Change in total proteins, storage proteins, sugars, and polyphenols in cocoyam ( <i>Xanthosoma sagittifolium</i> L. Schott) tubers from white and red cultivars during storage at room temperature

Abstract Background: Cocoyam ( Xanthosoma sagittifolium L. Schott) tubers represent one of the most essential sources of nutritional carbohydrates in many developing countries. However, few studies and less funding have been devoted to increasing its value chain. This research aims to investigate the changes in some biochemical compounds in two cocoyam cultivars with differing agromorphological traits. Methods: Yield parameters, storage proteins, sugars, and total phenolic compounds were determined during post-harvest storage of tubers at room temperature. Results: The analysis of physical parameters at harvest revealed that the weight, length, and diameter of the tubers were significantly higher for the white cultivar compared to the red cultivar. The analysis of tubers during storage revealed an increase in total proteins and storage proteins (albumin, globulin, prolamin, and glutelin) in both cultivars. Albumin was the most representative storage protein in the white cultivar, while in the red cultivar, the amounts of albumin, globulin, and glutelin were not significantly different at harvest. Results from starch and soluble sugar analysis indicate a decrease in starch content and a significant increase in soluble sugars during storage in tubers of both cultivars. The starch content varied from 270.3 ± 5.4 mg/g to 502.2 ± 3.8 mg/g with a mean of 382.74 ± 6.33 mg/g for the white cultivar and from 292.98 ± 0.01 mg/g to 789.19 ± 0.79 mg/g with a mean of 585.55 ± 5.67 mg/g for the red cultivar. Mean soluble sugar content was 12.87 ± 0.34 mg/g and ranged from 5.65 ± 0.03 to 24.30 ± 1.22 mg/g in the white cultivar, and was 8.90 ± 0.19 mg/g and ranged from 6.22 ± 0.22 to 14.95 ± 0.03 mg/g in the red cultivar. Additionally, the red cocoyam cultivar exhibited a higher content of total phenolic compounds compared to the white cultivar. Conclusion: This study presents valuable data on white and red cocoyam cultivars, highlighting their potential for improved use in industrial applications.