Chai Yuan, Wang Ruibin, Zhang Bo, Tang Yonglu, Li Chaosu, Guo Boli, Li Ming
College of Food Science and Engineering, Shanxi Agricultural University, Jinzhong 030801, China.
Institute of Food Science and Technology, Chinese Academy of Agriculture Sciences/Comprehensive Utilization Laboratory of Cereal and Oil Processing, Ministry of Agriculture and Rural, Beijing 100193, China.
Foods. 2025 May 21;14(10):1829. doi: 10.3390/foods14101829.
This study elucidated the mechanistic interplay between the extrusion parameters (temperature and screw speed), starch molecular architecture (chain-length distribution), and key physicochemical properties of wheat flour extrudates. Four wheat flours with varied amylose contents were extruded, where the average hydrodynamic radius (Rh-) was reduced by 75.5% in normal wheat (e.g., CM55), while waxy wheat (WW) exhibited higher Rh-. Crispness correlated negatively with long amylopectin branches (36 < X ≤ 100), with WW displaying superior crispness (12.22 N/mm). Short amylopectin chains (X 6-36) increased under thermomechanical stress, enhancing the expansion index (SEI), whereas long chains (X > 100) restricted expansion. Temperature may modulate color difference (Δ) via Maillard reactions, while higher specific mechanical energy (SME) intensified browning. Higher temperatures (>170 °C), rather than SME, caused significant changes in the proportion of short branches and long branches, with SME exhibiting a negative correlation with Rh-, indicative of substantial molecular degradation. The starch chain-length distribution, rather than amylose content alone, dictates extrudate functionality.
本研究阐明了挤压参数（温度和螺杆转速）、淀粉分子结构（链长分布）与小麦粉挤压物关键物理化学性质之间的作用机制。对四种直链淀粉含量不同的小麦粉进行挤压，普通小麦（如CM55）的平均流体力学半径（Rh-）降低了75.5%，而糯小麦（WW）的Rh-更高。脆度与支链淀粉长链（36 < X ≤ 100）呈负相关，糯小麦表现出更高的脆度（12.22 N/mm）。在热机械应力下，支链淀粉短链（X 6 - 36）增加，提高了膨胀指数（SEI），而长链（X > 100）则限制膨胀。温度可能通过美拉德反应调节色差（Δ），而较高的比机械能（SME）会加剧褐变。较高温度（>170°C）而非SME导致短链和长链比例发生显著变化，SME与Rh-呈负相关，表明存在大量分子降解。决定挤压物功能的是淀粉链长分布，而非单独的直链淀粉含量。
