46-1 |
|
A. REGAND1, H. D. Goff, and E. Verespej. (1) Department of Food Science, University of Guelph, Guelph, ON N1G 2W1, Canada Ice recrystallization is a major concern in the distribution chain and storage of frozen foods. Ice structuring proteins (ISPs) act as ice modulators in over-wintering cereal crops and therefore represent a possible alternative to reduce ice crystal growth in these products. Our objective was to study the potential application of ISPs from a cold-acclimated winter wheat grass extract (AWWE) in ice cream. The effects of pasteurizing the AWWE and removing the stabilizer were also evaluated. Conventional ice cream mixes were prepared and 0, 0.0025 and 0.00375% total protein from AWWE were added. Mixes were pasteurized, homogenized and frozen in a scraped surface freezer. Additional mixes were prepared when AWWE (0.00375%) was added after pasteurization and in others the stabilizer was removed from the formulations. Samples were stored at -35°C, -18°C and heat shocked for one month. Ice crystal growth (ICG) was calculated from image analysis of images acquired using a cold stage and a light microscope. ISP activity was defined as the % ICG inhibition compared to 0% AWWE. Ice recrystallization rates were significantly reduced by 46% with the addition of AWWE in samples that were heat shocked. Adding the AWWE after pasteurization, reduced its activity to 30%, probably due to an heterogeneous distribution of the ISPs in the mix. With the total removal of stabilizer, ISPs were not significantly active in retarding recrystallization. For samples stored at -18°C the differences in ICG were not significant, however the same trends were observed as for the heat shocked samples. The efficiency of ISPs from AWWE in controlling ice crystal growth in ice cream has been demonstrated. A synergistic effect between ISP and stabilizer is suggested. The ISP resistance to pasteurization represents an advantage in their industrial application.
Session 46, Dairy Foods: General
|