Search

We monitored the production process of Xinjiang dry‐cured mutton ham, and recorded changes in physicochemical and sensory quality such as appearance, texture, and aroma using E‐nose, texture profile analysis (TPA), and gas chromatography‐mass spectrometer (GC‐MS). During dry‐cured mutton ham processing, the moisture content decreased from 76% to 34%, while the NaCl content increased from 0.18% to 9.85%. Lipid oxidation was observed throughout the processing of dry‐cured mutton ham. Moreover, the nitrite content rapidly declined and reaching a minimum value of 1.58 mg/kg. During processing, the hardness of ham increased and its texture becomes tight, the chewability and gumminess improved over time. The muscle appeared rosy red, and the surface fat gradually became yellowish. Notably, seven classes of volatile compounds were identified among which aldehydes were the highest. Correlation analysis revealed that unsaturated fatty acids have a significant contribution to the composition of volatile compounds. PCA and cluster analysis results showed that the separation trend of the overall aroma profile of the dry‐cured mutton ham is obvious at different processing times. The quality of dry‐cured mutton ham changed the most during fermentation which was the key process stage of quality stabilization and improvement in the processing of dry‐cured mutton ham. These results provide information regarding the changes in aroma and quality of dry‐cured mutton ham during processing and are important for promoting the industrial processing of dry‐cured mutton ham. Practical applications: This study monitored the quality changes during the production of Xinjiang dry‐cured mutton ham. These results provide a basis for improving the quality of dry‐cured mutton ham and are important for promoting the industrial production of dry‐cured mutton ham. Developing high‐quality dry‐cured mutton ham will have a positive effect on promoting the added value of the mutton processing industry. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of crude peptide extract (CPE) from mutton ham on the lipid and protein oxidation of mutton patties during storage. Color indices, texture, and microbiological and sensory properties were assessed. The results showed that CPE addition significantly reduced thiobarbituric acid‐reactive substance levels, carbonyl content, sulfhydryl content loss, and protein cross‐linking in mutton patties; moreover, CPE improved their color, texture, and microbiological stability. Sensory evaluation results showed that CPE significantly improved the color, flavor, juiciness, texture, and overall acceptability scores of the patties. Overall, CPE was suitable for the production of mutton patties with good organoleptic qualities. Practical applications: In China, mutton patties are one of the most popular fast and convenient meat products. They are, however, prone to quality deterioration during storage. To the best of our knowledge, few studies have explored the effect of CPE from mutton ham on the antioxidant properties and quality of mutton patties. Herein, we report that CPE significantly inhibits the lipid and protein oxidation of mutton patties during storage, thereby improving product quality. [ABSTRACT FROM AUTHOR]

BACKGROUND: Chinese mutton ham is a dry‐cured meat product with a long ripening time. The aim of this study was to identify and characterize antioxidant peptides from Chinese mutton ham. RESULTS: Mutton ham peptides (MHPs) were purified by gel filtration, anion exchange and reversed‐phase high‐performance liquid chromatography steps. The 2,2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt (ABTS) free radical scavenging capacity was used to guide the purification of MHPs. Three antioxidant peptides were identified by liquid chromatography with tandem mass spectrometry (LC–MS/MS) as Met‐Trp‐Thr‐Asp (MWTD), Ala‐Pro‐Tyr‐Met‐Met (APYMM) and Phe‐Trp‐Ile‐Ile‐Glu (FWIIE), with molecular weights 551.61, 611.76, and 706.84 Da, respectively. Among them, APYMM exhibited the highest ABTS radical scavenging activity. The three peptides had the ability to inhibit lipid oxidation and Fenton's reagent‐induced protein oxidation and DNA damage. After simulated gastrointestinal digestion, FWIIE and APYMM showed increased antioxidant activity, while MWTD showed decreased activity. CONCLUSION: Three novel peptides isolated from Chinese mutton ham had strong biological activity. Chinese mutton ham is potentially a functional food and an excellent source of natural antioxidants. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Mutton is widely consumed in China, European Mediterranean countries, and other regions around the world and is expected to gain popularity as an alternative to pork in dry‐cured hams. Changes in the physicochemical indices, volatile compounds, and endogenous enzyme activities during the processing of dry‐cured mutton ham were investigated. Eighty‐six volatile compounds were identified during the dry‐curing process, with aldehydes being dominant. Oxidation values increased significantly during dry‐curing and decreased during ripening (p < .05). The activities of lipolytic enzymes remained active throughout processing, although the activities of the enzymes decreased. Lipoxidase activity increased rapidly during the fermenting stage and then decreased gradually during ripening (p < .05). Superoxide dismutase activity increased throughout processing, whereas the catalase activity decreased. According to partial least square variable importance in projection analysis, 49 odor‐related compounds were selected from dry‐cured mutton ham as specific compounds which are related to lipid oxidation and endogenous enzyme activities. Heatmap shows that the volatile compounds were correlated with enzyme activity and the oxidation value of dry‐cured mutton ham during processing. Practical applications: Xinjiang dry‐cured mutton ham has an intense and a long‐lasting aroma. Understanding the mechanism of aroma formation related to lipid oxidation could help us to improve the product quality and optimize the duration of processing. Therefore, the present work identified the characteristic flavor compounds and provided the changing regularity of these compounds at various stages to facilitate the generation of them. [ABSTRACT FROM AUTHOR]

Changes in proteolysis, protein oxidation, flavor, color and texture in dry-cured mutton ham during storage for 0, 30, 60, 90, 120, 150 and 180 days are investigated in this study. Several meat parameters changed during storage. Myofibrillar and sarcoplasmic proteins were degraded at varying degrees and the surface hydrophobicity of proteins increased significantly during storage (p < 0.05). Unlike the carbonyl content which increased significantly (p < 0.05), the content of thiol decreased during storage (p < 0.05). Arginine and lysine varied most (p < 0.05) among 17 free amino acids. Among flavor compounds, aldehydes were the most abundant volatile compounds in dry-cured mutton ham during storage. The hardness, gumminess, chewiness and adhesiveness of dry-cured mutton ham significantly increased (p < 0.05), but the springiness and cohesiveness of the ham decreased. Moreover, L * (brightness), a * (redness) and b * (yellowness) decreased to varying degrees. Principal Component Analysis showed that most critical and significant changes occurred after 90 days of storage. [Display omitted] • Quality change and protein degradation during mutton ham storage were comprehensively analyzed. • The flavor, texture, and color changes greatly with the increase of storage time. • Protein changes and affects the quality of dry-cured mutton ham. • Most critical and significant changes occur during storing ham for 90 days. [ABSTRACT FROM AUTHOR]

• Lipidomics were used to identify lipid changes during the processing of mutton ham. • Lipids are first degraded and then oxidized during the processing of mutton ham. • The number and types of lipids change the most in the fermentation period. • Glycerophospholipid and sphingolipid metabolism are critical metabolic pathways. Six key stages in the processing of dry-cured muton ham were selected, and changes in the main lipid metabolites as well as the major pathways involved were identified using a lipidic metabolomics approach based on UPLC-MS-MS. In total, 581 lipid metabolites from 22 subclasses were identified, including 521 significantly differential lipids (p < 0.05, VIP > 1). Glycerolipids (GL) were the most abundant lipids, followed by glycerophospholipids (GP), fatty acyls (FA), and sphingolipids (SL). PCA and OPLS-DA of metabolites showed that the quality of mutton ham changed the most during the P3 fermenting stage, including TG(18:1/18:2/18:3), PE(20:5/18:1), and TG(16:1/18:1/18:4) that were significantly downregulated, and CE(20:3), FFA(24:6), LPC(20:3/0:0), and FFA(18:4) that were significantly upregulated. Moreover, glycerophospholipid metabolism and sphingolipid metabolism were the key metabolic pathways involved in the processing of dry-cured mutton ham. Our results provide a basis for quality control and product improvement of dry-cured mutton ham. [ABSTRACT FROM AUTHOR]

[Display omitted] • The crude peptides extracted from the three types of ham have antioxidant activity. • UPLC-Q-TOF-MS/MS was used for peptide composition analysis. • The peptides in the three types of ham were mainly derived from myosin. The aim of the study was to evaluate antioxidant activity of crude peptides with molecular weight less than 3 KDa extracted from Xuanwei ham, Jinhua ham and mutton ham. UPLC-Q-TOF-MS/MS was used for composition analysis of peptides and homologous protein matching. Further, crude peptide (<3 KDa) was purified using G-15 gel filtration chromatography, and the main antioxidant peptide identified. Analysis showed that mutton ham peptide (MHP) has the highest Fe2+ chelating ability, whereas Jinhua ham peptide (JHP) had the highest ABTS and DPPH free radical scavenging ability (P < 0.05). A total of 346, 203 and 296 peptides were identified in JHP, Xuanwei ham peptides (XHP) and MHP, respectively. Most of the peptides were derived from myosin, accounting for 21.97% in JHP, 18.72% in XHP, and 21.96% in MHP. Myosin, actin, myoglobin, troponin, tropomyosin and pyruvate kinase proteins were the main source of peptide differences in the three types of dry cured ham. [ABSTRACT FROM AUTHOR]