You have no items in your shopping cart.
ABSTRACTThis research work examined the changes in pH, conductivity, refractive index, and uv/visible spectra of some stored food samples( powdered milk, soya bean, palm oil and groundnut oil). Fresh samples of palm oil, groundnut oil, soya bean oil and powdered milk were acquired at Uselu market, Egor Local Government Area of Edo state and stored in clean bottles at room temperature. Physical parameters involving pH, conductivity, uv/absorbance and refractive index measurements were carried out on the stored food samples for 8 weeks. Values of pH for palm oil and groundnut oil showed consistent decreases (increasing acidity) over time reaching the lowest value of (3.50±0.04 and 3.45 ± 0.10) respectively at week 8.The mean pH value of milk decreased slowly from 6.68 in week 1 to 6.20 in week 8 showing a slight increase in acidity. Electrical conductivity for soya bean oil increased with time and reached a peak value of 132.7 at the fourth week followed by a decrease from week 5 to 8. The same trend was observed for palm oil, groundnut oil and milk samples. Uv absorbance measurements value for palm oil had the highest value of (0.74±0.05) in the first week while soya bean oil had the least (0.49±0.00). In the fifth week palm oil had a value of (0.91±0.01), groundnut oil also had a value of (0.70±0.00) while soya bean oil had the least value of (0.42±0.00). Values of refractive index for palm oil decreased from 1.4682 in the first week to 1.4637 in the eight week. For soya bean oil, the refractive index showed a large decrease from week 1 to week 2 (1.4787 to 1.4735) after which the value remained stable till week 8. The refractive index of groundnut oil showed variations (increase and decrease)but the value remained fairly constant from start of storage till the last week of storage. The changes in these physical indices of quality suggest that the samples will undergo deterioration which have to be managed properly for improved shelf-life.
