Effects of different drying methods on the quality characteristics of Morchella

This study aims to determine the most suitable drying for Qinghai Morchella. Fiver drying methods were selected as hot air drying (HAD) at different temperatures (45 , 50 , 55 ℃), carbon fiber far-infrared drying (CFFD), heat pump drying (HPD), carbon fiber far-infrared combined heat pump drying (CFFD-HPD), and vacuum pulse drying (VPD). A comprehensive evaluation was also performed on the drying time, drying energy consumption, color, quality (rehydration ratio, texture characteristics, e-nose electronic tongue, sensory evaluation), and nutritional indicators (amino acids, protein, crude polysaccharides, fat content) of Morchella. The research results showed that the drying time of the CFFD-HPD group was the shortest with no significant difference, compared with the HAD (55 ℃) group (P>0.05). But there was a significant difference from other groups (P˂0.05). The drying time and energy consumption of the VPD group were the highest, significantly higher than those of the rest (P˂0.05). In terms of appearance quality, the L* value of HAD (50 ℃) was higher than that of the rest (P˂0.05), whereas, the L* value of the VPD group was lower (P˂0.05), and a* was higher (P˂0.05). The Morchella shared a darker color, and redness. The highest energy was also found with a significant degree of contraction in a collapsed state. In terms of sensory quality, there was a significant difference in the rehydration ratio of Morchella under different drying methods (P˂0.05). The CFFD and VPD groups showed the highest and lowest final rehydration ratio of Morchella at the same drying temperature, respectively. After 20min rehydration, the CFFD-HPD group had the highest rehydration rate of Morchella, and the CFFD group was the lowest, the HAD (45 ℃) group had the highest hardness and viscosity, the HAD (55 ℃) group had the highest elasticity and chewiness, and the VPD group had the lowest hardness and chewiness. Sensory evaluation of dried morel showed that HAD and CFFD-HPD groups had the higher scores, while VPD had the lowest sensory evaluation score. In terms of nutritional quality, the electronic tongue measurement was highly correlated with different amino acid content. The amino acid content was indirectly determined in the different types of Morchella using electronic tongue measurement. The drying method had a significant impact on the nutritional quality of Morchella esculenta (P˂0.05). The polysaccharide content of Morchella in the HAD (55 ℃) group was significantly higher than that in other groups (P˂0.05), with the lowest fat content. The total amino acid and protein content of the VPD group were higher than the rest. The comprehensive evaluation score of CFFD-HPD was the highest, followed by HAD (55 ℃). The comprehensive evaluation score of VPD was the lowest, indicating that CFFD-HPD and HAD were suitable for drying Morchella. The finding can also provide the data support to introduce suitable drying techniques for Morchella.