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Thirty experimental Xuanwei hams were processed by a traditional method using green hams from local Xuanhe pigs of Xuanwei, Yunnan province, PR China. Samples of Biceps femoris were collected from six hams randomly at the five key processing stages, that is green ham, salting, air drying, aging for 3 months, and aging for 7 months. Physicochemical properties and water‐soluble small molecular (WSSM) compounds change during the processing period of Xuanwei ham were evaluated. Moisture contents, water activity, and total nitrogen contents (TN) decreased significantly (p <.05). On the contrary, chloride content, weight loss rate, non‐protein nitrogen content (NPN), and the protein hydrolysis index (P.I.) were observed a significant increase during the processing. The WSSM compounds in various processing stages of Xuanwei ham were analyzed by proton nuclear magnetic resonance (1H‐NMR) technology. A total of 54 WSSM compounds were found, consisting of 26 amino acids and their derivatives, 10 organic acids, 6 nucleic acids, 4 amines and ammonia compounds, 3 alcohols, 2 sugars, and 3 other WSSM compounds. After aging for 7 months, the content of free amino acids in hams reached 58.93 mg/g, and the main amino acids were glutamic acid and alanine. In this study, the physicochemical properties of Xuanwei ham were evaluated effectively, which provided the basis for the quality control of Xuanwei ham. Practical applications: Dry‐cured Xuanwei ham is a traditional fermented meat product in Yunnan province of southwest China. The aim of this study was to determine the changes in physicochemical properties and water‐soluble low molecular weight compounds of dry‐cured Xuanwei ham during the production process. Our findings thus provide a theoretical analysis on the quality changes of dry‐cured Chinese Xuanwei ham during processing. The results of this study can provide important theoretical basis for further study on protein degradation mechanism and characteristic flavor formation of Xuanwei ham. [ABSTRACT FROM AUTHOR]

• Fuel-N mainly released in the form of NO in O 2 /H 2 O combustion of demineralized char. • Increase of T r and O 2 concentration could inhibit NO emission in O 2 /H 2 O combustion. • C(O) amount reflected demineralized char reactivity and NO emission characteristics in combustion. • There was linear correlation between I (Gr+VL+Vr) /I D and demineralized char reactivity. Surface behavior and structural characteristics of char particles generally play a vital role in affecting char NO emission characteristics during combustion process. A typical bituminous Shenhua from northwest China was employed for demineralization in this research. The demineralized coal without catalytic interference of alkali metal salts was employed as the experimental sample. Moreover, by means of the utilization of isothermal combustion test, Temperature Programmed Desorption (TPD) and Raman spectrometer, the conversion ratio of nitrogen content in char to NO, as well as the evolution of char surface behavior and micro-structure in the process of O 2 /H 2 O combustion under different conditions were determined. With the increase of reaction temperature (T r) and O 2 concentration, more surface active sites (C f), oxygen containing functional groups (C(O)) and small aromatic ring structures generated on char particle surface inhibiting the emission of NO during O 2 /H 2 O combustion process. Under identical reaction conditions (Tr, O 2 and H 2 O concentration), the partially oxidized chars with moderate burnout degree (X c ≈ 0.3) had the largest amount of C f on particle surface. On the other hand, the amount of C f and small aromatic ring structures first increased and then decreased as the H 2 O concentration enhanced. When the C f amount and the value of I (Gr+VL+Vr) /I D reached the maximum at the H 2 O concentration of approximately 8.5 vol%, the conversion ratio of char-N to NO reached the minimum value. Meanwhile, the increase of H 2 O concentration initially accelerated the NO reduction rate and this positive effects gradually diminished when the H 2 O concentration exceeded the critical value (8.5 vol%). Thus, the optimal combustion condition for char combustion with the lowest NO conversion ratio in this study was: 1473 K, 30% O 2 and 8.5 vol% H 2 O. [ABSTRACT FROM AUTHOR]