宣威火腿与金华火腿中游离脂肪酸组成比较分析

以两年宣威火腿和金华火腿为对象,采用气相色谱-质谱联用法(GC-MS)分别对宣威火腿和金华火腿的皮下和肌内脂肪中游离脂肪酸的组成进行分析。结果表明:宣威火腿和金华火腿的肌内脂肪和皮下脂肪中均检测出22种游离脂肪酸,含量较高的脂肪酸为棕榈酸(C16:0)、硬脂酸(C18:0)、油酸(C18:1n9c)与亚油酸(C18:2n6c),且不同火腿及不同部位间的脂肪酸组成含量存在明显差异;金华火腿肌内及皮下脂肪中总游离脂肪酸含量分别为29.24、102.68 μg/mg,分别比宣威火腿高34.58%(p<0.05)、29.09%(p>0.05);宣威火腿和金华火腿肌内脂肪中饱和脂肪酸含量高于不饱和脂肪酸含量,皮下脂肪中不饱和脂肪酸含量高于饱和脂肪酸含量。金华火腿肌内、皮下游离脂肪酸含量均高于宣威火腿相应部位游离脂肪酸含量。     

金华火腿中肌间脂肪和皮下脂肪的脂肪酸分析

提取成熟金华火腿中的肌间脂肪和皮下脂肪 ,分离并测定了其中甘油酯、磷脂和游离脂肪酸的含量 ,并对其脂肪酸组成进行了分析 ,结果表明 :肌间脂肪含量为 12. 4 % ,甘油酯、磷脂和游离脂肪酸分别占 77. 3%、11 .2 %和 10 . 9% ;皮下脂肪含量为 90 .7% ,相应的 3部分分别占 88.7%、0 . 2 %和 10 .4 %。肌间脂肪和皮下脂肪的脂肪酸都以C16:0 、C18:1、C18:2 为主要成分。甘油酯里单不饱和脂肪酸的含量都远远高于其在磷脂和游离脂肪酸中的含量 ,而磷脂里多不饱和脂肪酸的含量明显高于其在甘油酯和游离脂肪酸中的含量。     

GC-MS法测定宣威火腿中脂肪酸组成

以宣威火腿为对象,通过提取成熟宣威火腿的肌间脂肪和皮下脂肪,采用气相色谱-质谱联用法(GC-MS)对宣威火腿肌间脂肪与皮下脂肪中脂肪酸的组分进行探讨。结果表明:宣威火腿肌间脂肪中含11种饱和脂肪酸,占总脂肪酸的34.75%,15种不饱和脂肪酸,占总脂肪酸含量的64.78%,主要的脂肪酸为油酸(C18∶1)、棕榈酸(C16∶0)、硬脂酸(C18∶0)、亚油酸(C18∶2),含量分别为33.44%、23.37%、8.44%、20.55%;皮下脂肪中含11种饱和脂肪酸,占总脂肪酸的36.23%,15种不饱和脂肪酸,占总脂肪酸含量的63.47%,主要的脂肪酸为油酸(C18∶1)、棕榈酸(C16∶0)、硬脂酸(Cl8∶0)、亚油酸(C18∶2),含量分别为31.47%、21.90%、11.13%、22.39%。     

金华火腿中肌内脂肪的提取和脂肪酸分析研究

通过正交实验,确定金华火腿中肌内脂肪的最佳提取条件是:氯仿和甲醇(2:1,v/v)的用量为样品重量的14倍,振荡1.5h,取滤液加其1/2体积的1%NaCl溶液.处理60d的金华火腿中肌内脂肪的含量为12.4%,甘油酯、磷脂、游离脂肪酸分别占76.5%、18.8%、4.7%.甘油酯中单不饱和脂肪酸的含量最高,为47.89%;而磷脂中多不饱和脂肪酸的含量最高,为50.94%;游离脂肪酸中则含有较多的饱和脂肪酸(41.56%).甘油酯、磷脂和游离脂肪酸中都是以C16.0、C18:1、C18:2为主要成分.     

传统风鸭加工过程中脂肪水解和氧化的研究

以樱桃谷瘦肉鸭为原料,按传统工艺加工风鸭,分析了鸭胸肉及皮下脂肪的硫代巴比妥酸值(TBARS)、羰基双烯值、游离脂肪酸(FFA)含量在加工过程中的变化规律。结果表明,胸肉脂肪的TBARS值在于腌工艺阶段显著上升(P<0.05),在风干工艺阶段先降后升;而皮下脂肪的TBARS值持续增加,在风干最后阶段略有下降。胸肉脂肪和皮下脂肪的羰基双烯值在加工过程中均逐渐增加,最后有下降趋势。饱和脂肪酸(SSFA)和单不饱和脂肪酸(SMUFA)在加工过程中变化不大,而多不饱和脂肪酸(SPUFA)在腌制后有下降,后逐渐回升,在风干20 d达到最高。亚油酸、花生四烯酸、油酸和棕榈酸是游离脂肪酸的主体成分,不饱和脂肪酸占FFA总量的76%以上。     

五种云南火腿游离脂肪酸含量比较分析

采用气相色谱-质谱联用仪(GC-MS)对宣威火腿、诺邓火腿、鹤庆圆腿、撒坝火腿及三川火腿共5种云南干腌火腿肌内及皮下部位进行游离脂肪酸种类及含量比较分析。结果表明,5种火腿中的游离脂肪酸种类最多检测出16种,棕榈酸(C16∶0)、硬脂酸(C18∶0)、油酸(C18∶1 n-3)、和亚油酸(C18∶2)是5种云南火腿的主要脂肪酸,且不同火腿及不同部位间的脂肪酸组成及含量存在差异(P 0. 05);以诺邓火腿和三川火腿的含量最高,诺邓火腿肌内及皮下脂肪部分的游离脂肪酸总量分别为40. 378 mg/g、79. 959 mg/g,三川火腿的为42. 336 mg/g与77. 548 mg/g,其次分别为撒坝火腿(30. 147 mg/g、62. 049 mg/g),宣威火腿(28. 446 mg/g、62. 078 mg/g)与鹤庆圆腿(27. 361 mg/g、55. 953 mg/g);肌内及皮下的不饱和脂肪酸总含量与必需脂肪酸含量,诺邓火腿与三川火腿均高于其余火腿,因此诺邓火腿与三川火腿的脂肪组成较其他3种火腿更为合理。     

传统金华火腿加工过程中肌内脂肪的变化

分别提取0、32、60、160、240d的金华火腿中的肌内脂肪,分析其甘油酯、磷脂、游离脂肪酸的含量和脂肪酸组成。结果表明:磷脂的含量从23.3%减少到11.2%,游离脂肪酸的含量从1.6%增加到11.5%,甘油酯的含量没有发生显著性变化;甘油酯和磷脂中的饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)、多不饱和脂肪酸(PUFA)都无显著性变化;游离脂肪酸中,PUFA的含量显著减少,MUFA的含量减少,但其变化不显著,SFA的含量显著增加。     

腊肉加工过程中游离脂肪酸的变化研究

分别对腊肉加工过程中肥肉和瘦肉的游离脂肪酸(FFA)的变化进行了测定,结果表明:肥肉中主要的FFA为油酸(C18∶1)、硬脂酸(C18∶0)、棕榈酸(C16∶0)和亚麻酸(C18∶3),且总FFA不断积累,81h达到最大值;脂肪酸在肥肉中的释放速率为亚油酸>亚麻酸>硬脂酸>油酸>棕榈酸。瘦肉中主要的FFA为硬脂酸、棕榈酸、亚油酸(C18∶2)和油酸,总FFA也不断积累,43h达到最大值;脂肪酸在瘦肉中的释放速率为硬脂酸>亚油酸>棕榈酸>油酸。腊肉加工过程中,脂质发生的降解和氧化对形成腊肉特有的风味发挥了重要作用。     

金华火腿传统加工过程中的脂肪氧化研究

取0、30、62、160和240d的金华火腿,提取肌内脂肪和皮下脂肪,分别测定脂肪中各组分的含量和氧化指标。结果表明,肌内脂肪中磷脂含量较多,皮下脂肪中甘油酯含量较多;在金华火腿加工过程中,肌内脂肪和皮下脂肪的酸价一直上升,过氧化值、羰基价和TBA值有升有降,但总体呈上升趋势,脂肪氧化程度不断增强。同时发现,肌内脂肪比皮下脂肪的氧化程度更高。     

传统金华火腿加工过程中皮下脂肪的变化

分别提取0、32d、60d、160d、240d的金华火腿中的皮下脂肪,分析其甘油酯、磷脂、游离脂肪酸的含量和脂肪酸组成。结果表明:甘油酯的含量从95.7%减少到85.4%,游离脂肪酸的含量从2.1%增加到14.3%,磷脂的含量没有发生显著性变化;甘油酯中的SFA有显著性变化,MUFA和PUFA无显著性变化;磷脂中的SFA、MUFA和PUFA都没有显著性变化;游离脂肪酸中,PUFA的含量显著减少,MUFA的含量减少,但其变化不显著,SFA的含量显著增加。     

Fatty acid composition of adipose depots of suckling lambs raised under different production systems

Forty-nine male Talaverana-breed suckling lambs slaughtered at 14 kg live weight were used to study the fatty acid composition of adipose depots of lambs raised under different management systems (pasture or drylot) and diets (maternal milk with or without a concentrate supplement). Drylot lambs displayed a higher fatness score, in addition to greater dorsal fat thickness; these parameters corresponded with a greater percentage of total fat at dissection. Addition of concentrate to the diet did not modify carcass fatness. Drylot lambs presented higher proportions of oleic acid (C18:1) and monounsaturated fatty acids (MUFA) and lower linolenic acid (C18:3) values in subcutaneous and intramuscular fat (muscle longissimus thoracis). The subcutaneous fat of these lambs thus displayed a higher n-6/n-3 PUFA ratio (C18:2/C18:3) than that of pasture-raised ones. Concentrate in the diet of both pasture and drylot lambs resulted in higher linoleic fatty acid (C18:2) and PUFA values and a greater PUFA/SFA ratio in intramuscular fat than the corresponding values of lambs which consumed maternal milk alone. Loin displayed a higher percentage of subcutaneous and intramuscular chemical fat than leg. Compared with intramuscular leg fat (muscle quadriceps femoris), intramuscular loin fat (muscle longissimus thoracis) had lower oleic acid (C18:1) and MUFA values, higher PUFA values and a higher PUFA/SFA ratio, due to greater linolenic acid (C18:3) levels.     

干腌火腿皮下脂肪的特性与食用品质的关系

根据国外干腌火腿的研究结果,分析火腿皮下脂肪组织的组成特点及在加工过程中的变化,发现含有2个或3个不饱和脂肪酸的三酰基甘油酯(POO,OOL和POL),熔点较低,在常温下呈液体状态,适宜于脂肪水解酶在水-油界面的反应,优先发生水解反应,释放出棕榈酸、油酸和亚油酸。在游离脂肪酸构成中,油酸和亚油酸的比例并没有增加,亚油酸的比例却明显降低,说明不饱和脂肪酸被氧化形成了其他物质。在加工期的前6个月,脂肪水解程度最大,使低熔点的三酰基甘油酯比例降低,高熔点的三酰基甘油酯比例相应提高,降低了脂肪组织的油腻感,硬度增加,色泽变成透明的玻璃状,熟制后口感脆嫩、利口。不饱和脂肪酸的适度氧化,最终形成许多挥发性化合物,赋予脂肪组织特有的腌腊风味。     

Changes in lipid composition and fatty acid profile of Nham,a Thai fermented pork sausage,during fermentation

Changes in lipid composition and fatty acid profile of Nham during fermentation were investigated. Total lipids of Nham were in the range 2–3%. The extracted lipid of initial Nham mix consisted mainly of triglycerides (TG), accounting for more than 75% of the total lipid, followed by phospholipids (PL) and a trace amount of diglycerides (DG) and free fatty acid (FFA). During fermentation, TG, DG and PL decreased with a concomitant increase in FFA, indicating lipolysis of Nham lipids during fermentation. Changes in fatty acids of the total lipids, non-polar and polar lipid fractions were observed during fermentation. In both total and non-polar lipid fractions, the major fatty acids found in a descending order were oleic (C18:1), linoleic (C18:2) and palmitic (C16:0) acids, which together accounted for 90% of the total fatty acids. Increases in fatty acid contents in both total and non-polar lipid fractions, were observed with a corresponding decrease in the quantity of fatty acids of phospholipids. As the fermentation proceeded, peroxide value generally increased while TBARS values decreased. Overall, lipid oxidation in Nham occurred during fermentation but did not cause the objectionable odour and taste in any Nham tested.     

Influence of ewe feeding systems on fatty acid composition of suckling lambs

The main objective of this study was to evaluate the effects of ewe dietary treatments on the intramuscular fatty acid composition of suckling lambs. Twenty-four pregnant Italian Merino ewes were divided into two equal groups. One group (pasture-fed group) was allowed to graze a natural pasture and the other group (stall-fed group) was penned indoors and fed with hay and concentrate. After lambing, all ewes stayed with their respective lambs for the whole experimental period. Lambs were slaughtered at 100 days of age with an average live weight of 20kg. Fatty acid profiles of milk and lamb meat (longissimus lumborum muscle) were analysed. Intramuscular fat from pasture-fed lambs showed higher (P<0.001) proportions of polyunsaturated fatty acids. The percentage of lauric (C12:0; P<0.05), palmitic (C16.0; P<0.001) and oleic (C18.1; P<0.001) fatty acids were higher in the intramuscular fat from stall-fed lambs, whereas pasture-fed lambs showed greater proportions of linolenic (C18:3; P<0.001), eicosapentaenoic (C20:5; P<0.001) and docosapentaenoic (C22:5; P<0.05) fatty acids. Moreover, the intramuscular fat from pasture-fed lambs displayed a higher (P<0.001) PUFA/SFA ratio, and a lower (p<0.001) n-6/n-3 ratio. The conjugated linoleic acid (CLA) tended to be higher (P=0.07) in the intramuscular fat from pasture-fed lambs. This study confirmed that pasture enhanced the unsaturated fatty acid profile of intramuscular fat in lambs including n-3 fatty acids.     

Effect of an elevated monounsaturated fat diet on pork carcass and meat quality traits and tissue fatty acid composition from York-crossed barrows and gilts

Fifty-seven York-crossed barrows and gilts were fed either a grain and soy diet (CONTROL with 28% C18:1) or a similar diet enriched with oleic acid (HO with 43% C18:1, Greedy-Grass OLIVA®). There were no interactions between dietary treatment and gender and there were no differences in intramuscular and subcutaneous fatty acid composition between sexes (P > 0.05). Similar primal cut yields, composition of major primal cuts, and carcass and meat quality characteristics were found for HO and CONTROL fed pigs. Apart from a few significant but small differences for some fatty acids, intramuscular fatty acid composition was similar for both dietary treatments. Subcutaneous fat from HO fed pigs had a 6.9% increase in total monounsaturated fatty acids and a 9.3% reduction in total polyunsaturated fatty acids (P < 0.05) compared with CONTROL fed animals, without adversely affecting carcass quality and producing suitable hams for processing by the meat industry.     

Influences of anatomical location and muscle quality on porcine lipid composition

Carcasses of sixty Lacombe and Lacombe cross swine fed the same high concentrate ration were selected to equally represent three muscle quality groups (pale soft exudative (PSE), normal and dark firm dry (DFD)). These carcasses were utilised to supply back and belly fat samples for the evaluation of the influences of muscle quality and anatomical location on fatty acid composition. Back fat samples had lower percentages of palmitic (C16:0) and stearic (C18:0) acids, long (≥ C18), and short (≤ C16) chain saturated fatty acids and total saturated fatty acids and higher percentages of oleic (C18:1) and linoleic (C18:2) acids, polyunsaturated fatty acids and total unsaturated fatty acids than belly fat samples. They also had a higher unsaturated fatty acid to saturated fatty acid ratio than belly fat samples. Carcasses with DFD hams and loins had lower percentages of palmitoleic (C16:1) and linoleic (C18:2) acids and polyunsaturated fatty acids in their back fat than those with PSE hams and loins. They also had higher (P < 0·05) percentages of myristic (C14: 0) and stearic (C18:0) acids and long chain saturated fatty acids (≥ C18) and lower percentages (P < 0·05) of palmitic (C16:0) and palmitoleic (C16:1) acids in their back fat than carcasses with normal hams and loins. Moreover, they had lower (P < 0·05) percentages of palmitoleic (C16:1) and linoleic (C18:2) acids and poly-unsaturated fatty acids in their belly fat than carcasses with normal and PSE hams and loins. The fact that the lipid composition of carcasses differed significantly among muscle quality groups is of considerable importance, since it implies that factors (stress) producing differences in muscle quality may also significantly influence the fatty acid composition-and thereby the physical properties of carcass lipids.     

Changes of intramuscular phospholipids and free fatty acids during the processing of Nanjing dry-cured duck

In this study, changes of intramuscular phospholipids and free fatty acids were tracked during the processing of Nanjing dry-cured duck. Phospholipids were identified and quantified by high performance liquid chromatography combined with UV and evaporative light scattering detectors. The types and quantities of free fatty acids and fatty acids derived from phospholipids were analyzed by capillary gas chromatography. The results showed that raw duck meat had high quantities of phosphatidylethanolamine, and phosphatidylcholine (37.95% and 54.07% of total phospholipids, respectively), which contained high percentages of polysaturated fatty acids. The percentages of total phospholipids, phosphatidylethanolamine, and phosphatidylcholine decreased during processing, with a concomitant increase in quantities of free fatty acids. The lipolysis of phospholipids, especially phosphatidylethanolamine is the main contributor to the increase of free fatty acids.