Influence of Freeze-Drying on the Physicochemical Composition, Fatty Acid Profile, and Antioxidant Activity of Donkey Colostrum

The present study provides comparative data on the physicochemical characteristics, antioxidant activity, and fatty acid composition of native and freeze-dried donkey colostrum. The results demonstrated that freezing, freeze-drying, and subsequent rehydration did not induce substantial changes in the overall physicochemical characteristics and fatty acid profile. The physicochemical characteristics and fatty acid profiles of the two matrices exhibited a high degree of similarity. Differences in the content of individual fatty acids between native and freeze-dried colostrum were below 30.0 g kg⁻¹ of fat, while differences in the respective fatty acid groups and subgroups did not exceed 50.0 g kg⁻¹ of fat. Elevated levels of polyunsaturated fatty acids (270.3 and 238.4 g kg⁻¹ of fat), omega-3 fatty acids (184.6 and 162.0 g kg⁻¹ of fat), and α-linolenic acid (183.9 and 159.8 g kg⁻¹ of fat) were observed compared with the reference values reported in the literature for raw donkey colostrum. The omega-6/omega-3 ratio in the investigated samples was considerably lower than previously reported, indicating their high biological and nutritional value. Antioxidant activity, determined by the DPPH assay, showed comparable values for native (13.4 %) and rehydrated colostrum (14.5 %), while a similar trend was observed using the ABTS assay (79.9 % and 78.8 %, respectively). To the best of our knowledge, limited information is currently available on the physicochemical characteristics, fatty acid profile, and antioxidant activity of freeze-dried and subsequently rehydrated donkey colostrum.