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Arabinose from arabinogalactan side chains was hypothesized as a possible binding site for chlorogenic acids in coffee melanoidins. To investigate this hypothesis, a mixture of 5- O -caffeoylquinic acid (5-CQA), the most abundant chlorogenic acid in green coffee beans, and (α1 → 5)- l -arabinotriose, structurally related to arabinogalactan side chains, was submitted to dry thermal treatments. The compounds formed during thermal processing were identified by electrospray ionization mass spectrometry (ESI-MS) and characterized by tandem MS (ESI-MS n ). Compounds composed by one or two CQAs covalently linked with pentose (Pent) residues (1–12) were identified, along with compounds bearing a sugar moiety but composed exclusively by the quinic or caffeic acid moiety of CQAs. The presence of isomers was demonstrated by liquid chromatography online coupled to ESI-MS and ESI-MS n . Pent 1–2 CQA were identified in coffee samples. These results give evidence for a diversity of chlorogenic acid–arabinose hybrids formed during roasting, opening new perspectives for their identification in melanoidin structures. [ABSTRACT FROM AUTHOR]

Abstract: Red wine is an important source of dietary intake of phenolic compounds with antioxidant activity that are related to the prevention of cardiovascular diseases and cancer. However, information concerning their specific release from this food matrix, although necessary to predict their bioavailability along the digestive tract, is still not clear. In this work, the interactions that can occur between the red wine polymeric material and anthocyanins were studied. For this purpose, the diffusion performance of nine anthocyanins through a dialysis membrane was evaluated in the presence and absence of the wine polymeric material. For each anthocyanin, a retention coefficient was calculated. Although in different extents, all anthocyanins were retained by the wine polymeric material. The higher retention coefficient was observed for coumaroyl and acetyl derivatives when compared with the non acylated anthocyanins. It is suggested that these associations are ruled by hydrophobic interactions. These results allow the prediction of a continuous and gradual dosage of wine anthocyanins, contributing to an extension in beneficial health properties upon ingestion. [Copyright &y& Elsevier]

Abstract: Peroxidase from olive fruit (Olea europaea L., cv Douro) in a black ripening stage was purified to electrophoretic homogeneity, resulting in four cationic and four anionic fractions. The anionic fractions accounted for 92% of recovered activity and showed molecular masses of 18–20kDa. The anionic fraction PODa4, the predominant fraction that comprised about 70% of total recovered activity, showed an isoelectric point of 4.4 and optimum pH and temperature of, respectively, 7.0 and 34.7°C, and apparent K m values of 41.0 and 0.53mM, for phenol and H2O2, respectively. From the activity-temperature profile, the denaturation temperature and the changes in enthalpy and heat capacity for unfolding of PODa4 were estimated as being, respectively, 36.5°C, 411.2 and −13.6kJmol−1 K−1. The activation energy for phenol oxidation by PODa4 was 99.1kJmol−1, corresponding to a calculated temperature coefficient (Q 10) of 4. The arabinose (39mol%) and galacturonic acid (38mol%) content of the carbohydrate moiety indicated the existence of pectic material in the purified PODa4 fraction. Co-migration of the carbohydrate with the protein band in the isoelectric focusing electrophoresis, points to PODa4 fraction as being a pectin type binding peroxidase. [Copyright &y& Elsevier]

Wine polymeric material (WPM), which includes polysaccharides, proteins, and polyphenolic compounds, interacts with anthocyanins. To determine the contribution of polysaccharides in these interactions, the diffusion performance of anthocyanins along a dialysis membrane was determined in the presence and absence of isolated mannoproteins (MP) and arabinogalactans (AG) from WPM. Furthermore, to estimate the extent of the interaction between WPM and polyphenolic compounds, the activation energy (E a ) required for their diffusion in the presence of WPM was determined. AG, generally more abundant than MP in wine, interact in a greater extent with anthocyanins, showing their relevant contribution for WPM/anthocyanins interactions. The E a for the diffusion of polyphenolic compounds in presence of WPM indicated the occurrence of interactions with relative weak to strong intensities (2.6–50.8 kJ/mol). As not all polyphenolic compounds were able to be released from WPM, stronger interactions, possibly by covalent linkages, are involved, providing new insights on WPM/polyphenolic compounds relationships. [ABSTRACT FROM AUTHOR]

An instant coffee fraction, rich in arabinogalactans, obtained by ultrafiltration, using 1 and 5 kDa membranes, has previously shown in vitro stimulatory activity on BALB/c mice spleen B lymphocytes. The compounds inducing lymphocytic activation were shown to elute, mainly near the void volume by size-exclusion chromatography, using Bio-Gel P6 (1–6 kDa). Treatment of the compounds with chymotrypsin, a digestive protease, did not affect the induced B lymphocyte activation. On the contrary, hydrolysis with an α- l -arabinofuranosidase, removing single terminally-linked arabinose residues, decreased the extent of B cell activation. The immunostimulatory activity of these compounds was also observed by in vitro experiments, using bone marrow-derived macrophages and dendritic cells as responders. Altogether, these results show the relevance of single arabinose residues, present at the non-reducing end of polymeric compounds, to the coffee stimulatory activity in cells mediating innate and acquired immunity. [ABSTRACT FROM AUTHOR]

Highlights: [•] Instant coffee compounds were fractionated by ultrafiltration. [•] Sugar linkage composition and amino acids were determined in all fractions. [•] The molecular weight was directly proportional to the amount of brown compounds. [•] Only the fraction of 1–5kDa presented a B-lymphocyte stimulatory activity. [ABSTRACT FROM AUTHOR]

Abstract: The volatile composition of ‘Bravo de Esmolfe’ (BE) apple was achieved by headspace-solid phase microextraction (HS-SPME) followed by gas chromatography–mass spectrometry (GC–qMS) analysis using fruits from two different rootstocks (PAJAM2 and MM106), different trees of each rootstock, and different sections of each tree (north and south). Fruits were harvested in the maturity state defined for this variety and then stored for four months at 4°C. During this period, analyses were made monthly. α-Farnesene was the compound found in the volatile profile of BE apple with the largest GC area. A large number of esters were also detected. Rootstocks, trees, and tree sections did not have statistical significance on the volatile composition of BE apples. However, the volatile composition changed throughout the storage period. The principal component analysis (PCA) allowed distinguishing between the apples obtained immediately after harvest and those stored for 4 months. In the first case, the volatile composition was related to the occurrence of aldehydes, aromatic hydrocarbons, and phenols and, in the second case, to esters and terpenoids. Ocymene, cymene, α-bergamotene, geranyl acetone, nerolidol, and ethyl 3-(methylthio)-propionate were identified for the first time in apples. This peculiar profile allows to propose them as varietal markers of BE apple variety. However, as this methodology has only been applied to BE apple, the occurrence of these compounds in other cultivars can not be excluded. [Copyright &y& Elsevier]