A study on the relation between anthocyanin content and product quality: shalgam as a model beverage

The anthocyanin content and the amount of lactic and acetic acids present in commercial shalgam samples randomly collected from domestic markets were determined both by high-performance liquid chromatography (HPLC) and spectral measurements. Shalgam samples produced under laboratory conditions were termed as the control group (Group I). The commercial samples were divided into three groups based on their production date: samples stored for 6-9 months as Group II; samples stored for 9-12 months as Group III; and samples stored longer than 12 months as Group IV. The HPLC chromatograms indicated that black carrot was the only source of anthocyanin present in the samples. The acylated to nonacylated anthocyanin ratio increased significantly in Group IV samples, whereas there were no significant differences among the Groups II, III and control (P < 0.05). The % polymeric color negatively correlated to the total anthocyanin content was significantly higher in Group IV samples (P < 0.05). The presence of high acetic acid content might be an indication of added pickle juice to the shalgam samples. The variance of the level of lactic acid found in commercial samples shows up as a problem of incidental enrichment of the lactic acid bacteria. Anthocyanin profiles of food materials are unique. Therefore, the anthocyanin profile in a commercial beverage can be used to determine whether there is an adulteration or not. The total anthocyanin content and the ratio of acylated to nonacylated anthocyanins, together with the degree of polymerization and browning index, serve as indicators of the time-temperature history of the product. Applying first-order degradation kinetics to the anthocyanin under question the initial hypothetical amounts of the juice bearing that anthocyanin can be evaluated. In the specific beverage investigated, shalgam, the level of lactic acid refers to the amount of bulgur used for fermentation. The amount of acetic acid and its negative correlation with the total anthocyanin content can be used as an indicator of adulteration with pickle juice.