•Chondroitin sulfates from sturgeon skull and sturgeon backbone were characterized.•Sturgeon skull CS was primarily composed of nonsulfated disaccharide.•The two CSs both had anticoagulant, anti-platelet and thrombolysis activities.•Sturgeon backbone CS showed stronger antithrombotic effect than sturgeon skull CS.Chondroitin sulfates (CSs) were extracted from sturgeon skull and backbone, and their chemical composition, anticoagulant, anti-platelet and thrombolysis activities were evaluated. The average molecular weights of CS from sturgeon skull and backbone were 38.5 kDa and 49.2 kDa, respectively. Disaccharide analysis indicated that the sturgeon backbone CS was primarily composed of disaccharide monosulfated in position four of the GalNAc (37.8%) and disaccharide monosulfated in position six of the GalNAc (59.6%) while sturgeon skull CS was primarily composed of nonsulfated disaccharide (74.2%). Sturgeon backbone CS showed stronger antithrombotic effect than sturgeon skull CS. Sturgeon backbone CS could significantly prolong activated partial thromboplastin time (APTT) and thrombin time (TT), inhibited ADP-induced platelet aggregation and dissolved platelet plasma clots in vitro. The results suggested that sturgeon backbone CS can be explored as a functional food with antithrombotic function.

The aim of this research was to characterize the lamb M. longissimusdorsi (LD), M. semitendinosus (ST), and M. psoasmajor (PM) muscles for differences in instrumental colour, tissue oxygen consumption rate (OCR), mitochondrial respiration control ratio (RCR), metmyoglobin reductase activity (MRA), and the relative proportions of myoglobin (Mb) redox forms. LD, ST, and PM muscles were stored for 6 days at 4 °C. Changes in the instrumental colour (CIE L*-value, a*-value, b*-value, Chroma-value, and Hue-value), OCR, RCR, MRA, and relative proportions of Mb redox forms during storage were evaluated. LD revealed the lowest MetMb accumulation and highest colour stability. Muscles with higher colour stability had lower levels of OCR, higher MRA, and less MetMb accumulation. Colour stability and MRA for the lamb muscles were LD > ST > PM. The correlation coefficients among the main parameters were also investigated in this research. The correlation coefficients between a*-value and OxyMb within the same muscle were highly significant (r = 0.951, 0.974, 0.828; P < 0.05). MRA of the muscles was negatively correlated (r = −0.810, −0.942, −0.971, P < 0.05) with the relative percentage of MetMb. The results of the present study suggested that OCR, RCR and MRA contribute to variation in colour stability of different lamb muscles.

Silver carp processing by-product protein is usually discarded as an industrial solid waste. In this study the protein was recovered using a pH-shift method, after which seven commercial proteases were separately employed to prepare antioxidative hydrolysates. Among the hydrolysates, pepsin hydrolysates, which had the highest free radical-scavenging activity, were further separated into five peptide fractions, SCPH-I (>10 kDa), SCPH-II (5–10 kDa), SCPH-III (3–5 kDa), SCPH-IV (1–3 kDa), and SCPH-V (<1 kDa), by using ultrafiltration. The antioxidative properties of the peptide fractions were investigated, using a free radical-scavenging assay, by electron spin resonance. The results show that SCPH-V had the highest scavenging effects on DPPH (1,1-diphenyl-2-picrylhydrazyl), hydroxyl and superoxide anion radicals. SCPH-V had potent antioxidant activity in the prevention of the peroxidation of linoleic acid and alleviation of H2O2-induced oxidative stress in human intestinal epithelial caco-2 cells. The results indicated that the antioxidant capacity of silver carp by-product hydrolysates could be enhanced by ultrafiltration.Research highlights► Proteins was recovered from fish by-products, then was hydrolysed and fractionated. ► Antioxidant properties were investigated on free radicals using ESR spectroscopy. ► The peptide fraction (<1 kDa) significantly prevented the peroxidation of linoleic acid and alleviated oxidative stress in human intestinal epithelial cells.

Changes in adipose triglyceride lipase (ATGL) and hormone-sensitive lipases (HSL) in subcutaneous adipose tissue of Xuanwei ham at different ripening stages were studied. Green hams were salted for 40 d and then ripened in a ventilated chamber for 15 months.Adipose triglyceride lipase and HSL could be detected during the whole ripening period of Xuanwei ham, but their protein levels decreased as the ripening time increased. The decrease of lipase proteins could be attributed to the decrease in protein synthesis as ripening time progressed. The level of free fatty acids (FFAs) increased at the first stage but HSL protein remained constant indicating that HSL was more important than ATGL for adipose tissues lipolysis. The main FFAs produced during the ripening period of Xuanwei ham were oleic acid, linoleic acid and palmitic acid, suggesting that the triacylglycerols containing these three FFAs were preferential substrates for ATGL and HSL.

The effects of different fats on animal lipid metabolism were investigated in order to clarify the safety of cured meat. The physical effect of nitrite in the cured meat was also explored due to a increased concern of this compound as a food additive. Body weight, food intake, organ/body weight ratio and plasma lipid profiles were analyzed. Rats fed with cured meat fat did not show any differences in body weight and food intake, compared with the control, and no significant difference was observed among groups. However, lard-fed rats showed marked morphological alternations in aortic intima and liver tissue. The cured meat group did not show apparent morphological changes on aorta intima compared to the control. Rats that received lard diet had significantly elevated TC (2.27 ± 0.46 mmol/ml), higher LDL-C (0.78 ± 0.31 mmol/ml) but lower HDL-C (1.55 ± 0.14 mmol/ml). Lard-fed rats had elevated oxidized LDL in serum and MDA level in blood and liver. However, diets containing fresh fat (with/without added nitrite) or cured meat fat failed to show these detrimental effects.

Cathepsin B from silver carp muscle was purified to 263-fold by acid treatment, ammonium sulfate fractionation, followed by a series of chromatographic separations. The molecular mass of the purified enzyme was 29 kDa as determined by SDS-PAGE and immunoblotting. The purified enzyme was activated by dithiothreitol and cysteine while it was substantially inhibited by E-64, suggesting the purified enzyme belongs to the cysteine proteinase family. Optimal pH and temperature were 5.5 and 35 °C, respectively. The enzyme catalyzed the hydrolysis of Z-Arg-Arg-MCA with a parameter of Km (90 μM) and Kcat (20.3 s−1), but hardly hydrolyzed Arg-MCA. Analysis of surimi gel strength and microstructure showed that cathepsins B and L were capable of destroying the network structure of silver carp surimi gels, consequently causing gel softening. Cathepsin L might play an important role in the modori effect.

Fatty acid composition of neutral lipids (NLs), phospholipids (PLs) and free fatty acids (FFAs) from intramuscular fat (IMF), lipid oxidation and lipase activity in muscle Semimembranosus (SM) and msucle Biceps femoris (BF) of dry-cured Xuanwei ham during the 90-d salting stages were analysed. The salt content increased from 0.34 to 3.52% in BF and from 0.10 to 5.42% in SM during the 90 d salting stage, respectively. PLs of IMF in both BF and SM decreased 54.70% (P<0.001) and 34.64% (P<0.05), furthermore, the saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) of PLs in both muscles were hydrolysed almost isochronously. FFAs were increased from 0.46 g 100 g−1 lipids to 2.92 g 100 g−1 lipids in BF at the end of salting, which was lower than SM (from 1.29 g 100 g−1 lipids to 9.70 g 100 g−1 lipids). The activities of acid lipase, neutral lipase and acid phospholipase all remained active in the 90 d. The thiobarbituric acid reactive substances (TBARS) was slowly increased to 1.34 mg kg−1 muscle in BF and to 2.44 mg kg−1 muscle in SM during the salting stage. In conclusion, the controlled salting process prompted the hydrolysis of PLs of IMF notably and increased the lipid oxidation of muscles within some limits.

The aim of this study was to investigate the effect of developmental stage on lipids deposition, composition and oxidative stability of subcutaneous adipose tissue (SAT) and Longissimus dorsi muscle (LDM) in Guizhou mini-pig. Pigs were raised in the same condition, and SAT and LDM were sampled on 90 d, 180 d and 270 d. Lipids content decreased (P < 0.01) from 90 d to 180 d and increased (P < 0.01) from 180 d to 270 d in SAT and LDM. Neutral lipids in both tissues decreased (P < 0.01) from 90 d to 180 d and increased (P < 0.01) from 180 d to 270 d, while phospholipids content changed inversely during the three selected time points. Developmental times had great influence on fatty acids (FAs) composition of neutral lipids, phospholipids and free fatty acids (FFAs) except FAs composition of FFAs in SAT. Lipids oxidative stability in SAT and LDM both decreased between 90 d and 180 d (P < 0.05) and increased by 270 d (P < 0.05). In conclusion, due to the increased contents of unsaturated fatty acids and decreased oxidation stability, Guizhou or other mini-pigs slaughtered at an early age may have a negative effect on meat quality.