Mineral Composition of Malawian Cocoyam (Colocasia esculenta and Xanthosoma sagittifolium) Genotypes

Taro Roots: An Underexploited Root Crop

Taro (Colocasia esculenta) is a root crop that remains largely underutilized and undervalued despite its abundance and affordability. In comparison to other root vegetables, such as potatoes, yams, carrots, and cassava, taro stands out as a plentiful and low-cost option. As global hunger increases, particularly in Africa, it becomes essential to address food insecurity by maximizing the potential of existing food resources, including taro, and developing improved food products derived from it. Taro possesses a wealth of carbohydrates, dietary fiber, vitamins, and minerals, thereby making it a valuable nutritional source. Additionally, while not a significant protein source, taro exhibits higher protein content than many other root crops. Consequently, utilizing taro to create food products, such as plant-based milk alternatives, frozen desserts, and yogurt substitutes, could play a crucial role in raising awareness and increasing taro production. Unfortunately, taro has been stigmatized in various cultures, which has led to its neglect as a food crop. Therefore, this review aims to highlight the substantial potential of taro as an economical source of dietary energy by exploring the rich fiber, potassium, vitamin C, protein, and other micronutrient content of taro, and providing a foundation for the formulation of novel food products. Furthermore, this paper assesses the nutritional benefits of taro, its current utilization, and its antinutritional properties. It emphasizes the need for further research to explore the various applications of taro and improve on-farm processing conditions for industrial purposes.

Variation in mineral element composition of landrace taro (Colocasia esculenta) corms grown under dryland farming system in South Africa

Taro [Colocasia esculenta (L.) Schott] has the potential to address food and nutrition insecurity in sub-Saharan Africa. However, the nutrient content of taro is yet to be fully elucidated. The objective of this study was to evaluate mineral element content as a proxy for nutritional value of different taro genotypes. The study evaluated 14 taro accessions at Roodeplaat and Umbumbulu in South Africa based on their calcium (Ca), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), phosphorous (P) and zinc (Zn) content. The accessions were planted in a randomized complete block design, replicated three times under field conditions. The mineral element content varied significantly (p < 0.05) among the genotypes. Genotypes Amad7-2, Umbu8 and Amad101 exhibited high Ca (≥432 mg kg^-1), Fe (≥32 mg kg^-1) and Mg (≥229 mg kg^-1) across the locations. The first principal component (PC) accounted for 33.7% of the variation and was strongly associated with Zn (r = 0.94, p < 0.001) and P (r = 0.89, p < 0.001). The second PC explained 29.7% of the variation and was associated with Na (r = 0.83, p < 0.001), Mg (r = 0.76, p < 0.001) and K (r = 0.55, p < 0.05). Fe and Mn contributed below the 12.5% threshold to the PCs and were considered as less discriminatory among the accessions. The negative correlations among some of the mineral elements would be a challenge for selection and breeding of nutritious taro accessions. This information is essential to select superior local accessions based on their mineral element content for developing breeding populations and lines for improving nutrition quality among poor households in sub-Saharan Africa.

Aroids as underexplored tubers with potential health benefits

Colocasia esculenta (L.) Schott and Xanthosoma sagittifolium (L.) Schott are the most popular tubers among the Araceas family. Their chemical composition related to their nutritional benefits could make these rhizomes a valid option for the nutritional and technological improvement of food products. This chapter provide a clarification about the correct nomenclature of both tubers giving an insight around the principle components and their health effects. The scientific literature review has primarily highlighted several in vitro and animal studies where the consumption (leaves and whole tuber) of Colocasia esculenta (L.) Schott and Xanthosoma sagittifolium (L.) Schott was related with certain antihyperglycemic, antihypertensive, hypoglycemic and prebiotic effects. Owing to their functional properties, different component from these rhizomes, specially starch, mucilage and powders are being used by the food industry. Their ability to behave as thickener and gelling agent has allowed their incorporation in baked food, food paste and beverages. This chapter suggests the development of more research around these rhizomes since they could potentially play, with other crops, an important role in the future sustainable strategies to feed the planet.

Use of flour from cormels of Xanthosoma sagittifolium (L.) Schott and Colocasia esculenta (L.) Schott to develop pastes foods: Physico-chemical, functional and nutritional characterization

The corms of cocoyams, specifically Colocasia esculenta (L.) Schott and Xanthosoma sagittifolium (L.) Schott are usually consumed as pastes. Nevertheless, the secondary corms, also named cormels, are not fully exploited. In this study, the chemical composition and functional properties of cormels from different botanical sources were evaluated, and the digestibility of the resulting pastes investigated. Colocasia spp. flour contained significantly higher protein (10.32% vs 9.65%), ash (5.65% vs 5.05%) and oxalates (0.32% vs 0.22%) content, and exhibited lower Amylab gel strength (773 g vs 1040 g) than Xanthosoma spp. flour. In the resulting pastes, micrographs revealed that starch gelatinization depended on cocoyam variety. Indeed, the very tight and closed microstructure of pastes containing Colocasia spp. flour led them to better stability during storage with lower syneresis. Lower protein digestibility was obtained in Colocasia spp. gels (67.56% vs 70.91%), but they showed faster (higher k) in vitro starch hydrolysis (0.0140 vs 0.0050) with lower estimated glycemic index (61.29 vs 65.84) than Xanthosoma spp. gels. The present findings offer ways to develop cocoyam based foods by using cormels, enhancing the applicability of cocoyams.