Use of date (Phoenix dactylifera L.) blanching water for reconstituting milk powder: Yogurt manufacture

The processing of dates yields high volumes of blanching water. The use of such blanching water for reconstituting skim milk powder to produce low fat yogurt was studied. Physicochemical properties and antioxidant activity of two date cultivars (Medjoul and Confitera) blanching water were determined. Quality characteristics of yogurts (control, Medjoul and Confitera) were evaluated during 28 days of refrigerated storage. Results showed that Confitera blanching water is considered a good source of natural antioxidants and organic acids, and has a promising future as a functional ingredient, whereas Medjoul blanching water had a high content of sugars. Regarding yogurt characteristics: Confitera yogurts presented highest populations of lactic acid bacteria, and gave soft gels of weak structure, Medjoul yogurts presented higher firmness and sensory scores than Confitera.

► Water used for blanching dates contains soluble solids and organic acids that stimulate yogurt fermentation process.
► Confitera dates blanching water is a good source of bioactive compounds with antioxidant properties, whereas Medjoul dates blanching water provides sweetness and date taste.
► Dates blanching water provides brownish color to yogurts.
► Medjoul blanching water provides yogurts with harder texture than Confitera and control yogurts.
► Addition of Confitera dates blanching water reduces yogurt consistency.
► Reconstituting milk powder with dates blanching water provides yogurts with high sensory scores.