The objective of the present study was to utilize whey and permeate as the by-products of the cheese industry after mixing with kumquat purée and/or paste for producing functional beverages. Physical, chemical, physicochemical,
microbiological and sensory properties of kumquat fruit and its purée and paste were studied. The results indicated that kumquat purée and paste are good sources of β-carotene, vitamin C, minerals such as calcium, potassium and magnesium, total phenolic acids and flavonoids. In addition, they have high antioxidant capacity. Physicochemical,
microbiological and sensory properties of the prepared functional beverages during cold storage periods were determined. The obtained results indicated that ascorbic acid and β-carotene of all beverages were higher than those of whey and permeate only, with a high level of total phenols, flavonoid content and antioxidant activity. Generally, sensory evaluation of the prepared beverages showed that the addition of purée and paste of kumquat fruit to whey and permeate increased the overall acceptability of these beverages. Total count was in permissible limit while the coliform
and moulds & yeasts counts were not detected in all beverages during storage at 4±1°C for 28 days. Beverages containing purée and paste of kumquat fruit could be recommended as new acceptable functional products.