Development of healthy crispy carrot snacks using sequential infrared blanching and hot air drying method

Sequential infrared (IR) blanching and hot air (HA) drying is a sustainable technology with high processing and energy efficiency. To develop a healthy crispy carrot snack, the carrot slices were blanched with IR at different intensities followed by HA drying at different temperatures. The results showed that IR blanching reduced the drying time at 60, 70 and 80 °C by 32.3%, 41.1% and 45.0%, respectively, and produced redder and crispier products with less residual peroxidase (POD) activity, compared to the treatments without blanching. In addition, the sequential IR blanched and HA dried carrot chips had 14.39%, 19.66% and 19.03% higher vitamin C contents than unblanched HA dried chips at 60 °C, 70 °C and 80 °C, respectively. IR blanching resulted in lower total carotenoid loss of the dried carrot samples. The optimal conditions for drying carrot chips were IR heating at 552 W power for 110 s by placing the samples at 70 mm from the emitter, for IR blanching, followed by HA drying at 80 °C for 45 min. In summary, sequential IR blanching and HA drying has a potential application in producing carrot snacks with improved sensory and nutritional quality.