Chemistry Department, De La Salle University, 2401 Taft, Avenue, Manila 0922, Philippines; Grain Quality and Nutrition Center, Strategic Innovation Platform, International Rice Research Institute, Los Baños, Laguna, Philippines; Chemistry Department, University of Santo Tomas, Espana, Sampaloc, Manila 1008, Philippines. Chemistry Department, De La Salle University, 2401 Taft, Avenue, Manila 0922, Philippines; Grain Quality and Nutrition Center, Strategic Innovation Platform, International Rice Research Institute, Los Baños, Laguna, Philippines. Grain Quality and Nutrition Center, Strategic Innovation Platform, International Rice Research Institute, Los Baños, Laguna, Philippines. Electronic address: n.sreenivasulu@irri.org. Chemistry Department, De La Salle University, 2401 Taft, Avenue, Manila 0922, Philippines; Organic Materials and Interfaces Unit, CENSER, De La Salle University, 2401, Taft Avenue, Manila 0922, Philippines. Electronic address: drexel.camacho@dlsu.edu.ph.