• 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
    • Brans of the roller-milled barley fractions rich in polyphenols and health-promoting lipophilic molecules

      Gangopadhyay, Nirupama; Harrison, Sabine M; Brunton, Nigel P; Hidalgo-Ruiz, José L; Gallagher, Eimear; Rai, Dilip K.; Department of Agriculture, Food and the Marine; 11/SF/317 (Elsevier, 2018-09-01)
      Three different roller-milled fractions namely bran, middlings, and flour of five commonly grown Irish barley varieties were investigated for the presence of β-glucan, polyphenols, and health-promoting lipophilic molecules. β-glucan was predominantly located in barley middlings. Polyphenols, as indicated by total phenolic content and the antioxidant activities, were abundant in the outermost bran fractions of barley. Similarly the health-promoting lipophilic molecules including phytosterols, unsaturated fatty acids, and tocols were most abundant in the barley bran fraction. However, the distribution of individual polyphenols and lipophilic compounds varied within the grain; for example ferulic acid and procyainidin C were not detected in flour fraction. Principal component analysis (PCA) clearly indicated a higher distribution of most bioactive molecules in bran as compared to middlings and flour fractions. The PCA also established possible correlations between the five barley varieties and their fractions based on their clustering in the plot.
    • Dietary Compounds Influencing the Sensorial, Volatile and Phytochemical Properties of Bovine Milk

      Clarke, Holly J.; Griffin, Carol; Rai, Dilip K.; O’Callaghan, Tom F.; O’Sullivan, Maurice G.; Kerry, Joseph P.; Kilcawley, Kieran N.; Teagasc Walsh Fellowship Programme; 2016071 (MDPI AG, 2019-12-19)
      The main aim of this study was to evaluate the volatile profile, sensory perception, and phytochemical content of bovine milk produced from cows fed on three distinct feeding systems, namely grass (GRS), grass/clover (CLV), and total mixed ration (TMR). Previous studies have identified that feed type can influence the sensory perception of milk directly via the transfer of volatile aromatic compounds, or indirectly by the transfer of non-volatile substrates that act as precursors for volatile compounds. In the present study, significant differences were observed in the phytochemical profile of the different feed and milk samples. The isoflavone formonoetin was significantly higher in CLV feed samples, but higher in raw GRS milk, while other smaller isoflavones, such as daidzein, genistein, and apigenin were highly correlated to raw CLV milk. This suggests that changes in isoflavone content and concentration in milk relate to diet, but also to metabolism in the rumen. This study also found unique potential volatile biomarkers in milk (dimethyl sulfone) related to feeding systems, or significant differences in the concentration of others (toluene, p-cresol, ethyl and methyl esters) based on feeding systems. TMR milk scored significantly higher for hay-like flavor and white color, while GRS and CLV milk scored significantly higher for a creamy color. Milk samples were easily distinguishable by their volatile profile based on feeding system, storage time, and pasteurization.
    • Fate of beta-glucan, polyphenols and lipophilic compounds in baked crackers fortified with different barley-milled fractions

      Gangopadhyay, Nirupama; O'Shea, Norah; Brunton, Nigel P.; Gallagher, Eimear; Harrison, Sabine M.; Rai, Dilip K.; Department of Agriculture, Food and the Marine; FIRM 11/SF/317 (Elsevier BV, 2019-07-18)
      Four types of crackers were prepared, whereby wheat flour was substituted with different percentages of barley flour and bran. These formulations were compared to a 100% wheat flour (control) cracker with respect to β-glucan, polyphenols and lipophilic bioactives. Incorporation of barley fractions enriched the β-glucan, and phenolic content, as well as in vitro antioxidant capacities of the crackers. However, some polyphenols including procyanidin C and ferulic acid could not be detected in the crackers owing to the probable degradation of these compounds during baking. The β-glucan, flavanols (catechin and procyanidin B), as well as fatty acids and sterols were least affected; while the α-tocotrienols showed degradation following the baking process. Overall, barley fractions can serve as valued ingredients for enhancing the health-salutary components of fortified crackers or the products thereof.
    • Observations on the water distribution and extractable sugar content in carrot slices after pulsed electric field treatment

      Aguilo-Aguayo, Ingrid; Downey, Gerard; Keenan, Derek F.; Lyng, James G.; Brunton, Nigel; Rai, Dilip K.; Department of Agriculture, Food and the Marine; Generalitat of Catalonia; Lifelong Learning Programme; FIRM 06/TNI/AFRC6; et al. (Elsevier, 13/06/2014)
      The impact of pulsed electric field (PEF) processing conditions on the distribution of water in carrot tissue and extractability of soluble sugars from carrot slices was studied. Time domain NMR relaxometry was used to investigate the water proton mobility in PEF-treated carrot samples. Three distinct transverse relaxation peaks were observed in untreated carrots. After PEF treatment only two slightly-overlapping peaks were found; these were attributed to water present in the cytoplasm and vacuole of carrot xylem and phloem tissues. This post-treatment observation indicated an increase in water permeability of tissues and/or a loss of integrity in the tonoplast. In general, the stronger the electric field applied, the lower the area representing transverse relaxation (T2) values irrespective of treatment duration. Moreover an increase in sucrose, β- and α-glucose and fructose concentrations of carrot slice extracts after PEF treatment suggested increases in both cell wall and vacuole permeability as a result of exposure to pulsed electric fields.