Influência dos sistemas de produção agrossilvipastoril e convencional na composição do leite e nas propriedades físico-químicas e sensoriais do iogurte natural integral

Abstract

The diet of dairy cows adopted in production systems is a determining factor both for its antioxidant capacity and for the composition of the milk and the physicochemical properties of the elaborated dairy products. Therefore, their quality characteristics depend, among other factors, on the food management followed in milk production systems. The objective of this work was to evaluate the influence of agrosilvopastoral and conventional production systems on milk composition and on the physicochemical and sensory properties of natural full-fat yogurt. In the first experiment, the influence of agrosilvopastoral (ASM) and conventional (CSM) production systems on the antioxidant capacity of the diet of dairy cows and the interference of drought on milk composition were evaluated. 21 animals were evaluated, 6 in the ASM system and 15 in the CSM, for 180 days. The diet in the ASM system was composed by 85% of low pastures: grasses, legumes and euphorbiaceae and 15% of concentrate: corn, wheat and soybean bran in the proportion 3:3:2 (Kg). In the CSM system, the diet was composed of 60% of grasses: tifton, brachiaria (Brachiária brizantha) and elephant grass and 40% of concentrate based on corn, soybean and wheat bran, in addition to mineral salt in the proportion of 4.5:3:2.2:0.3 (Kg). In the evaluation of the antioxidant profile of the diets of lactating cows, it was shown that the diet of the agrosilvopastoral system (ASM) presented higher antioxidant capacities and total phenolic content when compared to the diet of the conventional production system (CSM). It was confirmed that the chemical composition of milk and lipids were equivalent between treatments, being different only in the quantification of some compounds according to the production periods evaluated. The objective of the second experiment was to evaluate the impact of agrosilvopastoral and conventional milk production systems on the physicochemical and sensory properties of natural full-fat yogurt. Shelf life analyzes were carried out in the period of 28 days and the characterization of the physicochemical and sensorial profile. Agrosilvopastoral natural whole yogurt (NYA) obtained higher contents of total solids (fat, proteins, total carbohydrates and ash) and phosphorus and selenium minerals, greater reflection in the yellow color and more saturated tone, characterized by its higher fat fraction in the extract dry, in addition to its high protein content and low moisture that resulted in greater firmness and gumminess. In the sensorial analysis, both treatments were well accepted by the tasters. In the end, their intention to consume emerged, demonstrating that they would often eat yogurts, a reflection of the good acceptability index. Therefore, the agrosilvopastoral system is an important sustainable alternative for milk production, which is based on offering a healthy diet to the dairy herd through its antioxidant potential and total phenolic content, with recognized milk chemical composition and quality properties of yogurt, which obtained a good acceptability index evaluated by the tasters.