Application of butterfly pea flower extract in processing some Vietnamese traditional foods

Butterfly pea flower (BPF) extract was applied to the processing of traditional Vietnamese food products to bring attractiveness and safety. Different cooking techniques as steaming, boiling, frying, baking, and sterilization were used and controlled. All products were analyzed for total anthocyanin content remaining after processing conditions. The selected percentage of extract and treatment time (minutes) in different processing methods were obtained: Bloating fern-shaped cake/thin cakes (bánh bèo) (10% extract – steaming time 7 min); Rice ball sweet soup – chè ỉ) (15% extract – boiling time 6 min), fried Meat stuffed rice ball – viên thịt) (10% extract (v/w) – frying time 4 min), and bread (15% extract – baking temperature 160°C). Half-life values of anthocyanin degradation at different temperatures (through cooking methods) were observed. A case study was performed with BPF drink, this product had high quality when adding 5% BPF extract (v/v), sterilized at 125°C for 3 min with extended storage time (more than 4 months). The degradation of anthocyanin during storage was modeled according to the first-order kinetics. The half-life values were calculated as 38 and 46 weeks, respectively, at ambient (28 ± 2°C) and low temperature (6 ± 2°C) storage.