Effect of drying methods on qualities of pomegranate arils (Punica granatum L.) | |
| Author | Kingkan Pongtong |
| Call Number | AIT Thesis no.FB-10-16 |
| Subject(s) | Pomegranate--Quality Pomegranate--Drying |
| Note | A thesis submitted in partial fulfillment of the re quirements for 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-10-16 |
| Abstract | The aim of this study was to investigate the effect of drying methods on qualities change of dried pomegranate arils and determine the best mathematical models in describing drying characteristic of pomegranate ari ls in the range of 45-75 o C. The time required to dry pomegranate arils during hot air dr ying from the initial moisture content of 464.02 % (d.b.) to the final moisture content of 6. 18 % (d.b.) was achieved in 5 - 13.5 hr ,for vacuum drying, the time required to dry pomegr anate arils was achieved in 6.5 – 14.5 hr at the above mentioned temperature range. The drying rates increased as the temperature increased with time. Five of the well known semi-th eoretical and empirical models were fitted to both of drying methods. Midilli model has shown an excellent fit to predict drying behavior of the pomegranate arils because this mode l had the highest coefficient of determination ( R 2 ), the least chi-square ( χ 2 ), and the lowest root mean square error (RMSE). The total drying occurs in falling rate, si gnifying the influence of moisture diffusion during the drying. The effective diffusivity of hot air drying varied from 1.1677 x 10 -11 to 8.3763 x 10 -10 m 2 /s over the temperature range and the effective dif fusivity of vacuum drying varied from 9.3416 x 10 -11 to 2.9115 x 10 -10 . Temperature dependence of the diffusivity was well documented by Arrhenius mo dels. The activation energy of moisture diffusion during hot air drying and vacuum drying was found to be 1.85 kJ/mol and 37.04 kJ/mol, respectively. The qualities change of dried pomegranate arils was determined in term of anthocyanin contents, total phenolic contents as we ll as color. The vacuum drying method was provided the better qualities than the hot air drying. The amounts of anthocyanin contents and total phenolic contents were decreased as drying temperature increased both of drying methods. The anthocyanins retention varie d from 27.73 – 47.37 % for hot air driyng and 50.61 - 85.63% for vacuum drying. The po lyphenol retention for hot air drying varied from 45.35 – 55.04 % and 45.35 – 70.11 % for vacuum drying.The parameter L*, a* and b* values of pomegranate arils decreased with d rying temperature. The total color difference increased as drying temperature increase d. The best condition to dry pomegranate arils was the vacuum drying under 45°C. The production from the best condition had 85.63% anthocyanins retention, 70.11% polyphenol retention and the lowest of total color difference. For investigation on the effect of extraction condi tion on the yield of anthocyanin extracted by using water bath shake extraction, the relationship between factors and yield of athocyanin extracted was found to be the second- order model. The optimized condition for extraction was 60°C of extraction temperature a nd 90 min of extraction time. The sensory evaluation of dried pomegranate arils u sed nine-point hedonic scale and evaluated five attributes such as overall, colo r, flavor, sweetness as well as texture preference. The product of vacuum drying under 45°C had the highest score all of attributes. |
| Year | 2010 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. no.FB-10-16 |
| 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 |