Extended ageing time and temperature effects on quality of sub-primal cuts of boxed beef

[EN]Most of the information indicating ageing improves tenderness has been collected on the loin and rib-eye muscles over relatively short ageing times, assuming that all muscles will react similarly. In the present study, the effect of extended ageing times on instrumental texture (56 d) and sensory characteristics (42 d) of six different beef sub-primals [striploin (SL), inside round (IR), outside round (OR), eye of round (ER), blade eye (BE) and chuck tender (CT)] was studied. The effects of two ageing temperatures (1and 58C) were also compared. In general, ageing increased tenderness (P<0.05) of SL, BE, ER and CT sub-primals, although BE shear force increased after 42 d of ageing. On the other hand, ageing had no effect on IR tenderness (P<0.05) and resulted in a decrease in tenderness of OR (P<0.05) until day 35, with a later increase after 42 d of ageing. Increasing ageing temperature (58C) had limited effect on tenderness, but ageing time and temperature increases led to lower flavour and higher off-flavour intensity (P<0.05) of the studied sub-primals. These results suggest that cutspecific maximum ageing times and rigid adherence to temperature maximums would be of benefit to optimize postslaughter processes and meat quality[FRE]La plupart des données indiquant que le rassissement améliore la tendreté ont été recueillies sur les muscles de la longe et du faux-filet sur un temps relativement court, partant de l’hypothèse que les muscles réagissent tous de la même manière. Cette étude examine l’incidence d’un rassissement prolongé sur la texture (56 jours) et sur les propriétés organoleptiques (42 jours) de six coupes sous-primaires de boeuf [contre-filet (CF), intérieur de ronde (IR), extérieur de ronde (ER), noix de ronde (NR), noix de palette (NP) et bas de tendre (BT)]. Les auteurs ont aussi comparé l’effet de deux températures de rassissement (1et 58C). Dans l’ensemble, le rassissement accroît la tendreté (P<0,05) des morceaux CF, NP, NR et BT, bien que la résistance de la NP au cisaillement augmente après 42 jours. Parallèlement, le rassissement n’a aucune incidence sur la tendreté de l’IR (P<0,05) et diminue celle de l’ER (P<0,05) jusqu’au 35e jour, avant de l’amé liorer passé le 42e jour. Augmenter la température du rassissement (58C) a des effets restreints sur la tendreté , mais ajouteé à un rassissement plus long, la hausse de température atte´nue la saveur et intensifie l’arrière-goût (P<0,05) des pièces de viande examinées. Ces ré sultats laissent croire que l’établissement d’une dureé de rassissement adapteé au morceau et un strict respect de la température maximale optimiseraient les opérations suivant l’abattage et la qualité de la viande

Fatty acid composition of beef steers as affected by diet and fat depot

Abstract Subcutaneous and perirenal fatty acid (FA) profiles were compared in steers fed a control diet (70 : 30 red clover silage (RC) : barley concentrate), a diet with sunflower seed (SS) substituted for barley, and diets with 15% or 30% wheat dried distillers&apos; grain with solubles (DDGS-15 and DDGS-30) substituted for RC and SS. Perirenal fat (PRF) versus subcutaneous fat (SCF) had greater proportions of total saturated FA (SFA) and branched chain FA (BCFA), and lower proportions of total and major cis-monounsaturated FA (c-MUFA). Addition of SS to the diet did not change the proportions of total and major c-MUFA and n-6 polyunsaturated FA (PUFA), but led to decreases in the proportions of total and major SFA, BCFA and n-3 PUFA. Progressive substitutions with DDGS led to no further changes in the proportions of total and major SFA and n-3 PUFA, but decreased the proportions of BCFA and c9-16:1, and increased the proportions of c9-18:1 and n-6 PUFA. Feeding SS and DDGS-15 diets yielded the largest proportions of total and major t-18:1 (t11-and t13-/t14-18:1) isomers in PRF and conjugated lineolic acid (CLA) isomers (t7,c9-and t9,c11-18:2) in SCF, but responses were diminished when feeding the DDGS-30 diet. Subcutaneous fat versus PRF from steers fed SS and DGGS diets had larger proportions of non-conjugated 18:2 biohydrogenation products (i.e. atypical dienes) than the control diet. Overall, feeding SS and DDGS-15 diets raised the proportions of t11-18:1 in PRF and c9,t11-18:2 in SCF, which have potential human health benefits, but feeding DDGS-30 was less effective

Predicting the content of polyunsaturated fatty acids and biohydrogenation products in subcutaneous fat of beef cows fed flaxseed by near infrared reflectance spectroscopy

1 página.-- Proceedings of the Canadian Meat Science Association Technical Symposium (Halifax, Canadá, 6-7 octubre de 2011)Today, consumers are interested in fat composition as scientific evidence suggests that diets high in saturated fat are associated with an increased risk of cardiovascular disease. Techniques to quantify fatty acids (FA) in meat are costly and time-consuming. Near infrared reflectance spectroscopy (NIRS) is a rapid and non destructive method. The aim of this study was to examine the ability of NIRS to estimate the concentration of polyunsaturated FA and their biohydrogenation products in subcutaneous fat from cows fed flaxseed. Subcutaneous fat samples at the 12th rib of 62 cows were collected and stored at -80ºC. After thawing, 32 spectra from each intact sample were collected, then averaged, over a NIR spectral range from 400 to 2498 nm at 31ºC (warm samples) and 2ºC (cold samples), and then analyzed for FA profiles. NIRS calibrations on warm samples, tested by cross-validation, showed high predictability for most of the n-3 (R2: 0.81- 0.86; RMSECV: 0.11-1.56 mg·g-1 fat) and linolenic acid biohydrogenation products such as conjugated linolenic acids, conjugated linoleic acids (CLA), non-CLA dienes and trans-monounsaturated FA with R2 (RMSECV, mg·g-1 fat) of 0.85-0.85 (0.16-0.37), 0.84-0.90 (0.21-2.58), 0.90 (5.49) and 0.84-0.90 (4.24-8.83), respectively. When spectra were obtained from cold samples NIRS predictability was lower than that for warm samples, probably due to a less homogeneous distribution of fat throughout the cells and more air bubbles, or to reduced molecular vibration due to the cooler temperature. NIRS could discriminate 100% of subcutaneous fat samples from cows fed different diets (with or without flaxseed). These data support that NIRS has the potential to be used as a fast and accurate predictor of content of linolenic acid and its biohydrogenation products in subcutaneous fat of beef cows. Nevertheless, further studies are required to test its ability during on-line operations in an abattoir.Peer reviewe

Near infrared spectroscopy prediction of polyunsaturated fatty acids and biohydrogenation products in perirenal adipose tissue from cattle fed sunflower or flaxseed

4 páginas, 2 tablas.- Trabajo presentado al 58th International Congress of Meat Science and Technology (Montreal, Canadá, Aug. 12-17, 2012).The objective of this study was to test the potential of near infrared reflectance spectroscopy (NIRS) to estimate the proportion of polyunsaturated fatty acids (FA) and their biohydrogenation products in perirenal adipose tissue (PrFat) from cattle fed sunflower or flaxseed. PrFat from 63 steers was collected immediately after skinning, scanned at 37 °C over a NIR spectral range from 400 to 2498 nm on benchtop equipment, and analysed for FA composition. NIR calibrations, tested by cross-validation, showed high predictability for most of the total n-3, conjugated linolenic acids, t,t-conjugated linoleic acids (CLA), non-CLA dienes and trans-monounsaturated FA, with R2 and root mean square error of crossvalidation (RMSECV, %) of 0.95 (0.07-0.08), 0.86- 0.89 (0.01-0.09), 0.93 (0.07), 0.89 (0.46) and 0.92-0.93 (0.87-1.29), respectively. The results show NIRS to be a useful technique for the early, fast and relatively inexpensive estimation of proportion of FA with potential human health effects.Peer reviewe

Palatability of Beef from Cattle Fed Extruded Flaxseed before Hay or Mixed with Hay

This study was undertaken to evaluate the eating quality of steaks and hamburgers (80/20 to perirenal fat) with enhanced profiles of potentially healthy fatty acids. The profile of health favorable fatty acids (n-3, vaccenic and rumenic) was improved in beef by feeding co-extruded flaxseed (flaxseed, peas, and alfalfa) and alfalfa-grass hay as a total mixed ration (TMR), and further enhanced by feeding co-extruded flaxseed before alfalfa-grass hay (Non-TMR). Compared to TMR, feeding steers the Non-TMR resulted in tougher steaks ( < 0.05) with lower beef flavor ( < 0.01) and greater off-flavor ( < 0.01) intensity to an extent that might be detectable by consumers. High levels of -monounsaturated fatty acids, mainly of vaccenic acid, were associated with a fishy off-flavor, although actual changes in flavor may relate to correlated combined effects of conjugated fatty acids, atypical dienoic acids and ɑ-linolenic acid. Diet had no significant effect on sensory attributes of hamburgers, but when panelists described off-flavors, they noted more ‘other’ off-flavors ( < 0.05) with fishy and stale/cardboard notes being more prominant in Non-TMR hamburgers. Overall, beef samples with threshold levels of vaccenic acid over 6.12% of total fatty acids resulting from feeding flaxseed products, while of potentially greater health benefit, may pose challenges in terms of eating quality. Areas worthy of further investigation to ensure acceptable eating quality might be the influence of ageing on antioxidant capacity in beef with enhanced fatty acid profiles, and the potential use of protective packaging to limit deterioration