This study aimed to evaluate a two-stage sequential approach based on subcritical water technology and the use of citric and malic acids to first extract soluble polysaccharides from pea hull fiber and then hydrolyze them into oligosaccharides. Subcritical water extraction with aqueous citric acid (120 °C/50 bar/30 min) yielded 11.8% pea soluble polysaccharides comprised of pectic fragments (17.4% galacturonic acid) with an esterification degree of 50.9%. Pectic fragments were estimated as rhamnogalacturonan-I, xylogalacturonan and xyloglucan. The HPSEC/RID and HILIC-ELSD analyses showed that subcritical water hydrolysis of pectic fragments into oligosaccharides was favored by aqueous citric and malic acids (0.2%) at 100 bar between 125 °C and 155 °C. The yields of released gluco-oligosaccharides (2–6 DP) were 6.1% and 20.4% at 125 °C and 135 °C/100 bar/120 min, respectively. The main hydrolysis mechanism exhibited a stepwise pattern, where rhamnogalacturonan-I side chains were cleaved first followed by their breakdown into reduced molecular weight compounds and oligosaccharides.

本研究旨在评估基于亚临界水技术和使用柠檬酸和苹果酸首先从豌豆壳纤维中提取可溶性多糖，然后将其水解成低聚糖的两阶段顺序方法。用柠檬酸水溶液 (120 °C/50 bar/30 分钟) 进行亚临界水萃取，产生 11.8% 的豌豆可溶性多糖，由酯化度为 50.9% 的果胶片段（17.4% 半乳糖醛酸）组成。果胶片段被估计为鼠李糖半乳糖醛酸-I、木糖半乳糖醛酸聚糖和木葡聚糖。HPSEC/RID 和 HILIC-ELSD 分析表明，在 125 °C 和 155 °C 之间的 100 bar 压力下，柠檬酸和苹果酸水溶液 (0.2%) 有利于果胶片段亚临界水水解成寡糖。释放的低聚糖 (2-6 DP) 的产率为 6.1% 和 20。分别在 125 °C 和 135 °C/100 bar/120 分钟时为 4%。主要的水解机制表现出逐步模式，其中鼠李糖半乳糖醛酸聚糖-I 侧链首先被裂解，然后分解成降低分子量的化合物和寡糖。