Hongming Gu, Xian Qu, Xiaotong Sheng, Xuran Wang, Yuhan Cai, Jie Geng, Liangnan Cui, Kevin H Mayo, Yifa Zhou, Hairong Cheng, Guihua Tai
Sunflower pectin is widely used as a food additive due to its gelling and stabilizing properties. However, its bioactive potential remains poorly understood. Here, we explored its effect on defecation. Using a diphenoxylate-induced constipation mouse model, we found that native sunflower pectins did not significantly promote defecation. Subsequently, we investigated whether they could be activated via biotransformation. For this, we enzymatically hydrolyzed the pectin and produced a number of fragments that covered a wide range of molecular weights (0.5 to 30 kDa) in two esterification states (0% and 10% methyl esterification). Interestingly, all fragments exhibited defecation-promoting effects. Moreover, the effect progressively increased as the molecular weight decreased, a trend that was observed with both esterified and non-esterified fragments. Comparative studies identified E3 as the most effective fraction. E3 also displayed a prebiotic effect in the gut of model mice. Structural analysis indicated that E3 comprises oligogalacturonides with degrees of polymerization from one to six, mainly DP3 and DP4. Overall, our study reveals an inverse correlation of molecular weight with defecation-promoting activities, and offers a simple and scalable approach to convert ineffective pectin into effective oligogalacturonides that have the potential to become functional food ingredients.