Characterization of Italian rice varieties and their by-products

Rice (Oryza sativa L.) is one of the world’s most important cereal crops providing a staple food source for more than 50% of the world’s population. The extent of rice cultivation in Italy is of significant importance: with 1.3 million tons a year of finished product, Italy is not only Europe’s leading producer, but one of the major non-Asian producers, after Brazil and USA (1). Pigmented rice is widely known as enriched rice for taste and health improvements; primarily produced in Southeastern Asia, recently various pigmented rice cultivar have been developed and cultivated in Italy. Rice bran, a by-product of the rice milling industry, contributes about 10% to the weight of the grain. Because it contains high amounts of structurally different bioactive compounds, bran from pigmented rice varieties has the potential to serve as a functional food that can promote human health (2). The main scope of this work was to characterize some both pigmented and white Italian varieties of rice grown in Piedmont (black varieties: Venere, Artemide, Nerone and Otello; red varieties: Ermes, Russ and Rosso Italiano; white varieties: Carnise, Carnise precoce and Selenio (this last one only partially refined)). Different by-products from rice milling were also investigated, husks from shelling process and bran from the pearling (namely “pula” and “farinaccio” from the first and the second part of the process, respectively). Rice samples were characterized for the proximate composition, the antioxidant activity (DPPH radical scavenging) and the phenolic composition (phenolic acids, flavonoids and anthocyanins). The higher antioxidant activity and phenolic content were observed for by-products obtained from the pearling process, particularly in the case of pigmented rice (black and red bran), while husks (from white rice) showed the highest fiber content (about 74%). Anthocyanins were determined only in black samples, having evidenced the prevalence of cyanidin-3-glucoside in all the varieties analyzed, while total condensed tannins were prevalent in red bran and Rosso Italiano variety (about 30 and 14 mg/g, respectively).