Physiological deterioration of cassava roots

Abstract

Rapid post-harvest physiological deterioration of cassava roots (Munihot esculentu Crantz) appears to be due essentially to wound responses, comparable to those observed in other plant storage organs. The wound responses observed include: increased activity of phenylalanine ammonia lyase, an enzyme associated with phenol biosynthesis; increased activity of peroxidase and polyphenol oxidase; formation of phenolsipolyphenols including leucoanthocyanidins, catechins, scopoletin and condensed tannins, and often the formation of a wound periderm. In cassava, the responses did not remain localised at wound surfaces in roots when held at low storage humidity but spread through the roots causing a discolouration of the vascular tissue and storage parenchyma. Roots stored at high humidity showed a more typical wound response with localised production of phenols and periderm formation.

Biochemical and bioactive phytonutrients changes in tissues of two cultivars of fresh-cut cassava in stick form under refrigerated storage

“…However, the PAL activity increases during the storage period, according the regression test. The same behavior was also observed in the studies by RICKARD (1985), PLUMBLEY &RICKARD (1991) andMEDEIROS (2009). The increased synthesis of PAL is an expected response in fresh-cut products, such as shear response to cutting (CAMPOS-VARGAS et al, 2005), since the PAL is a key enzyme in the synthesis of phenolic compounds involved in the response system to injury (HAHLBROCK & SCHEEL, 1989).…”

Large-Scale Proteomics of the Cassava Storage Root and Identification of a Target Gene to Reduce Postharvest Deterioration

“…The potential of cassava as a food and industrial crop, however, is still limited because of rapid postharvest physiological deterioration (PPD) of the root (Wenham, 1995;Sayre et al, 2011). PPD is induced by mechanical damage during harvesting and handling operations (Booth, 1976;Rickard, 1985), and progression depends on cassava genotypes and storage conditions (Sanchez et al, 2006). The blue-black discoloration of the vascular parenchyma that develops during PPD and that is followed by a general discoloration of the storage parenchyma, as well as physiological and biochemical changes, ultimately render the roots unpalatable (Beeching et al, 1998).…”

Extending Cassava Root Shelf Life via Reduction of Reactive Oxygen Species Production

“…Manipulation of these conditions can delay or hasten the process. For example, storage at 10°C and 80% humidity, waxing, and careful avoidance of physical damage can all delay PPD significantly (Rickard, 1985;Plumbley and Rickard, 1991;Wenham, 1995). While storage conditions and practices can go a long way in controlling PPD, the development of long-shelf-life varieties of cassava remains the most desirable strategy, since no postharvest intervention would be required.…”