FORMATION OF MAIZE STARCH GELS SELECTIVELY REGULATED BY THE ADDITION OF HYDROCOLLOIDS

Native maize starches containing amylose are used for manufacturing ge ls in food technology at concentrations of about 7%. Depending on the pasting conditions chosen, several hours may be required for the final consistency to be attained. For this reason the influence of hydrocol loids was investigated with economic factors dictating an effective co ncentration of approximately 5% in terms of the pure starch. The gelat ion process was monitored quantitatively by means of rheomechanical os cillation measurements in the linear viscoelastic range. The substance s investigated were polysaccharides with chemically similar structures and classified as safe under foodstuff regulations: guar gum, locust bean gum, x-carrageenan, I-carrageenan, xanthan and carboxymethylcellu lose (CMC). The gelation process can be significantly accelerated by a range of hydrocolloids, with the effect decreasing as follows: CMC > locust bean gum > guar gum > x-carrageenan > xanthan. The mixtures ach ieved between 45% and 80% of the final gelation stability of pure star ch of 100Pa. The gelation process is clearly retarded by the hydrocoll oid I-carrageenan. With the aid of the theological data it is possible to correlate the influence of the hydrocolloids on the process of sel f-aggregation and also on the resulting viscoelastic properties of the mixed gels with one another. In terms of a molecular interpretation i t is possible to distinguish between exclusion effects and specific in teractions in the functioning of the hydrocolloids.