Dietary fatty acid intervention of lactating cows simultaneously affects lipid profiles of meat and milk

BACKGROUND: The present study investigated tissue‐specific responses of muscle and mammary gland to a 10 week intervention of German Holstein cows (n = 18) with three different dietary fat supplements (saturated fat; linseed oil or sunflower oil plus docosahexaenoic acid‐rich algae) by analysing fatty acid profiles and quality parameters of meat and milk. RESULTS: Plant oil/algae intervention affected neither fat content nor quality parameters of meat but decreased fat content and saturated fatty acid amounts of milk. Linseed oil/algae intervention caused significantly higher concentrations of C18:3n‐3 (meat, 1.0 g per 100 g; milk, 1.2 g per 100 g) and C22:6n‐3 (meat, 0.3 g per 100 g; milk, 0.14 g per 100 g). Sunflower oil/algae intervention increased n‐6 fatty acid contents in milk (4.0 g per 100 g) but not in meat. Elevated amounts of C18:1trans isomers and C18:1trans‐11 were found in meat and especially in milk of plant oil/algae‐fed cows. C18:1cis‐9 amounts were found to be increased in milk but decreased in meat after plant oil/algae intervention. CONCLUSION: The present study demonstrated that dietary fatty acid manipulation substantially shifted the fatty acid profiles of milk and to a lesser extent of meat, whereas meat quality traits were not affected. Indications of tissue‐specific responses of mammary gland and muscle were identified. Copyright © 2012 Society of Chemical Industry     

A COMBINATION OF GLUTAMINASE AND pH CONTROL PREVENTS THE NONENZYMATIC CONVERSION OF l-GLUTAMINE INTO l-2-PYRROLIDINE-5-CARBOXYLIC ACID IN FOOD PROCESSING

A strategy using Alicyclobacillus F‐62 glutaminase was established to minimize the nonenzymatic production of l ‐2‐pyrrolidine‐5‐carboxylic acid (l ‐pyroglutamic acid, savorless amino acid) and maximize the enzymatic production of l ‐glutamic acid (savorous [umami] amino acid) from l ‐glutamine in food‐protein processing. The nonenzymatic production rate of l ‐pyroglutamic acid was influenced by pH and temperature, and decreased over a pH range of 4–6 at 30C. Under optimum conditions (30C and pH 5.0), the l ‐glutamic and l ‐pyroglutamic acids obtained from 1 mM l ‐glutamine in the presence of glutaminase from Alicyclobacillus F‐62 were 0.96 and 0.03 mM, respectively. This novel method is useful for the efficient production of l ‐glutamic acid during food‐protein processing.     

Low‐Fat Beef Patties with Augmented Omega‐3 Fatty Acid and CLA Levels and Influence of Grape Seed Extract

The effects of raising the omega‐3 fatty acid (FA), conjugated linoleic acid (CLA), or omega‐3 FA plus CLA levels on beef by means of dietary supplementation and of adding grape seed extract (250 mg/kg meat product) in beef patties stored at 2 ± 1 °C in aerobic packaging under simulated retail display conditions for 6 d was evaluated by measuring the thiobarbituric acid reactive substances (TBARS), pH, and instrumental color measurement values and by means of sensory analysis. The pH, instrumental color measurements, and sensory attribute values for patties made from beef with augmented omega‐3 FA and/or CLA contents were similar to the values for the control patties made from beef from animals fed a conventional diet. Adding GSE lowered oxidation levels on day 6 (P < 0.001) and did not affect the instrumental color or sensory analysis results during the display period. This suggests that omega‐3 FA and CLA‐augmented beef could be used to make low‐fat beef patties having characteristics similar to those of conventional beef patties while being more in keeping with currently recommended nutritional guidelines.     

Effect of oil sources and vitamin E levels in the diet on the composition of fatty acids in rooster thigh and chest meat

The aim of this study was to evaluate the inclusion of different oil sources and dietary supplementation with vitamin E on the composition of fatty acids in rooster meat. Two hundred and forty 30‐week‐old White Leghorn roosters were distributed in a completely randomized factorial arrangement of 5 × 2, using five oil sources (sunflower, soybean, canola, linseed and fish) and two levels of antioxidant (30 and 400 mg vitamin E kg^?1 of diet). The intake of fish and canola oil in the diet reduced (P < 0.05) the content of saturated and unsaturated fatty acids in the thigh meat. Amongst the unsaturated fatty acids in the thigh, the fish and canola oil reduced (P < 0.05) the level of ω6 fatty acid, with a consequent decrease in the ratio ω6:ω3. The diet with fish oil increased (P < 0.05) the content of C22:6ω3 in the thigh meat. The use of linseed oil resulted in a significant reduction of the ratio of ω6:ω3 fatty acid in the thigh. The use of soybean oil in the diet increased (P < 0.05) the content of saturated and unsaturated fatty acids in the thigh, specifically in the content of ω6. The inclusion of vitamin E increased the polyunsaturated fatty acids in the chest meat, such as C18:3ω3, C20:5ω3 and C22:6ω3. Copyright © 2004 Society of Chemical Industry     

Influence of nitrogen on the biological aging of sherry wine

Nitrogen compounds are essential to the growth and metabolism of yeasts. The uptake and metabolism of nitrogen compounds by Saccharomyces cerevisiae depend not only on the strain and its physiological condition, but also on the chemical and physical properties of its environment. The effect of the addition of different amino acids (L ‐proline, L ‐threonine, L ‐arginine, L ‐glutamic acid, L ‐leucine and L ‐valine) to nitrogen‐depleted natural or nitrogen‐free synthetic wine on the cell growth, flor velum formation and sherry wine compound production was investigated under controlled biological aging by S. cerevisiae var. capensis strain G1 a typical flor yeast. The formation of flor velum was dependent on particular amino acid, oxygen availability and the composition of wine. Consumption of glycerol was related with the cell growth; in contrast, acetaldehyde tended to be released. Amino acid supplementation resulted in the release to wine of amino acids, esters and higher alcohols. The amino acid which was released in nearly all cases was L ‐leucine. Addition of L ‐glutamic acid resulted in the release mainly of ethyl acetate, in the case of L ‐leucine isoamyl alcohols were released, and for L ‐valine isobutanol. In the three cases, 1,1‐diethoxyethane was released in large quantities. The findings might indicate that the regulation of metabolism succeeds in the most efficient balancing of the redox potential. Copyright © 2006 Society of Chemical Industry     

不同部位牦牛肉氨基酸、脂肪酸含量分析与营养价值评价

为明确不同部位牦牛肉氨基酸、脂肪酸等营养物质含量,采集西藏那曲牦牛的上脑、里脊、外脊、米龙、臀肉、腱子肉、腹肉、肩肉及胸肉9 个部位分割肉,测定其蛋白质、脂肪、灰分、氨基酸和脂肪酸组成。结果表明：不同部位牦牛肉的蛋白质含量为19.30%～24.20%,其中腹肉中蛋白质含量最低,外脊中最高;脂肪含量为1.03%～22.47%,腹肉中脂肪含量显著高于其他各部位,米龙、外脊、臀肉和肩肉中脂肪含量较低,不足1.5%。在测定的18 种氨基酸中,谷氨酸含量最高,其次是赖氨酸、天冬氨酸、亮氨酸和精氨酸;腹肉中氨基酸含量显著低于其他部位（P＜0.05）,9 个不同部位牦牛肉中必需氨基酸占总氨基酸的比例为39.03%～40.00%,与联合国粮农组织/世界卫生组织的推荐值接近;里脊和外脊能够满足所有膳食氨基酸需要,上脑、米龙、臀肉、腱子肉、腹肉、肩肉及胸肉中,缬氨酸是限制性氨基酸。脂肪酸总量由大到小为腹肉＞上脑＞里脊＞臀肉＞外脊＞胸肉＞肩肉＞腱子肉＞米龙,油酸、棕榈酸和硬脂酸是牦牛肉中主要的脂肪酸,二十二碳六烯酸、二十碳五烯酸等n-3脂肪酸含量较少,n-6/n-3比值高于膳食推荐值。以常规营养组分、氨基酸组成和脂肪酸组成分别进行聚类分析,总体可分为腹肉、上脑与其他部位肉三大类。综上所述,不同部位牦牛肉中蛋白质、脂肪、氨基酸及脂肪酸等营养物质含量存在差异。     

Arginine and nitric oxide synthase: Regulatory mechanisms and cardiovascular aspects

l ‐Arginine (l ‐Arg) is a conditionally essential amino acid in the human diet. The most common dietary sources of l ‐Arg are meat, poultry and fish. l ‐Arg is the precursor for the synthesis of nitric oxide (NO); a key signaling molecule via NO synthase (NOS). Endogenous NOS inhibitors such as asymmetric‐dimethyl‐l ‐Arg inhibit NO synthesis in vivo by competing with l ‐Arg at the active site of NOS. In addition, NOS possesses the ability to be “uncoupled” to produce superoxide anion instead of NO. Reduced NO bioavailability may play an essential role in cardiovascular pathologies and metabolic diseases. l ‐Arg deficiency syndromes in humans involve endothelial inflammation and immune dysfunctions. Exogenous administration of l ‐Arg restores NO bioavailability, but it has not been possible to demonstrate, that l ‐Arg supplementation improved endothelial function in cardiovascular disease such as heart failure or hypertension. l ‐Arg supplementation may be a novel therapy for obesity and metabolic syndrome. The utility of l ‐Arg supplementation in the treatment of l ‐Arg deficiency syndromes remains to be established. Clinical trials need to continue to determine the optimal concentrations and combinations of l ‐Arg, with other protective compounds such as tetrahydrobiopterin (BH₄), and antioxidants to combat oxidative stress that drives down NO production in humans.     

Enzymatic Synthesis of l‐Ascorbyl Fatty Acid Esters Under Ultrasonic Irradiation and Comparison of Their Antioxidant Activity and Stability

A series of novel l ‐ascorbyl fatty acid esters were synthesized by catalization of Novozym^® 435 under ultrasonic irradiation and characterized by infrared spectroscopy, electrospray ionization mass spectra, and nuclear magnetic resonance. Their properties especially antioxidant activity and stability were investigated. The results showed that the reducing power, the scavenging activity of hydroxyl radical and 2,2‐diphenyl‐1‐picrylhydrazyl radical were decreased with the increase of the number of carbon atoms in fatty acid. The hydroxyl radical scavenging activity and reducing power of l ‐ascorbyl saturated fatty acid esters were better than that of tert‐butylhydroquinone. The induction period in lipid oxidation of l ‐ascorbyl saturated fatty acid esters and tert‐butylhydroquinone were longer than that of l ‐ascorbyl unsaturated fatty acid esters and l ‐ascorbic acid both in soybean oil and lard. Besides, the l ‐ascorbyl fatty acid esters showed different stabilities in different conditions by comparing with l ‐ascorbic acid, and the l ‐ascorbyl saturated fatty acid esters were more stable than l ‐ascorbyl unsaturated fatty acid esters in ethanol solution.     

Performance,carcass traits,muscle fatty acid composition and meat sensory properties of male Mahabadi goat kids fed palm oil,soybean oil or fish oil

This study examined the effect of palm, soybean or fish oils on the performance, muscle fatty acid composition and meat quality of goat kids. Twenty-four male Mahabadi kids (BW = 19.4 ± 1.2 kg) were divided into three groups according to liveweight and randomly allocated to one of three diets. Animals were fed ad libitum for 84 days. Different dietary fat sources had no effect on performance and/or carcass quality attributes. The soybean oil diet decreased 16:0 and 18:0 concentrations and increased 18:2 and 18:3 and the ratio of PUFA/SFA in the muscle compared with other treatments. Fish oil feeding increased 20:5 n-3 and 22:6 n-3 concentrations and decreased the ratio of n-6/n-3 in the muscle. The results demonstrate that the use of fish oil is a nutritional strategy to improve the health claimable long-chain omega-3 fatty acid content and n-6/n-3 ratio in goat meat without changing the sensory properties or colour of meat.     

Effects of dietary conjugated linoleic acid on the growth performance of chickens and ducks for fattening and fatty acid composition of breast meat

The effects of dietary conjugated linoleic acid (CLA) supplementation on feed intake, growth performance, carcass composition and fatty acid composition of meat tissue were investigated in broiler chickens and Pekin ducks. A total of 108 male chickens for fattening and a total of 96 male and 96 female Pekin ducks were allocated to 3 dietary treatments (0.0, 0.1 and 0.2 % CLA) and fed for 35 or 49 days. The results showed that 0.2 % CLA supplementation in the first 3 weeks improved the daily feed intake of the broilers and the feed to gain ratio, but did not significantly influence body weight, weight and the percentage of abdominal and visceral fat as well as the intramuscular fat in breast muscles. In the duck trial, the daily feed intake was significantly higher through the first 3 weeks of male control group and male 2 g CLA group compared with the female control group. The daily weight gain of all male ducks was significantly higher compared to female ducks of all groups and was not influenced by the CLA supplementation. The feed to gain ratio of the 1 g CLA-male ducks was lowest compared to male and female control ducks and 1 and 2 g CLA female ducks. Supplementing diets with CLA modified the fatty acid composition of breast muscle. The proportion of CLA was increased in broiler meat. In duck meat, the proportions of CLA, saturated fatty acids and polyunsaturated fatty acids were increased and monounsaturated fatty acids were decreased.     

Vitamin E levels,thiobarbituric acid test and sensory evaluation of breast muscles from broilers fed α‐tocopheryl acetate‐ and β‐carotene‐supplemented diets

The objective of this study was to investigate the effect of dietary α‐tocopheryl acetate and β‐carotene supplementation on lipid oxidation of breast meat from broilers fed lard as the fat source. Supplementation of broilers with 100 mg kg^?1 α‐tocopheryl acetate increased the vitamin E levels in raw breast samples significantly (p < 0.05), whereas the presence of 1.5 mg kg^?1 dietary β‐carotene tended to decrease vitamin E deposition. The presence of vitamin E delayed lipid oxidation significantly, but thiobarbituric acid values of samples from broilers fed the β‐carotene‐supplemented diet did not differ from those of control samples. Vitamin E reduced sensory meat rancidity, whilst vitamin E, β‐carotene and their combination modified meat texture. The results show the effectiveness of dietary α‐tocopheryl acetate supplementation in protecting broiler meat against lipid oxidation. Copyright © 2004 Society of Chemical Industry     

Chemical Compositions of Egg Yolks and Egg Quality of Laying Hens Fed Prebiotic,Probiotic, and Synbiotic Diets

A 16‐wk feeding experiment was conducted to investigate the effects of a prebiotic, isomaltooligosaccharide (IMO), a probiotic, PrimaLac®, and their combination as a synbiotic on the chemical compositions of egg yolks and the egg quality of laying hens. One hundred and sixty 16‐wk‐old Hisex Brown pullets were randomly assigned to 4 dietary treatments: (i) basal diet (control), (ii) basal diet + 1% IMO (PRE), (iii) basal diet + 0.1% PrimaLac® (PRO), and (iv) basal diet + 1% IMO + 0.1% PrimaLac® (SYN). PRE, PRO, or SYN supplementation not only significantly (P < 0.05) decreased the egg yolk cholesterol (24‐ and 28‐wk‐old) and total saturated fatty acids (SFA; 28‐, 32‐, and 36‐wk‐old), but also significantly (P < 0.05) increased total unsaturated fatty acids (UFA; 28‐, 32‐, and 36‐wk‐old), total omega 6 and polyunsaturated fatty acids (PUFA), including linoleic and alpha‐linolenic acid levels in the eggs (28‐wk‐old). However, the total lipids, carotenoids, and tocopherols in the egg yolks were similar among all dietary treatments in the 24‐, 28‐, 32‐, and 36‐wk‐old hens. Egg quality (Haugh unit, relative weights of the albumen and yolk, specific gravity, shell thickness, and yolk color) was not affected by PRE, PRO, or SYN supplementation. The results indicate that supplementations with IMO and PrimaLac® alone or in combination as a synbiotic might be useful for improving the cholesterol content and modifying the fatty acid compositions of egg yolk without affecting the quality of eggs from laying hens between 24 and 36 wk of age.     

Sensory evaluations of porcine longissimus dorsi muscle: Relationships with postmortem meat quality traits and muscle fiber characteristics

The objective of this study was to investigate sensory evaluations and their relationships with meat quality measurements and histochemical characteristics in both fresh and cooked pork. Based on the results, postmortem meat quality traits were closely related to almost all the evaluated sensory attributes. With regard to histochemical characteristics, muscle fiber area was related to both fresh- (r = 0.18, P < 0.05) and cooked-meat color (r = −0.24, P < 0.01) as well as abnormal flavor intensity (r = 0.25, P < 0.01), and muscle fiber composition was associated with fresh pork color and taste acceptability after cooking. There were no significant relationships (P > 0.05) between type IIa muscle fiber content and the evaluated sensory attributes; however, good meat sensory quality was partially explained by the percentage of type I fiber.     

卤猪肉加工过程中游离脂肪酸、游离氨基酸及核苷酸变化分析

利用气相色谱质谱联用和高效液相色谱法检测分析了卤猪肉加工过程中游离脂肪酸、游离氨基酸及核苷酸的变化。结果表明,在加工过程中,总游离脂肪酸有效峰面积呈下降趋势,饱和脂肪酸也呈现下降的变化趋势,不饱和脂肪酸含量先增加后减少,在高温煮制1 h时达到最大值。总游离氨基酸的含量在卤猪肉加工过程中变化明显,在原料肉中总游离氨基酸含量为244.39 mg/100 g,其它样品中含量都显著(p0.05)高于原料肉,在二次煮制完成后达到最大值,为349.32 mg/100 g。谷氨酸在成品中的含量达到119.02mg/100 g,占总游离氨基酸的34.12%。呈味核苷酸检测结果显示,在加工过程中5'-IMP和5'-GMP的含量呈现下降趋势。由于加热导致核苷酸热降解,其降解产物肌苷的含量呈现上升趋势,在成品中检测到其含量显著(p0.05)高于原料肉中的含量。本研究结果为改进卤猪肉的生产工艺、提高产品品质提供了理论参考。     

Effects of dietary olive and linseed oil on lipid composition, meat quality, sensory characteristics and muscle structure in pigs

The aim of this study was to alter the fatty acid composition of porcine tissue by accumulating essential fatty acids without adversely affecting carcass composition, muscle structure or meat eating quality. A total of 13 female and 12 castrated Pietrain×German Landrace pigs were fed a basal concentrate diet supplemented with 5% olive oil or 5% linseed oil during the growing-finishing period. Carcass composition and meat quality were not affected by the diet. Feeding linseed oil to pigs significantly increased the relative content of linolenic acid and long chain n-3 fatty acids in lipids of muscle, backfat and heart at the expense of arachidonic acid. Oleic acid was accumulated in muscle, backfat and heart lipids by feeding olive oil. The overall flavour of combined meat/backfat samples from castrates was negatively influenced by linseed oil supplementation compared to supplementation with olive oil. The oxidative stability of muscle lipids was lower in linseed oil-fed pigs compared to olive oil fed pigs. The greater cross section areas of the longissimus muscle of females were caused by an increased diameter of red, intermediate and white fibres.     

Correlations of trained panel sensory values of cooked pork with fatty acid composition,muscle fiber type,and pork quality characteristics in Berkshire pigs

The objective was to examine the relationship of trained panel sensory scores of cooked pork with fatty acid composition, muscle fiber type, and meat quality characteristics from Berkshire pigs. No or few associations were found between the panel sensory scores of cooked meat, especially tenderness attributes, and fatty acid composition; however, intramuscular fat content positively correlated with off-flavor score (r = 0.31). On the other hand, the morphological characteristics of muscle fibers were correlated with panel sensory values. Muscles with smaller cross-sectional area and higher density of fibers were more closely associated with softer, more tender panel scores and a lower number of chews than muscles with larger fiber area and lower density of fibers. The water holding capacity test of filter-paper fluid uptake was moderately correlated with panel scores of softness (r = 0.33), initial tenderness (r = 0.38), chewiness (r = 0.40), juiciness (r = − 0.27), flavor intensity (r = − 0.23), and off-flavor (r = 0.30). Panel sensory values of Berkshire pig meat was moderately related to postmortem meat quality, especially water holding capacity. A more thorough understanding of the relationships between fatty acid composition and muscle fiber type with palatability is needed.     

Physicochemical and fatty acid characteristics of stewed pork as affected by cooking method and time

This study was designed to investigate the effects of cooking on physicochemical and fatty acid characteristics of stewed pork. Pre‐fried or raw pork belly cubes were stewed for 60, 90, 120, 150 or 180 min. After cooking, proximate chemical composition, texture, sensory evaluation, lipid oxidation, fatty acid profiles and cholesterol content were determined. Prolonged cooking time resulted in higher percentages of dry matter, fat and fat loss in stewed cubes (P < 0.01), and pre‐frying also increased fat loss. Tenderness and elasticity values of texture profile analysis and sensory scores were the highest for the cubes stewed for 180 min or by pre‐frying combined with stewing for 150 min. Pre‐frying and extended cooking time significantly increased lipid oxidation (P < 0.01). Cooking modified fatty acid profiles which altered the derived cardiovascular indices, and reduced cholesterol content. Prolonged stewing improved eating quality and most nutritional values of pork belly.     

Amino acid and fatty acid compositions and nutritional quality of muscle in the pomfret, Pampus punctatissimus

The pomfret, Pampus punctatissimus, is an important fisheries resource in China, but little is known about its amino acid and fatty acid compositions. Pomfret muscle contained 18.6% crude protein and 4.95% crude fat. Pomfret protein has a well-balanced amino acid composition, with high amounts of glutamic acid (114 mg/g), lysine (82.8 mg/g), leucine (76.7 mg/g), and aspartic acid (76.0 mg/g). Twenty two fatty acids were found in pomfret oil and saturated fatty acids were the most abundant (48.3%). Palmitic acid (16:0) was the dominant fatty acid, followed by oleic acid (18:1), DHA (22:6n-3), myristic acid (14:0) and stearic acid (18:0), with percentages of 30.5, 26.3, 12.2, 7.37 and 6.86, respectively. The ratio of n-3/n-6 polyunsaturated fatty acids (PUFAs) was 8.04; thus, pomfret muscle is rich in n-3 PUFA.     

Effect of grape dietary fibre on the storage stability of innovative functional seafood products made from farmed meagre (Argyrosomus regius)

Two groups of farmed meagre (Argyrosomus regius) sausages were studied regarding quality changes and antioxidant capacity during a 98‐day storage experiment at 2 ± 2 °C. Control sausages contained 3.9% (w/w) of inner pea dietary fibre (IPDF) and the other group contained 0.9% (w/w) IPDF plus 3.0% (w/w) of antioxidant grape dietary fibre (AGDF). The control and AGDF meagre sausages presented a high nutritional value, given their low caloric content, fatty acid profile, amino acid composition and high DF content. Both products were remarkably stable over storage time. The AGDF had an effective antioxidant capacity, proven not only by the radical scavenging activity (90.0–91.0% vs. 82.1–85.4%) and reducing power (8.13–9.10 mg ascorbic acid equivalent g^‐1 vs. 4.16–4.24 mg ascorbic acid equivalent g^?1) measurements, but also by the lower thiobarbituric acid reactive species (TBARS) values (0.78–1.10 vs. 1.50–2.08 mg malonaldehyde kg^?1) over storage time. AGDF seemed to present antimicrobial effect, since on the 63rd day (beginning of significant microbial growth), the control sausages had more than 3 log CFU g^?1 and AGDF sausages much <3 log CFU g^?1. The sensory assessment pointed to some loss of textural quality, more accentuated in the AGDF sausages.