Colour properties, stability, and free radical scavenging activity of jambolan (Syzygium cumini) fruit anthocyanins in a beverage model system: Natural and copigmented anthocyanins

The colour and stability properties of jambolan anthocyanins, both natural and copigmented forms, were investigated in beverage model as well as their radical scavenging ability. Natural anthocyanins of jambolan revealed low colour intensity due to glycosylation structure of the anthocyanins as diglucoside. The intermolecular copigmentation of anthocyanins with sinapic acid, caffeic acid, ferulic acid, and rosemary polyphenolic extract could enhance the colour intensity, which was observed through spectrometric parameters, such as hyperchromic effect (ΔAvis-max) and bathochromic shift (Δλvis-max). In addition of sinapic acid, caffeic acid, and rosemary polyphenolics also increased the stability of the anthocyanin colour during exposure to white fluorescent light and storage at refrigeration and room temperatures, whereas on high thermal treatments, this phenomenon was not observed. Furthermore, beverage model coloured with natural or copigmented anthocyanins revealed DPPH radical-scavenging activity. The AEAC values indicated that the beverage models with copigmented anthocyanins had higher scavenging activity than the beverage with natural anthocyanins.