Effect of Dietary Grape Pomace on Fattening Rabbit Performance, Fatty Acid Composition, and Shelf Life of Meat.

The use of agroindustry by-products in animal diets allows the use of residues that are not fit for human consumption. In this study, it was investigated whether fattening commercial rabbits during 30 days with a non-medicated feed, with 20% addition of grape pomace (GPD), affected production traits and the fatty acid composition, antioxidants properties, and the shelf life of the meat compared to a conventional strategy (CON). Furthermore, it was tested, by chromatographic analysis, whether this alternative diet allowed the transfer of phenolic compounds to the meat. Thirty-six weaned rabbits were allotted to the two treatments. In each treatment, 18 rabbits were fattened in three indoor cages, each housing three males and three female rabbits. No significant differences were found in live weights (p > 0.05), but the feed conversion rate and carcass weight and yield were found to be impaired in the GPD group (p ≤ 0.05). The GPD group had a higher intramuscular fat percentage (2.01 vs. 1.54), improved polyunsaturated/saturated fatty acids ratio (0.75 vs. 0.66), and better atherogenicity (0.71 vs. 0.83) and thrombogenicity (1.14 vs. 1.24) indexes, while the n-6/n-3 ratio was higher (25.4 vs. 20.3). Total volatile basic nitrogen in meat was lower in the GPD group (p = 0.01), suggesting a delayed spoilage. However, no improvements in total phenolic content, antioxidant capacity, reducing power, and lipid oxidation (p > 0.05) were found in the meat. Even though the GPD pellets offered to the animals had several grape-derived phenolic compounds, and higher antioxidant properties compared to the CON diet, none of the phenolic compounds detected in feeds were detected in the meat samples.

Perception of beef quality for Spanish and Brazilian consumers.

Understanding the priorities of beef consumers is important for planning strategies to attract and maintain each customer. Using self-administered interviews with Spanish and Brazilian adults who regularly consume beef, we analyzed their purchasing behaviors in relation to their perceptions and priorities regarding beef quality that guide their choices. The current study identifies the influences of information (labeling and marketing) requirements, concerns about humane production systems, and the intrinsic characteristics of beef. To evaluate the data extracted from the interviews, the questions were grouped into four main factors. While extrinsic factors are the highest valued in both Spain and Brazil, those such as beef freshness and tenderness present inverse concerns between the two countries based on cultural dissimilarities. The data also reveals a clear symmetry among consumers who increasingly seek specific pre-purchase information and products with guaranteed superior quality. Despite other characteristics that differentiate developed and developing countries, the perceptions of quality among consumers in Spain and Brazil are decidedly similar.

Differentiating Breast Myopathies through Color and Texture Analyses in Broiler.

Wooden breast (WB), white striping (WS) and spaghetti meat (SM) are breast myopathies of the Pectoralis major that greatly affect meat quality in broilers. To differentiate color and texture characteristics with instrumental methods, some of them applied for the first time in this species, 300 carcasses were randomly chosen from an abattoir from five different flocks from the same farm, at a rate of 60 carcasses from each flock. Twenty-four hours after slaughter, both side breasts were dissected, and yields calculated. Color was measured on the surface of the breast with a spectrocolorimeter and reflectance values obtained. Texture was measured on raw meat with a modified compression test that hinders the fiber from expanding transversally and a texture profile analysis (TPA) and also on cooked meat with a Warner-Bratzler shear and a TPA. Color differs between severity degrees, increasing redness (from -1.77 to -1.32 in WB) and, especially, yellowness (from 5.00 to 6.73 in WS) and chroma (from 5.75 to 7.22 in SM) with the severity of the myopathy. The subtraction R630 minus R580 was found to be a useful index to differentiate breast myopathies degrees. The modified compression test can be considered an effective tool to assess the hardness of different structures in each myopathy. Texture differences in the myopathies are better assessed in raw than in cooked meat.

Behaviour and welfare of fattening lambs supplemented with varying sizes and types of straw.

The aim was to evaluate the effect of size (long or chopped wheat straw), type (barley or wheat) and presence/absence (1 week) of straw supplementation on behaviour and welfare of fattening lambs. Sixteen lambs (65 days) were individually housed to be used in two simultaneous experiments (8 lambs each) for 5 weeks of fattening. After a habituation period, they were offered straw that differed either in size (Experiment 1) or type (Experiment 2), which was followed by a week without straw and then reallocation of straw. Maintenance behaviours, play and stereotypies were analysed using video recording. Physiological stress responses were measured using blood samples taken at the end of the week without straw and after the reallocation of the straw. A preference test was performed during the last week. Concentrate and roughage consumption, average daily gain and conversion index were estimated. Lambs provided with long straw spent more time eating forage, playing and performed fewer stereotypies (Experiment 1). Lambs given wheat straw increased their play behaviour compared with those given barley straw, without affecting stereotypies (Experiment 2). When the straw was removed, lambs performed more behaviours associated with stress; however, this was not reflected in blood stress indicators. Lambs clearly preferred long straw over chopped straw, but no clear preference was observed between wheat and barley straw. The amount of forage intake was consistent with the time spent eating forage, but the amount of concentrate intake did not vary with eating concentrate behaviour, since the amount of concentrate intake was higher when the straw was removed, especially in Experiment 2. Our results show that size more than type of straw supplement impact the behaviour of lambs. Long straw reduces the stereotypies and increases play. This may improve the welfare and performance of fattening lambs, adding ethical value to a highly appreciated product.

Number of consumers and days of display necessary for the assessment of meat colour acceptability.

Visual assessment is regarded as the gold standard to evaluate meat colour shelf-life, but it is costly and time consuming. To address this issue, this paper aims to evaluate the number of consumers and days of display that are necessaries in order to assess the colour shelf-life of meat, presented with different methods, all using images. Photographs of thirty-six lamb steaks were taken just after cutting (day 0) and on each of the following days until the 14th day of display under standardized conditions. Images were presented in three different manners: 1) with days of display and animals in random order (Random); 2) days of display in sequential and animals in random order (Sequential); and, 3) days of display and animals in sequential order (Animal); they were presented to 211 consumers who evaluated visual acceptability on a 9-point scale. At day zero, visual acceptability scores were the highest in Animal, followed by Sequential, and then by the Random (P < .05) method. Scores decreased over time for all methods tested (P < .05). The Random method presented the highest standard deviation; however, an increase in standard deviation among consumers along days of display was observed for all methods tested (P < .05). Shelf-life determined by regression varied according to the method of presentation (7.83, 7.00 and 7.54 days for Random, Sequential and Animal, respectively). A minimum number of 4 day points before and 4 day points after neutral scores had been reached (scores = 5.0) were necessary in order to obtain a robust model. The minimum number of required consumers (α = 0.05; d = 0.1 and ß = 0.2 or 0.1) varied according to methodology: it was 81 to 109 consumers for Random, 69 to 92 for Sequential, and 55 to 74 for Animal. Our study indicates that an optimal number of days and evaluators can be calculated depending on the manner of sample presentation. These findings should be taken into account in further studies that aim to balance data reliability with the cost involved in meat colour analyses.

Development of a robust HS-SPME-GC-MS method for the analysis of solid food samples. Analysis of volatile compounds in fresh raw beef of differing lipid oxidation degrees.

This work presents a headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) method for the analysis of solid food samples in extended experiments. The final procedure was used to quantify 30 volatile compounds in fresh beef. The strategy adds robustness to the classic SPME methods for solid samples, by including a control solution that solves several challenges. The control solution contained one representative compound for each studied family of beef, and two internal standards. Response factors were calculated for each family, and were subsequently applied to every compound belonging to the same family. This strategy allowed control of the quantification procedure even when the fibre, column or control solution changed. Repeatability and reproducibility had relative standard deviation values below 17%, except for phenylacetaldehyde, (E)-2-nonenal and (E,Z)-2,4-decadienal. Although the method described here was applied to animal products, it has also been successfully used to distinguish between samples from different lipid oxidation stabilities.

Ageing and retail display time in raw beef odour according to the degree of lipid oxidation.

This study aims to assess the changes in beef aroma over time when steaks from pre-aged knuckles are stored in retail display under high oxygen conditions for 15 or 22days in vacuum conditions. Odorous volatile compounds were analysed by solid-phase microextraction/gas chromatography-mass spectrometry. Results were grouped as low, medium and high oxidative groups according to thiobarbituric acid reactive substances values after 9days of display. The intensity of off-odours in the raw meat increased with ageing and display time and oxidative groups. Based on correlations between the variables and regressions of the compounds through display, eight compounds were proposed as odour shelf-life markers. Among them, five were most sensitive and precise in all oxidative groups: 1-hexanol in meat aged for 15days, ethyl- octanoate and 2-pentylfuran in meat aged for 22days, and pentanoic and hexanoic acids in the two studied ageing times.

Beef quality attributes: A systematic review of consumer perspectives.

Informed by quality theory, this systematic literature review seeks to determine the relative importance of beef quality attributes from a consumer perspective, considering search, experience and credence quality attributes. While little change is anticipated in consumer ranking of search and experience attributes in the future, movement is expected in terms of ranking within the credence category and also in terms of the ranking of credence attributes overall. This highlights an opportunity for quality assurance schemes (QAS) to become more consumer focused through including a wider range of credence attributes. To capitalise on this opportunity, the meat industry should actively anticipate new relevant credence attributes and researchers need to develop new or better methods to measure them. This review attempts to identify the most relevant quality attributes in beef that may be considered in future iterations of QAS, to increase consumer satisfaction and, potentially, to increase returns to industry.

The effects of potato and rice starch as substitutes for phosphate in and degree of comminution on the technological, instrumental and sensory characteristics of restructured ham.

The effects of sodium tripolyphosphate (STPP), two sources of starch (potato starch: PS and rice starch: RS) and comminution degree (CD) on the technological, instrumental and sensory characteristics of reformed hams were studied using response surface methodology. Both starches reduced cook loss and decreased ham flavour intensity, but RS had stronger effects on instrumental measures of texture, while PS was associated with improved juiciness when low/no added STPP was included. Coarsely ground meat, processed 100% with the kidney plate was associated with slightly increased cook loss, reduced texture profile analysis parameters and a more intense ham flavour compared to the other treatment (80% ground with a kidney plate plus 20% with a 9mm plate). STPP was the sole factor affecting overall liking. If starch is included in the formulation, the standard level of STPP (0.3%) can be reduced by half with no increase in cook losses, but some decline in sensory quality cannot be avoided.

The effect of partial-fat substitutions with encapsulated and unencapsulated fish oils on the technological and eating quality of beef burgers over storage.

The effects of fat substitution (≤ 15%) with commercial encapsulated and unencapsulated fish oils on the technological and eating quality of beef burgers over storage [modified atmosphere packs (80% O2:20% CO2); constantly illuminated retail display at 4 °C; for 15 days] were studied using design of experiment (DOE). Burger formulations comprised beef shin (59.5%), salt (0.5%), vitamin E (0.015%) combined with varying levels of beef-fat/fish oils depending on the treatment. Increasing amounts of encapsulated and unencapsulated fish oils in burgers increased polyunsaturated fatty acid content (P < 0.001). Storage decreased (P < 0.001) a* values, which was in agreement with oxymyoglobin data. Vitamin E inclusion in burgers resulted in higher (P < 0.01) oxymyoglobin values. TBARS values increased (P < 0.001) over storage as expected. Fat substitution with unencapsulated oils increased cook loss (P < 0.001) and decreased hardness (P < 0.05) compared to other treatments. Optimisation predicted a burger formulation with 7.8% substitution in beef-fat with encapsulated fish oil. Panellists scored the optimised burger formulation (P < 0.05) lower than controls for overall acceptability.

Meat consumption: trends and quality matters.

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 equal value to all consumers. Thus consumer segmentation and production differentiation is needed.

Modelling the influence of inulin as a fat substitute in comminuted meat products on their physico-chemical characteristics and eating quality using a mixture design approach.

The effects of fat substitution using two commercial inulin products on the physico-chemical properties and eating quality of a comminuted meat product (breakfast sausage) were modelled using a specialised response surface experiment specially developed for mixtures. 17 treatments were assigned representing a different substitution level for fat with inulin. Sausages were formulated to contain pork shoulder, back fat/inulin, water, rusk and seasoning (44.3, 18.7, 27.5, 7 and 2.5% w/w). Composition, sensory, instrumental texture and colour characteristics were assessed. Fructan analysis showed that inulin was unaffected by heat or processing treatments. Models showed increasing inulin inclusions decreased cook loss (p<0.0017) and improved emulsion stability (p<0.0001) but also resulted in greater textural and eating quality modification of sausages. Hardness values increased (p<0.0001) with increasing inulin concentration, with panellists also scoring products containing inulin as less tender (p<0.0112). Optimisation predicted two acceptable sausage formulations with significantly lower fat levels than the control, which would contain sufficient inulin to deliver a prebiotic health effect.

The development of aromas in ruminant meat.

This review provides an update on our understanding of the chemical reactions (lipid oxidation, Strecker and Maillard reactions, thiamine degradation) and a discussion of the principal aroma compounds derived from those reaction or other sources in cooked meat, mainly focused on ruminant species. This knowledge is essential in order to understand, control, and improve the quality of food products. More studies are necessary to fully understand the role of each compound in the overall cooked meat flavour and their possible effect in consumer acceptability.

Gas chromatographic-olfactometric aroma profile and quantitative analysis of volatile carbonyls of grilled beef from different finishing feed systems.

UNLABELLED: In this study, the important odor impact volatiles generated in the meat of grilled beef loin muscle were characterized. Animals were finished in 4 different diet systems: T1, pasture (a mixture of Medicago sativa, Trifolium repens, and Festuca arundinacea); T2, pasture supplemented with cracked corn grain (offered at 0.6% live weight, LW); T3, pasture supplemented with cracked corn grain (offered at 1.2% LW); and T4, concentrate (pellets with 85% corn and 12.8% sunflower, on a dry-matter basis) plus alfalfa hay (both ad libitum). Aroma compounds were assessed by dynamic headspace-solid phase extraction (DHS-SPE) and gas chromatographic-olfactometric (GC-O) analysis. Most odorants were carbonyl compounds, some of them reaching high GC-O scores, especially 1-octen-3-one, (E)-2-octenal, methional, and hexanal. A specific quantitative analysis of ketones and aldehydes was conducted through their derivatization with o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride directly on the headspace trap and analyzed by GC-MS, with the purpose of studying the effect of finishing diet systems. From the 23 carbonyl compounds quantified, 2 were especially affected by the diet system; methional was higher in the treatment based on concentrates, whereas (E,E)-2,4-heptadienal was higher in the treatment based only in pastures. The results are discussed considering previous published productive and quality traits. PRACTICAL APPLICATION: The knowledge of how production factors, such as animal feeding, can affect the flavor of meat is of significant interest toward in achieving a high-quality and differentiated product. The development of more specific and efficient methodologies is necessary to analyze meat aroma compounds, which would be used as routine analysis, that is for product authentication. In the future, the use of this analysis would allow producing and designing specific foods according to different markets.

Color, lipid oxidation, sensory quality, and aroma compounds of beef steaks displayed under different levels of oxygen in a modified atmosphere package.

UNLABELLED: High oxygen modified atmosphere packaging (MAP) is currently used by the industry to maintain an attractive color in fresh meat. However, it can also promote lipid oxidation and sensory changes. The aim of this study was to compare the quality of beef steaks displayed under different levels of oxygen. For that purpose, meat was stored with 50%, 60%, and 80% of oxygen for 4 and 8 d at retail conditions. A control treatment with steaks vacuum packaged, without exposure to retail display, was included, and color, lipid oxidation, organoleptic characteristics, and aroma compounds were analyzed. Steaks displayed under high oxygen MAP with 50% of oxygen showed the lowest color stability, according to hue values. Higher oxygen levels did not necessarily correspond with higher rancidity levels in the raw meat. Thiobarbituric Acid Reacting Substances (TBARS) values were higher than 2.2 mg malonaldehyde (MDA)/kg muscle in all the samples displayed for 8 d at retail conditions. These samples exhibited the highest intensities of rancid and the least intense beef odors and flavors. The ketones: 2,3-butanedione, 2-octanone, 2,3-pentanedione, 2-heptanone, 4-methyl-2-pentanone, and the aldehydes: pentanal, 2-methyl-butanal, and 2-furfurylthiol, 1-octen-3-ol and 2-methylpropyl-acetate, were proposed as candidates for the aroma differences between the cooked beef steaks stored under vacuum and high oxygen packs. PRACTICAL APPLICATION: High oxygen modified atmosphere packaging (MAP) is used to increase shelf-life and color at the retail level. However, oxygen deteriorates faster some quality attributes, being a contributor to lipid oxidation that could be perceived at consumption. This study attempts to find the best gas composition in a MAP in order to maintain the color, minimizing the oxidation. Aromatically relevant chemicals have been analyzed by gas olfactometry-gas chromatography as a key to measure beef oxidation after display.

Relationship between odour-active compounds and flavour perception in meat from lambs fed different diets.

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.