OXIDATIVE STABILITY OF PORK PEPPERONI DURING PROCESSING AND DIFFERENT PACKING AND STORAGE CONDITIONS AS INFLUENCED BY FAT SOURCE

Pepperoni made from pigs fed diets containing fishmeal and different fat sources was studied for changes in fatty acid composition, oxidation and sensory characteristics during ripening and different storage condition. Fatty acid composition did not change during processing and ripening. Oxidation was low for all groups after processing and ripening, and vacuum and MAP packing kept oxidation low at 6C. Pepperoni from pigs fed lamb tallow (LT) and hydrogenated fish oil (HFO) had, however, developed unacceptable flavor changes at 6C. Oxidation proceeded rapidly at 23C with the HFO group leading. Lower storage quality of the HFO group pepperoni could be from more polyunsaturated fatty acids. Inclusion of HFO and LT at 5% into pig feed was determined unacceptable but 9% high quality fishmeal without any added fat sources appears acceptable. Measured oxidation values (peroxide and p-anisidine values) may not be good indicators of flavor changes of pepperoni during storage.     

A healthier oil combination and konjac gel as functional ingredients in low-fat pork liver pâté

Healthier lipid patés were formulated by reducing the fat content and/or replacing the pork backfat by a healthier oil combination (olive, linseed and fish oils) and konjac gel (0-15%). The reformulation results were evaluated by composition (proximate analysis and fatty acid profile), technological properties (emulsion stability, colour, and texture), microbiological and sensory parameters of the patés. Patés with partial or total replacement of pork backfat had lower levels of saturated fatty acids (SFA) (27.4% and 21.3%) and monounsaturated fatty acids (MUFA) (49.8% and 42.5%), and higher levels of polyunsaturated fatty acids (PUFA) (22.4% and 35.6%) compared with control patés (32.2%, 58.2% and 9.04% respectively). The n-6/n-3 PUFA ratio was decreased from 6.78 (in control patés) to 0.79 and 0.48 when partial and total pork backfat respectively was replaced by a healthier oil combination. Although emulsion stability was affected by the formulation, in general all patés had good fat and water binding properties. The fat reduction produced a softer and more spreadable paté, although no effect on penetration parameters was observed after by pork fat replacement by a healthier oil combination. The addition of 15% of konjac gel produced stiffer structures (as compared with 0 and 7%) which are very close to those of the control samples. No microbiological limitations were produced by the reformulation process, obtaining patés with acceptable sensory characteristics, similar to the control sample.     

Changes in fatty acid composition and improved sensory quality of backfat and meat of pigs fed bacterial protein meal

A total of 48 pigs (11.4 and 107.2 kg initial and final weight) were used to evaluate increasing dietary levels of bacterial protein meal (BPM) produced on natural gas (0, 50, 100, or 150 g kg⁻¹) on fatty acid composition, sensory properties, and susceptibility of pork to lipid oxidation. Increasing levels of BPM to diets increased the content of C16:1 fatty acids in backfat and muscle and total monounsaturated fatty acids in muscle, but decreased the content of polyunsaturated fatty acids and iodine value in backfat and muscle. Pigs fed diets containing BPM had reduced thiobarbituric acid reactive substances (TBARS) value in backfat and muscle, reduced intensity of odor and rancid odor and taste in pork after short-time storage, and reduced off-odor and off-taste after intermediate-time storage. To conclude, adding BPM to diets for pigs changed the fatty acid profile, improved the oxidative stability, and sensory quality of pork.     

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.     

豉香型白酒肥肉浸制产脂肪油及脂质氧化研究

以黑米、黑豆、黑木耳为原料,以木糖醇代替蔗糖,将黑米黑豆黑木耳混合液与牛乳共同发酵,研制一种低糖复合发酵乳,并采用单因素及正交试验优化其发酵工艺条件。结果表明,通过高温烘焙香气试验确定黑米、黑豆烘烤条件分别为160 ℃烘烤8 min、180 ℃烘烤10 min。低糖复合发酵乳的最佳工艺条件为黑米∶黑豆∶黑木耳=3∶2∶1（g∶g）,黑米黑豆黑木耳混合液∶牛乳=6∶4（V/V）,混合菌种（保加利亚乳杆菌∶嗜热链球菌=1∶2）接种量4.0%,木糖醇添加量8%。在此优化工艺条件下,低糖复合发酵乳的感官评分为94.2分,脂肪含量为3.6%,蛋白质含量为5.9%,酸度为79 °T,还原糖含量为5.2%,全乳固体为16.1%;乳酸菌数为1.91×106 CFU/g;未检出致病菌,符合相关国家标准。     

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 replacing pork backfat with emulsified vegetable oil on fatty acid composition and quality of UK-style sausages

Rapeseed and sunflower oil were used to replace pork backfat in UK-style sausages by incorporating the oils as pre-formed emulsions. Replacing the pork backfat emulsion with rapeseed emulsion at total fat content of about 12%, reduced total saturated fatty acid (SFA) composition from 38% to 14% (4.5 to 1.8 g/100 g), increased monounsaturated fatty acid (MUFA) composition from 45% to 59% and increased polyunsaturated fatty acid (PUFA) composition from 15% to 25%. Partial replacement of pork backfat with rapeseed at a fat content of about 20% reduced SFA from 38% to 24% (7.2 to 4.8 g/100 g). There were no significant differences in eating quality and overall liking other than slight differences in the attributes ‘firmness’ and ‘particle size’. Improvement in the fatty acid composition was achieved without adversely affecting colour shelf life or lipid oxidation. The study suggests that a substantial reduction in SFA can be achieved by incorporating ‘healthy’ oils in UK-style sausages without adversely affecting eating quality or shelf life.     

The composition of the fatty acids and aldehydes of the ethanolamine and choline phospholipids of various meats

The ethanolamine phospholipids of beef, lamb, pork and chicken examined in this study contained over 40% of ethanolamine plasmalogen, whereas fish contained only 13%. The level of choline plasmalogen in choline phospholipids was less than 1% in fish and ranged from 10 to 30% in the other four meats. Palmitaldehyde was the major fatty aldehyde in the choline plasmalogens of beef, lamb, pork and chicken (65–80% of total aldehydes), but was present at lower levels in the ethanolamine plasmalogens. The per cent fatty acid compositions of phosphatidylethanolamine and the corresponding ethanolamine plasmalogen were very similar, being typically low in palmitic acid but very high (56–74%) in polyunsaturated fatty acids. The fatty acids of the choline plasmalogens contained more polyunsaturated fatty acids than the corresponding phosphatidyl cholines, but at lower levels than in the fatty acids of the ethanolamine phospholipids.     

LIPID OXIDATION AND SENSORY CHARACTERISTICS OF FRESH AND CURED SAUSAGES FROM α-LINOLENIC ACID ENRICHED PORK

Forty-eight female piglets were raised with four levels of α-linolenic acid (0, 1.5, 2.5, 3.5%) to determine the effect of dietary fat on the fatty acid composition, sensory and storage stability of pork products. The degree of polyunsaturation in neutral lipids and phospholipids were increased significantly by the dietary LNA. The thiobarbituric acid reactive substances (TBARS) vaues of freshly prepared breakfast sausages with vacuum packaging remained low, but those of the loosely packaged, i. e., nonvacuumized, sausages increased more than 3 times during the 48 h storage period. The TBARS values of breakfast sausages frozen-stored for 3 months showed extensive lipid oxidation. The dietary LNA treatments and packaging had significant effects on the susceptibility of breakfast sausages to lipid oxidation. However, the oxidative stability of cured products was not affected by the dietary treatments. The results indicated that the pork enriched with polyunsaturated fatty acids could be used in cured products or uncured meat products protected by ‘hot vacuum packaging’without any sensory or quality deterioration due to lipid oxidation.     

Enhanced resistance of mice (CBA strain) to infection caused by S. typhimurium depending on the nature of the fat in the diet

Mice received rations containing a mixture of lard with sunflower oil, butter, cooking fat (hydrogenated), fish fat. Hydrogenated fat and fish fat induced a decrease in the portion of polyunsaturated fatty acid omega 6 in lipids of lymphocytes, Peyer's patches, mesenteric lymph nodes and the spleen. At the same time fish fat induced an increase of the portion of polyunsaturated fatty acid omega 3 in lipids studied. A relationship has been noted between the animal survival after intraperitoneal infection with S. Typhimurium and the fatty acid composition in lymphoid tissues. The highest survival rate has been recorded in the groups of animals that received cooking (hydrogenated) fat and fish fat.     

OXIDATION OF LIPIDS IN SARCOPLASMIC RETICULUM OF MUSCLES FROM PASTURE- AND GRAIN-FED CATTLE WITH OR WITHOUT VITAMIN E SUPPLEMENTATION

The effect of different α-tocopherol contents in sarcoplasmic reticulum (SR) membranes on lipid oxidation was investigated. Muscle membranes contain high contents of polyunsaturated fatty acids that are very susceptible to oxidation during chilled or frozen storage. SR was prepared from M. longissimus dorsi, M. semimembranosus and M. gluteus medius muscles of pasture- and grain-fed steers supplemented with vitamin E (0, 500 or 2500 IU α-tocopheryl acetate) for 105 -132 days. Vitamin E supplementation increased the α-tocopherol concentration in SR of grain-fed cattle but did not change that of pasture-fed cattle. SR from pasture-fed beef had more linolenic and less linoleic acid than that of grain-fed meat and, compared with the other treatment groups, SR of control grain-fed cattle was significantly more prone to lipid oxidation, corresponding with its lower α-tocopherol content. Thus, α-tocopherol content appears to play a major role in determining the extent of lipid oxidation in muscle membranes, especially in those from pasture-fed beef that contained more polyunsaturated fatty acids.     

Muscle lipids, vitamins E and A, and lipid oxidation as affected by diet and RN genotype in female and castrated male Hampshire crossbreed pigs

The objectives of this study were to investigate the polar and neutral lipid fatty acid composition, content of retinol, -tocopherol, γ-tocopherol and level of oxidation of the pig muscle (M. longissimus dorsi). Female and castrated male Hampshire crossbreeds were produced in two systems. One group was raised indoors with a more polyunsaturated diet and the other raised outdoors with a more saturated diet. The level of polyunsaturated fatty acids in muscle was higher in the indoor females compared with the outdoor females, indoor castrated males and outdoor castrated males. The increased level of polyunsaturated fatty acids in the muscle, which was accompanied by a relatively low content of -tocopherol, increased the susceptibility to lipid oxidation in the form of MDA (malondialdehyde) in the indoor female pigs. Finally, the level of polyunsaturated fatty acids in the polar lipids was affected by the RN genotype, and this difference was dependent on sex. In conclusion, diet has a major effect on the fatty acid composition and oxidation stability in pork muscle, but additional factors such as sex and RN genotype might also contribute.     

Partial substitution of pork backfat with extra-virgin olive oil in 'salami' products: effects on chemical, physical and sensorial quality

The effects on chemical, physical and sensory quality of the partial substitution of pork backfat with extra-virgin olive oil were studied in 'salami' products. Four 'salami' formulations, with 15% total fat, were prepared, in which 0, 33.5, 50 and 66.5% of pork backfat was substituted with extra-virgin olive oil. The partial pork backfat substitution with extra-virgin olive oil did not substantially affect the chemical, physical and sensorial characteristics of products, with the exception of water activity and texture. With regard to both oxidation and loss of organoleptic quality, the addition of extra-virgin olive oil, rich in mono-unsaturated fatty acids, did not decrease the shelf-life. The difference between samples with and without extra-virgin olive oil was a piquant note detected in the oil-added 'salami'. The formulation with 5% olive oil, corresponding to 33.3% substitution of pork backfat with olive oil, was judged best of all formulations. The results show that it is possible to produce this type of product, of good taste, similar to the traditional one, but with healthier features.     

Lipid oxidation of stored eggs enriched with very long chain n−3 fatty acids,as affected by dietary olive leaves (Olea europea L.) or α-tocopheryl acetate supplementation

The antioxidant potential of dietary olive leaves or α-tocopheryl acetate supplementation on lipid oxidation of refrigerated stored hen eggs enriched with very long-chain n−3 fatty acids, was investigated. Ninety-six brown Lohmann laying hens, were equally assigned into three groups. Hens within the control group were given a typical diet containing 3% fish oil, whereas other groups were given the same diet further supplemented with 10 g ground olive leaves/kg feed or 200 mg α-tocopheryl acetate/kg feed. Results showed that α-tocopheryl acetate or olive leaves supplementation had no significant effect on the fatty acid composition and malondialdehyde (MDA) levels of fresh eggs but reduced their lipid hydroperoxide levels compared to controls. Storage for 60 d decreased the proportions of polyunsaturated fatty acids (PUFAs) but increased those of monounsaturated fatty acids (MUFAs) in eggs from the control group, while had no effect on the fatty acid composition of the eggs from the other two groups, which showed decreased levels of lipid hydroperoxides and MDA. Therefore, the very long chain n−3 PUFAs in eggs were protected from undergoing deterioration partly by olive leaves supplementation and totally by α-tocopheryl acetate supplementation. In addition, incorporating tocopherols into eggs might also provide a source of tocopherols for the human diet.     

Development of combinations of chemically modified vegetable oils as pork backfat substitutes in sausages formulation

Today’s consumers look for foods which provide nutrition and pleasure, while safeguarding their health, the result of which is that they increasingly avoid foods containing cholesterol and saturated and trans fatty acids. Chemically modified vegetable oils can help tailor meat products to meet this growing need and at the same time fulfil the technological needs of the meat processing industry. In this study, 16 backfat samples were characterised for their solid fat content (SFC) and melting point and these characteristics were used to design a mixture of chemically modified vegetable oils for use as a pork fat substitute for elaborating sausages. The mixtures were prepared with different vegetable oils bearing in mind with stearic acid content due to its close correlation with the SFC. The backfat was characterised as a function of its SFC and some modified vegetable oil mixtures were proposed, which led to a 10–20% diminution in saturated fatty acids and with a melting point similar to those observed in the backfat. The fatty acid profile pointed to a polyunsaturated/saturated fatty acids ratio higher than 0.4, and an n − 6/n − 3 fatty acid ratio of less than 4 in both modified vegetable oil mixtures proposed.     

多不饱和脂肪酸对大鼠大脑细胞膜脂肪酸组成的影响

研究多不饱和脂肪酸(PUFAs)对发育期大鼠大脑细胞膜脂肪酸类别与含量的变化。将56只初断乳雄性SD大鼠随机分为阴性组、必需脂肪酸(EFA)缺乏组、鱼油组[300mg/(kg·d)]、紫苏组[2.45mL/(kg·d)]、α-亚油酸组[1.32g/(kg·d)]、核桃组[2.45mL/(kg·d)]与红花组[1.65g/(kg·d)]。连续饲养8周,提取大脑组织总细胞膜,并使用气相色谱-质谱联用技术检测其脂肪酸的种类与含量。结果表明,各组大鼠脂肪酸组成无差别;与阴性组比较,各组均能显著提高n-3PUFAs的含量;紫苏组、核桃组和红花组能显著降低n-6PUFAs的含量,增加饱和脂肪酸的含量;紫苏组、核桃组、红花组和鱼油组能显著降低单不饱和脂肪酸的含量。说明PUFAs能改变大鼠大脑细胞膜的含量,但对其类别影响不大;短期缺乏EFA对细胞膜脂肪酸的类别与含量无影响。     

富含n-3LC-PUFA调和油的家庭烹饪氧化稳定性研究

通过对DHA和EPA质量分数分别为0.23%、0.45%、0.90%、1.80%的调和油进行家庭炒菜试验的研究,考察了富含n-3长碳链多不饱和脂肪酸(Long chain polyunsaturated fatty acid,LC-PUFA)的调和油的家庭烹饪氧化稳定性。结果表明:炒土豆丝后,上述油样中DHA和EPA的损失分别为1.2%、2.9%、2.4%、1.4%;炒青椒肉片后其损失分别为:3.0%、2.2%、2.4%、4.5%。炒菜前后调和油的各项指标包括羰基价、总氧化值(TOTOX)、硫代巴比妥酸值(TBA)、酸价和聚合物含量与大豆油(对照样1)以及不含DHA和EPA的调和油(对照样2)相比,油样的氧化程度以及油脂品质与两个对照样接近。不同DHA和EPA含量的调和油炒菜之后其多不饱和脂肪酸保留率在95%以上,氧化稳定性和豆油接近,适合家庭烹饪。     

A process for the synthesis of PUFA-enriched triglycerides from high-acid crude fish oil

This paper reports a research interest, that aims to establish a feasible industrial process, for the enzymatic production of glycerides with highly concentrated n-3 polyunsaturated fatty acids (eicosapentaenoic acid and docosahexaenoic acid), from high-acid crude fish oils. The process covers enzymatic deacidification of crude fish oil, alkaline-based synthesis of polyunsaturated fatty acids ethyl esters, concentration of polyunsaturated fatty acids ethyl esters, and enzyme catalyzed synthesis of polyunsaturated fatty acids glycerides. Commercial available immobilized lipase, Novozym 435, was used as the catalyst. The synthesized glycerides contained 5.5% of eicosapentaenoic acid and 74.6% of docosahexaenoic acid, which was 1.21 and 2.71 times more than that in the original fish oil, respectively. The application of the designed process was successfully proved by a 100-fold scale-up reaction.     

Effect of different cooking methods on the oxidation,proximate and fatty acid composition of silver catfish (Rhamdia quelen) fillets

The influence of seven cooking methods (boiling, conventional baking, microwave baking, grilling, deep-frying in soybean oil, canola oil, or partially hydrogenated vegetable oil) on the oxidation, proximate and fatty acid composition of silver catfish (Rhamdia quelen) fillets was evaluated. All the treatments reduced moisture and increased the protein content. The free fatty acid content of the fillets was significantly reduced by the different cooking methods, while conjugated diene levels and peroxide values decreased for all fried samples, but remained constant in the samples subjected to the other cooking methods. Boiling and baking increased thiobarbituric acid reactive substances (TBARS), while grilling and frying did not change TBARS. Boiling, baking, and grilling did not affect the silver catfish fillets fatty acid composition. Frying in canola oil increased n−3/n−6 ratio, while frying in soybean oil increased the general polyunsaturated fatty acid content, and frying in hydrogenated vegetable oil incorporated trans fatty acids in the fillets.     

Nutritional and sensory properties of dry fermented sausages enriched with n-3 PUFAs

Enrichment of dry fermented sausages with n − 3 fatty acids through a partial substitution of pork backfat by deodorised fish oil resulted in improved nutritional properties with regard to conventional sausages, without affecting sensory properties and oxidation status. The developed products supplied 0.64 g EPA/100 g and 0.46 g DHA/100 g product, and showed PUFA + MUFA/SFA ratio of 1.76 and n − 6/n − 3 ratio of 2.97. No signs of oxidation were found in any type of sausages, control and modified. None of the dienals and trienals reported as secondary lipid oxidation products and typical for fish oil were detected in the modified sausages. Instrumental colour differences were detected, however, without relevance in the sensory analysis. The sensory evaluation panel did not find differences in general acceptability. The modified dry fermented sausages can be considered a technologically viable functional food.