Effect of Different Starches on Edible Quality, In Vitro Starch Digestibility, and Antioxidant Property of Black Rice Noodle

Abstract

Although the nutritional value of black rice (BR) is high, the low amylose content makes undesirable qualities in black rice noodle (BRN) and leads to low levels of acceptance by consumers. In this work, mung bean starch (MBS), potato starch (PS), and corn starch (CS) are added (30% w/w based on BR) to BRN and the effects on the edibility, in vitro starch digestibility, and antioxidant properties are investigated. The results show that starches significantly reduced the cooking loss from 30.80% to 10.80% and broken rate from 44.43% to 0.00%, and increased the springiness and the extensibility properties of BRN while maintaining the low in vitro starch digestibility by characterizing the content of rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS). Starches reduce the loss of total polyphenols of BRN during cooking, improve the release rate of polyphenols in the intestinal digestion, and maintain high DPPH and ABTS radical scavenging rate. Furthermore, scanning electron microscope (SEM) reveals that starches stabilized the microstructure of BRN by forming hydrogen bonds with BR and interfering with the reassociation of starch chains (confirmed by low field nuclear magnetic resonance (LF-NMR), X-ray diffraction XRD, Fourier transform-infrared spectroscopy (FT-IR), and rapid visco analyzer (RVA)). MBS shows the most positive effect on edible quality of BRN.