Elena Falqué

In vitro antioxidant properties of crude extracts and compounds from brown algae

Research on the bioactives from seaweeds has increased in recent years. Antioxidant activity is one of the most studied, due to the interest of these compounds both as preservatives and protectors against oxidation in food and cosmetics and also due to their health implications, mainly in relation to their potential as functional ingredients. Brown algae present higher antioxidant potential in comparison with red and green families and contain compounds not found in terrestrial sources. In vitro antioxidant chemical methods, used as a first approach to evaluate potential agents to protect from lipid oxidation in foods, confirmed that the brown algae crude extracts, fractions and pure components are comparatively similar or superior to synthetic antioxidants. Particular emphasis on the fucoidan and phlorotannin polymeric fractions is given, considering variations associated with the species, collection area, season, and extraction and purification technologies.

Differentiation of white wines by their aromatic index

Wines from four Galician white varieties (Albariño, Loureira, Treixadura and Dona Branca) with 1992 to 1995 vintages have been analysed, in order to obtain their characterisation by the aromatic index. Monoterpenes, higher alcohols, ethyl esters, fatty acids, acetates, volatile phenols and heavy sulphur compounds were analysed by gas chromatography alone and together with mass spectrometry. Flavour compositions were similar for each wine obtained from grapes harvested in different years. Comparisons between odour unit values (OUV) from each wine variety and from these vintages were similar. However, odour profiles of Galician wines from these years were clearly differentiated. A correct differentiation could be achieved between samples elaborated with different varieties, when principal component and linear discriminant analysis were applied to the OUV data.

Antimicrobial Action of Compounds from Marine Seaweed

Seaweed produces metabolites aiding in the protection against different environmental stresses. These compounds show antiviral, antiprotozoal, antifungal, and antibacterial properties. Macroalgae can be cultured in high volumes and would represent an attractive source of potential compounds useful for unconventional drugs able to control new diseases or multiresistant strains of pathogenic microorganisms. The substances isolated from green, brown and red algae showing potent antimicrobial activity belong to polysaccharides, fatty acids, phlorotannins, pigments, lectins, alkaloids, terpenoids and halogenated compounds. This review presents the major compounds found in macroalga showing antimicrobial activities and their most promising applications.

Recovery and Concentration of Antioxidants from Winery Wastes

: Grape and wine byproducts have been extensively studied for the recovery of phenolic compounds with antioxidant activity and a variety of biological actions. The selective recovery and concentration of the phenolic compounds from the liquid phase separated from further diluted winery wastes has been proposed. Adsorption onto non ionic polymeric resins and further desorption with ethanolic solutions was studied. Several commercial food grade resins were screened with the aim of selecting the most suited for the practical recovery of phenolic compounds with radical scavenging activity. Under the optimized desorption conditions (using Sepabeads SP207 or Diaion HP20 as adsorbents and eluting with 96% ethanol at 50 °C) a powdered yellow-light brown product with 50% phenolic content, expressed as gallic acid equivalents, was obtained. The radical scavenging capacity of one gram of product was equivalent to 2–3 g of Trolox.

Algal proteins, peptides and amino acids.

Abstract: In this chapter data on the composition of proteins, peptides and amino acids from macro and microalgae are presented. The specific chemical and physicochemical methods of protein and amino acid analysis are discussed. Information on the variability in the contents and activities caused by seasonal and environmental factors is described. In addition, the biological activities and the potential applications as functional food ingredients are discussed.

Note: Effects of Oak Wood on the Aromatic Composition of Vitis vinifera L. var. treixadura Wines

Treixadura wines from the 1998 vintage were obtained from traditional vinification in a winery. After alcoholic fermentation, the wine was subjected to ageing in oak barrels for three months. One part of the wine is placed in barrels of American oak and the other part in French oak (Allier oak). Wine stored simultaneously in a stainless steel tank was used as a control. Chemical composition and volatile compounds of wines were analysed. There were no appreciable differences in alcohol and tartaric acid among the wines stored under different conditions, but differences were observed in pH, total and volatile acidity, reducing sugars, malic and lactic acids. Ageing in oak barrels resulted in an increase in volatile acidity and Folin—Ciocalteu index, and a decrease of free and total sulphur dioxide. Various monoterpenes, norisoprenoids, hexenols, sulphurs, volatile phenols, acetals and lactones increase their content notably when aged in barrels of both American and French oak. On the other hand, some acetates, ethyl esters and fatty acids were present in higher concentrations in the wine stored in stainless steel tank. Sensory results indicated that the wine aged in French (Allier) oak was better scored than when aged in American oak, as it provided subtle and delicate nuances of wood, which did not mask the fruity aroma of the Treixadura wine but contributed to its aromatic complexity.

Recent developments on the extraction and application of ursolic acid. A review

Ursolic acid (UA) is a pentacyclic triterpenoid widely found in herbs, leaves, flowers and fruits; update information on the major natural sources or agro-industrial wastes is presented. Traditional (maceration, Soxhlet and heat reflux) and modern (microwave-, ultrasound-, accelerated solvent- and supercritical fluid) extraction and purification technologies of UA, as well as some patented process, are summarized. The great interest in this bioactive compound is related to the beneficial effects in human health due to antioxidant, antimicrobial, anti-inflammatory, hepatoprotective, immunomodulatory, anti-tumor, chemopreventive, cardioprotective, antihyperlipidemic and hypoglycemic activities, and others. UA may augment the resistance of the skin barrier to irritants, prevent dry skin and could be suitable to develop antiaging products. The development of nanocrystals and nanoparticle-based drugs could reduce the side effects of high doses of UA in organisms, and increase its limited solubility and poor bioavailability of UA which limit the potential of this bioactive and the further applications. Commercial patented applications in relation to cosmetical and pharmaceutical uses of UA and its derivatives are surveyed.

Identification of key odorants related with high quality touriga nacional wine

High quality Touriga Nacional (TN) wines are characterised by a fruity-citric aroma described as sweet and of fresh citrus, evoking the bergamot fruit (Citrus bergamia). By sensory analysis the identification of the most important descriptors were found. Among 18 descriptors 3 were selected: ‘bergamot-like’ aroma, ‘orange-like’ and ‘violet’. A GCO of an extract of a typical TN wine allowed the identification of three related odorant zones ZO1, ZO2 and ZO3 showing bergamot-like odours. By AEDA the importance of ZO2 was confirmed, this odorant zone corresponded to the presence of linalool and linalyl acetate. Results from a similarity test showed that the highest value was observed when linalool alone was added. Results obtained from the analysis of several red wines from different varieties show that terpenols are present in higher amounts in wines from the TN variety. These compounds are most likely the indicator/trigger of the varietal aroma of TN wines.

Pressurized hot water extraction of β-glucans from Cantharellus tubaeformis

Cantharellus tubaeformis was processed by pressurized hot water extraction (80–240°C) with the aim of maximizing the extraction of oligomeric fractions, β‐glucans, and the in vitro antioxidant properties of the extracts. Increased severity of treatment enhanced the extraction yields above 62% at temperatures of 210ºC or higher, corresponding to the maximum β‐glucan yields. The highest antioxidant capacity was obtained at 170ºC, although the highest content of phenolic compounds was obtained at the highest severity studied. This hydrothermal treatment can be considered a suitable process to obtain extracts with antioxidant properties and rich in β‐glucans.

Effect of Different Types of Glass Container on Food Shelf Life

The main objective of this article is to develop an overview of the use of glass in food packaging. When combined with the appropriate closure, the glass jar or bottle provides an inert, hermetic, durable packaging medium for a wide variety of foods from dry powders to liquids, some of which are carbonated and packed under pressure, and products which are heat-sterilized. The transparency of glass allows consumers to see the product, yet variations in glass color can protect light-sensitive contents. Finally, glass packaging benefits the environment because it is reusable and recyclable.