Phenolic Profile of Asturian (Spain) Natural Cider

The polyphenolic composition of natural ciders from the Asturian community (Spain), during 2 consecutive years, was analyzed by RP-HPLC and the photodiode-array detection system, without previous extraction (direct injection). A total of 16 phenolic compounds (catechol, tyrosol, protocatechuic acid, hydrocaffeic acid, chlorogenic acid, hydrocoumaric acid, ferulic acid, (-)-epicatechin, (+)-catechin, procyanidins B2 and B5, phloretin-2¢-xyloglucoside, phloridzin, hyperin, avicularin, and quercitrin) were identified and quantified. A fourth quercetin derivative, one dihydrochalcone-related compound, two unknown procyanidins, three hydroxycinnamic derivatives, and two unknown compounds were also found. Among the low-molecular-mass polyphenols analyzed, hydrocaffeic acid was the most abundant compound, representing more than 80% of the total polyphenolic acids. Procyanidins were the most important family among the flavonoid compounds. Discriminant analysis was allowed to correctly classify more than 93% of the ciders, according to the harvest year; the most discriminant variables were an unknown procyanidin and quercitrin

Study of the Phenolic Profile of Cider Apple Cultivars at Maturity by Multivariate Techniques

Phenolic compounds in 46 Spanish cider apple varieties were determined by RP-HPLC with direct injection. Several pattern recognition procedures, including principal component analysis (PCA), linear discriminant analysis (LDA), and partial least squares (PLS-1), were applied to the data in an attempt to classify the samples into bitter and nonbitter categories. Reliable decision rules were obtained by both LDA and PLS-1. LDA achieved 91.3 and 85.7% correct classification respectively, for internal and external evaluation of the model

Straight access to highly fluorescent angular indolocarbazoles via merging Au- and Mo-catalysis

A straightforward and efficient synthesis of the two less explored types of indolocarbazoles has been developed. Two different processes for the carbazole nucleus preparation, a gold-catalysed regioselective cyclization followed by the dioxomolybdenum-catalysed version of Cadogan reductive cyclization, enables the sequential construction of two carbazole cores. The procedure features total regioselectivity and high overall yields. The required starting α-indol-3-ylalkyl propargylic alcohols are easily and efficiently accessed from commercially available reagents. In addition, the photoluminescent properties of two indolo[2,3-c]carbazoles, with fluorescence quantum yields around 0.7, have been studied.Junta de Castilla y León and FEDER (BU291P18) and Ministerio de Ciencia e Innovación and FEDER (CTQ2016-75023-C2-1-P