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In order to explore the effects of different oil production processes on the variety of flavor substances in peanut oil. In this study, headspace solid phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC-MS) were used to detect the volatile flavor substances in peanut oil prepared by the ancient, cold-pressed, hot-pressed methods and the self-made unbaked and baked aqueous enzymatic method respectively. The results showed that there were 41, 39, 41, 56 and 56 volatile substances in peanut oil measured by ancient method, cold press, hot press, unbaked and baked water enzymatic method respectively. In addition, according to the analysis of the contents of various substances, it was found that aldehydes had a higher variety in the five kinds of peanut oil, and had a greater influence on the flavor. Alcohols mainly exist in peanut oil prepared by cold press and unbaked water enzymatic method. Pyrazines and phenyl-containing substances mainly existed in peanut oil prepared by ancient method, hot pressing and baking water enzymatic method, and contributed greatly to their flavor. Ester substances mainly affect the flavor of peanut oil by ancient pressing and enzymatic method without baking. The proportion of acid in peanut oil by heat pressing and baking water enzymatic method was higher, which had a greater influence on its flavor. Ketones, ethers, alkanes, alkenes and alkynes account for a small proportion and have a high taste threshold, so their contribution to the five peanut oils is relatively low.

The volatile flavor compounds from cold-pressed peanut oils which were pretreated by pulsed electric field (PEF), microwave (MW) and ultrasonic wave (UW) respectively were concentrated by HS-SPME and analyzed by GC-MS. The types and relative contents of aldehydes, ketones, pyrazines and other volatile flavor substances in peanut oil were studied. The results indicated that a total of 97 volatile flavor substances were identified from the tested samples. And the cold-pressed peanut oil prepared by different pretreatment methods had different volatile flavor substances. In PEF-pretreated-cold-pressed peanut oil, acetoin was the characteristic flavor compound which has a pleasant aroma of butter. Among the volatile flavor substances of MW-pretreated-cold-pressed peanut oil, pyrazines and pyrroles have nutty and roasty flavor, and this type of cold-pressed peanut oil had flavor characteristics similar to those of hot-pressed peanut oil. The volatile flavor substances of UW-pretreated-cold-pressed peanut oil were mainly acids, showing a smell of oleic acid. Hence, there were significant differences in the effect of pretreatment on volatile flavor substances of cold-pressed peanut oil, and different flavors of cold-pressed peanut oil can be obtained by changing the pretreatment method.

Multi-walled carbon nanotubes (MWNTs) were incorporated into a linear low-density polyethylene (LLDPE) matrix through using screw extrusion and injection technique. The effect of different weight percent loadings of MWNTs on the morphology, mechanical, and thermal of LLDPE/MWNTs nanocomposite had been investigated. It was found that, at low concentration of MWNTs, it could uniformly disperse into a linear low-density polyethylene matrix and provide LLDPE/MWNTs nanocomposites much improved mechanical properties. Thermal analysis showed that a clear improvement of thermal stability for LLDPE/MWNTs nanocomposites increased with increasing MWNTs content.

The cDNA sequences of 26 starch synthesis genes were identified in common wheat (Triticum aestivum L.), and their transcript levels were measured using quantitative real-time RT-PCR to assess the function of individual genes and the regulatory mechanism in wheat endosperm. The expression patterns of 26 genes in wheat endosperm were classified into three groups. The genes in group 1 were richly expressed in the early stage of grain development and may be involved in the construction of fundamental cell machinery, synthesis of glucan primers, and initiation of starch granules. The genes in group 2 were highly expressed during the middle and late stages of grain development, and their expression profiles were similar to the accumulation rate of endosperm starch; these genes are presumed to play a crucial role in starch production. The genes in group 3 were scantily expressed throughout the grain development period and might be associated with transitory starch synthesis. Transcripts of the negative transcription factor TaRSRl were high at the early and late stages of grain development but low during the middle stage. The expression pattern of TaRSRl was almost opposite to those of the group 2 starch synthesis genes, indicating that TaRSRl might negatively regulate the expression of many endosperm starch synthesis genes during grain development. Key words: starch, starch synthesis genes, TaRSRl, transcript, Triticum aestivum. Les sequences des ADNc de 26 genes codant pour des amidon synthetases ont ete identifiees chez le ble tendre (Triticum aestivum L.) et l'abondance de leurs transcrits a ete mesuree par RT-PCR quantitatif en temps reel afin d'evaluer la fonction des genes individuels ainsi que le mecanisme de regulation au sein de l'albumen du ble. L'expression des 26 genes au sein de l'albumen a permis de les classer au sein de trois groupes. Les genes du groupe 1 etaient fortement exprimes dans les premiers stades de developpement du grain et pourraient etre impliques dans l'etablissement de la machinerie cellulaire fondamentale, la synthese des glucanes d'amorcage et l'initiation des granules d'amidon. Les genes dugroupe 2 etaient fortement exprimes lors des stades mitoyens et tardifs de developpement du grain et leur profil d'expression etait semblable au taux d'accumulation d'amidon dans l'albumen. Les auteurs postulent que ces genes jouent un role crucial dans la production d'amidon. Les genes du groupe 3 etaient faiblement exprimes tout au long du developpement du grain et pourraient etre impliques dans la synthese transitoire de l'amidon. Le transcrit du facteur de transcription negatif TaRSRl etait abondant lors des stades precoces et tardifs de developpement du grain, tandis qu'il etait peu abondant au cours des stades mitoyens. Ainsi, l'expression de TaRSRl etait pratiquement a l'oppose de l'expression des genes du groupe 2, ce qui indique que TaRSRl pourrait reguler negativement l'expression de plusieurs genes codant pour des amidon synthetases au cours du developpement du grain. [Traduit par la Redaction] Mots-cles: amidon, genes codant pour des amidon synthetases, TaRSRl, transcrit, Triticum aestivum., Introduction Starch is a primary source of carbohydrate in the endosperm of cereals, including wheat, rice, and maize, and in recent decades many studies have attempted to provide a better [...]