Browsing by Subject "Meat"

Now showing 1 - 5 of 5

Effects of fingerroot (Boesenbergia pandurata) oil on microflora as an antimicrobial agent and on the formation of heterocyclic amines in fried meatballs
(2024) Soikam, Panida; Rachtanapun, Chitsiri; Suriyarak, Sarisa; Weiss, Jochen; Gibis, Monika
This study aimed to determine the antibacterial activity of the essential oil of fingerroot (Boesenbergia pandurata) (EOF) as a natural preservative in ground meat and its effect on the formation of heterocyclic amines (HAs) in pan-fried meatballs. EOF was applied either by adding it to ground pork or marinating pork in it before grinding. In addition, the antibacterial activity of EOF was tested. Aerobic mesophilic total viable count (TVC), lactic acid bacteria (LAB), and Enterobacteriaceae bacteria were monitored. The results show that EOF exhibited strong antibacterial activity when added at concentrations of 1.0 and 2.5 wt%. Antimicrobial activity against TVC, LAB, and especially Enterobacteriaceae bacteria was observed at all EOF concentrations (0.25, 0.5, 1.0, and 2.5 wt%). A 2.5% concentration of EOF applied by marinating trimmings can extend the shelf-life of ground pork to 18 days, while 2.5% EOF applied via addition can extend the shelf-life to 15 days, compared with 3 days for the control sample. After frying the meatballs, the inhibitory effect on the formation of heterocyclic amines was only significant for MeIQx with the highest addition of EOF (2.5 wt%). Significant increases in the concentrations of all other HAs were determined by adding EOF (2.5 wt%).
Influence of muscle type and microstructure on iridescence in cooked, cured pork meat products
(2021) Ruedt, Chiara; Gibis, Monika; Weiss, Jochen
Microstructural factors associated with surface iridescence in cooked, cured pork products were investigated. Meat iridescence is a commonly observed physical phenomenon in raw meat and meat products that consist of intact mus- cle tissue. Since the purchase decision of consumers is mainly driven by the first impression of meat color and appearance, products showing colorful iri- descence may be rejected. Four different muscles (RF: M. rectus femoris, BF: M. biceps femoris, ST: M. semitendinosus, and LD: M. longissimus thoracis et lum- borum) were brine-injected, cooked, sliced, and iridescence was evaluated by digital image analysis and sensory analysis. Sarcomere lengths, fiber diameters, and surface microstructure were analyzed in iridescent and noniridescent sec- tions. Highest iridescence extent by image analysis was found in LD (37.3 ± 16.4%), and highest overall iridescence score (extent and intensity, 6.11 ± 1.78) was observed in BF. Sarcomere lengths did not differ significantly between iridescent (1.05 ± 0.09 µm LD) and noniridescent areas (1.08 ± 0.94 µm LD) within mus- cles (p > 0.05). Iridescent sections showed smooth and ordered surface structures with cross-sectioned myofibers, whereas in noniridescent sections, surfaces were more unstructured and myofibers obliquely cut. The results of the study indicate that the sarcomere length and fiber diameters may thus be only of minor impor- tance for the explanation of meat iridescence in cooked meat products and are rather related to multiple scattering and absorption effects on smaller structural entities such as the myofilament lattice or larger entities such as fiber bundles. Practical application: Iridescence can be a problem for the meat industry due to consumers concerns about green-iridescent colors in meat. The underlying mechanisms and structures have not yet been fully clarified, and thus no prac- tical solutions to eliminate iridescence have been found so far. This research presents new insights into the structural attributes that are interrelated with meat iridescence and shows that iridescence is rather influenced by cutting angle of muscle fibers and surface homogeneity than by muscle fiber diameters or sar- comere lengths. This should be considered by the industry when seeking for ways to reduce the potential problem of iridescence
Meat color and iridescence: Origin, analysis, and approaches to modulation
(2023) Ruedt, Chiara; Gibis, Monika; Weiss, Jochen
Meat color is an important aspect for the meat industry since it strongly determines the consumers’ perception of product quality and thereby significantly influences the purchase decision. Emergence of new vegan meat analogs has renewed interest in the fundamental aspects of meat color in order to replicate it. The appearance of meat is based on a complex interplay between the pigment‐based meat color from myoglobin and its chemical forms and light scattering from the muscle's microstructure. While myoglobin biochemistry and pigment‐based meat color have been extensively studied, research on the physicochemical contribution of light scattering to meat color and the special case of structural colors causing meat iridescence has received only little attention. Former review articles focused mostly on the biochemical or physical mechanisms rather than the interplay between them, in particular the role that structural colors play. While from an economic point of view, meat iridescence might be considered negligible, an enhanced understanding of the underlying mechanisms and the interactions of light with meat microstructures can improve our overall understanding of meat color. Therefore, this review discusses both biochemical and physicochemical aspects of meat color including the origin of structural colors, highlights new color measurement methodologies suitable to investigate color phenomena such as meat iridescence, and finally presents approaches to modulate meat color in terms of base composition, additives, and processing.
Phenotypic and genetic analysis of meat production traits in German Merinoland purebred and crossbred lambs
(2016) Schiller, Katja; Bennewitz, Jörn
The overall aims of the present thesis were to investigate various meat quality (MQ) traits including branched chain fatty acids and their correlation to sensory traits and to perform DNA-based and quantitative genetic analysis for growth, carcass and MQ traits using the data set with about 1600 phenotyped lambs. The lambs were Merinoland (ML) lambs and lambs of five crossbreds of meat type sire breeds and Merinoland ewes. The crosses were CH (Charollais × ML), IF (Ile de France × ML), SK (German black-headed mutton sheep (BHM) × ML), SU (Suffolk × ML) and TX (Texel × ML). In chapter one, growth curves, daily gain and feed conversion of ML sheep and the five ML crosses were investigated via mixed linear models. Linear and Gompertz models were fitted and the quality of fit was assessed. Differences in the model parameters were detected between crosses, genders and birth types. According to the parameters, coefficient of determination and mean square error, the Gompertz provided a better fit compared to the linear model. Additionally feed conversion rate and daily gain were observed, with only the crosses IF and TX showing significant superiority in these traits compared to purebred ML. For practical reasons, however, the common trait daily gain can be recommended to use for breeding purpose, despite if altering the shape of a growth curve is attractive because of e.g. possible lower maintenance costs for a flock. In chapter two, lamb meat and fat of the crosses and ML was investigated for concentration of three branched chain fatty acids (4-Me8:0, 4-ET8:0 and 4-Me9:0) and its correlation to sensory abnormality. Differences between crosses and between sexes were determined, but no significant correlations to sensory traits were found. In chapters three to five, genetic background and genetic parameters were investigated and a chromosome-wide association study imputing SNP panels was undertaken. Furthermore, the possibilities of implementation of this data to improve breeding programs were discussed. Chapter three focuses on genetic parameters of growth, carcass and MQ traits in purebred ML and crossbred lambs. A series of analyses for twelve traits were performed and heritabilities and genetic correlations were estimated using general linear mixed models. Several significant correlations and low to moderate heritabilities were found, indicating that selection on these traits is possible. In chapter four, a targeted association mapping was undertaken with about 330 SNPs using two different statistical models, one with estimation of SNP effects across all crosses and the other with SNP effects per cross. The investigated traits were growth, carcass and MQ traits. In this connection, several weak significant SNPs were revealed. In chapter five, F1 lambs were genotyped on selected chromosomes with a very low SNP panel and imputed via Illumina Ovine 50k SNP BeadChip genotypes from the sires and purebred ML. These were included in a haplotype bibliography before. Furthermore, chromosome-wise association analyses using single marker mixed linear models were performed for MQ, carcass, and growth traits. This was done using the imputed genotypes and the trait phenotypes. Several significant associations were detected, e.g. for the traits shoulder width and cutlet area, and these were discussed with regard to other literature reports as well as their use for practical breeding purpose. The thesis ends with a general discussion.
Variations in the metabolome of unaged and aged beef from black-and-white cows and heifers by 1H NMR spectroscopy
(2023) Bischof, Greta; Januschewski, Edwin; Witte, Franziska; Terjung, Nino; Heinz, Volker; Juadjur, Andreas; Gibis, Monika
(1) Background: The selection of raw material and the postmortem processing of beef influence its quality, such as taste. In this study, the metabolome of beef from cows and heifers is examined for differences during aging. (2) Methods: Thirty strip loins from eight heifers and seven cows (breed code: 01–SBT) were cut into ten pieces and aged for 0, 7, 14, 21 and 28 days. Samples from the left strip loins were wet-aged in vacuum, while samples from right strip loins were dry-aged at 2 °C and 75% relative humidity. The beef samples were extracted with methanol–chloroform–water, and the polar fraction was used for 1H NMR analysis. (3) Results: The PCA and OPLS-DA showed that the metabolome of cows and heifers varied. Eight metabolites revealed significant differences (p < 0.05) in the samples from cows and heifers. The aging time and aging type of beef also affected the metabolome. Twenty-eight and 12 metabolites differed significantly (p < 0.05) with aging time and aging type, respectively. (4) Conclusions: The variations between cows and heifers and aging time affect the metabolome of beef. By comparison, the influence of aging type is present but less pronounced.