Insecticidal activity of Thymus pallescens de Noë and Cymbogon citratus essential oils against Sitophilus zeamais and Tribolium castaneum.

The thrust of the study was to determine the chemical composition of the essential oils extracted from Thymus pallescens de Noé and Cymbogon citratus Stapf. as well as to evaluate their efficacy in controlling Sitophilus zeamais Motschulsky and Tribolium castaneum (Herbst) in either single or combined populations. Carvacrol (56.

Exploitation of the Genetic Variability of Diverse Metric Traits of Durum Wheat ( L. ssp. Desf.) Cultivars for Local Adaptation to Semi-Arid Regions of Algeria.

Abiotic stresses pose significant challenges to wheat farming, yet exploiting the genetic variability within germplasm collections offers an opportunity to effectively address these challenges. In this study, we investigated the genetic diversity of key agronomic traits among twenty durum wheat cultivars, with the intention to pinpoint those better suited to semi-arid conditions. Field trials were conducted at the ITGC-FDPS Institute, Setif, Algeria, during the winter season of 2021/22.

Development of a portable spectrofluorimeter for measuring the microbial spoilage of minced beef.

The evaluation of meat spoilage is based on sensory and microbiological analyses. The disadvantages of sensory analyses are its reliance on highly trained panelists, a procedure which makes it costly and unattractive for routine analyses. Moreover, the classical microbiological analyses are lengthy, costly and destructive.

Structural changes of milk components during acid-induced coagulation kinetics as studied by synchronous fluorescence and mid-infrared spectroscopy.

Dynamic oscillatory experiments and front-face synchronous fluorescence spectroscopy and mid-infrared (mid-IR) spectroscopy have been used to investigate structure evolution, at the macroscopic and molecular levels, during milk acidification kinetics. The studies were performed using skim milk, at two different temperatures (30 °C and 40 °C), to which was added glucono-δ-lactone (GDL) to generate different structural changes in casein micelles and gels. Synchronous fluorescence spectra were recorded in the 250-500 nm excitation wavelength range using an offset of 80 nm between the excitation and emission monochromators for each system during the 300 min acidification kinetics.

Optical fiber-based synchronous fluorescence spectroscopy for bacterial discrimination directly from colonies on agar plates.

The development of experimental conditions for rapid bacterial discrimination using fluorescence spectroscopy fingerprinting is presented. Colonies of Pseudomonas and related reference strains on agar plates were analyzed directly using an optic fiber coupled to a laboratory spectrofluorimeter. Spectra were collected using either classic fluorescence spectroscopy after excitation at 250 nm and 340 nm for aromatic amino acids and nucleic acids (AAA + NA) and nicotinamide adenine dinucleotide (NADH) respectively, or synchronous scanning in the excitation wavelength range 250-500 nm.

Synchronous front-face fluorescence spectroscopy coupled with parallel factors (PARAFAC) analysis to study the effects of cooking time on meat.

In this study, the potential of synchronous front-face fluorescence coupled with chemometrics has been investigated for the analysis of cooked meat. Bovine meat samples (thin slices of 5 cm diameter) taken from Longissimus dorsi muscle were cooked at 237 degrees C for 0, 1, 2, 5, 7, and 10 min under control conditions. Synchronous front-face fluorescence spectra were collected on meat samples in the excitation wavelength range of 250 to 550 nm using offsets (Delta lambda) of 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, and 160 nm between excitation and emission wavelengths.

Effects of added minerals (calcium, phosphate, and citrate) on the molecular structure of skim milk as investigated by mid-infrared and synchronous fluorescence spectroscopies coupled with chemometrics.

Minerals play an important role in the structure and stability of casein micelles: minerals and caseins in milk are in dynamic equilibrium. Front-face synchronous fluorescence and mid-infrared spectra in combination with multivariate statistical analysis have been used to investigate, at a molecular level, the effects of added minerals (calcium, phosphate, or citrate) on mineral equilibria and casein micelle structure. Synchronous fluorescence spectra were recorded in the 250-500 nm excitation wavelength range using an offset of 80 nm between the excitation and emission monochromators for skim-milk samples fortified with 0, 3, 6, and 9 mM of calcium, phosphate, or citrate at 30 degrees C and 4 degrees C.

Fluorescence spectroscopy as a promising tool for a polyphasic approach to pseudomonad taxonomy.

Fluorescence spectroscopy is an emerging tool for the analysis of biomolecules from complex matrices. We explored the potentialities of the method for the pseudomonad taxonomic purpose at the genus and species level. Emission spectra of three intrinsic fluorophores (namely, NADH, tryptophan, and the complex of aromatic amino acids and nucleic acid) were collected from whole bacterial cells.

Effects of mild heating and acidification on the molecular structure of milk components as investigated by synchronous front-face fluorescence spectroscopy coupled with parallel factor analysis.

This paper reports the potential of synchronous front-face fluorescence spectroscopy in the characterization at the molecular level of milk changes during mild heating from 4 to 50 degrees C and acidification in the pH range of 6.8 to 5.1.