Stabilization and Preservation of a Traditional Sorghum-based Fermented Beverage

Traditional fermented cereal beverages such as Obushera from sorghum and/or millet are commercialized owing to their popularity among consumers. However, Obushera separates into two phases after processing, which could be mistaken for spoilage. Additionally, Obushera has a limited shelf life of 4–7 days at room temperature. The objective of this study was to assess the potential of various stabilizers and preservatives for the production of acceptable shelf-stable Obushera.

Effects of seven treatments of 1) 0.4% xanthan gum, 2) 0.4% carboxymethyl cellulose, 3) Lactobacillus rhamnosus yoba, 4) 0.4% xanthan gum and Lactobacillus rhamnosus yoba, 5) 0.4% carboxymethyl cellulose and Lactobacillus rhamnosus yoba, 6) 0.4% xanthan gum and 0.4% carboxymethyl cellulose and Lactobacillus rhamnosus yoba, and 7) a control (no stabilizers) on sedimentation rate were assessed within 120 h at room temperature. Effects of four treatments of 1) pasteurization (90 °C for 10 min) and 0.25% xanthan gum, 2) pasteurization and 0.25% xanthan gum and 0.2% potassium sorbate and 3) pasteurization and 0.25% xanthan gum and 0.1% sodium-benzoate and 4) control (pasteurized with no additives) on shelf stability and consumer acceptability were investigated.

Treatments with xanthan (sedimentation index of 0–25%) for stabilizing Obushera were significantly (p < 0.05) more effective than those with no xanthan (sedimentation index of 49–67%). Xanthan (0.25%) significantly (p < 0.05) improved consumer acceptability of Obushera. All preservation treatments (p > 0.05) prolonged the shelf life of the beverage up to four months. No microbial growth was detected in the products during storage while pH (3.7–4.0) and acidity (0.5–0.6%) did not change significantly (p > 0.05). All products were acceptable during storage.

Obushera and related products can be stabilized and preserved using xanthan (0.25%) and pasteurization (90 °C for 10 min) with no added preservatives.