Process optimization of milk coagulant extraction from latex of Carica papaya for production of pre ripened cheese A
Creators: name: Amanu, Mitiku
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2015

description: The present work was intended to optimize the papain extraction parameters (drying temperature, ethanol to latex ratio, and ethanol concentration) and cheese production parameters (temperature, pH, papain amount)at which maximum milk clotting activity(MCA) and water solubility index (WSI) of papain enzyme and maximum yield and hardness of cheese respectively was achieved using response surface methodology. Hence maximum MCA of 528.85unit/ml and WSI of 85.45% were achieved at drying temperature (47.98oc), ethanol: latex ratio (1.04) and ethanol concentration of (50.69%v/v). Similarly maximum yield of 9.88% and hardness of 6.84N were obtained for cheese samples at temperature, pH, and papain amount of 70.58oc, 7 and 30.46ml respectively. Optimization results indicated that increased levels of the selected parameters of papain extraction decreased the response variables in charge, while increasing levels of cheese production parameters increased the corresponding response variables of cheese production. The physico chemical analysis results of papain produced at optimum process conditions showed that (moisture, protein, fat, fiber, ash, Zn, Fe, Ca)were 6.95%, 71.2% , 8.95% , 0.22% ,12.21% , 0.87mg/100g , 4.57mg/100g , and 1949.39mg/100g respectively, while the percentage purity results was 80.10% respectively. On the other hand; fat, protein , lactose total ash and energy value of pasteurized milk were found to be 2.7%,3.50%,4.70%,0.66%, and 57.10 kcal/100g respectively with pH and titratable acidity were 7.02 and 0.13. As far as the cheese samples (samples 1, 2, and 3);those produced at maximum, minimum, and optimum cheese production parameters respectively ,are concerned their proximate composition ranged from56.65 to 68.77%, 13.22 to 16.41%, 8.43 to 10.21%, 1.64 to 2.42% , 0.32 to 2.36% , 6.79 to10.99%,156.55 to 201kcal/100g,5.49to7.03mg/100g,25.95 to31.88mg/100g and 9.33 to 10.47mg/100g for moisture content ,crude protein, crude fat ,total ash, crude fiber, total carbohydrate, energy value, Zn, Ca, and Fe respectively. The nutritional value of sample 3 appeared to be higher on the macro nutrients than the other two due to the effect of optimization. While, physico-chemical results (pH, Titratable acidity, Color indices (L, a, and b)) ranged from 6.08 to 6.19, 0.32 to 0.41%, 81.39 to 90.28, 1.30 to 1.80, and 11.98 to 17.44 respectively. Moreover, microbiological analysis results of the cheese samples for aerobic plate count and coli forms varied from 5x102 to 4.8x105cfu/g. unlike sample1, where mold and fecal coli forms were detected, these microorganisms were below the detection limits in samples 2 and 3. Finally, the sensory analysis varied from 7.8 to 8.4, 4.5 to 7.6, 6.3 to 7.2, 4.2 to7.6, 5 to 7 and 4.2 to7.8 respectively. Generally the partially purified papain enzyme and the cheese samples made using papain enzyme were of good quality, especially the ones made at the respective optimum process conditions. Key words: Milk clotting activity, papain extraction, pre-ripened cheese, Response surface methodology, etc.