Molecular features of protein and starch in African rice relate to their processing behavior

Research and development interventions in the African rice sector mainly focused on increasing farm-level production, whereas little attention was paid to processing and quality enhancement issues, which play major roles in the definition of the value of rice and rice-derived product.
The aim of this study was to investigate the starch and protein properties of rice varieties popularly cultivated in Africa in order to identify which varieties could be most suitable for the development of various specific food products. These products may include pasta, pasta-like products, and a large variety of ready-to-eat rice-based foods. For this reason a number of African varieties and species representative of various locales and produced in commercially significative amounts were selected also according to distinctive physical and chemical parameteres.
Starch properties and protein content in individual samples were characterized by standard chemical methods. In selected cases, structural organization of starch was investigated by measuring susceptibility to selective enzymatic activities [1]. Viscoamilography was used to investigate the possible relationships between structural features and the pasting behavior of starch [2]. Information on the protein pattern in selected varieties was gathered by electrophoresis, whereas the accessibility of specific residues and of specific regions that may be involved in determining the properties of products was addressed by appropriate reagents and spectroscopic approaches [3].
The approaches presented here seem able to provide useful insights as for the intrinsic structural characteristics of starch and proteinsin various African rice varieties. Further studies will verify whether this information will be able to define proper processing and the possible end uses of some of the materials investigated here.
This work was supported by the “New Products“ Project from the Global Rice Science Partnership (GRiSP).
References
[1] Barbiroli A, Bonomi F, Casiraghi MC, Iametti S, Pagani MA, Marti A (2013). Process conditions affect starch structure and its interactions with proteins in rice pasta. Carbohyd. Polym. 92, 1865–1872.
[2] Marti A, Seetharaman K, Pagani MA (2010). Rice-based pasta: a comparison between conventional pasta-making and extrusion- cooking. J. Cereal Sci., 52, 3, 404-409.
[3] Bonomi F, D’Egidio M G Iametti S, Marengo M, Marti A, Pagani MA, Ragg EM (2012). Structure–quality relationship in commercial pasta: A molecular glimpse. Food Chem. 135, 348–355.