Effect of microwave disinfection on the nutritional value, microbiological characteristics and thermophysical properties

BACKGROUND: Microwave disinfestation technique is potentially very suitable for postharvest treatment to control pests on food crops.

AIM: The purpose of this work is to study the process of disinfection of chickpeas using microwave technology and to assess its effect on nutritional value, microbiological parameters and thermophysical properties of the product.

METHODS: The samples of chickpea supplied from the ware houses of Pyin Oo Lwin were used for disinfestation. Physicochemical composition (nutritional value) of representative samples was also determined before and after treatment at Food Nutrition Analysis Laboratory. Furthermore, calculating the thermo-physical properties (specific heat) was performed to achieve a good thermal effect on food product. The samples were exposed with microwave energy levels 3 kW in different times of 60 s, and 80 s at 80 °C. The optimized as well as suitable exposure time of 80 s was chosen for the storage period, 12 months. The microbial population (yeast and mould) in food product was also determined during storage intervals.

RESULTS: Calculating equation for mass product production was developed dependent on heat transfer equation to know the definitely volume (mass) of food product. The amount of volume (mass) of chickpea required for experimental research was calculated. From these observed results, it was found that physicochemical composition of control and treated samples occurred no significantly changes due to microwave radiation effect on the samples. Initial total fungal count of chickpea is 2.0 × 10³ cfu/g, after 12 months: control — 70, treated 60 s —10, treated 80 s — 4 × 10³ cfu/g.

CONCLUSION: It was found that the application of microwave energy levels 3kW in 80 second at 80 °C would improve the hygienic quality and extend shelf-life of food (chickpea) sample.