*Article* **Effects of Three Types of Polymeric Proanthocyanidins on Physicochemical and In Vitro Digestive Properties of Potato Starch**

**Jiahui Xu 1, Taotao Dai 2, Jun Chen 1, Xuemei He 2, Xixiang Shuai 1, Chengmei Liu <sup>1</sup> and Ti Li 1,\***

<sup>1</sup> State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China; xl19961019@126.com (J.X.); chen-jun1986@hotmail.com (J.C.); shuaixixiang1989@163.com (X.S.); liuchengmei@aliyun.com (C.L.)

<sup>2</sup> Agro-Products Processing Science and Technology Research Institute, Guangxi Academy of Agricultural Sciences, Nanning 530007, China; daitaotao@gxaas.net (T.D.); xuemeihe1981@126.com (X.H.)

**\*** Correspondence: liti@ncu.edu.cn

**Abstract:** The effects of three types of polymeric proanthocyanidins (PPC) with different degrees of polymerization (DP), namely PPC1 (DP = 6.39 ± 0.13), PPC2 (DP = 8.21 ± 0.76), and PPC3 (DP = 9.92 ± 0.21), on the physicochemical characteristics and in vitro starch digestibility of potato starch were studied. PPC addition (5%, *w/w*) increased the gelatinization temperature and decreased some viscosity indices of potato starch, including the peak, trough, breakdown, and setback viscosities. Starch-PPC pastes showed reduced thixotropy and improved stability and gelling properties compared to starch paste. The three types of proanthocyanidins all showed evident inhibitory effects on the digestion and retrogradation of potato starch, including short-term and long-term retrogradation. Among the three, PPC with a lower DP had stronger effects on the starch short-term retrogradation and gelling performance, whereas larger PPC molecules exhibited a greater impact on starch recrystallization and digestive characteristics. The research consequences were conducive to explore the application of functional PPC in starch-based food processing.

**Keywords:** polymeric proanthocyanidin; degree of polymerization; starch; pasting; retrogradation; digestibility
