Effects of Polishing and Cooking on the Phytochemical Properties and Antioxidant Activities of Selected Philippine Rice Cultivars [RESEARCH NOTE]

Authors

Rodel M. Bulatao, Rice Chemistry and Food Science Division, Philippine Rice Research Institute, Maligaya, Science City of Muñoz, Nueva Ecija, 3119 PhilippinesFollow
Charleo S. Zapanta, Department of Chemistry, College of Science, Central Luzon State University, Science City of Muñoz, Nueva Ecija, 3120 Philippines
Maricar B. Castillo, Rice Chemistry and Food Science Division, Philippine Rice Research Institute, Maligaya, Science City of Muñoz, Nueva Ecija, 3119 Philippines
Reniel P. Tubera, Rice Chemistry and Food Science Division, Philippine Rice Research Institute, Maligaya, Science City of Muñoz, Nueva Ecija, 3119 Philippines
Joel R. Salazar, Department of Chemistry, College of Science, Central Luzon State University, Science City of Muñoz, Nueva Ecija, 3120 Philippines

Publication Date

9-1-2023

Abstract

This paper evaluated the effects of different polishing times and regular cooking on the phytochemical properties and antioxidant activities of black rice Brillante, red rice Minaangan, and white rice NSIC Rc 160. Rice samples were polished for 0, 15, 30, and 45 s, and were cooked using their optimum cooking water ratio. The samples were then characterized for their phytochemical properties [total anthocyanin content (TAC), total phenolic content (TPC), and total flavonoid content (TFC)] and antioxidant activities [DPPH-radical scavenging activity (DPPH-RSA) and ferric reducing antioxidant power (FRAP)]. Pearson’s correlation analysis (PCA) was employed to determine the strength of the linear relationship between the polishing times and different parameters tested. Results showed that the pigmented rice samples had significantly higher phytochemical properties and antioxidant activities than the white rice sample. Polishing of rice samples considerably reduced their TAC (4.8% to 52.7%), TPC (13.0% to 65.2%), TFC (11.2% to 61.5%), DPPH-RSA (35.0% to 79.9%), and FRAP (11.8% to 68.5%). Cooking also decreased their TAC (24.1% to 92.6%), TPC (14.3% to 78.0%), TFC (14.4% to 74.2%), DPPH-RSA (38.9% to 84.6%), and FRAP (37.0% to 92.8%). Moreover, PCA showed that the polishing time had a strong to very strong negative correlation with phytochemical properties (-0.8809 to -0.9846) and antioxidant activities (-0.8106 to -0.9763). This study concluded that the polishing and cooking significantly affected the phytochemical content and antioxidant activities of white and pigmented rice cultivars. The information generated can be used as a basis for selecting suitable processes to better preserve the antioxidants of pigmented rice.

Recommended Citation

Bulatao, Rodel M.; Zapanta, Charleo S.; Castillo, Maricar B.; Tubera, Reniel P.; and Salazar, Joel R. (2023) "Effects of Polishing and Cooking on the Phytochemical Properties and Antioxidant Activities of Selected Philippine Rice Cultivars [RESEARCH NOTE]," The Philippine Agricultural Scientist: Vol. 106: No. 3, Article 8.
Available at: https://www.ukdr.uplb.edu.ph/pas/vol106/iss3/8