Physicochemical Changes of Commercial “Kounou” During Short Term Storage at Room and Refrigerated Temperatures

Abstract

Fermented cereal-based drinks as “kounou” are among the most popular indigenous beverages in Northern Cameroon. Because they are made in a primitive way, they are ready to be served while still actively fermenting. Therefore, some physicochemical properties of “kounou” were tested in the current study during 4 days of storage at room and refrigerated temperatures. Samples of “kondourkou” a sub type of “kounou” were purchased from local producers located in the Far North region of Cameroon. During storage at 28 ± 2°C and 4 ± 1°C, total sugars, pH, total acidity, alcohol content, total soluble solids, dry matter, total dissolved solids, and conductivity of samples were measured in triplicate using standards procedures. The results showed that pH decreased from 3.34 to 3.16, and 3.65 to 3.4 after storage at room and refrigerated temperatures, respectively. The decrease in total sugar (30.3%-12.1%) and soluble solids (7.26-4.89°Brix), as well as increase in titratable acidity (0.26%-0.36%) were significant for samples stored at ambient temperature. While no significant changes in all these parameters were revealed for samples stored at cold conditions (54.8%-37.9%; 8.79-8.13°Brix and 0.18-0.25%, respectively). Dry matter and total dissolved solids were lower in samples stored at room temperature (from 10.3-11.2% and 841.9-1002 mg/L, respectively) than those kept under refrigeration (from 12.15 to 12.5% and 1061.2-1231.7 mg/L, respectively). Alcohol content and conductivity were respectively in the range of 3.5-2.35% and 1692.4-2012.5 mg/L for samples stored at room temperature, and 3.18-3.37% and 1692.4-2205 mg/L for those kept under refrigeration. Principal component analysis revealed that samples stored under refrigeration were structured in two sub-cluster, the first formed by those stored for 1 and 2 days and the second including those kept for 3 and 4 days. While samples left at room temperature were separated into three sub groups, those stored for a day, 2 and 3 days, and 4 days.  Finally, it would be appropriate to consume refrigerated “kounou” as well as commercialize and/or store it under refrigeration.