Thermostability of black rice (Oryza sativa L.) nutraceuticals during a straight-dough bread-making process

Rice (Oryza sativa L.) represents an important food source worldwide. Black cultivars are particularly rich in phenolics and flavonoids (particularly in anthocyanins), which can reduce the risk of different pathologies related to oxidative stress. Cooking, however, unavoidably induces phenylpropanoid loss because of their thermosensitivity. The aim of this study was to investigate the phenylpropanoid thermostability of bread prepared using a black rice/Manitoba flour mix. Two baking times were tested, 15 min and 25 min. Black rice flour furnished 94% of phenols, 85% of flavonoids and the totality of anthocyanins to the flour mix. Baking induced a significant loss of total phenolics and anthocyanins, irrespective of the baking time. Nevertheless, 100 g of black rice-enriched bread still provided averagely 97, 50 and 16 mg of total phenols, flavonoids and anthocyanins, respectively. Therefore, use of black rice flour in bakery represents a great opportunity to enrich diet with flavonoids and mainly anthocyanins.