98 ± 2 º C for 3.0 min was effectively Rang Chuet strip leaves blanching from t he results in the efficiency on peroxidase enzyme inactivation and preserving the amount of total chlorophyll content and color when compared to steam blanching. The drying process of Rang Chuet strip leaves by different three drying methods, namely; hot air drying, vacuum drying and infrared drying at temperature of 50, 55, 60 and 65°C were investigated to understand of drying characteristics and effect on qualities of Rang Chuet leaves. The result of drying characteristics is distinctly that infrared me thod could reduce drying time by more than hot air and vacuum drying. Two mathematical drying models which are Simple Exponential equation (Lewis’s model) and General Page equation (Page’s model) were built up to de scribe the behavior of Rang Chuet leaves dryings. Page’s equation gave good fit model for predicting the change of moisture content with time and to be the most suitable model for explaining and understanding the drying behavior for three drying methods (hot air, vacuum and infrared drying) compa ring the coefficient with the highest coefficient of determination ( R 2 ), the lowest of root mean square error (RMSE), and the lowest of reduced chi - square ( 2 ). The value of kinetic constant (k) was increased linearity by the i ncreasing in drying temperatu re. The physical properties which are color and rehydration ratio of dried Rang Chuet leaves were test ed. The increase of drying temperature resulted in inferior color quality except in vacuum dried samples. Oppositely, the effect of increasing drying tem perature gained in better rehydration characteristics of dried leaves. Total phenolic content of dried Rang Chuet leaves powder were investigated using the Folin - Ciocalteu method. The results indicated that total phenolic content were degraded with the inc reasing drying temperature. The total phenolic content of vacuum at 50 o C gave the highest values. In conclusion, consideration on all performance qualities of dried Rang Chuet leaves and its infusion, vacuum drying at 5 0 º C was the most appropriate drying of Rang Chuet leaves and Rang Chuet herbal tea production. It gave result of high qualities in appearance (greenness and brightness) , total phenolic content and sensory acceptability. Therefore, vacuum drying is one of recommended drying methqualities of Rang Chuet products.ods to receive better |
| Year | 2010 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. no.FB-10-17 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Food Engineering and Bioprocess Technology (FB) |
| Chairperson(s) | Athapol Noomhorm; |
| Examination Committee(s) | Rakshit, Sudip Kumar;Anal, Anil Kumar; |
| Scholarship Donor(s) | RTG Fellowship; |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2010 |