Impact of the power density on the physical properties, starch structure, and acceptability of oil-free potato chips dehydrated by microwave vacuum drying

Abstract

Oil-free potato chips with a preserved semicrystalline starch structure are an excellent carbohydrate source since they are related to a low-glycemic index. Microwave vacuum drying is an alternative to produce crispy products under mild temperatures, showing potential to reduce starch gelatinization, preserving its structure. However, the drying parameters require investigation once microwave power density can influence drying kinetics and product's physical properties, including starch structure. Thus, this study aimed to evaluate the impact of power density on the properties above and the product's sensory acceptance. Fresh potatoes were sliced and dried using three initial nominal power densities (6, 4, and 3 W/g) in a microwave vacuum oven with a rotatory system to guarantee uniform heating. The process temperature was controlled by microwave power modulation to avoid high temperatures that cause starch gelatinization. All the investigated conditions preserved the starch crystallinity, but the preservation was higher in the lower power density. However, the highest power density process produced dried samples in a shorter time with a more expanded and porous structure and crispier texture, leading to higher product acceptance. The resulting potato chips can address health and sensory concerns, essential to the world market that demands healthy and tasty foods.