June 30th 2020
Tropical plants could provide clean label starch solution.
The international starch production sector for the food industry is somewhat restricted in the use of chemically modified starches due to country-specific regulations. Therefore, concentrated efforts are needed to identify starch sources with functional characteristics that are similar to chemically modified starches. From this perspective, the potential of five unconventional tropical food plant species is discussed: Canna edulis, Cyperus esculentus, Dioscorea bulbifera, Hedychium coronarium, and Xanthosoma sagittifolium. These tropical food plants can be grown using rustic agronomic management and have high productivity and easily extractable starchy tubers, roots, or rhizomes, which may open possibilities for the substitution of these native starch sources for chemically modified starches in food products.
Starch is the main reserve substance in plants, and it stands out as an abundant, nontoxic, renewable, and low-cost food ingredient. Starch accounts for about 80–90% of all polysaccharides present in human foods. Billions of dollars are spent annually worldwide on the marketing of starch products that serve a wide range of industrial segments, and starches are a major component in food product applications, as either ingredients or food additives.
Corn, potato, wheat, and cassava starches are the most widely used starches in the food industry, serving as thickeners, colloid stabilizers, gelling and volume agents, adhesives, moisture retainers, texturizers, and fat substitutes . In their native form, applications for starches are restricted because they usually have unwanted functional characteristics. They produce thin, elastic, and cohesive pastes, mainly due to their high hygroscopicity, rapid swelling, loss of viscosity, high tendency to retrograde, low shear strength, and heat treatments.
To overcome these limitations, modification processes are often employed. Chemical, physical, enzymatic, or a combination of these processes are currently employed to obtain customized starch products that meet the requirements for specific food applications.
Chemically modified starches are the most widely used. However, the use of new chemical reagents in starch modification is restricted by country-specific regulations that have increasingly stringent limits related to consumer and environmental protections and occupational safety. As a result, the food industry has been looking for new ways to modify starches or for native starches that have functional characteristics of interest, such as high paste clarity and freeze-thaw stability. In this context, both the food industry and farmers are increasingly interested in the identification and development of plants that produce native starches with physicochemical characteristics similar to those of modified commercial starches.
Unexplored tubers, roots, rhizomes, bulbs, and corms from tropical plants are emerging as important alternative sources for the starch industry, which could replace chemically modified starches and open new starch markets. In addition, temperate regions have limitations in their ability to cultivate a large variety of starchy tropical plant species due to climatic and environmental factors, creating the promising potential for growth of these species in tropical regions.