The chemical, sensory, and volatile characteristics of instant sweet tea (Lithocarpus litseifolius [Hance] Chun) using electronic nose and GC-MS-based metabolomics analysis

This study aims to investigate the effect of instant tea processing on the chemical, sensory, and volatile profiles of sweet tea. Young leaves of Lithocarpus litseifolius [Hance] Chun were extracted and dried with freeze-drying and spray-drying, respectively. The contents of proteins, polysaccharides, total phenolics, total flavonoids, and free amino acids in instant teas were found to be higher than those in sweet tea. A total of 268 volatiles were identified by HS-SPME-GC-MS, and 88 compounds showed significant differences among different samples, and most of volatile compounds showed lower concentrations in instant tea powder than sweet tea powder. Nine aroma attributes were evaluated through descriptive sensory analysis. Sweet tea had a higher intensity of woody, green, floral, fruity, and sweet descriptor, while the instant sweet teas demonstrated the higher intensity of caramel-like attribute. Our study emphasized the nutritive value of instant sweet tea, while the aroma needs to be improved further.