Color stability of strawberry jam fortified by purple carrot puree

The discoloration of strawberry products due to the rapid degradation of pigments is considered as one of the most quality defects that affect their acceptance. Therefore, in the present study, the objective was to investigate the possibility to improve the color stability of strawberry jam by using purple carrot puree. The obtained results declared that purple carrot puree characterized by high content of anthocyanins and total phenols compared to strawberry puree. Furthermore, the contents of individual anthocyanins were analyzed by HPLC. The highly stable acylated anthocyanins pigments represented 66.64% of total anthocyanins in purple carrot compared to 20.6 % from strawberry. Cyandin-3-xylosyl-glucosyl-galactoside acylated with Ferulic acid was the predominant anthocyanin in purple carrot while Pelargonidin 3-glcosside was the major component in strawberry. Purple carrot puree was adding by 15, 20 and 30% to strawberry puree during jam processing. The jams were monitored over a period of 6 month of storage under normal conditions of light exposure and room temperature. The results revealed that pH value, viscosity, total anthocynin and total phenol contents were increased gradually by increasing the amount of purple carrot and markedly decreased the degradation of anthocyanin during storage period by 53.2, 52.9, 18.0 and 7.3%in control,15, 20 and 30% samples respectively. Furthermore, the color of jams were controlled during the storage period. L∗, a∗ , b∗, hue o and chroma values showed that the color of strawberry jams containing purple carrot was improved and showed stability. The results of sensory evaluation revealed that the jam of 20% purple carrot treatment obtained the highest overall acceptability score at the end of storage period. Finally, from all results obtained, it can be concluded that the addition of purple carrot up to 20% during strawberry jam processing maintained the color of jam without any effect on their acceptance.