Enrichment of ice cream with natural colorants and antioxidants from purple sweet potato

Abstract:

What if the vivid purple hue that attracts consumers to synthetic-dyed frozen desserts could come instead from a vegetable that also supplies antioxidants? Purple sweet potato (Ipomoea batatas) is rich in acylated anthocyanins with heat and pH stability superior to most fruit-derived pigments, making it a promising natural colorant for dairy products. This research incorporated aqueous purple sweet potato (PSP) extract at 0, 2, 4, 6, and 8% (v/v) into a vanilla ice cream mix and evaluated the effect on colour, antioxidant activity, physicochemical properties, and sensory acceptance. The work was performed at the Department of Animal Products Technology, Federal University of Viçosa, Viçosa, during June-September 2023. The 6% PSP formulation achieved the most favourable balance: strong purple colour (a* = 12.3), high DPPH radical scavenging (49.2%), acceptable overrun (78.4%), and the top sensory score (7.8/9). Higher inclusion (8%) darkened the ice cream excessively and introduced a mild earthy off-note. PSP extract at 6% can replace synthetic colourants in ice cream while adding measurable antioxidant value.