Influence of dietary oils and protein level on pork quality. 1. Effects on muscle fatty acid composition, carcass, meat and eating quality

This study evaluated the effects of three dietary oils - palm kernel (PKO), palm (PO) and soyabean (SBO) - and two protein levels - high (HP) and low (LP) in a 3×2 factorial design involving 60 pigs on growth performance, muscle fatty acid composition and content, carcass, meat and eating qualities. Oil type did not have a significant effect on growth and carcass quality. PKO significantly reduced the polyunsaturated (PUFA) to saturated (SFA) fatty acid (P:S) ratio in longissimus muscle (P<0.001). PKO increased the concentrations of lauric (12:0), myristic (14:0), palmitic (16:0) and stearic (18:0) fatty acids and decreased linoleic acid (18:2). The LP diet increased intramuscular fat (IMF) from 1.7g/100g muscle in HP to 2.9g/100g (P<0.001), increased tenderness by 0.6 units (P<0.01) and juiciness by 0.5 units (P<0.01) on the 1-8 scale, but at the expense of lower daily weight gain (P<0.01), lower feed conversion efficiency (P<0.01), reduced P:S ratio (P<0.001) and increased lipid oxidation (P<0.01). The results suggest that PKO and PO could be used in tropical developing countries as cheaper alternatives to SBO for the production of good quality and healthy pork, but their limits of inclusion need to be determined.     

Heat-oxidation stability of palm oil blended with extra virgin olive oil

Rancimat induction time of palm oil (PO), several extra virgin olive oils (EV) and their binary blends have been determined at three different temperatures (120, 130 and 140°C). Analytical composition and oxidation stability of PO/EV blends were found to be a linear combination of the oil partners. Induction time of pure PO was always higher than those of EV oils and blends, in which induction time increased proportionally with the percentage of PO. However, induction time of 80% PO blend was similar to that of pure PO. Fatty acid composition appeared to be the most important factor affecting heat-oxidation stability and a saturated/unsaturated ratio near 1 was the optimally stable composition. Conversely, total phenols had a zero or negative role on the oxidative stability of the blends. Finally, in heat-oxidised oils significant losses of polyunsaturated fatty acids and formation of short-chain fatty acids were recorded.     

Optimizing palm oil and palm stearin utilization for sensory and textural properties of chicken frankfurters

This study was designed to explore the potential of refined, bleached and deodorized (RBD) palm oil (PO) and palm stearin (POs) utilization in chicken frankfurters. A 10 points augmented simplex-centroid design was used to study the effect of chicken fat (CF), PO and POs as well as the interaction of these fats on the emulsion, textural and sensory properties of chicken frankfurters. All frankfurters were formulated to contain approx 25% fat, 52% moisture and 10% protein. No significant difference was found in end chopping temperatures of all meat batters even though the temperature of PO and POs upon incorporation into meat batters was 50°C higher than CF. Strong emulsions were formed as no fluid losses were observed in all the meat batters tested after heating. Texture profiles of the frankfurters containing PO and/or CF were quite similar, but increment of POs raised hardness, chewiness, and shear hardness of the frankfurters. Acceptability of the frankfurters was evaluated using hedonic test. Panelists found no difference in hardness preference between frankfurters made from totally CF and PO, while frankfurters made from POs were rated as hard and brittle. CF was important in determining acceptability of the frankfurters, as reduction of CF in formulation resulted in lower scores in chicken flavor, juiciness, oiliness and overall acceptance of the frankfurters. Frankfurters with sensory acceptability comparable to a commercial one were found to comprise of more than 17% CF, and less than 67% PO and 17% POs of the fat blend.     

Interpretation of triacylglycerol profiles of palm oil,palm kernel oil and their binary blends

The effects of lipase-catalyzed interesterification (IE) on changes in the chemical composition of palm oil (PO), palm kernel oil (PKO) and their binary blends at 3:1, 1:1 and 1:3 (w/w) ratios, using both 1,3 specific Rhizomucor miehei, (Lipozyme™) and non-specific Pseudomonas sp. lipases were evaluated. IE of the native PO and PKO showed very distinct chemical composition changes. Catalysis of PO, using both lipases, caused synthesis of more medium and long chain triacylglycerols (TAG), with MMM/OLL, MMP, OOO and PPP (M, myristic acid; O, oleic acid; L, linoleic acid; P, palmitic acid) increasing in concentration. In contrast, IE of PKO resulted in the formation of more short and medium chain TAG, with LaLaO and LaMO (La, lauric acid; C, capric acid) experiencing noteworthy increments. Both Rhizomucor miehei and Pseudomonas sp. lipases showed high affinity in hydrolyzing PO fatty acids, resulting in high TAG losses and formation of high percentages of partial glycerides while these lipases were found to enhance the synthesis process in IE of PKO. Catalysis of the three binary blends caused similar TAG compositional changes where the synthesis process focussed on the medium chain TAG, while hydrolysis was observed in the short and long chain TAG that showed corresponding decreases. Catalysis of the three blends was influenced by the major fraction of these blends. Among these blends, PO: PKO at a 1:1 ratio exhibited the highest degree of IE. The diversity and quantity of available TAG are postulated to be the main causes of the different catalytic activities in these binary blends with Pseudomonas sp. lipase showing a higher degree and rate of IE than R. miehei.     

Influence of composition on degradation during repeated deep‐fat frying of binary and ternary blends of palm,sunflower and soybean oils with health‐optimised saturated‐to‐unsaturated fatty acid ratios

The American Heart Association recommended the fatty acid balance contributed by all the fats in our diet, suggesting it would be best at approximately 1:1:1 for saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), respectively. Three individual oils: palm oil (PO), soybean oil (SBO) and sunflower oil (SNF) and their binary and ternary blends were prepared and used for repeated deep‐fat frying of French fries. The acid value, peroxide value, p‐anisidine value and Totox values, as well as oxidative stability, contents of total polar compounds, tocochromanols, triacylglycerol dimers and oligomers, were determined in individual and blended oils. The lowest Totox value and highest stability were found for PO, and the opposite data were obtained for SNF and SBO. The degradation of tocochromanols in blends ranged from 91% to 95% after 4 days of frying, while in individual oils, it was 63% in SBO, 71% in SNF and 100% in PO. The lowest formation of dimers and oligomers was observed for the PO: SNF blend. Obtained results showed that only pure PO was a better frying medium than its blends with SBO and SNF. However, a prepared blend had a better fatty acid composition for human health and was more stable than pure SBO and SNF.     

Effect of dietary fat type on meat quality and fatty acid composition of various tissues in growing-finishing swine

Thirty-six castrated male growing pigs were used to study the effect of dietary beef tallow (BT) versus sunflower oil (SO) on meat quality and fatty acid composition of various tissues. The diets used contained either 5% (w/w) of the variable fat source. The fat type had no significant effect on carcass traits (carcass weight, back-fat thickness, fat-lean ratio) and meat quality (colour, pH(1), pH(U), drip losses, cooking losses, shear force, sacromere length, loin moisture, loin marbling). The diet with SO instead of BT significantly increased the incorporation of polyunsaturated fatty acids in adipose tissues, loin and liver at the expense of the sum of saturated and monounsaturated fatty acids. In erythrocytes, the diet containing SO raised the contents of saturated and polyunsaturated fatty acids and lowered that of monounsaturated fatty acids. In particular, the SO diet produced an increase in the content of linoleic acid (C18:2n-6) in the various tissues. It is concluded that feeding a diet with SO instead of BT altered the fatty acid composition of tissues without simultaneously affecting various characteristics of meat quality.     

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。     

Physicochemical characteristics of soybean oil, palm kernel olein, and their binary blends

Soybean oil (SBO), palm kernel olein (PKO) and their binary blends (containing 5–40% PKO) were studied for their physicochemical characteristics. Decreases in band absorbencies of the resultant Fourier transform infrared spectra were observed in regions attributable to vibrations of the functional groups of unsaturated fatty acids, mainly the =C–H cis stretching at 3009 cm⁻¹and –C=C cis stretching at 1657 cm⁻¹. The solid fat content was measurable in the blends containing 15–40% PKO at 5 and 10 °C, ranging within 4–20% and 2–13%, respectively. The differential scanning calorimetry melting curve for SBO exhibited more complex transition peaks, suggesting a     polymorphic transformation when compared with PKO with a simpler     . Blending of SBO with PKO reduced the complexity caused by the polymorphic transformation, featuring the endotherms that only related to the β' fat crystals.     

酪蛋白酸钠-葵花籽油协同对乳化肠品质特性的影响

以猪后腿肉为原料肉,酪蛋白酸钠、葵花籽油预乳化液替代猪背膘制备乳化肠,研究不同比例（0、25%、50%、75%、100%）预乳化液替代对乳化肠蒸煮损失率、物理化学组成、色泽、质构、脂肪酸组成及硫代巴比妥酸值的影响。结果显示：随着预乳化液替代比例增加,乳化肠中蛋白质、水分的含量显著增加（P＜0.05）,灰分含量变化差异不显著,脂肪含量显著下降（P＜0.05）,从18.58%降低到10.17%;蒸煮损失率降低;乳化肠的亮度值随预乳化液代替猪背膘比例的增加呈上升趋势,红度值和黄度值呈下降趋势;预乳化液替代组乳化肠的质构特性优于对照组;预乳化液替代猪背膘制备乳化肠还可以改变乳化肠的脂肪酸组成,随替代比例的增大,乳化肠中必需脂肪酸亚油酸在总脂肪酸中所占的比例显著增加（P＜0.05）,多不饱和脂肪酸所占的比例增加,高达55.92%,饱和脂肪酸从39.72%降低到13.52%,满足消费者对低脂多不饱和脂肪酸肉制品的需求;随替代比例的增大,乳化肠的TBARS值逐渐减小,用预乳化液替代猪背膘可增强乳化肠的氧化稳定性。因此,酪蛋白酸钠、葵花籽油预乳化液替代猪背膘可显著改善乳化肠的品质及营养特性。     

Effects of incorporation of interesterified plant oils on quality and fatty acid composition of Turkish‐type salami

Application of interesterified plant oils (IPOs) prepared from palm, cottonseed and olive oil (IPaO, ICO and IOO, respectively) have been studied in Turkish‐type salamis. Beef fat (10%) was replaced by one of the IPOs for 20, 60 or 100%. Incorporation of IPO was well reflected in fatty acid composition and saturated fatty acids/unsaturated fatty acids (SFA/UFA) ratios of the lipid fraction of all batches. Significant differences in appearance, color, texture, flavour or total score were not found among the control and Turkish‐type salamis with different types and levels of IPO. We conclude that IPOs may be successfully applied as beef fat substitutes in Turkish‐type salami.     

Effects of monensin and dietary soybean oil on milk fat percentage and milk fatty acid profile in lactating dairy cows

The objective of this study was to investigate the effect of monensin (MN) and dietary soybean oil (SBO) on milk fat percentage and milk fatty acid (FA) profile. The study was conducted as a randomized complete block design with a 2 × 3 factorial treatment arrangement using 72 lactating multiparous Holstein dairy cows (138 ± 24 d in milk). Treatments were [dry matter (DM) basis] as follows: 1) control total mixed ration (TMR, no MN) with no supplemental SBO; 2) MN-treated TMR (22 g of MN/kg of DM) with no supplemental SBO; 3) control TMR including 1.7% SBO; 4) MN-treated TMR including 1.7% SBO; 5) control TMR including 3.4% SBO; and 6) MN-treated TMR including 3.4% SBO. The TMR (% of DM; corn silage, 31.6%; haylage, 21.2%; hay, 4.2%; high-moisture corn, 18.8%; soy hulls, 3.3%; and protein supplement, 20.9%) was offered ad libitum. The experiment consisted of a 2-wk baseline, a 3-wk adaptation, and a 2-wk collection period. Monensin, SBO, and their interaction linearly reduced milk fat percentage. Cows receiving SBO with no added MN (treatments 3 and 5) had 4.5 and 14.2% decreases in milk fat percentage, respectively. Cows receiving SBO with added MN (treatments 4 and 6) had 16.5 and 35.1% decreases in milk fat percentage, respectively. However, the interaction effect of MN and SBO on fat yield was not significant. Monensin reduced milk fat yield by 6.6%. Soybean oil linearly reduced milk fat yield and protein percentage and linearly increased milk yield and milk protein yield. Monensin and SBO reduced 4% fat-corrected milk and had no effect on DM intake. Monensin interacted with SBO to linearly increase milk fat concentration (g/100 g of FA) of total trans-18:1 in milk fat including trans-6 to 8, trans-9, trans-10, trans-11, trans-12 18:1 and the concentration of total conjugated linoleic acid isomers including cis-9, trans-11 18:2; trans-9, cis-11 18:2; and trans-10, cis-12 18:2. Also, the interaction increased milk concentration of polyunsaturated fatty acids. Monensin and SBO linearly reduced, with no significant interaction, milk concentration (g/100 g of FA) of short- and medium-chain fatty acids (<C16). Soybean oil reduced total saturated FA and increased total monounsaturated FA. These results suggest that monensin reduces milk fat percentage and this effect is accentuated when SBO is added to the ration.     

生物柴油原料中不皂化物和脂肪酸分析

旨在确定生物柴油原料的可利用性,以可作为生物柴油原料的木本植物油脂、餐饮废油和酸化油为研究对象,分析其不皂化物和脂肪酸组成及含量。结果表明：棕榈油等7种木本植物油脂不皂化物含量低于1.10%,脂肪酸含量均高于91.50%,脂肪酸组成以油酸、亚油酸和亚麻酸为主(除棕榈油外);餐饮废油的不皂化物含量变化较大,脂肪酸含量在83.99%～94.87%之间,大部分餐饮废油脂肪酸组成以亚油酸和亚麻酸为主;5种酸化油的脂肪酸含量在71.35%～92.05%之间,椰子酸化油饱和脂肪酸占比为80.06%,其他4种酸化油的脂肪酸组成以不饱和脂肪酸为主。综上,7种木本植物油脂是优良的生物柴油原料,餐饮废油和酸化油作为原料制备生物柴油时要严格控制其质量指标。     

Effect of cooking on the chemical composition of low-salt, low-fat Wakame/olive oil added beef patties with special reference to fatty acid content

Changes in chemical composition, with special reference to fatty acids, as affected by cooking, were studied in low-salt (0.5%)/low-fat patties (10%) with added Wakame (3%) and partial or total replacement of pork backfat with olive oil-in-water emulsion. The addition of Wakame and olive oil-in-water emulsion improved (P < 0.05) the binding properties and the cooking retention values of moisture, fat, fatty acids and ash, which were close to 100%. Partial and total replacement of animal fat with olive oil-in-water emulsion reduced (P < 0.05) saturated fatty acids (SFAs), while total replacement also reduced (P < 0.05) polyunsaturated fatty acid (PUFAs) contents. The fatty acid concentration in cooked patties was affected by product formulation. Unlike the case of all animal fat patties, when olive oil was added the cooking process increased (P < 0.05) SFAs, monounsaturated fatty acids (MUFAs) and PUFA n-3 (linolenic acid) and n-6 (linoleic acid) contents. Cooked formulated patties with seaweed and partial or total replacement of pork backfat by oil-in-water emulsion and with seaweed added were less calorie-dense and had lower SFAs levels, while samples with olive oil had higher MUFAs levels.     

Modelling the yield and texture of comminuted pork products using color and temperature. Effect of fat/lean ratio and starch

Practices to control the processing of finely comminuted meat products are proposed. The objective was to test the practical value of both temperature and light reflection measurements made during emulsification as potential indicators of cooking losses and resulting gel texture in pork sausages emulsified within a wide range of temperatures and starch and fat levels. Prior to cooking, pork batters were chopped for different times to ensure final emulsion temperatures ranging from 5 to 50°C. The effects of the fat/lean ratio (0.25 and 0.67) and starch addition (0.8 and 3.2% w:w) on temperature and optical reflection were also investigated. The chopping increased the temperature and decreased the light reflection of fresh meat emulsion. There was no relevant loss of emulsifying capacity at emulsion temperature below 30°C and lightness values over 70 CIE units. The losses and textural parameters of cooked emulsions could be predicted by means of non-linear regression equations based on the temperature and color of the raw emulsion. The determination coefficients obtained ranged from 0.89 to 0.99. The prediction models needed to be fitted to each batter formulation, especially in the presence of reduced levels of gelation agents (meat protein and starch). Lightness was a better predictor than chromaticity, since it decreased constantly with chopping in the range of final emulsion temperatures studied (5-50°C). This confirms previous studies that lightness could be used for monitoring emulsion stability in meat batters.     

不同热加工温度对牛肉干脂肪酸及脂肪氧化的影响

采用气相色谱-质谱联用技术,测定牛肉干中脂肪酸的组成,研究失水率相同时,不同干燥温度（25、55 ℃）及熟制温度（85、150 ℃）对牛肉干中脂肪酸组成和脂肪氧化的影响。结果表明：经热加工后,牛肉干的脂肪酸含量和脂肪氧化程度均有不同程度的变化。经55 ℃干燥后,不饱和脂肪酸（unsaturated fatty acid,UFA）、多不饱和脂肪酸（polyunsaturated fatty acid,PUFA）和单不饱和脂肪酸（monounsaturated fattyacid,MUFA）含量显著低于25 ℃干燥（P＜0.01）,饱和脂肪酸（saturated fatty acid,SFA）含量显著高于25 ℃干燥（P＜0.01）,且脂肪氧化程度低于25 ℃干燥;熟制阶段,25 ℃干燥后熟制,SFA、UFA、MUFA和PUFA含量变化不显著（P＞0.05）,而55 ℃干燥后,经150 ℃熟制,UFA、MUFA和PUFA含量显著低于85 ℃熟制（P＜0.01）,SFA含量显著高于85 ℃熟制（P＜0.01）,且脂肪氧化程度高。综上所述,不同干燥温度及熟制温度对牛肉干脂肪酸及脂肪氧化的影响不同,干燥阶段,较高温度（55 ℃）干燥对牛肉干脂肪氧化的影响小于25 ℃干燥;熟制阶段,较低温度（85 ℃）熟制对牛肉干脂肪氧化影响较小。因此,55 ℃干燥、85 ℃熟制得到的牛肉干产品,其UFA、MUFA和PUFA含量最高,SFA含量最低,脂肪氧化程度最小,牛肉干营养价值损失最小。     

Production of set yoghurt analogue through replacement of milk fat with canola and sesame oil

The aim of this study was to determine the effect of fat level and composition on chemical, textural, microbial and sensory properties of set yoghurt analogue. The best fat level for production of yoghurt analogue was found to be 2% (w/v). Studies on the effect of fat composition (canola‐to‐sesame oil ratios of 2.0/0, 1.3/0.7, 0.7/1.3, 2.0/0) indicated the superior performance of pure sesame oil. Increasing the canola‐to‐sesame oil ratio generally resulted in an inferior product. Replacement of milk fat by vegetable oils yielded yoghurts with a lower saturated fatty acid content and less firmness.     

Fatty acid composition and carcass characteristics of growing lambs fed diets containing palm oil supplements

Thirty 45-day-old male Ojalada lambs were used to investigate the effect of palm oil (as such or in the form of calcium soap) on carcass characteristics and fat composition. Dietary palm oil did not significantly affect dorsal fat thickness, carcass fatness or carcass conformation. The palm oil supplement did not affect C16:0 levels in intramuscular and subcutaneous fat, but did increase the percentage of C16:0 and reduce PUFA and MUFA content in internal fat depots. Supplementation with palm oil in the form of calcium soap did not cause significant differences in the composition of intramuscular fat. Subcutaneous and perirenal fat of lambs fed treatments including palm oil as such contained higher levels of some saturated fatty acids than that of those fed fat in the form of calcium soap. Mesenteric fat of lambs that received calcium soap had less % C18:1 and more % C18:3 than that of those given palm oil.     

Influence of dietary fat on pork eating quality

This study compared the influence of dietary fat sources on meat quality, fatty acid composition and sensory attributes in pork. The experiment was conducted with 43 entire male pigs (Pietrain×(Landrace×Large White)) which were fed a basal diet without added fat (control diet) or supplemented with different sources of fat: animal fat (1%, AF1; 3%, AF3), soyabean oil (1%, SBO1) and calcium soaps of palm oil (1%, CaSPO1). Dietary fat supplementation did not significantly affect ultimate pH, colour, Warner-Bratzler shear force values, sensory attributes or SFA. Pigs fed SBO1 had the lowest proportion of MUFA and the highest of PUFA. In conclusion, these dietary fat sources could be recommended for inclusion in diets, at these levels, with no detrimental effect on eating quality. Despite finding no significant differences, the PCA afforded a comprehensive view of the predominating attributes of pork from animals fed the different fats.     

泥鳅鱼籽营养成分及油脂的脂肪酸组成分析

以泥鳅鱼籽为原料,对其基本营养成分进行测定。采用正己烷-异丙醇提取法得到鱼籽油,对鱼籽油的理化指标及脂肪酸组成进行了测定,并与泥鳅鱼肉、鲫鱼籽、鲟鱼籽、林蛙卵以及母乳的油脂进行比较。结果表明：泥鳅鱼籽的营养成分为水分含量64.69%、蛋白质含量24.49%、脂肪含量5.62%、灰分含量1.56%;泥鳅鱼籽油理化指标为密度0.901 4 g/mL、折光率1.463 8、碘值105 g I/100 g、皂化值134 mg KOH/g;气相色谱-质谱联用分析可知,泥鳅鱼籽中不饱和脂肪酸含量为71.30%,其中油酸和亚油酸含量较高,分别为28.02%和24.51%。通过与泥鳅鱼肉、鲫鱼籽、鲟鱼籽、林蛙卵以及母乳的油脂比较,发现泥鳅鱼籽和母乳的饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸比例基本一致,非常接近健康食用油黄金比例1∶1∶1,而且泥鳅鱼籽的主要脂肪酸组成和母乳的基本相同,具有较高的开发和利用价值。     

Chopping temperature effects on the characteristics and chilled storage of low- and high-fat pork Bologna sausages

The object of this study was to investigate the influence of chilled storage (2 °C) and final chopping temperatures (8, 15 and 22 °C) on the characteristics and stability of Bologna sausage containing two levels of fat (8.5 and 23%). When the fat level was reduced there was a significant decrease in penetration force and an increase in both cooking and purge loss. A lower chopping temperature reduced purge loss during chilled storage. In general, an inverse relationship was found between chopping temperature and penetration force. Chopping temperature did not influence total aerobic count, but during chilled storage counts were significantly higher in the low fat sausages.