Flavor variation during the processing of lotus root whole powder: a combination of hot air drying, lysine supplementation and baking

To investigate the dynamic changes in flavor characteristics of lotus root whole powder (LRWP) during combined hot-air drying and baking, and the effect of lysine supplementation before baking, volatile compounds and chemical constituents of samples representing different processing stages (raw, hot-air dried, hot-air dried and baked, and hot-air dried with lysine addition and baked) were analyzed using ultraviolet (UV) spectroscopy, electronic nose (<i>E</i>-nose), gas chromatography-ion mobility spectrometry (GC-IMS), and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Browning intermediates, browning degree, aroma components, and volatile compounds increased progressively with processing, especially during the baking stage. A total of 99 volatile compounds and 586 metabolites were identified, including 49 key volatiles and 345 differential metabolites. Lysine addition promoted the formation of specific volatiles (<i>e.g.</i>, 1-octen-3-one, (<i>Z</i>)-6-nonen-1-ol, 1-heptanol, linalool oxide) and amino acid-related metabolites, while reducing carbohydrate levels. These results provide insights for enhancing the flavor quality of dried and baked products.