The Relationship between Methods of Making Cassava Flour and Coumarin Formation during Drying

Abstract

The susceptibity of fresh cassava roots to deterioration under tropical conditions has seriously limited its full utilization. The roots are extremely perishable so that a few days after harvest, deterioration may set in, and are consequently rendered unfit for edible purpose¹⁾.Several methods have been devised to preserve the roots, but processing into dried cassava chips, or cassava flour is one of the cheapest and most utilized methods of preservation²⁾. Further, it has been noted that cassava flour can be utilized as a good replacement-source for noodle³⁾, bread, cake and some fermented foods⁴⁾ such as "puto". Thus, it has become important to elucidate the factors related to the production of good quality cassava flour. On the other hand, it has been clarified that the bluish fluorescent components, that is, the coumarin derivatives such as scopoletin, esculin and scopolin are formed in cassava tissue, inresponse to artificial or natural injury, or in relation to physiological and microbial deteriorations occurring during storage.^5)-8) We assumed that such stress metabolites as the coumarin derivatives might be fbrmed in larger amounts in the cut-injured tissue in the course of drying of thet issue since not only cut-injury but also drying must supply a stress to the living tissue cells, and lesser amounts might be produced when the tissue cells die in a shorter period as in fast drying resulting in cassava flour of better quality. Further, we thought that the TLC assay of the above fluorescent components in cassava flour might be useful to evaluate the food quality of the flour. This paper deals with the relation of various methods of making cassava flour with the intensity of the fluorescent components in the flours.