Innovative green technology: Pulse cycle vacuum drying with carbon crystal heating poised to supplant conventional vacuum drying methods

Abstract

Drying plays a crucial role in ensuring global food security by reducing the moisture content to ensure safe storage of agri-food products. This study aims to develop a carbon crystal heating - pulsed cycle vacuum drying (CH-PVD) equipment and improve its performance using alternating vacuum - normal pressure patterns and Carbon crystal infrared plates. The developed dryer was used to dehydrate garlic at 60–75 °C and compared with vacuum drying (VD) and vacuum freeze drying (VFD). At 65 °C, compared with VD, the developed dryer reduced drying time and carbon footprint by 32.55 % and 41.56 % respectively, enhanced energy efficiency by 68.10 %. The quality of the dried garlic slices obtained by CH-PVD was better than that of VD while it was worse than that obtained with VFD. However, the rehydration ratio of the dried garlic slices obtained by CH-PVD was 89.84 % higher than that of VFD. The energy analysis of the three dryers revealed that the vacuum pump was the most energy consuming component in CH-PVD and VD, while the cooling unit was the most energy consuming component in VFD. At the same drying temperature, heating in VD accounted for 48.30 % of the total energy consumption, while heating in CH-PVD accounted for only 5.02 %. Compared with VD and VFD, CH-PVD could effectively reduce greenhouse gas emissions and had a shorter simple payback period (0.38–0.81 years). Based on the results of this study, it can be concluded that the CH-PVD is a promising drying technology for potential application in the food industry.