Oxidative characteristics and gel properties of porcine myofibrillar proteins affected by l‐lysine and l‐histidine in a dose‐dependent manner at a low and high salt concentration

Abstract

Summary This study investigated the effects of l‐lysine (Lys) and l‐histidine (His) on the oxidative characteristics and gel properties of porcine myofibrillar proteins (MP). Results showed that Lys and His had a strong ferrous ion‐chelating ability and hydroxyl radical‐scavenging activity. Moreover, Lys and His inhibited the protein carbonyl formation and MP aggregation at 0.2 M and 0.6 M NaCl, respectively, in a dose‐dependent manner. Furthermore, 2 and 4 mg mL−1 Lys and His decreased the oxidation‐induced loss of the tertiary structure of MP accompanied by the lower surface hydrophobicity. The water‐holding capacity and gel strength of MP gels increased with increasing Lys and His concentrations due to more regular and lamellar structures with smaller and homogeneous pores at 0.6 M NaCl and more orderly crosslinking via fibrous filament at 0.2 M NaCl. In summary, Lys and His chelated the ferrous ions and scavenged hydroxyl radicals, decreased the oxidation‐induced physicochemical changes, thus preventing oxidative damage during the formation of a three‐dimensional gel network, which resulted in better gel quality.

Dose-Dependent Effect of Hyperoside on the Physicochemical and Gel Properties of Porcine Myofibrillar Proteins at Different NaCl Concentrations under Oxidative Stress

“…In contrast, the oxidized MPs gel at 0.6 M NaCl showed a loose lamellar structure with more and larger pores, suggesting that oxidation induced the destruction of gel structure. This is consistent with the research of Guo et al [ 17 ], which showed that the gel structure of an oxidized MPs gel at 0.6 M NaCl was rough and cracked.…”

“…The surface hydrophobicity of MPs may reflect the extent of unfolding of MPs and is a considerable molecular characteristic associated with MPs functionality [ 17 ]. The effects of HYP on the surface hydrophobicity of the samples were examined ( Figure 1 ).…”

“…Oxidation caused a significant decrease in gel strength ( p < 0.05), which might be result from the loss of SH content. The reduction of sulfhydryl groups might lead to a decrease in disulfide bond formation during heating, thus reducing the interactions between MPs and MPs and preventing the formation of a fine three-dimensional gel network [ 17 ]. Upon oxidation, an obvious increase in gel strength was shown with the increment in NaCl concentration ( p < 0.05).…”

“…MPs were prepared in accordance our previous study [ 17 ]. Briefly, 100 g of pork was homogenized with 400 mL extracting solution containing 10 mM ethylenediamine tetraacetic acid (EDTA) and 100 mM Tris (pH 8.3) using a blender (Midea, Foshan, Guangdong, China).…”

“…Images of the samples were acquired through cryo-SEM (Hitachi SU8010, Quorum PP3010T, TKY, JPN) on the basis of the method described in the study of Guo et al [ 17 ]. Gels were prepared for cryo-SEM by sectioning a small sample (2 mm × 2 mm × 5 mm) and mounting it in a cylindrical plug of a copper sample holder such that a portion of the specimen protruded above the face of the holder to facilitate freeze fracture.…”