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Cholesterol is rapidly and quantitatively removed from butter fat by passage of the fat in hexane or benzene solution over a column of Celite impregnated with an aqueous solution of digitonin.
Butter was replaced by olive oil in a controlled 100 g fat diet in order to study the effect of saturated fats (SAFA) versus monounsaturated fats (MUFA) on small-bowel sterol excretion in eleven healthy ileostomates. Bile acids and neutral sterols were measured by gas-liquid chromatography. Net cholesterol excretion (excretion minus intake) was 84 +/- 25 mg/24 h (mean +/- SE) on the SAFA diet and increased to 218 +/- 32 mg/24 h on the MUFA diet (P less than 0.01). The bile acid excretion tended to be somewhat lower on the MUFA diet, but this was significant only for chenodeoxycholic acid. Net sterol excretion (the sum of excretion of net cholesterol and bile acids) was significantly lower on the SAFA diet than on the MUFA diet (443 +/- 60 and 529 +/- 58 mg/24 h, respectively). The immediately increased excretion of cholesterol from the small bowel could thus explain the serum cholesterol-lowering effect of a change from a SAFA-rich to a MUFA-rich diet, though the mechanism for this change is still unclear.
For almost 25 years, the central government laboratory of The Netherlands has administered a continuous program for the quality control of dairy products. The analytical work is conducted by private laboratories but monitored by the government laboratory. The design and results obtained by this program are illustrated by the determination of water and milk solids-not-fat contents in butter, using data collected monthly over a period of 19 years. Under this strict system of control, the within-laboratory reproducibility (i.e., over an extended period) is almost equal to the between-laboratory reproducibility. Most of this within-laboratory variation is from month to month, indicating that in this case the time variability dominates the between-laboratory variability.
A new cleanup procedure is described for chlorinated hydrocarbon residues in butterfat. The method is based on the dropwise addition of H2SO4 to a fat solution column and continuous removal of the lipids and the acid. The cleanup of 0.25-2.0 g fat requires only 10-40 ml sulfuric acid and 12-17 ml petroleum ether. There is no need for any further cleanup step, solvent evaporation, or centrifugation. The method is easy to standardize and is suitable for automation. At least 30 fat samples can be cleaned up manually by one analyst in one day. Recoveries were complete (greater than 90%) for polychlorinated biphenyl compounds and for 13 chlorinated pesticides of 16 examined. The method was tested on chlorinated hydrocarbon residues in commercial butter and the results were compared with those obtained with the acetonitrile method. The versatility and limitations of the method were investigated by varying the sulfuric acid strength, initial fat solution concentration, and column dimensions.
The effect of a fat-modified reduction diet with predominantly butter (diet T) respectively margarine (diet P) on the lipid metabolism was studied. The study was carried out on 30 subjects over two periods each lasting 21 days. An improvement of serum cholesterol and -triglycerides, LDL- and VLDL-cholesterol was found regardless of the diet. The proportion of HDL in serum cholesterol increased, the atherogenic index was improved.
This paper gives reasons for the following statements: 1. Restricted consumption of butter does not influence the physiological cholesterol levels. 2. An association between high cholesterol levels and the incidence of coronary sclerosis can not be demonstrated. 3. Hitherto all intervention trials do not show any effect. 4. No longer serum cholesterol can be considered as a factor of risk.
Ten laboratories collaboratively studied a liquid chromatographic (LC) method for the determination of propyl, octyl, and dodecyl gallate (PG, OG, and DG, respectively), 2,4,5-trihydroxybutyrophenone (THBP), tert-butylhydroquinone (TBHQ), nordihydroguaiaretic acid (NDGA), 2- and 3-tert-butyl-4-hydroxyanisole (BHA), 2,6-di-tert-butyl-4-hydroxy-methylphenol (Ionox-100), and 3,5-di-tert-butyl-4-hydroxytoluene (BHT) in butter oil. The 10 samples analyzed were spiked in matched pairs at about 100, 50, and 10 micrograms/g. In the method studied, antioxidants are extracted as in AOAC LC method 983.15, but different LC eluants are used to separate the 9 antioxidants. Results from 1 laboratory were rejected as not valid and were not included in any calculations. For the remaining 9 laboratories, the overall mean recoveries for PG, THBP, TBHQ, NDGA, BHA, OG, Ionox, BHT, an DG were 100.9, 97.8, 103.4, 95.4, 97.4, 93.6, 95.5, 79.0, and 96.2%, respectively. The overall reproducibility relative standard deviations were 8.55, 17.4, 25.6, 14.5, 6.60, 9.64, 10.8, 11.4, and 7.35%, respectively. The method was adopted first action by AOAC International as a modification of AOAC method 983.15.
A new triterpene alcohol was isolated fron shea butter and its structure was shown to be 24-methylenelanost-9(11)-en-3beta-ol. Gas chromatographic correlations between this triterpene alcohol and other related compounds are discussed.
Analytical methods currently employed for determination of acrylamide (AA) in two carbohydrate-rich food samples, crispbread and butter cookies, obtained commercially, and native and spiked bread extract samples have been evaluated in a collaborative study. The objective of the study was to obtain information about the performance of the participating laboratories when analysing samples with an AA content close to the limit of quantification ( LOQ) and at a higher AA level, and to investigate the influence of sample-preparation procedures on the results of the analysis. For this purpose an aqueous native extract of white bread crumb, a fortified extract, and AA standard solutions, the analyte content of which were not disclosed to the participants, were included in the study. A total of 62 laboratories, applying seven different measurement techniques and a broad spectrum of analyte extraction and sample-preparation procedures reported their analytical results. Because the measurement data were not normally distributed, they were evaluated by application of robust statistics. The relative performance of the laboratories was highlighted by calculation of z-scores. For the crispbread sample, especially, a large percentage of the calculated z-scores were outside the satisfactory range. From their distribution it became obvious that one of the analytical techniques might be biased, if not applied correctly. Consequently, the impact of the applied methods was examined in more detail. Information about the analytical technique, extraction solvent, quantity weighed, calibration method, clean-up, and the experience of the participating laboratories were extracted from the analytical protocols and transcribed into a data matrix which was evaluated by multifactor analysis of variance. The applied measurement technique seems to have a statistically significant influence on the analytical results.
This paper deals with the physicochemical characterization, including thermal behaviour, by differential scanning calorimetry of mango seed almond fat (MAF), alone and in mixtures with cocoa butter (CB). Results showed that mango almond seeds contain about 5.28-11.26% (dw) of fat. The refraction index is 1.466, the saponification index 189.0 and the iodine index 41.76. Fatty acids found in MAF are oleic, stearic, and palmitic acids (40.81%, 39.07% and 9.29% (w/w), respectively) as well as smaller amounts of linoleic, with arachidic, behenic, lignoceric, and linolenic acids, among others. Calorimetric analysis showed that MAF crystallizes between 14.6 and -24.27 degrees C with a DeltaHc of 56.06 J/g and melts between -17.1 and 53.8 degrees C, with fusion maxima at 18.54 degrees C and 40.0 degrees C for the alpha and beta polymorphic forms. Their fusion enthalpies are 70.12 and 115.7 J/g. The MAF solids content profile is very similar to that of CB, both in stabilized and non-stabilized samples. The mixing compatibility was analyzed using isosolids curves of mixtures of different compositions.
As part of two international collaborative studies, in which 14 laboratories applied capillary GLC to determine the triglyceride (TG) profile of cocoa butter, the performance of different sample introduction techniques, i.e. cold on-column injection (OCI), split injection and programmed-temperature vapouriser (PTV) injection, was compared. In both studies, the participants did not apply a uniform GLC procedure. Synthetic mixtures of triglycerides were chosen to permit an accurate determination of detector response factors. No statistically significant difference was found between the mean values obtained by different injection modes. The OCI, generally recommended as best practice, did not give superior results than the PTV or the split injection techniques.
Solid lipid nanoparticles (SLN) were prepared using cacao butter, as the lipid core, and curdlan, as the shell material. Tween 80 was used as a co-surfactant in order to prevent aggregation and gelling of the curdlan. Mannitol was used as a cryoprotectant in order to prevent aggregation during redispersion. No significant change in the size of the SLN was observed up to a lipid concentration of 1.0%, and the particle size ranged from 140 to 200 nm with a unimodal distribution. When an alternating pH between 7 and 11 was used to test the physical stability of an SLN solution, the change in the particle size remained within a narrow range up to a lipid concentration of 0.5%. Above 0.5%, the particles began to aggregate due to the insufficient amount of the coating material, curdlan and Tween 80. The critical aggregation concentration at pH 7.4 was found to be 6.95 x 10(-4) mg/ml. Pyrene was used as a fluorescence probe. As the temperature increased, pyrene was gradually released from the SLN. The loading efficiency was >75% when the verapamil to lipid ratios were 1:10 and 1:5 and decreased significantly as the ratio became 1:1. The release rate was significantly delayed when verapamil was loaded into the SLN.
Two series of 120 h mixed cultures of Pediococcus pentosaceus MITJ-10 and Lactobacillus acidophilus Hansen 1748 were grown in semisolid maize-based media, applying an orthogonal factorial design in order to establish the most adequate parameters to get compounds related to butter-like flavor. Conditions of maize pre-treatment established in the first series were hot lime-treatment for 20 min, grinding and sieving to 0.0165 in., partial defatting and cooking for 25 min. While the culture conditions established for the second series were the addition of yeast extract (0.2% w/w), and culture starting with 2x10(6) CFU g(-1) and a ratio of P. pentosaceus and L. acidophilus, 3:1. The fermentation profile was studied in a last culture. Lactic acid bacteria (LAB) prevailed over the native microorganisms, with a specific growth rate of 0.47 h(-1). Diacetyl production correlated (r2=0.9972) with the 12 h exponential growth phase of LAB. The concentration of diacetyl at that time was 779.56 mg kg(-1). The contents of lactic acid and volatile fatty acids were low at 12 h, 665 and 1312 mg kg(-1), respectively. During the long stationary phase, they increased up to 4800 and 1886 mg kg(-1), respectively. This procedure might be useful to prepare naturally aromatized raw materials for the food industry.
Dacryodes edulis is a multipurpose tree presently undergoing domestication in central Africa and the countries bordering the Gulf of Guinea, the fruits of which are a good source of essential fatty acids. Polyphenols were characterized in the skin zone and in the pulp of bush butter [Dacryodes edulis (G. Don) H.J. Lam] fruits at different stages of ripeness, from unripe to soft fruits. Total polyphenols, assayed according to the Folin-Ciocalteu method, accounted for 3.0-4.2 mg/g of fresh skin, corresponding to 18.6-21.6 mg/g of defatted dry skin, higher concentrations than in the pulp, with 1.1-1.4 mg/g of fresh weight, corresponding to 5.4-12.3 mg/g of defatted dry weight. Reversed-phase high-performance liquid chromatography revealed the presence of flavonols and anthocyanins. Flavonols appeared to be the main class, with quercitrin as the main individual compound, and the highest concentrations occurred in the skin zone. Hyperin, isoquercitrin, isorhamnetin rhamnoside, and isorhamnetin hexoside were also present in relatively high amounts. Petunidin, cyanidin, and peonidin hexosides were identified by mass spectrometry. In the course of ripening, the total polyphenols as well as the major flavonols increased slightly between unripe and preripe stages and then declined gradually as ripening progressed. Anthocyanin profiles also showed a substantial change during ripening, concomitant with the color change from pink to purple.
Current methods for the authentication of cocoa butter (CB) are mainly based on a knowledge of its triglyceride (TG) composition. The performances of capillary GLC and nonaqueous HPLC with an evaporative light-scattering detector (ELSD) for the quantification of TG of CB of different geographical origins were compared. Use of capillary columns coated with a polarizable stationary phase or two reversed-phase HPLC columns coupled in series efficiently separated the major TG species contained in CB. The velocity of the GLC carrier gas influenced the FID response factors of TG standard compounds, which were linearly related to the retention times of the analytes studied. Within a certain mass range the ELSD response of standard TG solutions did not deviate from unity to a greater extent, independent of the molecular structure of the TG species. The quantities of individual TG as obtained by both methods were in close agreement, and the precisions of the methods were also of comparable magnitude, so that either method can be applied to assess the purity of CB. Capillary GLC has the advantage of higher sample throughput due to a shorter run time and because the consumption of chemicals is negligible.
Cell growth, lipid accumulation and cellular lipid composition of Yarrowia lipolytica growing on mixtures of industrial fats containing stearic, oleic, linoleic and palmitic acid have been studied. During growth, the strain incorporated oleic and linoleic acids more rapidly than the saturated fatty acids. Relatively high lipid accumulation (up to 0.44 g of lipids per g of dry matter) was observed when stearic acid was included in the culture medium. In contrast, substrates rich in oleic acid did not favor cellular lipid accumulation. The accumulated lipids, mainly composed of triacylglycerols (45-55% w/w), demonstrated a different total fatty acid composition compared with that of the substrate; in all cases, the microorganism showed the unusual capacity to increase its cellular stearic acid level, even if this fatty acid was not found in high concentrations in the substrate. This permitted the synthesis of interesting lipid profiles with high percentages of stearic acid and non-negligible percentages of palmitic and oleic acid, with a composition resembling that of cocoa-butter.
The rat-liver carcinogen 4-dimethylaminoazobenzene (Butter Yellow, DAB) and 12 of its structural analogues have been evaluated in a cell transformation assay. Eight of these analogues have already been tested for carcinogenicity in rats, whilst the remaining 4 are new or hitherto untested. Benzidine and its 3,3'-disulphonic acid derivative have also been evaluated. The in vitro results agree with long-term animal data for 8 compounds but disagree in finding DAB-4'-sulphonic acid, 4-trifluoromethyl-DAB and 4-diethylaminoazo-benzene positive. Possible reasons for these divergencies are discussed. It is concluded that 9-phenylazojulolidine and N-methyl-5-phenylazoindoline have carcinogenic potential and that 3,5-dimethyl-4-aminoazobenzene and 4-aminoazobenzene-4'-sulphonic acid are likely to prove non-carcinogenic. Addition of azobenzene to the in vitro assay medium increases the transforming potency of DAB 25-fold. It is suggested that it acts as a competitive substrate for one of the enzymes that detoxify DAB, and that this effect is related to that produced by norharman. Sulphonic-acid derivatives of established carcinogens are usually inactive. The basis of this effect has been investigated, and it is suggested that it can operate by two separate mechanisms. It has been established that this assay cannot be relied upon to predict the in vivo potency of a carcinogen. Consideration has been given to possible changes which could be made to the liver activation system (the S-9 mix) currently used in in vitro carcinogenicity assays, and a diagram is presented of the metabolic conversions of a compound which might lead to mutation or tumour formation. This enables the term potential carcinogen to be accurately defined, and indicates a possible difference between absolute non-carcinogens and compounds which fail to produce cancer in vivo.
High-performance thin-layer chromatography (HPTLC) was applied to the separation and quantification of aflatoxin in 300 jars of "crunchy" peanut butter. A critical evaluation of the proposed HPTLC method has been carried out by statistical comparisons with a commercially available enzyme-linked immunosorbent assay (ELISA) kit and a high-performance liquid chromatographic (HPLC) method. The statistical tests indicated that whilst the distributions of the data sets obtained with each method were similar, the HPLC method was found to be biased. Over-all results indicated that the HPTLC method gave more consistent data, relatively lower standard deviations and lower coefficients of variation. The ELISA kit was found to be less precise than the HPTLC and HPLC methods and prone to some loss of sensitivity caused by matrix interference.