Isolation and characterisation of the two main cell-wall types from guava ( Psidium guajava L.) pulp

Abstract

Cell-wall materials (CWM) were extracted separately from the endocarp and mesocarp portions of guava fruit (cv. Suprême) by the sodium deoxycholate-(phenol-acetic acid-water) extraction procedure, and further fractionated by enzymatic and physical means into fragile parenchymatous (PAR) and hard stone (STO) cell walls. Mesocarp contained ∼ 90% of the total CWM of the edible part (excluding skin and seeds) of guava. ∼74% of which were stone cells, while endocarp was relatively richer in parenchymatous tissue. PAR cell walls had similar composition in both endocarp and mesocarp, and were made up of ∼55–60% of neutral polysaccharides (mainly cellulose, xyloglucan, xylan, arabinan, and arabinogalactans of both types I and II) associated with weakly methyl-esterified galacturonan. STO cell walls were strongly lignified, secondarised elements, ∼ 50% consisting of equivalent amounts of cellulose and acetylated xylan.