Effect of new DFT methods on spectroscopy and NLO analysis of 2-Bromo-5-nitrothiozole and nitrosodimethylamine

The present study reports the effect of new DFT methods introduced in Gaussian 16 viz B2PLYP, B2PLYPD, DSDPBEP86, and MPW2LPLYP on spectroscopy and nonlinear optical (NLO) properties. The 2-Bromo-5-nitrothiozole and nitrosodimethylamine are considered for the study. In addition to new methods, old DFT, MP2, and HF methods are also considered. The spectroscopic study of geometrical parameters, vibrational, electronic absorption spectra, and HOMO-LUMO gap with their molecular orbitals have been reported. The geometrical parameters such as optimized energy, dipole moment, bond length, and angles have been reported. The diffuse and polarized basis set 6-311 +  + G(d,p) has been used for the study. The first- and second-order hyperpolarizabilities have also been reported for both molecules at all methods. This study shows that these two molecules are responsive to nonlinear optical (NLO), which reflects its enhanced applicability in the development of photonic devices. The finite field approach has been applied for calculating first (β) and second hyperpolarizabilities (ϒ) respectively. The HOMO-LUMO energy gap of nitrosodimethylamine is found to be greater than that of 2-Bromo-5-nitrothiozole. Gaussian16 program package has been used for all these calculations.

Effect of partial substitution of NaCl by KCl on physicochemical properties, biogenic amines and N-nitrosamines during ripening and storage of dry-cured bacon

Effects of three salting treatments (Formulation II: 80 % NaCl + 20 % KCl; Formulation III: 60 % NaCl + 40 % KCl and Formulation IV: 40 % NaCl + 60 % KCl) on physicochemical properties, residual nitrite, N-nitrosamines and biogenic amines were compared with those of control bacons (Formulation I: 100 % NaCl) during processing and storage. Results showed that there were no significant differences among treatments for moisture, pH, and total volatile basic nitrogen (TVBN) content in dry-cured bacons during processing. The replacement of 40 % or less NaCl by KCl had no negative effects on the sensory quality of bacons during processing. Formulation III significantly reduced putrescine, cadaverine and histamine contents and enhanced nitrite residues compared with the control. After 12-day ripening and during storage, the substitution of NaCl by 60 % KCl significantly increased the N-nitrosodimethylamine (NDMA) content than the control. Principal component analysis showed that there were positive correlations between TVBN, biogenic amines (putrescine, cadaverine, histamine and tyramine) and NDMA, and negative correlation between NDMA and nitrite. These findings suggested the partial substitution of NaCl by KCl could be utilized for producing reduced-sodium dry-cured bacons to improve safety of finished products.