Zong Xinyan, Lei Ningyu, Yin Junyi, He Weiwei, Nie Shaoping, Xie Mingyong
State Key Laboratory of Food Science and Resources, China-Canada Joint Laboratory of Food Science and Technology (Nanchang), Key Laboratory of Bioactive Polysaccharides of Jiangxi Province, Nanchang University, 235 Nanjing East Road, Nanchang 330047, China.
Foods. 2024 Apr 18;13(8):1241. doi: 10.3390/foods13081241.
Acid hydrolysis serves as the primary method for determining the monosaccharide composition of polysaccharides. However, inappropriate acid hydrolysis conditions may catalyze the breakdown of monosaccharides such as fructans (Fru), generating non-sugar by-products that affect the accuracy of monosaccharide composition analysis. In this study, we determined the monosaccharide recovery rate and non-sugar by-product formation of inulin-type fructan (ITF) and Fru under varied acid hydrolysis conditions using HPAEC-PAD and UPLC-Triple-TOF/MS, respectively. The results revealed significant variations in the recovery rate of Fru within ITF under different hydrolysis conditions, while glucose remained relatively stable. Optimal hydrolysis conditions for achieving a relatively high monosaccharide recovery rate for ITF entailed 80 °C, 2 h, and 1 M sulfuric acid. Furthermore, we validated the stability of Fru during acid hydrolysis. The results indicated that Fru experienced significant degradation with an increasing temperature and acid concentration, with a pronounced decrease observed when the temperature exceeds 100 °C or the HSO concentration surpasses 2 M. Finally, three common by-products associated with Fru degradation, namely 5-hydroxymethyl-2-furaldehyde, 5-methyl-2-furaldehyde, and furfural, were identified in both Fru and ITF hydrolysis processes. These findings revealed that the degradation of Fru under acidic conditions was a vital factor leading to inaccuracies in determining the Fru content during ITF monosaccharide analysis.
酸水解是测定多糖单糖组成的主要方法。然而，不合适的酸水解条件可能会催化诸如果聚糖（Fru）等单糖的分解，产生影响单糖组成分析准确性的非糖副产物。在本研究中，我们分别使用高效阴离子交换色谱-脉冲安培检测法（HPAEC-PAD）和超高效液相色谱-三重四极杆飞行时间质谱联用仪（UPLC-Triple-TOF/MS），测定了菊粉型果聚糖（ITF）和Fru在不同酸水解条件下的单糖回收率和非糖副产物的形成情况。结果显示，不同水解条件下ITF中Fru的回收率存在显著差异，而葡萄糖相对稳定。实现ITF相对较高单糖回收率的最佳水解条件为80℃、2小时和1M硫酸。此外，我们验证了Fru在酸水解过程中的稳定性。结果表明，Fru随着温度和酸浓度的升高而显著降解，当温度超过100℃或硫酸浓度超过2M时，降解明显加剧。最后，在Fru和ITF的水解过程中均鉴定出与Fru降解相关的三种常见副产物，即5-羟甲基-2-糠醛、5-甲基-2-糠醛和糠醛。这些发现表明，酸性条件下Fru的降解是导致ITF单糖分析中Fru含量测定不准确的一个重要因素。
