Results 1 - 10 of 497
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[en] An alternative as to offer higher stable and easy handling than fresh fruit is in powdered form, as long as the process used to obtain it ensures a high quality product. The objective of this study was to compare the bioavailability of the vitamin C of a juice prepared from powdered grapefruit obtained by freeze-drying and by spray-drying. A trial was conducted with 11 healthy volunteers. A relative increase of 1,4 – 25,8 % of blood serum vitamin C concentration was quantified after juices intake, with no significant differences (p>0.05) due to the process used to obtain the powder. (Author)
[en] The south of Brazil is one of the largest producers of grapes, and as a consequence there is a large generation of waste that can be used as a profitable alternative source. The aim of this work was to obtain and evaluate oil and the flour for human consumption from the residue of cold-pressed Bordô from conventional and organic grape seeds in a winery in the south of Brazil. By cold pressing, the organic oil obtained higher yield. The quality parameters of the conventional oil were better, although with a higher index of peroxides and iodine. The conventional flour presented better results for quality and centesimal composition, mainly due to the higher fiber content and the fact that it did not contain high acidity or humidity. Therefore, the results of products were similar for both crops, but the conventional one was better. However, traces in the agrochemical residue analysis found for the conventional crop might better qualify the organic products.
[es]El sur de Brasil es uno de los mayores productores de uva, por lo que existe una gran generación de residuos que se pueden utilizar como fuente alternativa y rentabilizar. El objetivo de este trabajo es obtener y evaluar los aceites y las harinas, para nutrición humana, del residuo de prensado en frío de las semillas de uva convencionales y orgánicas de Bordô en una bodega del sur de Brasil. Al presionar en frío, el aceite orgánico se obtuvo con gran rendimiento. Los parámetros de calidad del aceite convencional fueron mejores, aunque con un mayor índice de peróxidos y de yodo. La harina de semillas convencionales presentó mejores parámetros de calidad y composición centesimal, principalmente debido al mayor contenido en fibra y no tuvieron acidez alta o humedad. Por lo tanto, los resultados de los productos fueron similares para ambos cultivos, pero el convencional fue mejor. Por otro lado, el análisis de trazas de residuos agroquímicos podrían calificar los productos como orgánicos.
[en] Grape canes are the main agro-wastes from vineyards. This work studied the antioxidant activities of the defatted methanolic extracts (ME) of canes from 11 genotypes: 5 Vitis vinifera widely known cultivars and 6 Chinese wild varieties from three species (V. amurensis, V. davidii, and V. pentagona) and the antioxidant activities of the ME’s chloroform fractions (CF), ethyl acetate fractions (EAF) and water fractions (WF). Among ME and its three fractions, EAF’s total phenolic contents (TPC) and total flavonoid contents (TFC) were the highest, at 586 mg/g of gallic acid equivalent and 320 mg/g of quercetin equivalent, respectively. The antioxidant power of the fractions/extracts was in the order EAF > ME > WF > CF, based on the DPPH radical-scavenging power and ferric-reducing antioxidant activity, while the order was EAF > CF > WF >ME based on the β-carotene-linoleic acid bleaching activity. Methanolic extracts demonstrated the strongest Fe2+-chelating activity. The antioxidant activities of the extracts/fractions generally correlated with the TPC and TFC in all assays, except with the Fe2+-chelating test. Grape canes from V. davidii had the highest TPC, TFC and antioxidant activities compared with those from other grape species. Catechin, epicatechin and trans-resveratrol were the predominant phenolic components of fractions/extracts. In light of these valuable bioactivities, grape canes from annual pruning practice considered as waste material have good commercial potential for utilization as a promising natural antioxidant in the food, pharmaceutical and cosmetic industries, given its low cost and availability in large amounts. (Author)
[en] Anthocyanins are a class of phenolic compounds that contribute to the color of red grapes and have shown nutraceutical properties for human health. UVC light irradiation has been proved to increase phenolic compounds such as stilbenes, but its effect on anthocyanins has not been reported. The aim of this work was to identify the best treatment conditions of UVC light irradiation on post-harvest berries of Malbec (M), Cabernet Sauvignon (CS) and Tempranillo (T) for anthocyanin increments. Grape berries were irradiated with 240 W at 20 and 40 cm from the light source, for 30, 60 and 120 seconds. Both, irradiated and control grapes were stored on darkness at 20 C degree until anthocyanin extraction with methanol/ClH. HPLC analysis were performed and nine anthocyanins were quantified. UVC light irradiation modified the anthocyanin profile of the three cultivars. All the glucoside anthocyanins derivates and peonidin-acetyl-glucoside, as well as total anthocyanins were increased when CS berries were exposed to UVC for 120 s at 40 cm. This suggests that UVC stimulated the entire biosynthetic pathway. The anthocyanin content of the control berries was always higher than the treatments with UVC on M and T, making necessary to evaluate less rigorous conditions for these varieties. (authors)
[en] Grape pomace is an agro-industrial by-product from the production of must (grape juice) by pressing whole grapes. In order to evaluate the seeds and skins of the grape pomace, it must first be dried and then separated in a screen machine. The drying of pomace is an important and necessary process for the optimum separation of seeds. The main purpose of this study was to determine the optimum drying process for obtaining high-quality grape seed oil. In this research, open air and solar energy drying methods were compared in terms of water activity, total bacterial and mold-yeast count, along with the chemical and fatty acid compositions of pressed grape residues. Oleic acid and linoleic acid contents ranged from 16.56-16.96% and 71.45-71.96%, respectively. Antioxidant activities ranged from 2.33-2.80 μmol trolox/g. The results showed that the drying methods did not decrease the nutritional quality of grape residues and prevented microbial growth by decreasing water activity to below 0.60.
[es]El orujo de uva es un subproducto agroindustrial de la producción de mosto (jugo de uva) al prensar las uvas enteras. Para poder evaluar las semillas y las pieles del orujo de uva, primero debe secarse y luego separarse mediante una máquina de tamizado. El secado del orujo es un proceso importante y necesario para una separación óptima de las semillas. El objetivo principal de este estudio fue determinar el proceso de secado óptimo para obtener aceites de semillas de uva de alta calidad. En este trabajo, los métodos de secado al aire libre y la energía solar de los residuos de uva prensados se compararon en términos de actividad de agua, recuento total de bacterias y moho, así como la composición de ácidos grasos. Los contenidos de ácido oleico y linoleico variaron entre 16,56-16,96% y 71,45-71,96%, respectivamente. Las actividades antioxidantes variaron entre 2,33-2,80 μmol trolox/g. Los resultados mostraron que los métodos de secado no disminuyeron la calidad nutricional de los residuos de la uva y evitaron el crecimiento microbiano al disminuir la actividad del agua por debajo de 0,60.