• Qualitative and Quantitative Analysis of Polyphenols in Lamiaceae Plants—A Review

      Tzima, Katerina; Brunton, Nigel P.; Rai, Dilip K.; Teagasc Walsh Fellowship Programme; 2016038 (MDPI, 2018-03-26)
      Lamiaceae species are promising potential sources of natural antioxidants, owing to their high polyphenol content. In addition, increasing scientific and epidemiological evidence have associated consumption of foods rich in polyphenols with health benefits such as decreased risk of cardiovascular diseases mediated through anti-inflammatory effects. The complex and diverse nature of polyphenols and the huge variation in their levels in commonly consumed herbs make their analysis challenging. Innovative robust analytical tools are constantly developing to meet these challenges. In this review, we present advances in the state of the art for the identification and quantification of polyphenols in Lamiaceae species. Novel chromatographic techniques that have been employed in the past decades are discussed, ranging from ultra-high-pressure liquid chromatography to hyphenated spectroscopic methods, whereas performance characteristics such as selectivity and specificity are also summarized.
    • The quality of under-utilised deep-water fish species

      Brennan, Martine H.; Gormley, Ronan T.; European Union; Marine Research Measure (Teagasc, 1999-09)
      The quality of twenty-three frozen under-utilised fish species was examined. The species were spot samples of deep-water fish caught near the Rockall Trough by the Fisheries Research Centre. Their basic composition was 80.8 - 86.4% water, 9.8 - 25.2% protein, 0.18 - 16.2% lipid and 0.7 - 2.0% ash. Lead, cadmium and mercury concentrations were determined for six species and were much lower than the maximum levels set in 1992. Ammonia levels were unacceptably high in three shark species.
    • A quantitative risk assessment of E.coli 0157:H7 in Irish minced beef

      Duffy, Geraldine; O'Brien, Stephen; Carney, Eimear; Butler, Francis; Cummins, Enda; Nally, Padraig; Mahon, Denise; Henchion, Maeve; Cowan, Cathal (Teagasc, 2005-02)
      A national quantitative risk assessment was undertaken for minced beef in the Republic of Ireland. The objective was to estimate the probability of E. coli O157:H7 infection from consumption of Irish beef and to investigate the parts of the beef chain contributing most to the risk posed by this pathogen.The quantitative risk assessment was broken into 3 main modules: 1) production of boxed beef trimmings; 2) processing of trimmings and burger formation and 3) retail/domestic consumption phase. Key points in each module (beef hide, beef trimmings and beef products at retail) were validated using data derived from microbiology sampling at beef abattoirs, supermarkets and butchers’ shops in Ireland.
    • Rapid control systems for veterinary drug residues in food producing animals

      O'Keeffe, Michael; European Union; SMT4 - CT96 - 2092 (Teagasc, 2002-10)
      The aim was to develop rapid systems which could be used to test for the presence of veterinary drug residues in food producing animals. Body fluid samples are most suitable for rapid testing systems so as to avoid the lengthy residue extraction procedures required for tissue samples. Urine was analysed for sulphamethazine, a licensed antimicrobial, and for chlorotestosterone, a prohibited growth promoting agent, as models to demonstrate the different approaches.
    • Rapid cooling of cooked meat joints

      Kenny, Tony; Desmond, Eoin; Ward, Patrick; Sun, Da-Wen (Teagasc, 2002-02)
      Conventional cooling by air-blast or even by immersion in liquid is unlikely to achieve recommended cooling rates when dealing with joints weighing 5kg or more because meat has a low thermal conductivity. The objective was to investigate vacuum cooling as a technique for rapid chilling of cooked meat joints. In vacuum cooling, the food is enclosed in a chamber and reduction of the pressure to about 7 mbar causes evaporation of water from the surface of the food and from cavities in the food. The energy required to evaporate the water is extracted from the food, resulting in rapid chilling
    • Recent advances in the application of pulsed light processing for improving food safety and increasing shelf life

      Mahendran, Radhakrishnan; Ratish Ramanan, K.; Barba, Francisco J.; Lorenzo, Jose M.; López-Fernández, Olalla; Munekata, Paulo E. S.; Roohinejad, Shahin; Sant'Ana, Anderson S.; Tiwari, Brijesh; National Council for Scientific and Technological Development; et al. (Elsevier, 2019-03-18)
      Background New technologies of non-thermal disinfection such as pulsed light (PL) have emerged lately as an alternative to traditional (thermal and chemical) disinfection and preservation methods. PL can be used to decontaminate a great variety of foods as well as to decontaminate contact surfaces, thus improving safety in foods and extending their shelf life. Moreover, this technology can prevent or reduce some of the detrimental effects of traditional methods on nutrients and bioactive compounds of food products. Scope and approach The combination of PL with other techniques such as ultraviolet light (UV), thermosonication (TS), pulsed electric fields (PEF), manothermosonication (MTS), etc., can improve the effectiveness of the decontamination process. Therefore, in this review, some of the most relevant studies evaluating the potential application of PL treatments to decontaminate food samples, and its impact of nutritional and physicochemical quality parameters will be discussed. Key findings and conclusions PL treatments are suitable for microbial decontamination in transparent drinks and for surface contaminated foods without complex microstructures. They also can be used for meat, fish and their by-products However, it is still necessary to evaluate the appropriate treatment conditions (number of light flashed, voltage, distance between sample and flash light, spectral range of light flashes and contamination) for each food and microorganism separately to improve the effectiveness and minimize the appearance of negative attributes reducing the quality of product as, in some cases, PL can have a negative effect on the photosensitive compounds and sensory characteristics of food products.
    • Recombinant Incretin-Secreting Microbe Improves Metabolic Dysfunction in High-Fat Diet Fed Rodents

      Ryan, Paul M; Patterson, Elaine; Kent, Robert M.; Stack, Helena; O’Connor, Paula M.; Murphy, Kiera; Peterson, Veronica L.; Mandal, Rupasri; Wishart, David S.; Dinan, Timothy G.; et al. (Springer Nature, 2017-10-19)
      The gut hormone glucagon-like peptide (GLP)-1 and its analogues represent a new generation of anti-diabetic drugs, which have also demonstrated propensity to modulate host lipid metabolism. Despite this, drugs of this nature are currently limited to intramuscular administration routes due to intestinal degradation. The aim of this study was to design a recombinant microbial delivery vector for a GLP-1 analogue and assess the efficacy of the therapeutic in improving host glucose, lipid and cholesterol metabolism in diet induced obese rodents. Diet-induced obese animals received either Lactobacillus paracasei NFBC 338 transformed to express a long-acting analogue of GLP-1 or the isogenic control microbe which solely harbored the pNZ44 plasmid. Short-term GLP-1 microbe intervention in rats reduced serum low-density lipoprotein cholesterol, triglycerides and triglyceride-rich lipoprotein cholesterol substantially. Conversely, extended GLP-1 microbe intervention improved glucose-dependent insulin secretion, glucose metabolism and cholesterol metabolism, compared to the high-fat control group. Interestingly, the microbe significantly attenuated the adiposity associated with the model and altered the serum lipidome, independently of GLP-1 secretion. These data indicate that recombinant incretin-secreting microbes may offer a novel and safe means of managing cholesterol metabolism and diet induced dyslipidaemia, as well as insulin sensitivity in metabolic dysfunction.
    • Recovery and identification of emerging Campylobacteraceae from food

      Duffy, Geraldine; Cagney, Claire; Lynch, Orla; Downey, Gerard (Teagasc, 01/02/2007)
      The family Campylobacteraceae includes 23 different species of Campylobacter and Arcobacter.To date, clinical and epidemiological interest has focused almost exclusively on just two of these species, C. jejuni and C. coli. Current routine examination methods for both clinical and food samples look exclusively for these two species. Recent clinical research indicates that some of the other, previously ignored Campylobacter species may be linked to human infection. The focus of this research was to develop a routine procedure which would allow recovery of all 23 species of Campylobacteraceae from food samples.
    • Recovery and identification of emerging campylobacteraceae from food

      Duffy, Geraldine; Cagney, Claire; Lynch, Orla (Teagasc, 2007-02)
      The family Campylobacteraceae includes 23 different species of Campylobacter and Arcobacter.To date, clinical and epidemiological interest has focused almost exclusively on just two of these species, C. jejuni and C. coli. Current routine examination methods for both clinical and food samples look exclusively for these two species. Recent clinical research indicates that some of the other, previously ignored Campylobacter species may be linked to human infection. The focus of this research was to develop a routine procedure which would allow recovery of all 23 species of Campylobacteraceae from food samples.
    • Recovery of Polyphenols from Brewer’s Spent Grains

      Birsan, Rares; Wilde, Peter; Waldron, Keith; Rai, Dilip K.; Teagasc Walsh Fellowship Programme; 2014027 (MDPI, 2019-09-07)
      The recovery of antioxidant polyphenols from light, dark and mix brewer’s spent grain (BSG) using conventional maceration, microwave and ultrasound assisted extraction was investigated. Total polyphenols were measured in the crude (60% acetone), liquor extracts (saponified with 0.75% NaOH) and in their acidified ethyl acetate (EtOAc) partitioned fractions both by spectrophotometry involving Folin–Ciocalteu reagent and liquid-chromatography-tandem mass spectrometry (LC-MS/MS) methods. Irrespective of the extraction methods used, saponification of BSG yielded higher polyphenols than in the crude extracts. The EtOAc fractionations yielded the highest total phenolic content (TPC) ranging from 3.01 ± 0.19 to 4.71 ± 0.28 mg gallic acid equivalent per g of BSG dry weight. The corresponding total polyphenols quantified by LC-MS/MS ranged from 549.9 ± 41.5 to 2741.1 ± 5.2 µg/g of BSG dry weight. Microwave and ultrasound with the parameters and equipment used did not improve the total polyphenol yield when compared to the conventional maceration method. Furthermore, the spectrophotometric quantification of the liquors overestimated the TPC, while the LC-MS/MS quantification gave a closer representation of the total polyphenols in all the extracts. The total polyphenols were in the following order in the EtOAc fractions: BSG light > BSG Mix > BSG dark, and thus suggested BSG light as a sustainable, low cost source of natural antioxidants that may be tapped for applications in food and phytopharmaceutical industries.
    • Recovery of Polyphenols from Brewer’s Spent Grains

      Birsan, Rares I.; Wilde, Peter; Waldron, Keith W.; Rai, Dilip K.; Teagasc Walsh Fellowship Programme; 2014027 (MDPI AG, 2019-09-07)
      The recovery of antioxidant polyphenols from light, dark and mix brewer’s spent grain (BSG) using conventional maceration, microwave and ultrasound assisted extraction was investigated. Total polyphenols were measured in the crude (60% acetone), liquor extracts (saponified with 0.75% NaOH) and in their acidified ethyl acetate (EtOAc) partitioned fractions both by spectrophotometry involving Folin–Ciocalteu reagent and liquid-chromatography-tandem mass spectrometry (LC-MS/MS) methods. Irrespective of the extraction methods used, saponification of BSG yielded higher polyphenols than in the crude extracts. The EtOAc fractionations yielded the highest total phenolic content (TPC) ranging from 3.01 ± 0.19 to 4.71 ± 0.28 mg gallic acid equivalent per g of BSG dry weight. The corresponding total polyphenols quantified by LC-MS/MS ranged from 549.9 ± 41.5 to 2741.1 ± 5.2 µg/g of BSG dry weight. Microwave and ultrasound with the parameters and equipment used did not improve the total polyphenol yield when compared to the conventional maceration method. Furthermore, the spectrophotometric quantification of the liquors overestimated the TPC, while the LC-MS/MS quantification gave a closer representation of the total polyphenols in all the extracts. The total polyphenols were in the following order in the EtOAc fractions: BSG light > BSG Mix > BSG dark, and thus suggested BSG light as a sustainable, low cost source of natural antioxidants that may be tapped for applications in food and phytopharmaceutical industries
    • Recovery of Steroidal Alkaloids from Potato Peels Using Pressurized Liquid Extraction

      Rawson, Ashish; Aguiló-Aguayo, Ingrid; Brunton, Nigel; Hossain, Mohammad B; Rai, Dilip K.; Department of Agriculture, Food and the Marine; 08/RD/AFRC/673 (MDPI, 2015-05-13)
      A higher yield of glycoalkaloids was recovered from potato peels using pressurized liquid extraction (1.92 mg/g dried potato peels) compared to conventional solid–liquid extraction (0.981 mg/g dried potato peels). Response surface methodology deduced the optimal temperature and extracting solvent (methanol) for the pressurized liquid extraction (PLE) of glycoalkaloids as 80 °C in 89% methanol. Using these two optimum PLE conditions, levels of individual steroidal alkaloids obtained were of 597, 873, 374 and 75 µg/g dried potato peel for α-solanine, α-chaconine, solanidine and demissidine respectively. Corresponding values for solid liquid extraction were 59%, 46%, 40% and 52% lower for α-solanine, α-chaconine, solanidine and demissidine respectively
    • Redefining the effect of salt on thermophilic starter cell viability, culturability and metabolic activity in cheese

      Hickey, Cian D; Fallico, Vincenzo; Wilkinson, M.G.; Sheehan, Jeremiah J.; Dairy Levy Trust; 6259 (Elsevier, 2017-08-23)
      This study investigated the differential effect of salt concentration in the outside and inside layers of brine salted cheeses on viability, culturability and enzyme activity of starter bacteria. The high-salt environment of the outside layer caused a sharp decrease in L. helveticus viability as measured by traditional plate counts. Remarkably, this was associated with lower release of intracellular enzymes (LDH), reduced levels of proteolysis and larger membrane integrity as measured by flow cytometry (FC) following classical Live/Dead staining. FC analysis of light scattering properties highlighted a significant reduction in size and granularity of the microbiota located in the cheese surface, suggestive of cell shrinkage and condensation of internal macromolecules probably due to hyperosmotic stress. The microbiota of the cheese surface were found to experience greater oxidative stress, as measured by FC analysis of the total levels of reactive oxygen species, compared to that of the interior layer. These results lead us to postulate that the physiology and health status of the microbiota were significantly different in the outer and inner layers of the cheese. The hyperosmotic environment of the outer layer resulted in reduced cell lysis, as measurable by assays based upon membrane integrity, but rather triggered cell death via mechanisms involving cell shrinkage and ROS-mediated damage of vital intracellular components. This study challenges the current thinking on how salt controls microbial activity in ripening cheese, especially in cheeses which are brine salted as local variations in biochemical ripening indices can differ significantly from the outside to the inside of a ripening cheese.
    • 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.
    • Regulation of intestinal growth in response to variations in energy supply and demand

      Nilaweera, Kanishka N.; Speakman, John R.; Science Foundation Ireland; Biotechnology and Biological Sciences Research Council (BBSRC); SFI/16/BBSRC/3389; BB/P009875/1 (Wiley, 2018-12-03)
      The growth of the intestine requires energy, which is known to be met by catabolism of ingested nutrients. Paradoxically, during whole body energy deficit including calorie restriction, the intestine grows in size. To understand how and why this happens, we reviewed data from several animal models of energetic challenge. These were bariatric surgery, cold exposure, lactation, dietary whey protein intake and calorie restriction. Notably, these challenges all reduced the adipose tissue mass, altered hypothalamic neuropeptide expression and increased intestinal size. Based on these data, we propose that the loss of energy in the adipose tissue promotes the growth of the intestine via a signalling mechanism involving the hypothalamus. We discuss possible candidates in this pathway including data showing a correlative change in intestinal (ileal) expression of the cyclin D1 gene with adipose tissue mass, adipose derived‐hormone leptin and hypothalamic expression of leptin receptor and the pro‐opiomelanocortin gene. The ability of the intestine to grow in size during depletion of energy stores provides a mechanism to maximize assimilation of ingested energy and in turn sustain critical functions of tissues important for survival.
    • 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.
    • Rehydration behaviour of spray-dried micellar casein concentrates produced using microfiltration of skim milk at cold or warm temperatures

      Crowley, Shane V.; Burlot, Esther; Silva, Juliana V.C.; McCarthy, Noel A.; Wijayanti, Heni B.; Fenelon, Mark A.; Kelly, Alan L.; O'Mahony, James A.; Department of Agriculture, Food and the Marine; Enterprise Ireland; et al. (Elsevier, 2018-02-02)
      Microfiltration (MF) of skim milk, when combined with diafiltration (DF), facilitates the manufacture of liquid micellar casein concentrate (MCC), which can be spray-dried into high-protein (≥80% protein, dry-basis) powders. MCC powders rehydrate slowly, which is typically considered a defect by end-users. This study compared the impact of cold (<10 °C) or warm (50 °C) MF/DF on the rehydration characteristics of MCC powders (MCCcold and MCCwarm, respectively). The wetting properties of the MCC powders, measured using optical tensiometry, were found to be equivalent. However, pronounced differences in dispersion characteristics were measured, and, after 90 min rehydration at 50 °C, liberated casein micelles accounted for only 7.5% of total particle volume in MCCwarm compared with 48% in MCCcold. Due to its superior dispersion characteristics, MCCcold yielded 50–60% less sediment during analytical centrifugation experiments. Cold MF/DF may improve the solubility of MCC powders by accelerating the release of casein micelles from powder particles during rehydration.
    • Reincarnation of Bacteriocins From the Lactobacillus Pangenomic Graveyard

      Collins, Fergus W. J.; Mesa-Pereira, Beatriz; O'Connor, Paula M.; Rea, Mary C.; Hill, Colin; Ross, R Paul; Science Foundation Ireland; SFI/12/RC/227 (Frontiers, 2018-07-02)
      Bacteria commonly produce narrow spectrum bacteriocins as a means of inhibiting closely related species competing for similar resources in an environment. The increasing availability of genomic data means that it is becoming easier to identify bacteriocins encoded within genomes. Often, however, the presence of bacteriocin genes in a strain does not always translate into biological antimicrobial activity. For example, when analysing the Lactobacillus pangenome we identified strains encoding ten pediocin-like bacteriocin structural genes which failed to display inhibitory activity. Nine of these bacteriocins were novel whilst one was identified as the previously characterized bacteriocin “penocin A.” The composition of these bacteriocin operons varied between strains, often with key components missing which are required for bacteriocin production, such as dedicated bacteriocin transporters and accessory proteins. In an effort to functionally express these bacteriocins, the structural genes for the ten pediocin homologs were cloned alongside the dedicated pediocin PA-1 transporter in both Escherichia coli and Lactobacillus paracasei heterologous hosts. Each bacteriocin was cloned with its native leader sequence and as a fusion protein with the pediocin PA-1 leader sequence. Several of these bacteriocins displayed a broader spectrum of inhibition than the original pediocin PA-1. We show how potentially valuable bacteriocins can easily be “reincarnated” from in silico data and produced in vitro despite often lacking the necessary accompanying machinery. Moreover, the study demonstrates how genomic datasets such as the Lactobacilus pangenome harbor a potential “arsenal” of antimicrobial activity with the possibility of being activated when expressed in more genetically amenable hosts.
    • Reincarnation of Bacteriocins From the Lactobacillus Pangenomic Graveyard

      Collins, Fergus W. J.; Mesa-Pereira, Beatriz; O'Connor, Paula M.; Rea, Mary C.; Hill, Colin; Ross, R Paul; Science Foundation Ireland; SFI/12/RC/227 (Frontiers, 02/07/2018)
      Bacteria commonly produce narrow spectrum bacteriocins as a means of inhibiting closely related species competing for similar resources in an environment. The increasing availability of genomic data means that it is becoming easier to identify bacteriocins encoded within genomes. Often, however, the presence of bacteriocin genes in a strain does not always translate into biological antimicrobial activity. For example, when analysing the Lactobacillus pangenome we identified strains encoding ten pediocin-like bacteriocin structural genes which failed to display inhibitory activity. Nine of these bacteriocins were novel whilst one was identified as the previously characterized bacteriocin “penocin A.” The composition of these bacteriocin operons varied between strains, often with key components missing which are required for bacteriocin production, such as dedicated bacteriocin transporters and accessory proteins. In an effort to functionally express these bacteriocins, the structural genes for the ten pediocin homologs were cloned alongside the dedicated pediocin PA-1 transporter in both Escherichia coli and Lactobacillus paracasei heterologous hosts. Each bacteriocin was cloned with its native leader sequence and as a fusion protein with the pediocin PA-1 leader sequence. Several of these bacteriocins displayed a broader spectrum of inhibition than the original pediocin PA-1. We show how potentially valuable bacteriocins can easily be “reincarnated” from in silico data and produced in vitro despite often lacking the necessary accompanying machinery. Moreover, the study demonstrates how genomic datasets such as the Lactobacilus pangenome harbor a potential “arsenal” of antimicrobial activity with the possibility of being activated when expressed in more genetically amenable hosts.
    • Relatedness between the two-component lantibiotics lacticin 3147 and staphylococcin C55 based on structure, genetics and biological activity

      O'Connor, Eileen B; Cotter, Paul D.; O'Connor, Paula M.; O'Sullivan, Orla; Tagg, John R; Ross, R Paul; Hill, Colin (Biomed Central, 02/04/2007)
      Background: Two component lantibiotics, such as the plasmid-encoded lacticin 3147 produced by Lactococcus lactis DPC3147 and staphylococcin C55 produced by Staphylococcus aureus C55, represent an emerging subgroup of bacteriocins. These two bacteriocins are particularly closely related, exhibiting 86% (LtnA1 and C55α) and 55% (LtnA2 and C55β) identity in their component peptides. The aim of this study was to investigate, for the first time for any two component bacteriocins, the significance of the relatedness between these two systems. Results: So close is this relatedness that the hybrid peptide pairs LtnA1:C55β and C55α:LtnA2 were found to have activities in the single nanomolar range, comparing well with the native pairings. To determine whether this flexibility extended to the associated post-translational modification/processing machinery, the staphylococcin C55 structural genes were directly substituted for their lacticin 3147 counterparts in the ltn operon on the large conjugative lactococcal plasmid pMRC01. It was established that the lacticin LtnA1 post-translational and processing machinery could produce functionally active C55α, but not C55β. In order to investigate in closer detail the significance of the differences between LtnA1 and C55α, three residues in LtnA1 were replaced with the equivalent residues in C55α. Surprisingly, one such mutant LtnA1-Leu21Ala was not produced. This may be significant given the positioning of this residue in a putative lipid II binding loop. Conclusion: It is apparent, despite sharing striking similarities in terms of structure and activity, that these two complex bacteriocins display some highly dedicated features particular to either system.