Caracterização do leite e do queijo de cabras alimentadas com óleo de linhaça em substituição ao milho

Abstract

Dairy goat farming is a relevant activity for northeastern livestock. The search for food that improves the quality of milk and consequently by-products has been sought by many researchers. Thus, with this study, the objective was to evaluate the physical-chemical quality of milk and cheese from goats fed diets containing different concentrations of flaxseed oil to replace corn. The experiment was conducted in the laboratory of Goats and Sheep of the Center for Human, Social and Agrarian Sciences belonging to the Federal University of Paraíba. Eight multiparous goats, Saanen breed, weighing 51 ± 8 kg and 67 ± 18 days of lactation were used. The animals were kept in a confinement system for 60 days. The goats were randomly distributed in a Latin square (4x4), according to the concentrations of inclusion in the diet, of flaxseed oil. The treatments were: T1: control; T2: 1% replacement; T3: replacement of 2% and T4: replacement of 3% of corn with linseed oil. Milk samples from each animal were collected twice a day, at regular times, during the three days of data collection for each period for subsequent physical-chemical analysis and fatty acid profile by means of gas chromatography. The economic feasibility analysis was based on the classification of operating costs considering the values consumed by the animals for the ingredients and the expenditures on veterinary products for milking hygiene, medicines and labor. The milk from each treatment was used to make the cheeses. Physical-chemical analyzes were performed at the Food PhysicsChemistry Laboratory CCHSA/UFPB. After processing, the yield of each type of cheese was expressed as the weight of fresh cheese in grams obtained from 10 liters of milk used. The instrumental color was determined using a Minolta colorimeter, model CR-300, using the CIELAB system. The addition of flaxseed to the animals' feed promoted a linear increase in density. Higher values of density in milk were verified when the animals consumed diets containing 2% and 3% of flaxseed oil in the diets. Similar changes were observed in the levels of lactose and non-fat solids. The other variables related to the physical chemistry of milk did not change. There were significant changes in the lipid profile of milk with a decrease in saturated fatty acids, an increase in monounsaturated fatty acids and an increase in polyunsaturated fatty acids. The cheese produced from the milk in which the animals consumed linseed oil was changed linearly only in the pH and color values.