Now showing 1 - 4 of 4
  • Publication
    A consumer study of the effect of castration and slaughter age of lambs on the sensory quality of meat
    Meat from ram lambs is often considered inferior to meat from castrated lambs, especially in older or heavier animals. This study aimed to determine if differences exist in the sensory quality and acceptability of meat from rams and castrates, slaughtered at mean ages of 196 or 385 days. Rams had higher average daily gain, feed conversion efficiency, total weight gain and lower carcass fatness than castrates. A triangle test (n = 81 consumers) showed a difference (P < 0.05) in the sensory quality of meat from rams vs castrates. A 9-point hedonic test involving 100 consumers showed that, although meat from both rams and castrates was ‘liked’, meat from castrates scored higher (P < 0.05) in Overall Liking, Flavour Liking and Tenderness Liking. Meat from castrates was also rated lower (P < 0.05) in Unpleasant Taste/Off-Flavour Intensity. Flavour Intensity and Unpleasant Taste/Off-Flavour Intensity increased (P < 0.05) with age at slaughter. This consumer study revealed that while meat from castrates was higher in Overall Liking, Flavour Liking and Tenderness Liking and lower in Unpleasant Taste/Off-Flavour Intensity than meat from rams, both meats were ‘liked’ by consumers.
      243Scopus© Citations 6
  • Publication
    Effect of finishing diet and duration on the sensory quality and volatile profile of lamb meat
    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.
      374Scopus© Citations 27
  • Publication
    Profiling of the Molecular Weight and Structural Isomer Abundance of Macroalgae-Derived Phlorotannins
    Phlorotannins are a group of complex polymers of phloroglucinol (1,3,5-trihydroxybenzene) unique to macroalgae. These phenolic compounds are integral structural components of the cell wall in brown algae, but also play many secondary ecological roles such as protection from UV radiation and defense against grazing. This study employed Ultra Performance Liquid Chromatography (UPLC) with tandem mass spectrometry to investigate isomeric complexity and observed differences in phlorotannins derived from macroalgae harvested off the Irish coast (Fucus serratus, Fucus vesiculosus, Himanthalia elongata and Cystoseira nodicaulis). Antioxidant activity and total phenolic content assays were used as an index for producing phlorotannin fractions, enriched using molecular weight cut-off dialysis with subsequent flash chromatography to profile phlorotannin isomers in these macroalgae. These fractions were profiled using UPLC-MS with multiple reaction monitoring (MRM) and the level of isomerization for specific molecular weight phlorotannins between 3 and 16 monomers were determined. The majority of the low molecular weight (LMW) phlorotannins were found to have a molecular weight range equivalent to 4â 12 monomers of phloroglucinol. The level of isomerization within the individual macroalgal species differed, resulting in substantially different numbers of phlorotannin isomers for particular molecular weights. F. vesiculosus had the highest number of isomers of 61 at one specific molecular mass, corresponding to 12 phloroglucinol units (PGUs). These results highlight the complex nature of these extracts and emphasize the challenges involved in structural elucidation of these compounds.
      240Scopus© Citations 111
  • Publication
    Volatile Profile of Grilled Lamb as Affected by Castration and Age at Slaughter in Two Breeds
    The aim of this study was to assess the effect of castration and slaughter age on the volatile profile of cooked meat from Scottish Blackface (SB) and Texel × Scottish Blackface (T × SB) lambs. M. longissimus thoracis et lumborum was sampled at slaughter and subjected to volatile analysis by SPME-GC-MS. Rams had higher relative proportions, expressed as relative abundance (RA), in lipid oxidation products while castrates had higher RA in pyrazines and benzenoid compounds. There was no consistent age effect on the RA of volatiles, although rams in November and January had a different volatile profile to castrates. There were higher proportions of free branched-chain fatty acids in muscle from SB compared to T × SB lambs. Overall, the results showed that production factors affected the volatile profile of cooked lamb meat which may explain differences in lamb flavor. Practical Application: Lamb meat has a characteristic flavor which, according to the evidence to date, may be influenced by farm production factors like gender or slaughter age. Our results showed variations in the proportions of some flavor compounds in cooked lamb between rams and castrated lambs while an increase in slaughter age did not have a consistent effect on proportions of compounds.
      437Scopus© Citations 27