Comparative analysis of drying characteristics, physicochemical properties and volatile flavor components of Dendrocalamus brandisii shoots under four drying techniques

Abstract

This study compared the differences in drying characteristics, physicochemical properties, and flavor composition of Dendrocalamus brandisii shoots (DBS) under four drying techniques: sun drying (SD), hot air drying (HAD), heat pump drying (HPD), and vacuum freeze-drying (VFD). The results show that Logarithmic model is the best choice for predicting DBS drying process. The color of VFD and HPD samples was closest to that of fresh samples, the texture properties of VFD and HPD were closest; Compared with HAD, SD and HPD, VFD exhibited loose and porous structure, good rehydration, and little destruction of nutrients, but HPD was closer to VFD. The chemical structure and microstructure of DBS dried using different techniques exhibit obvious differences. A total of 111 volatile organic compounds (VOCs) were identified by HS-SPME-GC-MS, of which 20 were identified as characteristic VOCs, and 8 were the key reasons for the flavor differences of DBS samples, among which the special pyrazine compounds in HPD and HAD samples gave them unique flavor, and HPD has the lowest energy and time consumption. In summary, considering the characteristics of bamboo shoots, energy consumption, drying rate and product quality, HPD is the best method for bamboo shoot drying.