Optimization of Vacuum Frying of Carrot Chips Using Response Surface Methodology

Abstract

Vacuum frying presents a promising low-temperature alternative to conventional frying, yielding fried snacks with substantially lower oil uptake, reduced formation of harmful compounds (e.g., acrylamide) and better retention of nutrients. Carrots (Daucus carota L.) are rich in β-carotene, vitamins, dietary fiber, and polyphenols that support human health. To harness these benefits in a crispy snack, we optimized the vacuum frying process for carrot chips using central composite RSM. Carrot strips were fried under vacuum at combinations of oil temperature (100°C–120°C), pressure (11–15 kPa) and time (16–20 min). The effects on key quality attributes such as moisture content, water activity, oil uptake, texture, color, and sensory quality were modeled. Regression models (R² ≥ 0.94) were obtained for each response. Results showed increasing frying temperature and time significantly reduced moisture and water activity while increasing oil content and hardness. Notably, optimal frying at 100°C, 11 kPa for 16 min produced chips with ~0.38% moisture, 11.3% oil, and 60% thickness expansion, with acceptable color and crispness. Vacuum fried carrots retained high levels of carotenoids and exhibited < 10% oil content, echoing previous findings of minimal nutrient loss and ~94% acrylamide reduction under vacuum. The study demonstrates RSM's utility in predicting and balancing vacuum frying variables to produce high-quality carrot snacks. These results underscore vacuum frying's potential for healthier fried products, combining desirable sensory attributes with lower fat and harmful byproducts.