Rapid Determination of Cholesterol in Milk and Milk Products by Direct Saponification and Capillary Gas Chromatography
TL;DR: Overall recovery was 98.6%, and the linearity was excellent for the fortification range examined, which suggested an overall relative standard deviation value of 1.4%.
About: This article is published in Journal of Dairy Science.The article was published on 1998-11-01 and is currently open access. It has received 131 citations till now. The article focuses on the topics: Gas chromatography & Sample preparation.
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TL;DR: Improved gas-liquid and high performance liquid chromatography were used and data on the trans and cis isomers of fatty acid and of conjugated linoleic acids are given, and the analyses are described.
881 citations
Cites background from "Rapid Determination of Cholesterol ..."
...Focant et al. (1998) found in another study that a daily oral supplement of α-tocopherol in the diets of cows fed rapeseed and linseed improved the resistance of fat to oxidation....
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...36/100 g Fletouris et al. (1998)...
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TL;DR: The study shows no significant difference for butterfat interesterification in terms of enzyme behavior from normal vegetable oils and fats even though it contains short-chain fatty acids and cholesterol.
Abstract: Lipase-catalyzed interesterification of butterfat blended with rapeseed oil (70/30, w/w) was investigated both in batch and in continuous reactions. Six commercially available immobilized lipases were screened in batch experiments, and the lipases, Lipozyme TL IM and Lipozyme RM IM, were chosen for further studies in a continuous packed bed reactor. TL IM gave a fast reaction and had almost reached equilibrium with a residence time of 30 min, whereas RM IM required 60 min. The effect of reaction temperature was more pronounced for RM IM. TL IM showed little effect on the interesterification degree when the temperature was raised from 60 degrees C to 90 degrees C, whereas RM IM had a positive effect when the temperature was increased from 40 degrees C to 80 degrees C. Even though TL IM is an sn-1,3 specific lipase, small changes in the sn-2 position of the triacylglycerol could be seen. The tendency was toward a reduction of the saturated fatty acid C14:0 and C16:0 and an increase of the long-chain saturated and unsaturated fatty acids (C18:0 and C18:1), especially at longer residence times (90 min). In prolonged continuous operation the activity of TL IM was high for the first 5 days, whereafter it dramatically decreased over the next 10 days to an activity level of 40%. In general, the study shows no significant difference for butterfat interesterification in terms of enzyme behavior from normal vegetable oils and fats even though it contains short-chain fatty acids and cholesterol. However, the release of short-chain fatty acids from enzymatic reactions makes the sensory quality unacceptable for direct edible applications.
99 citations
TL;DR: In this paper, a review of the cholesterol content of processed meats and processed poultry is presented, focusing on the effects of animal species, muscle fiber type, and muscle fat content.
Abstract: Available data for cholesterol content of beef, pork, poultry, and processed meat products were reported. Although the cholesterol concentration in meat and poultry can be influenced by various factors, effects of animal species, muscle fiber type, and muscle fat content are focused on in this review. Oxidative red muscles tend to have greater total lipid and cholesterol contents, although differences in the same types of muscles or cuts have been reported. Moreover, contradictory results among various studies suggest that unless there are pronounced changes in muscle structure and composition, cholesterol content is unlikely to be affected. Second, multiple issues in cholesterol analysis, including sample preparation, detection, and quantification, were evaluated. Cholesterol content of meat and poultry has been determined mostly by colorimetry and chromatography, although the latter has become predominant because of technological advances and method performance. Direct saponification has been the preferred method for hydrolyzing samples because of cost- and time-effectiveness. The extraction solvent varies, but toluene seems to provide sufficient recovery in a single extraction, although the possible formation of an emulsion associated with using toluene requires experience in postsaponification manipulation. The most commonly used internal standard is 5α-cholestane, although its behavior is not identical to that of cholesterol. Cholesterol can be analyzed routinely by gas chromatography (GC)-flame ionization detector without derivatization; however, other methods, especially high-performance liquid chromatography (HPLC) coupled with different detectors, can also be used. For research purposes, HPLC-ultraviolet/Visible/photodiode array detector with nondestructiveness is preferred, especially when cholesterol must be separated from other coexisting compounds such as tocopherols. More advanced methods, such as GC/HPLC-isotope dilution/mass spectrometry, are primarily used for quality control purposes.
93 citations
TL;DR: The ability to assimilate cholesterol in vitro and to tolerate low pH levels, gastric juice, and bile indicate that S. Cerevisiae 832, and especially S.Y. cerevisiae KK1 and I. orientalis KK5.1 may be promising candidate strains for use as probiotics.
76 citations
TL;DR: The differences in nutritional value of milk could be perceived as a milk profile marker, helping to choose the best food for human nutrition.
Abstract: (1) Background: The variation in the concentration of different components found in milk depends on mammalian species, genetic, physiological, nutritional factors, and environmental conditions. Here, we analyse, for the first time, the content of different components (cholesterol concentration and fatty acids composition as well as the overall fat and mineral content determined using the same analytical methods) in milk of different mammal species. (2) Methods: The samples (n = 52) of human, cow, sheep, goat and mare milk were analyzed in triplicate for: cholesterol concentration, fatty acids profile and fat and mineral content (calcium, magnesium, sodium, potassium, iron, zinc). (3) Results: The highest fat content was reported in sheep milk (7.10 ± 3.21 g/dL). The highest cholesterol concentration was observed in bovine (20.58 ± 4.21 mg/dL) and sheep milk (17.07 ± 1.18 mg/dL). The saturated fatty acids were the lowest in human milk (46.60 ± 7.88% of total fatty acids). Goat milk had the highest zinc (0.69 ± 0.17 mg/dL), magnesium (17.30 ± 2.70 mg/dL) and potassium (183.60 ± 17.20 mg/dL) content. Sheep milk had the highest sodium (52.10 ± 3.20 mg/dL) and calcium (181.70 ± 17.20 mg/dL) concentration values. (4) Conclusions: The differences in nutritional value of milk could be perceived as a milk profile marker, helping to choose the best food for human nutrition.
62 citations
Cites methods from "Rapid Determination of Cholesterol ..."
...71 direct saponification [31] & enzymatic method Kamelska et al....
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References
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Book•
01 Jan 1979TL;DR: A short history of HPLC can be found in this paper, where the authors present a detailed overview of the current state of the art in HPLC and its application in the literature.
Abstract: PREFACE. GLOSSARY OF SYMBOLS AND ABBREVIATIONS. 1 INTRODUCTION. 1.1 Background Information. 1.2 A Short History of HPLC. 1.3 Some Alternatives to HPLC. 1.4 Other Sources of HPLC Information. References. 2 BASIC CONCEPTS AND THE CONTROL OF SEPARATION. 2.1 Introduction. 2.2 The Chromatographic Process. 2.3 Retention. 2.4 Peak Width and the Column Plate Number N. 2.5 Resolution and Method Development. 2.6 Sample Size Effects. 2.7 RELATED TOPICS. References. 3 EQUIPMENT. 3.1 Introduction. 3.2 Reservoirs and Solvent Filtration. 3.3 Mobile-Phase Degassing. 3.4 Tubing and Fittings. 3.5 Pumping Systems. 3.6 Autosamplers. 3.7 Column Ovens. 3.8 Data Systems. 3.9 Extra-Column Effects. 3.10 Maintenance. References. 4 DETECTION. 4.1 Introduction. 4.2 Detector Characteristics. 4.3 Introduction to Individual Detectors. 4.4 UV-Visible Detectors. 4.5 Fluorescence Detectors. 4.6 Electrochemical (Amperometric) Detectors. 4.7 Radioactivity Detectors. 4.8 Conductivity Detectors. 4.9 Chemiluminescent Nitrogen Detector. 4.10 Chiral Detectors. 4.11 Refractive Index Detectors. 4.12 Light-Scattering Detectors. 4.13 Corona-Discharge Detector (CAD). 4.14 Mass Spectral Detectors (MS). 4.15 Other Hyphenated Detectors. 4.16 Sample Derivatization and Reaction Detectors. References. 5 THE COLUMN. 5.1 Introduction. 5.2 Column Supports. 5.3 Stationary Phases. 5.4 Column Selectivity. 5.5 Column Hardware. 5.6 Column-Packing Methods. 5.7 Column Specifications. 5.8 Column Handling. References. 6 REVERSED-PHASE CHROMATOGRAPHY FOR NEUTRAL SAMPLES. 6.1 Introduction. 6.2 Retention. 6.3 Selectivity. 6.4 Method Development and Strategies for Optimizing Selectivity. 6.5 Nonaqueous Reversed-Phase Chromatography (NARP). 6.6 Special Problems. References. 7 IONIC SAMPLES: REVERSED-PHASE, ION-PAIR, AND IONEXCHANGE CHROMATOGRAPHY. 7.1 Introduction. 7.2 Acid-Base Equilibria and Reversed-Phase Retention. 7.3 Separation of Ionic Samples by Reversed-Phase Chromatography (RPC). 7.4 Ion-Pair Chromatography (IPC). 7.5 Ion-Exchange Chromatography (IEC). References. 8 NORMAL-PHASE CHROMATOGRAPHY. 8.1 Introduction. 8.2 Retention. 8.3 Selectivity. 8.4 Method-Development Summary. 8.5 Problems in the Use of NPC. 8.6 Hydrophilic Interaction Chromatography (HILIC). References. 9 GRADIENT ELUTION. 9.1 Introduction. 9.2 Experimental Conditions and Their Effects on Separation. 9.3 Method Development. 9.4 Large-Molecule Separations. 9.5 Other Separation Modes. 9.6 Problems. References. 10 COMPUTER-ASSISTED METHOD DEVELOPMENT. 10.1 Introduction. 10.2 Computer-Simulation Software. 10.3 Other Method-Development Software. 10.4 Computer Simulation and Method Development. References. 11 QUALITATIVE AND QUANTITATIVE ANALYSIS. 11.1 Introduction. 11.2 Signal Measurement. 11.3 Qualitative Analysis. 11.4 Quantitative Analysis. 11.5 Summary. References. 12 METHOD VALIDATION. 12.1 Introduction. 12.2 Terms and Definitions. 12.3 System Suitability. 12.4 Documentation. 12.5 Validation for Different Pharmaceutical-Method Types. 12.6 Bioanalytical Methods. 12.7 Analytical Method Transfer (AMT). 12.8 Method Adjustment or Method Modification. 12.9 Quality Control and Quality Assurance. 12.10 Summary. References. 13 BIOCHEMICAL AND SYNTHETIC POLYMER SEPARATIONS. 13.1 Biomacromolecules. 13.2 Molecular Structure and Conformation. 13.3 Special Considerations for Biomolecule HPLC. 13.4 Separation of Peptides and Proteins. 13.5 Separation of Nucleic Acids. 13.6 Separation of Carbohydrates. 13.7 Separation of Viruses. 13.8 Size-Exclusion Chromatography (SEC). 13.9 Large-Scale Purification of Large Biomolecules. 13.10 Synthetic Polymers. References. 14 ENANTIOMER SEPARATIONS. 14.1 Introduction. 14.2 Background and Definitions. 14.3 Indirect Method. 14.4 Direct Method. 14.5 Peak Dispersion and Tailing. 14.6 Chiral Stationary Phases and Their Characteristics. 14.7 Thermodynamic Considerations. References. 15 PREPARATIVE SEPARATIONS. 15.1 Introduction. 15.2 Equipment for Prep-LC Separation. 15.3 Isocratic Elution. 15.4 Severely Overloaded Separation. 15.5 Gradient Elution. 15.6 Production-Scale Separation. References. 16 SAMPLE PREPARATION. 16.1 Introduction. 16.2 Types of Samples. 16.3 Preliminary Processing of Solid and Semi-Solid Samples. 16.4 Sample Preparation for Liquid Samples. 16.5 Liquid-Liquid Extraction. 16.6 Solid-Phase Extraction (SPE). 16.7 Membrane Techniques in Sample Preparation. 16.8 Sample Preparation Methods for Solid Samples. 16.9 Column-Switching. 16.10 Sample Preparation for Biochromatography. 16.11 Sample Preparation for LC-MS. 16.12 Derivatization in HPLC. References. 17 TROUBLESHOOTING. Quick Fix. 17.1 Introduction. 17.2 Prevention of Problems. 17.3 Problem-Isolation Strategies. 17.4 Common Symptoms of HPLC Problems. 17.5 Troubleshooting Tables. References. APPENDIX I. PROPERTIES OF HPLC SOLVENTS. I.1 Solvent-Detector Compatibility. I.1.1 UV Detection. I.1.2 RI Detection. I.1.3 MS Detection. I.2 Solvent Polarity and Selectivity. I.3 Solvent Safety. References. APPENDIX II. PREPARING BUFFERED MOBILE PHASES. II.1 Sequence of Operations. II.2 Recipes for Some Commonly Used Buffers. Reference. Index.
2,509 citations
Book•
01 Jan 1996
TL;DR: This work focuses on the analysis of Genetically Modified Organisms in Food by DNA-Based and Protein-Based Methods, and methods of Detection of Irradiated Foodstuffs and Relative Products.
Abstract: Volume 1: Optical Properties. Sensory Evaluation Techniques. Water Activity. Determination of Moisture and Ash Contents of Foods. Amino Acids. Peptides. Proteins. Enzymes. Fatty Acids. Analysis of Neutral Lipids: Triacylglycerols. Analysis of Neutral Lipids: Unsaponifiable Matter. Phospholipids. Carbohydrates and Starch. Volume 2: Mycotoxins. Phycotoxins. Residual Antibacterials in Food. Residues of Growth Promoters. Urea Pesticides Residues in Food. Organochlorine Pesticides Residues in Food. Carbamate Pesticide Residues in Food. Organophosphate Pesticide Residues in Food. Fungicide Residues. Herbicide Residues. Packaging and Other Food Contact material Residues. Polychlorobiphenyl Residues. Dioxin and Dioxin-like PCB Residues. Volume 3: Sample Preparation. Chemometrics. Particle Size Analysis. Surface Charge Analysis. Differential Scanning Calorimetry in the Analysis of Foods. Nonenzymatic Browning. Determination of Cations and Anions by Chromatographic and Electrophoretic Techniques. Methods of Detection of Irradiated Foodstuffs and Relative Products. Analysis of Meat-Containing Food. Analysis of Meat Quality. Radionuclide Concentrations in Food. Detection and Quantification of Genetically Modified Organisms in Food by DNA-Based and Protein-Based Methods. Food Adulteration. Instruments and Techniques. Biosensors for Food Analysis. Nano-scale Analysis Systems.
342 citations
TL;DR: In this article, the authors assessed the critical factors influencing the values for cholesterol determined colorimetrically, and found that the results were similar to those obtained by a commonly used gas chromatographic procedure.
Abstract: The objective of this study was to assess the critical factors influencing the values for meat cholesterol determined colorimetrically Procedure variations tested included: no saponification of total lipid extract before color development; with 15 min saponification at 80°C, with or without antioxidant protection; and with 60 min saponification at 80°C, with or without antioxidant protection Without the saponification step, meat cholesterol values were overestimated Samples with a large percentage of unsaturated fatty acids yielded higher cholesterol values when lipid extracts were saponified without antioxidant protection than with Meat cholesterol values obtained by the procedure involving 15 min saponification with antioxidant protection were similar to those obtained by a commonly used gas chromatographic procedure
165 citations
"Rapid Determination of Cholesterol ..." refers background in this paper
...Because autoxidation of cholesterol has been implicated in some rigorous hydrolysis schemes ( 4 ), the protective effect of added antioxidants before saponification was also evaluated....
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