Differential Thermal Isomerization: Its Role in the Analysis of Vitamin D3 in Foods

Background For nutritional purposes, the measurement of vitamin D3 (defined as the sum of vitamin D3 and previtamin D3) is required to obtain an accurate and reliable estimate of its content in foods. An often neglected aspect in the development of methods for the analysis of vitamin D3 is accounting for any potential analytical bias in the results associated with differential thermal isomerization between previtamin D and vitamin D. Conclusions For LC-UV methods using a vitamin D2 internal standard, cold saponification, or direct lipid extraction techniques should be avoided, unless chromatographic separation of vitamin D2, vitamin D3, and their previtamin forms is achieved so that UV absorbance corrections can be made. For both LC-UV and LC-MS methods using calciferol internal standards, the simplest solution to avoid analytical bias due to the presence of previtamin D is to utilize heating conditions (typically during saponification) such that previtamin D and vitamin D in the sample and the internal standard reach an equivalent equilibrium state prior to instrumental analysis. Only under such circumstances is the integration of previtamin D unnecessary to obtain accurate results for vitamin D3. Highlights A detailed discussion of the quantitation of vitamin D3 in food with concise recommendations for avoiding measurement bias as a consequence of differential thermal isomerization.

Physico-chemical, Gas Chromatography-Mass Spectrometry (GC-MS) Analysis and Cold Saponification of Wild Grapes (Lannea microcarpa Engl & K. Krause) Seed Oil

Aims: Physico-chemical, Gas Chromatography-Mass Spectrometry (GC-MS) and Cold saponification was carried out on Lannea microcarpa (Wild grape) seed oil with the aim of identifying the quality and quantity of the oil and its suitability in soap production. Study Design: Experimental and instrumental study was done to determine the physicochemical characteristics, fatty acids present in the seed oil and its suitability for soap production. Place and Duration of Study: The study was conducted at the Biochemistry Laboratory, Kebbi State University of Science and Technology, Aliero, Nigeria from May to June, 2014. Methodology: The hexane extract of the sample was obtained by complete extraction using Soxhlet extractor, physicochemical analysis was carried out. A gas chromatography coupled with mass spectroscopy detector (GC-MS) system was used for the qualitative fatty acid determination. Simple cold method saponification was used in producing the soap. Results: The powdered seed (50 g) yielded 59.21±0.01% of the oil. Results from the physicochemical analysis showed the seed oil to be dark purple in colour and partially soluble in water with the acid, iodine, saponification and peroxide values at 16± 0.01 mgKOH/g, 121.6±0.1 gI2/100 g, 231.25±0.02 mgKOH/g, 3.02±0.01 meq H2O2respectively. The relative density and refractive index of the oil are at 0.5983±0.0001 (g/cm3) and 1.43±0.01 respectively. Qualitative GC-MS revealed the following fatty acids; Decanoic acid, Palmitic acid, Stearic acid, Margaric acid, 1-octadecanoic acid, Oleic and Erucic acid. The soap produced from the seed oil has pH and Foam height, 10.18±0.01 and 105.1±0.1 (cm³) respectively. Conclusion: The present study on seeds of wild grape revealed that the oil is a viable natural product that can be utilized in thefood and cosmetic industry.

Analyzing Physicochemical Properties of Wild Grapes (Lannea Microcarpa) Seed Oil

The purpose of this study was to analyze physicochemical properties of wild grape (Lannea microcarpa) seed oil. Several characterizations were conducted, including a gas chromatography and mass spectrometry (GC-MS) and cold saponification. The analyses were also supported by measuring acid, iodine, saponification, and peroxide values. Other analyses were relative density and refractive index. Experimental results showed that the oil was dark purple with the composition of oil of 59%. The qualitative GC-MS revealed the oil contained several fatty acids, including decanoic acid, palmitic acid, stearic acid, margaric acid, 1-octadecanoic acid, oleic, and erucic acid. The soap produced from the seed oil has basic pH and relatively high foam value. When the high concentration of oil was used, the appearance of oil was very dark purple and slightly soluble in water. This is due to the fact that most of the oil compositions were non-polar structure. This result confirmed the potential use of the oil for soap and other cosmetic materials.

The Effects of Cold Saponification on the Unsaponified Fatty Acid Composition and Sensory Perception of Commercial Natural Herbal Soaps

Saponification is the process in which triglycerides are combined with a strong base to form fatty acid metal salts during the soap-making process. The distribution of unsaturated and saturated fatty acid determines the hardness, aroma, cleansing, lather, and moisturizing abilities of soaps. Plant extracts, such as rosemary, vegetable, and essential oils are frequently added to soaps to enhance quality and sensory appeal. Three natural soaps were formulated using cold saponification to produce a base or control bar (BB), hibiscus rosehip bar (H), and a forest grove bar (FG). Rosemary extract (R) or essential oil (A) blends were added as additives to each formulation prior to curing to evaluate the effects of natural plant additives on the lipid composition and sensory characteristics of these natural herbal soaps. A total of seven natural soaps, three without additives (BB, H, FG) and four with additives (BBR, HA, FGR, FGA), were manufactured and studied. The majority (86–99%) of the polyunsaturated fatty acids (5.0–7.0 µg/mg) remained unsaponified in the manufactured natural soaps regardless of feedstock used. Principal component analysis (PCA) analyses showed the unsaponifiable fatty acids were different in the hibiscus bar compared to the other bars. There was a very strong correlation between the content of unsaponified C18:3n3 and C18:1n9 in all natural soaps. These results indicate that unsaponified fatty acids are important contributors to the quality and overall sensory perception and preference of natural herbal soaps following manufacturing by cold saponification.

Review: Determination of Vitamin D in Dairy Products by High Performance Liquid Chromatography

This work reviews the methods used for the determination of vitamin D in some dairy products (milk and infant formulas) by high performance liquid chromatography (HPLC). The low vitamin D contents and the presence of interfering compounds require sample treatment and purification of the extract. The advantages and drawbacks of hot and cold saponification, direct extraction and different types of extract purification are also discussed, taking into account the lack of vitamin D stability by heating, exposure to light and oxidation. With respect to chromatographic determination, the mode (normal or reverse phase), type of column (microcolumn or conventional) and detection system (UV, electrochemical and mass spectrometry) are overviewed, considering the vitamers to be determined.

Comparison of Cholesterol Oxidation Product Preparation Methods for Subsequent Gas Chromatographic Analysis

An evaluation was made of the stability of cholesterol hydroperoxides (CHPs) under the analytical conditions and preparation methods commonly used for determination and quantification of cholesterol oxidation products (COPs). CHPs were prepared by photoxidation and separated by silica thin-layer chromatography. CHPs were individually collected by normal-phase liquid chromatography and then subjected either to reduction or to cold saponification. The corresponding hydroxyl derivatives were generated by reduction, whereas cold saponification gave rise predominantly to 7-ketocholesterol. In another test, silylated and non-silylated CHPs were separately injected into a gas chromatograph at 310°C, collected, and re-injected into a gas chromatography-mass spectrometry system. The silylated CHPs were more stable than the non-silylated ones, giving 7-ketocholesterol, 7α-and 7β-hydroxycholesterol as main degradation products. Two unknown degradation peaks were detected in both silylated and nonsilylated CHPs, having 384 as main m/z fragment. The study of their mass spectra led to the conclusion that peaks A and B correspond to 6α- and 6β-hydroxycholesterol, respectively.

Artifactual Oxidation of Cholesterol During the Analysis of Cholesterol Oxidation Products: Protective Effect of Antioxidants

To study the influence of the addition of various antioxidants and their combinations on the artifactual oxidation of cholesterol during analysis, 2 factorial experiments were performed in duplicate. In the first experiment, 2 amounts of the following antioxidants were assayed: ethylene-diaminetetraacetic acid (EDTA) disodium salt (0 and 1 mg), pyrogallol (0 and 600 μg), and butylated hydroxytoluene (BHT; 0 and 600 μg); in the second, EDTA disodium salt (0 and 1 mg), ascorbyl palmitate (0 and 600 μg), and BHT (0 and 600 μg). Under low oxidative conditions of dim light, evaporation of solvents at low temperatures, and cold saponification in darkness under nitrogen atmosphere, the addition of antioxidants showed no further protective effect. Furthermore, the presence of ascorbyl palmitate significantly increased the formation of cholesterol- 5β,6β-epoxide, and 7β-hydroxycholesterol.