Optimizing the texture and retrogradation properties of Niangao (Rice Cake) made with naturally fermented rice flour

Abstract Niangao is prepared from polished round-grained or waxy rice flour and it is a popular and traditional steamed rice cake in China, but its preparation is different. In this study, Niangao was produced with naturally fermented rice flour and the effects of fermentation on physical properties and rheological characteristics were investigated. The results suggest that the water-holding capacity, texture, and color of the samples were significantly improved after natural fermentation, while amylose content was decreased. Additionally, fermentation had a marked effect on retarding the retrogradation of Niangao because fermented Niangao exhibited lower degree of retrogradation compared with the control. Control means Niangao which was produced by unfermented rice flour. Fermented Niangao was harder to be digested than the control was

Formation and Identification of Lignin-Carbohydrate Complexes in Pre-hydrolysis Liquors

Funding Information: This work was supported by the National Natural Science Foundation of China (nos. 21908048, 32001705, and 32071722), the China Scholarship Council (nos. 201908420037 and 201908420032), the Canada Excellence Research Chair Program (CERC-2018-00006), and the Canada Foundation for Innovation (project number 38623). Publisher Copyright: © 2023 The Authors. Published by American Chemical Society.The lignin-carbohydrate complexes (LCCs) typically present in the liquors produced in the pre-hydrolysis of biomass cause severe difficulties in downstream fractionation. To address this issue, a series of LCC samples were accessed from solutions obtained from the pre-hydrolysis of extractive-free pine wood meal (H-LCC) and compared with LCC obtained from the corresponding residues (B-LCC). Chromatographic and spectroscopic techniques revealed that 8.2% of the lignins were degraded at 160 °C, resulting from the breakage of β-O-4′ linkages during pre-hydrolysis. Meanwhile, (reactive) hemicelluloses were mainly removed from the fibers' cell walls. Some hemicelluloses in the pre-hydrolysis liquor, such as glucomannans, were associated with degraded lignin fragments via ether and ester bonds. However, the newly formed LCCs were pH-labile and underwent rapid hydrolysis. Overall, we reveal details about LCC formation and degradation during pre-hydrolysis at given temperatures, critically important in efforts to improve biomass processing and valorization.Peer reviewe