Color and stability of anthocyanins in strawberry nectars containing various co-pigment sources and sweeteners.

Effects of various co-pigment sources [gallic acid (GA) and the extracts of rose leaf (RLE), cherry stem (CSE), pomegranate rind (PRE) and sour cherry stem (SCSE)] on anthocyanins and colour in strawberry nectars (SNs), sweetened with sucrose (SNS), maltose syrup (SNM) and honey (SNH), were investigated during storage at 20 °C. Honey elicited the highest stabilities of anthocyanins, hyperchromic and bathochromic effects in SNs containing all co-pigment sources, except for PRE. PRE co-pigments were composed of mainly tannins which could interact with SNs proteins and honey proline. As a result of these interactions, PRE co-pigments could not show significant contribution to protection of SN anthocyanins and colour. Among co-pigment sources, SCSE caused the highest stabilities of anthocyanins, hyperchromic effect and colour density, regardless of sweetener used. Interactions between SCSE phenolic acids, and pelargonidin-3-glucoside and pelargonidin-3-rutinoside resulted in the most stable co-pigmentation effect. Thus, SCSE should be preferred in beverages containing pelargonidin-based anthocyanins.