食盐腌制对秦川牛普通牛肉脂肪酸组成的影响

以秦川牛的普通牛肉为研究对象,探讨食盐腌制对牛肉脂肪酸组成的影响。采用质量浓度2、4、6、8、10、12g/100mL的食盐溶液腌制牛肉后,分别进行脂肪含量及脂肪酸的测定。结果表明：食盐腌制对普通牛肉中所检测到的16种脂肪酸组成有显著影响(P＜0.05);低质量浓度食盐腌制对脂肪含量没有显著影响(P＞0.05),对总饱和脂肪酸(SFU)和总不饱和脂肪酸(UFA)影响也都不显著(P＞0.05),但可显著降低肉豆蔻酸含量(P＜0.05),可显著增加亚油酸和二十二碳五烯酸的含量(P＜0.05);高质量浓度食盐腌制会使牛肉脂肪含量显著降低(P＜0.05),可显著增加SFU而降低UFA的含量(P＜0.05)。因此,低盐腌制对于改善秦川牛普通牛肉脂肪的营养有明显的促进作用。     

Reducing salt content of dry-cured ham: effect on lipid composition and sensory attributes

The salt content of dry-cured ham must be reduced to adapt the product to the taste of the consumer and to human health recommendations. This study dealt with the effect of lowering salt content on the lipid composition and sensory attributes of 18-month-old Corsican dry-cured hams. Six were salted according to a long time salting method and six according to a short time method (STS). The latter was lower in both total and free chlorides (4.7% v 7.3% and 1.5% v 2.0%, respectively) and in dry matter (23.8% v 25.2%). The composition of the intramuscular lipids was similar for both salting methods except that the proportion of polyunsaturated fatty acids of the phospholipids was higher in STS hams (42.3% v 34.0%). The salting method had no significant effect on the appearance of the hams (marbling, colour). However, the STS hams were less salty and their aroma notes related to fat such as rancid, fatty and buttery were more pronounced.     

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。     

Pre-cure freezing affects proteolysis in dry-cured hams

Several parameters (sodium chloride, moisture, intramuscular fat, total nitrogen, non-protein nitrogen, white precipitates, free tyrosine, L* a* b* values and acceptability) related with proteolysis during the curing were compared in dry-cured hams manufactured from refrigerated and frozen/thawed raw material. Pre-cure freezing increased the proteolysis levels significantly (p<0.05) in the zones of the ham where water losses and absorption of salt is slowest. Frozen hams present a high incidence of white precipitates, formed mainly by tyrosine crystals. The colour and acceptability scores are similar in frozen and refrigerated hams. The previous freezing and thawing process accentuates the water losses, salt absorption and proteolysis of the cured meat, although it does not significantly affect the sensory quality of the dry-cured ham.     

Hot curing Wiltshire bacon

A process combining multi-needle injection and dry salting of whole baconsides before they have been completely chilled can produce acceptable Wiltshire bacon in only 5 days from slaughter. Eating quality and storage stability of sliced and vacuum packed, hot cured bacon were similar to those of dry salted bacon made from conventionally chilled sides. The yields of hot cured and cold cured raw bacon were similar, but cooking yields of hams were over 3.0% higher with hot curing.
A continuous hot curing process from slaughter, through carcass preparation, multi-needle brine injection, dry salting to chilling could simplify Wiltshire bacon processing. The concept could be particularly useful to a processor lacking the specialized facilities for traditional immersion curing.     

Intramuscular fatty acid profile of longissimus dorsi and semitendinosus muscle from Pateri goats fed under traditional feeding system of Sindh, Pakistan

The present study was undertaken to assess the intramuscular fatty acid composition of different muscles taken from male Pateri (n=15) goats, reared on naturally grown grasses, leaves and pods of Acacia nilotica and crushed cereal, under traditional way of feeding. Goats were slaughtered with an average weight of 68±7kg and age 12±1 month. The samples were taken from longissimus dorsi region (between the 12th and 13th rib) and distal region of semitendinosus muscle. Results of total fat content and fatty acids composition does not show significant (P>0.05) variation among muscles investigated. The fatty acid composition of muscles studied were primarily composed of oleic (31.50-33.38%), followed by palmitic acid (19.84-22.05%) and stearic acid (22.25-24.91%) respectively. Muscle tissue in general contained an average 51.13% of saturated fatty acids and 48.87% of unsaturated fatty acids. The mean conjugated linoleic acid was found 0.41%, 0.43% and 0.47% in ribeye and loin portion of longissimus dorsi muscle and distal region of semitendinosus muscle, respectively.     

Separation and identification of sarcoplasmic proteins from hams from three white pig crosses containing Duroc

Denaturing polyacrylamide gel electrophoresis (SDS-PAGE) was used to separate and identify the proteins soluble in low ionic strength buffer that were extracted from Semimembranosus and Biceps femoris muscles from raw hams and after curing for 11 months. The samples analysed were taken from three white pig crosses produced by three different selective breeding enterprises: cross A (75% Duroc-25% Landrace), cross B (50% Duroc-25% Landrace-25% Large White) and cross C (75% Duroc-25% Landrace). The electrophoretic profiles for the two muscles from the raw hams were qualitatively similar, but the profiles for the muscles from the cured hams revealed changes in the electrophoretic bands in the range of 66-149 kDa. The relative concentrations of certain proteins differed in both the raw and cured hams from the three crosses. Curing resulted in the loss of electrophoretic bands, chiefly for the higher molecular weights; the appearance of new protein fragments, primarily in the range of 9-22 kDa, and quantitative variations in certain polypeptides.     

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.     

Recent advances in cured raw ham manufacture

Cured raw hams are a valuable and popular group of meat products. The consumption and international trade have increased during the last years, therefore new technologies to accelerate the production process and to increase product quality and safety are needed. In the current review, an overview of European protected cured raw hams is presented. Furthermore, traditional methods for cured raw ham production together with recent advantages in the techniques for pretreatment (trimming, blade tenderization, and freeze-thawing), curing/salting (tumbling, vacuum impregnation, pulsed pressure, ultrasound, pulsed electric fields, simultaneous thawing/salting), drying/ripening (Quick-Dry-Slice-process, oil drop application, high temperature short time process) and postprocessing (vacuum and modified atmosphere packaging, high hydrostatic pressure, high pressure carbon dioxide, high pressure carbon dioxide with ultrasound) are described. Moreover, application techniques and effects of protective cultures and starter cultures, such as molds, yeasts, coagulase-negative staphylococci and lactic acid bacteria, on cured raw ham quality and safety are reviewed.     

Lipid degradation and sensory characteristics of M. biceps femoris in dry‐cured hams from Duroc using three different processing methods

Hams from Norwegian Duroc pigs, reared and fed identically, were dry‐cured using three different processing methods: Spanish Serrano (SS), Norwegian Parma‐style (PS) and deboning before curing (ND). The fatty acid compositions of the green and dry‐cured hams were analysed in terms of their neutral lipid, phospholipid and free fatty acid contents and correlated with sensory attributes. Although the three dry‐curing processes were quite different, the hams′ lipid profiles, lipid degradation patterns and lipid‐associated sensorial characteristics differed only slightly. The phospholipids were the most extensively degraded lipid class (88, 89% and 84% degradation in PS, SS and ND hams, respectively) for all processing methods. The SS and PS hams had slightly riper sensory profiles due to their extensive conversion of fatty acids into aroma components. The free fatty acid contents of PS, SS and ND hams were 6.3, 6.2 and 7.5 times greater than those of green hams, respectively.     

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.     

Effects of dietary high-oleic acid sunflower oil, copper and vitamin E levels on the fatty acid composition and the quality of dry cured Parma ham

The effects of seven isoenergetic dietary treatments: (1) no sunflower oil, 35 mg/kg Cu, without α-tocopheryl-acetate added; (2) to (7) 6% high oleic acid sunflower oil (HOSO), 35 or 175 mg/kg Cu crossed with a 0, 100 or 200 mg/kg α-tocopherol addition, were tested on quality characteristics of dry cured Parma hams from a total 84 Large White gilts. No statistically significant effect was detected on parameters of early evaluation of seasoning loss of hams. The seasoning loss and intramuscular fat content of seasoned hams averaged 28.1 and 3.3%, respectively, with no effect of the diet composition. The CIE L*a*b* colour values taken on the surface of the lean from Parma ham were not affected by dietary oil inclusion, nor by copper levels and by α-tocopherol addition in the feed mixture, except for the 'a' value that increased in HOSO groups (P<0.01) and in groups with α-tocopherol addition (P<0.01). The TBARS values in lean were reduced by the inclusion of HOSO (P<0.05) and α-tocopherol supplementation (P<0.10). Compared to the no oil group, the Parma hams in the HOSO groups showed a higher oleic acid content in the covering fat, but not different in neutral and polar fractions from semimenbranosus muscle. The oil inclusion reduced the saturated fatty acid content in subcutaneous fat and neutral lipids fraction from muscle to 30-34% No effect of α-tocopherol and copper levels were observed on fatty acids profiles. From the subjects fed the HOSO diet softer Parma hams were produced than those fed the control diet (χ(2)<0.05), while α-tocopherol and Cu levels did not influence the sensorial evaluation of hams. The inclusion of an oleic acid rich source in heavy pig diet brought about an improved nutritional value, but also the possible need of a prolonged ageing time to achieve an ideal firmness of Parma ham. Dietary α-tocopherol supplementation improved the red colour slightly and the lipid stability in Parma ham, while the supplementation of Cu in the diet had no influence on the tested parameters.     

Composition of subcutaneous fat from dry‐cured Iberian hams as influenced by pig feeding

The triacylglycerol and free fatty acid composition and volatile profile of subcutaneous fat of three batches of dry‐cured lberian hams from pigs fed in an extensive system based on acorn and pasture (‘montanera’: MONT) or in confinement with a control diet (FEED) or a 100 mg α‐tocopheryl acetate kg^?1 enriched diet (VITE) were investigated. Triacylglycerol of subcutaneous fat of hams from pigs fed on acorn and pasture (MONT) was more unsaturated, with larger percentages of monounsaturated and polyunsaturated fatty acids, than triacylglycerol of subcutaneous fat of hams from pigs fed on concentrate feeds (FEED and VITE). However, the trend of oxidative processes was quite similar in the groups that contained antioxidants (‘montanera’ and α‐tocopherol supplementation); namely, the highest volatile contents were found in subcutaneous fat of hams from pigs fed on acorn and pasture, while α‐tocopherol supplementation gave rise to a different profile of volatile compounds in comparison with the control diet. Therefore antioxidant presence could contribute to a high intensity and quality of aroma of these hams. © 2001 Society of Chemical Industry     

Analysis of raw meat to predict proteolysis in Parma ham

Four hundred and thirty-seven pigs (223 purebred Italian Large White, 97 Italian Landrace, and 117 Duroc), were studied to examine the effect of breed on meat quality and assess the possibility of relating proteolysis of dry-cured hams to raw meat quality. The Duroc pigs had intramuscular fat contents and water holding capacities (M. Semimembranosus) significantly higher than those of the Large White and Landrace. The latter had a significantly higher pH(24h) and cathepsin B activities significantly lower than the Duroc breed. The dry-cured hams (M. Biceps femoris) from the three breeds were significantly different in proximate composition, proteolysis and weight loss at the end of ageing. Data for green hams (including salt content) were used to compute a model to fit the proteolysis of the corresponding dry-cured hams. The variables included in the model (R(2)=0.53 and P<0.01) were cathepsin B activity of raw ham, pH(24h), weight loss after the first salting step, and the salt content of the dry-cured ham. The raw hams with the highest cathepsin B activities, the lowest pH(24h), and the highest weight loss after the first salting were those in which greatest proteolysis occured.     

Pig sire type and sex effects on carcass traits,meat quality and physicochemical and sensory characteristics of Serrano dry‐cured ham

This study demonstrates that improvements in animal line selection by breeding enterprises exert a strong effect on carcass traits, meat quality and sensory characteristics of Serrano dry‐cured ham. A total of 461 pigs from the offspring of a Duroc (DU) × Landrace (LD) sow mated with two DU boars and a DU × Large White (LW) boar from three breeding enterprises were evaluated. The two DU terminal sires were significantly different (P < 0.05) in carcass conformation, backfat thickness, ham and loin yields, raw ham traits, myoglobin concentration and total pigments formed during the curing process; in addition, the two lines provided different percentages of hams (54 vs 91%) with sufficient subcutaneous fat and weight to manufacture dry‐cured Serrano hams using a slow ripening process (11 months). The DU × LW sire had the best carcass and ham traits from an economic standpoint and obtained highest scores for sensory characteristics of Serrano ham evaluated by a trained panel test; furthermore, this line provided 84% of total hams suitable for manufacturing Serrano hams by a slow process. When the sex effect was analysed, carcass and ham traits of females were more favourable, but females presented a higher incidence of pale, soft and exudative (PSE) meat and a lower percentage of hams with sufficient subcutaneous fat and weight to produce Serrano hams using a slow ripening process (61% for females and 91% for castrates). On the other hand, castrates provided Serrano hams cured by a slow procedure with better organoleptic characteristics than females. Right and left hams were similar. Copyright © 2005 Society of Chemical Industry     

Effect of dietary conjugated linoleic acid (CLA) supplementation on CLA isomers content and fatty acid composition of dry-cured Parma ham

To evaluate the effects of dietary conjugated linoleic acid (CLA) supplementation on cis-9, trans-11 and trans-10, cis-12 isomer content and on the fatty acid composition of subcutaneous adipose tissue and intramuscular lipids of biceps femoris, the lipids of 24 dry cured Parma hams, obtained from Large White pigs fed isoenergetic diets supplemented with either 0 (CON) or 0.25% (T1) CLA from 97 to 172kg live weight, were analysed by Ag(+)-HPLC and capillary GLC. The dietary treatment had no influence on lipid content of BF and subcutaneous adipose tissue but increased (P<0.01) the content of both isomers, more markedly in the latter tissue. CLA supplementation increased (P<0.01) myristic, palmitic, palmitoleic and total saturated fatty acids, and decreased oleic and eicosenoic acids in both tissues. In adipose tissue, an increase (P<0.05) in stearic acid content was observed. Supplementing the finishing diet of heavy pigs with CLA has thus shown to be an effective tool for increasing the CLA content in cured ham and, also, the saturated:unsaturated ratio of the lipids, a positive effect from a technological point of view. From a human nutritional standpoint, the changes occurring in fatty acid composition negatively affect the atherogenic and thrombogenic indexes, but probably these changes are of no particular concern, as they would only partly offset the progressive increase in the degree of unsaturation of heavy pig lipids that has occurred in recent years, as a consequence of reduced adipose depots in carcasses.     

FRESH AND PROCESSED QUALITIES OF COUNTRY-STYLE CURED HAMS FROM PUREBRED DUROC AND GENETICALLY UNDEFINED MARKET HOGS

The objective of this study was to determine country-style processing differences between hams from purebred Duroc market hogs and market hogs of unknown genetic makeup. Genetically undefined hams purchased from commercial suppliers were sampled the same day as hams from Duroc market hogs. Processing and curing followed standard commercial procedures. After curing, hams were weighed and sliced using a band saw. Slices from the approximate center of the ham were utilized to evaluate cured objective color, moisture content, pH, and salt content. There were no significant differences in cured ham yield between Duroc and genetically undefined market hogs. Intramuscular fat content was greater (P< 0.05) in hams from Duroc market hogs when compared to the hams from genetically undefined pigs. Subjective color, marbling and firmness scores were higher (P< 0.05) in hams from Duroc pigs. Objective color evaluation of cured, center-slices favored the hams from Duroc market hogs.     

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%。     

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.     

Instrumental colour of Iberian ham subcutaneous fat and lean (biceps femoris): Influence of crossbreeding and rearing system

The influence of crossbreeding (Iberian vs Iberian×Duroc 50% pigs) and rearing system (Montanera vs Pienso) on the instrumental colour of Iberian ham (subcutaneous fat and biceps femoris muscle) and the relationships to sensory appearance and chemical composition were researched by using a factorial design. In subcutaneous fat, a significant effect (p<0.05) of crossbreeding and rearing system was found: b* and chroma were larger in hams from Iberian pigs than from Iberian×Duroc (50%) pigs, and L*, a* and chroma were larger in Pienso hams than in Montanera hams. CIEL*a*b* variables of subcutaneous fat were closely related to subcutaneous fatty acid composition, the largest correlationships involving L* (L* and 18:0, 0.652, p<0.001; L* and 18:1, -0.616, p<0.001). Instrumental colour variables and sensory appearance were also correlated (L* and fat pinkness, -0.539, p<0.001). In lean (biceps femoris), instrumental colour data was not affected by crossbreeding and rearing system. CIEL*a*b* variables were not related to chemical composition (moisture, NaCl, intramuscular fat and pigment content), although they were correlated to sensory appearance (L* and marbling, 0.419, p=0.014).