A supercritical fluid chromatography with electrochemical detection system was developed for the simultaneous determination of tocopherol and tocotrienol isomers. The supercritical fluid chromatography with electrochemical detection system was connected with an additional pump to create a flow path to add a supporting electrolyte solution. The supporting electrolyte solution was mixed with a mobile phase in a post-column fashion, enabling the independent control of the separation and detection. After optimization of the measurement conditions, vitamin E isomers and an internal standard substance (2,2,5,7,8-pentamethyl-6-hydroxychroman) were separated within 30 min using a mixture of supercritical carbon dioxide and methanol (99:1, v/v) as a mobile phase and a cyanopropyl column (4.6 mm inner diameter × 250 mm length, 5 μm). For the electrochemical detection, methanol containing 1.0 mol/L ammonium acetate was used as a supporting electrolyte solution, and the applied potential was set at +0.8 V. This analytical method showed good linearity (5-100 μg/mL) and repeatability (less than 2.5% relative standard deviation, n = 6) and was applicable to the determination of tocopherol and tocotrienol isomers in nutrition supplements.

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Tocotrienols as important components of vitamin E have attracted increasing attention, with recent progress made in their heterologous biosynthesis, but all as intracellular products. Aiming to further improve the tocotrienol production capacity of engineered yeast and to advance toward industrial fermentation of tocotrienols, we first optimized the synthetic pathway to enhance the tocotrienol yield and then attempted to realize their secretory production by exploring biphasic extractive fermentation conditions and screening for endogenous transporters. Finally, a Saccharomyces cerevisiae strain with tocotrienol yield of 25.57 mg/g dry cell weight was generated, and the tocotrienol titer reached 82.68 mg/L in shake-flask cultures, with 73.66% of the product secreted into the organic phase. For the first time, we have reported that the vitamin E components could be harvested as extracellular products of microbial cell factories, which could largely simplify the downstream process and could be of significance for fermentative production of these products.

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Purpose: Contact lens-based drug delivery has many advantages over eye drops including higher bioavailability and sustained release. Commercial contact lenses release drug rapidly necessitating integration of control-release mechanisms into the lenses such as incorporation of vitamin E diffusion barriers. In prior publications, vitamin E barriers are loaded by placing the lenses in vitamin E-ethanol solution, followed by the ethanol extraction. In this article, we investigate feasibility of manufacturing vitamin E barriers by soaking contact lenses in vitamin E dissolved in ethanol-water solutions to minimize swelling. Methods: Contact lenses are soaked in solutions of vitamin E dissolved in ethanol-water mixtures. The dynamics of vitamin E transport into the measured and fitted to diffusion equation to determine diffusivity and partition coefficient. Vitamin E loaded lenses are imaged and transport of hydrophilic drug timolol is measured. Results: The partition coefficient of vitamin E increases more than 5 and 10-fold when the water content in the loading solution reaches 15% and 25% (v/v), respectively. The solubility of vitamin E in the solutions decreases as water fraction increases but the increase in partition coefficient allows for loading > 20% vitamin E in the lens. The barriers manufactured by this approach are effective at sustaining release of glaucoma drug timolol. Conclusions: Vitamin E barriers can be incorporated into contact lenses by soaking in solutions of vitamin E in water and ethanol. Vitamin E barriers extended hydrophilic drug release and the reduced swelling is beneficial in minimizing the possibility of lens damage during loading of vitamin E.

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Vitamin E (VitE) production from crude palm oil (CPO) has been extensively studied and industrially conducted. VitE in CPO is in the range of 600 to 1,000 ppm, and is usually produced from one of the main by-products of edible palm oil production, namely palm fatty acid distillate (PFAD). PFAD contains 4,000 to 5,500 ppm of VitE, and is produced from deodorization process of palm oil purification. This paper presents an innovative process of VitE concentrate production from CPO. A scrubber was designed and installed between the deodorizer and conventional PFAD scrubber. The main objective of this new scrubber was a recovery of glycerides from PFAD. This new scrubber is operated at 150 to 160℃. The scrubbed oil is named as Scrubbed Palm Fatty Acid Distillate (S-PFAD). This simple and efficient modified process can retrieve glycerides as S-PFAD at 0.3% recovery and it enhances VitE concentration in S-PFAD to the range of 28,000 to 32,000 ppm, which is the highest concentration of VitE that has ever been produced in the palm oil production. Fatty acids and glycerides in S-PFAD were esterified and transesterified to methyl esters. The methyl esters were evaporated from S-PFAD, and S-PFAD residue oil contained 24.7% VitE.

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Herein, we have designed an alcohol-free and low-surfactant microemulsion to safely and effectively supply α-linolenic acid (ALA) and vitamin E (VE). Ternary phase diagrams show that the use of medium- or short-chain alcohols as the co-surfactant (CoS) was unfavorable for the formation of the ALA microemulsion due to the competitive hydrogen bonding effect and vitamin E succinate (VES) significantly increased the ALA microemulsion region by improving the hydrophilicity of the oil phase. The optimal microemulsion formulation (M_av) was 6.86% ALA, 1.14% VES, 12% surfactant and 80% water, with uniformly dispersed spherical particles with diameters of ~ 25.41 nm and viscosity of 35.17 mPa·s. The M_av was stable to high temperature, ionic strength and pH, and exhibited good physical and anti-oxidation stability. The M_av facilitated the release and hydrolysis of VES, indicating that the CoS-free microemulsion with low surfactant content is promising for the safe and effective supply of ALA and VE.

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Vitamin E is essential for human health and plays positive roles in anti-oxidation. Previously, we detected large variation in vitamin E content among 161 oil palm accessions. In this study, twenty oil palm accessions with distinct variation in vitamin E contents (171.30 to 1 258.50 ppm) were selected for genetic variation analysis and developing functional markers associated with vitamin E contents. Thirty-seven homologous genes in oil palm belonging to vitamin E biosynthesis pathway were identified via BLASTP analysis, the lengths of which ranged from 426 to 25 717 bp (average 7 089 bp). Multiplex PCR sequencing for the 37 genes found 1 703 SNPs and 85 indels among the 20 oil palm accessions, with 226 SNPs locating in the coding regions. Clustering analysis for these polymorphic loci showed that the 20 oil palm accessions could be divided into five groups. Among these groups, group I included eight oil palm accessions whose vitamin E content (mean value: 893.50 ppm) was far higher than other groups (mean value 256.29 to 532.94 ppm). Correlation analysis between the markers and vitamin E traits showed that 134 SNP and 7 indel markers were significantly (p < 0.05) related with total vitamin E content. Among these functional markers, the indel EgTMT-1-24 was highly correlated with variation in vitamin E content, especially tocotrienol content. Our study identified a number of candidate function associated markers and provided clues for further research into molecular breeding for high vitamin E content oil palm.

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We studied the diffusion properties of lipophilic vitamin E (VE) through bicontinuous microemulsions (BME) using both electrochemical and fluorescence correlation spectroscopy (FCS) measurements. We investigated the effect of different composition ratios of micro-water and micro-oil phases in BMEs (W/O_BME). When we employed the BME with a lower W/O_BME value of 40/60 (oil-rich BME) as an electrolyte solution, we obtained a larger current response from VE at a fluorinated nanocarbon film electrode. Further voltammetric studies revealed that a higher VE diffusion coefficient was observed in the oil-rich BME. The FCS results also exhibited faster diffusion through the oil-rich BME, which played a significant role in accelerating the VE diffusion probably due to the widening of the micro-oil phase pathway in the BME. Moreover, the effect of increasing the VE diffusion was pronounced at the interface between the electrode surface and the BME solution. These results indicate that controlling the conditions of the BME as the measurement electrolyte is very effective for achieving superior electrochemical measurements in a BME.

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