Relative contribution of sensory characteristics for different types of pork loin, assessed by temporal dominance of sensations.

BACKGROUND: Sensory perception is a dynamic process occurring sequentially. The dynamic analysis of the perception of sensory characteristics in meat is important to understand complex meat sensory characteristics. Temporal dominance of sensations (TDS) is a dynamic sensory method that captures the 'dominance of sensations' throughout food consumption, and it is possible to calculate the relative contribution of various sensory characteristics by 'dominance rate' over time. The objective of this study was to assess the major sensory characteristics of the dynamic sensory perception of pork loin. Using the TDS, we evaluated pork loins derived from pigs with different genetic and feeding backgrounds. Moreover, we checked the integrity of the TDS by comparing the TDS results with a descriptive sensory analysis and a physico-chemical analysis. RESULTS: Seven types of pork loin were evaluated by TDS, and 'tender and/or soft,' 'tough and/or hard,' 'juicy,' 'dry,' 'fat melting,' 'smoothness,' 'sourness,' 'umami,' and 'beast odors' became dominant in at least one type of pork loin. The dynamics of the perception of pork sensory characteristics was also depicted by TDS. In addition, TDS and descriptive analysis demonstrated similarity in principal component analysis. CONCLUSION: TDS demonstrated the major sensory characteristics on the dynamic sensory perception of pork loin. © 2019 Society of Chemical Industry.

Relationship between water-holding capacity and intramuscular fat content in Japanese commercial pork loin.

OBJECTIVE: The relationship between water-holding capacity (WHC) and intermuscular fat (IMF) was studied in Japanese commercial pork. METHODS: Longissimus muscles of pigs (n = 62), obtained from two meat packing plants, were analyzed for IMF content, moisture content, drip loss, cooking loss, and pH. Pairwise relationships among these traits were determined using correlation analyses. RESULTS: IMF content was significantly correlated with moisture content (r = -0.88; p<0.01) and pH (r = 0.32; p<0.05), but not with drip loss (r = -0.23; p = 0.07) or cooking loss (r = -0.10; p = 0.42). In contrast, drip loss was significantly (and negatively) correlated with pH (r = -0.57; p<0.01). CONCLUSION: IMF content was not significantly correlated with WHC in pork, and so ultimately, we consider pH to be one of the most important factors influencing WHC in pork meat.

Classification and characterization of Japanese consumers' beef preferences by external preference mapping.

BACKGROUND: Over the past few decades, beef producers in Japan have improved marbling in their beef products. It was recently reported that marbling is not well correlated with palatability as rated by Japanese consumers. This study sought to identify the consumer segments in Japan that prefer sensory characteristics of beef other than high marbling. RESULTS: Three Wagyu beef, one Holstein beef and two lean imported beef longissimus samples were subjected to a descriptive sensory test, physicochemical analysis and a consumer (n = 307) preference test. According to consumer classification and external preference mapping, four consumer segments were identified as 'gradual high-fat likers', 'moderate-fat and distinctive taste likers', 'Wagyu likers' and 'distinctive texture likers'. Although the major trend of Japanese consumers' beef preference was 'marbling liking', 16.9% of the consumers preferred beef samples that had moderate marbling and distinctive taste. The consumers' attitudes expressed in a questionnaire survey were in good agreement with the preference for marbling among the 'moderate-fat and distinctive taste likers'. CONCLUSION: These results indicate that moderately marbled beef is a potent category in the Japanese beef market. © 2017 Society of Chemical Industry.

MicroRNA-33b downregulates the differentiation and development of porcine preadipocytes.

Sterol regulatory element binding transcription factor (SREBF) is a key transcription regulator for lipid homeostasis. MicroRNA-33b (miR-33b) is embedded in intron 16 of porcine SREBF1 and is conserved among most mammals. Here, we investigated the effect of miR-33b on adipocyte differentiation and development in porcine subcutaneous pre-adipocytes (PSPA). PSPA were transiently transfected with miR-33b, and adipose differentiation was then induced. Delayed adipose differentiation and decreased lipid accumulation were observed in miR-33b-transfected PSPA. Computational predictions suggested that miR-33b may target early B cell factor 1 (EBF1), an adipocyte activator of lipogenesis regulators such as CCAAT-enhancer binding protein alpha (C/EBPα) and peroxisome proliferator-activated receptor gamma (PPARγ). Both gene and protein expression of EBF1 were downregulated in miR-33b-transfected PSPA, followed by considerable decreases in the expression of C/EBPα and PPARγ and their downstream lipogenic genes. However, miR-33b transfection did not markedly affect mRNA and protein expression of SREBF1. We also investigated differences in the expression of miR-33b and lipogenic genes in subcutaneous fat tissues between 5-month-old crossbred gilts derived from Landrace (lean-type) and Meishan (fatty-type) boars. Landrace-derived crossbred gilts expressed more miR-33b and less lipogenic genes than did gilts derived from Meishan. Our results suggest that miR-33b affected the differentiation and development of PSPA by attenuating the lipogenic gene expression cascade through EBF1 to C/EBPα and PPARγ. The differential expression of miR-33b observed in crossbred gilts may in part account for differences in lipogenic gene expression and the fat:lean ratio between pig breeds.

Radiocesium distribution in the tissues of Japanese Black beef heifers fed fallout-contaminated roughage due to the Fukushima Daiichi Nuclear Power Station accident.

This study examined the accumulation and tissue distribution of radioactive cesium nuclides in Japanese Black beef heifers raised on roughage contaminated with radioactive fallout due to the accident at the Fukushima Daiichi Nuclear Power Station on March 2011. Radiocesium feeding increased both (134)Cs and (137)Cs levels in all tissues tested. The kidney had the highest level and subcutaneous adipose had the lowest of radioactive cesium in the tissues. Different radioactive cesium levels were not found among parts of the muscles. These results indicate that radiocesium accumulated highly in the kidney and homogenously in the skeletal muscles in the heifers.

Meat consumption and consumer attitudes in Japan: An overview.

Among Asian countries, Japan has the shortest history of eating meat in its food culture. It was only after 2007 that household fresh meat consumption surpassed fresh fish consumption in Japan. Although it was forecast that slowing population and economic growth would limit the demand for meat, household meat consumption in 2020 increased remarkably from that in 2019, perhaps due to COVID-19. Meat consumption has regional variations within Japan attributable to historical background. Japanese consumers prefer domestically produced meat and focus on the visual characteristics of meat, in particular marbling. Extrinsic factors such as information also contribute to Japanese consumers' meat choices more than the quality of the meat. Although Japanese consumers are concerned about the safety of meat, reassurance from appropriate inspection will restore their purchasing intention. Novel factors such as animal welfare and environment-friendly production are also recognized in Japan. Also notable is that wild animal meat consumption is beginning to increase in recent years.

Estimation of discrimination threshold for emulsified chicken oil in chicken broth.

Although fat content affects the texture and flavor of meat and meat products, the fat discrimination thresholds are unknown. This study aimed to elucidate the discrimination threshold of fat in meat products using broth from chicken thigh meat as a meat taste model. In Experiment 1, triangle tests were conducted between 1%, 0.2%, 0.04%, and 0.008% (w/v) chicken oil-supplemented broth and broth without chicken oil. The results indicated the discrimination threshold to be between 0.04% and 0.008% (w/v). In Experiment 2, similar triangle tests were conducted using oil supplementation at 0.1%, 0.0333%, 0.0111%, and 0.0037% to refine the discrimination threshold. Logistic regression analysis revealed that the discrimination threshold of emulsified chicken oil in chicken broth was 0.0387% (w/v). We demonstrated that chicken oil made a sensory difference in chicken broth at a low concentration and indicates that the chicken oil strongly affects the sensory characteristics of chicken broth.

11-Ketotestosterone is a major androgen produced in porcine adrenal glands and testes.

Porcine steroid hormone profiles have some unique characteristics. We previously studied human and murine steroidogenesis using steroidogenic cells-derived from mesenchymal stem cells (MSCs). To investigate porcine steroidogenesis, we induced steroidogenic cells from porcine subcutaneous preadipocytes (PSPA cells), which originate from MSCs. Using cAMP, adenovirus-mediated introduction of steroidogenic factor-1 (SF-1)/adrenal 4-binding protein (Ad4BP) induced the differentiation of PSPA cells into sex steroid-producing cells. Introducing SF-1/Ad4BP also induced the aldo-keto reductase 1C1 (AKR1C1) gene. Porcine AKR1C1 had 17ß-hydroxysteroid dehydrogenase activity, which converts androstenedione and 11-ketoandrostenedione into testosterone (T) and 11-ketotestosteorne (11KT). Furthermore, differentiated cells expressed hydroxysteroid 11ß-dehydrogenase 2 (HSD11B2) and produced 11KT. HSD11B2 was expressed in testicular Leydig cells and the adrenal cortex. 11KT was present in the plasma of both immature male and female pigs, with slightly higher levels in the male pigs. T levels were much higher in the male pigs. It is noteworthy that in the female pigs, the 11KT levels were >10-fold higher than the T levels. However, castration altered the 11KT and T plasma profiles in the male pigs to near those of the females. 11KT induced endothelial nitric oxide synthase (eNOS) in porcine vascular endothelial cells. These results indicate that 11KT is produced in porcine adrenal glands and testes, and may regulate cardiovascular functions through eNOS expression.

Changes in thiamin contents in porcine muscles and liver during growth.

Changes in the thiamin contents in three types of porcine muscle and porcine liver during growth were investigated. The muscular thiamin content was lower at the newborn stage than at fetal stage, and increased after the weaning period. The liver thiamin content, however, remained unchanged from the fetal stage to 5 months old. The changes in thiamin contents were different between Landrace and Meishan pigs.

A non-destructive method to monitor changes in a troponin T peptide in beef drip with a monoclonal antibody.

To simplify the monitoring of postmortem beef aging, we established a system to detect a troponin T (TnT) peptide fragment in bovine muscle drip (natural exudates) with an original monoclonal antibody. The antibody was raised against a synthetic peptide APPPPAEVPEVHEEVH corresponding to the N-terminal region of bovine fast-type TnT. In a competitive enzyme-linked immunosorbent assay (ELISA), our antibody detected the standard peptide dose-dependently. According to the monitoring examination with a competitive ELISA during 22days postmortem, the concentration of the peptide in both the drip and trichloroacetic acid extracts from the longissimus muscle (n=4) significantly increased in parallel, up to 10nmol/ml and 16.4nmol/g at day 14 postmortem, respectively. These events were accompanied by an increase in the conventional 30kDa fragment in western blot analysis and a decrease in the Warner-Bratzler shear force value of the beef from 5.0 to 2.4N/cm(2). The peptide detection system using drips with the antibody has advantages applicable to a non-destructive, simple, quick, and on-site monitoring method, such as immunochromatography.

Assessment of the dynamics of sensory perception of Wagyu beef strip loin prepared with different cooking methods and fattening periods using the temporal dominance of sensations.

In this study, we assessed the relative sensory perception of Wagyu beef using temporal dominance of sensations (TDS), which is a dynamic sensory method that captures the "dominance of sensation" throughout food consumption. In addition, we checked the integrity of the TDS by comparing the TDS results with a physicochemical analysis. Strip loins were obtained from 24- and 28-month-old Japanese Black cattle ("Wagyu") and were cooked by grilling (yakiniku) or boiling (shabu-shabu). Temporal dominance of sensations was then used to evaluate the four types of samples. "Tender and/or soft," "juicy," "dry," "fat melting," "fat taste," "umami," "sweet taste," and "butter odor" were dominant in at least one of the sample types, with the yakiniku cooking method highlighting texture- and fat-related sensory characteristics, and the shabu-shabu cooking method highlighting flavor-related sensory characteristics. In addition, beef obtained from the 24-month-old Wagyu was significantly more "dry" than that of the 28-month-old cattle, reflecting their different cooking loss. Temporal dominance of sensations successfully demonstrated the dominant sensory perceptions of Wagyu beef prepared with different cooking methods and fattening periods.

Descriptive Sensory Traits of Cooked Eggs Laid from Hens Fed Rice Grain.

Descriptive sensory characteristics of eggs produced by conventional corn-based feeding and unhulled whole rice grain-feeding were compared in two cooking procedures using a trained panel. Rice-feeding significantly decreased brothy and roasted odor in eggs cooked into half-cooked egg yolks, and decreased the creamy odor, smoothness and moisture of eggs cooked into custard puddings. However, a statistical interaction between rice-feeding and production farm was not observed in every sensory attribute. These findings indicated that replacing corn with unhulled whole rice grain in diets for laying hens alters the sensory attributes of eggs.

Differences in gene expression profiles for subcutaneous adipose, liver, and skeletal muscle tissues between Meishan and Landrace pigs with different backfat thicknesses.

Backfat thickness is one of the most important traits of commercially raised pigs. Meishan pigs are renowned for having thicker backfat than Landrace pigs. To examine the genetic factors responsible for the differences, we first produced female crossbred pig lines by mating Landrace (L) × Large White (W) × Duroc (D) females (LWD) with Landrace (L) or Meishan (M) boars (i.e., LWD × L = LWDL for Landrace offspring and LWD × M = LWDM for the Meishan offspring). We confirmed that LWDM pigs indeed had a thicker backfat than LWDL pigs. Next, we performed gene expression microarray analysis in both genetic lines to examine differentially expressed genes (DEGs) in energy metabolism-related tissues, subcutaneous adipose (fat), liver, and longissimus dorsi muscle tissues. We analyzed the annotation of DEGs (2-fold cutoff) to functionally categorize them by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways. The number of DEGs in muscle tissues of both lines was much less than that in fat and liver tissues, indicating that DEGs in muscle tissues may not contribute much to differences in backfat thickness. In contrast, several genes related to muscle (in fat tissue) and lipid metabolism (in liver tissue) were more upregulated in LWDM pigs than LWDL pigs, indicating that those DEGs might be responsible for differences in backfat thickness. The different genome-wide gene expression profiles in the fat, liver, and muscle tissues between genetic lines can provide useful information for pig breeders.

Double phosphorylation of the myosin regulatory light chain during rigor mortis of bovine Longissimus muscle.

UNLABELLED: To investigate changes in myosin light chains (MyLCs) during postmortem aging of the bovine longissimus muscle, we performed two-dimensional gel electrophoresis followed by identification with matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The results of fluorescent differential gel electrophoresis showed that two spots of the myosin regulatory light chain (MyLC2) at pI values of 4.6 and 4.7 shifted toward those at pI values of 4.5 and 4.6, respectively, by 24 h postmortem when rigor mortis was completed. Meanwhile, the MyLC1 and MyLC3 spots did not change during the 14 days postmortem. Phosphoprotein-specific staining of the gels demonstrated that the MyLC2 proteins at pI values of 4.5 and 4.6 were phosphorylated. Furthermore, possible N-terminal region peptides containing one and two phosphoserine residues were detected in each mass spectrum of the MyLC2 spots at pI values of 4.5 and 4.6, respectively. These results demonstrated that MyLC2 became doubly phosphorylated during rigor formation of the bovine longissimus, suggesting involvement of the MyLC2 phosphorylation in the progress of beef rigor mortis. KEYWORDS: Bovine; myosin regulatory light chain (RLC, MyLC2); phosphorylation; rigor mortis; skeletal muscle.

Postmortem changes in bovine troponin T isoforms on two-dimensional electrophoretic gel analyzed using mass spectrometry and western blotting: The limited fragmentation into basic polypeptides.

To comprehend postmortem changes in troponin T (TnT), whole beef proteins were developed on a two-dimensional electrophoretic gel. Multiple TnT-related spots were identified by both western blotting and MALDI-TOF MS utilizing bovine TnT isoform mRNA sequences. More than 10 TnT fast-type isoform spots (pI 5.7-9.6<) and the two slow-type isoform spots (pI 5.6-5.7) were observed at slaughter. All the isoforms were degraded exclusively into basic spots (pI 9.6<) at day 14 postmortem. Some TnT-related phosphorylated spots present at slaughter had disappeared by day 14, suggesting that the phosphorylated N-terminal region was cut off during beef aging. The intact isoforms and the fragments were identified by the MS with sequence coverage of 20.8-62.7%, and two of the fragments included the cutting site peptide of a conventional 30kDa or of a slow TnT-derived fragment. These results revealed that all of the TnT isoforms are cut exclusively in the glutamic acid-rich amino-terminal region during postmortem aging.

Difference in postmortem degradation pattern among troponin T isoforms expressed in bovine longissimus, diaphragm, and masseter muscles.

The postmortem degradation of troponin T (TnT) in bovine longissimus (LT), diaphragm (DP), and masseter (MS) was analyzed. A 28.3kDa (conventional 30kDa) fragment of fast-type TnT isoforms showed the highest content in both LT and DP, where a 35.4kDa isoform had the highest expression among the other fast isoforms. Meanwhile, a 26.0kDa fragment was found to be the most highly produced among the fast TnT fragments in MS, where the expression of 36.5 and 32.8kDa isoforms was higher than that of 35.4 and 34.8kDa isoforms. Thus, the compositions of both the intact TnT isoform proteins and the postmortem fragments differed among the muscles examined, indicating that each TnT isoform degrades into a specific fragment in each muscle. Among the muscles, the LT muscle showed a high extent of TnT degradation and the highest expression of fast TnT isoforms containing a taste-related peptide sequence.

Dynamics of protein secretion during adipocyte differentiation.

The major functions of adipocytes include both lipid storage and the production of secretory factors. However, the type of proteins released from mouse 3T3-L1 cells during adipocyte differentiation remains poorly understood. We examined the dynamics of secreted proteins during adipocyte differentiation using mass spectrometry (MS) combined with an iTRAQ (®) labeling method that enables the simultaneous analysis of relative protein expression levels. A total of 215 proteins were identified and quantified from approximately 10 000 MS/MS spectra. Of these, approximately 38% were categorized as secreted proteins based on gene ontology classification. Adipokine secretion levels were increased with the progression of differentiation. By contrast, levels of fibril collagen components, such as subunits of type I and III collagens, were decreased during differentiation. Basement membrane components attained their peak levels at day 4 when small lipid droplets accumulated in differentiated 3T3-L1 cells. Simultaneously, peak levels of collagen microfibril components that comprise type V and VI collagen subunits were also observed. Our data demonstrated that extracellular matrix components were predominantly released during the early and middle stages of adipocyte differentiation, with a subsequent increase in the secretion of adipokines. This suggests that 3T3-L1 cells secrete adipokines after their ECM is constructed during adipocyte differentiation.

Simultaneous imaging of fat crystallinity and crystal polymorphic types by Raman microspectroscopy.

The crystalline states of fats, i.e., the crystallinity and crystal polymorphic types, strongly influence their physical properties in fat-based foods. Imaging of fat crystalline states has thus been a subject of abiding interest, but conventional techniques cannot image crystallinity and polymorphic types all at once. This article demonstrates a new technique using Raman microspectroscopy for simultaneously imaging the crystallinity and polymorphic types of fats. The crystallinity and ß' crystal polymorph, which contribute to the hardness of fat-based food products, were quantitatively visualized in a model fat (porcine adipose tissue) by analyzing several key Raman bands. The emergence of the ß crystal polymorph, which generally results in food product deterioration, was successfully imaged by analyzing the whole fingerprint regions of Raman spectra using multivariate curve resolution alternating least squares analysis. The results demonstrate that the crystalline states of fats can be nondestructively visualized and analyzed at the molecular level, in situ, without laborious sample pretreatments.

Transferrin and inhibin mRNA in mature pig Sertoli cells.

Aims: There is increasing concern about the effect of environmental toxins and endocrine disrupters on human spermatogenesis but ethical considerations prohibit direct research. Therefore, we developed a method of isolating mature pig Sertoli cells and studying the levels of mRNA of transferrin and inhibin, markers of Sertoli cell function, using real-time polymerase chain reaction analysis. Methods: Sertoli cells from mature Meishan boars were isolated and cultured. The mRNA was isolated from the cells after 3 days of treatment with follicle-stimulating hormone (FSH), testosterone and ß-estradiol. The amounts of transferrin and inhibin mRNA were analyzed by real-time polymerase chain reaction and the relative level of mRNA was calculated. Results: FSH tended to increase the levels of transferrin and inhibin mRNA, as did the combinations of FSH and the steroids. The effect of testosterone and ß-estradiol alone on the level of mRNA was less than that of FSH. Beta-estradiol treatment resulted in a dose-dependent decrease in mRNA. Conclusion: The Sertoli cell culture used in the present study appears to have a normal secretory function because the mRNA levels of both markers increased after FSH treatment. The suppressive effect of ß-estradiol on inhibin mRNA level suggests that ß-estradiol has an effect on the function of Sertoli cells. (Reprod Med Biol 2005; 4: 259 -264).

Genomic structural analysis of porcine fatty acid desaturase cluster on chromosome 2.

Fatty acid composition is an economically important trait in meat-producing livestock. To gain insight into the molecular genetics of fatty acid desaturase (FADS) genes in pigs, we investigated the genomic structure of the porcine FADS gene family on chromosome 2. We also examined the tissue distribution of FADS gene expression. The genomic structure of FADS family in mammals consists of three isoforms FADS1, FADS2 and FADS3. However, porcine FADS cluster in the latest pig genome assembly (Sscrofa 10.2) containing some gaps is distinct from that in other mammals. We therefore sought to determine the genomic structure, including the FADS cluster in a 200-kbp range by sequencing gap regions. The structure we obtained was similar to that in other mammals. We then investigated the porcine FADS1 transcription start site and identified a novel isoform named FADS1b. Phylogenetic analysis revealed that the three members of the FADS cluster were orthologous among mammals, whereas the various FADS1 isoforms identified in pigs, mice and cattle might be attributable to species-specific transcriptional regulation with alternative promoters. Porcine FADS1b and FADS3 isoforms were predominantly expressed in the inner layer of the subcutaneous adipose tissue. Additional analyses will reveal the effects of these functionally unknown isoforms on fatty acid composition in pig fat tissues.