There is more to rice than starch: exploring the phytonutrient content of Philippine pigmented rice varieties

There is an increasing incidence of lifestyle-related chronic diseases such as cardiovascular diseases and cancer. This has led to the exploration of food components with health-enhancing effects. The antioxidant properties of phytonutrients, including anthocyanins and other polyphenols, are associated with lowering the risks for these diseases, which are caused by cell-damaging free radicals. Rice is primarily consumed for its carbohydrates as source of energy, but phytonutrients in various kinds of rice lie untapped. This study was conducted to investigate the potential of local pigmented rice varieties as alternative sources of phytonutrients. Different milling fractions of four pigmented rice varieties (Dinorado, Ballatinao, Calatrava, and La Castellana) and a non-pigmented variety (IR64) were assayed for anthocyanin concentration, phenolic content, and total antioxidant activity using the modified pH differential method, Folin-Ciocalteau procedure, and DPPH radical scavenging technique, respectively. Anthocyanins were found to be concentrated in the bran, with Ballatinao having the greatest amount (469.67 mg/kg). However, Calatrava contained the highest concentration of anthocyanins in the endosperm. Similar trends were observed for the phenolic content of the samples. Phenolics (14.71 mg gAE/g sample) were highest in Ballatinao bran, while polished Calatrava had the highest level (1.55 mg GAE/g). Whole grain Ballatinao, with high levels of anthocyanins and the highest phenolic content among the samples, exhibited antioxidant activity which is comparable with butylated hydroxyanisole, a commercially available antioxidant. These results suggest that pigmented rice may serve as excellent sources of health promoting and disease-preventing components and can be explored for utilization in the food and pharmaceutical industries.