Different actions of salt and pyrophosphate on protein extraction from myofibrils reveal the mechanism controlling myosin dissociation

l-arginine and l-lysine supplementation to NaCl tenderizes porcine meat by promoting myosin extraction and actomyosin dissociation

This study investigated the individual and combined effects of l-arginine, l-lysine, and NaCl on the ultrastructure of porcine myofibrils to uncover the mechanism underlying meat tenderization. Arg or Lys alone shortened A-bands and damaged M-lines, while NaCl alone destroyed M- and Z-lines. Overall, Arg and Lys cooperated with NaCl to destroy the myofibrillar ultrastructure. Moreover, these two amino acids conjoined with NaCl to increase myosin solubility, actin band intensity, and the protein concentration of the actomyosin supernatant. However, they decreased the turbidity and particle size of both myosin and actomyosin solutions, and the remaining activities of Ca2+- and Mg2+-ATPase. The current results revealed that Arg/Lys combined with NaCl to extract myosin and dissociate actomyosin, thereby aggravating the destruction of the myofibrillar ultrastructure. The present results provide a good explanation for the previous phenomenon that Arg and Lys cooperated with NaCl to improve meat tenderness.

Monitoring of polyphosphate levels in animal source products collected in Italy by means of ion chromatography with suppressed conductivity detection

Polyphosphates (PPs) constitute a class of food additives widely used due to their ability to exercise different useful activities. The food safety concern about the use of PPs in food is both the possible non-declared addition and some health effects, such as bile duct stones, decrease in oligo-element absorption, and allergic reactions in susceptible people. In this study, an analytical method based on ion chromatography with conductivity detection was applied for the detection and quantification of PPs in 238 samples of animal-derived products such as meat, dairy, and fish products. A contribution to risk assessment was also included. The monitoring confirmed the absence of non-compliant results. All concentrations of PPs were indeed lower than the legal limits set in European Regulation No. 1333/2008. Moreover, no residue of PPs was detected (> limit of quantification: 0.09 g kg-1) in samples where it was not reported on the product label. No PPs were detected in mollusks, meat-based preparations, semi-ripened, unripened, and spun paste cheese, while they are widely used in surimi, with concentrations in the range of 0.1-0.5 g kg-1. The highest concentrations were quantified in a würstel sample (4.7±0.3 g kg-1) and a spreadable cheese sample (8.9±0.7 g kg-1). Considering that the high exposure scenario together with a very susceptible population group (toddlers) were taken into account for this risk exposure study and that the highest admissible daily intake obtained was equal to 10.4%, the assessment demonstrated that the actual use of PPs in food does not pose a risk for food safety.

Advances in application of ultrasound in meat tenderization: A review

Tenderness could measure the eating quality of meat. The mechanism of muscle tenderization is becoming more and more critical in the past decade. Since the transforming of muscle into edible meat requires a complex physiological and biochemical process, the related tenderization of meat can be beneficial to improving the meat quality. As a non-thermal processing technology with energy-saving, environmental protection, and intense penetration, ultrasonic treatment has been widely used in the tenderizing process of meat products. In this paper, the principle of meat tenderization, the ultrasonic technology, and the application of ultrasonic technology in meat tenderization is summarized. The effect of ultrasonic technology on the tenderization of meat products is discussed from different perspectives (muscle fibers and connective tissue properties).

Characterization of silver carp myosin glycated with phosphorylated konjac oligo-glucomannan

BACKGROUND

Myosin (Ms) is abundant in fish meat, but it has limited application in the food industry because of its low solubility and thermal stability. Our previous reports found that these functional properties of Ms can be significantly improved after glycation with konjac oligo-glucomannan (KOG). However, the effects of phosphorylated KOG (PKOG) on physicochemical, structural and functional properties of silver carp Ms are still unknown.

RESULTS

This study characterized the silver carp Ms protein glycated with PKOG at 50 °C and 75% relative humidity for 48 h. As degree of phosphorylation increased, free amino content increased, whereas degree of grafting decreased. Meanwhile, isoelectric point (pI) reduced, however, PKOGs showed no differences in pI. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis suggested the formation of glycoconjugates, and scanning electron microscopy revealed thinner flakes and uneven appearance of glycoconjugates. Fourier transform infrared spectroscopy indicated that the amide I, II and III bands of Ms were changed by the glycation. Ms became highly soluble in 0.5 mol L^-1 NaCl with increased phosphate addition in PKOGs. Thermal stability of Ms was effectively improved when heated at 80 °C for 60 min.

CONCLUSION

Glycation with appropriate PKOG might be a promising method for Ms modification because of the resulting improvement in solubility and thermal stability. © 2021 Society of Chemical Industry.

Techniques for postmortem tenderisation in meat processing: effectiveness, application and possible mechanisms

Abstract

Developing efficient and promising tenderising techniques for postmortem meat is a heavily researched topic among meat scientists as consumers are willing to pay more for guaranteed tender meat. However, emerging tenderising techniques are not broadly used in the meat industry and, to some degree, are controversial due to lack of theoretical support. Thus, understanding the mechanisms involved in postmortem tenderisation is essential. This article first provides an overview of the relationship of ageing tenderisation and calpain system, as well as proteomics applied to identify protein biomarkers characterizing tenderness. In general, the ageing tenderisation is mediated by multiple biochemical activities, and it can exhibit better palatability and commercial benefit by combining other interventions. The calpain system plays a key role in ageing tenderisation functions by rupturing myofibrils and regulating proteolysis, glycolysis, apoptosis and metabolic modification. Additionally, tenderising techniques from different aspects including exogenous enzymes, chemistry, physics and the combined methods are discussed in depth. Particularly, innovation of home cooking could be recommended to prepare relatively tender meat due to its convenience and ease of operation by consumers. Furthermore, the combined interventions provide better performance in controlled tenderness. Finally, future trends in developing new tenderising techniques, and applied consideration in the meat processing industry are proposed in order to improve meat quality with higher economical value.

Graphical abstract

Duck breast muscle proteins, free fatty acids and volatile compounds as affected by curing methods

The aim of this study was to investigate the effects of different curing methods on protein structure, protein and lipid oxidation, lypolysis and volatile compounds in duck breast meat. The results showed that compared to static brining and pulsed pressure salting, the vacuum tumbling curing significantly decreased the oxidation of proteins and lipids, and the surface hydrophobicity of proteins, increased α-helix structure but decreased the proportion of β-sheet, and increased actomyosin dissociation, liplysis and the free fatty acid content in meat. Meanwhile, vacuum tumbling curing decreased the amount of volatile flavor compounds, hexanal, 2,3-octanone, and off-flavor compounds 1-octen-3-ol and 1-hexanol. This study suggests that concerns on healthiness and the sensory quality of processed meat products should be paid in the selection of curing methods and vacuum tumbling curing is superior in terms of both aspects.

Potassium carbonate improves fresh pork quality characteristics

Meat enhancement strategies like sodium tripolyphosphate (STP) are used to improve fresh meat quality attributes like color, water-holding capacity, and tenderness. However, alternatives are necessary because of reduced consumer acceptance of STP. One alternative is potassium carbonate (K₂CO₃). A study was conducted to evaluate K₂CO₃'s impact on fresh, boneless, center-cut pork loins enhanced with one of five treatments: a negative control, positive control (0.3% STP), and three concentrations of K₂CO₃ (0.1, 0.3, and 0.5%). Loins were cut into chops, stored under simulated retail display, and analyzed for color (L*, a*, b*), pH, cook loss, and tenderness. For each quality characteristic measured, the 0.3% and 0.5% K₂CO₃ maintained redness (a*), decreased yellowness (b*), reduced cooking loss, and maintained tenderness compared to STP. SDS-PAGE analysis further determined that both K₂CO₃ and STP extracted myosin heavy chain. Combined, these data suggest that K₂CO₃ may function as an alternative to STP in the fresh pork industry provided microbial safety and shelf-life are appropriately controlled.

Effects of licury cake in young Nellore bull diets: salted sun-dried meat is preferred rather than fresh meat by consumers despite similar physicochemical characteristics

BACKGROUND

Salted Sun-dried meat is a traditional process of meat salting that can improve quality and overall acceptance. The present study compared the physicochemical and sensory attributes of fresh and salted sun-dried meat from Nellore Zebu (Bos taurus indicus) bulls (n = 32) and evaluated diets containing different levels (0%, 7%, 14% and 21%) of licury cake in diets provided to Nellore finished in a feedlot.

RESULTS

Salted sun-dried meat decreased moisture (P < 0.0001) and ether extract (P = 0.0002) contents but increased ash (P < 0.0001) and protein (P < 0.0001) contents compared to fresh meat. The addition of licury resulted in linear increases in moisture (P = 0.02) and quadratic effects on Warner-Bratzler shear force (P < 0.03) in fresh meat. Cooking weight loss (P < 0.0001) and Warner-Bratzler shear force (P = 0.03) were reduced by the manufacturing process of sun-dried meat. Sun-dried meat presented greater color index L^* (P = 0.0032), a^* (P < 0.0001) and c^* (P < 0.0001) values but a lower index color b^* (P < 0.0001) value compared to fresh meat. Salted sun-dried meat presented greater sensory characteristic scores compared to fresh meat (P > 0.05).

CONCLUSION

Licury cake can be used in 21% of dry matter in diets to finish animals in feedlot without lessening the quality fresh meat or sundried meat. Salted sun-dried meat presented a greater overall acceptance. © 2016 Society of Chemical Industry.