Effect of sodium bicarbonate and varying concentrations of sodium chloride in brine on the liquid retention of fish (Pollachius virens L.) muscle

Myofibrillar proteins' intermolecular interaction weakening and degradation: Are they mainly responsible for the tenderization of meat containing l-arginine, l-lysine, or/and NaCl?

This study explored the effects of l-arginine, l-lysine, and NaCl alone and in combination on the tenderness of porcine meat. Arg, Lys, and NaCl alone improved the tenderness, decreased the cooking loss, and increased the myofibrillar fragmentation index (MFI) of porcine meat; Both Arg and Lys cooperated with NaCl to better achieve this effect. Furthermore, Arg/Lys collaborated with NaCl to increase muscle fiber swelling and moisture content of the meat and promoted the extraction of main myofibrillar proteins. FT-IR revealed that Arg, Lys, or NaCl alone or in combination caused changes in protein-water interactions. Western blotting revealed varying degrees of meat protein degradation in all cases, but the results did not well coincide with those of shear force and the MFI. Therefore, the weakening of intermolecular forces between myofibrillar proteins was considered the main reason for meat tenderization under the present study conditions.

Exercise training combined with a high-fat diet improves the flesh flavour, texture and nutrition of gibel carp (Carassius auratus gibelio)

To meet the consumer demand for high-quality flesh sources, this study investigated the impacts of exercise training (ET) combined with a high-fat diet (HFD) on flesh quality. The results showed that HFD increased muscular fat content but reduced hardness, flexibility and adhesiveness. ET decreased fat content but increased flesh water holding capacity, hardness and stickiness. In terms of flavour, ET decreased the umami and sweet amino acid contents, which were restored when concomitantly feeding the HFD. Metabolomics further revealed that ET and HFD mainly affect the alanine, aspartate and glutamate metabolism, the citrate cycle and purine metabolism. The E-nose and volatile metabolomics analysis demonstrated that the combination of ET and HFD improved the aroma of flesh by enhancing the content of key flavour compounds within flesh such as hexadecenoic acid, ethyl ester and methyl stearate. This research provides a new strategy for improving the flesh quality of cultured fish.

Effect of sodium bicarbonate on techno-functional and rheological properties of pale, soft, and exudative (PSE) meat batters

In the study, changes in salt-soluble protein (SSP) content, gel properties, rheological characteristic, and microstructure attributes of pale, soft, and exudative (PSE) pork batters with different concentrations of added sodium bicarbonate (0-0.6%) were investigated. The pH, b⁎ value, SSP content, cooking yield, texture properties, emulsion stability, and G' values at 72 °C significantly increased with the increase in sodium bicarbonate, but the texture properties and G' values of the samples with 0.4% and 0.6% did not significantly different, while the a⁎ value significantly decreased. Moreover, a greater G' value at 72 °C was in agreement with a higher hardness value of meat batter. The microstructure of cooked PSE meat batters with 0% and 0.2% sodium bicarbonate had a dense structure, and samples with 0.4% and 0.6% had some large cavities. In conclusion, the use of sodium bicarbonate can enhance the water holding capacity, texture and rheological properties of PSE meat batters by increasing their pH, SSP content, and emulsifying stability.

Rheological and water binding properties of xanthan, guar and ultra-finely milled oatmeal in white birch sap: Influence of sap minor constituents

White Birch Sap (WBS) contains appreciable amounts of mineral ions and phenolic compounds and can be used as alternate solvent for food applications. In this study, the effect of the mineral and phenolic composition of WBS was evaluated on the physical properties of xanthan gum, guar gum, ultra-finely milled oatmeal and their combinations in solution. Solutions were formulated with WBS and with solvents mimicking WBS without phenolic compounds and WBS without phenolics nor mineral ions. The influence of solvent composition was evaluated on flow properties and water mobility of the solutions. From WBS without mineral ions nor phenolics, the addition of mineral ions led to increased pseudo-plasticity and decreased flow consistency, and decreased water mobility. Addition of phenolic compounds through WBS led to opposite effects possibly due to phenolic-driven aggregation of the hydrocolloids which also seemed to inhibit guar/xanthan interactions.

Combined effect of ultrasound and sodium bicarbonate marination on chicken breast tenderness and its molecular mechanism

The objective of this study was to explore the combined effect of ultrasound (20 kHz ultrasound probe (12 mm diameter), an output power of 350 W for 5 min (on-time and off-time pulse durations of 2 s and 3 s, respectively)) with low concentration (0.2 M) sodium bicarbonate solution (USB) on chicken breast tenderness and its preliminary molecular mechanism. Therefore, myofibril fragmentation index (MFI), filtering residues, cooking loss, shear force, histology of meat as well as SDS-PAGE, circular dichroism (CD), synchronous fluorescence spectroscopy, differential scanning calorimetrv (DSC) of actomyosin were investigated and compared with untreated (Control), deionized water (DW), ultrasound in deionized water (UDW), 0.2 M sodium bicarbonate solution (SB), respectively. The results showed that USB can effectively increase MFI, and reduce filtering residues, cooking loss and shear force by compared with UDW or SB. Furthermore, myofibril was presented with the largest interfibrillary spaces and the highest degree of actomyosin dissociation in USB group. The increase in α-helix content and decrease in fluorescence intensity of tyrosine and tryptophan implied that USB caused the conformation change in actomyosin. Additionally, actomyosin in USB group became more sensitive to temperature. Therefore, the treatment of ultrasound combined with low concentration of sodium bicarbonate accelerated actomyosin degeneration was considered as a promising and efficient technique in meat processing, especially for the fitness enthusiasts.

Nutritive values, flavor amino acids, healthcare fatty acids and flesh quality improved by manganese referring to up-regulating the antioxidant capacity and signaling molecules TOR and Nrf2 in the muscle of fish

Flesh quality, amino acid and fatty acid composition, antioxidant status and related molecule expression in fish muscle were estimated by feeding grass carp with diets containing 3.65-27.86mg/kg diet of manganese (Mn) for 8weeks. Results demonstrated that optimal Mn increased toughness, collagen content, and pH, and decreased the cooking loss, and cathepsin B and L activities to enhance the flesh quality of fish. Meanwhile, optimal Mn increased the protein, lipid, the total essential amino acid (AA) (especially umami AA), and healthcare fatty acids, C18: 1c+t, C20: 3n-3, C20: 4 and DHA contents. These might be partially related to the decreased lipid peroxidation and protein oxidation, and the enhanced activities of Mn superoxide dismutase (MnSOD), catalase (CAT) and glutathione peroxidase (GPx) modulated by their gene expression, Nrf2 and TOR signaling. We firstly demonstrated that Mn improved flesh quality, flavor and healthcare function in fish muscle.