Physicochemical and sensory properties of healthier frankfurters as affected by walnut and fat content

This study evaluates the physicochemical and sensory properties of healthier frankfurters with 25% added walnut (WF) versus low-fat frankfurters (6% pork fat) (LF) and traditional frankfurters (18% pork fat) (NF). Results reveal that cooking losses were unaffected (p ? 0.05) by the formulation of frankfurters. The addition of walnut led to higher (p < 0.05) redness and yellowness values, while colour parameters did not differ significantly between LF and NF sausages. Frankfurters with added walnut (WF) presented higher (p < 0.05) hardness and chewiness values than LF and NF frankfurters. Differences in composition were also accompanied by changes in the microstructure of the gel/emulsions. Frankfurters with added walnut presented a flavour significantly different from meat and scored lower (p < 0.05) on texture preferences. However, all frankfurters scored the same for overall acceptability.     

Low-fat Frankfurters with Elevated Levels of Water and Oleic Acid

The effects of simultaneous incorporation of maximum allowable levels of water and high-oleic sunflower oil (HOSO) on frankfurter properties were investigated. The formulation changes generally had little effect on processing yield. Frankfurters formulated with HOSO were 180-241% higher in the ratio of total monounsaturated fatty acids to total saturated fatty acids when compared to control products with similar total fat levels. Consumer-panel sensory data and instrumental texture profile data indicated that low-fat (14-16%), high-water, HOSO frankfurters- were as acceptable as control frankfurters with 28% fat (all-animal fat) and did not have the texture problems observed previously with low-fat, HOSO frankfurters without extra added water.     

Effects of diet fermentability and supplementation of 2-hydroxy-4-(methylthio)-butanoic acid and isoacids on milk fat depression: 2. Ruminal fermentation,fatty acid,and bacterial community structure

The experiment was conducted to understand ruminal effects of diet modification during moderate milk fat depression (MFD) and ruminal effects of 2-hydroxy-4-(methylthio)-butanoic acid (HMTBa) and isoacids on alleviating MFD. Five ruminally cannulated cows were used in a 5 × 5 Latin square design with the following 5 dietary treatments (dry matter basis): a high-forage and low-starch control diet with 1.5% safflower oil (HF-C); a low-forage and high-starch control diet with 1.5% safflower oil (LF-C); the LF-C diet supplemented with HMTBa (0.11%; 28 g/d; LF-HMTBa); the LF-C diet supplemented with isoacids [(IA) 0.24%; 60 g/d; LF-IA]; and the LF-C diet supplemented with HMTBa and IA (LF-COMB). The experiment consisted of 5 periods with 21 d per period (14-d diet adaptation and 7-d sampling). Ruminal samples were collected to determine fermentation characteristics (0, 1, 3, and 6 h after feeding), long-chain fatty acid (FA) profile (6 h after feeding), and bacterial community structure by analyzing 16S gene amplicon sequences (3 h after feeding). Data were analyzed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC) in a Latin square design. Preplanned comparisons between HF-C and LF-C were conducted, and the main effects of HMTBa and IA and their interaction within the LF diets were examined. The LF-C diet decreased ruminal pH and the ratio of acetate to propionate, with no major changes detected in ruminal FA profile compared with HF-C. The α-diversity for LF-C was lower compared with HF-C, and β-diversity also differed between LF-C and HF-C. The relative abundance of bacterial phyla and genera associated indirectly with fiber degradation was influenced by LF-C versus HF-C. As the main effect of HMTBa within the LF diets, HMTBa increased the ratio of acetate to propionate and butyrate molar proportion. Ruminal saturated FA were increased and unsaturated FA concentration were decreased by HMTBa, with minimal changes detected in ruminal bacterial diversity and community. As the main effect of IA, IA supplementation increased ruminal concentration of all branched-chain volatile FA and valerate and increased the percentage of trans-10 C18 isomers in total FA. In addition, α-diversity and the number of functional features were increased for IA. Changes in the abundances of bacterial phyla and genera were minimal for IA. Interactions between HMTBa and IA were observed for ruminal variables and some bacterial taxa abundances. In conclusion, increasing diet fermentability (LF-C vs. HF-C) influenced rumen fermentation and bacterial community structure without major changes in FA profile. Supplementation of HMTBa increased biohydrogenation capacity, and supplemental IA increased bacterial diversity, possibly alleviating MFD. The combination of HMTBa and IA had no associative effects in the rumen and need further studies to understand the interactive mechanism.     

19种不同产地核桃的营养成分及脂肪酸的分析比较研究

采用国家标准法,对广西和云南地区产的19种核桃样品进行果品质量、水分、灰分、总蛋白质、总脂肪、脂肪酸等各成分的含量进行测定分析。19种核桃样品的理化成分分析表明水分、灰分、蛋白质的含量均与其文献报道和国标规定的范围相符;除南丹中堡外,各品种的脂肪酸含量均大于65%,凤山顶猫最高。样品间出仁率的差异较为明显,凤山顶猫和云新核桃的总出油率最高。凤山顶猫的不饱和脂肪酸含量最高,金城紫的单一不饱和脂肪酸含量最高,云新核桃的多价不饱和脂肪最高。以核桃全果换算分析可知,不饱和脂肪酸含量在前三的品种为月里巴峨、凤山顶猫和云新;多价不饱和脂肪酸前三为云新、南丹中堡和凤山顶猫。ω6/ω3最低的前三位的样品为娘青、漾杂光明和龙佳。无论从核桃仁的脂肪酸含量分析排位,或核桃全果的脂肪酸含量分析排位,或是以ω6/ω3结合脂肪酸类型进行分析,均可作为筛选优良核桃品种的依据,可为广西和云南产核桃品种的筛选研究提供参考。     

Effects of diet fermentability and supplementation of 2-hydroxy-4-(methylthio)-butanoic acid and isoacids on milk fat depression: 1. Production,milk fatty acid profile,and nutrient digestibility

The objectives of this experiment were to determine the effects of increased diet fermentability and polyunsaturated fatty acids (FA) with or without supplemental 2-hydroxy-4-(methylthio)-butanoic acid (HMTBa), isoacids (IA; isobutyrate, 2-methylbutyrate, isovalerate, and valerate) or the combination of these on milk fat depression (MFD). Ten Holstein cows (194 ± 58 DIM, 691 ± 69 kg BW, 28 ± 5 kg milk yield) were used in a replicated 5 × 5 Latin square design. Treatments included a high-forage control diet (HF-C), a low-forage control diet (LF-C) causing MFD by increasing starch and decreasing neutral detergent fiber (NDF), the LF-C diet supplemented with HMTBa at 0.11% (28 g/d), the LF-C diet supplemented with IA at 0.24% of dietary dry matter (60 g/d), and the LF-C diet supplemented with HMTBa and IA. Preplanned contrasts were used to compare HF-C versus LF-C and to examine the main effects of HMTBa or IA and their interactions within the LF diets. Dry matter intake was greater for LF-C versus HF-C, but milk yield remained unchanged. The LF-C diet decreased milk fat yield (0.87 vs. 0.98 kg/d) but increased protein yield compared with HF-C. As a result, energy-corrected milk was lower (28.5 vs. 29.6 kg/d) for LF-C versus HF-C. Although the concentration of total de novo synthesized FA in milk fat was not affected, some short- and medium-chain FA were lower for LF-C versus HF-C, but the concentrations of C18 trans-10 isomers were not different. Total-tract NDF apparent digestibility was numerically lower (42.4 vs. 45.6%) for LF-C versus HF-C. As the main effects, the decrease in milk fat yield observed in LF-C was alleviated by supplementation of HMTBa through increasing milk yield without altering milk fat content and by IA through increasing milk fat content without altering milk yield so that HMTBa or IA, as the main effects, increased milk fat yield within the LF diets. However, interactions for milk fat yield and ECM were observed between HMTBa and IA, suggesting no additive effect when used in combination. Minimal changes were found on milk FA profile when HMTBa was provided. However, de novo synthesized FA increased for IA supplementation. We detected no main effect of HMTBa, IA, and interaction between those on total-tract NDF digestibility. In conclusion, the addition of HMTBa and IA to a low-forage and high-starch diet alleviated moderate MFD. Although the mechanism by which MFD was alleviated was different between HMTBa and IA, no additive effects of the combination were observed on milk fat yield and ECM.     

Influence of dietary oils and protein level on pork quality. 2. Effects on properties of fat and processing characteristics of bacon and frankfurter-style sausages

Palm kernel oil (PKO) and palm oil (PO) are used in tropical countries as cheaper substitutes for conventional feed sources such as soya bean oil (SBO) but little is known about their effects on meat quality. This study, therefore, evaluated the effects of these three dietary oils on the fatty acid composition (FA) of pork fat and the qualities of belly bacon and frankfurter sausage. The 3×2 factorial design also included high and low dietary protein. Total cooking loss, water loss and fat losses were determined in frankfurter sausages at chopping temperatures from 2 to 24°C. PKO resulted in a poor P:S ratio (0.34) and a relatively hard fat (slip point 32.8°C), but resulted in bacon with a higher tensile cohesive force and more high quality slices, judged subjectively. PO had a fatty acid composition closer to the SBO control, a better P:S ratio than PKO (0.48) and softer fat. There was a trend for total cooking losses and fat losses to be higher in PKO compared with PO and SBO at all chopping temperatures, suggesting that the firmest, most saturated fat (PKO) was least suitable for frankfurter production. The low protein diet increased the concentration of saturated fatty acids and increased fat firmness but its effect on fatty acid composition and other properties were less marked than those of oil type.     

Nutritional profile of restructured beef steak with added walnuts

Amino acid, fatty acid profile, cholesterol, vitamin E and mineral contents were assessed in restructured beef steak with 20% added walnut (20W). Compared with control restructured beef steak (0% added walnut), the product with added walnut presented a lower (P < 0.05) lysine/arginine ratio, larger (P < 0.05) quantities (mg/100 g product) of monounsaturated (MUFA) and n3 polyunsaturated (PUFA) fatty acids (mainly -linolenic acid), a lower (P < 0.05) n6/n3 PUFA ratio and a higher (P < 0.05) polyunsaturated/saturated fatty acid ratio. The replacement of raw meat material by walnut reduced (P < 0.05) the cholesterol content and increased (more than 400 times) the amount of γ-tocopherol. Iron, calcium, magnesium and manganese contents of 20W sample were greater (P < 0.05) than in the control. Some changes induced by added walnut in the nutritional quality of the restructured product may present health benefits.     

不同工艺制备核桃油品质比较及相关性分析

对溶剂提取、低温压榨两种方法提取的核桃油感官品质(色泽)、理化营养品质(水分及挥发物含量、脂肪酸组成、VE异构体含量、植物甾醇各组分含量)及加工品质(诱导时间、过氧化值、酸值、脂肪酸比例模式)进行测定并对其品质指标进行相关性分析。结果表明:低温压榨核桃油的加工品质较好,其诱导时间(1.92 h)较长,过氧化值(1.44 mmol/kg)和酸值(KOH)(0.69 mg/g)较低,且O/L(0.33)较高;其油酸含量(19.97%)及UFA含量(90.96%)较高,营养品质相对较好。色泽与诱导时间呈极显著正相关;油酸含量与亚油酸含量呈极显著负相关(r=-0.944);油酸、亚油酸、MUFA、PUFA、O/L与诱导时间的相关关系均达到极显著水平。     

The influence of breed and mh-genotype on carcass conformation, meat physico-chemical characteristics, and the fatty acid profile of muscle from yearling bulls

The influence of breed and mh-genotype on carcass conformation, meat physico-chemical characteristics and the fatty acid profile of muscle were studied. Samples from 16 yearling bulls from “Asturiana de los Valles” (AV, n = 12) and “Asturiana de la Montaña” (AM, n = 4) were collected. AV animals were classified into three groups according to the presence of the gene causing double-muscling (AV double-muscled (mh/mh), n = 4; AV heterozygous (mh/+), n = 4; AV normal (+/+), n = 4). Double-muscled animals displayed better carcass traits, lower total fat (comprised of subcutaneous (SC), intermuscular (IT) and intramuscular (IM) deposits), higher lean, moisture and drip loss, and lighter meat than AV normal animals. Heterozygous animals showed intermediate characteristics. AM animals, being a more rustic and smaller breed, showed lower conformation, higher total fat (SC, IT and IM), lower moisture and darker meat. According to the intramuscular fatty acid profile, mh/mh animals showed a lower proportion of SFA and MUFA, and a higher proportion of PUFA with an equal proportion of CLA in total fatty acid content. The P/S ratio increased with increasing number of mh alleles (or double-muscling character), while no differences between animal groups were found for the n − 6/n − 3 ratio.     

Formulation,invitro digestive study,and comparative fatty acid analysis of walnut oil-based infant formula,with human milk,animal milk,and commercial infant formula

Fatty acids content in walnut oil was investigated and compared with human milk, infant formula (IF) and animal milk (AM), then subjected to in-vitro digestion. Walnut oil (80.04 mg/g) and Human milk (73.11 mg/g) were comprised of unsaturated fatty acids, while AM (52.23 mg/g) and IF (40.50 mg/g) were significantly lower in unsaturated fatty acids. Confocal micrographs and particle size showed complete digestion of walnut oil-based infant formula (IFW) than AM and IF. Total fatty acid released during in-vitro digestion in different samples was IFW (2563.26 μmol/g fat), HM (2420.38 μmol/g fat), AM (1863.70 μmol/g), and in IF (3001.20 μmol/g). In IFW and HM, C18:2n6c was the highest single fatty acid released, with 47% and 40%, respectively, which was substantially different from AM and IF. Our research findings might help design an infant formula closer to human milk.     

The effect of dietary fiber level on milk fat concentration and fatty acid profile of cows fed diets containing low levels of polyunsaturated fatty acids

The objective of this study was to investigate the effect of dietary fiber level on milk fat concentration, yield, and fatty acid (FA) profile of cows fed diets low in polyunsaturated fatty acid (PUFA). Six rumen-fistulated Holstein dairy cows (639 ± 51 kg of body weight) were used in the study. Cows were randomly assigned to 1 of 2 dietary treatments, a high fiber (HF; % of dry matter, 40% corn silage, 27% alfalfa silage, 7% alfalfa hay, 18% protein supplement, 4% ground corn, and 4% wheat bran) or a low fiber (LF; % of dry matter, 31% corn silage, 20% alfalfa silage, 5% alfalfa hay, 15% protein supplement, 19% ground wheat, and 10% ground barley) total mixed ration. The diets contained similar levels of PUFA. The experiment was conducted over a period of 4 wk. Ruminal pH was continuously recorded and milk samples were collected 3 times a week. Milk yield and dry matter intake were recorded daily. The rumen fluid in cows receiving the LF diet was below pH 5.6 for a longer duration than in cows receiving the HF diet (357 vs. 103 min/d). Neither diet nor diet by week interaction had an effect on milk yield (kg/d), milk fat concentration and yield, or milk protein concentration and yield. During wk 4, milk fat concentration and milk fat yield were high and not different between treatments (4.30% and 1.36 kg/d for the HF treatment and 4.31% and 1.33 kg/d for the LF treatment, respectively). Cows receiving the LF diet had greater milk concentrations (g/100 g of FA) of 7:0; 9:0; 10:0; 11:0; 12:0; 12:1; 13:0; 15:0; linoleic acid; FA <C16; and PUFA; and lower concentrations of iso 15:0; 18:0; trans-9 18:1; cis-9, trans-11 conjugated linoleic acid (CLA); trans-9, cis-12 18:2; 20:0; and cis-9 20:1 compared with cows receiving the HF diet. Milk concentrations (g/100 g of FA) of total trans 18:1; trans-10 18:1; trans-11 18:1; trans-10, cis-12 CLA, and trans-9, cis-11 CLA were not different between treatments. The study demonstrated that cows fed a diet low in fiber and low in PUFA may exhibit subacute ruminal acidosis and moderate changes to milk fatty acid profile but without concomitant milk fat depression. The changes in FA profile may be useful for the diagnosis of SARA even in the absence of milk fat depression.     

坚果中脂肪含量及脂肪酸组成分析

目的分析16种市售坚果中脂肪含量及脂肪酸组成,比较不同品种坚果间脂肪含量、饱和脂肪酸和不饱和脂肪酸组成的差异。方法采用气相色谱分析法测定坚果中37种脂肪酸的含量,用最小显著性差异法(least-significant difference,LSD)法进行多重比较。结果坚果的平均脂肪含量为(55.6±0.86)g/100 g,变化范围为40.2~71.3 g/100 g,碧根果脂肪含量显著高于其他品种坚果脂肪含量(P0.05);坚果中的不饱和脂肪酸含量为72.77~95.47 g/100 g脂肪,平均值为(86.68±0.12)g/100 g脂肪,显著高于饱和脂肪酸4.53~22.19 g/100 g脂肪,平均值为(11.31±0.16)g/100 g脂肪(P0.05),东北榛子中单不饱和脂肪酸总含量最高,为84.34 g/100 g脂肪,而纸皮核桃中的多不饱和脂肪酸总含量最高,为74.17 g/100 g;坚果中不含短链脂肪酸和中链脂肪酸。结论坚果中不饱和脂肪酸含量较多,富含ω-6和ω-3脂肪酸,营养价值较高。     

不同贮藏条件下核桃及其油脂品质的变化分析

研究了不同贮藏条件对核桃及其油脂品质的影响。将新鲜核桃分别贮藏于常温、低温、蜡封与保鲜袋包装中,通过测定核桃水分含量、粗蛋白质含量、粗脂肪含量、脂肪酶活力以及核桃油酸值、过氧化值、脂肪酸组成,分析不同贮藏条件对核桃及其油脂品质的影响。结果表明:核桃油中饱和脂肪酸约占9%,不饱和脂肪酸含量高达约91%;蜡封贮藏条件下的核桃在贮藏90 d后,水分含量、粗蛋白质含量、粗脂肪含量下降速率最慢,分别减少8.09、0.7、2.16个百分点,核桃油酸值(KOH)与过氧化值增长速率较慢,分别为0.44 mg/g、2.19 meq/kg;蜡封贮藏条件下核桃脂肪酶活力先上升后下降,且整体活性较低;蜡封贮藏条件下核桃油中不饱和脂肪酸含量下降幅度最低,为1.03个百分点。在降低温度的基础上采用蜡封的密封方式,能够一定程度上隔绝氧气,对核桃及其油脂的保存有积极意义。     

Composition and estimation of intramuscular and subcutaneous fatty acid composition in Spanish young bulls

Sixty Pirenaica yearling intact bulls were raised and slaughtered at 519±50kg live weight and 371±18 days of age. Fatty acid composition of intramuscular lipids in longissimus dorsi muscle and subcutaneous fat were determined by capillary gas chromatography. Carcass conformation and fatness, carcass weight, ether extractable intramuscular fat percentage, marbling, dorsal fat thickness, and ultrasonic parameters were recorded to study the relationship between these traits and fatty acid profile. Lipids of subcutaneous adipose tissue had higher monounsaturated fatty acids (MUFA) percentage (49% vs. 33%) but lower saturated fatty acids (SFA) (51% vs. 46%) and polyunsaturated fatty acids (PUFA) (16% vs. 5%) percentages than intramuscular fat depots (p<0.001). Fatter carcasses had higher MUFA percentage and lower PUFA percentage (p<0.01) in intramuscular fat. Carcass weight and conformation would contribute to explain the fatty acid profile of subcutaneous fat (p<0.05). Ultrasound readings reflected the effect of fatness on fat composition.     

基于多元化学计量法的核桃仁炮制前后品质评价

目的 比较不同产地核桃仁炒制前后的品质差异.方法 收集我国7个核桃主产区的核桃样品,进行外观性状评价,并采用清炒法制备生、炒核桃仁.参照国家标准方法测定核桃仁的水分、灰分、粗脂肪和粗蛋白含量,采用气相色谱-质谱法测定脂肪酸组成,采用主成分分析和聚类分析等方法综合评价其品质差异性.结果 生品中水分含量为3.89％～5.0...     

Effect of preinoculation growth media and fat levels on thermal inactivation of a serotype 4b strain of Listeria monocytogenes in frankfurter slurries

Preinoculation growth conditions and fat levels were evaluated for effects on the heat resistance of Listeria monocytogenes strain MFS 102 in formulated frankfurter slurries and on frankfurter surfaces. Comparison of linear inactivation rates (D-values) for cells heated in frankfurter slurry showed that growth conditions were significant (P<0.05) factors affecting subsequent thermal resistance. The average D(60 degrees C)-values for the five preinoculation growth media tested from most resistant to least heat resistant were: tryptic soy broth with 0.6% yeast extract (TSBYE) (2.2 min) and 8.5% fat slurry (2.2 min), followed by 23% fat slurry (1.7 min) and 11% fat slurry (1.7 min), and then TSYBE with quaternary ammonium compounds added (TSBYE+Q) (1 min). The fat level in the frankfurter heating media also had a significant (P<0.05) effect on the thermal death rate of L. monocytogenes. Cells heated in 8.5% fat slurry had a significantly higher (P<0.05) D(60 degrees C)-value (2.2 min) than those heated in 11% fat (1.0 min) and 23% fat slurry (0.9 min). Growth media (TSBYE, 8.5% fat slurry, and TSBYE+Q), and fat level (15% and 20%), however, were not significant factors (P>0.05) affecting thermal inactivation rates on frankfurter surfaces. Heat inactivation rates were consistently higher on frankfurter surfaces compared to similar treatments done in frankfurter slurry. On frankfurter surfaces, a 2.3- to 5.1-log(10) reduction was achieved after 15 min depending on frankfurter surface type. The time necessary to achieve a 3-log(10) reduction using post-processing pasteurization of frankfurters in a hot water-bath at 60 degrees C almost doubled for cells grown in TSBYE and heated in 23% fat frankfurter slurry (19.6 min) versus cells grown and heated in 8.5% fat frankfurter slurry (10.8 min).     

Carcass and meat quality characteristics and fatty acid composition of tissues from Pietrain-crossed barrows and gilts fed an elevated monounsaturated fat diet

Fifty-one (Landrace∗Large White)∗Pietrain barrows and gilts were used to compare the effect of a diet rich in oleic acid (HO) by feeding a by-product of the olive industry (Greedy-Grass OLIVA®: 1.4% growing, 3.8% finishing) or a grain and soy diet (CONTROL) on carcass characteristics, meat quality and fatty acid profile of intramuscular and subcutaneous fat. Gilts had leaner (P < 0.05) carcasses with lower fat percentage in major primal cuts, and less (P < 0.05) saturated fat compared with barrows with no interaction (P > 0.05) between dietary treatment and gender. Source of dietary fat had no effect (P > 0.05) on primal cut yields, composition of major primal cuts, or carcass and meat quality characteristics. Intramuscular fat from HO fed pigs had higher (P < 0.05) percentage of saturated (SFA) and monounsaturated (MUFA) fatty acids, and lower (P < 0.05) polyunsaturated fatty acids (PUFA) and n-6:n-3 ratio compared with CONTROL animals (37.4% vs. 36.8%, 44.7% vs. 40.1%, 17.9% vs. 23.2%, and 18.9 vs. 21.8 ratio, respectively). Subcutaneous fat from pigs fed HO had greater (P < 0.05) MUFA percentage, lower (P < 0.05) SFA and PUFA percentage, and lower (P < 0.05) n-6:n-3 ratio than pigs fed CONTROL diet (51.4% vs. 48.0%, 30.5% vs. 32.9%, 18.1% vs. 20.1%, and 9.83 vs. 11.3 ratio, respectively). Intramuscular fat had higher proportion of SFA and lower of MUFA showing a higher degree of tissue saturation compared with subcutaneous fat. Feeding Greedy-Grass increased MUFA and decreased PUFA proportions in fat depots reducing the risk of production of carcasses that are soft and oily which result in lower technological and processing quality.     

水酶法联产核桃油和核桃多肽工艺优化及油脂脂肪酸分析

为提高核桃的综合利用率,优化了水酶法联产核桃油和核桃多肽的工艺条件,并分析了油脂的脂肪酸组成。通过比较4种不同的蛋白酶与纤维素酶复配对核桃提油率和多肽产量的影响,确定最佳酶组合;在此基础上,通过单因素和L₁₈（35）正交试验研究了pH、酶解温度、酶解时间、料液比和加酶量对核桃提油率以及多肽产量的影响,得出最佳工艺条件;利用气相色谱技术分析了核桃油的脂肪酸组成。结果表明,木瓜蛋白酶与纤维素酶复配（2:1,w/w）为最佳酶组合;水酶法制备核桃油和核桃多肽的最佳联产工艺条件为:加酶量3.0%,料液比1:5（g/mL）,pH5,时间3.0 h,温度60 ℃;在此工艺条件下,核桃提油率可达53.37%,多肽产量为4.01 mg/g。气相色谱测定结果表明,核桃油中共检测出5种脂肪酸,分别为亚油酸（62.26%）、油酸（18.64%）、α-亚麻酸（10.57%）、棕榈酸（6.00%）、硬脂酸（2.53%）;核桃油以不饱和脂肪酸为主,其总含量高达91.47%,其中多不饱和脂肪酸含量为72.83%,单不饱和脂肪酸含量为18.64%。该工艺可为水酶法联产核桃油和核桃多肽的产业化应用提供参考。     

Extensively reared Iberian pigs versus intensively reared white pigs for the manufacture of frankfurters

Physico-chemical characteristics and different quality traits of the raw material (meat and adipose tissue) and the frankfurters elaborated from extensively reared Iberian pigs (IF) and intensively reared white pigs (WF) were evaluated. Hybrid frankfurters (HF) made with meat from white pigs and adipose tissue from Iberian pigs were also studied. The differences found between muscles and adipose tissues from Iberian and white pigs largely influenced the characteristics displayed by the frankfurters. Particularly remarkable are the higher amounts of substances with proven antioxidant activity such as tocopherols and phenolic compounds in tissues from Iberian pigs than in those from white pigs. No significant differences were found amongst frankfurters for their proximate composition though IF presented a higher iron content than WF and HF. IF exhibited a redder and darker colour than WF and HF. The latter were paler and showed higher hue values than IF. Concerning their fatty acid composition, IF had higher proportions of oleic acid and MUFA and smaller proportions of SFA and PUFA than WF. From a nutritional point of view, IF had a lower n-6/n-3 value than WF. The addition of adipose tissue from Iberian pigs to the HF modified its fatty acid composition compared to that of WF, significantly increasing the percentages of MUFA and reducing the proportions of PUFA, SFA and the n-6/n-3 value. Though no significant differences were found amongst frankfurters for their texture profile, a clear trend was detected, with the HF showing intermediate texture characteristics between IF and WF.     

Effect of restricted feeding and realimentation periods on pork quality and fatty acid profile of M. longissimus thoracis

An experiment with 94 fattening pigs (48 gilts and 46 barrows) was conducted to determine the effect of feeding 25% restricted diets at different body weights on meat quality and fatty acid profile of M. longissimus thoracis (LT). During the 84 days of the experiment (4 periods, 21 days each), animals with an initial weight of about 31 kg were fed in different periods of observation ad libitum (A) or restricted diets (R) in groups AAAA, AARA, RAAA and RARA. After 21 days of the experiment, the restricted-fed pigs, compared to those fed ad libitum, had a lower total fat content of M. longissimus thoracis (P<0.05), higher shear force (P=0.068), and lower proportions of SFA (C14:0, C18:0 P<0.05) and MUFA and higher proportions of PUFA (C20:4, C22:4 P<0.05) in the fatty acid profile. Three weeks after the restricted feed supply was lifted, the total fat content in LT muscle was higher than in animals fed ad libitum throughout (2.34 vs. 2.02), very close after the next 3 weeks of realimentation (3.16 vs. 3.15) and lower after another 3 weeks (3.19 vs. 3.49). Regardless of the time at which restricted feeding was started and the number of restricted feeding periods, the total fat content in the LT muscle at the end of the experiment was similar or lower in groups RAAA, AARA and RARA, compared to group AAAA. The coefficient of correlation between the total fat content in LT and the shear force was -0.36 (P<0.01). Colour, pH and drip loss did not depend on the level of nutrition. After 84 days of observation, animals from groups RARA and AARA, compared to pigs from groups AAAA and RAAA, were characterized by a slightly higher shear force of LT, lower SFA and MUFA (P<0.001), and higher n-6 PUFA (P<0.01) and n-3 PUFA (P<0.01) proportions in the fatty acid profile. The fatty acid profiles of AAAA pigs and pigs undergoing a 63-day realimentation period (RAAA) were similar. Regardless of the feeding scheme, the n-6:n-3 ratio exceeded 10 in all the groups.