Effects of different autoclaving parameters on the nutritional compositions of raw milk samples.

Abstract

As milk provides a substantial amount of vitamins and minerals in relation to its energy content, it is considered a nutrient dense food.The difference and changes in the nutritional compositions (Protein, fat, carbohydrate, moisture content, ash content, fibre content, magnesium and calcium) of White Fulani, Sokoto Gudali and mixture of the two breeds were investigated before and after autoclaving of milk samples in glass, aluminium and stainless steel containers at various temperatures of 110℃,121℃and 130℃ with autoclaving time of 10minutes, 20 minutes and 30 minutes. The heat treatment was done using MA DONAX YX-280A Vertical Column Autoclave of 18Litre capacity of pressure of 0.14MPa – 0.165MPa.The results were evaluated using ANOVA at p≤0.05. The significant difference was evaluated using the DNMRT.Chemical test carried out on the samples before and after autoclaving showed significant variation in (Protein, fat, carbohydrate, moisture content, ash content, fibre content, magnesium and calcium content (p<0.05) after autoclaving. Carbohydrate content in milk increases at 30mins for all the temperature and materials, carbohydrate content in white Fulani 9.56% is higher than other milk source. Moisture content reduced for all conditions with no preference to any autoclaving parameter. Both calcium and magnesium reduced for all milk samples (12.38%, 12.92%, 12.83%) and (7.90%, 5.89%, 4.24%) respectively. At higher temperature of 130C the fat content in milk decreases in both glass material and stainless steel which makes aluminium a preferable storage material.