ABSTRACT

This study investigated the changes in nutrients that occurred at room (26+2℃) and refrigeration (4℃) temperatures after fermentation of castor oil bean. A portion of locally made ogiri was used as inoculum for the production of ogiri which was fermented for 96 h. The “ogiri” produced was divided into two parts. One part was kept at room temperature (26+2°C) for 96 h, while the other part was kept in a refrigerator (4^oC) for 96 h. Sub-samples were collected from the refrigerated sample and from the room temperature sample and analysed to monitor the changes in pH, TTA, TVC, proximate composition and amino acids contents every 24 h starting from 0 h after fermentation. The results obtained showed that the pH of the “ogiri” kept at room temperature increased significantly from 7.14 – 8.48 while the “ogiri” sample kept in the refrigerator did not show significant increase in pH (7.12 – 7.14) over the 4-day monitoring period. The TTA of the “ogiri” at room temperature decreased significantly (0.51- 0.27%) throughout the study period, whereas the TTA of “ogiri” in the refrigerator decreased slightly (0.51 – 0.49%). For the sample at room temperature, there was a slight decrease in moisture content (27.30 - 26.65) and a significant decrease in ash content (2.86 - 2.23%) respectively but fat content (47.25 – 53.16%) and protein content (22.17 – 27.66%) showed progressive increases respectively. There was also a significant decrease in the carbohydrate content (24.37 – 15.74%). Similar trends of nutrients changes were observed in the refrigerated sample but there was higher decrease in moisture content (27.30 - 26.04%) and a slight decrease in ash content (2.86 – 2.50%). The fat content increased from 47.25 - 48.63 and protein content increased from 22.17 - 26.62% while  carbohydrate content decreased from 24.37 – 19.45%.All the essential amino acids (Leucine, Lysine, Isoleucine, Phenylamine, Tryptophan, Valine, Methionine, Histidine, Threonine) and non-essential amino acids (Proline, Arginine, Alanine, Glutamic acid, Glycine, Serine and Aspartic acid) in both samples showed progressive increase within the period of study. However, higher increase was obtained in the samples kept at room temperature than for the sample kept in the refrigerator. The mean total amino acid content (essential and non-essential) was lower than the FAO/WHO stipulated standard values. However, some amino acids in the samples were higher than their reference values.