Anthocyanin-Rich Sweet Potato (Ipomoea batatas L.) Beer: Technology, Biochemical and Sensory Evaluation

Abstract

The global consumption of beer is increasing and consumers are interested in varieties rather than the only traditional beer prepared from malted barley; hence, it is necessary to search for unique potential substrates for beer production. The current study focuses on the preparation technology and the biochemical and sensory characteristics of beer samples by using purple sweet potato (PSP) (Ipomoea batatas L.) flakes as ingredient. Anthocyanin-rich beer was developed by fermenting a combination of PSP flakes and grist (crushed malt) prepared from barley through Saccharomyces cerevisiae without altering the originality of beer preparation. Among the beer samples (prepared from 0, 30, 50 and 100% PSP flakes as adjunct), the beer prepared from 30% PSP flakes + 70% grist was the best as recommended by the sensory panelists, followed by the beer prepared from 50% PSP flakes + 50% grist. The beer prepared with 30% PSP flakes had the following compositions: total soluble solids, 3.57 °Brix; starch, 0.77 g/100 mL; total sugar, 6.93 g/100 mL; specific gravity, 1.02; pH, 3.05; titratable acidity, 0.76 g tartaric acid/100 mL; lactic acid, 0.10 mg/100 mL; phenol, 0.21 mg/mL; anthocyanin, 5.10 mg/100 mL; ethanol, 3.77% (v/v) and DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging activity, 6.31% at a dose of 250 μg/mL. Strong loading of anthocyanin pigment (+ve), phenol (+ve) and the DPPH scavenging activity (+ve) on PC1 signifies the health attributes of the beverages. Practical Applications Anthocyanin-rich sweet potato beer is a novel product that beholds antioxidative properties, unique purple color and low alcohol content (3.77%). The product is well accepted by the sensory panelists. The technology will provide pathway to use sweet potato as ingredient for beer making in large scale. The cheaper cost of sweet potatoes and the simpler technology will attract the brewers to adopt the technology, which can help in the socioeconomic upliftment of several tribal communities of Asia and Africa as they depend on sweet potato cultivation for their livelihood.