engleski

Influence of storage on rheological properties of raspberry puree with addition of sugars, modified starches and hydrocolloids

The rheological properties of foods are important quality factor. Chemical compositions, technological process of production and different food additives have influence on rheological properties of food. Starch is used as additive in many foods for improving of rheological properties and gelling. Natural starch is not suitable for application in many foods because of retrogradation, syneresis and low stability. Because of above mentioned, modified starches are in use. For consistency and stability increasing and for gelling in food production, hydrocolloids are used too. This paper deals with an influence of storage on rheological properties of raspberry puree with sugars, modified starches and hydrocolloids addition. The puree was made by mashing of raspberry and with addition of sucrose (27 %) and combination of sucrose (17 %) and fructose (10 %). Modified starches, textra (1%) and frigex (1%), hydrocolloids, karaya (0, 05 %) and guar (0, 05 %) were added in mentioned purees. All of purees were put in the bottle and pasteurised on 85°C within 15 minutes. Pasteurised purees were stored at room temperature and at 4°C.Rheological properties (shear stress and shear rate at different temperatures) were measured by rotational viscosimeter, model DV – III + Digital Rheometer, Brookfield Engineering Laboratories. Results showed that examined additives had a different impact on rheological properties of raspberry puree. The maximal consistency had the puree with addition of frigex. During storage at room temperature significant decrease of consistency at all additives except frigex additive occurred. The storage at 4°C didn't have significant effect on consistency decrease.

raspberry puree; rheological properties; modified starches; hydrocolloids

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