Calibration development for nutritional evaluation of Yam (Dioscorea sp.) using Near-Infrared Reflectance Spectrophotometry (NIRS)

Abstract

The aim of yam breeders is to produce many hybrids, which can form the basis of selecting quality nutritional traits and other characteristics using certain agronomic criteria. Chemical methods are employed to determine the main constituents of yam, which are time-consuming, expensive, and involve sample destruction. However, the constraints of lengthy analysis time and the cost needed to analyze thousands of these genotypes are major constraints to yam breeding in Nigeria. This study was undertaken to develop and validate calibration equations on the Near-Infrared Reflectance Spectrophotometer (NIRS) for determining chemical compositions of selected yam genotypes. Equations developed for moisture, ash, protein, crude fiber, and tannin showed high coefficients of determination (R 2) for the calibration curve (0.87, 0.84, 0.83, 0.80, and 0.89, respectively) and high to medium coefficients of determination in cross-validation (0.80, 0.68, 0.69, 0.68, and 0.50). The standard errors of calibration (SEC) and the standard errors in cross-validation (SECV) were low for most constituents. A total of 360 ascensions of yam flour were predicted for selected traits to test the equations, and the results were comparable with data from conventional methods. Results of this study have shown that NIRS could be a very useful tool to help yam breeders screen large sample sets using limited resources with very short ABOUT THE AUTHORS Our research is focused on characterization of food crops and their products for nutritional and functional traits. Specifically, we are working on characterization of improved and released varieties of maize, cowpea, soybean, cassava and plantain and banana. We are into novel products from these crops with aim to use them to improve malnutrition mostly among the vulnerable groups of developing countries. We work closely with crop breeders in IITA to develop and applied improved methods for analysis of the bred crops for various nutritional and antinutri-tional compositions. Thus, breeders could take prompt and reliable decisions to achieve their various breeding objectives for crop improvement. PUBLIC INTEREST STATEMENT Recently, researchers have been working on increasing the nutrient in the crops and improving the quality characteristics of the crops to meet consumer preferences. To achieve this, the researchers need a fast and cost-effective method of analysis. This study was aimed to apply Near-Infrared Reflectance Spectrophotometer (NIRS) for figuring out chemical constituents of different types of yam samples from different locations. NIRS calibration equations were developed, tested and used to analyze the yam flour samples and compared the results with the literature values. The developed equations could be used for moisture, ash, protein and starch contents determinations of yam flour samples. Thus, NIIRS could be considered as a substitute to the time consuming and labor intensive wet chemical methods of analysis which will in turn minimize exposure to toxic chemicals, provide high turnaround time and minimize cost. Alamu et al., Cogent Chemistry (2019), 5: 1565623 https://doi. Attribution (CC-BY) 4.0 license. time. This will enhance breeders' rapid selection of genotypes at screening stage where many breeding lines are to be evaluated within the shortest time possible.