The determination of some physicochemical properties and overall acceptability of functional flavored milk containing pomegranate peel extract and date palm syrup during cold storage

Pomegranate fruits peel is an inedible part obtained during processing of pomegranate juice. Pomegranate peel is a rich source of tannins, flavonoids and other phenolic compounds. The palm syrup has unique odor and taste; it has high potential to be a new sweetener which is natural and chemical-free. In this study, the effect of aqueous extract of pomegranate peel adding at levels 10%, 20%, 30% and palm syrup adding at levels 2%, 4%, 6% on some physicochemical (pH, titratable acidity, total solid and viscosity) and overall acceptability of functional flavored milk was investigated during 21-day cold storage. The milk used for producing functional flavored milk samples was preheated at 50ºC, palm syrup and pomegranate peel extract were added to milk and were mixed for 5 minutes; then, The mix was heated at 75ºC for 15 minutes. After cooling at 25°C, flavored milk samples were hold at 4ºC. Acording to present research, with adding pomegranate peel extract pH, viscosity and total solid decreased (p<0.01); however, titratable acidity increased (p<0.01). Reduction in pomegranate peel extract levels improved overall acceptability of functional flavored milk samples (p<0.01). With adding palm syrup, titratable acidity (p<0.05) and total solid (p<0.01) decreased; however, pH and viscosity increased (p<0.01). With adding different amounts of palm syrup, there was no different in sensory properties of flavored milk samples (p>0.05). In terms of overall acceptability, functional flavored milk sample containing 10% pomegranate peel extract and 4% palm syrup gained the highest score in comparison with the other samples.