Beef Dripping Research Articles

Analysis of Volatile and Flavor Compounds in Grilled Lean Beef by Stir Bar Sorptive Extraction and Thermal Desorption—Gas Chromatography Mass Spectrometry

A method of stir bar sorptive extraction (SBSE) and thermal desorption (TD) with gas chromatography–mass spectrometry (GC-MS) has been developed for qualitative and quantitative analysis of volatile and flavor compounds in grilled beef. To achieve optimum extraction and analysis performance for volatile and flavor compounds, desorption temperature and solid extraction conditions of the method were studied. Grilled beef and grilled beef dripping were analyzed by the developed method with short analysis program, and a total of 57 volatile (31 flavor) compounds, including 12 aldehydes, 13 hydrocarbons, 12 alcohols and ketones, 9 nitrogen- and sulfur-containing compounds, and 10 pyrazine compounds, were identified with little variation in triplicates. Four typical flavor compounds: hexanal, methional, 2-ethyl-pyrazine, and nonanal, were selected from main flavor group for quantitative analysis, and the method showed good linearity within the tested concentration range from 2 ng/g to 0.2 μg/g (n = 3, RSDs 0.998) and good recovery at 38∼45 % by spiked standards of 100 ng/g (n = 3, RSDs ≤ 11 %) in ground grilled beef. The limits of detection (LOD) range was 0.17–0.26 ng/g (S/N = 3, n = 3), and the limits of quantification (LOQ) range was 0.56–0.88 ng/g (S/N = 9, n = 3) for flavor analysts. The simple, fast, and solvent-less method allows us to obtain reliable qualitative and quantitative data of volatile and flavor constituents which are necessary for the beef quality evaluation.

Cardiovascular diseases and red meat

Cardiovascular diseases and red meat

Consumption of cholesterol oxides from fast foods fried in beef fat in New Zealand

AbstractLevels of cholesterol oxides were determined in samples of beef dripping used for deep frying in retail fast‐food outlets in Christchurch, New Zealand. The average levels (n = 8) of cholesterol oxides were: β‐epoxy cholesterol (15 mg/kg), α‐epoxy cholesterol, 7β‐hydroxy cholesterol, 7‐keto cholesterol (10 mg/kg each), 7α‐hydroxy cholesterol (5 mg/kg), and cholestane triol, 25‐hydroxy cholesterol (1 mg/kg each). Based on the amount of fat in a typical deep‐fried “fish and chips” meal, the amounts of individual cholesterol oxides consumed would then range from 0.05–0.7 mg. This is three to nine times less than reported in a test meal experiment with humans but could still be expected to cause detectable increases in plasma cholesterol oxide levels.

Quality and consumption of oxidized lipids from deep‐frying fats and oils in New Zealand

AbstractSamples of beef dripping and plant oil‐based deep‐frying fat were obtained from fast‐food premises in Christchurch, New Zealand, as well as samples of deep‐fried battered fish and potato chips. The fat in these samples was analyzed for level of oxidation by measuring acid value, peroxide value, polar compounds, thiobarbituric acid‐reactive substances (TBARS), and conjugated dienes. The acid and peroxide value results were contradictory when compared with limits set in the New Zealand Food Regulations 1984, but the levels of polar compounds were generally below 25%, indicating that the fats were well maintained. The TBARS and conjugated diene levels were compared with those for oxidized corn oil used in a feeding trial and indicated a similar oxidation level, although the amount of fat consumed in the feeding trial would be 30–50% higher. These results show that well‐maintained deep‐frying fat has oxidation levels sufficient to cause elevation of plasma lipid oxidation levels as observed in a human feeding trial.

TransFatty Acid Content of Selected New Zealand Foods

The fatty acid composition andtransfatty acid content of samples of New Zealand foods representing certain food groups have been determined by a combined gas chromatography/infrared spectroscopy method. The mean levels oftransfatty acids in the fat portion of these foods are (g/100 g fatty acids) margarine, 16.4; table spreads, 15.7; butter/margarine blends, 9.6; butter, 6.4; pastry, 6.2; potato chips (deep fried in beef dripping), 5.6; cakes, 5.3, crackers, 2.0; sweet biscuits, 1.9; potato crisps, 0.5. Expressed as a proportion of dry weight of food the meantransfatty acid content values are (g/100 g dry weight) margarine, 14.9; table spreads, 14.4; butter/margarine blends, 8.1; butter, 6.0; potato chips (deep fried in beef dripping), 1.6; pastry, 1.2; cakes, 0.9, crackers, 0.3; sweet biscuits, 0.2; potato crisps, 0.2. In contrast to North America, hydrogenated plant oils with high levels oftransfatty acids do not appear to be present in the New Zealand food supply.

Conversion of IQ to 7-OHIQ by gut microflora.

The rates of conversion of 2-amino-3-methyl-3H-imidazo[4,5-f]quinoline (IQ) to its reportedly mutagenic 7-keto derivative (7-OHIQ) by intestinal bacteria from humans, mice, and rats were compared. IQ was metabolized faster by cecal contents from rats or mice than by human fecal samples (113 and 87 mumol 7-OHIQ formed/hr/g cecal contents, respectively, vs. 12.3 mumol/hr/g feces). Cecal contents from germ-free rats colonized with human fecal bacteria [human flora-associated (HFA) rats] converted IQ to 7-OHIQ at rates generally lower than contents from rats colonized with their native flora. Diet had a marked effect on IQ metabolism by HFA rat cecal contents. The rate of IQ conversion to 7-OHIQ was increased in rats fed a diet high in beef dripping compared with that in rats fed a low-fat control diet. A diet high in olive oil, however, did not produce an increase in the IQ conversion rate. Addition of fiber to a purified diet increased the rate of IQ metabolism in the following order: sugar beet fiber > wheat bran > oat bran fiber > fiber-free diet. In a further study, HFA rats were fed human diets altered independently in their fat, fiber (wheat bran), and beef contents. The high-fiber diet produced the greatest increase in IQ conversion rate, followed by the high-fat diet. The diet with a high beef content and the control diet (low levels of all 3 macrocomponents) produced similarly low rates of IQ conversion. Material from incubations of IQ with HFA rat cecal contents, assumed to be 7-OHIQ on the basis of chromatographic behavior, was confirmed to be directly mutagenic, producing approximately 800 His+ revertants per microgram with S. typhimurium TA98.

Effect of chilling on the hardness of fat on sides of beef

The effect of chilling procedure on the resulting hardness (i.e. cutability) of subcutaneous adipose tissue (fat) on sides of beef has been objectively investigated using a sliding pin consistometer (SPC). Instrument readings obtained from a model system of samples of beef dripping (made with subcutaneous adipose tissue and kidney fat but without added bone trim) indicated fat hardness could be significantly ( P < 0·05) influenced by chilling procedure. However, for sides from 19 grass-fed animals which were chilled using either a ‘hot’ or ‘cold’ extreme treatment which would comply with current Australian Regulations (i.e. 20°C deep butt temperature in 20h) there was no significant difference 20 h post mortem between the hardness of the fat at a temperature of 10°C. It would appear, therefore, that the hardness of the fat on sides of chilled beef cannot be managed through manipulation of the chilling procedure in conventional processing.

The hepatic conversion of some heterocyclic amines to bacterial mutagens is modified by dietary fat and cholesterol.

Groups of Sprague-Dawley rats were fed on diets containing increasing amounts of beef dripping, but having a constant cholesterol content. One group of rats was fed on a diet containing no dripping and no added cholesterol (control). We have studied the ability of individual hepatic S9 preparations to activate the cooked food mutagens 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQX) to bacterial mutagens using Salmonella typhimurium TA98 as indicator. Hepatic preparations from animals fed on a high cholesterol, low-fat diet were less effective in activating the mutagens than preparations from rats fed on the control diet. It was also observed that the capacity of hepatic preparations to activate these mutagens increased as the amount of dripping in the diet increased. These results suggest that it is the triglyceride rather than the cholesterol content of beef dripping which promotes increased mutagen activation capacity in the liver.

Body lipids of guinea pigs exposed to different dietary fats from mid-gestation to 3 months of age. V. The fatty acid composition of brain lipids at birth.

Pregnant guinea pigs were fed on one of three diets: a commercial low-fat diet or a high-fat diet containing either maize oil or beef dripping. The young were killed at birth, the brain removed and dissected into three regions; the cerebellum, cerebrum and stem. The fatty acid composition of the major phospholipid classes, phosphatidylcholine and phosphatidylethanolamine was determined using gas chromatography. Compared with those fed the commercial or beef dripping diet the brain of the young of mothers fed maize oil during pregnancy had an increased percentage of linoleic acid and of its long-chain derivatives arachidonic acid and docosapentaenoic acid and a lower percentage of docosahexaenoic acid. These changes occurred in both lipid classes and in all regions of the brain. The results demonstrate that the fatty acid composition of the brain lipids of newborn guinea pigs can be influenced by the nature of the maternal dietary fat consumed during the last weeks of pregnancy.

Body Lipids of Guinea Pigs Exposed to Different Dietary Fats from Mid-Gestation to 3 Months of Age

Pregnant guinea pigs were fed one of three diets: a control low-fat diet, or a high-fat diet containing maize oil or beef dripping. At birth some animals were killed and the remainder reared on the same diet as their mothers till 3 months old. Body weight, weight of various adipose tissue depots, size and number of fat cells were measured. Animals fed high-fat diets were fatter than control animals. On all diets females were fatter than males. In both instances the increase in adipose tissue mass was attributable to enlargement of fat cells. The composition of dietary fat had little influence on the cellularity of adipose tissue.

Body Lipids of Guinea Pigs Exposed to Different Dietary Fats from Mid-Gestation to 3 Months of Age

Pregnant guinea pigs were fed one of three diets: a commercial low-fat diet, or a high-fat diet containing maize oil or beef dripping. The young were killed at birth and the fatty acid composition of the lipids of the liver, plasma, adipose tissue, quadriceps muscle and red cell membranes was determined. Compared with those fed the commercial diet the tissue of the young of mothers fed maize oil had an increased percentage of linoleic acid whereas in those of the young of mothers fed beef dripping, the percentage of oleic acid was significantly higher. These changes occurred both in the triglycerides and in the membrane phospholipids (with the exceptin of sphingomyelins) of all tissues examined. These results demonstrate that the fatty acid composition of the tissue lipids of the newborn guinea pig can be influenced by the fatty acid composition of the maternal diet. Changes in the fatty acid composition of membrane phospholipids can be as great as those in storage lipids. This raises the question of long-term physiological significance for the animal.

Body lipids of guinea pigs exposed to different dietary fats from mid-gestation to 3 months of age. III. The fatty acid composition of the lipids of plasma, adipose tissue, liver and muscle at 3 months of age.

Pregnant guinea pigs were fed one of three diets: a 'control' low-fat diet, or a high-fat diet containing maize oil or beef dripping. Offspring were reared on the same diet as their mothers and when they were 3 months old, fatty acid compositions of the lipids of the adipose tissue, blood plasma, liver and muscle were analysed. The proportion of linoleic acid was elevated in both the storage triglycerides and the tissue phosphoglycerides of animals fed 'maize' diet whereas in the 'beef' group the proportion of oleic acid was significantly elevated compared with controls. A substantial part of these diet-induced changes in tissue fatty acid composition had occurred by the time animal was born; only minor changes took place in the subsequent 3 months of feeding.

DIETARY FACTORS AFFECTING THE LEVEL OF PLASMA CHOLESTEROL IN HUMANS: THE ROLE OF FAT

Three dietary experiments have been performed in which 36, 37, and 49 male medical students and staff members participated as experimental subjects. In each study, everyone consumed the same homogeneous formula diet for eight days at which time they were divided into five groups. One group was maintained on the original diet for a further eight days and the others were given diets varying in respect of the level and nature of the fat moiety. Protein supplied 16.9% of total calories in all experimental rations. In the first experiment, 37 subjects ingested a diet providing 58.5% of calories as corn oil. During the initial period the average of the individual percentage decreases in plasma cholesterol was 32.0 (P = &lt; 0.01). Those continuing on corn oil displayed a further insignificant decrease. The others, receiving diets high in beef dripping, chicken fat, lard, and butter showed average individual percentage increases of 11.7 (P = &gt; 0.05), 12.7 (P = &gt; 0.05), 15.4 (P = &lt; 0.01), and 28.8 (P = &lt; 0.01), respectively. In the second experiment, 49 subjects consumed a fat-free diet for eight days. The average individual percentage decrease in plasma cholesterol was 22.2 (P = &lt; 0.01). Those continuing on the fat-free diet showed little further change. Those ingesting 20 and 60% of calories as corn oil showed further percentage decreases of 6.9 (P = &gt; 0.05) and 15.2 (P = &lt; 0.01), respectively. By contrast, those receiving diets providing 20 and 60%, of calories as butterfat showed respectively percentage increases of 6.6 (P = &gt; 0.05) and 21.7 (P = &lt; 0.01). In the third experiment, 36 subjects ingested for eight days a diet in which butterfat provided 60% of calories. The plasma cholesterol level remained essentially constant, and did not change significantly in those continuing on this diet for a further eight days. The composition of the fat moiety in the remaining groups in terms of per cent calories derived from butter-fat and corn oil respectively was: 45: 15; 30: 30; 15: 45; and 0: 60. The averages of the individual percentage decreases in plasma cholesterol values were, respectively, 3.9, 15.9, 27.1, and 32.0. Except for the lowest of these values all the changes are highly significant (P = &lt; 0.01). In addition to other conclusions that may be drawn from this work, these studies reveal that (1) there is a factor (or are factors) in certain animal fats that acts to elevate plasma cholesterol levels, and (2) there is a factor (or are factors) in corn oil that acts to depress plasma cholesterol levels.

DIETARY FACTORS AFFECTING THE LEVEL OF PLASMA CHOLESTEROL IN HUMANS: THE ROLE OF FAT

Three dietary experiments have been performed in which 36, 37, and 49 male medical students and staff members participated as experimental subjects. In each study, everyone consumed the same homogeneous formula diet for eight days at which time they were divided into five groups. One group was maintained on the original diet for a further eight days and the others were given diets varying in respect of the level and nature of the fat moiety. Protein supplied 16.9% of total calories in all experimental rations. In the first experiment, 37 subjects ingested a diet providing 58.5% of calories as corn oil. During the initial period the average of the individual percentage decreases in plasma cholesterol was 32.0 (P = &lt; 0.01). Those continuing on corn oil displayed a further insignificant decrease. The others, receiving diets high in beef dripping, chicken fat, lard, and butter showed average individual percentage increases of 11.7 (P = &gt; 0.05), 12.7 (P = &gt; 0.05), 15.4 (P = &lt; 0.01), and 28.8 (P = &lt; 0.01), respectively. In the second experiment, 49 subjects consumed a fat-free diet for eight days. The average individual percentage decrease in plasma cholesterol was 22.2 (P = &lt; 0.01). Those continuing on the fat-free diet showed little further change. Those ingesting 20 and 60% of calories as corn oil showed further percentage decreases of 6.9 (P = &gt; 0.05) and 15.2 (P = &lt; 0.01), respectively. By contrast, those receiving diets providing 20 and 60%, of calories as butterfat showed respectively percentage increases of 6.6 (P = &gt; 0.05) and 21.7 (P = &lt; 0.01). In the third experiment, 36 subjects ingested for eight days a diet in which butterfat provided 60% of calories. The plasma cholesterol level remained essentially constant, and did not change significantly in those continuing on this diet for a further eight days. The composition of the fat moiety in the remaining groups in terms of per cent calories derived from butter-fat and corn oil respectively was: 45: 15; 30: 30; 15: 45; and 0: 60. The averages of the individual percentage decreases in plasma cholesterol values were, respectively, 3.9, 15.9, 27.1, and 32.0. Except for the lowest of these values all the changes are highly significant (P = &lt; 0.01). In addition to other conclusions that may be drawn from this work, these studies reveal that (1) there is a factor (or are factors) in certain animal fats that acts to elevate plasma cholesterol levels, and (2) there is a factor (or are factors) in corn oil that acts to depress plasma cholesterol levels.