Effects of different concentrations of NaOH on the structure and in vitro digestion of cellulose from sesame kernel
Run‐Yang Zhang, Chen Liu, Xue‐De Wang, Hua‐Min Liu, Wen‐Xue Zhu
Abstract
Sesame kernel are a common and popular raw-food materials throughout the world. However, the sesame cellulose-rich residue is often discarded as waste after the industrial production process of oil and protein. In this work, four kinds of cellulose samples were extracted from sesame kernel using different strengths of an alkaline solution (0.5, 1.0, 2.0, 3.0 mol/L NaOH) under laboratory conditions. After in vitro simulated digestion of these samples, the relative amount of glucose increased by 1.09–3.17%, while the contents of xylose, arabinose, galactose and mannose decreased to varying degrees. Many tiny pores on the surface of the digested samples were observed by scanning electron microscope. Their thermal stabilities increased because of the loss of non-cellulose components during digestion. Fourier infrared spectrograms and X-ray diffraction spectra also showed that the structure of these celluloses had changed after digestion. The amounts of reducing sugars and polyphenols released at three digestion stages (oral, gastric, intestinal) were also measured. Overall, the celluloses obtained by 2 and 3 mol/L NaOH (AR-2, AR-3) were highly resistant to digestion compared to those obtained by 0.5 and 1 mol/L NaOH (AR-0.5, AR-1). These analyses provide basic information for the application of sesame cellulose in the food industry.