Chickpea Temperature Profile Development and its Implication under Microwave Treatment

Author: Shaghaf Kaukab, Abhijit Kar, Shiva Dhar, Alka Mishra, Subramanian S. and Baidya Nath Mandal

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Abstract

Non-uniform temperature distribution is the major concern during microwave processing. Generation of heat and temperature during microwave treatment is purely based on the material’s intrinsic properties, therefore different material shows different behaviour. Microwave technology is often employed in legume crops for various reasons such as disinfestation, extraction, drying, roasting, pretreatment during milling operation etc. However, paucity of information on the microwave treatment and temperature behaviour, of legume crops are available. In the present study the temperature profile analysis and distribution are performed in the chickpea seeds at various power level (0– 800W) and treatment time (10 s – 50 s). A domestic-scale microwave at 2450 MHz was used for the experimental purpose to treat chickpeas. Surface temperature distribution was determined using an infra-red thermal sensor. The loss of moisture (% wet basis) from chickpea was correlated with the average surface temperature during microwave heating. A high positive correlation was observed (0.9) between the two parameters. Weighed amount of chickpea sample (50 g) was placed inside the microwave and treated at 0, 160, 320, 480, 640 and 800 W for 10 to 50s with 10 seconds of regular intervals. A temperature gradient was observed with each microwave treatment combination i.e. a non-uniform temperature distribution resulting into hot and cold regions within the treated sample. Results confirmed that power level and treatment time has a significant effect on the average surface temperature development (p<0.05). The study results proved that the temperature variation must be taken into consideration while designing any microwave system and the selection of microwave parameters (power level and treatment time) during experiments involving legumes.

Keywords

Microwave, power level, temperature profile, chickpea, surface temperature

Conclusion

The present study has demonstrated a significant temperature disparity in chickpea seeds during microwave treatment. The temperature variation is observed at all power levels and treatment times. However, the temperature difference is more pronounced at higher power levels and treatment durations than at lower levels. This increase in temperature is attributed to the elevated dielectric constant of chickpeas at higher temperatures. This variation can be minimized but not entirely eliminated. The loss in moisture content remains negligible up to 40 seconds of treatment with less than 1% loss at all power levels. Non uniform temperature distribution is because at some point temperature increased to very high and at some points temperature was significantly lower. Therefore, it is suggested that caution should be exercised with respect to the maximum temperature development during grain processing. This is because the quality of the grain may be compromised due to the elevated temperatures at certain locations, even if the average temperature falls within an acceptable range.

References

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How to cite this article

Shaghaf Kaukab, Abhijit Kar, Shiva Dhar, Alka Mishra, Subramanian S. and Baidya Nath Mandal (2023). Chickpea Temperature Profile Development and its Implication under Microwave Treatment. Biological Forum – An International Journal, 15(10): 648-653.