Comprehensive Characterization of the Polysaccharide Composition and Xyloglucan Architecture of Four Berry Fruits and Their Macroscopic Fruit Components

Abstract

For the structural characterization of the fiber polysaccharides of berry fruits in general and their xyloglucan architecture in particular, chokeberries, cranberries, raspberries, and red currants were subjected to monomer analysis after acid hydrolysis (HPAEC-PAD), methylation analysis (GC-FID/MS), and a specific xyloglucanoligosaccharide profiling approach (HPAEC-PAD/MS). The characterization was carried out on the whole fruit and on macroscopic fruit components: the fruit pulp and press residues, the latter being separated into seeds and seedless residues (mainly epidermal and vascular tissues). The complementary data provide a comprehensive insight into the cell wall polysaccharide architecture of these frequently consumed and fiber-rich plant foods. In addition to their substantial structural variability, their cell walls were found to be less rich in xyloglucans and galacturonic acid containing polysaccharides than expected for fruits of dicotyledonous plants. Furthermore, the botanically diverse fruit types were classified with respect to their xyloglucan architecture in accordance with taxonomy: chokeberries, raspberries, and red currants exhibited XXXG-type fucogalactoxyloglucans. Differently, cranberries demonstrated a unique diversity of both arabino- and fucogalactoxyloglucans.