• Partitioning of starter bacteria and added exogenous enzyme activities between curd and whey during Cheddar cheese manufacture

      Doolan, I. A.; Nongonierma, Alice B.; Kilcawley, Kieran; Wilkinson, M.G.; Department of Agriculture, Food and the Marine, Ireland; 04/R&D/C/238 (Elsevier, 26/07/2013)
      Partitioning of starter bacteria and enzyme activities was investigated at different stages of Cheddar cheese manufacture using three exogenous commercial enzyme preparations added to milk or at salting. The enzyme preparations used were: Accelase AM317, Accelase AHC50, Accelerzyme CPG. Flow cytometric analysis indicated that AHC50 or AM317 consisted of permeabilised or dead cells and contained a range of enzyme activities. The CPG preparation contained only carboxypeptidase activity. Approximately 90% of starter bacteria cells partitioned with the curd at whey drainage. However, key enzyme activities partitioned with the bulk whey in the range of 22%–90%. An increased level of enzyme partitioning with the curd was observed for AHC50 which was added at salting, indicating that the mode of addition influenced partitioning. These findings suggest that further scope exists to optimise both bacterial and exogenous enzyme incorporation into cheese curd to accelerate ripening.
    • Performances of full cross-validation partial least squares regression models developed using Raman spectral data for the prediction of bull beef sensory attributes

      Zhao, Ming; Nian, Yingqun; Allen, Paul; Downey, Gerard; Kerry, Joseph P.; O’Donnell, Colm P.; Teagasc Walsh Fellowship Programme (Elsevier BV, 2018-04-23)
      The data presented in this article are related to the research article entitled “Application of Raman spectroscopy and chemometric techniques to assess sensory characteristics of young dairy bull beef” [1]. Partial least squares regression (PLSR) models were developed on Raman spectral data pre-treated using Savitzky Golay (S.G.) derivation (with 2nd or 5th order polynomial baseline correction) and results of sensory analysis on bull beef samples (n = 72). Models developed using selected Raman shift ranges (i.e. 250–3380 cm−1, 900–1800 cm−1 and 1300–2800 cm−1) were explored. The best model performance for each sensory attributes prediction was obtained using models developed on Raman spectral data of 1300–2800 cm−1.
    • Physical, textural and sensory characteristics of reduced sucrose cakes, incorporated with clean-label sugar-replacing alternative ingredients

      Milner, Laura; Kerry, Joseph P.; O'Sullivan, Maurice G.; Gallagher, Eimear; Department of Agriculture, Food and the Marine (Elsevier BV, 2020-01)
      High levels of sucrose in foods present a great risk of obesity and type 2 diabetes. Therefore a low sucrose intake is strongly recommended. Sweet baked products incorporate high levels of sucrose. Sucrose in the original cake formulation was reduced and replaced with apple pomace, whey permeate, oligofructose, polydextrose. An acceptable sucrose reduction of between 21 and 27% was achieved. Cakes containing apple pomace had the lowest specific volume (1.8 cm3/g) and highest crumb firmness (8.60 N) (P < .05). Apple pomace and whey permeate had a significantly decreased L* values of the crust (P < .05). Moisture content of the cake crumb was increased significantly with the addition of oligofructose, whey permeate and polydextrose. All treatments resulted in a significant increase of the water activity of the cake crumb compared to the control (P < .05). Crumb cell structure was maintained as shown by 2-D and confocal imaging. Sensory trials revealed the reformulated cakes were acceptable to panellists.
    • Physicochemical Characteristics of Protein-Enriched Restructured Beef Steaks with Phosphates, Transglutaminase, and Elasticised Package Forming

      Baugreet, Sephora; Kerry, Joseph P.; Allen, Paul; Gallagher, Eimear; Hamill, Ruth; Irish Department of Agriculture, Food and the Marine; Teagasc Walsh Fellowship Programme; 11/F/045 (Hindawi Limited, 2018)
      Restructured beef steaks were formulated by adding protein-rich ingredients (pea protein isolate (PPI), rice protein (RP), and lentil flour (LF) (at 4 and 8%)), phosphate (0.2%), and two binding agents: 1% (TG) and 0.15% (TS). The effects of their addition on the physicochemical properties of the beef steaks were investigated. Protein content of the RP8TG sample was significantly higher than that of the control in both the raw and cooked state. Raw LF4TS exhibited greater () a values than the control; however, after the cooking process, L, a, and b values were similar for all treatments. Textural assessment showed that elevating protein level increased () hardness, chewiness, cohesiveness, and gumminess in cooked restructured steaks. LF addition reduced all textural values assessed, indicating a strong plant protein effect on texture modification. The commercial binder produced a better bind in combination with protein ingredients. This facilitated the production of uniformed restructured beef steaks from low-value beef muscles with acceptable quality parameters using a novel process technology.
    • Potential applications for virtual and augmented reality technologies in sensory science

      Crofton, Emily C.; Botinestean, Cristina; Fenelon, Mark; Gallagher, Eimear (Elsevier, 2019-06-19)
      Sensory science has advanced significantly in the past decade and is quickly evolving to become a key tool for predicting food product success in the marketplace. Increasingly, sensory data techniques are moving towards more dynamic aspects of sensory perception, taking account of the various stages of user-product interactions. Recent technological advancements in virtual reality and augmented reality have unlocked the potential for new immersive and interactive systems which could be applied as powerful tools for capturing and deciphering the complexities of human sensory perception. This paper reviews recent advancements in virtual and augmented reality technologies and identifies and explores their potential application within the field of sensory science. The paper also considers the possible benefits for the food industry as well as key challenges posed for widespread adoption. The findings indicate that these technologies have the potential to alter the research landscape in sensory science by facilitating promising innovations in five principal areas: consumption context, biometrics, food structure and texture, sensory marketing and augmenting sensory perception. Although the advent of augmented and virtual reality in sensory science offers new exciting developments, the exploitation of these technologies is in its infancy and future research will understand how they can be fully integrated with food and human responses. Industrial relevance: The need for sensory evaluation within the food industry is becoming increasingly complex as companies continuously compete for consumer product acceptance in today's highly innovative and global food environment. Recent technological developments in virtual and augmented reality offer the food industry new opportunities for generating more reliable insights into consumer sensory perceptions of food and beverages, contributing to the design and development of new products with optimised consumer benefits. These technologies also hold significant potential for improving the predictive validity of newly launched products within the marketplace.
    • Predicting the eating quality of meat

      Mullen, Anne Maria; Murray, Brendan; Troy, Declan J.; European Union (Teagasc, 2000-12)
      A novel, water soluble protein fragment [1735Da] was isolated from beef striploin and characterised. As soluble components of the proteolytic system are easily extracted from muscle they may be suitable for routine factory analysis. This fragment originated from the important myofibrillar protein, troponin T and may serve as a tenderness indicator.
    • Preliminary investigation of the antimicrobial and mechanisms of resistance of Enterobacteria isolated from minced meat in the Northeast of Algeria: The case of butchers from Constantine

      Leila Dib, Amira; Chahed, Amina; Lakhdara, Nedjoua; Agabou, Amir; Boussena, Sabrina; Ghougal, Khireddine; Lamri, Melisa; Sana Kerrour, Nessrine; Kadja, Louiza; Bouaziz, Assia; et al. (Open Access Text Pvt, Ltd., 2019)
      Food products of animal origin such as fresh meat are easily contaminated by microorganisms if handling, processing and storage conditions are not fully respected. The present study aimed first to evaluate the bacterial load and microbial contamination rates of ground raw beef to identify the main pathogenic flora that dominate and second, to determine the resistance patterns and extended-spectrum beta-lactamase (ESBL) of isolated Gram-negative strains against certain families of antibiotics. Therefore, 39 samples have been collected from 5 butcher shops located in Constantine province in the North-East of Algeria. The samples were analysed for total bacterial count, presence of total and faecal coliforms, Staphylococci and Salmonella. Furthermore, 23 antibiotics were tested using the diffusion method on Mueller-Hinton agar, towards 22 strains isolates. Bacterial analyses showed a high contamination by total aerobic bacteria, total and faecal coliforms. Escherichia coli, Citrobacter spp., Enterobacter spp., Hafnia alvei, Salmonella pullorum and Staphylococcus spp (except Staphylococcus aureus) were further revealed in some samples. The results of the antibiogram test exhibit multi-resistance to more than eight antibiotics with varied effects. From the whole tested strains isolates, the fully susceptibility effect was for spectinomycin (SPT). This study reveals that the analysed minced meat was found to be highly contaminated with antibiotic resistant bacteria. This study allows concluding that appropriate use of antibiotics in compliance with good hygiene practices is essential to reduce the antibiotic resistance identified in this preliminary study.
    • Preliminary study on the use of near infrared hyperspectral imaging for quantitation and localisation of total glucosinolates in freeze-dried broccoli

      Hernandez-Hierro, Jose Miguel; Esquerre, Carlos; Valverde, Juan; Villacreces, Salvador; Reilly, Kim; Gaffney, Michael; Gonzalez-Miret, Maria Lourdes; Heredia, Francisco J.; O'Donnell, Colm P.; Downey, Gerard; et al. (Elsevier, 15/11/2013)
      The use of hyperspectral imaging to (a) quantify and (b) localise total glucosinolates in florets of a single broccoli species has been examined. Two different spectral regions (vis–NIR and NIR), a number of spectral pre-treatments and different mask development strategies were studied to develop the quantitative models. These models were then applied to freeze-dried slices of broccoli to identify regions within individual florets which were rich in glucosinolates. The procedure demonstrates potential for the quantitative screening and localisation of total glucosinolates in broccoli using the 950–1650 nm wavelength range. These compounds were mainly located in the external part of florets.
    • Protein Array-Based Approach to Evaluate Biomarkers of Beef Tenderness and Marbling in Cows: Understanding of the Underlying Mechanisms and Prediction

      Gagaoua, Mohammed; Bonnet, Muriel; Picard, Brigitte; Pays de Loire Regional Council (MDPI AG, 2020-08-26)
      This study evaluated the potential of a panel of 20 protein biomarkers, quantified by Reverse Phase Protein Array (RPPA), to explain and predict two important meat quality traits, these being beef tenderness assessed by Warner–Bratzler shear force (WBSF) and the intramuscular fat (IMF) content (also termed marbling), in a large database of 188 Protected Designation of Origin (PDO) Maine-Anjou cows. Thus, the main objective was to move forward in the progression of biomarker-discovery for beef qualities by evaluating, at the same time for the two quality traits, a list of candidate proteins so far identified by proteomics and belonging to five interconnected biological pathways: (i) energy metabolic enzymes, (ii) heat shock proteins (HSPs), (iii) oxidative stress, (iv) structural proteins and (v) cell death and protein binding. Therefore, three statistical approaches were applied, these being Pearson correlations, unsupervised learning for the clustering of WBSF and IMF into quality classes, and Partial Least Squares regressions (PLS-R) to relate the phenotypes with the 20 biomarkers. Irrespective of the statistical method and quality trait, seven biomarkers were related with both WBSF and IMF, including three small HSPs (CRYAB, HSP20 and HSP27), two metabolic enzymes from the oxidative pathway (MDH1: Malate dehydrogenase and ALDH1A1: Retinal dehydrogenase 1), the structural protein MYH1 (Myosin heavy chain-IIx) and the multifunctional protein FHL1 (four and a half LIM domains 1). Further, three more proteins were retained for tenderness whatever the statistical method, among which two were structural proteins (MYL1: Myosin light chain 1/3 and TNNT1: Troponin T, slow skeletal muscle) and one was glycolytic enzyme (ENO3: β-enolase 3). For IMF, two proteins were, in this trial, specific for marbling whatever the statistical method: TRIM72 (Tripartite motif protein 72, negative) and PRDX6 (Peroxiredoxin 6, positive). From the 20 proteins, this trial allowed us to qualify 10 and 9 proteins respectively as strongly related with beef tenderness and marbling in PDO Maine-Anjou cows.
    • Proteomic biomarkers of beef colour

      Gagaoua, Mohammed; Hughes, Joanne; Terlouw, E.M. Claudia; Warner, Robyn D.; Purslow, Peter P.; Lorenzo, José M.; Picard, Brigitte; European Union; Enterprise Ireland; 713654; et al. (Elsevier BV, 2020-07)
      Background Implementation of proteomics over the last decade has been an important step toward a better understanding of the complex biological systems underlying the conversion of muscle to meat. These sophisticated analytical tools have helped to reveal the biochemical pathways involved in fresh meat colour and have identified key protein biomarkers. Scope and approach Until recently, there have been no detailed or critical studies on the role of protein biomarkers in determining meat colour. This review presents an integromics of recent muscle proteomic studies to investigate pathways and mechanisms of beef colour. A database was created from 13 independent proteomic-based studies including data on five muscles and a list of 79 proteins which were significantly correlated with colour traits. The database was subjected to a multistep analysis including Gene Ontology annotations, pathway analysis and literature mining. This report discusses the key protein biomarkers and the biological pathways associated with fresh beef colour. Biomarkers were prioritised by the frequency of identification and the need for future validation experiments is discussed. Key findings and conclusions This review identifies six pathways involved in beef colour including energy metabolism, heat shock and oxidative stress, myofibril structure, signalling, proteolysis and apoptosis. The data-mining of the list of the putative biomarkers showed that certain proteins, such as β-enolase (ENO3), Peroxiredoxin 6 (PRDX6), HSP27 (HSPB1), Phosphoglucomutase 1 (PGM1), Superoxide Dismutase [Cu-Zn] (SOD1) and μ-calpain (CAPN1) were consistently reported by multiple studies as being differentially expressed and having a significant role in beef colour. This integromics work proposes a list of 27 putative biomarkers of beef colour for validation using adapted high-throughput methods.
    • Proteomic biomarkers of beef colour

      Gagaoua, Mohammed; Hughes, Joanne; Terlouw, E.M. Claudia; Warner, Robyn D.; Purslow, Peter P.; Lorenzo, José M.; Picard, Brigitte; Marie Skłodowska-Curie grant agreement; Meat Technology Ireland; 713654; et al. (Elsevier, 2020-05-28)
      Background Implementation of proteomics over the last decade has been an important step toward a better understanding of the complex biological systems underlying the conversion of muscle to meat. These sophisticated analytical tools have helped to reveal the biochemical pathways involved in fresh meat colour and have identified key protein biomarkers. Scope and approach Until recently, there have been no detailed or critical studies on the role of protein biomarkers in determining meat colour. This review presents an integromics of recent muscle proteomic studies to investigate pathways and mechanisms of beef colour. A database was created from 13 independent proteomic-based studies including data on five muscles and a list of 79 proteins which were significantly correlated with colour traits. The database was subjected to a multistep analysis including Gene Ontology annotations, pathway analysis and literature mining. This report discusses the key protein biomarkers and the biological pathways associated with fresh beef colour. Biomarkers were prioritised by the frequency of identification and the need for future validation experiments is discussed. Key findings and conclusions This review identifies six pathways involved in beef colour including energy metabolism, heat shock and oxidative stress, myofibril structure, signalling, proteolysis and apoptosis. The data-mining of the list of the putative biomarkers showed that certain proteins, such as β-enolase (ENO3), Peroxiredoxin 6 (PRDX6), HSP27 (HSPB1), Phosphoglucomutase 1 (PGM1), Superoxide Dismutase [Cu-Zn] (SOD1) and μ-calpain (CAPN1) were consistently reported by multiple studies as being differentially expressed and having a significant role in beef colour. This integromics work proposes a list of 27 putative biomarkers of beef colour for validation using adapted high-throughput methods.
    • Reducing the incidence of boar taint in Irish pigs

      Allen, Paul; Joseph, Robin; Lynch, Brendan (Teagasc, 2001-04)
      Boar taint is an unpleasant odour that is released during cooking from some pork and products made from the meat and fat of non-castrated male pigs. Only a proportion of boars produce this odour and not all consumers are sensitive to it. Nevertheless it is a potential problem for the industry since an unpleasant experience can mean that a sensitive consumer may not purchase pork or pork products again. Some European countries are very concerned about this problem and most castrate all the male pigs not required for breeding. Irish pig producers ceased castration more than 20 years ago because boars are more efficient converters of feed into lean meat and a research study had shown that boar taint was not a problem at the carcass weights used in this country at that time.
    • Regulatory polymorphisms in the bovine Ankyrin 1 gene promoter are associated with tenderness and intra-muscular fat content

      Aslan, Ozlem; Sweeney, Torres; Mullen, Anne Maria; Hamill, Ruth M; Department of Agriculture, Food and the Marine, Ireland (Biomed Central, 15/12/2010)
      Recent QTL and gene expression studies have highlighted ankyrins as positional and functional candidate genes for meat quality. Our objective was to characterise the promoter region of the bovine ankyrin 1 gene and to test polymorphisms for association with sensory and technological meat quality measures. Results Seven novel promoter SNPs were identified in a 1.11 kb region of the ankyrin 1 promoter in Angus, Charolais and Limousin bulls (n = 15 per breed) as well as 141 crossbred beef animals for which meat quality data was available. Eighteen haplotypes were inferred with significant breed variation in haplotype frequencies. The five most frequent SNPs and the four most frequent haplotypes were subsequently tested for association with sensory and technological measures of meat quality in the crossbred population. SNP1, SNP3 and SNP4 (which were subsequently designated regulatory SNPs) and SNP5 were associated with traits that contribute to sensorial and technological measurements of tenderness and texture; Haplotype 1 and haplotype 4 were oppositely correlated with traits contributing to tenderness (P < 0.05). While no single SNP was associated with intramuscular fat (IMF), a clear association with increased IMF and juiciness was observed for haplotype 2. Conclusion The conclusion from this study is that alleles defining haplotypes 2 and 4 could usefully contribute to marker SNP panels used to select individuals with improved IMF/juiciness or tenderness in a genome-assisted selection framework.
    • RNA-seq of muscle from pigs divergent in feed efficiency and product quality identifies differences in immune response, growth, and macronutrient and connective tissue metabolism

      Horodyska, Justyna; Wimmers, Klaus; Reyer, Henry; Trakooljul, Nares; Mullen, Anne Maria; Lawlor, Peadar G; Hamill, Ruth M; European Union; 311794 (Biomed Central, 2018-11-01)
      Background Feed efficiency (FE) is an indicator of efficiency in converting energy and nutrients from feed into a tissue that is of major environmental and economic significance. The molecular mechanisms contributing to differences in FE are not fully elucidated, therefore the objective of this study was to profile the porcine Longissimus thoracis et lumborum (LTL) muscle transcriptome, examine the product quality from pigs divergent in FE and investigate the functional networks underpinning the potential relationship between product quality and FE. Results RNA-Seq (n = 16) and product quality (n = 40) analysis were carried out in the LTL of pigs differing in FE status. A total of 272 annotated genes were differentially expressed with a P < 0.01. Functional annotation revealed a number of biological events related to immune response, growth, carbohydrate & lipid metabolism and connective tissue indicating that these might be the key mechanisms governing differences in FE. Five most significant bio-functions altered in FE groups were ‘haematological system development & function’, ‘lymphoid tissue structure & development’, ‘tissue morphology’, ‘cellular movement’ and ‘immune cell trafficking’. Top significant canonical pathways represented among the differentially expressed genes included ‘IL-8 signalling’, ‘leukocyte extravasation signalling, ‘sphingosine-1-phosphate signalling’, ‘PKCθ signalling in T lymphocytes’ and ‘fMLP signalling in neutrophils’. A minor impairment in the quality of meat, in relation to texture and water-holding capacity, produced by high-FE pigs was observed. High-FE pigs also had reduced intramuscular fat content and improved nutritional profile in terms of fatty acid composition. Conclusions Ontology analysis revealed enhanced activity of adaptive immunity and phagocytes in high-FE pigs suggesting more efficient conserving of resources, which can be utilised for other important biological processes. Shifts in carbohydrate conversion into glucose in FE-divergent muscle may underpin the divergent evolution of pH profile in meat from the FE-groups. Moreover, altered amino acid metabolism and increased mobilisation & flux of calcium may influence growth in FE-divergent muscle. Furthermore, decreased degradation of fibroblasts in FE-divergent muscle could impact on collagen turnover and alter tenderness of meat, whilst enhanced lipid degradation in high-FE pigs may potentially underlie a more efficient fat metabolism in these animals.
    • Salt content and minimum acceptable levels in whole-muscle cured meat products

      Delgado-Pando, Gonzalo; Fischer, Estelle; Allen, Paul; Kerry, Joesph; O'Sullivan, Maurice; Hamill, Ruth; Department of Agriculture, Food and the Marine; 11F 026 (Elsevier, 2018-02-01)
      Reported salt levels in whole-muscle cured meat products differ substantially within and among European countries, providing substantial scope for salt reduction across this sector. The objective of this study was to identify the minimum acceptable salt levels in typical whole-muscle cured products in terms of physicochemical, microbial and sensorial properties. Salt levels in a small selection of commercial Irish meat products were determined to establish a baseline for reduction. Subsequently, eight different back bacon rasher and cooked ham products were produced with varying levels of salt: 2.9%, 2.5%, 2% and 1.5% for bacon, and 2%, 1.6%, 1.0% and 0.8% for ham. Salt reduction produced products with significantly harder texture and higher microbial counts, with no difference in the colour and affecting the sensory properties. Nonetheless, salt reduction proved to be feasible to levels of 34% and 19% in bacon and ham products, respectively, compared to baseline.
    • Seaweeds as promising resource of bioactive compounds: Overview of novel extraction strategies and design of tailored meat products

      Gullón, Beatriz; GAGAOUA, Mohammed; Barba, Francisco J.; Gullón, Patricia; Zhang, Wangang; Lorenzo, José M.; Axencia Galega de Innovación; CYTED; Spanish Ministry of Economy and Competitiveness; Generalitat Valenciana; et al. (Elsevier BV, 2020-06)
      Background Meat and meat products have been recently perceived by consumers as unhealthy foods. To avoid this drawback, the reformulation is a feasible approach that allows obtaining custom meat-based products that incorporate compounds with certain beneficial properties for health and remove other attributes considered negative. In this framework, the edible seaweeds have been proposed to offer interesting possibilities in the meat sector to develop functional foods as they are an excellent natural source of nutrients and biocompounds with myriad functionalities. Scope and approach This review collects aspects related to the recent technologies employed to obtain and isolate biocompounds from seaweeds. The use of whole seaweeds and their bioactive extracts to develop meat foods that confer them health properties while simultaneously reducing components considered unhealthy in meat are reviewed. Furthermore, the prevention of oxidation events was also described. Key findings and conclusions Several studies have demonstrated that the incorporation of whole seaweeds and their bioactives to reformulate meat products is an excellent approach to improve certain nutritional aspects considered “bad”. However, there are still some challenges regarding the organoleptic and sensory properties of the resulting products that affect the consumer acceptability. In conclusion, more research is necessary to overcome these gaps allowing put in the market seaweeds -based meat products.
    • Self-association of bovine β-casein as influenced by calcium chloride, buffer type and temperature

      Li, Meng; Auty, Mark; Crowley, Shane V.; Kelly, Alan L.; O'Mahoney, James A.; Brodkorb, Andre; Irish Dairy Levy Research Trust; Teagasc Walsh Fellowship Programme; MDDT 6261 (Elsevier, 2018-09-25)
      The aim of this study was to investigate the aggregation behaviour of a pure β-casein (β-CNpure) and a β-casein concentrate (β-CNconc) as a function of temperature, buffer type (pH 6.8) and the presence of CaCl2. The particle size distribution and turbidity of β-casein (β-CN) dispersions were measured by dynamic light-scattering (DLS) and UV/vis spectroscopy between 4 and 55 °C. Upon heating (4–55 °C), the particle size of both β-CN samples increased, indicating self-association via hydrophobic interactions. It was shown that the self-association of β-CN increased with increasing β-CN concentration and that β-CNpure self-associated at significantly lower concentration than β-CNconc. Both turbidity and particle size measurements showed that the β-CN samples had similar aggregation behaviour in water and imidazole buffer (pH 6.8) but differed in sodium phosphate buffer (pH 6.8), especially at higher ionic calcium concentrations. Fourier Transform Infrared (FTIR) spectroscopy revealed very little change in the secondary structure of β-CN during heating (4–55 °C). The microstructure of β-CN aggregates was monitored during heating from 10 to 55 °C, followed by cooling to 10 °C, using polarised light microscopy. Spherical and heterogeneous aggregates were observed when heated at temperatures above 37 °C, which were reversible upon cooling. This study confirmed that β-CN undergoes self-association on heating that reverses upon cooling, with the aggregation process being highly dependent on the purity of β-CN, the solvent type and the presence of ionic calcium.
    • Semi-supervised linear discriminant analysis

      Toher, Deirdre; Downey, Gerard; Murphy, Thomas Brendan; Science Foundation Ireland; Teagasc (Wiley, 02/07/2012)
      Fisher's linear discriminant analysis is one of the most commonly used and studied classification methods in chemometrics. The method finds a projection of multivariate data into a lower dimensional space so that the groups in the data are well separated. The resulting projected values are subsequently used to classify unlabeled observations into the groups. A semi-supervised version of Fisher's linear discriminant analysis is developed, so that the unlabeled observations are also used in the model fitting procedure. This approach is advantageous when few labeled and many unlabeled observations are available. The semi-supervised linear discriminant analysis method is demonstrated on a number of data sets where it is shown to yield better separation of the groups and improved classification over Fisher's linear discriminant analysis.
    • Sensory optimisation of salt-reduced corned beef for different consumer segments

      Conroy, Paula M.; O'Sullivan, Maurice; Hamill, Ruth; Kerry, Joseph; Department of Agriculture, Food and the Marine; 11/F/045 (Elsevier, 2019-03-21)
      The study objectives were to determine assessors' (n = 256) preference for corned beef, produced with sequential reductions in NaCl concentrations and to determine if preference was affected by assessor age. The use of a salt replacer such as potassium lactate was also assessed. The youngest age cohort disliked samples containing the highest level of NaCl, whereas the oldest age cohort did not detect differences between samples. The most negatively perceived sample was the control, suggesting that NaCl levels added to commercial corned beef are currently too high for consumer acceptance. All age cohorts, with the exception of the 65–74 age cohort, accepted corned beef samples possessing NaCl levels closest to the FSAI target (1.63 g/100 g). No major sensory differences were noted between samples with and without potassium lactate by the ≥65 age cohort. Potassium lactate may be added to corned beef without affecting sensory attributes, whilst enhancing nutritional content. Assessors of varying age groups have differing preferences for certain NaCl levels and salt replacers.
    • SNP variation in the promoter of the PRKAG3 gene and association with meat quality traits in pig

      Ryan, Marion T; Hamill, Ruth M; O'Halloran, Aisling M; Davey, Grace C; McBryan, Jean; Mullen, Anne Maria; McGee, Chris; Gispert, Marina; Southwood, Olwen I; Sweeney, Torres; et al. (Biomed Central, 25/07/2012)
      Background: The PRKAG3 gene encodes the γ3 subunit of adenosine monophosphate activated protein kinase (AMPK), a protein that plays a key role in energy metabolism in skeletal muscle. Non-synonymous single nucleotide polymorphisms (SNPs) in this gene such as I199V are associated with important pork quality traits. The objective of this study was to investigate the relationship between gene expression of the PRKAG3 gene, SNP variation in the PRKAG3 promoter and meat quality phenotypes in pork. Results: PRKAG3 gene expression was found to correlate with a number of traits relating to glycolytic potential (GP) and intramuscular fat (IMF) in three phenotypically diverse F1 crosses comprising of 31 Large White, 23 Duroc and 32 Pietrain sire breeds. The majority of associations were observed in the Large White cross. There was a significant association between genotype at the g.-311A>G locus and PRKAG3 gene expression in the Large White cross. In the same population, ten novel SNPs were identified within a 1.3 kb region spanning the promoter and from this three major haplotypes were inferred. Two tagging SNPs (g.-995A>G and g.-311A>G) characterised the haplotypes within the promoter region being studied. These two SNPs were subsequently genotyped in larger populations consisting of Large White (n = 98), Duroc (n = 99) and Pietrain (n = 98) purebreds. Four major haplotypes including promoter SNP’s g.-995A>G and g.-311A>G and I199V were inferred. In the Large White breed, HAP1 was associated with IMF% in the M. longissmus thoracis et lumborum (LTL) and driploss%. HAP2 was associated with IMFL% GP-influenced traits pH at 24 hr in LTL (pHULT), pH at 45 min in LTL (pH45LT) and pH at 45 min in the M. semimembranosus muscle (pH45SM). HAP3 was associated with driploss%, pHULT pH45LT and b* Minolta. In the Duroc breed, associations were observed between HAP1 and driploss% and pHUSM. No associations were observed with the remaining haplotypes (HAP2, HAP3 and HAP4) in the Duroc breed. The Pietrain breed was monomorphic in the promoter region. The I199V locus was associated with several GP-influenced traits across all three breeds and IMF% in the Large White and Pietrain breed. No significant difference in promoter function was observed for the three main promoter haplotypes when tested in vitro. Conclusion: Gene expression levels of the porcine PRKAG3 are associated with meat quality phenotypes relating to glycolytic potential and IMF% in the Large White breed, while SNP variation in the promoter region of the gene is associated with PRKAG3 gene expression and meat quality phenotypes.