Prevalence and relationships of sensory taint, 5α-androstenone and skatole in fat and lean tissue from the loin (Longissimus dorsi) of barrows, gilts, sows, and boars from selected abattoirs in the United States

This study assessed prevalence of boar taint in backfat and lean of barrows, gilts, sows, and boars, collected from abattoirs, without knowledge of the farms of origin, in different regions in the United States. Concentrations of 5α-androstenone (liquid chromatography/mass spectroscopy) and skatole (liquid chromatography with fluorescent detection) in backfat were measured. A trained panel evaluated boar taint aroma in heated samples. Mean 5α-androstenone and skatole levels were low among barrows, gilts, and sows, whereas 55.8% of boars scored above a 1.0 μg/g threshold for 5α-androstenone concentrations and 34.2% were above a 0.2 μg/g threshold for skatole concentrations. Mean aroma scores for backfat and lean from barrows, gilts, and sows were low. In comparison, 59.2% of boars had elevated mean aroma scores from fat samples and 31.7% from lean. Importantly, boar taint aroma was detectable by the trained panel in at least some animals in each of the sex classes.     

Comparison of Duroc and British landrace pigs for meat a and eating quality

Duroc and halothane negative British Landrace boars and gilts were performance tested from 30 to 80kg on ad-libitum or restricted feeding regimes, with like-sexed non-littermate groups of pigs penned together. Meat and eating quality was determined using objective laboratory measurements and by taste panel and consumer panel assessment on 160 pigs with 20 full-sib families for each breed, and two boars and two gilts per family. Duroc M. longissimus(?) was darker in colour, had a more intense, redder colour and contained more fat and less moisture than Landrace muscle. Duroc subcutaneous fat was less firm, had a higher water content and concentrations of linoleic acid and lower concentrations of stearic acid than Landrace fat. The taste and consumer panels scored Duroc meat as being more juicy, but less tender, having poorer flavour and being less acceptable than Landrace meat. The higher juiciness scores of Duroc meat were probably attributable to the higher intramuscular fat content compared to Landrace meat. Duroc boars had lower values for flavour liking and acceptability compared to other breed-sex combinations which may be due to the particular fatty acid composition of the subcutaneous fat in Duroc boars.     

Fatty acid composition of backfat in large white pigs selected for low backfat thickness

Samples of midback fat were taken from 157 Large White boars and analysed for fatty acid composition and melting point of lipid. Seventy-seven boars were from a line showing fast efficient growth and low backfat depth (selection line) and 80 from a random-mated control line. All were performance-tested from 27 to 87 kg liveweight on ad libitum feeding.

Selection line pigs required 6 % less feed per kilogramme liveweight gain and had thinner backfat at each point of measurement (16–27 %) than the controls but there was no line difference in daily liveweight gain. Selection line pigs had ‘eye muscles’ which were slightly paler and had a greater drip loss than the controls.

The fatty acid composition and melting point of the lipid extracted from backfat was similar between the lines except that the concentration of linoleic acid (C18:2) in both inner and outer layers was some 14% higher in the selection line. There were significant negative correlations between the concentration of C18:2 and the various backfat measurements. Positive correlations were found between some backfat measurements and the concentration of stearic acid (C18:0), particularly in the selection line.

Variation in melting point in both layers was more strongly related to variation in the concentration of C18:0 than to that of any other fatty acid.     

Effect of incorporation of dietary polyunsaturated fatty acids in pork backfat on the quality of salami

The suitability of backfat high in polyunsaturated fatty acids (PUFA) for salami manufacture was assessed. Eighty pigs (barrows and gilts) were fed four diets, containing 21, 25, 28 and 28 g PUFA/kg feed, originating mainly from soybeans and/or soybean oil in the first three diets and from linseed in the fourth. Salami was prepared with backfat from these pigs, according to gender and dietary treatment. Samples were taken throughout the ripening. The taste panel rejected the two high PUFA (diet 3 and 4) levels; moreover fishy off-flavours were detected for dietary treatment four. Twenty-five grams PUFA/kg feed, corresponding with 23% PUFA in backfat or 15% PUFA in salami, results in acceptable taste, if linoleic acid is the predominant PUFA. However, all PUFA levels resulted in salamis too soft to be commercialized, as evidenced by a fatty film on the salami slicing machine.     

The composition and consistency of pig backfat as it affects the quality of vacuum-packed rindless bacon rashers

Samples of adipose tissue from unsatisfactory, soft, vacuum-packs of rindless bacon rashers were compared with satisfactory harder samples to determine the factors responsible for the difference in consistency. Lipid from unsatisfactory packs contained significantly higher mean concentrations of unsaturated fatty acids, lower mean concentrations of saturated fatty acids and had a lower mean melting point and mean slip point. Discriminant analysis revealed that the samples were best differentiated according to their proportion of linoleic acid or by the ratio of stearic acid to linoleic acid. Linoleic acid was the best discriminator although stearic acid and palmitic acid were correlated best with the melting point and slip point of the lipid and with the force required to puncture the intact adipose tissue by a probe attached to an Instron materials testing machine. Samples which would give satisfactory firm packs, based on the data from discriminant analysis, required a puncture force greater than 7N. In terms of the spectrum of backfat consistency in British pigs, satisfactory bacon comes from hard backfat whereas the unsatisfactory packs come from backfat of medium consistency.     

Incorporation of dietary polyunsaturated fatty acids in pork tissues and its implications for the quality of the end products

One hundred and ten fattening pigs of a Piétrain × Hybrid cross-barrows and gilts in equal numbers-were distributed over five feeding formulas, containing increasing amounts of polyunsaturated fatty acids (PUFA), in the form of rapeseed. The aim of the study was to evaluate the maximum admissible amount of PUFA in the pig diet before problems-in terms of backfat consistency and storage stability-occur and to investigate the incorporation of dietary PUFA in intramuscular fat as well. A tendency towards reduced feed (energy) intake was obvious from the 7% rapeseed inclusion level, apparently resulting in a somewhat thinner backfat layer. None of the backfat samples showed a visible yellow discolouration instead thin backfat layers appeared as pink. Backfat consistency was lower for gilts and decreased with increasing dietary PUFA levels. PUFAs in the feed and in backfat were very well correlated (0.8-0.9) as expected; correction for de novo fat synthesis (by means of backfat thickness) did not alter the correlations within one sex group. Thresholds for PUFA in feed-15 g PUFA/kg feed-and for PUFA in back-fat-iodine value of 70 or 15% PUFA-were all surpassed in this experiment: 18 g PUFA/ kg feed resulted in maximally 22% PUFA in the outer backfat layer. The backfat PUFA limit was reached at relatively low feed PUFA levels. This might be explained by thin and hence more unsaturated backfat layers in lean or underweight pigs. Oxidative stability of the backfat after storage for 1 year in the freezer was satisfactory. The total intramuscular fat (IMF) content showed no obvious relationship with diet, in contrast with sex: barrows had more IMF than gilts. IMF consisted in 80% apolar phase and 20% polar fraction. The apolar fraction showed similar feed and sex tendencies as backfat, although correlations between feed and apolar fraction PUFAs were higher for gilts than for barrows. The amount of phospholipid was invariable throughout all treatments. Only linoleic acid-the major fatty acid-showed some feed and sex influence. In view ofthf results obtained the threshold for feed and backfat PUFA can be as high as, respectively, 18 g PUFA/kg feed and 22% PUFA in backfat, without deterioration of fresh and frozen backfat. However, for meat processing, demands could be more severe.     

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.     

Effect of crossbreeding and gender on meat quality and fatty acid composition in pork

This study considers the effect of crossbreeding and gender (barrows; gilts) on meat quality and intramuscular and subcutaneous fatty acid composition in pork. The sire lines included Large White (LW), Duroc (D) and Pietrain (P) and the dam line was Landrace (LR)×LW, producing LW×(LR×LW), D×(LR×LW) and P×(LR×LW). Pork samples were removed from Longissimus dorsi (LD) and Semimembranosus (SM) muscles and subcutaneous fat (SCF). There were no important differences in meat quality parameters but D×(LR×LW) had the highest percentage of intramuscular fat. Castrated males had more intramuscular fat and more intense meat colour than female pigs. The Large White and Duroc sire line had saturated fatty acids (SFA) in SM, whereas the Pietrain sire line was significantly higher than Duroc sire line in the concentration of polyunsaturated fatty acids (PUFA), PUFA/SFA (P/S) and the n-6/n-3 ratio. The concentrations of SFA and monounsaturated fatty acids (MUFA) in SCF were significantly higher in LW×(LR×LW) and P×(LR×LW), respectively. No differences were found in the percentage of PUFA, P/S and n-6/n-3 ratio between D×(LR×LW) and P×(LR×LW). Female pigs had the most polyunsaturated intramuscular and subcutaneous fat. The results demonstrate small differences in fatty acid compositions among sires.     

Effect of Age, Sex and Strain on the Fatty Acid Composition of Goose Muscle and Depot Fats

The fatty acid composition of muscle and depot fats from four strains of geese was determined by GLC analysis. Differences due to sex and age of goose were not significant (P < 0.01). The major fatty acids of depot fat were oleic (54%), palmitic (22%), linoleic (11%) and stearic (8%). Muscle contained from 4.7–9.6% fat composed mainly of oleic (42%), palmitic (25%), linoleic (14%) and stearic (12%) acids. The muscle fat content of Pilgrim and Hungarian geese was less than that of the Crossbred (P < 0.01) and of the Chinese strain.     

Effect of sex and terminal sire genotype on performance, carcass characteristics, and meat quality of pigs slaughtered at 117 kg body weight

The effects of gender (barrows; gilts) and terminal sire genotype (DD, Danish Duroc; PxLW, Pietrain×Large White) on performance and carcass and meat quality of pigs sacrificed at a fixed weight of 117 kg were studied. Barrows ate more feed, grew faster, and had poorer feed conversion and less yield of trimmed lean cuts than gilts. Castrates were fatter and had more intramuscular fat and more intense colour of the meat than females. Crossbreds from DD boars grew faster and had better feed conversion than crossbred from P×LW boars. Also, DD sired-pigs had smaller dressing percentages but more trimmed lean cuts proportion than P×LW sired-pigs. Meat from DD pigs was more tender, had more intramuscular fat, and presented lower a* value than meat from P×LW pigs. We conclude that DD boars are a good alternative to P×LW boars for production of heavy pigs destined for the dry-cured industry.     

花生籽粒发芽过程中脂肪代谢的变化

为探究花生籽粒在萌发过程中脂肪代谢的规律,对花育30号花生籽粒在黑暗条件下30℃恒温发芽72 h,每隔12 h取样,分析其粗脂肪含量、脂肪酸组成、脂肪酶活力、脂氧合酶(lipoxygenase,LOX)和过氧化物酶(peroxidase,POD)活力、过氧化物值(peroxide value,POV)、羰基价(carbonyl group value,CGV)。结果表明:花生籽粒中脂肪酸主要有棕榈酸、硬脂酸、油酸、亚油酸、花生酸、花生烯酸、山芥酸和木蜡酸。与未发芽花生籽粒相比,花生籽粒在发芽过程中粗脂肪含量显著降低(P0.05);饱和脂肪酸总量在发芽36 h后显著下降(P0.05),其中棕榈酸含量先降低后无显著变化,硬脂酸含量显著下降(P0.05),木蜡酸含量显著上升(P0.05);不饱和脂肪酸含量在籽粒发芽过程中先降低后显著上升(P0.05),其中油酸和花生酸含量显著上升(P0.05),亚油酸含量显著降低(P0.05)。花生籽粒脂肪酶活力在发芽过程中先显著上升后显著下降;LOX活力在36 h达到最大值,48 h后活力显著下降;POD活力在发芽48 h达到最大值,此后变化不显著。POV和CGV在发芽过程中均呈现先显著上升,60 h后显著下降趋势(P0.05)。相关性分析表明,亚油酸含量的变化与棕榈酸、硬脂酸正相关,与油酸、山芥酸、木蜡酸负相关;油酸含量变化与花生烯酸、木蜡酸正相关,与棕榈酸、硬脂酸、亚油酸、花生酸负相关;粗脂肪含量变化与脂肪酶活性、POV、CGV、POD活性负相关,而脂肪酶活性与POV、CGV、POD活性正相关。     

Effects of growth rate, sex and slaughter weight on fat characteristics of pork bellies

A total of 119 Duroc × (Landrace × Yorkshire) commercial pigs were used to investigate the effect of growth rate (fast vs slow), sex (barrows vs gilts) and slaughter liveweight (107, 115 and 125 kg) on the fat characteristics of bellies. Backfat thickness increased with weight (P < 0.01). Fat firmness score was only affected by sex (P < 0.05), with gilts showing softer bellies than barrows. Fat from gilts and slow growing pigs showed a lower proportion of saturated fatty acids (SFA; P < 0.001 and P < 0.01, respectively), a higher proportion of linoleic fatty acid (C18:2 n-6; P < 0.01), a higher proportion of total polyunsaturated fatty acids (PUFA; P < 0.001 and P < 0.01, respectively), and an increased iodine value (P < 0.001). Consequently, the fat from these bellies had higher PUFA:SFA ratios (P < 0.001) and n-6:n-3 ratios (P < 0.01 and P < 0.001, respectively) than that from the bellies of barrows and fast growing pigs. The belly fat from barrows and fast growing pigs had higher stearic fatty acid (C18:0; P < 0.01) and SFA proportions (P < 0.001 and P < 0.01, respectively) than that from gilts and slow growing pigs. The belly fat from gilts and slow growing pigs would better meet the health requirements of consumers, but it is more prone to rancidity during storage leading to a potentially reduced bacon shelf-life.     

Effect of different fatty acids on the proliferation and cytokine production of dairy cow peripheral blood mononuclear cells

During the transition period, dairy cows often experience negative energy balance, which induces metabolic and immunological disturbances. Our previous work has shown a relationship between the inhibition of immune functions and increased blood nonesterified fatty acid (NEFA) levels. In this study, we evaluated the effect of 11 fatty acids (palmitoleic, myristic, palmitic, stearic, oleic, linoleic, docosahexaenoic, conjugated linoleic, lauric, eicosapentaenoic, and linolenic acids) as well as a mix that represented the NEFA profile observed during the transition period at different concentrations (0, 50, 100, and 250 µM) on proliferation and cytokines secretion of lymphocytes. To assess lymphoproliferation, peripheral blood mononuclear cell (PBMC) from 5 healthy cows (166–189 d in milk) were isolated, stimulated with the mitogenic lectin concanavalin A (ConA), incubated for 72 h with or without fatty acids, and subjected to flow cytometry analysis. Our results showed that all fatty acids, except lauric acid, significantly reduced proliferation of PBMC in a dose-dependent manner. The most detrimental effect was observed with conjugated linoleic and stearic acids, where proliferation of PBMC was already inhibited at the lowest dose (50 µM). For cytokine secretion, we found that levels of IL-4 in culture supernatant of ConA-stimulated PBMC were reduced after a 24-h exposure to the lowest dose (50 µM) of oleic and palmitoleic acids. A dose of 100 µM of eicosapentaenoic acid, NEFA mixture, and myristic acid was necessary to observe a reduction in IL-4 levels. The PBMC also showed a decrease in the secretion of IFN-γ in response to lauric, linolenic, palmitoleic, and stearic acids at 50 µM and myristic acid at 100 µM. Overall, polyunsaturated fatty acids were more potent inhibitors of cytokine secretions than saturated fatty acids. In addition, we detected an inverse relationship between the melting points of fatty acids and their ability to inhibit IL-4 and IFN-γ secretions, as evidenced by greater inhibition with low–melting point fatty acids. Overall, our study confirmed that NEFA have a negative effect on some lymphocyte functions, and that their inhibitory effect on cytokine secretions increases with the degree of unsaturation.     

不同产地苦杏仁油的含量及成分分析

通过对庆阳,隰县,安塞,镇原,华池,灵台,方山以及麟游的苦杏仁含油率、脂肪酸组成以及VE含量的比较研究,结果表明:不同产地的苦杏仁含油率在42.642%到53.569%之间,各产地的苦杏仁油脂肪酸组成相同,都含有6种脂肪酸,即亚油酸、油酸、棕榈酸、硬脂酸、棕榈油酸以及亚麻酸.苦杏仁油中的总VE含量在19.4 mg/100 g到55.833 mg/100 g之间,不同产地苦杏仁油中不饱和脂肪酸质量分数均在94%以上,其中油酸质量分数在62.8%以上,亚油酸质量分数在24%以上.综合考虑含油率、不饱和脂肪酸以及VE含量优选出黄土高原地区苦杏仁的最佳产地为麟游,该结果为苦杏仁产业化的发展以及生产基地建设提供了科学的依据.     

Evaluation of pork backfat firmness and lard consistency using several different physicochemical methods

A total of 96 pigs were fed on a control diet (barley, wheat, soybean meal) or the control diet supplemented with one of six fats, differing in saturated (SFA), cis‐ and trans‐monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) content, in order to produce backfat widely differing in fatty acid composition. In addition to fatty acid composition, firmness was measured, by means of a puncture test, in the intact outer backfat layer and in lard extracted from the outer layer. Melting behaviour and solid fat content (SFC) were determined by differential scanning calorimetry and crystallisation time with a Rapid Interesterification Control‐Box. Regression analyses revealed that all consistency traits were mainly dependant on SFA content, particularly stearic acid. Cis‐MUFA were the next most decisive for crystallisation time and SFC. The prediction of firmness and SFC at 0 °C was improved when the proportion of PUFA was also considered. The stearic to linoleic acid ratio provided the best prediction of lard firmness. It was concluded that MUFA and PUFA exert specific effects on the different consistency characteristics and not only PUFA but also MUFA should be considered in feeding recommendations for growing‐finishing pigs when lard consistency is to be improved. Copyright © 2004 Society of Chemical Industry     

Lipid in Ripening Banana Fruit

SUMMARY: Lipid extracts were isolated from unripe and ripe banana pulp and peel and the fatty acid composition of the extracts was determined. Unsaturated acids, particularly linoleic and palmitoleic, decreased about 3-fold in the pulp while more than a 2-fold increase in stearic acid occurred. In general, unsaturated fatty acids decreased in both the pulp and peel during ripening. The peel contained almost 4 times more lipid than the pulp.     

Total lipid content, fatty acids and 4-desmethylsterols accumulation in developing fruit of Pistacia lentiscus L. growing wild in Tunisia

This research has determined oil, fatty acid and sterol contents of the Tunisian Pistacialentiscus (Lentisc) fruits during maturation. Low oil accumulation was observed during the first 35 days after the fruiting (DAF) date (from 1.83% to 2.57%). After that, two phases were distinguished (35th until the 60th and 105th to the 145th DAF), where the rate of oil accumulation increased significantly. At the last stage of maturation, the lentisc fruits had the highest percentage of lipid content, 42.54%. The changing profile of fatty acids during maturation had been marked mainly by an increase in oleic acid content (from 19.49% to 50.72%) paralleling a decrease in linoleic acid content (from 42.5% to 21.75%). At the 15th DAF, the alpha-linolenic acid was found with a maximum of 13.81%. At full maturity, the main fatty acids were oleic acid, followed by palmitic and linoleic acid. Other fatty acids were present in trace proportions, such as palmitoleic, stearic, linolenic, gadoleic and arachidic acid. In all stages of ripening only four sterols were identified and quantified. β-Sitosterol was the major 4-desmethylsterol in samples tested, followed by campesterol. Cholesterol and stigmasterol were detected in trace amounts. During the first stage of ripening, the amount of total sterols was about 5.19/100 g of oil. It decreased to 0.43/100 g in the last stage. Sitosterol and campesterol showed nearly the same profile during the ripening of P. lentiscus fruit which could be linked to the relation between these compounds during their biosynthesis.     

黍稷籽粒含油量及脂肪酸组成分析

研究分析18个黍稷（Panicum miliaceum L.）品种的籽粒含油量和脂肪酸组成。结果表明,黍稷籽粒含油量为2.54%~4.00%,均值3.71%。黍稷籽粒中主要脂肪酸为亚油酸（18:2n6）、油酸（18:1n9）和棕榈酸（16:0）,含量区间分别为0.075~5.19、0.150~3.02和0.897~1.81 g/100 g,并含有棕榈油酸、硬脂酸、亚麻酸、花生四烯酸、二十二烷酸和二十四烷酸。不饱和脂肪酸（UFA）占总油脂的82.1%~ 94.6%。相关性分析和主成分分析的结果表明,10种脂肪酸含量存在显著的相关性。聚类分析表明,脂肪酸组成在黍稷品种间的差异显著。     

猫屎瓜籽油脂肪酸组成及理化性质分析

采用冷榨法提取猫屎瓜籽油,用气相色谱法分析油中脂肪酸组成,根据相关的国家标准对油的理化性质进行了测定.结果表明,冷榨所得到的猫屎瓜籽油为淡黄色,清亮透明,有淡淡的清香味.猫屎瓜籽油主要脂肪酸成分为单不饱和脂肪酸棕榈油酸,含量为49.9%,占油中脂肪酸成分的一半.其余成分为:肉豆蔻酸0.2%,棕榈酸9.7%,硬脂酸1.7%,油酸27.5%,亚油酸10.1%,亚麻酸0.8%.此外,该油的酸值(KOH)、碘值(I)、过氧化值分别为3.1 mg/g、97 g/100 g和3.9 mmol/kg.     

Total lipids content and fatty acid composition of seed oils from six pomegranate cultivars

The fatty acid composition of the seed oils of six pomegranate (Punica granatum L) cultivars was qualitatively and quantitatively determined by gas chromatography. The seeds contained oil in the range 51-152 mg kg^?1 dry matter. Intervarietal differences in fatty acid composition were demonstrated (fatty acid esters as % (w/w) total fatty acid esters. Sour varieties had the highest while sour-sweet varieties had the lowest oil content. Eleven fatty acids were identified. In all varieties, the predominant fatty acids were linoleic (25.2-38.6%) and oleic acid (24.8-35.5%) followed by palmitic (18.2-22.6%), stearic (6.9-10.4%) and linolenic acid (0.6-9.9%). To a lesser extent arachidic (1.1-3.4%) and palmitoleic acid (0.2-2.7%) were also found in all varieties. Lauric, myristic, behenic and lignoceric acids were rarely detected. As far as we know linolenic (18:3), arachidic (20:0), behenic (22:0) or lignoceric (24:0) acids have not been previously reported in the seed oils of edible pomegranate varieties. Lignoceric acid has not previously been found in pomegranate seed oil.