Qualidade do queijo e do leite de vacas F1 Holandês x Zebu alimentadas com palma forrageira associada a diferentes volumosos

Abstract

The objective of this study was to evaluate the effects of indian fig opuntia (Opuntia ficus indica Mill) in association with different green fodders on the diet of F1 Dutch x Zebu cows, on the chemical and sensorial quality, and fatty acid profile of milk and Minas fresh cheese. The treatments were defined as follows: (T1) sorghum silage as the fodder; (T2) Diet with 50% of sorghum silage replaced by Opuntia ficus sp; (T3) Diet without the inclusion of the spineless cactus, with elephant grass as the fodder; (T4) Diet with 50% of elephant grass replacement. Eight cows were used, with 72 ± 11 days of lactation at the beginning of the experiment. The experimental design was two simultaneous 4 x 4 Latin squares, with periods of 18 days, therefore, 14 days of adaptation and four days of data gathering. Milk samples, were collected and analyzed for chemical composition. On the fourth day of collection, the milk obtained from the cows was pasteurized for the production of the Minas Frescal cheese, which was weighed to determine the adjusted gross income, and analyzed for texture, chemical characteristics and consumer acceptance test (sensory evaluation). The milk urea nitrogen (MUN) had highest observed value (16.08 mg dL-1) in diets containing only elephant grass. The preference sorting test showed that the most preferred cheese was that without spineless cactus inclusion on the diet and with sorghum silage as the fodder, and the least preferred was that with 50% of the sorghum silage diet replaced by indian fig opuntia. In the acceptance test, for appearance, a higher grade was assigned to cheeses from the milk of cows fed with the diet containing only sorghum silage as bulk. When analyzed for consistency and flavor, lower grades were for the cheese of the treatment with elephant grass and indian fig opuntia. For overall impression, higher grades were given to the cheeses from the treatments with only silage or elephant grass. The other items evaluated in the chemical composition of milk and cheese were not influenced by diets. There was an effect of the diets on the sum of the saturated and monounsaturated fatty acids of the milk, presenting lower and higher values, in same order, with the diet containing elephant grass. The content of C16: 0 acid were lower in the diet with only elephant grass or sorghum silage as bulky. The concentration of C18: 0 was lower in the diets containing indian fig opuntia. Higher levels of oleic acid was observed with diets containing grass. Conjugated linoleic acid (CLA) was higher vi in the milk of cows fed palm. In the cheese, no changes were observed in the sum of saturated, monounsaturated and polyunsaturated fatty acids. However, lower stearic acid content was observed in cheese from cows fed with grass associated with palm, and lower CLA values for diets with silage as fodder. Regarding nutritional indices, differences were verified only in milk, which presented lower atherogenicity index and higher proportions of desirable fatty acids for diet with grass. The association of indian fig opuntia in 37.75% of the total diet with sorghum silage or with elephant grass did not changed the chemical composition of the milk and Minas Frescal cheese, however, it influenced the acceptance and preference test of the Cheese by consumers, as well as in the fatty acid profile of milk and Minas Frescal cheese, with a reduction in stearic fatty acid concentration and increase in CLA content.