Proton Nuclear Magnetic Resonance-Based Method for the Quantification of Epoxidized Methyl Oleate

Epoxidized methyl esters (EMO) with their high oxirane ring reactivity, acts as a raw material in the synthesis of various industrial chemicals including polymers, stabilizers, plasticizers, glycols, polyols, carbonyl compounds, biolubricants etc. EMO has been generally quantified by the gas chromatography (GC) and high-performance liquid chromatography (HPLC) techniques. Taking into the account of the limitations of these techniques, two qHNMR-based equations have been proposed for the quantification of EMO in the mixture of EMO and methylesters (MO). The validity of the proposed method was determined using standard mixtures of MO and EMO having different molar concentrations. The developed equations have been applied on the samples of EMO prepared from oleic acid in two-step process viz., esterification followed by epoxidation. The qHNMR-based EMO quantification showed acceptable agreement with the results obtained from HPLC analysis.     

A simple,inexpensive high resolution digital thermometer for measurement of low temperatures

A simple high resolution digital thermometer is described. The temperature measurement efficiency in the temperature range 77 to 300 K has been found to be better than ± 100 μK.     

Proteolysis of reconstituted goat whey fermented by Streptococcus thermophilus in co‐culture with commercial probiotic Lactobacillus strains

Reconstituted goat whey was fermented with the starter Streptococcus thermophilus TA‐40 in co‐culture with four probiotic adjuncts (independent treatments): Lactobacillus casei BGP93 (T1), Lactobacillus paracasei BGP1 (T2), Lb. paracasei LPC37 (T3) and Lactobacillus rhamnosus LR32 (T4). Lactobacillus populations were higher than 7 log cfu/mL after fermentation and storage. Proteolysis increased significantly (P < 0.05) during fermentation in all trials. Relative amount of low‐molecular‐weight protein fractions (<6.5 kDa) increased in goat whey trials with T1, T3 and T4 during fermentation and storage. The goat whey powder was considered a potential substrate for starter and probiotic cultures, which raised the opportunities to upgrade this by‐product into a functional food.     

New Real-Coded Genetic Algorithm Operators for Minimization of Molecular Potential Energy Function

The global minimum of the potential energy of a molecule corresponds to its most stable conformation and it dictates most of its properties. Due to the extensive search space and the massive number of local minima that propagate exponentially with molecular size, determining the global minimum of a potential energy function could prove to be significantly challenging. This study demonstrates the application of newly designed real-coded genetic algorithm (RCGA) called RX-STPM, which incorporates the use of Rayleigh crossover (RX) and scale-truncated Pareto mutator (STPM) as defined earlier for minimizing molecular potential energy functions. Computational results for problems with up to 100 degrees of freedom are compared with five other existing methods from the literature. The numerical results indicate the underlying reliability (robustness) and efficiency of the proposed approach compared to other existing algorithms with low computational costs.