Incidence of autochthonous Argentinean mixed starter cultures in ripening of slurry cheese models

The effect of three mixed autochthonous starter cultures in ripening profiles of experimental semihard goat cheeses was evaluated under controlled microbiological conditions. Enterococcus faecium ETC3 and ETC6, Lactobacillus plantarum ETC17 and L. rhamnosus ETC14 were used. Combination of all strains showed the highest level of water soluble nitrogen fraction and total free amino acids (TFAA) at ripening day 1, the lowest level of phosphotungstic acid nitrogen soluble fraction and TFAA at ripening day 64 and the highest global impression. Principal component analyses were performed to establish amino acid profiles relations in the samples.     

生物医用Ti6Al4V/xTiN复合材料的腐蚀与腐蚀磨损行为

用固相烧结法制备Ti6Al4V/xTiN(x=0,5,10,15,体积分数,％)复合材料,研究材料的腐蚀与腐蚀磨损行为及其与显微组织和显微硬度的关系.采用37℃ 和模拟体液模拟人体环境.结果表明,当TiN含量为15％时,氮(N)固溶到钛(Ti)晶格中使α-Ti稳定化,该显微组织的改变使Ti64基体的硬化效应达到58％....     

Using contextual information to improve land use classification of satellite images in central Spain

Abstract

The classification accuracy obtained from the classification of satellite images using pixel-by-pixel conventional methods can be improved if the contextual information is considered jointly with the spectral information in the same strategy of classification. A computer program has been developed to implement a contextual classifier algorithm. The accuracy improvement was evaluated and tested in two pilot zones of central Spain. Two indices were defined in order to analyse the homogeneity effect produced by the contextual classifier.     

Identification of and relationships among a number of teinturier grapevines that expanded across Europe in the early 20th century

Background and Aims: The arrival in Europe of powdery mildew (1845), phylloxera (1863) and mildew (1878) led to great interest in grapevine varieties less sensitive to these diseases, but still producing good quality wine. Standing out was a small group of teinturier vines that were once much appreciated for the colour their grapes brought to wines because of their pigmented skins and pulp. The aim of the present work was to determine the true identity of nine teinturier grapevine varieties that were collected from different vine‐growing areas of northern and north‐western Spain under local names. Methods and Results: This study combined the ampelographic characterisation of the leaves and the use of molecular markers (simple sequence repeats) to allow some of these varieties to be identified, the existence of a number of synonyms to be established and the relationships among some of these grapevines to be determined. Conclusions: Most of the teinturier varieties studied are related to the internationally known cultivars Morrastrel Bouschet, Alicante Bouschet, Petit Bouschet and Jacquez. The origin of the teinturier variety collected with the local name Folla Redonda is still unknown. Significance of the Study: The information provided by this research helps define the origin of commercially important teinturier varieties and may be helpful in their identification and selection for cultivation in certain vine‐growing areas.     

Particle size distribution and morphological changes in activated carbon‐metal oxide hybrid catalysts prepared under different heating conditions

In catalysis processes, activated carbon (AC) and metal oxides (MOs) are widely used either as catalysts or as catalyst supports because of their unique properties. A combination of AC and a MO in a single hybrid material entails changes not only in the composition, microstructure and texture but also in the morphology, which may largely influence the catalytic behaviour of the resulting product. This work is aimed at investigating the modifications in the morphology and particle size distribution (PSD) for AC‐MO hybrid catalysts as a result of their preparation under markedly different heating conditions. From a commercial AC and six MO (Al₂O₃, Fe₂O₃, ZnO, SnO₂, TiO₂ and WO₃) precursors, two series of such catalysts are prepared by wet impregnation, oven‐drying at 120ºC, and subsequent heat treatment at 200ºC or 850ºC in inert atmosphere. The resulting samples are characterized in terms of their morphology and PSD by scanning electron microscopy and ImageJ processing program. Obtained results indicate that the morphology, PSD and degree of dispersion of the supported catalysts are strongly dependent both on the MO precursor and the heat treatment temperature. With the temperature rise, trends are towards the improvement of crystallinity, the broadening of the PSD and the increase in the average particle size, thus suggesting the involvement of sintering mechanisms. Such effects are more pronounced for the Fe, Sn and W catalysts due to the reduction of the corresponding MOs by AC during the heat treatment at 850ºC.     

APPLICATION OF MULTIVARIATE STATISTICAL ANALYSES TO THE STUDY OF FACTORS AFFECTING WHITE WINE VOLATILE COMPOSITION

ABSTRACT

The influence of different storage conditions on the volatile composition of young white wine was evaluated during 1 year of storage. The wine was bottled and stored under different conditions of temperature, position and illumination. During storage, a significant increase in total content esters (mainly due to the increase in ethyl butyrate, ethyl acetate and diethyl succinate) and total content acids was detected. Also total content alcohols and carbonyl compounds decreased during storage. Storage time, temperature and illumination have a significant effect on esters content, whereas carbonyl compounds are affected by temperature, and alcohols content is affected by illumination. Stepwise linear discriminant analysis was applied to the experimental data. The results showed that the samples were well classified as a function of storage temperature. On the other hand, a certain trend was observed when the wine samples were classified according to storage time. The samples corresponding to two and four months of storage were well differentiated from the rest.

PRACTICAL APPLICATIONS

From a sensory point of view, the aroma influences greatly the quality of wines. The loss of aromatic characteristics in young white wine, as well as browning, take place over a variable period of time which ranges from one month to several years, depending on wine type and storage conditions. Assessment of possible factors affecting the useful lifespan of young white wine is of great interest for the wine making industry. Knowing the chemical composition of wine, specifically aromas, and its evolution relating to different storage and preservation conditions is an important tool in quality control.