Rapid and non-destructive analysis of apricot fruit quality using FT-near-infrared spectroscopy

A non-destructive optical method based on near-infrared spectroscopy has been used for the evaluation of apricot fruit quality. Diffuse reflectance measurements (800–2500 nm), physical, physiological and biochemical measurements were performed individually on 877 apricot fruits from eight contrasted cultivars harvested at different ripening stages. Relationships between spectral wavelengths and quality attributes were evaluated by application of chemometric techniques based on partial least squares (PLS) on fruit set divided randomly into two groups: 598 fruits for calibration and 279 for validation. Good prediction performance was obtained for soluble solids and titratable acidity with correlation coefficients of 0.92 and 0.89 respectively and root mean square errors of prediction of 0.98% Brix and 3.62 meq 100 g⁻¹ FW respectively. For the other quality traits such as firmness, ethylene, individual sugars and organic acids, the prediction models were not satisfactorily accurate due to the high error of calibration and prediction.     

Over-production of 5-enolpyruvylshikimate-3-phosphate synthase in Escherichia coli: use of the T7 promoter

5-Enolpyruvylshikimate-3-phosphate (EPSP) synthase, the productof the Escherichia coli aroA gene, has been overproduced inE.coli BL21(DE3) under the control of the T7 gene 10 promoterand ribosome binding site, to a level of {small tilde}50% oftotal cell protein. EPSP synthase is the primary target of thepost-emergence herbicide, glyphosate, commonly known as Roundup^TM.A simple two step purification is described, which results in99% pure homogeneous protein (as determined by PAGE). The integrityof the protein has been compared with previously characterizedprotein from .E.coli AB2829(pKD501) by determination of itskinetic parameters, N-terminal protein and DNA sequences, aminoacid analysis and ¹³C-NMR spectroscopy. This new overproducingstrain readily provides the gram quantities of highly pure proteinrequired for NMR studies of the active site and the developmentof novel time-resolved solid-state NMR techniques currentlyunderway in this laboratory.     

FA and tocopherol composition of Vietnamese oilseeds

Seeds of 40 oilseed species from 23 different plant families (Brassicaceae, Cucurbitaceae, Fabaceae, Sapindaceae, Malvaceae, Gnetaceae, Clusiaceae, Bruseraceae, Ranunculaceae, Convolvulaceae, Amaranthaceae, Tiliaceae, Basellaceae, Solanaceae, Umbelliferae, Labiatae, Compositae, Theaceae, Euphorbiaceae, Caesalpiniaceae, Sapotaceae, Anacardiaceae, and Connaraceae) grown in Vietnam were analyzed for oilseed oil content, FA, and vitamin E. The seed oil content varied between 0.2 g/100 g for Mangifera indica and 75.7 g/100 g for Calophyllum inophyllum, whereas only nine seeds contained more than 40% oil. The tocopherol content ranged from 26 (Sapindus mukorossi) to 9361 mg/kg (Litchi chinensis). In nine seed oils unusual FA such as conjugated, cyclopropenoic, or epoxy FA were found.     

Influence of precursors on the formation of 3‐MCPD and glycidyl esters in a model oil under simulated deodorization conditions

To find new ways for reducing the potential of palm oil to form 3‐monochloropropane‐1,2‐diol (3‐MCPD) and glycidyl esters during refining it is helpful to know more about the influence of different precursors like diacylglycerols (DAGs) and monoacylglycerols (MAGs), lecithin, and chlorine containing compounds. After adding increasing amounts of the different precursors to a model oil obtained by removal of polar compounds from crude palm oil and heating the mixture under standardized conditions to 240°C for 2 h the contents of 3‐MCPD and glycidyl esters were analyzed according to the standard procedure of DGF C‐VI 18 (10). DAGs and MAGs were found to increase the potential of palm oil to form 3‐MCPD and glycidyl esters, but refined lecithin showed no influence. Sodium chloride as well as tetra‐n‐butylammoniumchloride (TBAC) led to higher contents of the esters. Whereas the addition of TBAC raised the amount of glycidyl esters as well as 3‐MCPD esters, sodium chloride largely raised the amount of 3‐MCPD esters. An addition of 5 mmol of sodium carbonate/kg model oil spiked with sodium chloride reduced the amount of glycidyl esters almost completely; the 3‐MCPD esters were reduced by 50%. About 1 mmol sodium hydrogen carbonate/kg oil reduced both 3‐MCPD and glycidyl esters almost completely. Practical applications : For the mitigation of the formation of 3‐MCPD esters and related compounds in refined edible oils, it is helpful to know more about the effect of different possible precursors. Using a broader data basis, it is possible to adopt the oil processing but especially the choice of the raw material to the demands of the market for lower contents of the esters in the refined products.     

Fullerene-functionalized carbon nanotubes as improved optical limiting devices

We report the synthesis, characterization and optical limiting behavior of a nanohybrid built by grafting C₆₀-fullerenes on carbon nanotubes (CNTs). The nonlinear optical limiting properties of the CNT-C₆₀ complex were investigated at wavelengths where C₆₀ does not absorb. We found that the nanohybrid had superior performances to those of CNTs and fullerenes, either taken individually or as a mixture. This enhanced optical limitation of the nanohybrid suggests not only cooperative but also synergistic effects between the two carbon forms. A mechanism involving higher excitonic states of the CNTs formed by Auger recombination of low energy excitons is proposed.     

Comparison of different methods for the determination of the oil content in oilseeds

The investigation and assessment of the oil content of oilseeds are important criteria, especially for the oil milling trade. Standard methods for the determination of the oil content of oilseeds are very time consuming, with extraction periods of 4 to 8 h. Three different oilseeds—rapeseed, sunflower, and soybean—are extracted by supercritical fluid extraction (SFE), accelerated solvent extraction, microwave-assisted extraction, solid fluid vortex extraction, and Soxtherm, and the results are compared with the result of the German Fat Science Society (DGF) standard method B-I 5 (87). Besides, the extracts are analyzed regarding the content of tocopherols as a parameter for mild extraction conditions and the content of diglycerides and free fatty acids as parameters for the content of more polar lipids. The results of the determination of the oil content under optimal conditions are comparable with the results of the DGF standard method B-I 5 (87). There are no significant differences between the different methods. The content of tocopherols is dependent upon the extraction method and the type of oilseed. The highest content is obtained by SFE. The content of diglycerides and free fatty acids varied according to the oilseed.     

Structural evolution at short and medium range distances during crystallization of a P2O5-Li2O-Al2O3-SiO2 glass

Li₂O-Al₂O₃-SiO₂ (LAS) glass-ceramics have important industrial applications and bulk nucleation is usually achieved by using nucleating agents. In particular, P₂O₅ is an efficient agent in glasses containing a low level of Al₂O₃ but its role in the first stages of nucleation is not well established. In this study, we combine structural investigations from local to mesoscales to describe the structural evolution during crystallization of LAS glass-ceramics. Local environment is probed using ²⁹Si and ³¹P MAS-NMR, indicating organization of P in poorly crystallized Li₃PO₄ species prior to any crystallization. To better understand the detailed nanoscale changes of the glass structure, ³¹P-³¹P DQ-DRENAR homonuclear correlation experiments have been carried out, revealing the gradual segregation of P atoms associated with the formation of disordered Li₃PO₄. Small-angle neutron scattering data also show the apparition of nanoscale heterogeneities associated with Li₃PO₄ species upon heating treatments and allow the determination of their average sizes. These new structural information enhance our understanding of the role of P in nucleation mechanisms. Nucleation is initiated by gradual change in P environment implying P segregation upon heating treatments, forming disordered Li₃PO₄ heterogeneities. The segregation of P atoms enables the precipitation of meta- and disilicate phases.     

Nanoscale Phase Separation in Lithium Niobium Silicate Glass by Femtosecond Laser Irradiation

Understanding the phase transformation in glass and the morphology of related nanostructure after femtosecond laser irradiation is of great importance for fabricating functional optics, in which glass crystallization is involved to obtain nonlinear optical properties. We report on the crystallization inside lithium niobium silicate glass induced by fs laser irradiation. Energy‐dispersive X‐ray spectroscopy coupled to scanning transmission electron microscopy (STEM/EDS) and transmission electron microscopy confirm a nanoscale phase separation whereby LiNbO₃ crystals are embedded in lamella‐shaped frames of amorphous SiO₂. The obtained nanostructure may have applications in fabricating second‐order nonlinear optical devices.