Effect of Using Renin Enzyme and Plant Enzymes on Time of Milk Coagulation, Yield, Composition and Sensory Characteristics of White Soft Cheese

Abstract

This research was conducted to study the effect of using renin enzyme and two other plant enzymes on the coagulation time of milk, yield, composition and sensory characteristics of produced cheese. The renin enzyme was used as control. The plant enzymes were extracted from Solanum dubium (Jibeen) and Calotropis procera (Osher) plants. Plant enzymes were added to the milk in 3 concentrations (50%, 75% and 100%). Coagulation time, yield, composition and sensory characteristics were assessed during the lactation period, which was divided into 1st., 2nd. and 3rd. stages. (1st. 2nd. and 3rd. two months after calving) and for the whole lactation period. The total number of cheese samples used was 216 for the different treatments. Average coagulation time for whole lactation period and all treatments when using renin, Osher (50%) and Jibeen (50%) enzymes recorded, was 97.33± 4.62, 124.37± 5.88 and 96.29± 4.96 minutes respectively. Using renin, Osher (75%) and Jibeen (75%) enzymes, coagulation time obtained was 80.37± 3.54, 113.62± 7.29 and 87.75± 2.23 minutes respectively and 79.45± 3.65, 108.83± 5.62 and 85.95± 4.95 min. for renin, Osher (100%) and Jibeen (100%) enzyme respectively. A significant difference (p<0.05) was detected between the average coagulation time for all stages, whole lactation period and all treatments. Coagulation of the milk by renin enzyme requited less time, while much time was required by Osher enzyme compared to Jibeen enzyme. The variation in time required by the different coagulants was related to the type of enzyme used, chemical composition of milk, method of coagulation applied, as well as the clotting activity of the milk. The average total yield of soft cheese obtained from 5kg cow milk, when using renin, Osher (50%) and Jibeen (50%) enzymes for the whole lactation period and all treatments was 913.5± 8.66, 635.9± 14.09 and 662.25± 15.58 g respectively. For renin, Osher (75) and Jibeen (75%) enzymes was 944.3± 32.89, 697.8± 16.99 and 729.3± 41.8 g. respectively. For renin, Osher (100%) and Jibeen (100%) enzymes, the average cheese yield was 916.0± 11.54, 788.7± 16.70 and 804.3± 9.55 g respectively. The average total cheese yield showed a significant difference (p<0.05) for all stages, whole lactation period and all treatments. Renin coagulation resulted in good cheese yield, followed by Jibeen and Osher. Differences in cheese yield was affected by many factors, e.g. milk composition, enzymes and type of enzyme used for coagulation, production of weak curd produced by plant enzymes and others. For whole lactation period and all treatments, the average protein % was found as 14.42± 0.44, 11.96± 0.46 and 13.44± 0.74 when using renin, Osher (50%) and Jibeen (50%) enzymes respectively, 14.26± 0.36, 12.14± 0.35 and 13.61± 0,60 for renin, Osher (75%) and Jibeen (75%) enzymes respectively and 14.36± 0.39, 12.02± 0.26 and 13.55±± 0.42 for renin, Osher (100%) and Jibeen (100%) enzymes respectively. The average fat % obtained was 20.06± 0.84, 15.99± 0.75, and 16.95± 0.80, for renin, Osher (50%) and Jibeen (50%) enzymes respectively/. An average fat % of 19.97± 0.80, 16.00± 0.59 and 18.35± 0.44 obtained for renin, Osher (75%) and Jibeen (75%) enzymes respectively. Also a content of 20.39±0.57, 15.91± 0.40 and 18.54± 0.31 % for renin, Osher (100%) and Jibeen (100%) enzymes respectively. The ash % when using renin, Osher (50%) and Jibeen (50%) enzymes obtained, was 4.27± 0.37, 3.27± 0.31, and 3.47± 0.26 respectively. Using renin, Osher (75%) and Jibeen (75%) enzymes, the ash % 4.07± 0.28, 3.04± 0.21, and 3.47± 0.26 respectively, and 4.12± 0.24, 3.04± 0.52 and 3.25± 0.16 for renin, Osher (100%) and Jibeen (100%) enzyme respectively. Also a significant variation (p<0.05) was detected betweenthe means of the milk components (protein, fat, ash %) for the different stages, whole lactation period and all treatments. The milk components showed low percentages, when plant enzymes were used compared to renin enzyme, Jibeen enzymes gave higher average % rather than Osher enzyme. In general, coagulating the milk with plant enzymes resulted in a decrease in the total solids % of the soft cheese in association with the type of coagulant used, variations in the contents of the milk components in addition to the method of coagulation used. According to panelists the points scored for flavor were 9.00± 0.63, 5.87± 0.62 and 6.62± 0.69 using renin, Osher (50%) and Jibeen (50%) enzymes respectively. Using renin, Osher (75%) and Jibeen (75%) as 8.83± 0,86, 5.62± 0.76 and 6.62± 0.76 respectively, and 8.79± 0.77, 5.91± 1.28, and 6.87± 0,74 when renin, Osher (100%) and Jibeen (100%) enzymes were used. Concerning the taste, the points attained when using renin, Osher (50%) and Jibeen (50%) enzymes, 8.08± 0.71, 6.25± 0.82, and 7.20± 0.88 respectively. 8.54± 0.77, 5.83± 0,76 and 6.58± 0.71 when using renin, Osher (75%) and Jibeen (75%) enzymes respectively, and 8.45± 0.88, 5.79± 0.83 and 6.50± 0,78 for renin, Osher (100%) and Jibeen (100%) enzymes respectively. For texture, the points given when using renin, Osher (50%) and Jibeen (50%) enzymes were 8.97± 0.77, 5.83± 1.04 and 7.12± 0.97 respectively. Scored points when using renin, Osher (75%) and Jibeen (75%) enzymes were 8.66± 0.70, 5.91± 0.71, and 8.12± 0.67 respectively, and 8.58± 0.88, 5.97± 0.72, and 8,08± 0.71 for renin, Osher (100%) Jibeen (100%) enzymes respectively. Also a significant difference (p<0.05) was detected between the average points given for flavor, taste and texture for all stages, whole lactation period and all treatments. Renin cheese scored the highest points for the sensory characteristics followed by Jibeen cheese. Osher cheese scored the lowest points. Variation in flavor, taste and texture of the soft cheese produced by the different coagulants may be related to the type of enzymes used for coagulation and their concentrations, chemical composition of the cheese milk and also the decrease of proteolytic activity of plant enzymes, due to increase of acidity when starterculture was added. Based on the results obtained, Jibeen enzyme may be considered as an alternative for other enzymes, when the availability, especially renin enzyme is restricted for one reason or others.