Effect of continuous flow HTST treatments on donkey milk nutritional quality

Nutritional quality of raw donkey milk (DM) may be impaired during sanitization with the current batch holder pasteurization systems (62.5 °C for 30 min). In this paper, we present the preliminary results concerning the effects of high temperature for short time (HTST) protocols using an innovative in continuous low flow rate pasteurization plant (60 dm3/h) on B-vitamins group, antioxidant capacity, lysozyme and β-lactoglobulin in DM. Lysozyme, β-lactoglobulin and antioxidant power decreased after the thermal treatments, with characteristics depending on the extent of the heat treatment. The lysozyme content was substantially reduced between 20 and 60%, while the degradation of β-lactoglobulin was lower (2–22%). No vitamin B1 and B12 were found in raw milk, whereas were detected vitamin B2 (0.17 μmol/L), nicotinic acid (13.28 μmol/L), B6 (2.06 μmol/L) and B9 (0.75 μmol/L). The heat treatments carried out with the innovative plant ensured vitamin retention, as no significant differences were found against the raw milk (p > 0.05). The preliminary results from this study represent a guidance to the establishment of DM pasteurization standards parameters with the perspective to improve DM nutritional quality.