Infrared Spectroscopy-Based Chemometric Analysis for Lard Differentiation in Meat Samples

One of the most pressing concerns for the consumer market is the detection of adulteration in meat products due to their preciousness.The rapid and accurate identification mechanism for lard adulteration in meat products is highly necessary,for developing a mechanism trusted by consumers and that can be used to make a definitive diagnosis.Fourier Transform Infrared Spectroscopy(FTIR)is used in this work to identify lard adulteration in cow,lamb,and chicken samples.A simplified extraction method was implied to obtain the lipids from pure and adulterated meat.Adulterated samples were obtained by mixing lard with chicken,lamb,and beef with different concentrations(10%–50%v/v).Principal component analysis(PCA)and partial least square(PLS)were used to develop a calibration model at 800–3500 cm^(−1).Three-dimension PCA was successfully used by dividing the spectrum in three regions to classify lard meat adulteration in chicken,lamb,and beef samples.The corresponding FTIR peaks for the lard have been observed at 1159.6,1743.4,2853.1,and 2922.5 cm−1,which differentiate chicken,lamb,and beef samples.The wavenumbers offer the highest determination coefficient R2 value of 0.846 and lowest root mean square error of calibration(RMSEC)and root mean square error prediction(RMSEP)with an accuracy of 84.6%.Even the tiniest fat adulteration up to 10%can be reliably discovered using this methodology.

Optimization and kinetic modeling of waste lard methanolysis in a continuous reciprocating plate reactor

Continuous biodiesel production from a waste pig-roasting lard,methanol and KOH was carried out in a reciprocating plate reactor(RPR)using a factorial design containing three process factors,namely methanol/lard molar ratio,catalyst loading,and normalized height of the reactor.The main goals were to optimize the influential process factors with respect to biodiesel purity using the response surface methodology and to model the kinetics of the transesterification reaction in order to describe the change of triacylglycerols(TAG)and fatty acid methyl esters(FAME)concentrations along the RPR height.The first-order rate law was proved for both the reaction and the mass transfer.The model of the changing reaction mechanism and mass transfer of TAG was also applicable.Both kinetic models agreed with the experimental concentrations of TAG and FAME determined along the RPR height.

High-Lard and High-Fish Oil Diets Differ in Their Effects on Insulin Resistance Development, Mitochondrial Morphology and Dynamic Behaviour in Rat Skeletal Muscle

Fish oil (mainly omega 3 polyunsaturated fatty acids), differently from lard (mainly saturated fatty acids) has been suggested to have anti-inflammatory effects associated with amelioration of insulin sensibility. An important role in skeletal muscle insulin resistance development has been recently attributed to mitochondrial dynamic behavior. Mitochondria are dynamic organelles that frequently undergo fission/fusion processes and a shift toward fission process has been associated with skeletal muscle mitochondrial dysfunction and insulin resistance development. The present work aimed to evaluate if the replacement of lard with fish oil in high-fat diet positively affect skeletal muscle mitochondrial dynamic behavior in association with the improvement of insulin-resistance. Body weight gain, systemic insulin-resistance (glucose/insulin ratio), serum TNFα levels and skeletal muscle lipid content were assessed in rats fed a high-lard or high-fish-oil diet for 6 weeks. In skeletal muscle sections, immunohistochemical analysis were performed to detect the presence of insulin receptor substrate 1 (IRS1) and tyrosine phosphorylated IRS1 (key factor in insulin signalling pathway) as well as to detect the main proteins involved in mitochondrial fusion (MFN2 and OPA1) and fission (DRP1 and Fis1) processes. Skeletal muscle mitochondrial ultrastructural features were assessed by electron microscopy. High-fish oil feeding induced lower body weight gain, systemic inflammation and insulin-resistance development as well as skeletal muscle lipid accumulation compared to high-lard feeding. Skeletal muscle sections from high-fish oil fed rats exhibited a greater number of immunoreactive fibers for MFN2 and OPA1 proteins as well as weaker immunostaining for DRP1 and Fis1 compared to sections from high-lard fed rats. Electron microscopy observations suggested a prominent presence of fission events in L rats and fusion events in F rats. The positive effect of the replacement of lard with fish oil in high-fat diet on systemic and skeletal muscle insulin sensibility was associated to changes in mitochondrial dynamic behavior.

Effects of Lard Enriched with n-3 Polyunsaturated Fatty Acids on Serum Lipid Composition in Rats

This study evaluated the lard enriched with n-3 polyunsaturated fatty acids(PUFAs)on serum lipid composition in rats.The experiment contained two parts:(A)20 crossed pigs(Landrace×Min,60±2 kg)were assigned randomly into two dietary groups:a control group and a group fed the diet added 10%linseed based on the control diet.This part lasted 56 days and the results showed that the levels of the total n-3 PUFA in lard were improved approximately 2-fold(p<0.05),when pigs were fed 10% flaxseed compared to a control diet of corn.The lard taken from pigs was melted and preserved for rat experiment;(B)45 Sprague-Dawley rats at day 36 were randomly fed one of three diets for 42 days:the diet without added fat,the diet contained 10% common lard from pigs fed a conventional corn ration and the diet contained 10% lard enriched with n-3 PUFA from pigs fed 10% flaxseed.Rats fed lard significantly increased(p<0.05)serum cholesterol levels compared with rats maintained on a diet without lard.However,rats fed the lard enriched with n-3 PUFA significantly decreased the level of low-density lipoprotein cholesterol in serum(p<0.05)and better hepatic antioxidant defense capacities,when compared with rats fed common lard(p<0.05).The results showed that pigs fed diet with n-3 PUFA produced lard enriched with n-3 PUFA and thus provided positive health benefits to the consumers.

Moderate quantity of lard mixed with sunflower oil attenuate lipid accumulation in mice

Lard,a fat rich in saturated fatty acids(SFAs),is regarded as a risk factor for metabolic diseases.In the present study,effect of different lard blended with sunflower oil diets on lipid accumulation in adipose tissue,liver,and serum by mouse model was researched.Body weight,body fat percentage,cross-sectional area of adipocytes,liver triglycerides(TGs),and oil red stained area in mice liver of lard blend sunflower oil(L-SFO)group were significantly lower than those of sunflower oil(SFO)group,whereas no significant differences were observed between mice of lard and L-SFO groups.Serum TG and free fatty acid levels were significantly lower in L-SFO group than in other two groups.Furthermore,data showed that sunflower oil decreased contents of hormonesensitive lipase and carnitine palmitoyl transferase 1(CPT-1)and increased fatty acid synthase activity in liver tissue.A mixture of lard and sunflower oil rather than only sunflower oil or lard might promote body fat loss and reduce lipid accumulation in adipose tissue,serum,and liver by promoting hydrolysis of TG,increasingβ-oxidation of fatty acids.These data suggested that mixing lard and vegetable oil(e.g.sunflower oil)for cooking,or alternate using lard and vegetable oil could be beneficial for reducing body fat.

Effect of mixing lard with soybean oil in cooking on hepatic antioxidative ability and renal metabolic activity

A simulate daily oriental dietary pattern(a blend of lard and soybean oil)was performed in this research to investigate influence on liver and kidney function.Sixty mice were randomly divided into 6 groups with diets of different fat added oils respectively for 12 weeks.Malondialdehyde and uric acid contents in mice fed with blended oil were significantly lower than in those fed only with soybean oil and lard due to the improved activities of antioxidant enzymes.Daily use of a blend of lard with soybean oil significantly increased antioxidant capacity,reduced lipid peroxidation of liver and serum uric acid production,thus protected liver and renal function.It also suggests that the oriental dietary pattern might reduce the risk of gout.

Graphene-and Multi-Walled Carbon Nanotubes-Coated Tapered Plastic Optical Fiber for Detection of Lard Adulteration in Olive Oil

A rapid and high-performance sensor for lard adulterant in edible oil was developed using the tapered plastic optical fiber(POF)coated with graphene and multi-walled carbon nanotubes.The coating material was deposited onto a tapered POF with a taper waist diameter and a taper length of 0.45 mm and 1 cm,respectively.The addition of the coating material was used to increase the sensitivity and selectivity coefficient of the tapered POF toward the lard substance.The sensing mechanism is based on a simultaneous interaction of lard substance and an evanescent wave of tapered POF with the coating layers.The results showed that graphene coating on the tapered POF increased the selectivity coefficient of the tapered POF towards lard substance from 33.54 to 324.19,and it gave a sensitivity of 0.427 dBm/%.In comparison,multi-walled carbon nanotubes coating increased the selectivity coefficient to 71.65 and increased its sensitivity to 1.189 dBm/%.Thus,the proposed configuration of the tapered POF with the coating material offered a simple configuration for a rapid,high sensitivity and selectivity detection of lard adulterant in edible oils.

加热温度对猪油甘油二酯理化特性及风味的影响

为研究3种加热温度(95、120、145℃)对猪油甘油二酯(diacylglycerol,DAG)理化特性及风味的影响,测定猪油DAG的傅里叶变换红外光谱、融化和结晶特性、晶型、流变特性、热重、脂肪酸组成和挥发性组分等指标。结果表明:随温度升高,猪油DAG晶型由β’向β型转化;傅里叶变换红外光谱显示,加热改变了DAG的官能团分布;流变特性及热重分析表明,随温度升高,猪油DAG黏度增大、热稳定性降低;醛类、醇类等挥发性风味物质随温度升高逐渐增多、不饱和脂肪酸含量先上升后降低。不同加热温度对DAG理化特性及风味产生影响,120℃是猪油DAG较适宜的热加工温度。

流媒体服务中基于间隔缓存的LARD调度算法

以往对提高流媒体服务器集群服务能力的研究仅局限于请求调度或者缓存策略上,很少考虑到两者之间的相互作用。针对当前流媒体服务中,存储系统的磁盘I/O带宽已成为制约流媒体服务集群服务能力的瓶颈之一,将基于位置感知的LARD调度策略与间隔缓存策略相结合,应用于流媒体服务,有效地提高了流媒体请求的缓存利用率,由此节省了访问存储系统的磁盘I/O带宽,达到提高流媒体服务集群服务能力的目的。实验证明,在高请求到达率的情况下,采用新策略后流媒体服务集群的服务能力得到了提高。

没食子酸丙酯对猪油的抗氧化效果研究

目的研究不同浓度的没食子酸丙酯(propyl gallate,PG)对猪油抗氧化效果的影响。方法以酸价(acid value,AV)、过氧化值(peroxide value,PV)、茴香胺值(ρ-anisidine value,ρ-AnV)、1,1-二苯代苦基苯肼(1,1-diphenyl-2-picryl-hydrazyl,DPPH)自由基清除能力和脂肪酸组成为指标,采用Schaal法检测猪油抗氧化性能,结合Rancimat法测得高温下的氧化稳定性指数(oxidation stability index,OSI),比较了不同浓度(0.02、0.04、0.06、0.08、0.10g/kg)的PG对猪油的抗氧化效果,通过主成分分析得出PG在猪油中应用的最佳浓度。结果PG能够有效延缓猪油各项氧化基础指标的升高,且对其脂肪酸组成无显著影响(P>0.05),可作为一种安全高效的抗氧化剂应用于猪油中。主成分分析结果表明,添加0.10g/kg为PG在猪油中应用的最佳浓度,其AV(1.83 mg/g)和PV(1.30 g/100 g)在Schaal烘箱实验15 d后最低,ρ-AnV为18.33,DPPH自由基清除能力为12.44μmol TE/kg,OSI为0.96 h,抗氧化保护系数为1.45。结论PG可有效提高猪油的氧化稳定性,浓度对PG在猪油中的抗氧化效果有影响,其中浓度在0.10g/kg时效果最佳。本研究可为PG在动物油中的应用提供指导依据,具有重要的理论和应用价值。

猪脂肪控制氧化及挥发性氧化产物研究

通过单因素试验和正交试验研究以热反应制备肉味香精前体物为目的的猪脂肪控制氧化工艺条件。以过氧化值(POV)、硫代巴比妥酸值(TBA)和酸值(AV)表征油脂的氧化状态。结果表明,猪脂肪控制氧化的较佳工艺条件为:反应温度120℃、反应时间2h、氧气流速0.025m3/h。采用固相微萃取-气质联用技术对猪脂肪控制氧化产物中的挥发性成分进行分析,共鉴定出32种化合物,其中醛类化合物占52.52%,为猪脂肪控制氧化产物中的主要挥发性成分。

蜂胶抗氧化作用研究

本文以猪油、核桃仁和色拉酱等富含油脂食品为底物研究了蜂胶的抗氧化作用。结果表明蜂胶能明显延缓这些底物氧化酸败 ,其抗氧化活性优于同剂量的BHT和PG ,且维生素C。

猪油控制氧化的工艺研究

通过正交实验和单因素实验对以制备肉味香精为目的的猪油控制氧化工艺进行了优化 ,并对猪油控制氧化的规律进行了探讨。实验结果表明 ,猪油控制氧化的较优化工艺条件是 :反应温度 130℃ ,反应时间 4h ,空气流速 0 .0 12m3/(h·10 0g猪油) ;较合适的氧化状态为 :POV 2 70～ 4 0 0meq/kg ,p -AV大于 2 0 0 ,AV小于 4 .0mgKOH/g ,在此状态下氧化猪油经热反应可获得肉香前体物和肉香风味。

辣椒籽提取物对猪油抗氧化作用研究

用不同溶剂提取辣椒籽中的抗氧化物质 ,采用碘量法研究辣椒籽提取物对猪油的抗氧化作用。结果表明 ,辣椒籽提取物对猪油的氧化均有明显的抑制作用。不同溶剂提取和不同品种的辣椒籽提取物的抗氧化作用效果不同。其中 ,脱脂甲醇提取物 >甲醇提取物 >脱脂水提取物 >石油醚提取物 ;花溪辣椒品种 >

苜蓿黄酮抗氧化性研究

将紫花苜蓿黄酮粗提物以0.02%,0.05%,0.2%,0.5%,1%的比例加入到猪油中,70℃恒温保藏,定期取样用Na2S2O3-I2滴定法测定POV值,并与0.02%BHT、0.05%VC的抗氧化效果进行比较。结果表明:添加苜蓿黄酮粗提物对猪油具有良好的抗氧化作用,其中以添加0.2%者抗氧化效果最佳,但不如BHT和VC效果好;另外VC和VE等对苜蓿黄酮粗提物具有明显的协同抗氧化作用,效果优于单独添加0.2%黄酮粗提物和VC、BHT。

蓝莓花色苷提取物抗油脂氧化能力的研究

以乙醇为溶剂从圣云蓝莓果中提取得到蓝莓花色苷。研究蓝莓花色苷对猪油和脂质体的抗氧化活性。结果表明蓝莓花色苷对猪油具有较强的抗氧化,且具有剂量效应关系,以添加0.4%精制花色苷抗氧化效果最佳,但不如BHT效果好;另外抗坏血酸等对蓝莓花色苷具有明显的协同抗氧化作用。蓝莓花色苷对脂质体过氧化有显著的抑制作用,并且高于抗坏血酸对脂质体过氧化的抑制作用,精制蓝莓花色苷的IC50为165.97μg/mL,粗蓝莓花色苷的IC50为278.16μg/mL。

高效液相色谱法测定猪油甘油三酯中的脂肪酸位置分布

建立了一种采用高效液相色谱法(HPLC)分析猪油甘油三酯中的脂肪酸组成及其位置分布的方法。利用sn 1,3位专一性脂肪酶对甘油三酯sn 1,3位上的脂肪酸进行水解,形成sn 2位甘油单酯和游离脂肪酸;之后,通过甘油三酯中脂肪酸总含量和sn 1,3位上脂肪酸含量之间的差值计算出sn 2位上的脂肪酸含量。利用 2 溴苯乙酮仅同游离脂肪酸作用的特点,将脂肪酸酯化为苯乙酰甲酯,然后进行HPLC分析。分析所用色谱柱为ZORBAXSBC18柱,以十七酸作为内标,甲醇 乙腈 水为流动相,采用梯度洗脱 (梯度洗脱程序为甲醇 乙腈 水由 80∶10∶10(体积比,下同)在 35min内线性变化到 86∶10∶4,然后在 5min内恢复到起始比例,流动相流速为 1mL/min),通过测定苯乙酰甲酯在 254nm处的吸光度值来测定脂肪酸含量。结果表明,猪油甘油三酯中的脂肪酸主要是棕榈酸和油酸(分别占总量的 26 61%和 43 18% ),其中油酸主要分布于sn 1,3位上,而棕榈酸分布于sn 2位上。这些测定结果与传统气相色谱法的测定结果相吻合。该方法简单可行,省去了传统测定中费时的薄层色谱分离步骤,可成为一种有效的实验室分析方法。

无梗五加果黄酮的提取及抗油脂氧化性能的研究

以无梗五加的果实为原料,采用乙醇回流法提取黄酮,采用烘箱法高温诱导猪油发生过氧化反应,以研究粗黄酮对油脂的抗氧化性。结果表明:乙醇回流提取无梗五加果黄酮的最佳工艺为:50%乙醇、料液比1:80、提取时间4小时、提取1次。从无梗五加中提取的粗黄酮对猪油有明显的抗氧化作用。

猪油酸解制备人乳脂替代品的研究

猪油Sn-2位富含棕榈酸,是制备人乳脂替代品很好的原料。以猪油和植物油脂肪酸混合物为底物,Lipozyme RM IM酶为催化剂进行酸解反应制备人乳脂替代品。实验确定最佳条件为:猪油与混合脂肪酸质量比为1∶1.5,加酶量为底物质量的5%,反应温度60℃,反应时间1.5 h,反应后得到总脂肪酸组成及Sn-2位脂肪酸组成类似于人乳的乳脂替代品。