Abstract:
In this research, MDCM was initially prepared for protein hydrolysate production by washing with 0.5% sodium bicarbonate-tap water or by protein precipitation, and their proximate compositions and yields analyzed. Production of protein hydrolysates from the two types of raw material was carried out by varying bromelain (1600 GDU) at 0.25-1.25% dried weight, hydrolysing temperature at 40-60 ํC, pH at 5.5-7.5 and hydrolysing time at 3-9 hours. The degree of hydrolysis (DH) and odor score were used to select the most appropriate condition. The resulting hydrolysates were concentrated on a rotary vacuum evaporator at 50 ํC and 60 ํC and their proximate compositions assessed. Appropriate formula for thick chicken sauce was simulated by varying quantities of each hydrolysate type at 10-30%, sugar at 25-40% and soy sauce at 30-50%, using the sensory quanlities of the resulting sauces and the water convolvulus, stir-fried with the sauces as selecting criteria. The proximate compositions of the washed-MDCM and extracted-protein found were 73-88% (dried weight) protein, 1-17% (dried weight) fat, 83-88% moisture and 0.7-0.9% ash. The yields obtained were 53.77% for extracted-protein and 38.16% for washed-MDCM. Appropriate conditions found for enzymic hydrolysation of the two types of raw material were pH at 6.5, 0.75-1.00% dried weight of the enzyme, 60 ํC and 3-6 hours. The 60 ํC was selected to evaporate water from both hydrolysates and their compositions found were 48-49% protein and 0-1% fat. The formula selected for the thick chicken sauce was composed of 23% hydrolysate, 33% sugar and 44% soy sauce. The resulting sauces contained 16-17% protein and 0-1% fat. The sauce samples with and without potassium sorbate can be stored for at least 3 month with decreasing of their viscosities but the sensory qualities still being acceptable. Stir-fried water convolvuluses seasoned with the four sauce samples were acceptable throughout the whole storage period.