Effect of calcium on rheological properties of Abelmoschus esculentus (okra) pod polysaccharide and its application in Annona squamosa

Abstract

The fruit softening seriously affected the quality of Annona squamosa, and the edible coating combined with exogenous calcium had a positive effect on inhibiting the softening of A. squamosa. In this paper, the rheological properties of C-AeP-P solution and the effect of Ca2+ on the rheological properties of the solution were studied. Based on this, the indicators of fruit hardness, freshness and plumpness were used to monitor the softening effect of A. squamosa. The results show that: C-AeP-P solution showed non-Newtonian shear-thinning behavior over the range of 0.2-1.0%. With the increase of C-AeP-P concentration, the apparent viscosity and solids like properties increased. After the addition of Ca2+, C-AeP-P had apparent differences on apparent viscosity. The G′ and G″ of C-AeP-P were increased with increasing oscillation frequency. C-AeP-P and C-AeP-P+Ca2+ treatment can slow down rapidly decline of fruit hardness, increase of soluble solid content, loss of water, change peel color and regulate the expression of key enzyme genes AI and Ni. It was concluded that the coating treatment of C-AeP-P alleviates the adverse effects of quality changes during storage, so as to improve the quality and prolong the shelf life of A. squamosa.