Effect of some hydrocolloids on the consistency and serum separation of different formulated ketchups

ABSTRACT EFFECT OF SOME HYDROCOLLOIDS ON THE CONSISTENCY AND SERUM SEPARATION OF DIFFERENT FORMULATED KETCHUPS Hilal ŞAHİN M. Sc in Food Engineering Adviser. Assoc Prof. Dr. Feramuz ÖZDEMİR July, 2003, 115 pages In this research, the effect of five different hydrocolloids viz. tragacanth gum, guar gum, carboxymethylcellulose, xanthan gum and locust bean gum, added to three different formulated ketchups at three doses (0, 0.5, and 1%), on the consistency and serum separation of produced tomato ketchups was aimed to determine. For this purpose, canned cold break tomato paste was diluted as having a total soluble solids (TSS) content of 7.5, 10, and 12.5 %, respectively and obtained concentrates were processed to ketchups by addition of other ingredients ascertained by formulation receipts. Five different hydrocolloids were added to each ketchup formulation at levels of 0, 0.5, and 1%, respectively and the effect of these on the the consistency and serum separation of tomato ketchups was investigated. According to the results, all hydrocolloids increased consistency of tomato ketchups, however, guar gum and locust bean gum caused maximum increase followed by xanthan gum, tragacanth gum and carboxymethylcellutose. Both ketchup formulations and addition levels of gums were found to be effective on the consistency of produced ketchup samples and maximum increase in consistency indexes were obtained by processing diluted paste of having a TSS content of 12.5 % and addition gums at levels of 1%. Furthermore, flow value at bostwick consistometer and serum separation (%), obtained by following two different methods, were also observed and both serum mseparation and flow value decreased with the addition of all the hydrocolloMs and increases of gum levels. In addition to these, flow value and serum separation of produced samples were also affected by ketchup formulations and these parameters were found to be lower for ketchup samples, prepared from diluted paste of having a TSS content of 12.5%, than the other formulations. The second part of the research included comparisons of produced ketchup samples, processed from diluted paste of which was having a TSS content of 10% and added with 0.5% level of hydrocolloids, with the three brands of commercial tomato ketchups, from the point of view of some physical and sensory properties. Except CMC, all other hydrocolloid additions to the ketchup samples provided the higher consistency index than that of commercial samples and serum separation levels were found to be higher for the commercial samples. In addition, the ketchups, produced in this study, were found to be having an acceptable sensory properties. According to the results of the study, it was concluded that, in situation which tomato ketchup is being prepared from tomato paste, 0.5 % addition of hydrocolloids was found to be effective for providing optimum consistency and lower serum separation of ketchup samples. KEYWORDS: Tomato ketchup, hydrocolloids, gums, consistency, viscosity, serum separation COMMITTEE: Assoc. Prof. Dr. Feramuz ÖZDEMÎR (Adviser) Prof Dr. Muharrem CERTEL Prof. Dr. Hasan FENERCÎO?LU IV