stabilization and preservation of a traditional sorghum-based fermented beverage

Background and objectives: 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. materials and methods: 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. results: 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. conclusions: obushera and related products can be stabilized and preserved using xanthan (0.25%) and pasteurization (90 ˚c for 10 min) with no added preservatives.