The authenticity of meat is now an important consideration in the multi-step food chain from production of animals on farm to consumer consumption of the final meat product. A range of techniques, ...involving analysis of elemental and molecular constituents of meat, fingerprint profiling and multivariate statistical analysis exists and these techniques are evolving in the quest to provide robust methods of establishing the dietary background of animals and the geographical origin of the meat derived from them. The potential application to meat authentication of techniques such as stable isotope ratio analysis applied to different animal tissues, measurement in meat of compounds directly derived from the diet of animals, such as fatty acids and fat soluble vitamins, and spectroscopy is explored. Challenges pertaining to the interpretation of data, as they relate to assignment of dietary background or geographical origin, are discussed.
•A range of measurements (elemental, molecular, fingerprint) exists to assign provenance to meat•Stable isotopes are indicators of dietary background and geographical origin•Seasonal variation in diet and animal movement provide challenges for authentication•Incremental tissues offer potential for a forensic approach to meat authentication
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Visible-near infrared spectroscopy (Vis-NIRS) has been suggested to have potential for authentication of food products. The aim of the present preliminary study was to assess if this technology can ...be used to authenticate the ageing time (3, 7, 14 and 21 days post mortem) of beef steaks from three different muscles (M. Longissimus thoracis, M. Gluteus medius and M. Semitendinosus). Various mathematical pre-treatments were applied to the spectra to correct scattering and overlapping effects, and then partial least squares-discrimination analysis (PLS-DA) procedures applied. The best models were specific for each muscle, and the ability of prediction of ageing time was validated using full (leave-one-out) cross-validation, whereas authentication performance was evaluated using the parameters of sensitivity, specificity and overall correct classification. The results indicate that overall correct classification ranging from 94.2 to 100% was achieved, depending on the muscle. In conclusion, Vis-NIRS technology seems a valid tool for the authentication of ageing time of beef steaks.
•Vis-NIRS was able to predict ageing time with an overall correct classification ranging from 94.2 to 100%.•The ability of Vis-NIRS to authenticate ageing time was equally good for the three muscles studied.•With the relatively small set used, Vis-NIRS shows good potential as an authentication tool for aged steaks.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This paper focuses on dietary approaches to control intramuscular fat deposition to increase beneficial omega-3 polyunsaturated fatty acids (PUFA) and conjugated linoleic acid content and reduce ...saturated fatty acids in beef. Beef lipid trans-fatty acids are considered, along with relationships between lipids in beef and colour shelf-life and sensory attributes. Ruminal lipolysis and biohydrogenation limit the ability to improve beef lipids. Feeding omega-3 rich forage increases linolenic acid and long-chain PUFA in beef lipids, an effect increased by ruminally-protecting lipids, but consequently may alter flavour characteristics and shelf-life. Antioxidants, particularly α-tocopherol, stabilise high concentrations of muscle PUFA. Currently, the concentration of long-chain omega-3 PUFA in beef from cattle fed non-ruminally-protected lipids falls below the limit considered by some authorities to be labelled a source of omega-3 PUFA. The mechanisms regulating fatty acid isomer distribution in bovine tissues remain unclear. Further enhancement of beef lipids requires greater understanding of ruminal biohydrogenation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Scope
High‐fat diet (HFD)‐induced obesity impairs macrophage‐to‐feces reverse cholesterol transport (RCT). It is hypothesized that dietary supplementation with the polyunsaturated fatty acids ...conjugated linoleic acid (CLA) or alpha linolenic acid (ALA) would prevent HFD‐impaired RCT by modulating hepatic protein pathways.
Methods and results
ApoE3L.CETP mice are fed a HFD supplemented ± CLA or ALA for 12 weeks and in vivo macrophage‐to‐feces RCT is determined. Hepatic cholesterol transporters and the hepatic proteome are assessed by immunoblotting and mass spectrometry, respectively. Mice fed HFD alone, but not ALA‐HFD or CLA‐HFD, exhibit increased systemic cholesterol levels, increased 3H‐cholesterol levels in plasma and liver but not feces during RCT, and reduced hepatic ABCG5/8 expression relative to LFD. ALA‐HFD significantly reduces liver weight, hepatic cholesterol levels, and expression of the cholesterol synthesis enzyme farnesyl pyrophosphate synthase relative to HFD. ALA further increases the expression of acetyl‐coA oxidase‐associated proteins and suppress PPARα‐induced proteins relative to HFD. CLA does not significantly attenuate hepatic lipid levels but is associated with reduced hepatic expression of fatty acid binding protein (FABP)‐1/FABP4 levels relative to HFD, and reduced inflammatory pathway activation relative to ALA‐HFD.
Conclusion
ALA and CLA exert distinct mechanistic advantages on cholesterol homeostasis and RCT in obesity.
Saturated‐fat‐induced obesity increases cholesterol levels due to reduced elimination. Here, it is demonstrated that supplementation of a saturated‐fat diet with polyunsaturated fats (ALA or CLA) reduces cholesterol levels, but does so by different pathways. ALA activates proteins involved in burning of fat (Acox1) and reduces proteins involved in cholesterol synthesis (FDPS), which are associated with reduced liver fat accumulation. CLA reduces cholesterol synthesis enzyme (HMG‐CoA reductase) and reduces inflammation, but does not affect liver fat levels.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•IMF decreased with feeding grazed grass prior to concentrate finishing.•Muscle fatty acids and volatiles reflected grazed grass/grass silage feeding.•The grazed grass effect on muscle composition ...persisted after concentrate finishing.•Sensory differences were correlated with IMF and some fatty acids.
Fatty acids, volatile compounds and sensory attributes of beef from bulls fed concentrates to slaughter (C), grass silage for 120days (GS) followed by C (GSC), or GS followed by 100days at pasture and then C (GSPC), and slaughtered at 3 target carcass weights, were determined. Total intramuscular fat (IMF) was lower for GSPC than for GSC and C. C18:3n–3 concentration and polyunsaturated fatty acid (PUFA) to saturated fatty acid (SFA) ratio were higher and C18:2n–6 and monounsaturated fatty acid concentrations and n–6:n–3 PUFA ratio lower for GSPC than C. C16:0, C18:0 and C18:1c9 increased with carcass weight when expressed quantitatively, but not when expressed proportionately. Hexanal concentration was higher and 2-methyl-1-butanol and toluene lower for C and GSC than for GSPC. Overall liking was negatively correlated with C20:5n–3 and PUFA/SFA ratio, but differences in sensory attributes (tenderness, flavour liking, overall liking) were most strongly correlated with IMF.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Thirty-six steers were randomly assigned to one of three dietary treatments fed ad libitum grass silage and concentrate supplements containing either barley/soybean meal (CON), 80% DM corn (CDGS)- or ...80% DM wheat (WDGS)-dried distillers' grains with solubles for 124 days pre-slaughter. Chemical and fatty acid composition, shelf-life, and eating quality of longissimus thoracis muscle were determined. Dietary CDGS and WDGS increased the proportion of conjugated linoleic acids (P < 0.05) and tended to increase C18:3n-3 (P = 0.075) and total polyunsaturated fatty acids (P = 0.060) relative to the CON. Feeding diets containing distillers' grains reduced the lipid and colour stability of fresh beef patties stored in modified atmosphere packs (MAP), with CDGS exhibiting an intermediate effect between CON and WDGS. Diet did not negatively influence the texture profile parameters and eating quality attributes of beef stored in MAP. The inclusion of CDGS or WDGS in supplementary concentrates may improve the fatty acid profile but decreased the shelf-life of beef.
•Corn or wheat DGS was included in concentrate supplement fed to steers offered grass silage.•Feeding DGS may improve the fatty acid profile of beef.•DGS diets had no impact on the antioxidant capacity of beef.•DGS diets increased the lipid oxidation and reduced colour stability of fresh beef patties.•Texture profile and eating quality of beef were not affected by feeding DGS.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
To apply a dietary modelling approach to investigate the impact of substituting beef intakes with three types of alternative fatty acid (FA) composition of beef on population dietary fat intakes.
...Cross-sectional, national food consumption survey - the National Adult Nutrition Survey (NANS). The fat content of the beef-containing food codes (n 52) and recipes (n 99) were updated with FA composition data from beef from animals receiving one of three ruminant dietary interventions: grass-fed (GRASS), grass finished on grass silage and concentrates (GSC) or concentrate-fed (CONC). Mean daily fat intakes, adherence to dietary guidelines and the impact of altering beef FA composition on dietary fat sources were characterised.
Ireland.
Beef consumers (n 1044) aged 18-90 years.
Grass-based feeding practices improved dietary intakes of a number of individual FA, wherein myristic acid (C14 : 0) and palmitic acid (C16 : 0) were decreased, with an increase in conjugated linoleic acid (C18 : 2c9,t11) and trans-vaccenic acid (C18 : 1t11; P < 0·05). Improved adherence with dietary recommendations for total fat (98·5 %), SFA (57·4 %) and PUFA (98·8 %) was observed in the grass-fed beef scenario (P < 0·001). Trans-fat intakes were increased significantly in the grass-fed beef scenario (P < 0·001).
To the best of our knowledge, the present study is the first to characterise the impact of grass-fed beef consumption at population level. The study suggests that habitual consumption of grass-fed beef may have potential as a public health strategy to improve dietary fat quality.
Animal production factors can affect the sensory quality of lamb meat. The study investigated the effect of diet composition and duration of consumption on the proximate analysis, volatile profile ...and sensory quality of lamb meat. Ninety-nine male Texel × Scottish Blackface lambs were raised at pasture for 10 months before being assigned in groups of 11 to one of the following treatments: 100% Silage (S) for 36 (S36), 54 (S54) or 72 (S72) days; 50% Silage - 50% Concentrate (SC) for 36 (SC36), 54 (SC54) or 72 (SC72) days; 100% Concentrate (C) for 36 (C36) or 54 (C54) or 72 (C72) days. A trained sensory panel found Intensity of Lamb Aroma, Dry Aftertaste and Astringent Aftertaste to be higher in meat from lambs on the concentrate diet. Discriminant analysis showed that the volatile profile enabled discrimination of lamb based on dietary treatment but the volatile differences were insufficient to impact highly on sensory quality. Muscle from animals in the S54 group had higher Manure/Faecal Aroma and Woolly Aroma than the SC54 and C54 groups, possibly related to higher levels of indole and skatole. Further research is required to establish if these small differences would influence consumer acceptability.
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•The volatile profile of lamb meat differed between silage and concentrate-fed lambs.•Differences in the sensory attributes of lamb meat due to differing diets were minor.•Finishing diet duration influenced the sensory and volatile profile of lamb meat.•Discriminant analysis permitted separation of lamb meat based on the diet consumed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study investigated the quality composition, oxidative stability and sensory attributes of beef (longissimus thoracis, LT) from steers offered grass silage and a concentrate supplement in which ...barley was replaced by 40% and 80% (as-fed basis) of dried citrus pulp (DCP). Dietary treatment did not influence the antioxidant status (α-tocopherol and total phenolic contents) and activities of LT (radical scavenging activity, ferric reducing antioxidant power and iron chelating activity). Feeding DCP significantly increased the proportion of conjugated linoleic acids and polyunsaturated fatty acids in beef. Lipid and colour stability of fresh beef patties stored in modified atmosphere packs (MAP) were unaffected by dietary treatment but feeding 40% DCP reduced (P < .05) lipid oxidation in aerobically-stored cooked beef patties. Beef patties stored in MAP for up to 7 days were assessed by sensory panellists to be juicier for those fed 40% DCP compared to 0% and 80% DCP. Results indicated that substitution of barley with DCP improved the fatty acid profiles of beef without negatively influencing the eating quality of beef.
•Inclusion of dried citrus pulp (DCP) increased the dietary phenolic content.•Feeding DCP had no significant effect on the antioxidant capacity of beef.•DCP increased the proportion of CLA and PUFA in beef.•DCP did not affect the oxidative stability of fresh beef patties stored in MAP.•Dietary DCP had no negative influence on the eating quality of beef patties.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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