Effects of different concentrating processes on the quality of reconstituted mulberry juice | |
| Author | Naruedee Chokanuwat |
| Call Number | AIT Thesis no.FB-09-14 |
| Subject(s) | Mulberry Concentrated fruit juices Fruit juices |
| Note | A thesis submitted in partial fulfillment of the requirements 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-09-14 |
| Abstract | In this study, concentration characteristics of mulberry juice were examined during concentration by different concentrating processes, namely, conventional heating (100 °C), microwave heating (770 W), rotary-vacuum evaporator (65 °C, 30 kPa), and microwave-vacuum evaporator (120, 400, and 770 W, 30 kPa). Microwave-vacuum evaporator at 770 under vacuum pressure of 30 kPa W had the highest evaporation rate constant, followed by microwave-vacuum evaporator at 400 W, microwave heating, rotary vacuum evaporator, conventional heating, and microwave-vacuum evaporator at 120 W, respectively. Among microwave-vacuum evaporator, evaporation rate constant increased with increasing microwave output power. The mathematical models were fitted to the experimental data to find the suitable model. The Henderson and Pabis model gave better fit model for the experimental concentration data and to be the most suitable model for explaining and understanding the concentration behavior of mulberry juice concentrate for all concentrating processes with the highest R² values and the lowest RMSE and X² values. For the comparison of the effects of different concentrating process on quality of reconstituted mulberry juice, the results showed microwave-vacuum evaporator at 770 W under vacuum pressure of 30 kPa retained the highest total anthocyanin and total polyphenol contents. The lowest retention of total anthocyanins and total polyphenol was found in reconstituted mulberry juice concentrated by conventional heating. In contrast, microwave-vacuum evaporator retained the lowest DPPH radical scavenging activity, and the highest DPPH radical scavenging activity was found in reconstituted mulberry juice concentrated by conventional heating. Thermal stability of anthocaynins in mulberry juice with initial °Brix of 11.6 were studied during concentration by microwave-vacuum evaporator at 65 °C (30 kPa), 75°C (40 kPa), and 85 °C (50 kPa) until reach the desired final concentration of 65 °Brix. The results indicated that thermal degradation of mulberry anthocyanins followed first order reaction kinetics. The degradation of mulberry anthocyanin increased with increasing concentration time at all temperatures, and mulberry anthocyanins were more drastically degraded at higher temperature. The temperature-dependent degradation was adequately modeled on the Arrhenius equation. The activation energy value for the degradation of mulberry anthicyanins during concentration was 33.09 kJ/mol. The rheological behavior of mulberry juice concentrate of 65 °Brix was investigated. Viscosity was measured at 30, 40, 50, and 60 °C and at the speed of 70, 80, 90, 120, 180, and 200 rpm. An empirical Power law model was used to describe the rheological behavior of mulberry juice concentrate with coefficient of determination (R²) ranged from 0.9909 to 0.9987. The mulberry juice concentrate exhibited a pseudoplastic behavior. An Arrhenius equation was used to describe the effect of temperature on viscosity, and the activation energy value of the mulberry juice concentrate was calculated as 43.90 kJ/mol. |
| Year | 2009 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. no. FB-09-14 |
| 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;Ranamukhaarachchi, S.L.; |
| Scholarship Donor(s) | RTG Fellowship; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2009 |