Abstract

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The potential of three preservation techniques: the use of two chemical preservatives; sodium benzoate and sodium metabisulphite, pasteurization and refrigeration for the preservation of kunun-zaki was evaluated. The treated samples were stored for four weeks. Microbiological analyses and assay of physico-chemical parameters such as pH, titratable acidity, sugar content, mineral content and alcohol content were conducted at three-day intervals for the duration of storage. Changes in the quality attributes and overall acceptability of the stored samples were also monitored over the period. Results obtained indicate the presence of seven organisms comprising five bacteria and two yeasts in the kunun-zaki samples. They were Bacillus subtilis, Bacillus cereus, Leuconostoc mesenteroides, Micrococcus varians, Lactobacillus fermenti, Saccharomyces cerevisiae and Candida albicans. Bacterial counts ranged from 0.89x106 to 14.9xl06 CFU ml/1 while fungal counts ranged from 0.98xl06 to 16.8xl06 CFU mL-1. The results of physicochemical analyses carried out on pre-storage showed that kunun-zaki had pH, titratable acidity, sugar content and alcohol content of 5.93, 0.137 ml, 6.40% and 0.0% respectively. There was a general reduction in pH, sugar content and mineral content of the kunun-zaki samples, with a general increases in the titratable acidity and alcohol contents during the storage period. Sensory evaluation tests indicated that kunun-zaki samples preserved using chemicals and stored at 5°C were acceptable to the 27th day of storage. This study revealed a new possibility of storage stability of kunun-zaki, without significantly affecting the organoleptic properties (p<0.05) for four weeks with combined processes of pasteurization, refrigeration (5°C) and the use of chemical preservatives.

Keywords: Cereal beverage, Chemical preservatives, Kunun-zaki, Pasteurization, Refrigeration.