Fortified edible oils in Bangladesh: A study on vitamin A fortification and physicochemical properties.

Food fortification has always been an effective and proven practice for eradicating various nutrient deficiencies in Bangladesh. This study investigated different quality parameters of three types (soybean, sunflower, and palm) of extensively consumed fortified edible oils in Bangladesh. Vitamin A analysis has shown that the vitamin A fortification level of most of the oil brands (73 %) did not comply with the Bangladesh Standard and Testing Institution (BSTI) standards (1.5-3.0 mg/100 g). Vitamin A contents of soybean, sunflower, and palm oil brands ranged from 0.13 to 2.06, 0.92-1.34, and 0.99-1.31 mg/100 g, respectively. Inter-brand values of vitamin A were also significantly different (p < 0.05). The majority of the samples were found to be within the acceptable ranges of Codex and BSTI, taking into account the significant chemical quality parameters for soybean, sunflower, and palm oil, such as acid value (0.31-0.93, 0.31-0.56, 0.39-0.81 mg KOH/g), free fatty acid (0.15-0.46, 0.15-0.28, 0.2-0.41 %), saponification (188.64-196.35, 186.53-188, 197.05-199.86 mg KOH/g), and peroxide values (0.06-2.9, 0.65-1.58, 1.35-1.75 meq O2/kg) respectively. All the brands' physical quality parameters (density, specific gravity, pH, viscosity, smoke point, color, and RI) complied with Codex standards. Various physical and chemical quality parameters were analyzed for significant correlations at 0.01 and 0.05 levels of significance. Remarkably, significant correlations were found between vitamin A and peroxide value (p < 0.01), iodine value and viscosity (p < 0.01), saponification value and viscosity (p < 0.01), pH and viscosity (p < 0.01), and saponification value and pH (p < 0.05). In conclusion, although the vitamin A status of most of the fortified edible oil brands was poor, the key quality indicators (except iodine value) of most of the oils were within the Codex and BSTI standard limits and were acceptable for human consumption.

Improvement of solubility of phospholipase D from Streptomyces antibioticus in recombinant Escherichia coli and its application for the enzymatic synthesis of a non-natural plasmalogen.

Plasmalogens are a subclass of glycerophospholipids that have a vinyl-ether bond at the sn-1 position and are thought to have several physiological functions. The creation of non-natural plasmalogens with functional groups is desired for the establishment of the prevention of diseases caused by the depletion of plasmalogens. Phospholipase D (PLD) has both hydrolysis and transphosphatidylation activities. In particular, PLD from Streptomyces antibioticus has been investigated extensively due to its high transphosphatidylation activity. However, it has been difficult to stably express recombinant PLD in Escherichia coli and to express it as a soluble protein. In this study, we used the E. coli strain, SoluBL21™, and achieved stable PLD expression from the T7 promoter and increased soluble fraction in the cell. We also improved the purification method of PLD using His-tag at the C terminus. We obtained PLD with ∼730 mU mg-1 protein of specific activity, and the yield was ∼420 mU l-1 culture, corresponding to 76 mU per gram of wet cells. Finally, we synthesized a non-natural plasmalogen with 1,4-cyclohexanediol bound to the phosphate group at the sn-3 position by transphosphatidylation of the purified PLD. This method will contribute to the expansion of the chemical structure library of non-natural plasmalogens.