• Assessment of RNAlater® as a Potential Method to Preserve Bovine Muscle Proteins Compared with Dry Ice in a Proteomic Study

      Zhu, Yao; Mullen, Anne Maria; Rai, Dilip K.; Kelly, Alan L.; Sheehan, David; Cafferky, Jamie; Hamill, Ruth; Teagasc Walsh Fellowship Programme; NFFQ0017 (MDPI, 2019-02-05)
      RNAlater® is regarded as a potential preservation method for proteins, while its effect on bovine muscle proteins has rarely been evaluated. Bovine muscle protein samples (n = 12) collected from three tender (Warner–Bratzler shear force: 30.02–31.74 N) and three tough (Warner–Bratzler shear force: 54.12–66.25 N) Longissimus thoracis et lumborum (LTL) samples, preserved using two different sampling preservation methods (RNAlater® and dry ice), at two post mortem time points (day 0 and day 14), were characterized using one-dimensional electrophoresis. Fourteen bands with molecular weights ranging from 15 to 250 kDa were verified, both in the dry ice and RNAlater® storage groups, at each time point, using image analysis. A shift from high to low molecular weight fragments, between day 0 and day 14, indicated proteolysis of the muscle proteins during post mortem storage. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses and database searching resulted in the identification of 10 proteins in four bands. Protein profiles of muscle preserved in RNAlater® were similar to those of muscle frozen on dry ice storage, both at day 0 and day 14. The results demonstrate that RNAlater® could be a simple and efficient way to preserve bovine muscle proteins for bovine muscle proteomic studies
    • Comparative Proteomic Profiling of Divergent Phenotypes for Water Holding Capacity across the Post Mortem Ageing Period in Porcine Muscle Exudate

      Di Luca, Alessio; Hamill, Ruth; Mullen, Anne Maria; Slavov, Nikolai; Giuliano, Elia; Department of Agriculture, Food and the Marine, Ireland; 06RDNUIG470 (PLOS, 07/03/2016)
      Two dimensional Difference Gel Electrophoresis (2-D DIGE) and mass spectrometry were applied to investigate the changes in metabolic proteins that occur over a seven day (day 1, 3 and 7) post mortem ageing period in porcine centrifugal exudate from divergent meat quality phenotypes. The objectives of the research were to enhance our understanding of the phenotype (water holding capacity) and search for biomarkers of this economically significant pork quality attribute. Major changes in protein abundance across nine phenotype-by-time conditions were observed. Proteomic patterns were dominated by post mortem ageing timepoint. Using a machine learning algorithm (l1-regularized logistic regression), a model was derived with the ability to discriminate between high drip and low drip phenotypes using a subset of 25 proteins with an accuracy of 63%. Models discriminating between divergent phenotypes with accuracy of 72% and 73% were also derived comparing respectively, high drip plus intermediate phenotype (considered as one phenotype) versus low drip and comparing low drip plus intermediate phenotype (considered as one phenotype) versus high drip. In all comparisons, the general classes of discriminatory proteins identified include metabolic enzymes, stress response, transport and structural proteins. In this research we have enhanced our understanding of the protein related processes underpinning this phenotype and provided strong data to work toward development of protein biomarkers for water holding capacity.
    • Effect of Breed and Gender on Meat Quality of M. longissimus thoracis et lumborum Muscle from Crossbred Beef Bulls and Steers

      Cafferky, Jamie; Hamill, Ruth; Allen, Paul; O’Doherty, John V.; Cromie, Andrew; Sweeney, Torres; Department of Agriculture, Food and the Marine; 11/SF/311 (MDPI, 2019-05-21)
      Abstract The objective of this study was to determine whether sire breed and/or castration had an effect on meat quality of M. longissimus thoracis et lumborum (LTL) muscle from crossbred bulls and steers and to investigate the relationship amongst the traits examined. Warner–Bratzler shear force (WBSF), intramuscular fat (IMF)%, cook-loss%, drip-loss%, colour (L*, a*, b*) and ultimate pH (upH) were determined in the LTL muscle from eight beef sire breeds representative of the Irish herd (Aberdeen Angus, Belgian Blue, Charolais, Hereford, Limousin, Parthenaise, Salers and Simmental). The results indicate that IMF%, cook-loss% and drip-loss% were associated with breed (p < 0.05); while WBSF, IMF% and cook-loss% differ between genders (p < 0.05). Steer LTL had a greater IMF% and exhibited reduced WBSF and cook-loss% in comparison to the bull LTL (p < 0.05). This study provides greater insight into how quality traits in beef are influenced by breed and gender and will support the industry to produce beef with consistent eating quality.
    • Genome-wide association analysis and functional annotation of positional candidate genes for feed conversion efficiency and growth rate in pigs

      Horodyska, Justyna; Hamill, Ruth; Varley, Patrick F.; Wimmers, Klaus; European Union; 311794 (PLOS, 12/06/2017)
      Feed conversion efficiency is a measure of how well an animal converts feed into live weight and it is typically expressed as feed conversion ratio (FCR). FCR and related traits like growth rate (e.g. days to 110 kg—D110) are of high interest for animal breeders, farmers and society due to implications on animal performance, feeding costs and environmental sustainability. The objective of this study was to identify genomic regions associated with FCR and D110 in pigs. A total of 952 terminal line boars, showing an individual variation in FCR, were genotyped using 60K SNP-Chips. Markers were tested for associations with estimated breeding values (EBV) for FCR and D110. For FCR, the largest number of associated SNPs was located on chromosomes 4 (30 SNPs), 1 (25 SNPs), X (15 SNPs) and 6 (12 SNPs). The most prominent genomic regions for D110 were identified on chromosomes 15 (10 SNPs), 1 and 4 (both 9 SNPs). The most significantly associated SNPs for FCR and D110 mapped 129.8 Kb from METTL11B (chromosome 4) and 32Kb from MBD5 (chromosome 15), respectively. A list of positional genes, closest to significantly associated SNPs, was used to identify enriched pathways and biological functions related to the QTL for both traits. A number of candidate genes were significantly overrepresented in pathways of immune cell trafficking, lymphoid tissue structure, organ morphology, endocrine system function, lipid metabolism, and energy production. After resequencing the coding region of selected positional and functional candidate genes, six SNPs were genotyped in a subset of boars. SNPs in PRKDC, SELL, NR2E1 and AKRIC3 showed significant associations with EBVs for FCR/D110. The study revealed a number of chromosomal regions and candidate genes affecting FCR/D110 and pointed to corresponding biological pathways related to lipid metabolism, olfactory reception, and also immunological status.
    • Impact on the physical and sensory properties of salt-and fat-reduced traditional Irish breakfast sausages on various age cohorts acceptance

      Conroy, Paula M.; O'Sullivan, Maurice; Hamill, Ruth; Kerry, Joseph; Department of Agriculture, Food and the Marine; 11/F/045 (Elsevier, 2018-05-02)
      The properties of varying salt and fat levels in traditional breakfast sausages were investigated. Sausages were produced with fat levels of: 30%, 20% and 15%. Fat was replaced with pea extract. Salt levels employed were: 2.5%, 1.1% and 0.0%. A reduced sodium salt which contains 45% less sodium than standard salt was used. Sensory analysis was conducted on consumers (n = 228): 18–40 yrs., 41–64 yrs. and 65–85 yrs. The 18–40 yr. olds preferred sausages containing 20% fat, 41–64 yr. olds preferred sausages with 15% fat, 65+ age group preferred sausages containing 30% fat. The 18–40 yr. olds preferred high salt samples, 41–64 yr. olds displayed no salt preference, while the 65+ age group preferred high salt sausages. Sausage formulation choice was found to be driven by texture for the younger age cohort, flavour for the middle age cohort and visual aspects from the oldest age cohort. There is a need to understand how meat products might be reformulated different age palates.
    • Impact on the physicochemical and sensory properties of salt reduced corned beef formulated with and without the use of salt replacers

      Fellendorf, Susann; Kerry, Joseph P.; Hamill, Ruth; O'Sullivan, Maurice G.; Department of Agriculture, Food and the Marine; 11 F 026 (Elsevier, 2018-03-02)
      The aim of this study was to investigate physicochemical and microbiological properties as well as a sensory (affective and descriptive) driven sodium reduction (0.2 g/100 g - 1.0 g/100 g product) strategy for a cured meat product (corned beef). A second aim was to use the same methodology to further reduce salt, using salt replacers. Significant differences in colour, hardness and cooking loss were measured. Corned beef samples low in sodium (0.2 g/100 g, 0.4 g/100 g) showed reduced (P < 0.05) saltiness perception, but were positively correlated (P > 0.05) to liking of flavour and overall acceptability. Samples formulated with CaCl2, MgCl2 and KCl scored higher (P < 0.01) in saltiness perceptions, but correlated negatively (P > 0.05) to liking of flavour and overall acceptability. However, a sodium reduction in corned beef was determined to be achievable as assessors liked (P < 0.05) the flavour of the sodium reduced corned beef containing 0.4 g/100 g sodium and formulated with potassium lactate and glycine (KLG), even with the noticeable lower salty taste. Sodium reduction in corned beef (packaged under modified atmosphere) did not negatively impact on the microbiological shelf-life.
    • In vitro digestion of protein-enriched restructured beef steaks with pea protein isolate, rice protein and lentil flour following sous vide processing

      Baugreet, Sephora; Gomez, Carolina; Auty, Mark; Kerry, Joseph P.; Hamill, Ruth; Brodkorb, Andre; Teagasc Walsh Fellowship Programme; Department of Agriculture, Food and the Marine; 11/F/045 (Elsevier, 2019-04-12)
      The effect of plant protein inclusion in cooked meat upon in vitro gastro-intestinal (GI) digestion was investigated. Pea protein isolate, rice protein and lentil flour were used to increase the protein content in a meat model system restructured using two transglutaminase enzymes [Activa®EB (TG) and Transgluseen™-M (TS)]. Restructured beef steaks were subjected to simulated GI digestion using the static INFOGEST method. Samples taken at different digestion times were analysed using SDS-PAGE, size exclusion-HPLC, free amino acid analysis and microscopy. SDS-PAGE analysis revealed significant protein hydrolysis during GI digestion. Most soluble peptides had a molecular weight smaller than 500 Da, corresponding to peptides of <5 amino acids, regardless of food treatment. The amounts of released, free amino acids isoleucine, lysine, phenylalanine and valine were higher (P < 0.05) in lentil-enriched restructured beef steaks following GI digestion. Confocal laser scanning microscopy (CSLM) revealed pronounced aggregation in digested samples. In vitro digestates of protein-enriched restructured beef steaks showed lower production of small molecular weight peptides. This study demonstrated how the bioaccessibility of protein-enriched restructured beef steaks are influenced by formulation and processing.
    • Interaction of salt content and processing conditions drives the quality response in streaky rashers

      Delgado-Pando, Gonzalo; Allen, Paul; Kerry, Joseph P.; O'Sullivan, Maurice G.; Hamill, Ruth; Department of Agriculture, Food and the Marine; 11F 026 (Elsevier, 2018-07-26)
      Response surface methodology was utilised to explore the relationship between processing conditions, including cooking temperature and drying time, and ingredients in reduced-salt streaky rasher formulations. The goal of this project was to assess the impact of reducing salt content on physicochemical and sensory properties. Salt levels above 2.44 g/100 g did not affect cooking loss. Cooking temperature (240 °C) was negatively correlated with lightness and redness, n-3 fatty acids, and sensory acceptance, and positively correlated with hardness and monounsaturated fatty acids. Salt content was highly correlated with perceived saltiness and both were identified as negative attributes by the sensory panel. Results indicate that optimised reduced-salt streaky rashers with acceptable technological and sensory performance could be achieved under the following conditions: 2 g/100 g salt, 94 min of drying and grilling at 190 °C.
    • Investigating the use of visible and near infrared spectroscopy to predict sensory and texture attributes of beef M. longissimus thoracis et lumborum

      Cafferky, Jamie; Sweeney, Torres; Allen, Paul; Sahar, Amna; Downey, Gerard; Cromie, A. R.; Hamill, Ruth; Department of Agriculture, Food and the Marine; 11/SF/311 (Elsevier, 2019-08-16)
      The aim of this study was to calibrate chemometric models to predict beef M. longissimus thoracis et lumborum (LTL) sensory and textural values using visible-near infrared (VISNIR) spectroscopy. Spectra were collected on the cut surface of LTL steaks both on-line and off-line. Cooked LTL steaks were analysed by a trained beef sensory panel as well as undergoing WBSF analysis. The best coefficients of determination of cross validation (R2CV) in the current study were for textural traits (WBSF = 0.22; stringiness = 0.22; crumbly texture = 0.41: all 3 models calibrated using 48 h post-mortem spectra), and some sensory flavour traits (fatty mouthfeel = 0.23; fatty after-effect = 0.28: both calibrated using 49 h post-mortem spectra). The results of this experiment indicate that VISNIR spectroscopy has potential to predict a range of sensory traits (particularly textural traits) with an acceptable level of accuracy at specific post-mortem times.
    • Online Prediction of Physico-Chemical Quality Attributes of Beef Using Visible—Near-Infrared Spectroscopy and Chemometrics

      Sahar, Amna; Allen, Paul; Sweeney, Torres; Cafferky, Jamie; Downey, Gerard; Cromie, Andrew; Hamill, Ruth; Department of Food, Agriculture and the Marine; 11/SF/311 (MDPI AG, 2019-10-23)
      The potential of visible–near-infrared (Vis–NIR) spectroscopy to predict physico-chemical quality traits in 368 samples of bovine musculus longissimus thoracis et lumborum (LTL) was evaluated. A fibre-optic probe was applied on the exposed surface of the bovine carcass for the collection of spectra, including the neck and rump (1 h and 2 h post-mortem and after quartering, i.e., 24 h and 25 h post-mortem) and the boned-out LTL muscle (48 h and 49 h post-mortem). In parallel, reference analysis for physico-chemical parameters of beef quality including ultimate pH, colour (L, a*, b*), cook loss and drip loss was conducted using standard laboratory methods. Partial least-squares (PLS) regression models were used to correlate the spectral information with reference quality parameters of beef muscle. Different mathematical pre-treatments and their combinations were applied to improve the model accuracy, which was evaluated on the basis of the coefficient of determination of calibration (R2C) and cross-validation (R2CV) and root-mean-square error of calibration (RMSEC) and cross-validation (RMSECV). Reliable cross-validation models were achieved for ultimate pH (R2CV: 0.91 (quartering, 24 h) and R2CV: 0.96 (LTL muscle, 48 h)) and drip loss (R2CV: 0.82 (quartering, 24 h) and R2CV: 0.99 (LTL muscle, 48 h)) with lower RMSECV values. The results show the potential of Vis–NIR spectroscopy for online prediction of certain quality parameters of beef over different time periods.
    • Optimisation of plant protein and transglutaminase content in novel beef restructured steaks for older adults by central composite design

      Baugreet, Sephora; Kerry, Joseph P.; Brodkorb, Andre; Gomez, Carolina; Auty, Mark; Allen, Paul; Hamill, Ruth; Department of Agriculture, Food and the Marine, Ireland; Teagasc Walsh Fellowship Programme; 11/F/045 (Elsevier, 2018-03-29)
      With the goal of optimising a protein-enriched restructured beef steak targeted at the nutritional and chemosensory requirements of older adults, technological performance of thirty formulations, containing plant-based ingredients, pea protein isolate (PPI), rice protein (RP) and lentil flour (LF) with transglutaminase (TG) to enhance binding of meat pieces, were analysed. Maximal protein content of 28% in cooked product was achieved with PPI, RP and LF. Binding strength was primarily affected by TG, while textural parameters were improved with LF inclusion. Optimal formulation (F) to obtain a protein-enriched steak with lowest hardness values was achieved with TG (2%), PPI (8%), RP (9.35%) and LF (4%). F, F1S (optimal formulation 1 with added seasoning) and control restructured products (not containing plant proteins or seasonings) were scored by 120 consumers' aged over-65 years. Controls were most preferred (P < .05), while F1S were least liked by the older consumers. Consumer testing suggests further refinement and optimisation of restructured products with plant proteins should be undertaken.
    • Optimisation of plant protein and transglutaminase content in novel beef restructured steaks for older adults by central composite design

      Baugreet, Sephora; Kerry, Joesph; Brodkorb, Andre; Gomez, Carolina; Auty, Mark; Allen, Paul; Hamill, Ruth; Teagasc Walsh Fellowship Programme; Department of Agriculture, Food and the Marine; 11/F/045 (Elsevier, 2018-03-29)
      With the goal of optimising a protein-enriched restructured beef steak targeted at the nutritional and chemosensory requirements of older adults, technological performance of thirty formulations, containing plant-based ingredients, pea protein isolate (PPI), rice protein (RP) and lentil flour (LF) with transglutaminase (TG) to enhance binding of meat pieces, were analysed. Maximal protein content of 28% in cooked product was achieved with PPI, RP and LF. Binding strength was primarily affected by TG, while textural parameters were improved with LF inclusion. Optimal formulation (F) to obtain a protein-enriched steak with lowest hardness values was achieved with TG (2%), PPI (8%), RP (9.35%) and LF (4%). F, F1S (optimal formulation 1 with added seasoning) and control restructured products (not containing plant proteins or seasonings) were scored by 120 consumers' aged over-65 years. Controls were most preferred (P < .05), while F1S were least liked by the older consumers. Consumer testing suggests further refinement and optimisation of restructured products with plant proteins should be undertaken.
    • Optimising the acceptability of reduced-salt ham with flavourings using a mixture design

      Delgado-Pando, Gonzalo; Allen, Paul; Kerry, Joseph P.; O'Sullivan, Maurice; Hamill, Ruth; Department of Agriculture, Food and the Marine; 11F 026 (Elsevier, 2019-05-13)
      The objective of this study was to optimise the acceptability of reduced-salt cooked ham containing a mixture of glycine and yeast extract as flavourings by using response surface methodology. Twelve different formulations were prepared with varying levels of salt and the two flavourings, according to a mixture design. The sensory properties were assessed along with the instrumental texture and colour. A multiple factor analysis showed that higher scores in tenderness, saltiness and juiciness were positively correlated, whereas instrumental hardness and chewiness were negatively correlated with acceptability. Response surface plots and optimisation software allowed the inference of two optimised formulations: HO1 with 1.3% salt and yeast extract content of 0.33%; and HO2 with 1.27% salt, 0.2% yeast extract and 0.16% glycine. A panel of 100 consumers found no significant differences in overall acceptability when both were compared to a control (1.63% salt). These results show it is possible to manufacture consumer accepted cooked ham with up to 20% salt reduction.
    • 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.
    • 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.