Structural and Digestive Properties of High-amylose Maize Starch
Dosage-regulated by Large-leaf Yellow Tea Aqueous Extract
LIU Yang1, LUO Deng-huan1, ZHOU Li-wei1,2, CHU Ling-jun1, CHEN Qi1,2, XU Na1,2*
(1. College of Food and Nutrition, Anhui Agricultural University, Key Laboratory of Jianghuai Agricultural Product Intensive Processing and Resource Utilization, Ministry of Agriculture and Rural Affairs, Hefei, Anhui 230036, China; 2. State Key Laboratory of Tea Plant Germplasm Innovation and
Resource Utilization, Anhui Agricultural University, Hefei, Anhui 230036, China)
Abstract: To promote the high-value utilization of summer-autumn large-leaf yellow tea resources, this study investigated the dose-dependent effects of large-leaf yellow tea aqueous extract (YTWE) on the multi-scale structure and digestive properties of high-amylose maize starch (HAMS). YTWE was added at 0%, 5%, 10% and 15% (based on starch dry weight) and co-gelatinized with HAMS at 120°C to prepare tea-starch complexes (TSC). The thermodynamic properties, water status, crystalline structure, short-range order parameter, microstructure and digestibility of TSC were analyzed using DSC, LF-NMR, ¹H-NMR, XRD, FT-IR, SEM and the Englyst in vitro digestion model. The results indicated that with the increase in YTWE dosage, the gelatinization onset temperature (T0) increased , while the gelatinization enthalpy (ΔH) decreased from 5.35 J/g to 2.90 J/g. The free water in the starch gel was gradually transformed into multi-layer water, and the proton resonance peak shifted to a lower magnetic field. Both relative crystallinity and the 1 047/1 022 cm–1 ratio (short-range order) increased in a concentration-dependent manner. In vitro digestion revealed a bidirectional dose-dependent effect of YTWE on starch digestibility. Compared with the control (GHACS), 5% YTWE increased rapidly digestible starch (RDS) from 59.74% to 70.26%, decreased resistant starch (RS) from 25.01% to 10.39%, and raised the final hydrolysis degree (C∞) from 75.05% to 86.79%. In contrast, 15% YTWE reduced the RDS content to 43.51%, increased the RS content to 43.87%, and decreased C∞ to 60.26%. YTWE interacts with HAMS through non-covalent interactions such as hydrogen bonding. At low concentration (5%), YTWE mainly disrupts the ordered structure of starch and exposes enzyme cleavage sites, thereby promoting digestion. At high concentration (15%), it induces the formation of a denser and more ordered gel network, increases crystallinity, and restricts water mobility, thus significantly inhibiting digestion. This study revealed the non-linear dose-dependent effect of crude yellow tea extract on starch digestibility and its multi-scale structural basis, providing a theoretical reference for regulating starch digestibility and utilizing large-leaf yellow tea by-products.
Key words: high-amylose maize starch; large-leaf yellow tea; digestive properties; resistant starch; dose- dependent; multi-scale structure
Chinese Library Classification Number: TS231.2
Documentary Identification Code: A Article ID: 1007-7561(2026)05-0066-10
Published time on CNKI: 2026-08-27 14:15:51
Published address on CNKI: https://link.cnki.net/urlid/11.3863.TS.20260827.0949.008
