Effect of thermal treatment on the flavor quality of Chinese spicy cabbage

The sensory properties and quality of Chinese spicy cabbage (CSC) are constantly changing, because of the ongoing fermentation in the process of packaging, storage, and marketing. Thermal treatment of CSC could inhibit microbial activities and prolong the shelf life. However, the research concerning the influence of different temperature treatments on CSC flavor quality is limited. In this study, the lactic acid bacteria (LAB) counts, physicochemical characteristics, odor profiles and sensory evaluations of CSCs treated with 80 °C (80P), 100 °C (100P) and 200 °C (200P) were determined. It was shown that thermal treatment could effectively reduce the LAB counts, and also showed significant influence on physicochemical properties and sensory of CSC. Principal component analysis, heatmap analysis, and calculation of odor activity values (OAVs) were used to distinguish CSC with different thermal treatments. A total of 54 volatile compounds (VCs) were detected in all samples, and 23 VCs were considered as key aroma compounds. Sulfides possessed high OAVs and were recognized as the most important key aroma compounds to CSC imparted cabbage, garlic, and onion odors. After thermal treatment, the sulfides content in 80P, 100P, and 200P groups decreased by 9.52%, 25.07%, and 81.10%, respectively. Thermal treatment at 80 °C does not increase or generate new key aroma compounds. When the temperature reached 100 °C, the contents of most aldehydes, ketones, acids, esters, terpenes, nitriles, and furans increased significantly, so increased the complexity of the overall aroma. The reduction of most VCs after thermal treatment at 200 °C resulted in the faint flavor of 200P. In addition, new compounds linalool and decanal were detected in the 100P and 200P groups, contributing to sweet, fruity, floral, fat and waxy odors. (E)-2-Decenal, (E)-2-octen-1-ol and 1-octen-3-ol were also identified as the potential aroma markers responsible for the aroma differences in CSCs thermally treated at different temperatures.