Open AccessThe effect of pH on the chemical and structural interactions between apple polyphenol and starch derived from rice and maize
Author(s) -
Chou Shurui,
Li Bin,
Tan Hui,
Zhang Weijia,
Zang Zhihuan,
Cui Huijun,
Wang Hanchen,
Zhang Shuyi,
Meng Xianjun
Publication year - 2020
Publication title -
food science and nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.614
H-Index - 27
ISSN - 2048-7177
DOI - 10.1002/fsn3.1800
Subject(s) - starch , crystallinity , polyphenol , chemistry , food science , fourier transform infrared spectroscopy , enthalpy , nuclear chemistry , biochemistry , crystallography , chemical engineering , antioxidant , physics , quantum mechanics , engineering
To date, how pH affects starch–polyphenol mixtures has not been thoroughly investigated. This study explored the impact of combining apple polyphenol (AP) with both normal rice starch (NRS) and normal maize starch (NMS) across a range of pH conditions. NRS–AP mixture particle sizes across a pH range of 3–8 varied from 169.9 ± 5.4 to 187.5 ± 6.9 μm, while for NMS–AP particles, these sizes ranged from 161.8 ± 8.0 to 176.0 ± 4.9 μm, indicating that the aggregation of starch–AP was inhibited under low pH condition. The melting enthalpy (△H) values of the NRS–AP mixture across a pH range of 3–8 were 8.50 ± 0.06–9.56 ± 0.12 J/g, while the corresponding value for the NMS–AP mixture was 5.77 ± 0.05–6.21 ± 0.08 J/g. FTIR analyses revealed that the degree of order of these starch–AP mixtures significantly decreased under low pH conditions. XRD analysis further revealed that both NRS–AP and NMS–AP mixtures exhibited V‐type structures, and relative crystallinity levels decreased significantly under low pH conditions. Together, these results indicate that low pH values inhibit the recrystallization of NRS–AP and NMS–AP mixtures. Overall, these findings provide additional evidence regarding the interactions between AP and specific starches under a range of pH conditions.