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Eighty-four crossbred wether and ewe lambs were allocated to four finishing diets. The diets were: Lucerne pasture (n = 24), Annual ryegrass with sub clover pasture (n = 18), Standard commercial feedlot pellets (n = 24) and Annual ryegrass based pasture and commercial feedlot pellets (500 g/day/head) (n = 18). After 8 weeks of feeding the lambs were slaughtered and the m. longissimus (LL) and m. semimembranosus (SM) were vacuum packaged and held chilled for 5 (fresh) or 60 (long aged) days, after which samples of each were displayed for 4 days under simulated retail conditions. Irrespective of muscle type the long aged samples exhibited a rapid reduction in redness (a*-values) and R630/580 nm ratio values such that consumer acceptable thresholds for both traits were quickly exceeded providing limited shelf life. Long ageing also lead to high TBARS levels measured as MDA mg/kg muscle suggestive of a product likely to exhibit rancidity and off flavours from lipid oxidation. [ABSTRACT FROM AUTHOR]

Abstract: Bovine milk is considered to be a good dietary source of vitamins A, E and β-carotene. This paper describes a robust method for the simultaneous determination of these compounds using high performance liquid chromatography–ion trap mass spectrometry (HPLC–MS n ) as the determinative step. The compounds were separated with a 5μm Polaris 2.1×150mm C18-A column and an aqueous-methanol mobile phase and the levels determined using the MS2 fragments (vitamin A, m/z 213 and m/z 199, vitamin E m/z 165 and β-carotene m/z 413). The HPLC–MS n was operated in the positive ion APCI mode. The method was validated using repeatability studies, duplicate analyses, recovery experiments, proficiency study data and comparison with previously validated high performance liquid chromatographic ultraviolet/visible (HPLC–UV/Vis) and fluorescence (HPLC–Fl) procedures used in our laboratory. Expanded measurement uncertainties were similar for HPLC–MS n , HPLC–UV/Vis and HPLC–Fl, e.g. vitamin A 45μg/100ml, HPLC–MS n ±8%, HPLC–UV ±9%; vitamin E 150μg/100ml, HPLC–MS n ±11%, HPLC–Fl ±9%; β-carotene 12μg/100ml, HPLC–MS n ±18%, HPLC–Vis ±21%. [Copyright &y& Elsevier]

Abstract: A renewed international interest in vitamin D status has revealed significant deficiencies in several populations, including Australia. Vitamin D exists in two forms, cholcalciferol (D3) and ergocalciferol (D2). The main source of vitamin D3 is from exposure of 7-dehydrocholesterol present in the skin to UV irradiation. However, there is an absolute requirement for vitamin D through proper dietary intake if humans live in the absence of sunlight or exclusively indoors. Bovine milk is considered to be a good dietary source of vitamin D3, even though the levels are quite low. This paper describes robust methods using liquid chromatography–linear ion trap mass spectrometry (LC–MSn) and liquid chromatography–tandem mass spectrometry (LC–MS/MS) to measure the levels of vitamin D3 in fresh bovine milk (0.05μg/100ml), commercial (natural and fortified) milk samples (0.01–2μg/100ml) and a dairy based infant formula (8μg/100g), without the need for extensive clean-up procedures. The limits of quantification (LOQ) are 0.01μg/100ml and 0.02μg/100ml for LC–MSn and LC–MS/MS, respectively. Recoveries of vitamin D3 added to the samples prior to saponification were satisfactory (range 60–90%). 25-Hydroxyvitamin D3 was not present in any of the samples analysed (LOQ=0.01μg/100ml, recovery range 30–40%). [ABSTRACT FROM AUTHOR]

Highlights: [•] Fifty polar lipids were identified by UHPLC-MS n in bovine milk from an animal feeding trial. [•] Ten compounds have not been previously identified in bovine milk. [•] 18:1 and 16:0 were the main fatty acids present in the polar lipids (apart from sphingomyelin). [•] Saturated fatty acids were located in sn-1, and PUFAs in the sn-2 position of the glycerol backbone. [•] Cow diets influenced the relative amounts of 8 polar lipids in the milk. [ABSTRACT FROM AUTHOR]

The effect of feeding flaxseed or algae supplements to lambs on muscle antioxidant potential (vitamin E), major fatty acid groups, lipid oxidation and retail colour was investigated. Lambs (n = 120) were randomly allocated to one of 4 dietary treatments according to liveweight and fed the following diets for eight weeks: Annual ryegrass hay [60%] + subterranean clover hay [40%] pellets = Basal diet; Basal diet with flaxseed (10.7%) = Flax; Basal diet with algae (1.8%) = Algae; Basal diet with flaxseed (10.7%) and algae (1.8%) = FlaxAlgae. Flaxseed or algae supplementation significantly affected major fatty acid groups in muscle. The addition of algae (average of Algae and FlaxAlgae) resulted in lower vitamin E concentration in muscle ( P < 0.003; 1.0 vs 1.3 mg/kg of muscle) compared with lambs fed a diet without algae (average of Basal and Flax). Increasing muscle EPA + DHA by algae supplementation significantly increased lipid oxidation, but retail display colour of fresh meat was not affected. [ABSTRACT FROM AUTHOR]

The aim of this experiment was to use metabolomic techniques to investigate the energy metabolism in lamb M. longissimus thoracis et lumborum subjected to very fast chilling (VFC) post-mortem . The tissue was prepared by 2 different operators and subjected to very fast chilling (less than 0 °C within 1.5 h of slaughter) or typical chilling regimes (Control; 0 °C within 22 h of slaughter). Non-targeted metabolomic analysis ( 1 H NMR) and targeted analysis ( 31 P NMR, HPLC-PDA and HPLC–MS/MS) were used to examine the change in muscle metabolites post-mortem . One VFC treatment, which resulted in a colder core temperature and more tender meat, had higher levels of glycolytic intermediate metabolites pre-rigor as well as more of the end-products of adenosine and nicotine nucleotide metabolism pre-rigor , relative to conventionally chilled treatments. In conclusion, VFC to less than 0 °C within 1.5 h of slaughter causes considerable changes in metabolism and rigor onset, which are associated with tender meat. [ABSTRACT FROM AUTHOR]

We investigated the association of muscle iron concentration, in addition to ultimate pH (pHU), on dark meat formation in sheep of different breeds fed forage-based diets. At 1 h simulated display, redness of meat (a*-value) increased (P <.0001) by about 3 units as the iron concentration increased from 10 to 22 mg/kg of meat, whereas the a*-value decreased by 2 units as pHU increased from 5.5 to 6.2 in fresh meat (P <.0001). After 90 days storage the corresponding responses were about 2 units increase for iron concentration and about 1 unit decrease for pHU, respectively. The results clearly show that increased muscle iron concentration was strongly associated with reduced dark cutting in fresh and stored meat evaluated at 1 h simulated display. We conclude that it may be desirable to measure iron concentration, along with pHU, for evaluation of the potential for carcasses to produce dark cutting meat, and for the meat to turn brown during display. • The association of muscle iron concentration and ultimate pH on redness of sheep meat at retail display was investigated • Increased muscle iron concentration was strongly associated with increased redness at 1 h retail display • The muscle iron effect on redness occurred both in fresh and in stored (aged) meat • The effect of muscle iron concentration was additive to the accepted effect of ultimate pH at 1 h retail display • There is a necessity to measure both iron concentration and ultimate pH when evaluating carcasses for dark cutting meat [ABSTRACT FROM AUTHOR]

Temperature-time combinations (TTC) effects on beef fatty acid (FA) composition, moisture content and oxidative traits were investigated. TTC were designed so temperatures were constant over each time period, and there was at most one variation in temperature within a sample's combined (total) time period. Therefore, three temperatures (~ 3, 5 and 7 °C) and five time periods (6, 8, 10 and 12 d) resulted in 72 different TTC, which were compared to control samples held for 14 d at ~ 1 °C. It was found that moisture losses increased as TTC temperature and time periods increased. There were negligible effects of TTC on FA composition. Sample TBARS and vitamin E content did not respond to TTC. A positive relationship between beef vitamin E and long chain polyunsaturated FA contents was observed. We concluded that TTC could be applied to accelerate the rate of ageing for beef and achieve comparable yield, oxidative and FA characteristics compared to conventional ageing approaches. [ABSTRACT FROM AUTHOR]