Cell wall polysaccharides from macauba pulp (Acrocomia aculeata L.): Fractionation and characterization of their chemical and rheological properties

Macauba fruit pulp (Acrocomia aculeata) is an emerging oil source. After de-oiling, the macauba pulp meal (MPM) offers a dietary fiber content of 40–50 %, which mainly comprises cell wall polysaccharides (CWP). The present work aimed to assess the potential of MPM as an innovative source of sustainable food polysaccharides. To this end, the macauba CWP were fractionated into water-soluble galactoglucomannans (21.7 %), calcium- and ester-bound pectins (3.4 %), loosely-bound xyloglucans (27.6 %), strongly-bound xylans (6.5 %), and a cellulose-rich fraction (39.3 %). The galactoglucomannans produced shear-thinning aqueous dispersions with an increase in consistency index from 3.03·10−2 to 3.58·101 Pa·sn by increasing the concentration from 1.0 to 5.0 %. The galactoglucomannans dispersions showed semi-dilute behavior, evidenced by relaxation times ranging from 1.24·10−2 to 1.17 s for concentrations from 2.5 to 10.0 %. Macauba pectins and xyloglucans showed weak gel behavior, with an increase in yield stress from 3.20·10−1 to 1.04·102 Pa and from 7.01·10−2 to 1.35·102 Pa for dispersions at 2.5 to 10.0 %, respectively. 2.5 to 5 times higher concentration of macauba polysaccharides is needed to obtain rheological behavior similar to guar and xanthan gum. The thickening and gelling properties of macauba CWP highlight their potential as thickeners and stabilizers for the food industry.