Optimizing the production of green food color from mulberry leaves at different harvest times

Purpose: The white mulberry tree (Morusalba) having a low water requirement, is native to Iran. Mulberry leaf extract is a rich chlorophyll source, and natural source of antioxidants and coloring pigments. White mulberry leaf extract was studied in terms of color production ability and antioxidant properties. Research method: The extracts of mulberry leaves were extracted by pure solvents of methanol, acetone, ethanol and ۹۶% and ۸۰% ethanol. Color extraction was investigated at beginning, middle and end of the production season. Antioxidant capacity, phenolic compounds, ferric reducing power and color stability were evaluated. Findings: ۸۰% ethanol had a higher extraction rate and was cost-effective. In April and May, more total chlorophyll and carotenoid were extracted than in June. To determine the optimized antioxidant capacity, ۱۰۰% ethanol solvent, sample to solvent ratio of ۱ to ۱۰, and microwave power of ۵۰۰-watt were used. The leaves phenolic compounds extracted were highest in April (۲۴.۰۱ μg/ml) and lowest in June (۱۹.۱۳ μg/ml). The ferric reducing power was higher in the first samples of the season. Color stability decreased with pH from ۶ to ۳ and temperature increasing from laboratory temperature to ۹۰°C and receiving light. Research limitations: The extracted color was not investigated in food products. Originality/Value: Chlorophyll, carotenoids, phenolic compounds and ferric reducing power were higher in the leaves at the beginning of the season. Color extraction from leaves harvested in April with ۸۰% ethanol solvent had a higher value while maintaining pH and storage at room temperature in the dark.

Keywords:

Antioxidant , chlorophyll , Carotenoids , Food color , White berry