Due to the high rate of food spoilage of mostly perishable food, spices are being used to preserve food, which is found to be a source of natural antioxidants and has also been proven to replace the chemical preservatives used. This work aimed at testing the efficacy of Clove in preventing the spoilage of fried soybeans cake (Tofu). Three (3) different spice concentrations used were 0.25 0.5, and 0.75 g respectively, with positive and negative controls. The antioxidant and anti-inflammatory ability of the spice was evaluated using DPPH radical scavenging, reducing power, and membrane stabilization activity. The proximate composition was evaluated using the standard procedure of AOAC. The microbiological quality of the food samples treated with the spice was assessed using standard aerobic plate count, total coliform, and fungal count. Storage stability and storage challenge tests were performed according to standard procedure. The sensory evaluation was conducted using a 9-point hedonic scale to rate consumer preference. One-way ANOVA was used to find significant differences at a significance level of ≤0.05. Clove spice was found to possess a high level of antioxidants (88.10-82.00%) and (88.00-80.00%) for DPPH Radical scavenging activity, reducing power assay and anti-inflammatory content ranging from (60.40 - 38.00%) and (98.33-93.00%) for membrane stabilization test at heat induced and hypotonicity induced hemolysis respectively at different concentrations. The proximate compositions of the food sample treated with the spice indicate the increase in protein (68.00-64.00%) and fiber (2.50-2.10%) as well as the low moisture content (2.00-1.60%) of the food sample compared to the untreated one. The total bacterial and mold count shows a reduction in the number of colonies of the treated sample compared to the untreated one and with the fresh one compared to the spoilt sample. The coliform count indicates the absence of fecal coliform, and the count is within the acceptable limit. For the storage stability test, the spoilage rate of treated food samples decreases with an increase in the spice concentration for several weeks. The food samples treated with different concentrations were accepted by the panel of judges in terms of appearance, taste, texture, flavor, and overall acceptability. This study may help with information to various food industries on the application of clove to produce safe and effective food and processing the spice for commercialization as a natural preservative. Further research is needed on how to combine hurdles with spices to obtain a higher shelf-life.
Key words: Antioxidant, clove, coliform, food spoilage, preservatives, spices
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