Characterization of thermal effects and optimization in laser drying process of pepper berries (<i>Piper nigrum</i> L.): A feasibility study

Conventional drying methods use comparatively high temperatures for prolonged periods of time, hence lowering the final product quality and changing consumer preferences. Laser drying is a reasonably effective drying technique that has advantages over traditional drying techniques. Pepper berries were dried by laser dryer at different drying conditions and the morphology, structural characterization, and thermal characteristics of laser-processed berries were studied. The process conditions for laser drying of pepper berries were optimized by using the Box-Behnken design of response surface methodology. The interaction of the independent variables including laser power, laser speed, and number of laser passes with the dependent variable which is the heat-affected zone was determined. It was observed that the laser speed had a notable influence on heat heat-affected zone. The optimized drying parameters were laser power of 0.81 W, laser speed of 9.4 mm/s, and five laser passes. At these optimum conditions, the predicted heat-affected zone was found to be 1495.08 μm. A validation experiment was conducted at optimum conditions to ensure the suitability of the model.