Y.A. Ziprin

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.

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.

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.

Antioxidative effects of cottonseed meals as evaluated in cooked meat

Cottonseed meal samples were collected from nine cottonseed oil mills in the USA. The meal samples contained 230-1,820 ppm free gossypol and 8,300-16,480 ppm total gossypol. Finely ground meals were incorporated into ground beef with 15% fat or ground lean meats (beef semimembranosus muscle and goat lean composite), at 0-3% of the final meat mixture weight. The meat mixtures were cooked to an internal temperature of 77°C, aerobically refrigerated for 3 days, and analyzed for lipid oxidation using a distillation 2-thiobarbituric acid-reactive substances (TBARS) assay method. All the cottonseed meals were highly effective antioxidants in cooked meats, decreasing day-3 TBARS values by 77-91% with 3% addition. Estimated gossypol levels in the meat samples with 3% cottonseed meal were 7-55 ppm free gossypol (vs. the 450 ppm maximum limit set by the United States Food and Drug Administration for human food products) and 249-494 ppm total gossypol (vs. the 12,000 ppm maximum limit by the UN Food and Agriculture and World Health Organizations for food products). There was no significant correlation between the antioxidative efficacy of the meals and free or total gossypol levels.

Fatty acid profiles and lipid oxidation in beef steer muscles from different anatomical locations.

Beef muscles at four different anatomical locations (longissimus dorsi, LD; psoas major, PM; semimembranosus, SM; semitendinosus, ST) were excised 24 h post-mortem from each of 12 steer carcasses and analyzed for total lipids, fatty acid proofiles and lipid oxidation catalysts. Also, the accumulation of thiobarbituric acid (TBA)-reactive substances in ground muscles stored at 4°C was determined. Total lipids and fatty acid composition of total lipid extracts were similar among the muscles from different locations. The microsomal enzymic lipid peroxidation activity was higher for the ST than for other muscles whereas total heme pigment was lower for the ST than for others. The nonheme iron was higher for the PM and SM than for the LD and ST. The accumulation of TBA-reactive substances in stored, raw ground muscle was highest for the PM and lowest for the LD. TBA values of ground muscle samples were positively correlated with heme pigment content and microsomal enzymic lipid peroxidation activity while not correlated with nonheme iron content. It also was positively correlated with the percentage of polyunsaturated fatty acids.

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.

Carcass traits of Rambouillet and Merino × Rambouillet lambs and fatty acid profiles of muscle and subcutaneous adipose tissues as affected by new sheep production system

Rambouillet and Merino×Rambouillet lambs were assigned to production systems varying in physical environment and diet: RF (raised-floor, open-sided barn/85% oat hay-10% wheat-5% molasses), FL (feedlot/high-concentrate), and P (pasture/grazing plus supplement). Although treatment duration was varied to produce similar final weights, RF lambs were heavier than P lambs, but dressing percentages were similar. Backfat thickness was less with P and for Merino cross lambs. RF feed was higher in saturated fatty acids (SFA) percentage than FL feed and P supplement, but lower compared to pasture plants. For both breed types, muscle tissue from RF was higher in SFA and lower in polyunsaturated fatty acids (PUFA) percentage than that from FL or P. In adipose tissue, SFA and PUFA tended to be higher and monounsaturated fatty acids were lower with RF for Merino cross lambs. Nevertheless, 16:0 or 18:1 percentage differences among P, FL and RF lamb tissue samples were minor vs. large variations among their respective diets.

Effects of sheep production systems on oxidative storage stability of lean lamb patties

Rambouillet lambs were assigned to three production systems varying in physical environment and diet: RF (a new, raised-floor feeding structure, with animals fed a pelleted mixture of 85% oat hay, 7.5% barley and 7.5% molasses); FL (a feedlot, with animals fed high-concentrate rations); and P (a pasture, with animals given access to the pasture and a high-concentrate supplement). Lengths of time on feed were adjusted to produce similar final shorn weights for each system. Ground meat patties were made with knife-separable lean from hind legs and aerobically refrigerated. Fat content of patties was not significantly different between RF and FL or P, while total unsaturated fatty acid percentage was slightly lower (P<0.05) for RF treatment. Patty color (redness) was most stable for RF. Lipid oxidation in raw patties also was lower (P<0.05) for RF than FL, but oxidation in cooked patties was greater for RF.

Characteristics of pork products from swine fed a high monounsaturated fat diet: Part 3—A high-fat cured product☆

Fresh pork bellies from animals fed a control sorghum-soybean diet and a similar diet containing 12% high-oleic sunflower oil (HOSO) were cured and processed in a smokehouse to an internal temperature of 55·6°C. Cooking losses were not significantly different (p < 0·05) between bacon strips from animals on the control diet and those from animals on the HOSO diet. The ratio of monounsaturated fatty acids to saturated fatty acids for the cooked rasher from the HOSO group was 1·84 times that for the cooked rasher from the control group (2·48 versus 1·35). The cooked rasher had a slightly lower (p < 0·05) percentage of total monosaturates that uncooked bacon strips within each diet group. When considering stearic acid as a fatty acid that does not raise the plasma cholesterol level in the human, along with all unsaturated fatty acids, only 16·83% and 12·26% of total fatty acids in the cooked rasher and the drip, respectively, from the HOSO group were fatty acids (C14:0 and C16:0) which may raise the plasma cholesterol level. The residual nitrite level in the raw and cooked bacon was higher (P < 0·05) for samples from the HOSO group than for those from the control group, probably due to binding of nitrite to the double bonds in unsaturated fatty acids that were higher for samples from the HOSO group. The extent of the accumulation of thiobarbituric acid-reactive substances during frozen storage was not affected (P > 0·05) by the inclusion of 12% HOSO in the animal diet, regardless of the packaging method.