A comparative study has explored the freeze-thaw stability of native and modified starches - important because of the increasing interest in the use of 'clean label' starches in products. Starch is used to control product properties such as mouthfeel, processing characteristics and product stability. In frozen and cold-stored products the stability of the starch is important in reducing problems such as water separation (syneresis).

The aim of the study was to compare the performance of 'clean label' (physically modified and native) and chemically modified starches, designed as cook-up starches with freeze-thaw stability. Freeze-thaw trials were performed on a low-pH tomato sauce, a high-sugar toffee sauce and a high-fat cheese sauce. With controlled freezing and little temperature fluctuation, physically modified waxy maize starch and native waxy rice starch showed acceptable stability, but during freeze-thaw cycling high-level stability was only achieved with chemically modified waxy maize starch. All the starches were unstable to some extent in the high acid tomato sauce.

The work demonstrates the importance of carefully controlled trials to establish the effects of changes in the starch on product performance before formulation or process changes are made.

*R&D Report 248 available to members from Carol Newman +44(0)1386 842048 pubs@campden.co.uk