Characterization of extra-hard cheese produced from donkeys’ and caprine milk mixture

Abstract

Cheese cannot be produced solely from equine or donkeys’ milk, because of the unique physico-chemical properties of these milks. The purpose of this study was to characterize a novel dairy product, cheese produced from donkeys’ and caprine milk mixture (60:40% v/v), regarding its chemical, microbiological, textural and sensory properties. Fully ripened cheese was classified as a high-fat, extra-hard cheese, with high sodium (29.97 g.kg−1), magnesium (3.07 g.kg−1) and potassium (4.70 g.kg−1) content. The characterization by lab-on-a-chip electrophoresis revealed lysozyme, α-lactalbumin, immunoglobulins and casein fractions. Palmitic (C16:0) and oleic fatty acids (C18:2 n9-cis) with 25.11 and 24.70%, respectively, were found at the highest concentrations. The medium-chain fatty acids account 18.21% of the total fatty acid content in analysed cheese samples. Escherichia coli, Salmonella spp., Enterobacteriaceae, coagulase-positive staphylococci, Listeria monocytogenes, Bacillus cereus, Clostridium perfringens as well as moulds were under the limit of detection in all analysed samples. After 6 months of cheese ripening (0.94 aw, pH 4.71), total bacterial count, the counts of lactic acid bacteria and yeasts were 6.34 ± 0.03, 4.80 ± 0.10 and 5.81 ± 0.11 log CFU.g−1, respectively. The texture of mature cheese was moderately hard and crumbly. The cheese was described as very salty with strong pronounced creamy, fatty and acidic taste. The characterized donkey/caprine cheese could position this type of cheese as a high-quality functional product, thus having a potential impact on the market.