Effect of Novel High-Intensity Ultrasound Technique on Physio-Chemical, Sensory Attributes, and Microstructure of Bovine Semitendinosus Muscle.

The present study aimed to evaluate the effects of high-intensity ultrasound (HIU) application on meat quality traits, sensory parameters, and the microstructure of semitendinosus muscle from Hanwoo cattle. The samples were treated in an ultrasonic bath (35 kHz) at an intensity of 800 W/cm2 for 60 min, followed by aging at 1°C for 0, 3, and 7 days. The application of ultrasound resulted in lower Warner-Bratzler shear force and higher myofibrillar fragmentation index values during the storage period. HIU also enhanced the tenderness, flavor, umami, and overall acceptability of cooked beef muscle. However, the electronic tongue evaluation results showed higher umami values in the control treatment on the seventh day of storage. The microstructure of sonicated meat showed disorganized myofibrillar architecture and swelling in the A-band region of sarcomeres during the storage period, which led to greater meat tenderness. The heatmap illustrated the high abundance of α-linolenic acid (C20:5n3) and eicosapentaenoic acid (C18:3n3) in sonicated meat samples on the third day of the storage. These results showed that HIU is a potential method for tenderizing and improving the sensory attributes of beef without compromising other quality aspects.

Effects of lysine concentration of the diet on growth performance and meat quality in finishing pigs with high slaughter weights.

The present study aimed to investigate the feasibility of using a diet low in lysine content as a means for increasing the intramuscular fat (IMF) content and pork muscle quality of finishing pigs. Thirty-two crossbred gilts and barrows weighing approximately 80 kg were fed either a low-lysine diet (0.60%; Low-lys) or a control diet (0.80% lysine; Med-lys) under a 2 × 2 factorial arrangement of treatments. The animals were slaughtered at a 132-kg body weight (BW) on average, followed by physicochemical analyses and sensory evaluation on Longissimus lumborum (LL) and Semitendinosus (ST) muscles. The average daily gain (ADG) did not differ between the Med-lys and Low-lys groups. However, ADG exhibited a tendency of sex × diet interaction (p = 0.09), being greater for barrows vs. gilts on the Low-lys diet (p < 0.05), but not on the Med-lys diet. Backfat thickness adjusted for 132-kg BW also exhibited the interaction; it was greater for the Low-lys vs. Med-lys group within gilts but tended to be less for the former in barrows (p = 0.08). The IMF content was not influenced by the diet or sex in either LL or ST. The a*, b*, and Warner-Bratzler Shear Force values and fatty acid composition were influenced by the sex or diet in either or both of the muscles, but the treatment effects did not apparently influence the meat quality. Sensory scores for the flavor, juiciness, tenderness, umami, and palatability of cooked muscle were not influenced by the diet in either LL or ST. When the LL and ST data were pooled, scores for those sensory attributes were positively correlated with the IMF content, which was associated with overall greater IMF contents and greater sensory scores for ST vs. LL. Collectively, the Low-lysine diet seemingly elicited the intended lysine deficiency in gilts as indicated by the increased BFT due to the diet. However, the Low-lys diet was not effective for increasing the IMF deposition or eating quality of the pork muscle of finishing pigs slaughtered at high BW probably because its lysine content was not low enough to elicit either outcome.

Aging mechanism for improving the tenderness and taste characteristics of meat.

Tenderness and taste characteristics of meat are the key determinants of the meat choices of consumers. This review summarizes the contemporary research on the molecular mechanisms by which postmortem aging of meat improves the tenderness and taste characteristics. The fundamental mechanism by which postmortem aging improves the tenderness of meat involves the operation of the calpain system due to apoptosis, resulting in proteolytic enzyme-induced degradation of cytoskeletal myofibrillar proteins. The improvement of taste characteristics by postmortem aging is mainly explained by the increase in the content of taste-related peptides, free amino acids, and nucleotides produced by increased hydrolysis activity. This review improves our understanding of the published research on tenderness and taste characteristics of meat and provides insights to improve these attributes of meat through postmortem aging.

Optimal Pre-Plating Method of Chicken Satellite Cells for Cultured Meat Production.

To establish a pre-plating method of chicken satellite cells with high purity, pre-plating was performed under culture conditions of 37°C and 41°C, and the pre-plating time was set from a total of 3 hours to 6 hours in consideration of the cell attachment time. The purity of the cells was confirmed by staining paired box protein 7 (Pax7) after proliferation, and Pax7 expression was the highest in culture flasks shaken for 2 hours after incubation at 41°C for 2 hours to prevent the attachment of satellite cells (p<0.05). Also, when pre-plating and proliferation were performed at 37°C and 41°C, the Pax7 expression rate was higher at 41°C. The differentiation capabilities of the three groups (T3, T6, and T7) with high Pax7 expression were compared and the fusion index (%) and myotube formation area (%) determined by myosin heavy chain (MHC) staining was calculated. The T6 and T7 groups, which were cultured at 41°C, showed significantly higher values than the T3 group (p<0.05). There was no significant difference in the expression of Pax7 and MHC between the T6 and T7 groups (p>0.05). These results suggest that pre-plating at 41°C for a total of 4 hours was the most efficient in terms of cost and time for purifying chicken satellite cells for cultured meat.

Influence of Zika virus 3'-end sequence and nonstructural protein evolution on the viral replication competence and virulence.

Zika virus (ZIKV) has been circulating in human networks over 70 years since its first appearance in Africa, yet little is known about whether the viral 3'-terminal sequence and nonstructural (NS) protein diverged genetically from ancient ZIKV have different effects on viral replication and virulence in currently prevailing Asian lineage ZIKV. Here we show, by a reverse genetics approach using an infectious cDNA clone for a consensus sequence (Con1) of ZIKV, which represents Asian ZIKV strains, and another clone derived from the MR766 strain isolated in Uganda, Africa in 1947, that the 3'-end sequence -UUUCU-3' homogeneously present in MR766 genome and the -GUCU-3' sequence strictly conserved in Asian ZIKV isolates are functionally equivalent in viral replication and gene expression. By gene swapping experiments using the two infectious cDNA clones, we show that the NS1-5 proteins of MR766 enhance replication competence of ZIKV Con1. The Con1, which was less virulent than MR766, acquired severe bilateral hindlimb paralysis when its NS1-5 genes were replaced by the counterparts of MR766 in type I interferon receptor (IFNAR1)-deficient A129 mice. Moreover, MR766 NS5 RNA-dependent RNA polymerase (RdRp) alone also rendered the Con1 virulent, despite there being no difference in RdRp activity between MR766 and Con1 NS5 proteins. By contrast, the Con1 derivatives expressing MR766 Nsps, like Con1, did not develop severe disease in wild-type mice treated with an IFNAR1 blocking antibody. Together, our findings uncover an unprecedented role for ZIKV NS proteins in determining viral pathogenicity in immunocompromised hosts.

Quality Characteristics of Meat Analogs through the Incorporation of Textured Vegetable Protein: A Systematic Review.

Meat analogs produced through extruded products, such as texture vegetable protein (TVP) with the addition of various plant-based ingredients are considered the products that have great potential for replacing real meat. This systematic review was conducted to summarize the evidence of the incorporation of TVP on the quality characteristics of meat analogs. Extensive literature exploration was conducted up to March 2022 for retrieving studies on the current topic in both PubMed and Scopus databases. A total of 28 articles published from 2001 to 2022 were included in the data set based on specific inclusion criteria. It appears that soy protein is by far the most used extender in meat analogs due to its low cost, availability, and several beneficial health aspects. In addition, the studies included in this review were mainly conducted in countries, such as Korea, the USA, and China. Regarding quality characteristics, textural parameters were the most assessed in the studies followed by physicochemical properties, and sensory and taste attributes. Other aspects, such as the development of TVP, the difference in quality characteristics of texturized proteins, and the usage of binding agents in various meat analogs formulations are also highlighted in detail.