Garbage enzymes were produced based on the formulation of three parts of fruit peels, one part of brown sugar and ten parts of water were mixed together (The Star, 2009) and fermented in 5L plastic bottle at room temperature for three months.
CHARACTERISTICS OF GARBAGE ENZYME.
The progression of fermentation of the fruit discards showed a reduction of pH with times, 3.15 for GE while 3.78 for CGE. Odunfa, (1985) attributed the significant reduction of pH to acid production during fermentation. In our study, the fall of pH could be attributed to the organic acids produced during fermentation by microorganisms. The pH value of GE produced was different with CGE. This might be due to the fruit types used in the production and fermentation practice was different. For instance, the fruit peels collected were cleaned with distilled water while the commercial producer would ferment them right away without washing. Moreover, natural fermentation is spontaneous and uncontrolled thus resulting in a product of variable quality.
Total microbial counts were detected to be about 5 log CFU/ml by the end of fermentation for both GE and CGE. On the other hand, total yeast and mold count was really low for both GE and CGE. From the observation morphology of the colony on the DRBC agar, only yeasts were present in our fermentation products.
Fruit peels collected were cleaned using only distilled water, and were not subjected to further pre-treatment before fermentation. Spontaneous fermentations are generally uncontrolled and the product microbiota is inconsistent. The fermentation mainly relies on the microflora from the fruit surfaces and to some extent from the utensils used during the fermentation process. The diverse microbial flora on fruit surfaces may play an important role during the spontaneous fermentation process (Fleet, 2003). The types of microorganisms detected include coliforms, lactic acid bacteria, and yeasts (Mbugua, 1985). Yeasts usually occur in association with lactic acid bacteria in most indigenous fermentation (Sanni, 1993; Gobbetti et al., 1994; Caplice and Fitzgerald, 1999; Fleet, 1999; Jespersen, 2003; Nout, 2003).
Table 3. pH, soluble solids values and microbial counts of garbage enzymes
Sample pH Total microbial counts
(log CFU mL -1) Total yeast and mold counts
(log CFU mL-1 )
GE 3.15 ± 0.10 4.88 ± 0.20 0
CGE 3.78 ± 0.01 5.42 ± 0.42 0.10 ± 0.66
GE, garbage enzyme; CGE, commercial garbage enzyme.
EFFECTIVENESS OF GE AS DETERGENT
Washing analysis was carried out to determine the effectiveness of the garbage enzymes in removing ketchup, blood and coffee stains which are the common household stains from the cotton fabrics by measuring the lightness of the cloths using a colorimeter. Lightness is a dimension of the colour of an object by which the object appears to reflect more or less of the incident light. Table 4 depicts that detergent supplemented with garbage enzyme (D + GE and D + CGE) resulted in better stain removal from...