?-Glucans are major hemicelluloses in shoot shells of the woody bamboo Guadua chacoensis

PAULA VIRGINIA FERNÁNDEZ; MARÍA EVELINA CAPARRÓS FRENTZEL; MARINA CIANCIA

San Martín, Provincia de Buenos Aires

Simposio; 3rd Argentinian Symposium on Glycobiology; 2019

Universidad Nacional de San Martín

-Glucans are major hemicelluloses in shoot shells of the woody bamboo Guadua chacoensis.Fernández, PV; Caparrós Frentzel, ME; Ciancia, M.vfernand@agro.uba.arWoody bamboos are perennial plants with very high rates of growth. Bamboo shoots are the new culms, valorized by their nutritional properties. Bamboo shoot shells are thick leaves that protect the growing structures. They comprise up to 60% of the shoot weight, so they represent an important byproduct from shoot processing. Guadua Kunth (Poaceae) is a genus native from the American continent that has not been studied in detail. Sequential extraction (hot water, Na2CO3 and KOH solutions) was carried out on the alcohol insoluble residue obtained from shoot shells of G. chacoensis. As expected for grasses, major yields were observed in alkaline, hemicellulosic extracts (1M and 4M KOH), which represented together 47% w/w of the cell wall material. Usually, glucuronoarabinoxylans ?GAX- are the major hemicellulosic polymers, however, in this case, β-glucans showed to be the predominant polysaccharides. The four major alkaline extracts (1MA, 1MB, 4MA and 4MB) were further separated into a minor water soluble fraction and a major water insoluble fraction. Water soluble fractions probed to be rich in GAX, and they also contained significant amounts of mixed linkage glucans (ratio 4Glc:3Glc from 1:0.05 to 1:0.31). On the other hand, insoluble fractions comprised mostly xyloglucans (XG). On this basis, XG is the major hemicellulose in this specialized structure, although being a polysaccharide commonly reported as a minor component in Type-II cell walls.