泡酒肥肉浸制过程中脂肪氧化和脂肪酸组成的变化

泡酒肥肉是豉香型白酒(玉冰烧)生产过程"陈肉酝浸"工序中的关键元素,目前对泡酒肥肉在浸制过程中的变化尚不清楚。检测了泡酒肥肉浸制过程中的各阶段肥肉的脂肪氧化及脂肪酸含量的变化。结果表明,在浸制过程中,泡酒肥肉的酸价和硫代巴比妥酸值(TBARS)显著上升(p<0.05),总饱和脂肪酸(SFA)和总不饱和脂肪酸(UFA)含量均显著下降(p<0.05)。浸制后肥肉中的棕榈酸(C_16:0)、油酸(C_18:1)、硬脂酸(C_18:0)和亚油酸(C_18:2)等脂肪酸含量较高,且变化均显著(p<0.05);总饱和脂肪酸与总不饱和脂肪酸的比值(SFA/UFA)从1.83下降到1.38,变化显著(p<0.05),说明不饱和脂肪酸的比例升高,有利于后续豉香型白酒的陈肉酝浸过程中风味物质的生成。结果表明了泡酒肥肉浸制过程中脂肪氧化及脂肪酸的变化,将为建立泡酒肥肉质量标准提供科学依据。     

Rapid determination of the fatty acid profile in pork dry-cured sausages by NIR spectroscopy

The feasibility of using near infrared reflectance spectroscopy to evaluate the generation of relevant and accurate nutritional information through a rapid determination of the fatty acid profiles in Iberian pork dry-cured sausages was analysed. Individual fatty acids contents together with the saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acid (PUFA) groups were determined in 86 samples of Iberian dry-cured sausages. NIR calibrations were developed using modified partial least squared regressions. Selected models for the estimation of major constituents (C14:0, C16:0, C16:1, C18:0, C18:1 and C18:2) exhibited coefficients of determination for cross-validation which ranged between 0.41 and 0.84 with standard errors of cross-validation (SECV) between 0.07 and 1.51. Calibrations developed for SFA, MUFA and PUFA showed coefficients of determination of 0.86, 0.53 and 0.61, and SECV values of 0.98, 1.47 and 0.88, respectively. The results obtained suggest that in general, NIR spectroscopy could provide an exceptional opportunity for the quality control of dry-cured sausages, since it allows an estimation of the major constituents and/or a classification based on their fatty acid profiles rapidly whilst avoiding the generation of chemical residues. This information could be used to estimate shelf life of products and to include extra nutritional information associated to consumers’ health in their labelling.     

ANCM bibliography

Changes in fatty acid profiles of pork loin chops fried in different culinary fats (olive oil, sunflower oil, butter and pig lard) during 10 days of refrigerated storage were studied. Olive oil-fried loin chops (OOLC) were significantly highest in monounsaturated fatty acids (MUFA) and C18:1. Sunflower oil-fried loin chops (SOLC) showed the highest polyunsaturated fatty acid (PUFA) proportions, mainly due to C18:2 contents. Butter-fried loin chops (BTLC) were significantly richer in saturated fatty acids (SFA), such as C12:0, C14:0 and C16:0, while pig lard-fried loin chops (PLLC) contained moderate proportions of SFA, MUFA and PUFA. Fatty acid profiles of neutral lipids (NL), free fatty acids (FFA) and polar lipids (PL) were slightly changed after refrigerated storage. After 10 days of refrigerated storage, differences among samples fried in different culinary fats were maintained or increased. NL from OOLC had the significantly largest percentages of C18:1 and MUFA, while SOLC had the significantly largest percentages of C18:2 and PUFA. The highest percentages of C12:0, C14:0, C16:0 and SFA were characteristic for pork loin chops fried in butter at the end of the storage period. Refrigerated pork loin chops fried in pig lard showed intermediate percentages of SFA, MUFA and PUFA. OOLC had a more desirable nutritional value than other fried pork loin chops after and before the refrigerated storage.     

猪五花肉在三种红烧工艺加工过程中的脂肪氧化规律

目的:研究红烧肉在制作过程中工艺对脂肪氧化和脂肪酸含量变化的影响。方法:以上海本帮、湖南毛氏、东北传统三种工艺红烧肉为研究对象,以其烹制过程中的不同时间(原料肉、炖煮0、30、60、90 min)为取样点,分析三种红烧肉脂肪层脂肪含量、过氧化值、硫代巴比妥酸值和脂肪酸组成的变化。结果:三种工艺红烧肉制作过程中,肥肉层脂肪含量均显著下降(p<0.05),炖煮温度越高,脂肪含量下降越显著;POV值先增大后减小,在炖煮30 min达到最大值;TBA值在炖煮过程中显著增大(p<0.05);亚油酸(C18:2)、油酸(C18:1)、棕榈酸(C16:0)以及硬脂酸(C18:0)是五花肉脂肪中的主要脂肪酸,占总脂肪酸的90%以上,亚油酸(C18:2)含量显著下降,单不饱和脂肪酸含量上升。结论:三种工艺红烧肉制作过程中,脂肪含量下降、脂肪适度氧化、脂肪酸组成改变,红烧工艺对脂肪氧化和脂肪酸含量影响较大。     

Assessment of bovine milk fatty acids using miniaturised near infrared spectrophotometer

Assessment of milk fatty acids has been proposed to support farm management practices including adjustment of feeding regimes and monitoring animal status. This study assessed the performance of a miniaturised near infrared (NIR) sensor for assessment of fatty acids in milk. Samples (n = 483) were from 114 farms, varying in lactation stages within two production seasons and included different dairy breeds. The fatty acids (C4:0, C6:0, C14:0, C16:0, C18:1 c9, SFA, MUFA, SCFA, BCFA) showed Ratio of performance to deviation values higher than two. The performance was equivalent to other independent studies utilising NIR. However, in this study, we used a low-cost NIR spectrophotometer suitable for on-the-farm use.     

Fatty acid composition of muscle and fat tissues of Omani Jebel Akhdar goats of different sexes and weights

This paper describes the fatty acid (FA) composition of muscle and fat tissue in Omani Jebel Akhdar buck, wether and does slaughtered at 11, 18 or 28 kg body weight (BW). The fat percentage in dry matter (DM) of the subcutaneous and kidney fats ranged between 85 and 98% and that of muscle ranged between 17 and 21%. Subcutaneous fat tended to have lower DM than kidney fat. Palmitic (C16:0), stearic (C18:0) and oleic (C18:1) acids comprised the largest proportions of FA in the muscle tissue (approximately 80%) with oleic acid being the most abundant. Ninety-one percent of the total FA were contributed by the C16 and C18 fatty acids being 31.6 and 58.5%, respectively. C19 and C20 were not detected in the muscle tissue. The essential FA, C20:2, C20:3 and C20:4 contributing about 1%. Muscle tissue of the Jebel Akhdar goat contained an average 51.3% and 48.7% of saturated (SFA) and unsaturated fatty acids (UFA), respectively. Polyunsaturated FA (PUFA) constituted about 5% and monounsaturated (MFA) 43.5% of the total FA. Subcutaneous fat contained more total FA (68.08%) than kidney fat (48.14%) in the whole tissue. Kidney fat contained higher percentages of C16 and C18 but less C:18:1 than subcutaneous fat. The proportions of SFA to UFA was high in both fat depots with the SFA being much higher in the kidney than subcutaneous fats. C16, C18 and C:18:1c acids comprised 64.2 and 78% and C16s and C18s made up 81 and 85% of total FA in subcutaneous and kidney fats, respectively. In both subcutaneous and kidney fats, there was a trend of increasing values of DM and fat percentage with intact males having the lowest and females the highest values. Males had higher levels of C15, C18:2 and C18:3 but lower levels of C17, C18 and total C16, C18 and C18:1 in muscle tissue. Intact males had higher levels of C10, 12, 15 FA but lower C16:1 and C16+18+18:1 than others in subcutaneous fat. Intact males had a similar trend for C12 and 14 but lower SFA and higher UFA in kidney fat. There was a trend of increasing DM and fat% in dry matter with increasing body weight. C10, 12 and 14 of the kidney fat decreased with increasing slaughter weight. There was a trend of the two C16 FA decreasing and the four C18 increasing with BW in the kidney fat. This resulted in proportions of the total C16 and C18 FA increasing from 81.8 to 86.8%. These findings confirm those of other studies on goat meat quality that, as judged by fatty acid composition it is not inferior to that of meats from other farm animals.     

烹调方式对猪肉肌内脂肪中脂肪酸组成的影响

不同的烹调方式使猪肉中的脂肪含量和脂肪酸组成发生变化。以猪背最长肌为原料,通过4种常见的烹调方式:蒸、煮、微波、烤,探究脂肪酸的变化规律,进而指导人们的烹调方式。采用改进的Folch法提取烹调后猪肉中的脂肪,用氨丙基硅胶固相萃取小柱分离脂肪中的甘油三酯和磷脂,并采用气相色谱,以十三烷酸甲酯为内标定量分析总脂、甘油三酯及磷脂的脂肪酸组成。结果表明,与对照组相比,蒸、微波、煮和烤对猪肉脂肪中甘油三酯的脂肪酸组成无显著影响。而微波、煮和烤均使磷脂的脂肪酸组成发生显著性变化,其中饱和脂肪酸(SFA)和反式脂肪酸(TFA)的含量均显著增加,而单不饱和脂肪酸(MUFA)与多不饱和脂肪酸(PUFA)的含量明显减少,变化最明显的为烤制;蒸制对磷脂的脂肪酸组成影响最小,仅SFA和PUFA发生一定程度的变化;总脂肪酸组成差异显著,其含量变化主要是由磷脂的变化引起的。结论:烹调对磷脂影响显著;蒸制对猪肉脂肪的脂肪酸保护效果最好,烤制易破坏脂肪酸,从而降低营养价值。     

GC-MS法测定宣威火腿中脂肪酸组成

以宣威火腿为对象,通过提取成熟宣威火腿的肌间脂肪和皮下脂肪,采用气相色谱-质谱联用法(GC-MS)对宣威火腿肌间脂肪与皮下脂肪中脂肪酸的组分进行探讨。结果表明:宣威火腿肌间脂肪中含11种饱和脂肪酸,占总脂肪酸的34.75%,15种不饱和脂肪酸,占总脂肪酸含量的64.78%,主要的脂肪酸为油酸(C18∶1)、棕榈酸(C16∶0)、硬脂酸(C18∶0)、亚油酸(C18∶2),含量分别为33.44%、23.37%、8.44%、20.55%;皮下脂肪中含11种饱和脂肪酸,占总脂肪酸的36.23%,15种不饱和脂肪酸,占总脂肪酸含量的63.47%,主要的脂肪酸为油酸(C18∶1)、棕榈酸(C16∶0)、硬脂酸(Cl8∶0)、亚油酸(C18∶2),含量分别为31.47%、21.90%、11.13%、22.39%。     

青花鸡、茶花鸡2号和白羽肉鸡肌肉脂肪酸含量比较分析

为研究青花鸡、茶花鸡2号和白羽肉鸡3种鸡肌肉中脂肪酸含量差异,先采用氯仿-甲醇法对鸡肉粉进行脂肪提取,并对脂肪提取物进行甲酯化处理,再应用高效气相色谱仪检测3种鸡肌肉中的18种脂肪酸.结果表明:3种鸡肌肉脂肪酸均以棕榈酸(C16∶0)、硬脂酸(C18∶0)、油酸(C18∶1 n-9c)和亚油酸(C18∶2 n-6c)为...     

The influences of carcass weight and depot on the fatty acid composition of fats of suckling Manchego lambs

The effects of carcass weight (<5.5 kg, 5.5–6.5 kg, ⩾6.5 kg) of Manchego suckling lambs, type of fat depot of the leg (subcutaneous, intermuscular and intramuscular) and muscle (m. longissimus dorsi (LD) or m. quadriceps femoris (QF)) on the fatty acid composition were studied. Carcass fatness increased with increasing carcass weight. However, few differences in fatty acid proportion were observed between the three carcass weight groups. The lightest carcasses had lower proportions of myristic (C14:0) and palmitoleic (C16:1) acid and higher proportions of stearic (C18:0) acid, desirable fatty acids (DFA) (C18:0 + total unsaturated fatty acid (TUFA)) and a greater nutritive value ((C18:0 + C18:1)/C16:0). The fatty acid composition of subcutaneous and intermuscular fat depots of the leg were similar, whereas the intramuscular fat depot was different from both of these, since it had a lower proportion of saturated fatty acids (SFA), a greater proportion of TUFA, higher PUFA/SFA and n − 6/n − 3 ratios, and greater DFA and nutritive values. The intramuscular fat of the LD was more saturated than QF, higher SFA, and had lower value of PUFA/SFA ratio and DFA. These results indicated that the intramuscular fat quality of the leg was better than subcutaneous and intermuscular fat depots and also that intramuscular fat displayed better attributes of quality (lower SFA, higher TUFA, and greater PUFA/SFA ratio and DFA as well) than intramuscular fat of the LD from the consumer health standpoint. Despite carcass weight affected carcass fatness, it did not seem to influence the proportions of saturated or polyunsaturated fatty acids. For this reason, carcass weight probably had little effect on the organoleptic characteristics of the meat.     

Influences of anatomical location and muscle quality on porcine lipid composition

Carcasses of sixty Lacombe and Lacombe cross swine fed the same high concentrate ration were selected to equally represent three muscle quality groups (pale soft exudative (PSE), normal and dark firm dry (DFD)). These carcasses were utilised to supply back and belly fat samples for the evaluation of the influences of muscle quality and anatomical location on fatty acid composition. Back fat samples had lower percentages of palmitic (C16:0) and stearic (C18:0) acids, long (≥ C18), and short (≤ C16) chain saturated fatty acids and total saturated fatty acids and higher percentages of oleic (C18:1) and linoleic (C18:2) acids, polyunsaturated fatty acids and total unsaturated fatty acids than belly fat samples. They also had a higher unsaturated fatty acid to saturated fatty acid ratio than belly fat samples. Carcasses with DFD hams and loins had lower percentages of palmitoleic (C16:1) and linoleic (C18:2) acids and polyunsaturated fatty acids in their back fat than those with PSE hams and loins. They also had higher (P < 0·05) percentages of myristic (C14: 0) and stearic (C18:0) acids and long chain saturated fatty acids (≥ C18) and lower percentages (P < 0·05) of palmitic (C16:0) and palmitoleic (C16:1) acids in their back fat than carcasses with normal hams and loins. Moreover, they had lower (P < 0·05) percentages of palmitoleic (C16:1) and linoleic (C18:2) acids and poly-unsaturated fatty acids in their belly fat than carcasses with normal and PSE hams and loins. The fact that the lipid composition of carcasses differed significantly among muscle quality groups is of considerable importance, since it implies that factors (stress) producing differences in muscle quality may also significantly influence the fatty acid composition-and thereby the physical properties of carcass lipids.     

青海八眉猪与甘肃黑猪肉品质及营养成分比较

通过分析比较青海八眉猪和甘肃黑猪肉质性状、营养成分、氨基酸、脂肪酸、肌苷酸等含量差异,为研究青海八眉猪肉提供数据支撑,并为其资源保护提供一定依据。以10头青海八眉猪和10头甘肃黑猪为研究对象,采用国标法对其背最长肌的各个指标进行了系统比较分析。结果表明:八眉猪肉的失水率、熟肉率显著高于甘肃黑猪肉(P<0.05),大理石纹、肉色、脂肪色、pH在2个品种肉质上差异不显著(P>0.05);八眉猪肌肉中粗脂肪含量显著低于甘肃黑猪(P<0.05),蛋白、水分含量显著高于甘肃黑猪(P<0.05),粗灰分含量差异不显著。相对于甘肃黑猪肌肉中的7种脂肪酸,青海八眉猪肌肉含有14种脂肪酸,且饱和脂肪酸和多不饱和脂肪酸含量显著高于甘肃黑猪(P<0.05),不饱和脂肪酸及单不饱和脂肪酸显著低于甘肃黑猪(P<0.05);甘肃黑猪肌肉氨基酸总量(20.23 g/100 g)高于青海八眉猪(19.14 g/100 g),八眉猪肌肉鲜味氨基酸含量(8.76 g/100 g)高于甘肃黑猪(7.84 g/100 g)。八眉猪肌肉肌苷酸含量为2.44 mg/g,显著高于甘肃黑猪肌肉肌苷酸含量2.05 mg/g(P<0.05);八眉猪肌肉肌酐、次黄嘌呤含量依次为0.55、0.13 mg/g,均显著低于甘肃黑猪的0.81、0.55 mg/g(P<0.05)。由此说明,相比于甘肃黑猪,青海八眉猪肌肉氨基酸比例更合理,脂肪酸更丰富,肌苷酸含量更高,高蛋白、低脂肪,肉质更鲜美。     

猪肉肌间/脂肪组织在蒸煮过程中的脂肪酸组成变化

猪肉作为人体的一种主要、普遍的动物性油脂来源,其脂肪酸组成在烹饪过程中的变化,尤其是饱和脂肪酸、单不饱和脂肪酸和多不饱和脂肪酸比例的变化,对人体健康有着重要的影响。本实验通过对猪背膘、猪通脊和腊（猪）肉肥肉进行不同时间的蒸煮,采用气相色谱法对其中的各种脂肪酸进行分析,探索脂肪酸营养构成较好的蒸煮时间。结果表明：猪背膘在蒸煮过程中各脂肪酸组成比例变化不明显,在4.0 h时3 种脂肪酸比例较好,为3.6∶4.9∶1.0。其中亚油酸和亚麻酸的含量均在4.0 h时达到最大值。猪通脊在蒸煮过程中变化明显,在1 h时3 种脂肪酸比例较好,为2.5∶2.6∶1.0。腊肉肥肉在蒸煮过程中变化很明显,在2 h时是一个明显的转折点,3 种脂肪酸的比例最好,为1.7∶2.9∶1.0。     

PRODUCTION OF LOW-FAT FRANKFURTERS WITH VEGETABLE OILS FOLLOWING THE DIETARY GUIDELINES FOR FATTY ACIDS

Low-fat frankfurters (10% fat) were produced with vegetable oils following the dietary guidelines for fatty acids as suggested in the currently recommended diet (CRD) by the American Heart Association, the Grundy diet (GD) and the Mediterranean diet (MD). MD-frankfurters, produced with olive oil (31.82%) and soybean oil (17.51%), had the highest (P<0.05) ratio of monousaturated fatty acids (MUFA)/saturated fatty acids (SFA) minus stearic. CRD-frankfurters, produced mainly with cottonseed oil (40.70%) and soybean oil (6.90%), had the highest (P<0.05) content of polyunsaturated fatty acids (PUFA). GD-frankfurters, produced with cottonseed oil (34.04%) and olive oil (15.19%), had the highest (P<0.05) ratio of (C18:2 n-6)/(C18:3 n-3). Compared to high-fat frankfurters (27% all animal fat), low-fat frankfurters had lower (P<0.05) stearic acid and trans ω-9 oleic acid, higher (P<0.05) content of total PUFA, higher (P<0.05) ratio of (C18:2+C 18:3)/SFA minus stearic acid, and lower cholesterol content (52.60%-59.11%), were darker, redder and more yellow, firmer and less juicy, but had similar overall acceptabily.     

Genetic determination of fatty acid composition in Spanish Churra sheep milk

The objective of this study was to estimate the genetic variation of ovine milk fatty acid (FA) composition. We collected 4,100 milk samples in 14 herds from 976 Churra ewes sired mostly by 15 AI rams and analyzed them by gas-liquid chromatography for milk fatty acid composition. The studied traits were 12 individual FA contents (proportion in relation to the total amount of FA), 3 groups of fatty acids [saturated fatty acids (SFA), monounsaturated FA (MUFA), and polyunsaturated FA (PUFA)], and 2 FA ratios (n-6:n-3 and C18:2 cis-9,trans-11:C18:1 trans-11). In addition, percentages of fat and protein and daily milk yield were studied. For the analysis, repeatability animal models were implemented using Bayesian methods. In an initial step, univariate methods were conducted to test the hypothesis of the traits showing additive genetic determination. Deviance information criterion and Bayes factor were employed as model choice criteria. All the studied SFA showed additive genetic variance, but the estimated heritabilities were low. Among unsaturated FA (UFA), only C18:1 trans-11 and C18:2 cis-9,cis-12 showed additive genetic variation, their estimated heritabilities being [marginal posterior mean (marginal posterior SD)] 0.02(0.01) and 0.11(0.04), respectively. For the FA groups, only PUFA showed significant additive genetic variation. None of the studied ratios of FA showed additive genetic variation. In second multitrait analyses, genetic correlations between individual FA and production traits, and between groups of FA and ratios of FA and production traits, were investigated. Positive genetic correlations were estimated among medium-chain SFA, ranging from 0 to 0.85, but this parameter was close to zero between long-chain SFA (C16:0 and C18:0). Between long- and medium-chain SFA, estimated genetic correlations were negative, around −0.6. Among those UFA showing significant additive genetic variance, genetic correlations were close to zero. The estimated genetic correlations among all the investigated FA, milk yield, and fat and protein percentages were not different from zero. Our results suggest that low additive genetic variation is involved in the determination of the FA composition of milk fat in Churra sheep under current production conditions, which results in low values of heritabilities.     

蒙古斑点马不同部位脂肪和肌肉组织中脂肪酸组成的比较研究

通过对蒙古斑点马不同部位脂肪和肌肉组织中脂肪酸组成进行分析比较,旨在明确蒙古斑点马体脂脂肪酸组成特点。选择3 匹成年蒙古斑点马,屠宰后采集肾周、肠周和皮下脂肪以及肩肌、背最长肌和臀肌样品,利用气相色谱法测定脂肪酸组成及含量。结果表明：蒙古斑点马不同脂肪组织中均检出19 种脂肪酸,其中饱和脂肪酸（saturated fatty acid,SFA）含量34.77%～37.38%,不饱和脂肪酸（unsaturated fatty acid,UFA）含量达60%以上,UFA中单不饱和脂肪酸（monounsaturated fatty acid,MUFA）含量33.04%～36.39%,多不饱和脂肪酸（polyunsaturated fatty acid,PUFA）含量26.47%～27.51%,其中皮下脂肪C10:0、C18:0、C20:0含量显著低于肾周和肠周脂肪（P＜0.05）;MUFA在皮下脂肪的沉积程度较其他2 个部位高,但均无统计学差异;PUFA中C18:3 n-3含量最高,其在各脂肪组织间无显著差异。3 个不同部位肌肉中均检出15 种脂肪酸,其中SFA含量占总脂肪酸含量的38.32%～40.04%,MUFA含量占35.70%～40.19%,PUFA含量占15.25%～20.33%;SFA中背最长肌和臀肌C12:0含量显著高于肩肌（P＜0.05）,其余SFA在不同部位肌肉间无显著差异;MUFA中背最长肌C16:1含量显著高于肩肌和臀肌（P＜0.05）;肩肌n-6/n-3 PUFA比值显著高于背最长肌和臀肌（P＜0.05）;皮下脂肪的C18:3 n-3和总PUFA含量显著高于背最长肌（P＜0.05）。综上所述,蒙古斑点马不同部位脂肪和肌肉组织脂肪酸组成各具特点,但UFA含量均较高。     

The value of different fat supplements as sources of digestible energy for lactating dairy cows

The effects of fat supplements that differed in fatty acid composition (chain length and degree of saturation) and chemical form (free fatty acids, Ca salts of fatty acids, and triacylglyceride) on digestible energy (DE) concentration of the diet and DE intake by lactating cows were measured. Holstein cows were fed a control diet [2.9% of dry matter (DM) as long-chain fatty acids] or 1 of 3 diets with 3% added fatty acids (that mainly replaced starch). The 3 fat supplements were (1) mostly saturated (C18:0) free fatty acids (SFA), (2) Ca-salts of fatty acids (CaFA), and (3) triacylglyceride high in C16:0 fatty acids (TAG). Cows fed CaFA (22.8 kg/d) consumed less DM than cows fed the control (23.6 kg/d) and TAG (23.8 kg/d) diets but similar to cows fed SFA (23.2 kg/d). Cows fed fat produced more fat-corrected milk than cows fed the control diet (38.2 vs. 41.1 kg/d), mostly because of increased milk fat percentage. No differences in yields of milk or milk components were observed among the fat-supplemented diets. Digestibility of DM, energy, carbohydrate fractions, and protein did not differ between diets. Digestibility of long-chain fatty acids was greatest for the CaFA diet (76.3%), intermediate for the control and SFA diets (70.3%), and least for the TAG diet (63.3%). Fat-supplemented diets had more DE (2.93 Mcal/kg) than the control diet (2.83 Mcal/kg), and DE intake by cows fed supplemented diets was 1.6 Mcal/d greater than by cows fed the control, but no differences were observed among the supplements. Because the inclusion rate of supplemental fats is typically low, large differences in fatty acid digestibility may not translate into altered DE intake because of small differences in DM intake or digestibility of other nutrients.     

Lipid composition of Australian pork cuts 2005/2006

A study of the cholesterol content and fatty acid composition of fresh retail Australian pork was undertaken to determine whether new breeding, feeding and processing methods had resulted in any compositional changes in fresh pork in the market place since surveys undertaken in previous decades. Samples of 13 popular pork cuts were purchased from randomly selected supermarkets and butchers’ stores in urban areas across the socioeconomic scale in three States of Australia, and analysed, separable fat and separable lean, in late 2005 and early 2006. Variability was low across States for saturated and monounsaturated fatty acids, but more pronounced for polyunsaturated acids. The separable lean portions of all pork cuts contained levels of n-3 fatty acids and conjugated linoleic acid (C18:1c9t11) in measurable but not nutritionally claimable amounts, whilst total trans fatty acid levels were very low. There appeared to be some differences in fatty acid composition across States that may have resulted from feeding method. Cholesterol contents were similar to levels in the 80s and 90s for separable lean pork tissue, but presently are lower for separable fat tissue than for separable lean.     

Fatty acid composition of adipose depots of suckling lambs raised under different production systems

Forty-nine male Talaverana-breed suckling lambs slaughtered at 14 kg live weight were used to study the fatty acid composition of adipose depots of lambs raised under different management systems (pasture or drylot) and diets (maternal milk with or without a concentrate supplement). Drylot lambs displayed a higher fatness score, in addition to greater dorsal fat thickness; these parameters corresponded with a greater percentage of total fat at dissection. Addition of concentrate to the diet did not modify carcass fatness. Drylot lambs presented higher proportions of oleic acid (C18:1) and monounsaturated fatty acids (MUFA) and lower linolenic acid (C18:3) values in subcutaneous and intramuscular fat (muscle longissimus thoracis). The subcutaneous fat of these lambs thus displayed a higher n-6/n-3 PUFA ratio (C18:2/C18:3) than that of pasture-raised ones. Concentrate in the diet of both pasture and drylot lambs resulted in higher linoleic fatty acid (C18:2) and PUFA values and a greater PUFA/SFA ratio in intramuscular fat than the corresponding values of lambs which consumed maternal milk alone. Loin displayed a higher percentage of subcutaneous and intramuscular chemical fat than leg. Compared with intramuscular leg fat (muscle quadriceps femoris), intramuscular loin fat (muscle longissimus thoracis) had lower oleic acid (C18:1) and MUFA values, higher PUFA values and a higher PUFA/SFA ratio, due to greater linolenic acid (C18:3) levels.     

Cooking effect on fatty acid profile of pork breakfast sausages enriched in conjugated linoleic acid by dietary supplementation or direct addition

The effectiveness of increasing CLA in pork products through animal dietary supplementation or direct addition in the product formulation has been studied, and the effect of grilling on dry matter and fat contents and fatty acid composition has been analysed. Sausages made with meat and back fat from pigs with CLA dietary supplementation had the highest saturated fatty acid content. Sausages from dietary supplementation and direct addition had CLA levels between 6% and 7% of total fatty acids. Moisture and fat contents decreased and increased respectively after cooking for the three sausage types (control, dietary supplementation, direct addition). Grilling had little effect on fatty acid levels, especially for sausages with direct addition in the product formulation. In general, saturated fatty acids increased and poly-unsaturated fatty acids decreased due to the increase of C16:0 and to the decrease of C18:2 n − 6c and C18:3 n − 3 fatty acids. Added CLA, both from animal dietary supplementation or direct addition, remained at similar levels in cooked sausages to those found in raw sausages.