Comparison of the eating quality of selected potato cultivars from two production regions in South Africa and a proposed classification system for the consumer

Abstract

The eating quality of South African potato cultivars has not been determined and described scientifically. By determining the eating quality of potato cultivars, appropriate culinary applications can be identified for the South African consumer, based on the scientific information obtained. With the compilation of a databank, comprised of the eating quality of potato cultivars available in South Africa, a classification system can be developed and proposed, similar to those available in other countries. In this study, the first objective was to determine, describe and compare the eating quality of potato cultivars from two production regions. The second objective of the study was to propose a classification system for potato cultivars for the South African consumer. The envisaged classification system will provide consumers with information regarding potato cultivars and serve as a guide to assist them with the selection of a suitable cultivar for a specific culinary application. For this quantitative study, the focus was on two potato production regions (Limpopo and the Eastern Free State), and three potato cultivars were selected, namely BP1, Mondial and FrutiLay (a processing potato with a high dry matter content). The study was conducted in two phases. Phase 1 involved a descriptive sensory evaluation performed by a trained sensory panel. Sensory descriptors for the sensory evaluation were identified and a lexicon was developed. A category scale was used to rate the sensory attributes. Objective evaluation was performed in Phase 2, which involved physical measurements of specific gravity, shear force resistance measurement and scanning electron microscopy. The eating quality of potatoes obtained from these two production regions was determined, described and compared. From the results obtained it is clear that the eating quality of one production region differs from the other, as different production factors such as growing and climatic conditions exist between the regions. It is evident that both sensory and objective evaluations need to be performed in order to determine the eating quality of the various potato cultivars, as one evaluation supports the other. In order to develop and propose a classification system for potatoes, a representative sample of potato cultivars is necessary. Therefore, seven different cultivars from the Eastern Free State region were evaluated and compared towards attaining this objective. A Partial Least Square regression modelling method was used to relate the sensory attributes and objective measurements, in order to propose a classification system for potato cultivars. Potato cultivars were grouped and suggested culinary applications were assigned to the various cultivars. The study confirms the valuable contribution of determining the eating quality of potato cultivars for the development of a proposed potato classification system for all production regions, in order to assist the South African consumer with suggested culinary applications for potato cultivars. This classification system would not only benefit the potato industry, but the South African consumer as well.