Carotenoid profiling of yams: Clarity, comparisons and diversity

Elliott J Price,Ranjana Bhattacharjee,Antonio Lopez-Montes,Paul D Fraser

doi:10.1016/j.foodchem.2018.03.066

Abstract

Screening carotenoids of elite accessions of yam (Dioscorea spp.) used in the global yam breeding program has been conducted to quantitatively determine the carotenoid composition of the crop. Comparisons to previous data reporting cerotenoid levels in yam has been made, in order to deduce greater perspectives across multiple studies. Characterisation of complex species and accession -specific profiles have shown a rich base of diversity that can inform breeding strategies. Key findings include; (i) the identification of accessions rich in β-carotene which can aid provitamin A biofortification, (ii) Data disputing the commonly held belief that yellow Guinea yam (D. cayennensis) has higher β-carotene content than that of white Guinea yam (D. rotundata), and (iii) the tentative identification of C25-epoxy-apocarotenoid persicaxanthin with potential implications for tuber dormancy.

Highlights

Yams (Dioscorea spp.) are a staple starchy tuber for 60–100 million people (Mignouna, Abang, & Asiedu, 2003)
Yam is understudied when compared to other tropical root and tuber crops
Accessions covering four species of Dioscorea were grown in field conditions of the Yam Breeding Unit of the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria

Summary

Introduction

Yams (Dioscorea spp.) are a staple starchy tuber for 60–100 million people (Mignouna, Abang, & Asiedu, 2003). Favourable sensorial traits, better storage qualities and socio-economic importance have led yam to being considered as an agricultural commodity of superior economic value to alternative starchy crops (Osunde, 2008). Demand outstrips supply and it has been noted that, as income increases, consumers shift from cassava to yam (Sanginga, 2015). Despite these consumer preferences, yam is understudied when compared to other tropical root and tuber crops. Recent research on tropical crops has involved biofortification efforts, including enhancing provitamin A through increasing amounts/biosynthesis of β-carotene. Approaches have involved capturing natural diversity and targeted breeding, e.g., the HarvestPlus program (www.harvestplus.org), the CGIAR research program on roots, tubers and bananas (CGIAR-RTB) Approaches have involved capturing natural diversity and targeted breeding, e.g., the HarvestPlus program (www.harvestplus.org), the CGIAR research program on roots, tubers and bananas (CGIAR-RTB) (www.rtb.cgiar. org) and for taro; or through genetic modification such as for GoldenRice (www.goldenrice.org), BioCassava Plus (Sayre et al, 2011), Bananas (www.banana21.org) and the Generation Biogreen Program (sweet potato) (Park et al, 2015)

Methods

Results

Conclusion