Effect of the aging and hardening process on the quality of glutinous rice cracker | |
| Author | Muanmai Apintanapong |
| Call Number | AIT Thesis no. AE-94-18 |
| Subject(s) | Rice crackers Food--Quality |
| Note | A thesis submitted in partial fulfilment of the requirement for the degree of Master of Science, School of Environment, Resource & Development |
| Publisher | Asian Institute of Technology |
| Abstract | The experiment was conducted to study the effect of aging on physicochemical properties of two milled glutinous rice varieties (RD6 and RD8). The results showed that the content of amylose, protein and gelatinization temperature remained unchanged during storage from 0 up to 4 months. Amylograph curves were analyzed. The RD6 variety gave the decrease trend of peak viscosity during aging up to 4 months. Moreover, the result showed that the decrease in viscosity during cooking at 94 °C of stored rice was less than the fresh one, while the final viscosity on cooking at 94 °C, viscosity on cooling to 50 °C, setback value, and consistency gave no significant difference during aging. For RD8 variety, peak viscosity tended to decrease slightly but it did not show significant difference during aging from 0 up to 4 months. Viscosity on cooling to 50 °C, setback value, consistency, and breakdown value did not show difference significantly. However, final viscosity on cooking at 94 °C tended to increase during aging from 0 up to 4 months. The raw milled rices of both RD6 and RD8 varieties were not different in water uptake rate. Stored rice (from 0 up to 4 months) tended to decrease in water uptake rate, and the water uptake rate tended to increase proportionally to the soaked time. The same samples were used to study the effect of aging on quality of glutinous rice cracker. Volume expansion of rice cracker made from RD6 and RD8 varieties tended to decrease during storage up to 4 months, whereas the hardness of the cracker increased due to the increase in volume expansion. Hardening process also plays an important role in rice cracker quality. From the experiment of hardening process on rice cake prepared from RD6 milled rice, cooling time affected the quality of rice cracker. Hardness of rice cake increased rapidly on first 48 hours, after that it increased slightly. The 72 hours of cooling gave the best quality of cracker due to the highest volume expansion and lowest hardness, while the others had lower volume expansion and higher hardness. Rice cake made from RD6 variety rice with moisture content of 46.51 percent and density of 1000.81 kg/m3 was used to study some thermal properties. The specific heat of rice cake ranged from 2.19 to 2.50 kJ/kg°C with an average value of 2.37 kJ/kg°C in the temperature range of 32 to 64 °C. The specific heat values appeared to increase linearly with an increase in the sample temperature. Thermal conductivity also showed linear relationship with sample temperature, the values of thermal conductivity varied from 0.39 to 0.57 W/m°C with an average of 0.49 W/m°C in the temperature range of 4 to 66 °C. Thermal diffusivity analyzed by Baird and Gaffney method varied from 1.40*10-7 to 1.63*10-7 m2 /sec with an average of 1.53*10- 7 m2 /sec in the temperature range of 6 to 65 °C, while the average value from Fourier's Analysis was 1.60*10-7 m2 /sec. Computed thermal diffusivity value was higher than those analyzed from previous two methods (2.06*10-7 m2 /sec). |
| Year | 1994 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Athapol Noomhorm |
| Examination Committee(s) | Jindal, Vinod Kumar ;Ilangantileke, S.G. ;Vincent, Jean-Claude ;Ngamchuen Kongseree |
| Scholarship Donor(s) | Royal Thai Government |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1994 |