Sunflower extraction meal (SEM) is an economically interesting protein source. During alkaline extraction of proteins, the presence of chlorogenic acid (CQA) in the meal gives rise to the formation of o-quinones. Reactions with nucleophiles present in proteins can lead to green discoloration. Although such reactions have been known for a long time, there is a lack of information on the chemical nature of the reaction products. SEM and model systems consisting of amino acids and CQA were subjected to alkaline treatment and, for comparison, to oxidation of CQA by polyphenoloxidase (PPO). Several green trihydroxy benzacridine (TBA) derivatives were tentatively identified in all samples by UHPLC-DAD-MS/MS. Surprisingly, in alkaline-treated samples of particular amino acids as well as in SEM, the same six TBA isomers were detected. In contrast, the enzymatically oxidized samples resulted in only three TBA derivatives. Contrary to previous findings, neither peptide nor amino acid residues were attached to the resultant benzacridine core. The results indicate that the formation of TBA derivatives is caused by the reaction between CQA quinones and free NH 2 groups. Further research is necessary to elucidate the structure of the addition products for a comprehensive evaluation of food and feed safety aspects.

The objective of this study was to characterize the phenolic composition of Brazilian pepper (Schinus terebinthifolius Raddi) exocarp extract. Using UHPLC-DAD-MS/MS analysis, four anthocyanins, three biflavonoids, gallic acid, and two types of hydrolyzable tannins (galloyl glucoses, galloyl shikimic acids) were tentatively identified. The structure of the so far unknown 7-O-methylpelargonidin 3-O-β-D-galactopyranoside was elucidated by 2D NMR. Within the group of gallotannins, galloyl shikimic acids with uncommon degrees of galloylation (tetra- to hexagalloyl shikimic acids) were detected. Among the biflavonoids, I3',II8-biapigenin (amentoflavone), I6,II8-biapigenin (agathisflavone), and II-2,3-dihydro-I3',II8-biapigenin were identified, which have already been described for Anacardiaceae. From the results of the present study together with previous findings on the phenolic profile of other Anacardiaceae plants, it is concluded that 7-methoxylated flavonoids are a chemotaxonomic trait frequently found in this family.

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Pigments of pericarp and pulp of pink guava (Psidium guajava L. cv. 'Criolla') were investigated to elucidate the profile and the accumulation of main carotenoids during four stages of fruit ripening by using HPLC-DAD and APCI-MS/MS analysis. Seventeen carotenoids were identified, and changes in their profile during fruit ripening were observed. The carotenoids all-trans-β-carotene, 15-cis-lycopene, and all-trans-lycopene were present in all ripening stages, but all-trans-lycopene was found to be predominant (from 63% to 92% of total carotenoids) and responsible for the high lipophilic antioxidant capacity determined by spectrophotometric assays. By using light and transmission electron microscopy, the development of chromoplasts in pericarp and pulp was demonstrated. The accumulation of all-trans-lycopene and all-trans-β-carotene coincided with the development of large crystals; the chromoplasts of pink guava belong, therefore, to the crystalline type.

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The objectives of this work were to determine the phenolic profile of Schinus terebinthifolius and Schinus molle fruits and to develop a reliable method for the differentiation of these two similar spices both known as pink pepper. Anthocyanins, biflavonoids and gallotannins, some of which are reported for the first time in these species, were identified by UHPLC-UV/vis-MS/MS. Consideration of the relative and absolute amounts of phenolics as well as indicator compounds from 18 samples revealed that the relative amounts of anthocyanins and biflavonoids are the most trustworthy parameters. Principal component analysis and cluster analysis (CA) allowed a grouping of the samples according to their species, showing that the anthocyanins are most important for the identification of species. As a result, authentication of the two Schinus species can be accomplished by UHPLC analysis of the relative amounts of anthocyanins combined with CA.