Use of Near-Infrared–Mid-Infrared Dual-Wavelength Spectrometry to Obtain Two-Dimensional Difference Spectra of Sesame Oil as Inactive Drug Ingredient

Abstract

The present study has investigated the transformation of sesame oil kept at low temperature during a definite period of time for refinement (called winterization) as an inactive drug ingredient by using two-dimensional difference spectra (2D-DS) analysis of spectra collected by a near-infrared (NIR) and mid-infrared (MIR) dual-wavelength spectrometer (NIR/MIR-DWS). The NIR and MIR spectra were measured nearly simultaneously from samples of sesame oil before and after winterization. The difference spectrum analysis of the obtained NIR/MIR data elucidated that, after the winterization process, the absorbances at peaks attributed to C=O, C=C, and OH groups decrease while the absorbances arising from the main chain (CH2) increase. The result indicated the removal of lignan and the fatty acids with relatively short main chains. Moreover, sesame oil unwinterized was cooled from room temperature to near 1oC and subsequently warmed to room temperature. And the cycle was repeated two times. Real-time monitoring during the cooling and warming processes were carried out using the NIR/MIR-DWS. The prediction results obtained from partial least square (PLS) calibration model for the temperature suggests that there are subtle differences in the oil composition between the first cooling process and after the warming and cooling cycle. For the more detailed analysis, two-dimensional difference spectra (2D-DS) method is proposed. The results of the analyses using 2D-DS revealed that the starting point of the transformation is around 15 oC. It can be estimated that sesame oil is mainly transformed by the first cooling down. Moreover, it was implied that the structure of methylene (CH2) was significantly related to the modifications in sesame oil with temperature change. A series of experimental results elucidated that the winterization of sesame oil removed its impurities and stabilized its conditions. These results are probably the first report on the effect of the winterization process on sesame oil.

Antibacterial Activity of a Fractionated Pistacia lentiscus Oil Against Pharyngeal and Ear Pathogens, Alone or in Combination With Antibiotics

“…Winterization is a simple and cheap way of removing a wide array of fatty substances from vegetable oils. By applying the procedures described to winterize vegetable oils (Nergiz and Celikkale, 2011;Watari et al, 2020), we obtained a product enriched in AAs that we have used here to assess its possible antimicrobial effects and to further obtain a pure mixture of AAs. We focused our tests on those streptococcal pathogens (S. pyogenes and S. pneumoniae) involved in sore throat and middle ear pathologies and on two other nonstreptococcal species often provoking pathology in the middle ear (M. catarrhalis and H. influenzae).…”

“…The LO was then filtered and stored in stainless steel containers at 20 • C until bottling. Prior to testing, the sample was centrifuged at 12,000 rpm for 15 min and the supernatant was subjected to winterization, according to an already described method (Nergiz and Celikkale, 2011), to remove fatty substances and impurities and further stabilize its condition (Watari et al, 2020).…”