Analysis of milk composition and acceptability of mozzarella cheese from Kenyan Toggenburg dairy goats and their crosses with Galla goats

Abstract

In Kenya, most studies involving exotic dairy goats and their cross breeds with indigenous goats have majorly focused on milk yield, kidding and growth rates with little information on the technological performance of the milk from cross breeds. In this study milk from the Toggenburg and its cross breed with Galla goat was evaluated fortnightly for composition and its capability for mozzarella cheese making over a three months lactation period. Samples of milk were analyzed for composition using official analytical methods (AOAC, 2000). Milk coagulation time was determined using procedure by Arima and Iwasaki, (1970). Mozzarella cheese was prepared following procedure by Mistry and Koskowski, (1997). The cheese yield was determined on the second day as a percentage of the cheese milk used during and its composition analyzed. Sensory attributes of the cheese were evaluated using procedure by Murray, et al., (2001). Data obtained was analyzed using Statistical Analysis System. Means were separated using Least Significant Differences and for all analysis, statistical significance was accepted at the P  0.05 level of probability. Differences were observed in milk composition being 33.32±0.12, 2.85±0.10, 0.93±0.02 and 10.44±0.52 in Toggenburg and 3.87±0.13, 3.51±0.18, 0.82±0.03 and 11.68±0.35 in cross breeds for fat, protein, ash and total solids respectively. Coagulation time was significantly elongated in cross breed milk. Mozzarella cheese yields was higher at 18.66±0.88 for Toggenburg and 15.23±0.98 for the cross breed. Cheese components were higher in Toggenburg at 20.28±0.29 and 24.44±1.21 compared to 19.41±0.19 and 22.75 ±1.51 in cross breed for protein and fat respectively. Weak positive correlation was observed between cheese yield and both protein (0.28) and fat (0.42) in cross breed while Toggenburg had weak correlation value (0.38) for protein. Total solids showed medium positive correlation with cheese yield at 0.65 and 0.64 for cross breed and Toggenburg respectively. Based on a 5-point hedonic scale, cheese acceptability scores were 3.80 for Toggenburg and 3.63 for cross breed while descriptive sensory profiles indicated differences in flavour and texture. Significant effect of the stage of lactation was observed from individual genotypes on the parameters evaluated. From the study, it is concluded that milk from the Toggenburg is superior in terms of Mozzarella cheese making properties and cheese acceptability. The study recommends determination of casein variants and fatty acid profiles in milk from both genotypes as they significantly influence cheese making and acceptability.