Characteristics of pork products from Swine Fed a high monounsaturated fat diet: Part 1-Whole muscle products

Twelve percent of high-oleic sunflower oil (HOSO) was incorporated into a swine diet to replace substantial amounts of saturated fatty acids (S) in pork by monounsaturated fatty acids (M). Pork loin chops (longissimus dorsi), cooked to 74°C, and eye of round roasts (semitendinosus), cooked to 77°C, from animals on the HOSO diet were 49% and 66%, respectively, higher in the M/S ratio as compared to their counterparts from animals on the control diet. Cooking had little effect on relative differences in the M/S ratio between HOSO and control samples. Cooking loss and sensory properties were not adversely affected by the changes in fatty acid composition. However, cooked chops and roasts from the HOSO group had lower thiobarbituric acid values during storage at 4°C.     

Microbiological characteristics of pork chops and ground pork from swine fed a high monosaturated fat diet

Twelve percent high-oleic acid sunflower oil (HOSO) was included in a swine diet to increase the ratio of monounsaturated fatty acids to saturated fatty acids in pork chops and ground pork patties. Aerobic plate counts (APCs) of pork chops prepared from animals on control and HOSO diets did not differ (P >0·05) and no specific pattern of differences in the microflora of pork chops or ground pork patties could be attributed to diet. However, after 4 days of refrigerated storage, APCs of ground pork patties from animals fed the HOSO diet were lower (P<0·05) than those of comparable patties prepared from animals fed the control diet.     

Characteristics of pork products from swine fed a high monounsaturated fat diet: Part 2-Uncured processed products

The effects of incorporation of 12% high-oleic sunflower (HOSO; >85% in oleic acid) into a swine diet on properties of uncured, processed pork products were determined. Restructured pork chops (with an initial total-fat level of <5%) and ground pork patties (with targeted initial total-fat levels of 15% and 30%) processed from animals fed the HOSO diet, when compared to the corresponding products from animals fed the control diet without HOSO, were 28% and 38%, respectively, lower (0·72 and 0·62 fold, respectively) in the proportion of total saturated fatty acids; 25% higher (1·25 fold) in the proportion of total monounsaturated fatty acids for both products; and 73% and 105%, respectively, higher in the ratio of monounsaturated to saturated fatty acids (M/S). The M/S ratio differences were not significantly changed by cooking. Cooking loss for either restructured chops or ground pork patties was similar between the product from animals on the control diet and that from animals on the HOSO diet. When restructured chops were evaluated for sensory properties, HOSO and control samples were similar in all sensory attributes evaluated for broiled chops while HOSO samples were juicier for precooked-reheated chops. Thiobarbituric acid (TBA) values were not significantly different between HOSO and control samples for stored, restructured chops; for pork patties, differences between the diet treatment groups were dependent on whether patties were stored raw or cooked.     

Effect of dietary high-oleic sunflower oil on pork carcass traits and fatty acid profiles of raw tissues

Ten gilts were randomly assigned to either a control sorghum-soybean diet or a similar diet containing 12% high-oleic sunflower oil (HOSO). No significant differences between the two groups were found in feedlot performance, carcass muscling and marbling score, but animals fed the HOSO diet had softer carcass fat and oilier carcasses than those fed the control diet. The ratio of monounsaturated fatty acids to saturated fatty acids (M/S) for subcutaneous fat increased from 1·58 in the control group to 3·76 in the HOSO group (138% increase); the M/S ratio for muscles (longissimus dorsi, semimembranosus and semitendinosus) increased from 0·96–1·19 to 1·84–1·88 (73% increase on an average). The percentage of polyunsaturated fatty acids in both adipose or muscle tissue was generally similar between the two diet treatments.     

Fatty acid profiles of the total lipids and lipid oxidation in pork muscles as affected by canola oil in the animal diet and muscle location

Twelve pigs at about 35 days of age were fed a control diet or test diets containing either 10% or 20% canola oil (CO) for 100 days. Four different muscles were excised from each carcass at 24 h post-mortem for analyses. Inclusion of 10% and 20% CO in the animal diet increased (P < 0·05) the relative amount (weight per cent) of unsaturated fatty acids in the total lipids (lipids extracted by 2:1 chloroform-methanol) by 6·7 and 15·8 percentage points, respectively, from 57·8% for the control and also increased (P < 0·05) that of polyunsaturated fatty acids by 5·5 and 9·7 percentage points, respectively, from 19·4% for the control. The 20% CO treatment increased (P < 0·05) the relative amount of monounsaturated fatty acids (primarily C18:1) by 6·1 percentage points from 38·4% for the control, while the 10% CO treatment had no significant effect. The 10% or 20% CO treatment had no significant effect on microsomal enzymic lipid peroxidation activity, heme pigment content, nonheme iron content and total lipid concentration. Overall lipid oxidation in ground muscle samples stored at 4°C tended to be higher for the 10% and 20% CO treatment groups than for the control. The tendency of increased lipid oxidation by the CO treatments apparently resulted from the increased percentages of polyunsaturated fatty acids, rather than from changes in catalytic constituents.     

Functional Characteristics, Fatty Acid Composition, and Palatability of Bacon from Pigs Fed Canola

Thirty-six pigs were fed diets containing 20% intact canola (IC), 20% ground canola (GC) or 0% canola (C). Processing yields and proximate composition of bacon were not affected by diet. Bacon from pigs fed GC had less saturated fatty acids and more monounsaturated fatty acids than bacon from pigs fed the IC or C diets. Bacon from pigs fed the C diet had less polyunsaturated fatty acids than bacon from pigs fed the IC or GC diets. Palatability of bacon from C, IC or GC treatments after 0 or 4 weeks storage was not different. After 8 weeks of storage, panelists tended to prefer control bacon over bacon from pigs fed the GC diet. Bacon from pigs fed the GC diet had higher 2-thiobarbituric acid values than bacon from pigs fed the IC or C diets.     

Effect of dietary vitamin e on the oxidative stability of raw and cooked rabbit meat

The effect of dietary α-tocopheryl acetate supplementation (200mg/kg diet) on plasma and muscle levels of α-tocopherol and the oxidative stability of raw and cooked rabbit meat was determined. Two groups of 20 male hybrid rabbits were fed the experimental diets from 35 to 80 days of age. Feed intake, live weight, feed efficiency and qualitative traits of the carcass and meat were recorded. The α-tocopherol levels in plasma and muscle were significantly higher (p≤0·01) in the supplemented group, which also showed an increase in oxidative stability in both raw and cooked meat. The higher α-tocopherol level improved the physical traits of the meat, significantly reducing shear value and increasing water-holding capacity; n-3 fatty acids in raw and cooked meat increased (p≤0·05) and the thrombogenic index decreased (p≤0·05). Dietary vitamin E did not influence weight gain, feed intake and dressing yield.     

Effect of Dietary Supplementation with α-Tocopheryl Acetate on the Stability of Reformed and Restructured Low Nitrite Cured Turkey Products

The objective of this study was to investigate the effects of sodium (Na) nitrite reduction on the oxidative and colour stability of reformed and restructured cured cooked turkey products manufactured from meat containing high and low levels of dietary α-tocopheryl acetate. Turkeys were randomly assigned to either a control group, fed a basal α-tocopheryl acetate diet (20mg/kg feed), or a treatment group fed a supplemented α-tocopheryl acetate diet (600mg/kg feed). Diets were fed ad libitum from day 1 until slaughter on day 147. Breast meat from control and treatment groups was used to manufacture cured reformed cooked turkey ham and cured restructured cooked turkey patties. Residual levels of 60 and 120mg Na nitrite/kg of meat were used. Turkey products were packaged in either overwrap or vacuum packaging and stored under refrigerated (4°C) illuminated display for 10 days. Results showed that dietary supplementation with α-tocopheryl significantly (p<0·05) improved the oxidative and colour stability of all low nitrite products produced when compared to non-supplemented controls.     

Physical and sensory attributes of hot-processed and conventionally chilled hams and bellies from electrically stimulated and non-stimulated pork carcasses

Forty-eight fresh hams and bellies were obtained from 24 market weight hogs (x = 94·5 kg) of which twelve were electrically stimulated (ES) by pulsing current immediately after exsanguination. The left side of each non-stimulated (NS) carcas was fabricated after conditioning for 3h post mortem at 17°C (NS hot-processed). The left sides of ES carcasses were fabricated 1 h pm. The right sides were fabricated following a 24 h cooler chill at 2°C (conventionally chilled: CP). Hams from ESCP carcasses had higher (P < 0·05) smokehouse yields than hams from NS carcasses. Hams that were hot-processed had higher smokehouse yields than the NSCP hams. Time of fabrication (1, 3 or 24h post mortem) did not affect smokehouse yields. Conventionally chilled bellies obtained from ES carcasses showed higher (P < 0·05) residual nitrite levels than those front electrically stimulated hot-processed (ESHP) carcasses. No differences were found for residual nitrite levels in the non-electrically stimulated sides. Panelists were unable to detect any sensory differences from the bacon strips. Sensory scores of ham slices were more juicy for non-stimulated hot-processed carcasses (NSHP) than those from ESHP carcasses. Panelists found the ham slices from NSCP carcasses to be more tender (P < 0·05) than those from electrically stimulated cold-processed (ESCP) carcasses. Results from this study clearly indicated that hot-processing of pork can provide hams and bellies that are acceptable for the production of cured hams and bacon of comparable quality and yield to those currently being produced under conventional processing methods.     

Sugar-beet pulp as an alternative ingredient of barley in rabbit diets and its effect on rabbit meat

The effects of rabbit diets with four different levels of barley and sugar-beet pulp on the dressing percentage, chemical and fatty acid composition of meat from rabbits slaughtered at a liveweight of 2000 and 2500 g have been studied. Results revealed detectable (P < 0·05) effects of the total substitution of barley by sugar-beet pulp for carcass weight, dressing percentage and dry matter from animals slaughtered at a liveweight of 2000 g. No significant differences (P > 0·05) among batches were observed when slaughter weight was 2500 g. No influence of the diet on the total lipid fatty acids was found. In general, similar results were found when rabbit diets were formulated with 50% barley and 0% sugar-beet pulp, 30% barley and 0% sugar-beet pulp or 15% barley and 15% sugar-beet pulp.     

Volatile components of cured and uncured pork: The role of nitrite and the formation of nitrogen compounds

A slice-curing method was used to prepare bacon and nitrite-free salt pork. Headspace volatiles from the cooked products, and from cooked untreated pork, were entrained on Tenax GC and analysed by combined gas chromatography-mass spectrometry. Aliphatic alcohols and aldehydes dominated the volatiles of all samples; small amounts of ketones, alkybenzenes, pyrazines, pyridines, thiazoles and furans were also present. Untreated pork and salt pork contained essentially the same volatiles, while the bacon showed a number of qualitative differences: several unsaturated and aromatic aldehydes were only present in nitrite free samples and benzonitrile, phenylacetonitrile and four alkyl nitrates were found only in bacon volatiles. The possible origins of these nitrogen-compounds from the reaction of nitrite with flavour precursors are discussed.     

FATTY ACID COMPOSITION OF LIPIDS FROM BROILERS FED SATURATED AND UNSATURATED FATS

SUMMARY— The effect of feeding saturated fat (tallow) and unsaturated fat (safflower oil) to broilers on the change in fatty acid composition of lipids deposited in broiler tissues at 4, 6, 8, and 10 wk of age was determined. Fatty acids from raw and cooked skin, excluding that on the neck and third wing joint, breast meat, thigh meat, and abdominal fat were identified by using gas liquid chromatography. Fatty acids from water in which carcasses were cooked were also identified. The degree of unsaturation of fatty acids in these tissues wars influenced by the degree of unsaturated fatty acids in the diet and tended to assume the fatty acid composition of the diet. In some cases, however, the higher levels of certain fatty acids in depot fat was not present in broilers fed the higher levels in the diet. Fatty acids in the larger amounts in all broiler tissues were palmitic, stearic, ofeic, and linoleic but varied in amount among the different age broilers fed the same ration as well as different rations. In most cases there tended to be an inverse relationship between oleic and linoleic acids in the tissues. Lipids from cooked tissues contained a larger amount of 18-carbon unsaturated fatty acids than the other fatty acids combined. Fatty acids collected from cooking water were similar to those in cooked tissues. The presence of 13- and 25-carbon chain fatty acids noted in tissues of 4 wk-old broilers suggests a difference in the metabolism of fat in different age birds. Futher research is needed to substantiate this finding.     

Effect of diet on animal performance, lipid composition of subcutaneous adipose and liver tissue of beef cattle

Two trials were carried out with Brahman beef cattle to study animal performance and carcass characteristics as well as fatty acid composition of subcutaneous adipose and hepatic tissue, as influence by length of grain feeding period or a pasturing regimen. In trial 1, steers were allotted to three feedlot finishing periods (76, 104 and 146 days) after being backgrounded on pasture. Steers fed 76 days had greater average daily gains (P < 0·05) than steers fed 146 and 104 days, respectively. Carcasses of steers slaughtered after 146 days on feed had higher (P < 0·05) marbling scores, quality grades, fat over ribeye, quality yield and per cent kidney, pelvic and heart (KPH) fat than steers fed for 104 and 76 days. The proprortions of certain fatty acid of subcutaneous fat and liver tissue were influenced by the length of grain feeding. There was a marked increased in the proportion of oleic acid in both tissues as the steers remained longer in the feedlot and a higher percentage of total saturated fatty acids at 76 days than at the other two times. Quantitative separation of hepatic lipid classes by the Iatroscan revealed that phosphatidylcholine and phosphatidylethanolamine were the main components of the phospholipids. Presents as minor components were cardiolipin and sphingomyelin. No differences (P > 0.·05) in these individual subclasses of liver lipids or in triglycerides were observed between the feedlot groups. Liver polyunsaturated fatty acids (PUFA) were higher (P < 0·001) at 104 than 76 days. In trial 2, steers fed a concentrate diet gained faster (P < 0·05) than the pasture group after 138 days. Marbling scores, yield grade, quality grade, fat over ribeye and per cent KPH were higher (P < 0·01) for the concentrate group while fat color scores were higher (P < 0·01) for the pasture group. Liver fatty acid analysis of summed ω6 PUFAs of triglyceride, phosphatidylcholine, phosphatidylethanolamine were higher for the feedlot than the pasture group. Linoleic acid was higher (P < 0·05) in the TG and PC liver subclass of the feedlot animals while higher (P < 0·05) linolenic acid occurred in the pasture group.     

N-Nitrosamine Ingestion from Consumer-Cooked Bacon

Thirty-nine fried bacon samples and corresponding fried-out fats were collected from randomly selected consumers' homes. Bacons were purchased and cooked in the course of preparing meals containing bacon. The average volatile N-nitrosamine content μg/kg) of the rasher and fried-out fat, respectively, were: N-nitrosodimethylamine, 4.0 and 5.3; N-nitrosopiperidine, 0.7 and 1.5; N-nitrosopyrrolidine, 17 and 32; N-nitrosothiazolidine, 8.9 and 3.4. The average daily ingestion of N-nitrosopyrrolidine from bacon for our survey respondents was estimated to be 76 ng/person/day. A majority of respondents indicated that they used the fried-out fat as a cooking oil.     

Effect of Belly Handling (Chilled, Frozen, Prerigor) and Smoking Delay on Regular and Sorbate-Cured Bacon

Bellies from three handling methods; fresh, frozen, or prerigor were cured with either 40 ppm sodium nitrite/0.26% potassium sorbate or 120 ppm sodium nitrite. After pumping, one group of bellies was processed (cooked and smoked) immediately, and the remaining group was held 72 hr before processing. Residual nitrite was significnatly higher in regular cure bacon and in bellies processed immediately. By 28 days after packaging, little difference was seen in residual nitrite as a result of any treatment. Regular bacon and immediate processing resulted in greater nitrosopigment conversion. Prerigor bacon had greater pigment conversion and greater residual NaCl concentrations while fresh and frozen bellies were similar. Nitrosamine levels were not influenced by belly handling variables.     

Effects of goat milk or milk replacer diet on meat quality and fat composition of suckling goat kids

The effects of a diet with goat milk "GM" or milk replacer "MR" on the meat quality and fat composition of suckling Murciano-Granadina kids were studied. MR consisted of powdered skimmed milk, coconut oil and fat, and cereal products and by-products. Raw meat quality (moisture, protein, lipids, ash, collagen, cholesterol, haem pigments, CIELab colour, pH and water retention capacity), fatty acid "FA" composition and eating quality of cooked meat (odour, flavour and texture) were determined. Diet had only a slight effect on raw meat quality but had a pronounced effect on fatty acid composition and eating quality of cooked meat. MR diet increased the water/protein proportion in the muscle. The saturated/unsaturated FA ratio in GM and MR fat was 0.94 and 2.27, respectively. The major FA in GM and MR fat were C16:0 and C18:1, respectively. Short-chain C4-C12 hardly accumulated in the adipose tissue of suckling kid, increasing the relative percentages of C14-C20. This effect was more pronounced in MR fat, due to the fact that MR contained more short-chain fatty acids than GM. MR diet gave cooked meat a more intense characteristic goat meat odour and flavour, more tenderness and more juiciness than the natural suckling diet. This fact could be related to differences in meat and fat composition.     

Dietary unsaturated fatty acids increase plasma glucagon-like peptide-1 and cholecystokinin and may decrease premeal ghrelin in lactating dairy cows

Previous reports have indicated that dietary unsaturated fat can decrease energy intake of lactating dairy cattle. However, the mechanism for this response is unclear. To evaluate the potential role of gut peptides, periprandial concentrations of cholecystokinin (CCK), glucagon-like peptide 1 (GLP-1), and ghrelin were measured. From a replicated 4 × 4 Latin square experiment, 4 cows from a single square were selected for analysis of responses to 3 treatments: a control diet (5.5% total fatty acids, 65% unsaturated), a diet with added saturated fat (SAT, 8.3% fatty acids, 47% unsaturated), and a diet with added unsaturated fat (UNS, 7.8% fatty acids, 63% unsaturated). The SAT treatment increased duodenal flow of saturated fatty acids compared with UNS and control and, despite the fact that ruminal biohydrogenation altered fatty acid profiles of digesta, UNS increased duodenal flow of unsaturated fatty acids compared with SAT and control. Blood samples were collected at 8-min intervals through the first 2 meals of the day and analyzed by commercial radioimmunoassays. The UNS treatment increased plasma CCK concentration relative to SAT and control, and increased plasma GLP-1 concentration compared with control. Furthermore, fat treatments tended to suppress the prandial ghrelin surge that was evident for control. Suppression of feed intake by unsaturated fats is likely mediated in part by increased secretion of CCK and GLP-1, and dietary fat may also inhibit ghrelin release before conditioned meals.     

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.     

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.     

Sensory, Physical, and Cooking Characteristics of Bacon Processed with Varying Levels of Sodium Nitrite and Potassium Sorbate

Sensory, physical, and cooking properties were evaluated on bacon processed under commercial operations in four separate plants. Three formulations with various levels of sodium nitrite and potassium sorbate were used: (1) 0 ppm sodium nitrite, (2) 40 ppm sodium nitrite 2600 ppm potassium sorbate, and (3) 120 ppm sodium nitrite. Sliced bacon was evaluated after 10, 30, 50, and 70 days of storage. “Chemical”-like flavors, prickly mouth sensations, and “sweet aromatic” aromas were found in bacon processed with 40 ppm sodium nitrite and 2600 ppm potassium sorbate. “Microbial” flavors were found in 0 ppm sodium nitrite bacon after 50 and 70 days of storage. Bacon stored for 30 days had less cooking loss and sensory panel scores indicative of more mouth coating with fat than did bacon stored for 10 days. The degree of leanness in bacon strips had more of an influence on textural, physical, and cooking characteristics than did sodium nitrite and potassium sorbate levels.