Two different techniques for obtaining extracts representing the most relevant aroma chemicals fr... more Two different techniques for obtaining extracts representing the most relevant aroma chemicals from grilled lamb have been developed and applied to the elucidation of the gas chromatographic-olfactometric (GC-O) profiles of grilled lamb from fresh or frozen samples. The first one attempted to collect the aroma released during grilling; the second one, the aroma released during eating. The GC-O work was complemented with a thorough isolation and identification study comprising liquid chromatography and dual gas chromatography with simultaneous MS and olfactometric (GC-GC-O-MS) detection.
This paper uses quality theory to identify opportunities for the meat sector that are consistent ... more This paper uses quality theory to identify opportunities for the meat sector that are consistent with trends in meat consumption. Meat consumption has increased and is likely to continue into the future. Growth is largely driven by white meats, with poultry in particular of increasing importance globally. The influence of factors such as income and price is likely decline over time so that other factors, such as quality, will become more important. Quality is complex and consumers' quality expectations may not align with experienced quality due to misconception of certain intrinsic cues. Establishing relevant and effective cues, based on extrinsic and credence attributes, could offer advantage on the marketplace. The use of extrinsic cues can help convey quality characteristics for eating quality, but also for more abstract attributes that reflect individual consumer concerns e.g. health/nutrition, and collective concerns, e.g. sustainability. However, attributes are not of equa...
To identify the most important aroma compounds in 20d-aged meat from castrated heavy Corriedale l... more To identify the most important aroma compounds in 20d-aged meat from castrated heavy Corriedale lambs fed one of four diets, grilled loin samples were subjected to a dynamic headspace-solid phase extraction (DHS-SPE) and gas chromatography-olfactometry (GC-O). Most of the important odorants were aldehydes and ketones. To evaluate the effect of finishing diet on carbonyl compounds, a derivatization of the headspace carbonyls using o-[(2,3,4,5,6-pentafluorophenyl)methyl]hydroxylamine hydrochloride (PFBHA) and analysis by GC-MS was conducted. Diet did not affect aliphatic saturated aldehydes. The meat from lambs finished on pastures, without a concentrate supplement, had very low concentrations of lipid-derived unsaturated aldehydes and ketones and Strecker aldehydes, possibly because of the protective effect of antioxidants that occur in the diet naturally. Lamb flavour was related to the concentration of heptan-2-one and oct-1-en-3-one, but rancid or undesirable flavours were not related to the abundance of carbonyl compounds.
ABSTRACT The effects of different freezing methods (nitrogen freezing tunnel, air blast freezer a... more ABSTRACT The effects of different freezing methods (nitrogen freezing tunnel, air blast freezer and home freezer) and frozen storage duration (1 month and 10 months) have been studied by sensory analyses and chemical analyses of odor-active compounds. The sensory analyses showed that fresh meat was significantly (p < 0.05) juicier than frozen meat. Meat frozen in the air blast freezer (ABF) and stored during 10 months had the highest lamb flavor intensity, significantly different from meat frozen in a home freezer (stored for 1 and 10 months) or in a nitrogen tunnel and stored for 1 month. The fresh sample was characterized by lower levels of Strecker aldehydes, 2-phenoxyethanol, cresols and to a lesser extent 2-methylbenzaldehyde, and higher levels of furaneol, which was not even detected in frozen samples. These compounds, together with the relative levels of octanoic acid and ethyl hexanoate, could be used as markers to detect whether lamb meat has been frozen. In chemical terms, the ABF samples were the most similar to fresh meat. Remarkably, in most cases the relative chemical aroma composition had no significant differences as a result of freezing. This helps explain the high sensory similarity observed. Only pyrazine levels changed significantly with frozen storage duration. No oxidation aromas or rancidity have been detected in fresh or frozen lamb.
Introduction - Winery by-products, which may constitute undesirable waste, can be used as feeding... more Introduction - Winery by-products, which may constitute undesirable waste, can be used as feeding supplements in ruminants, but they could modify product quality. Aim - To investigate the effect of wine by-products added to lactating ewes feeding on the ewe’s welfare, milk quality and their suckling lamb performance, carcass and meat quality. Material and methods - A total of 42 Chamarita breed ewes were allocated in one of three experimental diets: a control, based in concentrates without added by-product, and diets supplemented with either 10% grape pomace or 5% grape seed on a dry matter basis, during middle gestation and lactation. Ewe’s physiological welfare indicators and milk quality were assessed, and daily gain, carcass and meat quality (pH, cooking and thawing losses, texture and colour) in their suckling lambs were analysed. Results and discussion - Compared to the control group, cortisol levels was higher in the ewes fed pomace; whereas creatine kinase and non-esterified...
20 young males from Gasconne breed originated from two different production systems (extensive an... more 20 young males from Gasconne breed originated from two different production systems (extensive and semi-intensive) were fattened until 510 kg (slaughter live weight). After 24 hours Longissimus dorsi was obtained. For each animal one 1,5 cm steak was frozen for posterior fatty acids analysis (Bligh & Dyer) and three 2 cm steaks were aged during 1, 7 and 21 days at 4oC and later frozen for sensory analysis. A taste panel assessed beef odours and flavours intensities and overall acceptability in grilled meat. Result showed influence of previous production system to fattening in the percentage of saturated and n-3 fatty acids, being bigger the proportion of n-3 in the extensive systems and bigger the SAT % and n-6 / n-3 relationship in the semi-intensive system. In sensory analysis it had not effect of the previous to fattening production system. Only, it was found effect of ageing, which increase statistically the beef odour and flavour, tenderness and global acceptability.
Two different techniques for obtaining extracts representing the most relevant aroma chemicals fr... more Two different techniques for obtaining extracts representing the most relevant aroma chemicals from grilled lamb have been developed and applied to the elucidation of the gas chromatographic-olfactometric (GC-O) profiles of grilled lamb from fresh or frozen samples. The first one attempted to collect the aroma released during grilling; the second one, the aroma released during eating. The GC-O work was complemented with a thorough isolation and identification study comprising liquid chromatography and dual gas chromatography with simultaneous MS and olfactometric (GC-GC-O-MS) detection.
This paper uses quality theory to identify opportunities for the meat sector that are consistent ... more This paper uses quality theory to identify opportunities for the meat sector that are consistent with trends in meat consumption. Meat consumption has increased and is likely to continue into the future. Growth is largely driven by white meats, with poultry in particular of increasing importance globally. The influence of factors such as income and price is likely decline over time so that other factors, such as quality, will become more important. Quality is complex and consumers' quality expectations may not align with experienced quality due to misconception of certain intrinsic cues. Establishing relevant and effective cues, based on extrinsic and credence attributes, could offer advantage on the marketplace. The use of extrinsic cues can help convey quality characteristics for eating quality, but also for more abstract attributes that reflect individual consumer concerns e.g. health/nutrition, and collective concerns, e.g. sustainability. However, attributes are not of equa...
To identify the most important aroma compounds in 20d-aged meat from castrated heavy Corriedale l... more To identify the most important aroma compounds in 20d-aged meat from castrated heavy Corriedale lambs fed one of four diets, grilled loin samples were subjected to a dynamic headspace-solid phase extraction (DHS-SPE) and gas chromatography-olfactometry (GC-O). Most of the important odorants were aldehydes and ketones. To evaluate the effect of finishing diet on carbonyl compounds, a derivatization of the headspace carbonyls using o-[(2,3,4,5,6-pentafluorophenyl)methyl]hydroxylamine hydrochloride (PFBHA) and analysis by GC-MS was conducted. Diet did not affect aliphatic saturated aldehydes. The meat from lambs finished on pastures, without a concentrate supplement, had very low concentrations of lipid-derived unsaturated aldehydes and ketones and Strecker aldehydes, possibly because of the protective effect of antioxidants that occur in the diet naturally. Lamb flavour was related to the concentration of heptan-2-one and oct-1-en-3-one, but rancid or undesirable flavours were not related to the abundance of carbonyl compounds.
ABSTRACT The effects of different freezing methods (nitrogen freezing tunnel, air blast freezer a... more ABSTRACT The effects of different freezing methods (nitrogen freezing tunnel, air blast freezer and home freezer) and frozen storage duration (1 month and 10 months) have been studied by sensory analyses and chemical analyses of odor-active compounds. The sensory analyses showed that fresh meat was significantly (p < 0.05) juicier than frozen meat. Meat frozen in the air blast freezer (ABF) and stored during 10 months had the highest lamb flavor intensity, significantly different from meat frozen in a home freezer (stored for 1 and 10 months) or in a nitrogen tunnel and stored for 1 month. The fresh sample was characterized by lower levels of Strecker aldehydes, 2-phenoxyethanol, cresols and to a lesser extent 2-methylbenzaldehyde, and higher levels of furaneol, which was not even detected in frozen samples. These compounds, together with the relative levels of octanoic acid and ethyl hexanoate, could be used as markers to detect whether lamb meat has been frozen. In chemical terms, the ABF samples were the most similar to fresh meat. Remarkably, in most cases the relative chemical aroma composition had no significant differences as a result of freezing. This helps explain the high sensory similarity observed. Only pyrazine levels changed significantly with frozen storage duration. No oxidation aromas or rancidity have been detected in fresh or frozen lamb.
Introduction - Winery by-products, which may constitute undesirable waste, can be used as feeding... more Introduction - Winery by-products, which may constitute undesirable waste, can be used as feeding supplements in ruminants, but they could modify product quality. Aim - To investigate the effect of wine by-products added to lactating ewes feeding on the ewe’s welfare, milk quality and their suckling lamb performance, carcass and meat quality. Material and methods - A total of 42 Chamarita breed ewes were allocated in one of three experimental diets: a control, based in concentrates without added by-product, and diets supplemented with either 10% grape pomace or 5% grape seed on a dry matter basis, during middle gestation and lactation. Ewe’s physiological welfare indicators and milk quality were assessed, and daily gain, carcass and meat quality (pH, cooking and thawing losses, texture and colour) in their suckling lambs were analysed. Results and discussion - Compared to the control group, cortisol levels was higher in the ewes fed pomace; whereas creatine kinase and non-esterified...
20 young males from Gasconne breed originated from two different production systems (extensive an... more 20 young males from Gasconne breed originated from two different production systems (extensive and semi-intensive) were fattened until 510 kg (slaughter live weight). After 24 hours Longissimus dorsi was obtained. For each animal one 1,5 cm steak was frozen for posterior fatty acids analysis (Bligh & Dyer) and three 2 cm steaks were aged during 1, 7 and 21 days at 4oC and later frozen for sensory analysis. A taste panel assessed beef odours and flavours intensities and overall acceptability in grilled meat. Result showed influence of previous production system to fattening in the percentage of saturated and n-3 fatty acids, being bigger the proportion of n-3 in the extensive systems and bigger the SAT % and n-6 / n-3 relationship in the semi-intensive system. In sensory analysis it had not effect of the previous to fattening production system. Only, it was found effect of ageing, which increase statistically the beef odour and flavour, tenderness and global acceptability.
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