Abstract The objective of this study was to prepare three donkey milk yoghurt formulations mixed with goat, cow and buffalo milk. The formulations were developed with 50% donkey milk and 50% cow, buffalo or goat milk. Concentrated mango pulp was added for flavouring. An evaluation was performed on the chemical composition of each milk sample and the formulated yoghurts. The donkey milk showed the lowest values for fat, protein, casein, total solids and non-fat solids. In turn, goat milk reached higher levels of fat and total solids. Furthermore, buffalo milk stood out with the highest values of protein and non-fat solids. Yoghurt made with donkey and buffalo milk showed higher concentrations of protein, lactose, total solids and non-fat solids. In contrast, the yoghurt that contained donkey and cow milk in its formulation obtained a higher fat percentage and a lower percentage of lactose, total solids and non-fat solids. The low content of fat and total solids in donkey milk, in addition to the structure of the casein micelles and small fat globules favor low consistency in fermented products. Thus, mixing donkey milk with milks from other animal species can result in better chemical composition and better consistency.

Abstract The aims were to evaluate the effect of breed on the genetic polymorphism kappa-casein, physicochemical composition of milk and Coalho cheese, and on cheese yield; and to evaluate the effect of different periods of storage on sensorial acceptance of the Coalho cheese obtained from milk of Guzerat, Gyr and Sindi cows. Twenty (20) cows of Zebu breeds were selected, from which it was obtained the frequency values of the genetic polymorphism kappa-casein. Milk were submitted to fat, protein, lactose, non-fat solids and total solids, electrical conductivity analysis and somatic cell count. Cheeses were submitted to fat, protein, total solids, pH, moisture and yield (g TS/L) analysis. Attributes appearance, aroma, texture and flavor were judged at the 1st, 25th and 46th day of storage. There was a total frequency of 0.70 for genotype AA, 0.30 for genotype AB. There was no significant difference in milk composition among the studied breeds. However, there were differences in the physicochemical composition (with the exception of the protein) and the yield of the cheeses, but all the breeds showed a similar real yield. It was found effect of the storage period on the cheeses sensory attributes in the different breeds, with the exception of the appearance. The milk of the Guzerat, Gyr and Sindi breeds constitute an excellent raw material for the production of curd cheese and ensures a satisfactory sensorial acceptance of the product at the 1st, 25th and 46th days of storage.

Resumen Los objetivos fueron evaluar el efecto de la raza sobre el polimorfismo genético de la kappa-caseína, la composición fisicoquímica de la leche y del queso Coalho, y el rendimiento del queso, así como evaluar el efecto de diferentes periodos de almacenamiento sobre la aceptación sensorial del queso Coalho obtenido a partir de leche de vacas Guzerat, Gyr y Sindi. Se seleccionaron veinte (20) vacas de razas cebú y se obtuvieron sus valores de frecuencia del polimorfismo genético de la kappa-caseína. La leche se sometió a un análisis de grasa, proteína, lactosa, sólidos no grasos y sólidos totales, conductividad eléctrica y cuenta de células somáticas. Los quesos se sometieron a análisis de grasa, proteína, sólidos totales, pH, humedad y rendimiento (g ST/L). Se evaluaron los atributos apariencia, aroma, textura y sabor en los días 1, 25 y 46 de almacenamiento. La frecuencia total fue de 0.70 para el genotipo AA y 0.30 para el genotipo AB. No hubo diferencias significativas en la composición de la leche entre las razas estudiadas. Sin embargo, hubo diferencias en la composición fisicoquímica (exceptuando la proteína) y el rendimiento de los quesos; pero todas las razas mostraron un rendimiento real similar. El periodo de almacenamiento tuvo efectos observables sobre los atributos sensoriales de los quesos en las diferentes razas, con la excepción de su apariencia. La leche de las razas Guzerat, Gyr y Sindi constituye una excelente materia prima para la producción de cuajada y garantiza una aceptación sensorial satisfactoria del producto a los días 1, 25 y 46 de almacenamiento.