Search results for "Chemical composition"

From Norway Spruce Bark to Carbon Foams : Characterization, and Applications

2020

Fresh bark from spruce Picea abies was milled and extracted with hot water. The extracts were purified in a number of steps in order to get tannin-extracts pure enough to prepare tannin-based carbon foams. The chemical composition of the extracts were analyzed. The foams were maturated and thermally treated to obtain desired properties, such as specific surface area, porosity, and compressive strength. It was possible to produce carbon foams even if they contained carbohydrate impurities. Differences in the properties of the carbon foams such as compressive strength, specific surface areas, and pore size distributions might be related to the compositions of the extracts. The foams were fina…

Selective incorporation of dissolved organic matter (DOM) during sea ice formation

2013

This study investigated the incorporation of DOM from seawater into >2 day-old sea ice in tanks filled with seawater alone or amended with DOM extracted from the microalga, Chlorella vulgaris. Optical properties, including chromophoric DOM (CDOM) absorption and fluorescence, as well as concentrations of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), dissolved carbohydrates (dCHOs) and dissolved uronic acids (dUAs) were measured. Enrichment factors (EFs), calculated from salinity-normalized concentrations of DOM in bulk ice, brine and frost flowers relative to under-ice water, were generally >1. The enrichment factors varied for different DOM fractions: EFs were the lowest fo…

Spectroscopic analysis of hot-water- and dilute-acid-extracted hardwood and softwood chips

2017

Hot-water and dilute sulfuric acid pretreatments were performed prior to chemical pulping for silver/white birch (Betula pendula/B. pubescens) and Scots pine (Pinus sylvestris) chips to determine if varying pretreatment conditions on the original wood material were detectable via attenuated total reflectance (ATR) infrared spectroscopy. Pretreatment conditions varied with respect to temperature (130 °C and 150 °C) and treatment time (from 30 min to 120 min). The effects of the pretreatments on the composition of wood chips were determined by ATR infrared spectroscopy. The spectral data were compared to those determined by common wood chemistry analyses to evaluate the suitability of ATR spe…

Effect of Seasonal Storage on Single-Stem Bark Extractives of Norway Spruce (Picea abies)

2021

Increasing the net value of forestry side-streams has both ecological as well as economic benefits for emerging biorefining industries. Spruce bark represents one of the nature’s abundant sources of valuable extractives. In this study, the impact of storage on the quality and quantity of Norway spruce (Picea abies) extractives was examined as a function of storage time, environmental conditions and season (i.e., winter or summer). The bark from stored spruce saw logs was extracted with an accelerated solvent extractor (ASE) at 120 °C with hexane and water. The produced extracts were analysed qualitatively and quantitatively by gas chromatography with a flame ionisation detector (GC-FID) and…

Corrigendum to “Gas chromatographic–mass spectrometric investigation of the chemical composition of beebread” [Food Chem. 115 (2009) 1056–1063]

2016

Comparative Chemical Composition and Bioactivity of Opuntia ficus‐indica Sanguigna and Surfarina Seed Oils Obtained by Traditional and Ultrasound‐Ass…

2018

This study investigates the seed oils obtained from two different varieties of Opuntia ficus-indica (Sanguigna and Surfarina) growing in Sicily, Italy. Soxhlet and ultrasound-assisted extraction procedures are used to obtain the seed oils. The fatty acid profile, γ-tocopherols, carotenoid content, and the bioactivity in terms of the antioxidant effects (using ABTS, DPPH, FRAP, and β-carotene bleaching tests), and carbohydrate-hydrolysing enzyme inhibitory activity (α-amylase and α-glucosidase) are determined. The extraction procedure does not significantly affect the fatty acid composition of the oil, but it does affect the tocopherol and carotenoid contents, as well as the antioxidant and …

Guava: phytochemical composition of a potential source of antioxidants for cosmetic and/or dermatological applications

2017

Made available in DSpace on 2018-11-28T14:21:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-01-01. Added 1 bitstream(s) on 2019-10-09T18:26:25Z : No. of bitstreams: 1 S1984-82502017000200612.pdf: 803011 bytes, checksum: 199524e8d40cccb25490594ec61b3ed8 (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) PADC-FCF-UNESP Fundação para o Desenvolvimento da UNESP (FUNDUNESP) Guava (Psidium guajava L.) is a native fruit of the American tropics with commercial applications for its taste, flavor and aroma. Numerous pharmacological uses have been described for it, such as the antiseptic effect of it…

Chemical Composition, In Vitro Antitumor and Pro-Oxidant Activities of Glandora rosmarinifolia (Boraginaceae) Essential Oil

2018

The biological properties of essential oils have been demonstrated in the treatment of several diseases and to enhance the bioavailability of other drugs. In natural habitats the essential oils compounds may play important roles in the protection of the plants as antibacterials, antivirals, antifungals, insecticides and also against herbivores by reducing their appetite for such plants or by repelling undesirable others. We analyzed by gas-chromatography mass spectrometry the chemical composition of the essential oil of aerial parts of Glandora rosmarinifolia (Ten.) D.C. Thomas obtained by hydrodistillation and verified some biological activities on a panel of hepatocellular carcinoma cell …

Prickly Pear By-Product in the Feeding of Livestock Ruminants: Preliminary Investigation

2020

Simple Summary The question of sustainability of animal nutrition has become a popular topic. The gains made by recycling safe, yet otherwise valueless, by-products and wastes from human food and fiber production (green feeds) may lessen the competition between humans and animals for crops and decrease the environmental impact of food production. In this context, prickly pear by-product, which results from Opuntia ficus-indica (L.) Mill. fruits processed for juice extraction, could be an optimum by-product to ruminant feeding. This study evaluates the nutritional characteristics and its stability during storage using potassium metabisulfite as a preservative agent. This preliminary investig…

Tunisian Milk Thistle: An Investigation of the Chemical Composition and the Characterization of Its Cold-Pressed Seed Oils

2017

In this study, milk thistle seeds growing in different areas in Tunisia were cold pressed and the extracted oils were examined for their chemical and antioxidant properties. The major fatty acids were linoleic acid (C18:2) (57.0%, 60.0%, and 60.3% for the milk thistle seed oils native to Bizerte, Zaghouan and Sousse, respectively) and oleic acid (C18:1) (15.5%, 21.5%, and 22.4% for the milk thistle seed oils originating from Bizerte, Zaghouan and Sousse, respectively). High performance liquid chromatography (HPLC) analysis showed the richness of the milk thistle seed oils (MTSO) in α-tocopherol. The highest content was recorded for that of the region of Zaghouan (286.22 mg/kg). The total ph…