Search

Abstract: Plums (Prunus domestica L.) of a greengage variety, from South–East of Portugal, are used to produce a traditional candied product, “Ameixa d’Elvas”, which has a Protected Designation of Origin, recognised by the European Union. To obtain a good texture quality in candied plums, it is necessary to define accurate maturation parameters. Parameters such as the total soluble solids (TSS), titratable acidity (TA), TSS/TA, and pH are not always suitable for this purpose. In order to find a more reliable maturation parameter, plums were collected during the commercial harvesting period, in two orchards, Vila Viçosa and Cano in different years (2003 and 2005). Total polysaccharides (PS) and uronic acids (UA) were quantified in the alcohol-insoluble residues (AIR) of pulp. In all harvests, the content of polysaccharides and uronic acids present in the AIR increased as the maturity of the fruits progressed. To the dataset that comprised the TSS, TA, TSS/TA, pH, PS, and UA measured in these plums, a linear discriminant classifier was applied to obtain a reliable parameter to predict fruit quality upon candying. The models built showed errors of lack of fitness of 0.005% for the content of UA in the AIR and 0.8% for PS, which contrasted with the errors of 17%, 21%, 17%, and 11%, for the TSS, TA, ratio TSS/TA, and pH, respectively. Considering that the variability associated with the content of PS was higher than that observed in UA estimation, and the easy and fast determination of UA, it is proposed that the UA content in AIR be used as a reliable harvesting maturity parameter, complementary to TSS and/or TA, to obtain a high quality candied product. An easy and quick laboratory methodology is proposed for the determination of the UA in plums. [Copyright &y& Elsevier]

Sea salt is a handmade food product that is obtained by evaporation of seawater in saltpans. During the crystallisation process, organic compounds from surroundings can be incorporated into sea salt crystals. The aim of this study is to search for potential volatile markers of sea salt. Thus, sea salts from seven north-east Atlantic Ocean locations (France, Portugal, Continental Spain, Canary Islands, and Cape Verde) were analysed by headspace solid-phase microextraction combined with comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry. A total of 165 compounds were detected, ranging from 32 to 71 compounds per salt. The volatile composition revealed the variability and individuality of each salt, and a set of ten compounds were detected in all samples. From these, seven are carotenoid-derived compounds that can be associated with the typical natural surroundings of ocean hypersaline environment. These ten compounds are proposed as potential volatile markers of sea salt., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Monovarietal white wines from Maria Gomes and Bical Portuguese Bairrada varieties were prepared according to different maceration and pectic enzyme clarification procedures. The polysaccharide-rich extracts, obtained by wine concentration, dialysis, and lyophilization, were fractionated by graded ethanol precipitation. A wide range of fractions rich in polysaccharides were obtained. Using the spectral region between 1200 and 800 cm(-)(1) of the FTIR spectra of the wine polysaccharide dry extracts, using PCA and CCA chemometric methods, it was possible to discriminate the extracts on the basis of their polysaccharide composition. Moreover, it was possible to identify the wine-making processes involved and their influence on the wine polysaccharides. Furthermore, a calibration model using a PLS1 was proposed for the quantification of mannose in the samples obtained by precipitation with 60% ethanol aqueous solutions. This information will allow an expeditious assessment and monitoring of the polysaccharide composition and modifications that occur during the wine-making processing and evolution.