K Galvin

University College Cork, Corcaigh, Munster, Ireland

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Publications (29)72.82 Total impact

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    ABSTRACT: 24,25-Dihydroxyvitamin D [24,25(OH)2D] in serum may be both a nuisance and nutritionally valuable. We investigated the impact of 24,25(OH)2D3 on the performance of commercially available immunoassays for serum total 25-hydroxyvitamin D [25(OH)D] using (a) serum from a nationally representative sample of adults, (b) serum from a spiking experiment, and (c) data from the UK Vitamin D External Quality Assurance Scheme (DEQAS). We also investigated the utility of the serum ratio of 24,25(OH)2D3 to 25(OH)D as an index of inactivation and of response to vitamin D supplementation using randomized controlled trial (RCT) data. Measurement of 24,25(OH)2D in sera by a LC-MS/MS method allowed for an investigation of its impact on immunoassay-derived serum 25(OH)D values as well as its clinical utility. We report data from a nationally representative sample of adults, a recent vitamin D RCT in older adults, and DEQAS. 24,25(OH)2D3 contributed to the positive bias observed in some immunoassays relative to LC-MS/MS-derived estimates for total 25(OH)D. A spiking experiment showed that the degree of cross-reactivity with 24, 25(OH)2D was high and may underpin this positive bias. Adjustment for 24,25(OH)2D3 concentration brought estimates closer to true values. Data from the vitamin D RCT showed that the ratio of 24,25(OH)2D3 to 25(OH)D was associated with serum 25(OH)D3 and with response of serum 25(OH)D to vitamin D supplementation. Our findings highlight that the effect of 24,25(OH)2D3 in serum is a double-edged sword-an interferent for some immunoassays, yet potentially informative of nutritional status. © 2015 American Association for Clinical Chemistry.
    Clinical Chemistry 02/2015; 61(4). DOI:10.1373/clinchem.2014.234955 · 7.77 Impact Factor
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    ABSTRACT: Interactions between calcium and vitamin D may have implications for the regulation of serum 25-hydroxyvitamin D [25(OH)D] and its catabolism and, consequently, the vitamin D dietary requirement. We investigated whether different calcium intakes influenced serum 25(OH)D and indexes of vitamin D activation and catabolism during winter and in the context of both adequate and inadequate vitamin D intakes. A 15-wk winter-based, randomized, placebo-controlled, double-blind vitamin D3 intervention (20 μg/d) study was carried out in free-living men and women aged ≥50 y (n = 125) who were stratified according to calcium intakes (moderate-low [<700 mg/d] or high [>1000 mg/d] intake). The serum 25(OH)D concentration was the primary outcome, and serum calcium, parathyroid hormone (PTH), 1,25-dihydroxyvitamin D [1,25(OH)2D], 24,25-dihydroxyvitamin D [24,25(OH)2D], the ratio of 24,25(OH)2D:25(OH)D, vitamin D-binding protein, and free 25(OH)D were exploratory outcomes. A repeated-measures ANOVA showed there was no significant (P = 0.2) time × vitamin D treatment × calcium intake grouping interaction effect on the mean serum 25(OH)D concentration over the 15-wk intervention period. Serum 25(OH)D concentrations increased (P ≤ 0.005) and decreased (P ≤ 0.002) in vitamin D3 and placebo groups, respectively, and were of similar magnitudes in subjects with calcium intakes <700 mg/d (and even <550 mg/d) compared with >1000 mg/d. The response of serum PTH, 1,25(OH)2D, 24,25(OH)2D, the ratio of 24,25(OH)2D:25(OH)D, and free 25(OH)D significantly differed in vitamin D3 and placebo groups but not by calcium intake grouping. We found no evidence of a vitamin D sparing effect of high calcium intake, which has been referred to by some authors as "vitamin D economy." Thus, recent dietary vitamin D requirement estimates will cover the vitamin D needs of even those individuals who have inadequate calcium intakes. This trial was registered at clinicaltrials.gov as NCT01990872.
    American Journal of Clinical Nutrition 04/2014; 99(6). DOI:10.3945/ajcn.113.080358 · 6.92 Impact Factor
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    ABSTRACT: The content and bioaccessibility of carotenoids from different chili peppers were analysed and the effects of typical domestic processing were investigated. Peppers were analysed before and after cooking by conventional boiling (10min in 100°C water) and also following a freezing period of four months in a domestic freezer (-20°C). The content and bioaccessibility of the eight carotenoids quantified varied, depending on cultivar, species, colour and processing. Provitamin A carotenoids (β-carotene and β-cryptoxanthin) and capsanthin were present at highest concentrations in the samples before and after processing. In general, yellow and orange peppers were the best sources of lutein, zeaxanthin and neoxanthin. Xanthophyll carotenoids were more efficiently transferred to the micelles and, therefore, were also more bioavailable. Processing decreased the carotenoid content in certain samples; however, the micellar content was generally not lower for processed peppers; therefore the bioaccessibility of carotenoids from processed peppers is enhanced relative to unprocessed peppers.
    Food Chemistry 12/2013; 141(3):2606-13. DOI:10.1016/j.foodchem.2013.05.046 · 3.39 Impact Factor
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    ABSTRACT: Chilli peppers have been recognized as an excellent source of antioxidants as they are rich in bioactive phytochemicals such as carotenoids which are known to exert various beneficial effects in vivo. Absorption is an important factor in the determination of the potential biological effects of carotenoids. The bioaccessibility of a food constituent such as a carotenoid represents its potential to be absorbed in humans. There is very limited information in the literature regarding the content and bioaccessibility of carotenoids from dried peppers. Therefore, the objectives of the present study were: first, to determine the carotenoid content of 20 varieties of red, orange or yellow coloured sun-dried chilli peppers belonging to either of four Capsicum species (annuum, baccatum, chinense and chacoense); and second, to quantify the carotenoid micellarization (bioaccessibility) following an in vitro digestion procedure. Red peppers had a higher carotenoid content and bioaccessibility than either the orange peppers or yellow pepper. Xanthophylls showed greater bioaccessibility than carotenes. Our findings confirm that dried chilli peppers are a good source of carotenoids.
    Plant Foods for Human Nutrition 11/2013; DOI:10.1007/s11130-013-0397-2 · 2.42 Impact Factor
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    ABSTRACT: Carotenoid-rich foods are associated with antioxidant activity and the ability to alleviate chronic diseases. The present study investigated the effect of processing on the content and bioaccessibility of carotenoids from 13 cultivars of red chili pepper (Capsicum annuum). Carotenoids in chili peppers were analyzed before an in vitro digestion process. The portion of carotenoid transferred to the micelle fraction (bioaccessibility) was also quantified. β-Carotene, β-cryptoxanthin, capsanthin and antheraxanthin were the most abundant carotenoids. Zeaxanthin, violaxanthin, neoxanthin and lutein were detected at lower concentrations. In general, freezing and boiling reduced carotenoid contents. Capsanthin and zeaxanthin had the highest bioaccessibility at an average value from 36 to 40 %, followed by antheraxanthin (26 %). Bioaccessibility of β-cryptoxanthin, violaxanthin and β-carotene was lower, averaging 6.1, 4.8 and 4.0 %, respectively. Neoxanthin and lutein were not detected in micelles. Freezing increased the bioaccessibility of capsanthin, zeaxanthin, antheraxanthin, β-cryptoxanthin and violaxanthin; β-cryptoxanthin bioaccessibility increased and capsanthin and zeaxanthin bioaccessibility decreased following boiling. Differences in the contents and bioaccessibility of carotenoids in 13 C. annuum cultivars and between the processed methods were herein evidenced.
    European Journal of Nutrition 07/2013; 53(2). DOI:10.1007/s00394-013-0555-1 · 3.84 Impact Factor
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    ABSTRACT: Changes that may be expected in crocetin esters (crocins) upon digestion were examined in saffron aqueous extracts for the first time. Chemical characterization of total and individual crocins, and other bioactive compounds was achieved by UV-vis spectrophotometry, RP-HPLC-DAD and LC-ESI-MS. Antioxidant activity was evaluated using in vitro assays and the comet assay. The observed loss for both total and trans-crocins was higher in saffron (~50%) than in gardenia extracts (~30%) which were also examined for comparison. Loss was lower than that reported for hydrophobic carotenoids. Cis-isomers were less affected leading to the hypothesis that trans/cis isomerization may occur in parallel to degradation reactions. Monitoring changes in the extracts at oral, gastric or intestinal phases, separately, verified this view pointing out the critical effect of pH, temperature and duration of process but not of digestive enzymes. No isomerization and less degradation (<20% loss) was evidenced when pure trans-crocetin (di-β-D-gentiobiosyl) ester was subjected to gastric or intestinal conditions.
    Journal of Agricultural and Food Chemistry 05/2013; DOI:10.1021/jf400540y · 3.11 Impact Factor
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    Proceedings of The Nutrition Society 01/2012; 71(OCE2). DOI:10.1017/S0029665112001115 · 4.94 Impact Factor
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    ABSTRACT: Few studies have looked at the isomeric profile and micellarization of β-carotene (BC) isomers in green vegetables. Therefore, the aims of the present study were, first, to assess the isomeric profile of BC isomers in raw and cooked vegetables namely broccoli, kale, spinach and Savoy cabbage and, second, to examine the impact of boiling on the BC isomeric profile of the vegetables, their respective micelle fractions and on efficiency of micellarization. All vegetables were subjected to an in vitro digestion procedure. All-trans-, 9-cis- and 13-cis-BC were present in the four vegetables tested. BC isomerization occurred following the cooking of spinach and, to a lesser extent, Savoy cabbage. The isomeric profile of the micelle fractions from broccoli and spinach altered as a result of cooking, but not kale and Savoy cabbage. Our findings suggest that the food matrix may play a role in the effects of cooking on BC isomerization.
    Food Research International 05/2010; 43(4-43):1130-1135. DOI:10.1016/j.foodres.2010.02.012 · 3.05 Impact Factor
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    ABSTRACT: The unsaponifiable lipid fraction of plant-based foods is a potential source of bioactive components such as phytosterols, squalene, and tocopherols. The objective of the present study was to determine the levels of phytosterols, and squalene, as well as tocopherols (alpha and beta + gamma) in selected grains, seeds, and legumes. The method comprised acid hydrolysis and lipid extraction followed by alkaline saponification, prior to analysis by HPLC. In addition, the fatty acid profile of the foods was determined via total lipid extraction, fatty acid derivitisation and GC analysis. In general, beta-sitosterol was the most prevalent phytosterol, ranging in concentration from 24.9 mg/100 g in pumpkin seed to 191.4 mg/100 g in peas. Squalene identified in all foods examined in this study, was particularly abundant in pumpkin seed (89.0 mg/100 g). The sum of alpha- and beta+ gamma-tocopherols ranged from 0.1 mg/100 g in rye to 15.9 mg/100 g in pumpkin seeds. Total oil content ranged from 0.9% (w/w) in butter beans to 42.3% (w/w) in pumpkin seed and the type of fat, in all foods examined, was predominantly unsaturated. In conclusion, seeds, grains, and legumes are a rich natural source of phytosterols. Additionally, they contain noticeable amounts of squalene and tocopherols, and in general, their fatty acid profile is favorable.
    Plant Foods for Human Nutrition 10/2007; 62(3):85-91. DOI:10.1007/s11130-007-0046-8 · 2.42 Impact Factor
  • E Ryan · K Galvin · TP O'Connor · NM O'Brien
    Planta Medica 01/2007; 73(09). DOI:10.1055/s-2007-987410 · 2.34 Impact Factor
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    E Ryan · K Galvin · T P O'Connor · AR Maguire · N M O'Brien
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    ABSTRACT: Nuts contain bioactive constituents that elicit cardio-protective effects including phytosterols, tocopherols and squalene. The objective of the present study was to determine the total oil content, peroxide value, fatty acid composition and levels of tocopherols, squalene and phytosterols in oil extracted from freshly ground brazil, pecan, pine, pistachio and cashew nuts. The total oil content of the nuts ranged from 40.4 to 60.8% (w/w) while the peroxide values ranged from 0.14 to 0.22 mEq O2/kg oil. The most abundant monounsaturated fatty acid was oleic acid (C18:1), while linoleic acid (C18:2) was the most prevalent polyunsaturated fatty acid. The levels of total tocopherols ranged from 60.8 to 291.0 mg/g. Squalene ranged from 39.5 mg/g oil in the pine nut to 1377.8 mg/g oil in the brazil nut. beta-Sitosterol was the most prevalent phytosterol, ranging in concentration from 1325.4 to 4685.9 mg/g oil. In conclusion, the present data indicate that nuts are a good dietary source of unsaturated fatty acids, tocopherols, squalene and phytosterols.
    International Journal of Food Sciences and Nutrition 05/2006; 57(3-4):219-28. DOI:10.1080/09637480600768077 · 1.20 Impact Factor
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    ABSTRACT: In view of the reported potential anti-inflammatory activity of the New Zealand green lipped mussel (NZGLM), we aimed to compare the effect of low dose marine oil supplementation, from mussels and fish, in reducing blood markers of inflammation. Thirty apparently healthy males and females were recruited from the general public in Melbourne, Australia to participate in a double blind, randomised, parallel intervention study. Subjects were consuming approximately 73 mg of omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) daily in their background diet prior to the commencement of the intervention. Subjects were randomly assigned to consume either 2 mL/day of the NZGLM oil preparation (mixed with olive oil and dl-alpha-tocopherol) or fish oil preparation (also mixed with olive oil and dl-alpha-tocopherol) for six weeks. Two mL of the oils contained 241 mg and 181 mg of n-3 LCPUFA, respectively. Neutrophil phospholipid fatty acids, serum thromboxane B2 (TXB2), stimulated monocyte production of prostaglandin E2 (PGE2), interleukin-1 beta (IL-1 beta) and tumor necrosis factor alpha (TNFalpha) were measured. During the intervention, the total intakes of n-3 LCPUFA from the background diet and the supplements were 199 mg/d and 173 mg/day for the NZGLM and FO groups, respectively. Following six weeks of supplementation, both groups showed a small, but significant increase in neutrophil phospholipid proportion of eicosapentaenoic acid. The NZGLM group also showed a significant increase in docosahexaenoic acid levels. There were no significant changes with time or treatment for TXB2, PGE2, IL-1 beta or TNFalpha. This study showed that low dose supplementation with n-3 LCPUFA from two different marine oil preparations showed no difference in inflammatory markers in this group of healthy individuals. Further studies are warranted including dose response trials and studies in populations with inflammatory conditions.
    Asia Pacific Journal of Clinical Nutrition 02/2006; 15(3):418-24. · 1.36 Impact Factor
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    ABSTRACT: The objective of this study was to determine the effect of type of conserved forage and concentrate composition on the quality of beef held in overwrapped (aerobic) or modified atmosphere packaging under simulated retail display for 17 d. Friesian steers (n = 45) were assigned randomly to one of five dietary treatments: 1) extensively fermented grass silage plus silage concentrate (EFS); 2) restricted fermented grass silage plus silage concentrate (RFS); 3) starch-based concentrate plus wheat straw (SC); 4) nonstarch-based concentrate plus wheat straw (NSC); or 5) zero-grazed perennial ryegrass plus grass concentrate (RYE). Meat quality was determined by measuring color, lipid oxidation (TBARS), alpha-tocopherol concentrations, and fatty acid composition. In aerobically packaged beef, there was a display x diet interactive effect (P < 0.001) on Hunter a* values, with steaks from the EFS group having higher (P < 0.05) a* values than all other dietary groups from d 6 through d 17. Moreover, during the last 12 d of display, beef from the EFS group had the lowest (P < 0.01) proportion of metmyoglobin (display day x diet; P < 0.001). Under aerobic packaging, the SC and NSC groups produced steaks with higher (P < 0.05) TBARS values than RFS, EFS, and RYE groups, which did not differ from each other (display day x diet; P < 0.01). The SC and NSC groups had higher (P < 0.05) oxidation levels than RFS, EFS, and RYE groups, which did not differ from each other. Beef from the EFS group had (P < 0.05) higher concentrations of alpha-tocopherol than from the SC, NSC, and RYE groups. Beef from EFS-fed steers had a higher (P < 0.05) proportion of saturated fatty acids than the SC and NSC groups. It was concluded that the method of grass conservation influenced beef color, whereas concentrate composition did not. Color of aerobically packaged beef was improved by feeding animals silage that had undergone extensive fermentation. Conversely, oxidative stability was decreased by feeding animals starch- and nonstarch-based concentrate diets.
    Journal of Animal Science 08/2004; 82(8):2384-91. · 1.92 Impact Factor
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    ABSTRACT: Nuts are high in fat but have a fatty acid profile that may be beneficial in relation to risk of coronary heart disease. Nuts also contain other potentially cardioprotective constituents including phytosterols, tocopherols and squalene. In the present study, the total oil content, peroxide value, composition of fatty acids, tocopherols, phytosterols and squalene content were determined in the oil extracted from freshly ground walnuts, almonds, peanuts, hazelnuts and the macadamia nut. The total oil content of the nuts ranged from 37.9 to 59.2%, while the peroxide values ranged from 0.19 to 0.43 meq O2/kg oil. The main monounsaturated fatty acid was oleic acid (C18:1) with substantial levels of palmitoleic acid (C16:1) present in the macadamia nut. The main polyunsaturated fatty acids present were linoleic acid (C18:2) and linolenic acid (C18:3). alpha-Tocopherol was the most prevalent tocopherol except in walnuts. The levels of squalene detected ranged from 9.4 to 186.4 microg/g. beta-Sitosterol was the most abundant sterol, ranging in concentration from 991.2 to 2071.7 microg/g oil. Campesterol and stigmasterol were also present in significant concentrations. Our data indicate that all five nuts are a good source of monounsaturated fatty acid, tocopherols, squalene and phytosterols.
    International Journal of Food Sciences and Nutrition 06/2004; 55(3):171-8. DOI:10.1080/09637480410001725175 · 1.20 Impact Factor
  • Russell E.A · Lynch A · Galvin K · Lynch P.B · Kerry J.P
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    ABSTRACT: Poultry meat, particularly that of duck, has relatively high levels of unsaturated fatty acids and low levels of antioxidants. Ducks consume twice as much feed as broilers during growth, therefore, duck meat is more likely to be influenced by diet than chicken meat. The effects of dietary fat differing in unsaturation level (2.5% tallow or olive, sunflower or linseed oils) together with α-tocopheryl acetate ( α-TA) at either a control (20 mg α-TA/kg feed) or a supplemented level (400 mg α-TA/kg feed) on α-tocopherol content, fatty acid composition and lipid oxidation of duck muscle in 7 week old birds were investigated. Fat source influenced fatty acid composition of duck meat. Ducks fed tallow had a higher percentage saturated fats, while ducks fed olive oil had a higher percentage monounsaturated fats than other dietary groups. In the absence of supplemental α-TA, duck muscle stability to lipid oxidation was greatest for those receiving diets containing sunflower oil and lowest for those receiving tallow. α-Tocopherol content and oxidative stability of duck muscle were increased (p < 0.05) by α-TA supplementation irrespective of fat source. Interestingly oxidative changes were much more extensive in duck breast meat than corresponding thigh meat for all treatment groups. This finding is in contrast when compared with similar dietary trials for chicken and turkey. Therefore, oxidative stability of duck meat differs from that of other poultry meats.
    International Journal of Poultry Science 05/2003; DOI:10.3923/ijps.2003.324.334
  • Z Formanek · A Lynch · K Galvin · J Farkas · J P Kerry
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    ABSTRACT: Five batches of aerobically packaged minced beef from Friesian cattle were irradiated at 0, 1, 2, 3 or 4 kGy using a (60)Co irradiation source. The five batches were as follows: non-supplemented (C), dietary α-tocopheryl acetate supplemented (S), α-tocopheryl acetate supplemented with water soluble rosemary extract added after mincing (Rw), α-tocopheryl acetate supplemented with oil soluble rosemary extract added after mincing (Ro) and α-tocopheryl acetate supplemented with water and oil soluble rosemary extracts added after mincing (R). Incorporation of antioxidants resulted in better retention of colour. Irradiation at 4 kGy increased Hunter 'a' values up to day 4 with α-tocopheryl acetate supplementation and up to day 6 when rosemary extracts were added. Irradiation at 4 kGy increased Hunter 'b' values on days 4, 6 and 8 in the control samples. Antioxidants decreased metmyoglobin values on day 0 and day 2 for non-irradiated (0 kGy) samples and for the entire display period for irradiated samples. Antioxidants increased the oxymyoglobin values up to day 4 for the 1, 2 and 3 kGy beef samples and over the entire display period for the 4 kGy samples. TBARS values for each treatment group increased with increasing irradiation dose. α-Tocopheryl acetate supplemented samples had lower TBARS values than control samples at all irradiation doses. The levels of α-tocopherol in samples on day 0 decreased with increasing irradiation dose for the (C) and (S) samples. However, levels of α-tocopherol in samples on day 0 increased with increasing irradiation dose for Ro, Rw and R samples. All antioxidant treatments were effective at inhibiting lipid peroxidation even at the highest irradiation dose applied. Irradiation caused a significant reduction in the polyunsaturated fatty acid (PUFA) content, mainly in C18:2 after storage at 40°C under fluorescent light for 8 days.
    Meat Science 04/2003; 63(4):433-40. DOI:10.1016/S0309-1740(02)00063-3 · 2.23 Impact Factor
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    ABSTRACT: Continental Limousin and Charolais crossbred steers (n=66) were assigned to one of six diets: (1) high herbage allowance (18 kg grass dry matter), zero concentrate (HH0C), (2) high herbage allowance and 2.5 kg concentrate (HHLC), (3) high herbage allowance and 5 kg concentrate (HHHC), (4) low herbage allowance (6 kg grass DM) and 5 kg concentrate (LHHC), (5) medium herbage allowance (12 kg grass DM) and 2.5 kg concentrate (MHLC) or (6) concentrates ad-libitum+1 kg straw (CON). Colour was assessed in steaks (n=5) chosen at random from each dietary group and held in overwrapped and/or modified atmosphere packaging (MAP) (80 O(2):20 CO(2)) under simulated retail display conditions for 17 days. When the HH0C and the CON groups were compared, there was no significant difference in colour under overwrapped conditions, however under MAP, surface redness was significantly (P<0.01) higher (greatest Hunter "a" values) in the HH0C group. When the other four diets were compared to the HH0C and CON groups, there was no significant difference in colour under both forms of packaging. Lipid oxidation was highest for the dietary group CON compared to all other dietary groups examined. There was no significant difference in vitamin E levels between the six dietary groups, levels ranged from 1.7 to 2.5 μg/g meat.
    Meat Science 03/2003; 63(3):279-86. DOI:10.1016/S0309-1740(02)00082-7 · 2.23 Impact Factor
  • A Lynch · D J Buckley · K Galvin · A M Mullen · D J Troy · J P Kerry
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    ABSTRACT: Heifers (n=10) were randomly selected from the slaughter line of a local factory each month for a period of 21 months. Rib steak (sampled at the 10th rib) from the left side of each carcass was taken for analysis. The cattle breeds selected during this study were Friesian, Hereford and Charolais. The mean weight of the left side for all carcasses was 146.6 (S.E.M.= 1.0kg). Graded carcasses selected for sampling during this trial were classified using the EUROP scale and the specific heifer grades chosen were factory grades EO4L and EO4H. Initial Hunter 'a' values (on the day of arrival in the laboratory) of rib steak from heifers finished between November and March (overwintered) were significantly (P<0.001) higher than Hunter 'a' values from heifers finished between April and October (pastured). After storage at 4 °C under simulated retail display conditions for 6 days, the Hunter 'a' values for overwintered samples were also significantly (P<0.001) greater than those for pastured samples. Breed also had an effect on the colour of the meat. After storage for 6 days, Hunter 'a' values of rib steak from Charolais were significantly (P<0.05) higher than either Friesian or Hereford. Pastured heifers had significantly (P<0.05) higher levels of the monounsaturated fatty acid C16.1 in the total lipid fraction of rib steak (neutral and polar) than samples taken from overwintered heifers. Pastured heifers had significantly (P<0.01) higher levels of the polyunsaturated fatty acid (PUFA) C18.3 in the phospholipid fraction than those from overwintered cattle. However, Hereford had significantly (P<0.05) higher levels of C14.0, C16.1 and C18.0 in the phospholipid fraction than those found in Friesian and Charolais. The level of α-tocopherol in the muscle was not affected by either pasturing/overwintering or breed. However, Continental breeds had significantly (P<0.05) higher levels of α-tocopherol in adipose tissue than Friesian.
    Meat Science 07/2002; 61(3):227-32. DOI:10.1016/S0309-1740(01)00177-2 · 2.23 Impact Factor
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    ABSTRACT: The effects of three preslaughter diets on heifer beef quality were investigated. Heifers (n = 45) were divided into three groups and fed for ad libitum consumption either maize silage, grass silage, or a 50:50 mixture of maize silage and grass silage. Meat quality was determined by measuring color, lipid oxidation, alpha-tocopherol levels, and fatty acid composition. Beef from the maize silage group had poorest color stability (P < 0.05), whereas beef from the grass silage diet had best (P < 0.05) color stability. The visual panel least preferred the maize silage group after 2 or more days of display, and lipid oxidation was significantly (P < 0.001) higher in this group compared to the 50:50 maize:grass silage and grass silage groups. There was a significant (P < 0.001) difference in the alpha-tocopherol levels detected in the meat from the three dietary groups. Alpha-tocopherol levels increased in the order: maize silage < 50:50 maize:grass silage < grass silage, at levels of 2.08, 2.95, and 3.84 microg/g meat, respectively. Fatty acid analysis indicated 18:3 was significantly (P < 0.001) lower in the maize silage-fed group than in the maize:grass silage and grass silage groups. However, 18:3 was significantly (P < 0.001) higher in the grass silage group than in the other two groups. There were no significant differences in all other fatty acids among the three dietary groups. It was concluded that beef from grass silage-fed animals had better overall quality in terms of color, lipid oxidation, and alpha-tocopherol levels than beef from maize silage fed animals.
    Journal of Animal Science 06/2002; 80(6):1556-63. · 1.92 Impact Factor
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    ABSTRACT: The effect of dietary vitamin E supplementation on cholesterol oxidation in vacuum packaged, cooked, refrigerated and frozen beef steaks, was investigated. Steers (Friesian×Charolais×Black Hereford) were fed diets providing 20 or 3000 mg α-tocopheryl acetate/head/day for 135 days prior to slaughter. α-Tocopherol concentrations in M. psoas major (PM) and M. longissimus dorsi (LD) were significantly (p<0.05) increased by supplementation and were significantly (p<0.05) higher in PM than LD. Cholesterol oxidation (monitored by measuring 7-ketocholesterol formation) increased during refrigerated and frozen storage in some, but not all, groups, and tended to be higher in PM than LD. Dietary vitamin E did not affect 7-ketocholesterol formation in LD, but significantly (p<0.05) reduced concentrations in PM during refrigerated and frozen storage. Supplementation significantly (p<0.05) reduced TBARS in PM and LD, indicating that vitamin E improved oxidative stability in both muscles. The results show that dietary vitamin E supplementation inhibits cholesterol oxidation in vacuum packaged, cooked beef during refrigerated and frozen storage, but may be influenced by muscle type.
    Meat Science 05/2000; 55(1):7-11. DOI:10.1016/S0309-1740(99)00119-9 · 2.23 Impact Factor