Characterisation and stability of anthocyanins in purple-fleshed sweet potato P40

Citation: Xu, J., Su, X., Lim, S., Griffin, J., Carey, E., Katz, B., … Wang, W. (2015). Characterisation and stability of anthocyanins in purple-fleshed sweet potato P40. ISPMF 2015: International Symposium on Phytochemicals in Medicine and Food (Shanghai, China, June 26th –29th, 2015), 186, 90–96. https://doi.org/10.1016/j.foodchem.2014.08.123Purple-fleshed sweet potato P40 has been shown to prevent colorectal cancer in a murine model. This study is to identify anthocyanins by using HPLC/MS–MS and assess the stability during various cooking conditions. P40 possesses a high content of anthocyanins up to 14 mg/g dry matter. Total 12 acylated anthocyanins are identified. Top three anthocyanins, e.g., cyanidin 3-caffeoyl-p-hydroxybenzoyl sophoroside-5-glucoside, peonidin 3-caffeoyl sophoroside-5-glucoside, and cyanidin 3-(6″-caffeoyl-6″-feruloylsophoroside)-5-glucoside, account for half of the anthocyanin contents. Over 80% of anthocyanins measured by acid hydrolysis were cyanidin derivatives, indicating P40 is unique when compared with other purple-fleshed sweet potatoes that usually contain more peonidin than cyanidin. Steaming, pressure cooking, microwaving, and frying but not baking significantly reduced 8–16% of total anthocyanin contents. Mono-acylated anthocyanins showed a higher resistance against heat than di- and non-acylated. Among of which, cyanidin 3-p-hydroxybenzoylsophoroside-5-glucoside exhibited the best thermal stability. The stable acylated and cyanidin-predominated anthocyanins in P40 may provide extra benefits for cancer prevention