Effect of heat processing on the nutrient composition, colour, and volatile odour compounds of the long-horned grasshopper Ruspolia differens serville

•Heat processing doesn’t affect R. differens’ proximate, amino & fatty acids’ content.•Boiling & further roasting (165 °C, 45 min) increases its’ Ca, Cu, Fe, Mn & Zn content.•Boiling (100 °C, 30 min) reduces R. differens’ vitamin B12 content by 70–85%.•Heat processing increases the color uniformity between brown and green polymorphs.•Lipid oxidation is majorly responsible for heat-processed R. differens’ aroma & color.