Abstract
Anthocyanins from flowers of the butterfly pea (Clitoria ternatea L.) are promising edible blue food colorants. Food processing often faces extreme pHs and temperatures, which greatly affects the color and nutritional values of anthocyanins. This study explored the color, spectra, storage stability, and antioxidant properties of C. ternatea anthocyanin extract (CTAE) at different pHs. The color and absorption spectra of CTAEs at a pH of 0.5–13 were shown, with their underlying structures analyzed. Then, the storage stability of CTAEs were explored under a combination of pHs and temperatures. The stability of CTAE declines with the increase in temperature, and it can be stored stably for months at 4 °C. CTAEs also bear much resistance to acidic and alkaline conditions but exhibit higher thermal stability at pH 7 (blue) than at pH 0.5 (magenta) or pH 10 (blue-green), which is a great advantage in food making. Antioxidant abilities for flower extracts from the butterfly pea were high at pH 4–7, as assessed by DPPH free radical scavenging assays, and decreased sharply when the pH value exceeded 7. The above results provide a theoretical basis for the application of butterfly pea flowers and imply their great prospect in the food industry.
Highlights
Due to the health concerns associated with synthetic pigments, the food industry has begun to invest heavily in natural food colorants [1,2]
It is a little surprising that C. ternatea anthocyanin extract (CTAE) were most stable under pH 4–8, when usual anthocyanins from other plants will continuously undergo irreversible formation of yellow Ct chalcone by the multistate equilibrium [2]
CTAE render the color of blue-green within a wide range of pH 4–10
Summary
Due to the health concerns associated with synthetic pigments, the food industry has begun to invest heavily in natural food colorants [1,2]. Common plant pigments, including anthocyanins, betalains, and carotenoids, possess a red hue (from yellow to purple) and have been recommended for use as healthy natural food colorants [3,4]. Anthocyanins are a group of bio-active water-soluble flavonoids widely distributed in the plant kingdom that can render plant tissues with hues of pink, red, purple, and blue [3,7]. They are beneficial to human health, possessing antioxidant and antiinflammatory properties, as well as the ability to prevent tumors, diabetes, and many other cardiovascular diseases [4,6,8,9]. Due to the unstable link between O1 and C2 at the C ring, anthocyanins in nature are extremely unstable and susceptible to degradation by external factors such as temperature, pH, light, oxygen, 4.0/)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
