abstract
Instant coffee was prepared and fractionated into higher (>100 kDa), medium (5-10, 10-30, 30-100 kDa) and lower (1-5, <1 kDa) molecular weight fractions. Sugars and linkage composition characteristics of arabinogalactans and galactomannans were recovered in all fractions. Also, amino acid analysis performed after hydrolysis showed similar compositions in all fractions. On the contrary, free chlorogenic acids and caffeine were only detected in the lowest molecular weight fraction (<1 kDa). A direct relationship between the melanoidins browning index and the molecular weight was observed. The fractions obtained were incubated in vitro with murine spleen lymphocytes in order to evaluate their possible immunostimulatory abilities. The surface expression of CD69 (early activation marker) on different lymphocyte sub-populations showed that the fraction with 1-5 kDa was able to induce activation of B-lymphocytes. This was the only fraction to induce B-lymphocyte activation, since all the other fractions failed, even when higher concentrations were used. (C) 2014 Elsevier Ltd. All rights reserved.
keywords
CHEMICAL-CHARACTERIZATION; SPENT COFFEE; ARABINOGALACTAN-PROTEIN; MAILLARD REACTION; SIDE-CHAINS; MELANOIDINS; POLYSACCHARIDES; HEALTH; MODEL; PREMELANOIDINS
subject category
Chemistry; Food Science & Technology; Nutrition & Dietetics
authors
Passos, CP; Cepeda, MR; Ferreira, SS; Nunes, FM; Evtuguin, DV; Madureira, P; Vilanova, M; Coimbra, MA
our authors
Dmitry Evtyugin
Associate Professor with Aggregationacknowledgements
Thanks are due to Science and Technology Foundation, Ministry of Education and Science (FCT, Portugal), European Union, QREN, FEDER and COMPETE for funding the QOPNA research unit (Project PEst-C/QUI/UI0062/2013; FCOMP-01-0124-FEDER-037296). Claudia Passos was supported by a post-doc Grant by FCT (SFRH/BDP/65718/2009).