Mark Keeney

Fatty acid composition of the fat in selected food items with emphasis on trans components1

The fat in 220 samples from 35 food types has been analyzed for component fatty acids by gas liquid chromatography on a 15-m capillary column coated with SP-2340. The methodology permitted the determination of trans-octadecenoic fatty acids in the food samples. For food types in which the majority of samples containedtrans fatty acids, the range (weight percent of methyl esters) of this class of acids arranged by fat content of the food types was: high fat levels (>70% fat) — animal and dairy fats, 0.3–6.6%, stick margarines, 15.9–31.0%, tub margarines, 6.8–17.6%, and vegetable shortenings, 8.7–35.4%; moderately high fat levels (40–70% fat) —diet margarines, 11.3–13.3%; moderate fat levels (10–40% fat) — breading mixes and fried crusts, 8.1–32.7%, cakes, candies and frostings, 3.2–33.2%, cream substitutes, 0.4–11.5%, cookies, 2.5–34.2%, crackers, 1.9–29.0%, pastries and pastry crusts, 0.6–31.2%, corn and mixed grain snack chips, 0.4–30.4%; low fat levels (<10% fat) - breads and rolls, 0.2–23.6%, pretzels, 10.8–29.2%, and puddings, 28.4-35.1%. The majority of samples in the following food types did not containtrans fatty acids, except in cases where the label indicated partial hydrogenation of the oil: mayonnaises and salad dressings, salad and cooking oils and potato chips. For samples in these three food types which containedtrans fatty acids, the range was 0.2-23.2%. None of the peanut butters or pizza crusts analyzed containedtrans fatty acids.

On the probable origin of some milk fat acids in rumen microbial lipids

The quantity and character of the microbial lipid isolated from rumen digesta are interpreted as indicating that significant quantities of milk fat acids originate from rumen microbial synthesis of long chain acids from volatile fatty acids. Component fatty acid patterns are presented of rumen bacterial lipid, crude rumen protozoal lipid, blood serum lipid, and milk lipid isolated from samples taken from a lactating Holstein. Certain rumen bacterial lipid fractions are shown to be very rich sources of odd carbon acids and branched acids, and it is suggested that the major source of these acids in ruminant fats is from bacterial synthesis rather than animal synthesis.

Serum uric acid, inorganic phosphorus, and glutamic-oxalacetic transaminase and blood pressure in carbohydrate-sensitive adults consuming three different levels of sucrose.

12 men and 12 women, classified as carbohydrate-sensitive on the basis of an exaggerated insulin response to a sucrose load, consumed diets containing either 5, 18, or 33% sucrose in a crossover design. The diets simulated the average American diet and consisted of identical natural and processed foods with the exception of a patty. The patty provided the experimental levels of sucrose; the difference was made up by starch. Each level of sucrose was consumed for a 6-week period. Subject body weights were maintained. Fasting serum uric acid and inorganic phosphorus increased as the level of dietary sucrose increased. Diastolic blood pressure was significantly higher when subjects were on the 33% sucrose diet as compared to the 5 and 18% diets. Serum glutamic-oxalacetic transaminase was not affected by diet. In tolerance tests after a sucrose load (2 g/kg body weight), the uric acid response was higher after the 18 and 33% sucrose diets than after the 5% sucrose diet. Serum inorganic phosphorus, which increased significantly with each level of dietary sucrose, decreased following the sucrose load. These results indicate that carbohydrate-sensitive individuals may be affected adversely by the level of sucrose commonly found in the Westernized diet. Since elevated serum uric acid and blood pressure have been identified as risk factors in degenerative diseases, this study suggests that carbohydrate-sensitive individuals should limit their sucrose consumption.

Rapid analysis of trans fatty acids on SP-2340 glass capillary columns

Abstract The application of 15-m glass capillary columns coated with SP-2340 in the analysis of trans fatty acids is demonstrated. Although resolution of cis and trans isomers is incomplete on short columns, appropriate correction factors can be applied which permit the rapid quantitative analysis of fatty acid mixtures containing trans isomers. The conditions employed permit a fairly detailed analysis of fatty acids of tissue samples in less than 30 min and the analysis of fatty acids derived from partially hydrogenated food fats in under 15 min after purification and preparation of the methyl esters.

Compounds producing the kreis color reaction with particular reference to oxidized milk fat

SummaryEvidence is presented which suggests that epihydrin aldehyde and its derivatives are not necessarily solely responsible for the Kreis color reaction of oxidized fats. Malonic dialdehyde has been shown to give a positive reaction in the Kreis test and the resulting color demonstrated to be spectrally similar to the Kreis colors obtained with epihydrin aldehyde diethyl acetal, acrolein treated with H2O2 rancid lard, and oxidized milk fat. Characteristics of a water-soluble, low molecular weight, Kreis positive, carbonyl compound from oxidized milk fat were observed to be very similar to those reported for malonic dialdehyde, i.e., strongly acidic, enolic as indicated by the ferric chloride test, and relatively stable to heating with dilute mineral acids. These properties would not be expected of epihydrin aldehyde. Three highly sensitive colorimetric reactions, involving reactions with ferric chloride, 2-thiobarbituric acid or the Kreis reagents, might well serve as the basis for quantitative measurement of malonic dialdehyde.

The lipids of some rumen holotrich protozoa

Abstract The lipids from rumen holotrich protozoa were isolated and partially identified. The lipid consisted of 70% phospholipids and 30% non-phospholipids. The phospholipids contained phosphatidyl ethanolamine (21%), phosphatidyl ethanolamine plasmalogen (22%), phosphatidyl choline (28%), and unknown phospholipids (29%). All the phospholipid fractions contained significant amounts of branched chain and unsaturated fatty acids. Degradation of the phosphatidyl ethanolamine and phosphatidyl choline with phospholipase A revealed that the branched chain and unsaturated acids were located in the beta position. Chemical degradation of the phosphatidyl ethanolamine plasmalogen indicated that the vinyl ether linkage was in the alpha position. The non-phospholipids consisted of a mixture of waxes, hydrocarbons, aliphatic alcohols, diglycerides, monoglycerides, hydroxyacids, unesterified fatty acids and sterols. The sterols and unesterified fatty acids comprised 50% of the fraction. The low concentration of stearic acid in the unesterified fatty acids (8.3%) raises a question as to the quantitative importance of holotrich protozoa in rumen hydrogenation.

Lipids ofCrassostrea virginica. I. Preliminary investigations of aldehyde and phosphorous containing lipids in oyster tissue

Oyster tissue contained 2.4% lipid, 0.14 μmole aldehyde per milligram lipid and at least 10 μg phosphorous per milligram lipid. The neutral lipid represented 58%, the glycolipid 6%, and the polar lipid 36% of the total lipid recovered after silicic acid column chromatography. Aldehydes were found in all fractions, but the presence of plasmalogen was verified in only the neutral and polar lipid fractions. At least 68% of the plasmalogen in oyster lipid was found in the polar lipid fraction. At least 13% of the phosphorous in oyster lipids was present as phosphonolipid. The distribution of phosphate and phosphonate lipids was: diacyl phospholipid 38.1%, plasmalogen phospholipid 21.8%, sphingophosphonolipid 13.5%, glyceryl ether phospholipid 8.3%, sphingophospholipid 6.9%, plasmalogen phosphonolipid 6.4%, diacyl phosphonolipid 2.6%, and glyceryl ether phosphonolipid 2.4%. When the per cent of phosphorous as phosphonolipid within the plasmalogen and glyceryl ether classes was calculated, similar values were obtained. These results support the hypothesis that there is a product precursor relationship between these two classes of lipids.

The isolation of fatty aldehydes from rumen-microbial lipid

Abstract 1. 1. The isolation of fatty aldehydes (as 2,4-dinotrophenylhydrozones) from the bacterial fraction of rumen digesta is described. 2. 2. Mixed rumen bacteria are a rich source of aldehydrogenic lipid as indicated by an aldehyde/phosphorus ration of 0.19 in the non-dialyzable lipid, and the yielding of 2.2. g of aldehyde (calculated as pentadecanal) per 100 g of total bacterial lipid. 3. 3. The major bacterial aldehydes are palmitaldehyde and C 15 branched-chain aldehydes. 4. 4. The aldehyde pattern of rumen bacteria is strikingly similar to the aldehyde patterns in certain ruminant lipids suggesting a possible origin of some ruminant aldehydes in the bacteria.

Lactation curves and effect of pup removal on milk fat of C57BI/6J mice fed different diet fats

Groups of C57BI/6J mice, fed either acis (C-Diet) ortrans diet (T-Diet) were milked without preconditioning at 6, 8, 10 and 12 dayspostpartum. On day 10, groups of mice were also milked 4, 6 and 18 h after separation of the pups. Except for the 18-h separation, all T-Diet fed animals produced milk of lower fat content than did the C-Diet animals (P<0.001) throughout the lactation period measured. In the C-Diet mice, the 6-h separation period resulted in a decrease (P<0.03) in fat, but the diet-depressed milk fat of T-Diet animals was not decreased further until the 18-h separation period. Milk volume increased as lactation progressed and was greatly increased as a result, of preconditioning (P<-0.001), even at 4 h of separation when fat was not reduced, and was always greater for T-Diet animals. Within diet groups, fatty acid composition was similar throughout the lactation period studied and was not affected by preconditioning, except in the 18-h separation period, whende novo fatty acids were significantly reduced (P≤0.05). The data are consistent with the hypothesis that preconditioning results in lowered milk fat values and that preconditioning techniques can explain discrepancies in literature values for murine milk fat.