Effect of carrot juice and stabilizer on the physicochemical and microbiological properties of yoghurt

Abstract

Yoghurt fortification with fruits and vegetables has high potential to improve the nutrients and health promoting effects of the yoghurt. The effects of carrot juice (0, 10, 15 and 20%) and gelatin stabilizer (0.5,0.6 and 0.7%) (w/w, base milk) addition on the properties of 12 yoghurt samples in a 3 4 factorial arrangement were investigated. Addition of carrot juice increased pH and syneresis significantly, but decreased titratable acidity (TA) and total viable counts (TVC). The TA and TVC were higher than min-imum recommended of 0.6% lactic acid and 6 log10CFU g 1, respectively for yoghurt. Coliform, yeast and mold counts were<10 CFU g 1. Syneresis decreased with stabilizer addition (p<0.01). With 10 to 20percent carrot juice addition, the total carotenoid content (mg/kg) increased (6.73 and 10.26, respectively) compared to control (3.05) (p<0.05). However, the effects of carrot juice and stabilizer additions on total phenolic contents and antioxidant ferric reducing power were insignificant (p>0.05). The re-sults showed that yoghurt with suppressed syneresis and improved nutritional and total carotenoids contents can be processed from 10 to 15 percent carrot juice and 0.7 percent stabilizer additions.