Development of a physicochemical method to quantify the extracellular liquid volume: Application to the transformation of cassava into gari

Abstract

In fresh vegetal materials, liquid is mostly located in cells. During processing, this liquid is distributed in the entire vegetal matrix volume including exctracellular volume. According to its location, it will be more or less available for physico-chemical mechanisms that takes place during processing of vegetal matrices. This availability greatly influences the quality of the final products. This work consisted in developing a method for determining the quantity of extracellular liquid in a cell-component food matrix. The method developed is spectrophotometric-based and consists in adding a known mass of polymer (poly(4-styrenesulfonate) sodium salt, PSS) to a rasped vegetal material and defining its concentration in the supernatant separated from the solid phase. The PSS molar mass prevents it from penetrating into plant cells. The PSS concentration measured makes it possible to calculate the extracellular liquid volume. The method validation and its application to rasped and processed (fermentation, pressing) cassava makes it possible to obtain results in agreement with those obtained with other methods.