Research Output
1 - 7 of 7
Publication
A consumer study of the effect of castration and slaughter age of lambs on the sensory quality of meat
2018-12, Gravador, Rufielyn S., Pace, Elaine, Mooney, Bernard R., Gkarane, Vasiliki, Fahey, Alan G., Brunton, Nigel P., Claffey, Noel A., Monahan, Frank J., et al.
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.
Publication
Effect of finishing diet and duration on the sensory quality and volatile profile of lamb meat
2019-01, Gkarane, Vasiliki, Brunton, Nigel P., Allen, Paul, Gravador, Rufielyn S., Fahey, Alan G., Murphy, P. (Patrick), Monahan, Frank J., et al.
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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Publication
Recovery of ergosterol and vitamin D2 from mushroom waste - Potential valorization by food and pharmaceutical industries
2020-05, Papoutsis, Konstantinos, Grasso, Simona, Menon, Ajay, Brunton, Nigel P., Lyng, James G., Jacquier, Jean Christophe, Bhuyan, Deep Jyoti
Background: A large amount of mushroom waste is generated during mushroom production (accounting for up to 20% of total production) and is mainly composed of mushrooms that do not meet the specifications set by retailers because of misshapen caps and/or stalks. Mushrooms are notable for their ergosterol (a precursor of vitamin D2) content which is converted to vitamin D2 after exposure to natural or artificial ultraviolet (UV) irradiation. Therefore, mushroom waste could be used as a source for the recovery of both ergosterol and vitamin D2 which could be valorized by both pharmaceutical and food industries. Scope and approach: The current review presents a comprehensive summary of research performed regarding the extraction, purification and determination of ergosterol and vitamin D2 (ergocalciferol) from mushroom matrices. Additionally, studies related to the impact of sample preparation and especially of drying methods on the retention of ergosterol and vitamin D2 are presented. Finally, the potential valorization of mushroom waste sterols by food and pharmaceutical industries is discussed. Key findings and conclusions: Ergosterol and vitamin D2 contents vary among different mushroom species. Sample drying is a crucial step that precedes sterol extraction and has a significant impact on the retention of ergosterol and vitamin D2. The extraction of sterols from mushrooms can be conducted by either conventional (e.g., Soxhlet extraction) or non-conventional methods (e.g., ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), deep eutectic solvents (DES) extraction, supercritical fluid extraction (SFE), and pressurized liquid extraction (PLE)) or their combination. The application of non-conventional methods such as UAE and MAE facilitate in shorter extraction times than the conventional methods. The valorization of mushroom extracts enriched in ergosterol and vitamin D2 by both pharmaceutical and food industries requires further work.
Publication
Profiling of the Molecular Weight and Structural Isomer Abundance of Macroalgae-Derived Phlorotannins
2015-01-16, Heffernan, Natalie, Brunton, Nigel P., FitzGerald, Richard J., Smyth, Thomas
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.
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High-Pressure Processing for the Production of Added-Value Claw Meat from Edible Crab (Cancer pagurus)
2021-04-27, Lian, Federico, De Conto, Enrico, Del Grippo, Vincenzo, Harrison, Sabine M., Fagan, John, Lyng, James G., Brunton, Nigel P.
High-pressure processing (HPP) in a large-scale industrial unit was explored as a means for producing added-value claw meat products from edible crab (Cancer pagurus). Quality attributes were comparatively evaluated on the meat extracted from pressurized (300 MPa/2 min, 300 MPa/4 min, 500 MPa/2 min) or cooked (92◦ C/15 min) chelipeds (i.e., the limb bearing the claw), before and after a thermal in-pack pasteurization (F9010 = 10). Satisfactory meat detachment from the shell was achieved due to HPP-induced cold protein denaturation. Compared to cooked or cooked– pasteurized counterparts, pressurized claws showed significantly higher yield (p < 0.05), which was possibly related to higher intra-myofibrillar water as evidenced by relaxometry data, together with lower volatile nitrogen levels. The polyunsaturated fatty acids content was unaffected, whereas the inactivation of total viable psychrotrophic and mesophilic bacteria increased with treatment pressure and time (1.1–1.9 log10 CFU g−1 ). Notably, pressurization at 300 MPa for 4 min resulted in meat with no discolorations and, after pasteurization, with high color similarity (∆E* = 1.2–1.9) to conventionally thermally processed samples. Following further investigations into eating quality and microbiological stability, these HPP conditions could be exploited for producing uncooked ready-to-heat or pasteurized ready-to-eat claw meat products from edible crab.
Publication
Volatile Profile of Grilled Lamb as Affected by Castration and Age at Slaughter in Two Breeds
2018-09-25, Gkarane, Vasiliki, Brunton, Nigel P., Harrison, Sabine M., Gravador, Rufielyn S., Fahey, Alan G., Monahan, Frank J., et al.
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.
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Increasing the Yield of Irish Brown Crab (Cancer pagurus) during Processing without Adversely Affecting Shelf-Life
2018-06-27, McDermott, Aoife, Whyte, Paul, Brunton, Nigel P., Lyng, James G., Bolton, Declan J.
During the processing of Irish Brown Crab (Cancer pagurus), protein and moisture are released and losses up to 10% (by weight) are common. The objective of this study was to investigate the use of clean label ingredients to reduce this loss, without adversely affecting shelf-life or promoting the growth of spoilage bacteria. Following preliminary studies, 5% (w/v) sodium caseinate (SC) and (5%, w/v) potato starch (PS), with and without (0.5%, w/v) ascorbic acid (AA) were selected. Ninety crabs (30 per treatment) were soaked and boiled in water (control 1), AA (control 2), SC, PS, SC plus AA, or PS plus AA and analyzed for cook loss as well as pH, aw, water holding capacity (WHC), and microbial shelf-life (total viable count (TVC), total Enterobacteriaceae count (TEC), and spoilage bacteria) during 28 days storage at 4 â—¦ C. On average, 11.1% of the control 1 weight was lost during processing. This was reduced to 8.0% when treated with AA (control 2) and to 3.5%, 4.7%, 5.8%, and 2.3% with SC, PS, SC plus AA, and PS plus AA, respectively. None of these treatments negatively impacted on shelf-life and similar growth curves were observed for TVC, TEC, Pseudomonas spp., Clostridium spp., lactic acid bacteria (LAB), and hydrogen disulphide producing bacteria, regardless of treatment. It was therefore concluded that, subject to sensory evaluation and validation under commercial conditions, these natural ingredients could be used to substantially increase the yield and hence commercial value of crab meat, without adversely affecting shelf-life.