Effects of different molecular weight cut-off membranes and concentration factors on anthocyanin and ascorbic acid levels of blood orange juice

In this research, effects of ultrafiltration and concentration on some chemical properties of Moro blood oranges which are rich in ascorbic acid and anthocyanin contents and have high cultivation potential especially Mediterranean region of Turkey. For this aim, juice of blood orange fruits, taken from BATEM citrus orchard, were obtained at the pilot establishment of Institute and then ultrafiltration process were carried out using three different molecular weight cut-off membranes as 100 kDa, 50 kDa and 30 kDa. Three different clear blood orange juices, produced through ultrafiltration, were concentrated up to different (approximately 45, 55 and 65?Bx) concentrate degrees. Important quality parameters were analyzed at the clear blood orange juices and concentrates.Total anthocyanin, L-ascorbic acid and total phenolic contents of Moro blood orange at the harvesting time, were found as 174.30 mg cyn-3-glu/L, 47.89 mg/100 mL and 1230.02 mg GAE/L respectively. After ultrafiltration; clear blood orange juices were produced but total anthocyanin, L-ascorbic acid and total phenolic contents were significantly affected through ultrafiltration. Although total anthocyanin and total phenolic contents were affected depending on the membrane cut-off degrees, L-ascorbic acid concentrations were not affected significantly from different membrane cut-off degrees. For the ultrafiltration of blood orange juice, the most suitable membrane cut-off degree was found as 100 kDa; total anthocyanin, L-ascorbic acid and total phenolic contents of permeate were found as 150.63 mg cyn-3-glu/L, 39.97 mg/100 mL and 1135.17 mg GAE/L respectively. The turbidity level of this clear blood orange juice was found as 0.084 NTU. In color values; after ultrafiltration the level of a* value, which is characteristic color of blood orange juice, was increased.After ultrafiltration, permeates were concentrated up to three different brix values approximately 45, 55 and 65 ? Bx. During concentration, the level of anthocyanin and L ascorbic acid were decreased. Reaction kinetics, (k value) and half-life times (t1/2) were calculated using changes in anthocyanin and L-ascorbic acid content depending on the concentration degrees. After concentration at 50 ? C and 160 mbar pressure, the calculated k and t1/2 values of clear blood orange juice produced from 100 kDa membrane were -1.702x10 3 (min-1) and 6.788 (h) for total anthocyanin and -1.873x10-3 (min-1) and 6.165 (h) for L ascorbic acid degradations.