The stability and application of banana bract anthocyanins in Dairy Yogurt

Abstract

Banana bracts are widely unexploited sources of anthocyanins, a flavonoid group of phytochemical which can widely be used in the food industry because of their attractive colors and numerous beneficial health effects. The aim of the current study was to develop an acceptable anthocyanin based natural pigment to provide color and enhance the anti-oxidant capacity in dairy yoghurt from the largely available culinary banana bracts. Five acidified ethanol concentrations (50%,60%,65%,70% and 80%) were used to study the optimum conditions for extraction of anthocyanins from banana bracts. Optimum extraction was observed at 60% solvent concentration at 4°C for 48 hours. The optimized anthocyanin extract exhibited maximum absorbance of 2.831 at 530 nm. Pre-pigment extraction steam blanching revealed the extract from banana bracts pre heat treated at 93°C for 6 minutes as the most stable pigment as studied for a period of 14 days compared to the control and other steam blanching treatments of 90°C-95°C for 3-6 minutes. The effect of pH-heat treatment on the stability of the extracted pigment was also investigated, it was analyzed for extract stability under pH-heat treatments of pH3-5 at temperatures of 30°C -70°C for 5 minutes, this revealed high extract stability when heat treated at pH 3 and 30°C. However, there was no significant difference in the spectrophotometric absorbance for pigment treated at pH 3 and 30°C and pH 3 at 50°C signifying high stability to heat when heat treated at low pH than at high pH ranges. Yoghurt containing 5% extract was the most acceptable (n=40 panelists) compared to other yoghurt-banana bract pigment formulations and much comparable to commercial brand straw berry yoghurt. Banana bract extracts can be used as a potential source of natural food colorant.