Nutritional characterization of a fermented beverage from donkey milk

The present work is part of the Tool4MEDLife project (PRIMA program), which aims to in-crease awareness about the Mediterranean diet thanks to the production of innovative foods and educational toolkits. Donkey milk, due to its potential hypoallergenic properties, has been sug-gested as a good alternative for feeding young children affected by cow milk protein allergy (CMPA) when it is not possible to breastfeed. Furthermore, thanks to the presence of nutraceu-tical molecules with antioxidant, anti inflammatory, antimicrobial, antiviral, and antitumor activities, donkey milk is interesting also for elderly people. Considering the high quality char-acteristics associated with fermented milk, the aim of this work was the production of ferment-ed donkey milk by selected Lactic Acid Bacteria (LAB) able to synthesize folates (vitamin B9). The final product was also fortified with vitamin D3 and calcium. The levels of folates of natu-ral origin represent an optimal alternative to synthetic folate-fortified products, which have limited bioavailability, and possibly lead to the accumulation of unmetabolized folic acid. Five fresh pasteurized donkey milk samples, added with vitamin D3, calcium carbonate, Streptococ-cus thermophilus, Lactobacillus delbrueckii ssp. bulgaricus and Lactobacillus plantarum IMC 509 (Synbiotec), were fermented at a constant temperature of 38-40°C for 5 hours. Folate con-tent on the final product was determined by RP HPLC (Agilent 1260 Infinity LC system), using a column C18 HiQSil HS, 5 μm, 4.6 mm i.d., 250 mm (Kya Tech Corporation, Tokyo, Japan). The fermentation process led to the production of a fermented beverage with a final pH value of 4.4. The determination of folates by RP HPLC indicated mainly the presence of tetrahydro-folate (5.3 ± 0.081 M) which is a form of folate with high bioavailability. Other water soluble vitamins found in the final fermented donkey milk were vitamin C (110.16 ± 13.5 M), nicotin-ic acid, and nicotinamide (52.7 ± 0.05 M and 7.36 ± 0.15 M respectively), and also vitamin B12 (1.69 ± 0.022 M). Comparing the above results with the water soluble vitamin content of donkey milk present in the literature, it can be noticed that the vitamin content found in the fermented donkey milk beverage is considerably higher. These preliminary results indicated that the LABs used in these experiments are very promising to produce fermented donkey milk with enhanced nutraceutical properties. Research supported by: PRIMA, Partnership for Research and Innovation in the Mediterranean Area supported by the European Union - Section 2, Tool4MEDLife Project - PRIMA22_00088 - CUP: J13C23000150002.