1,720,970 research outputs found
Effetti della aggiunta di cenere alle acque di vegetazione delle olive destinate allo spargimento su suolo agrario
No full textThe controlled spreading on agricultural soil, allowed by Italian regulations, seems at the moment, especially in marginal lands, the best method for olive mill waste water (AV) disposal. The decrease of phenolic substances, with antimicrobial and phytotoxic properties, could reduce potential negative effects on environment and crops. A possible easy way of reducing these substances in the AV could be the addition of ashes obtained by combustion of plants. In order to check this possibility, laboratory tests were made by using a solution obtained from frozen olives treated in a way like the processing for oil extraction. To samples of this solution ashes were added; then, after standing, phenols were periodically determined. For phenols analysis by the use of Folin–Ciocalteu reagent a simplified method was used. These compounds were also separated into two groups: mono-phenols and orto-diphenols by a non destructive method by using strong cation exchanger resins saturated with ferric ions, where orto-diphenols (or similar compounds), but not simple monophenols, were adsorbed. The analyses shoved that ashes caused an appreciable decrease of the content of the total phenols in the tested solutions and, especially, of orto-diphenols, which are those having bigger phytotoxic activity. This means that the biodegradation of the AV could be improved by the controlled addition of ashes. If these do not contain toxic elements and if they are obtained from plants grown in the same soils where the spreading is made, the AV treated with this by-product could be seen as a resource because of the return to soil of nutritive elements absorbed by plants
Detection of flavonoids in some Mediterranean plants.
No full textDue to nutritional and healthy properties, minor fruits obtained from wild or cultivated plants in the Mediterranean area are used in various traditional food products. But, as the harvesting and processing of these fruits are often not easy, plants which play an important role in the landscape, environment and soil preservation can remain underutilized. However, these plants also contain valuable compounds with biological activity and chemical characteristics which could make their cultivation and manufacturing advantageous. Among such compounds, polyphenols and especially flavonoids are of considerable interest for potential medical and industrial utilizations.
This paper reports experiments carried out for the recognition of these compounds in plants as mulberry, pomegranate and strawberry-tree in order to evaluate, beyond the use of the fruits in the food industry, the suitability of their extraction and so also of the growing, management and processing of these plant
Evaluation of the effects of roasting on chestnut flour
No full textDue to healthy and organoleptic properties of the chestnuts, nowadays, food products obtained from these nuts are increasingly important and various traditional recipes with chestnuts have been rediscovered. A simple cake of the past times, appreciated by children but at present not very well-known, was prepared by pressing chestnut flour in a little metal container, which was then heated until the flour became lightly brown-coloured. For such a purpose a thimble for sewing was suitable. By this way, a little and crumbly solid product, with an unmistakable aroma, was obtained. It was the result of chemical and physical changes caused by heat in the chestnut flour, partly similar to the modifications which take place in other flours, such as the rice flour, by effect of heating and partly due to peculiar components present in the chestnut flour. In order to carry out a preliminary study on such modifications, pressed samples of whole chestnut flour were heated until beginning of the roasting in such a way to imitate the preparation of the above mentioned cake. In a similar way were treated samples of rice flour after the addition of solutions extracted from chestnut flour with hexane, ethyl acetate, ethanol, water. By comparing aromatic and chemical characteristics of the samples before and after heating, a qualitative, preliminary estimate was made both of the effects of roasting on particular components present in the chestnut flour and of the way to separate them from the flour
Separazione di composti fenolici dell'idromele e loro confronto con quelli del miele di origine
No full textThe content and composition of phenols are among the main characteristics which differentiate the hydromel from other alchoholic beverages. These compounds in the hydromel are substantially those present in the honey from which it is made by dilution and fermentation. The comparison of phenolic compounds of hydromel with those of honey, where they are present as flavonoids aglicones and free phenolic acids, may give information both on the origin of this alchoholic beverage and the evolution of these compounds during the fermentation, clarification and storage. In this paper is presented a simple analytical method for the extraction and separation of phenolic compounds of honey and hydromel, based on solid phase extraction and interaction of phenolic compounds with metal ions
Adsorption and release of phenolic compounds on ion exchange columns saturated with metal ions. (A preliminary study)
No full textIn order to evaluate the effects of interactions between phenolic compounds and metal ions fixed on cation exchange resins (SCX), standard solutions of phenolic compounds in ethanol were eluted through ion exchange columns for solid phase extraction (SPE) saturated with the ions Fe(III),Al(III), or Cu(II). The compounds which form complexes with these ions remained adsorbed on these columns, whereas the others were released. The subsequent elution with the mixture 1:1 ethanol/1N sulphuric acid then allowed the extraction also of adsorbed phenols. These results suggest the possibility of separating, by elution through ion exchange columns, classes of phenolic compounds of food products on the basis of their structural characteristics and of the cations present in ion exchange resins
Separation of walnut kernel polyphenols
No full textPhenolic substances, the main group of natural antioxidants of walnut, contribute remarkably to nutritional and organoleptic properties of the kernel. There are however some difficulties in the study of such substances due to presence at the same time of many of them in the nut, so their whole characterisation needs many standards and expensive instruments. This work describes a new methodology for studying phenolic substances of walnut, founded on the interactions of of phenolic compounds with metal ions situated in the exchange places of ion exchange resins. The method allows easier recognition and characterisation of these substances by separating them in classes on the basis of their structural characteristics and of the cations present in the ion exchange resins
Adsorption on cation exchange resins saturated with ions H+, Al3+, Fe3+ as a potential way to separate grups of phenolic compounds
No full text- …
