Study of extraction conditions for phenolic compounds from Strawberry fruits

Strawberries are an important source of phytochemicals, namely vitamins and phenolic compounds such as anthocyanins and tannins with antioxidant properties [1]. The yield and phenolic content of natural extracts are dependent on the conditions used for extraction [2]. In the present work three different types of extracting solutions (methanol, ethanol:water and aceton:water), two times of extraction (15 and 60 min) and three ratios of solid/solvent (5/25, 5/50 and 5/100 g/mL) were tested in order to evaluate the efficiency of the extraction of phenolic compounds. Phenolic compounds were determined by Folin-Ciocalteu method [3]. Each assay was performed in triplicate. Regarding the extraction solution, it was possible to observe a slight tendency towards a higher efficiency of acetone:water (AcO:H2O, 60:40), but the differences mioght not be statistically significant. A longer time of contact, 60 min as opposed to 15 min, did not show advantages in the yield of extraction. Considering the factors under study, the results obtained showed that volume of extraction solution was the parameter that most influenced the values obtained. Using a higher volume lead to an increase in the amount of phenolic compounds extracted, in a more pronounced way for 15 min of extraction. For a volume of 25 mL the amount of phenolic compounds quantified ranged from 2.13-2.41 mg GAE/g, and increased 30-68% when it was used 50 mL of solution. Using 100 mL of solution, it was extracted twice as double of phenolic compounds. In case of 60 min, the amount of phenolic compounds quantified in samples obtained with 25 mL of solution ranged from 2.32-2.97 mg GAE/g, and increased for 2.43-4.27 mg GAE/g and 3.98-4.68 mg GAE/g when was used 50 and 100 mL, respectively.

Composting of different agro-food wastes: Effects of the phenolic and lignocellulosic fractions on greenhouse gases emissions

Currently, society faces a number of challenges related to the large amounts of organic wastes generated and accumulated by the increasing expansion of agroindustrial activities1. Most of these wastes are rich in lignocellulosic compounds, which represents a major fraction of all plant biomass (of above 90%), so, its degradation is crucial for global carbon cycle2. These organic wastes may be introduced directly on agriculture sector as soil organic amendment, however, these might contain phytochemicals, such as phenolic compounds which may introduce toxic effects to soil and to beneficial organisms. Transformation and degradation of these renewable organic wastes into composts (COMPOSTING) is a possible solution for these problems and an environmentally friendly processes that allows make use of natural resources efficiently3. The main potential handicap is generation and emission of greenhouse gases such as carbon dioxide (CO2 ), methane (CH4 ) and nitrous oxide (N2O) and another ones which may led serious problems like nitric oxide (NO) and ammonia (NH3) 4. For this reason, quantification of GHG emissions from composting and finding possible relations with the chemical and structural composition of the wastes used is crucial to the development of technologies for mitigating emissions and should help to make decisions concerning waste management.

Comparative analysis of volatile and phenolic composition of alternative wood chips from cherry, acacia and oak for potential use in enology.

The aim of present work was to investigate the phenolic and volatile composition of cherry, acacia, and oak (from different species) wood chips. By the use of HPLC-DAD 18 different phenolic compounds were detected and quantified while for volatile composition, 33 different compounds were detected by GC-MS. In general, wood samples from oak species showed the higher number of phenolic compounds detected, while cherry wood samples showed the lowest levels. In addition, some individual phenolic compounds were detected, specifically in some wood samples, such as robinetin in acacia woods and naringenin in cherry wood. For volatile composition, cherry wood chips samples showed the lowest volatile composition followed by increasing order by acacia, French, Portuguese and American wood chip samples. Oak wood chip samples from American species showed the highest volatile content, as a result of high levels of several specific compounds (furfural, 5-methyfurfural, β-methyl-γ-octalactones, guaiacol, vanillin and siringaldehyde).