Prediction of fatty acid content in rabbit meat and discrimination between conventional and organic production systems by NIRS methodology

To investigate the feasibility of using the NIRS methodology to analyse the fatty acid content of rabbit meat and to discriminate between conventional and organic production, the meat of a hind leg of 119 rabbits was scanned between 1100 and 2498 nm and 104 samples were sent to the laboratory for reference analysis of fatty acids by gas chromatography. A commercial spectral analysis program (WINISI-2, v. 1.04) was used to process the data and to develop chemometric models. The better calibration equation for each fatty acid, leading to a higher determination coefficient of cross-validation (r²) and low standard error of cross-validation (SECV) was retained. Prediction of linoleic, palmitic, palmitoleic and oleic acid content was excellent or good (r² between 0.90 and 0.70); prediction of arachidonic, stearic, α-linolenic and eicosatrienoic FA has r² between 0.69 and 0.50. However, miristic, vaccenic, icosaenoic and eicosadienoic FA are problematic to predict. When fatty acids were grouped, the r² of the calibration equations were: 0.85 for saturated FA, 0.83 for MUFA, 0.92 for PUFA and 0.91 for n − 6 FA, indicating excellent or good prediction. Prediction of α-linolenic FA (r² = 0.59) needs more precision. The obtained equations have been applied for predicting meat fatty acid composition of both groups of production systems, conventional and organic, for an other 52 rabbit meat samples (2 × 26). Meat of the organic source had lower (p = 0.000) monounsaturated FA (30.54% vs. 34.64%) and higher (p = 0.019) polyunsaturated FA (27.28% vs. 23.66%) than rabbit meat from the conventional system, while the saturated FA content was similar (42%) in both groups. The discriminant model correctly classified (98%) between conventional or organic produced rabbit meat.     

伊拉兔生长过程中肉品质特性变化

为探讨生长过程中伊拉兔肉品质的变化,以伊拉兔配套系公兔为研究对象,测定不同日龄兔肉的食用品质和营养特性。结果表明：不同日龄下,伊拉兔肉的L*、pH值变化差异不显著（P＞0.05）;随着饲养时间的增加,水分含量显著下降（P＜0.05）,而蛋白质、粗脂肪和不饱和脂肪酸的含量显著升高（P＜0.05）;伊拉兔肉胆固醇的含量随日龄升高呈先上升后下降的趋势,且显著低于其他畜禽肉类;在75 d时,兔肉系水力、熟肉率、氨基酸总量及多不饱和脂肪酸/饱和脂肪酸的比值均最高,表明75 d的伊拉兔肉具有良好的加工特性且营养价值较高。     

Growth,carcass traits,chemical composition and fatty acid profile in beef from Charolais and Simmental bulls fed different types of dietary lipids

BACKGROUND: The effect of breed and whole sunflower seed on performance, carcass traits and the composition of meat was evaluated in Charolais (CH) and Simmental (SI) bulls. Samples of musculus longissimus lumborum (MLL) and musculus infraspinatus (MIS) were analysed. RESULTS: The CH bulls had a lower feed intake per kg of gain, a higher killing‐out percentage and produced more valuable carcasses. The muscles from SI bulls contained more monounsaturated fatty acids (FA) and less saturated FA (in g kg^?1 FA) than the muscles from CH bulls. The sunflower seed supplement increased the proportions of linoleic acid and c9t11 conjugated linoleic acid and the ratio of polyunsaturated fatty acids (PUFA) to saturated FA and decreased the index of atherogenicity of FA in meat lipids. CONCLUSION: The results of this study demonstrated the superiority of the CH over the SI breed in a number of economically important traits. The breed effect on the nutritional quality of meat was ambiguous. Meat lipids of the SI bulls contained more unsaturated FA but also more PUFA n‐6 and a higher PUFA n‐6/PUFA n‐3 ratio. Copyright © 2008 Society of Chemical Industry     

反复冻融对兔肉氨基酸和脂肪酸的影响

以新鲜兔肉为原料,研究反复冻融对兔肉蛋白质、氨基酸和脂肪酸含量的影响。结果发现：与新鲜兔肉相比,随着反复冻融次数的增加,兔肉中蛋白质含量显著减少（p＜0.05）,第4次冻融后,兔里脊、后腿蛋白质含量较新鲜兔肉分别下降了5.91%、10.30%;呈味氨基酸总量没有显著变化（p＞0.05）,但必需氨基酸和氨基酸总量显著减少（p＜0.05）,第4次冻融后的兔肉里脊部位赖氨酸含量比新鲜兔肉下降了16.42%;后腿部位的赖氨酸含量比新鲜兔肉下降了14.69%;脂肪酸总量、饱和脂肪酸含量、单不饱和脂肪酸含量和多不饱和脂肪酸含量均显著减少（p＜0.05）。结果表明反复冻融破坏了兔肉的营养成分,严重影响了兔肉的食用品质。     

Effects of different levels of trans fatty acids and oxidised lipids in diet on cholesterol and cholesterol oxidation products formation in rabbit

The objective was to assess the effects of trans fatty acids and oxidised lipids, present in dietary fat by-products used in feeds, on cholesterol and oxycholesterols in meat, liver and plasma of rabbits. A palm fatty acid distillate, before and after hydrogenation (trans fatty acid trial), and a sunflower–olive oil blend (70/30, v/v), before and after use in a commercial frying process (oxidised lipid trial), were used in experimental feeds (at 3%, w/w). High trans fatty acid and oxidised lipid diets caused significantly higher cholesterol and oxycholesterol levels in all tissues of rabbit (0.01 < p ? 0.05). The content of oxycholesterols in rabbit meat, liver and plasma obtained from trans fatty acid experiments varied from 9 to 34 μg/100 g, 24 to 61 μg/100 g and 60 to 138 μg/dl, respectively, from low to high levels. In the oxidised lipid experiments, content of oxycholesterols varied from 16 to 52 μg/100 g, 14 to 108 μg/100 g and 52 to 269 μg/dl in meat, liver and plasma, respectively. As a consequence, meat products from rabbits fed a diet containing higher levels of trans fatty acids or oxidised lipids may result in higher intakes of cholesterol and oxycholesterols by humans.     

Effect of fat-enriched diets on rabbit meat fatty acid composition

The effects of beef tallow-, soya and sunflower olein- and soya bean oil-enriched (3%) diets on the chemical and fatty acid composition of total, a polar and polar lipids of rabbit meat have been studied. No significant differences (P > 0.05) in the meat chemical composition were observed between groups. However, a large effect of the diet on the total and apolar lipid fatty acids was found, with C18:1 and C18:2 the most affected fatty acids. The influence of the diets on the fatty acids of the polar fraction was less marked. It is concluded that the enrichment of the rabbit diet with either soya and sunflower oleins or soya bean oil allows the production of rabbit meat with a higher unsaturation degree than is obtained by using conventional diets, which constitutes an important nutritional benefit to the human being.     

Effects of tomato pomace supplementation on carcass characteristics and meat quality of fattening rabbits

The aim of this study was to determine how a feeding plan characterized by different levels of tomato pomace (TP) supplementation influences the carcass characteristics, the chemical, physical and sensorial characteristics of rabbit meat. 144 weaned crossbred rabbits were divided into three groups of 48 each. The first group was fed a basal diet without TP, while the other two groups were fed the basal diet after replacing part of the diet with TP at 3% and 6%, respectively. There was a significant difference between the experimental groups in terms of live and carcass weights. The meat of rabbits fed on a 6% TP diet exhibited higher yellowness (b*) and Chroma values when compared to others. The saturated fatty acid content in the longissimus dorsi muscle and perirenal fat decreased significantly with increasing TP inclusion, while polyunsaturated fatty acids increased. Furthermore, our results indicate that a diet integrated with 6% TP could influence positively the overall preference of cooked meat.     

发酵剂对兔肉脯游离脂肪酸变化的影响

将兔肉糜中接种植物乳杆菌（Lactobacillus plantarum）、木糖葡萄球菌（Staphylococcus xylosus）、汉逊氏德巴利酵母（Dabaryomyces hansenii）,发酵及烘烤制成兔肉脯,研究3 种不同菌种接种发酵处理对兔肉脯中游离脂肪酸变化的影响,结果表明：总的游离脂肪酸含量均高于非接种菌组,其含量由高到低分别为葡萄球菌处理组＞酵母菌处理组＞植物乳杆菌处理组,说明添加的发酵剂促进了兔肉脯中脂肪的分解,而且它们在兔肉脯中分解产生游离脂肪酸的能力依次递减,各种脂肪酸的含量各有增减,说明不同的发酵剂对其作用不同。进一步研究3 种菌复合发酵处理对兔肉脯中游离脂肪酸影响情况,结果表明其总的游离脂肪酸含量及各种脂肪酸含量均高于单一菌接种组,说明3 种菌的复合发酵分解产生游离脂肪酸的能力较强。     

兔肉营养特点与人体健康

文章从我国居民营养素摄入现状出发,对近年来国内外兔肉营养成分的研究进行了综述,重点阐述了其脂肪酸的组成、胆固醇、氨基酸和矿物质的含量等,特别是它高蛋白质、低胆固醇、低热量、高比例的多不饱和脂肪酸、高赖氨酸、高钾低钠、高维生素B12的特点,是一种符合我国居民现代需求的优质肉品。     

Production of trans‐Free Margarine with Stearidonic Acid Soybean and High‐Stearate Soybean Oils‐Based Structured Lipid

Abstract: Omega‐3 fatty acids (n‐3 FAs) have been positively associated with prevention and treatment of chronic diseases. Intake of high amounts of trans fatty acids (TFAs) is correlated with increased risk of coronary heart disease, inflammation, and cancer. Structured lipid (SL) was synthesized using stearidonic acid (SDA) soybean oil and high‐stearate soybean oil catalyzed by Lipozyme^® TLIM lipase. The SL was compared to extracted fat (EF) from a commercial brand for FA profile, sn‐2 positional FAs, triacylglycerol (TAG) profile, polymorphism, thermal behavior, oxidative stability, and solid fat content (SFC). Both SL and EF had similar saturated FA (about 31 mol%) and unsaturated FA (about 68 mol%), but SL had a much lower n‐6/n‐3 ratio (1.1) than EF (5.8). SL had 10.5 mol% SDA. After short‐path distillation, a loss of 53.9% was observed in the total tocopherol content of SL. The tocopherols were lost as free tocopherols. SL and EF had similar melting profile, β’ polymorph, and oxidative stability. Margarine was formulated using SL (SLM) and EF (RCM, reformulated commercial margarine). No sensory difference was observed between the 2 margarines. The SL synthesized in this study contained no TFA and possessed desirable polymorphism, thermal properties, and SFC for formulation of soft margarine. The margarine produced with this SL was trans‐free and SDA‐enriched. Practical Application: The current research increases the food applications of stearidonic acid (SDA) soybean oil. trans‐Free SDA containing SL was synthesized with desirable polymorph, thermal properties, and SFC for formulation of soft margarine. The margarine produced with this SL had no trans fat and had a low n‐6/n‐3 ratio. This may help in reducing trans fat intake in our diet while increasing n‐3 FA intake.     

不同品种兔肉营养成分与质构比较研究

为丰富我国兔肉营养数据库,测定并分析四川、山东两地伊拉兔、伊高乐兔和伊普吕兔肉的水分、粗蛋白、粗脂肪、灰分、矿物质、氨基酸和脂肪酸等营养成分组成及含量以及硬度、弹性、胶着性等质构指标差异。结果表明：不同地区和品种兔肉的水分、蛋白质和脂肪含量存在显著差异（P＜0.05）,其中山东地区伊高乐兔肉水分含量最低、蛋白质含量最高,四川地区伊拉兔肉脂肪含量最低;不同地区和品种兔肉灰分、矿物质含量以及脂肪酸、氨基酸组成与含量无明显差异;山东地区伊高乐兔肉硬度低、弹性好、咀嚼性高,口感最好,四川地区伊普吕兔肉硬度高、胶着性高,口感最差。兔肉的营养成分与质构特性存在品种和地区差异,山东地区伊高乐兔肉营养成分和质构特性优于其他5种兔肉。     

Effect of slaughter season and muscle type on the fatty acid composition, including conjugated linoleic acid isomers, and nutritional value of intramuscular fat in organic beef

BACKGROUND: Consumer awareness regarding the intake of beef of organic origin is strongly associated with the beneficial outcomes to human health, the environment and animal welfare. In this paper the effects of slaughter season and muscle type on the fatty acid composition, conjugated linoleic acid (CLA) isomeric profile, total cholesterol, α‐tocopherol and β‐carotene contents and nutritional quality of intramuscular fat in organic beef (n = 30) are reported for the first time. RESULTS: Organic beef showed a very low total lipid content, with seasonal changes in the levels of some fatty acids, CLA isomers, n‐6/n‐3 polyunsaturated fatty acid (PUFA) ratio, total cholesterol and β‐carotene. In addition, differences between longissimus lumborum (relatively red) and semitendinosus (relatively white) muscles were found for many fatty acids, specific CLA contents, many CLA isomers and both PUFA/saturated fatty acid (SFA) and n‐6/n‐3 ratios. However, in spite of the seasonal and carcass variations, all organic meats analysed had values of beef similar to pasture‐fed cattle. CONCLUSION: From a nutritional perspective, organic meat from both slaughter seasons seems to have high CLA contents, PUFA/SFA and n‐6/n‐3 indices within the recommended values for the human diet. The data indicate that intramuscular fat in organic meat has a high nutritional value throughout the year. Copyright © 2012 Society of Chemical Industry     

Fatty acids, antioxidants and oxidation stability of processed reindeer meat

The effect of hot smoking and drying on reindeer meat (M. semimembranosus) was investigated with regard to vitamin content, fatty acids (FA), lipid oxidation and lipolysis. In smoked and dried meat, free fatty acids were found to increase (P<0.001), whereas polar lipids, cholesterol and triacylglycerols decreased. Only slight changes in FA composition of the smoked meat were found but the composition of the dried meat differed significantly from both smoked and fresh meat. Fresh and smoked meat were found to have low values (0.11 μg/g dry matter (DM); 0.21 μg/g DM) of thiobarbituric acid reacting substances but dried meat had high values (8.33 μg/g DM; P<0.001). Retinol was found only in the fresh meat and the tocopherol content decreased significantly (P<0.001) as a result of the processing. We conclude that the smoking process slightly changed FA composition, lipid class composition and vitamin content, whereas drying resulted in major changes in all the analysed parameters.     

Effect of genetic rabbit lines on lipid content, lipolytic activities and fatty acid composition of hind leg meat and perirenal fat

The influence of genetic origin on lipid content, lipolytic activities and fatty acid composition of rabbit leg meat and perirenal fat was studied and changes in free fatty acids and oxidative parameters during refrigerated storage evaluated. Three rabbits lines were used, line R selected for growth rate and lines V and A selected for litter size at weaning. Line R had higher fat contents and higher lipolytic activities in the meat of the hind leg than lines A and V. Differences between lines were found in the fatty acids of the meat and perirenal fat. Lower SFA and higher PUFA percentages were found in line A. Free fatty acids and oxidative parameters were little influenced by rabbit line. Animals were measured at the same stage of maturity, thus it can be considered that differences found between lines are genetic differences and not differences due to the degree of maturity.     

Lipase-catalysed production of triacylglycerols enriched in pinolenic acid at the sn-2 position from pine nut oil

BACKGROUND: The purpose of this study was to produce triacylglycerols (TAGs) enriched in pinolenic acid (PLA) at the sn‐2 position using the principle of acyl migration, from the pine nut oil containing PLA esterified exclusively at the sn‐3 position. RESULTS: Two types of lipase‐catalysed reactions, i.e. redistribution and reesterification of fatty acids, were successively performed using seven commercially available lipases as biocatalysts. Of the lipases tested, Novozym 435 and Lipozyme TL IM were effective biocatalysts for positioning PLA at the sn‐2 location. These biocatalysts were selected for further evaluation of the effects of reaction parameters, such as temperature and water content on the migration of PLA residues to the sn‐2 position and TAG content. For both lipases, a significant decrease in TAG content was observed after the lipase‐catalysed redistribution of fatty acids for both lipases. The reduced TAG content could be enhanced up to approx. 92%, through lipase‐catalysed re‐esterification of the hydrolysed fatty acids under vacuum. CONCLUSION: TAG enriched in PLA at the sn‐2 position was synthesised from pine nut oil via lipase‐catalysed redistribution and re‐esterification of fatty acid residues using Lipozyme TL IM and Novozym 435 as biocatalysts. Copyright © 2011 Society of Chemical Industry     

Meat fatty acid and cholesterol level of free-range broilers fed on grasshoppers on alpine rangeland in the Tibetan Plateau

BACKGROUND: Meat safety and nutrition are major concerns of consumers. The development of distinctive poultry production methods based on locally available natural resources is important. Grasshoppers are rich in important nutrients and occur in dense concentrations in most rangelands of northern China. Foraging chickens could be used to suppress grasshopper infestations. However, knowledge of the fatty acid content of meat from free‐range broilers reared on alpine rangeland is required. RESULTS: Rearing conditions and diet did not significantly (P > 0.05) affect concentrations of saturated fatty acid (SFA), arachidonic acid, docosahexaenoic acid or the ratio of total n‐6 to total n‐3 fatty acids. Breast muscle of chickens that had consumed grasshoppers contained significantly (P < 0.05) less monounsaturated fatty acid, but the ratio of polyunsaturated fatty acids (PUFA)/SFA and contents of total n‐3, total n‐6 and PUFA were significantly (P > 0.05) higher than intensively reared birds. Compared with meat from intensively reared birds, meat from free‐range broilers had less cholesterol and higher concentrations of total lipid and phospholipids. CONCLUSION: Chickens eating grasshoppers in rangeland produce superior quality meat and reduce the grasshopper populations that damage the pastures. This provides an economic system of enhanced poultry‐meat production, which derives benefits from natural resources rather than artificial additives. Copyright © 2012 Society of Chemical Industry     

Effect of feeding growing–fattening rabbits a diet supplemented with whole white lupin (Lupinus albus cv. Amiga) seeds on fatty acid composition and indexes related to human health in hind leg meat and perirenal fat

A total of 20 weaned rabbits (33 days old) (10 per treatment) were fed one of two diets that included 150 g of sunflower meal (SF)/kg of diet or 120 g of whole white lupin (WL)/kg of diet for 42 days. The WL diet contained less saturated fatty acids (SFA) and polyunsaturated fatty acids (PUFA) but more monounsaturated fatty acids (MUFA) than the SF diet. The WL diet significantly decreased SFA and PUFA content, as well as the PUFA n − 6/PUFA n − 3 ratio and saturation, atherogenic and thrombogenic indexes in hind leg meat. The fatty acid composition in perirenal fat was similar to that of hind leg meat; however, significantly higher MUFA levels were observed in rabbits fed the WL diet. Thus, feeding rabbits the WL diet affected the fatty acid profile of hind leg meat and perirenal fat in a favourable manner.     

Effect of different feeds on meat quality and fatty acid composition of lambs fattened at pasture

Two kinds of feed (commercial concentrate vs whole supplemented barley) were compared in unweaned lambs and lambs weaned at 40 days of age, fattened at pasture and slaughtered at 28 kg live weight, in order to observe their effects on meat quality and fatty acid composition. The weaning status influenced fatness; unweaned lambs displayed a greater carcass fatness score and more kidney knob and channel fat than weaned lambs. Compared with the unweaned animals, weaned lambs exhibited higher pH values at 0 h and 45 min in the m. longissimus thoracis (LT) and at 45 min and 24 h in the m. semitendinosus. The redness index (a*) of the m. LT of weaned lambs was higher than that of unweaned lambs, and lambs fed concentrate displayed a higher yellowness index (b*) and a higher Hue value than those given whole barley. Water-holding capacity did not vary with the treatments studied. The proportion of saturated fatty acids (SFA) in intramuscular fat was higher (P?0.001) in unweaned lambs than in weaned ones while, on the other hand, the latter displayed a higher proportion of monounsaturated fatty acids (MUFA) and a higher n-6/n-3 ratio in the same tissue. As was the case with intramuscular fat, the subcutaneous fat of unweaned lambs exhibited higher proportions of medium-chain fatty acids (C12:0, C14:0 y C16:0) and lower ones of stearic (C18:0) and oleic (C18:1) fatty acids than that of weaned lambs. Higher levels of heptadecenoic acid (C17:1) were found in the subcutaneous fat of lambs fed whole barley than in that of lambs given concentrate. PUFA/SFA and n-6/n-3 ratios were lower in the m. LT than in the m. quadriceps femoris.     

Lipid and fatty acid composition of rabbit meat: Part 2.-Phospholipids

The phospholipid contents (and their fatty acid composition) of the meat of two rabbit breeds (New Zealand white and the commercial hybrid HYLA) fed with two commercial diets of different protein and fibre contents, have been determined. The phospholipid contents in the meat of both rabbit breeds ranged from 9% to 19% total lipid. In this fraction seven different phospholipid classes were detected but phosphatidylcholine (PC) and phosphatididylethanolamine (PE) had average percentages of 50 and 20 of the total phospholipids. The major fatty acids of both phosphatidylcholine and phosphatidylethanolamine were C-16:0, C-18:0, C-18:1 and C-18:2, these together representing more than 70% of the total fatty acids. In general, the PC had an higher saturated fatty acid content than PE, which had a lower percentage of C-16:0 but higher C-20:4. Although differences in the fatty acid composition of the phospholipid fractions of the rabbit meat were observed, the only clear influences of age, sex, breed, and/or feeding were found with the C-16:0, C-18:0 and C-18:2 fatty acids.     

Relationships between meat quality measurements in rabbits fed with three diets of different fat type and content

Two hundred and eighty-four, genetically similar (a three-way cross), young rabbits were fed ad libitum, from weaning, either a commercial diet (group C, ether extract 2.6%) or a diet containing vegetable fat (group V, ether extract, 9.9%) or animal fat (group A, ether extract 11.7%). A principal component (PC) analysis was performed with the variables: ultimate pH at 24 h post mortem measured in the longissimus dorsi (LD) and in the biceps femoris (BF) muscles, colour measured on the surface of the loin, fatty acid composition of perirenal fat, meat fat content of the hind leg, water holding capacity and cooking losses of the meat, and sensory variables determined by a trained panel test. The four first PC explained 62% of the total variation (27, 13, 11 and 11%, respectively). The first PC grouped the fatty acids, the second PC grouped the sensorial variables, and the third and fourth PCs grouped the pHs and the water holding capacity. The projection of the data in the first two PCs showed three separate groups of points. Animals fed with diet V were on the left side of the graph, where the variable C18:2 lies, whereas animals fed with diets A and C lay on the right side of the graph, where the saturated acids were grouped. These were slightly separated by the higher content of oleic acid in the animals fed with diet A. The second PC, where the sensorial variables were grouped, did not separate the animals fed with diets A, V and C. The diets used in this experiment had only a slight influence on the organoleptic characteristics of rabbit meat.