TY - JOUR TI - Development of zein-based ice nucleator films for frozen food applications DO - https://doi.org/doi:10.7282/T3057DPD PY - 2012 AB - This research aimed at developing zein-based ice nucleation films for the applications of frozen foods. Acetic acid was chosen as the solvent to cast zein films with flawless surface. Tributyl citrate (TBC) was mixed into zein films to various proportions and 10% TBC was most effective on improving mechanical properties resulting in 2.3-fold more flexibility and 5.8-fold more toughness compared to unplasticized zein films. But incorporation of 20% TBC significantly decreased the water absorption by 19% compared to 10% TBC. Thus, zein films with 20% TBC with good flexibility and water resistance was used in following experiments. The activity of ECINs was stable at pH between 4.0 and 9.0 and ionic strength between 0.01 M and 0.10 M. In the development of INFs, the optimum adsorption of ECINs on zein films surface occurred through layer-by-layer method at pH 7.0 and ionic strength of 0.05 M on UV/ozone-treated zein. A novel method was developed to quantify the activity of INFs, which revealed that the highest activity of zein-based INFs reached 175 units/mm2. The zein-based ice nucleation films (INFs) were used to wrap frozen bread dough during five freeze/thaw cycles. The high-activity INF was as effective as blending ECINs in improving the yeast survival by 40%, and consequently increased the specific volume of bread loaf by 25%. Furthermore, high-activity INFs prevented the dehydration of frozen dough and thus significantly reduced the crumb hardness by 36% and increased the crumb springiness by 1.25 times. On energy saving, zein-based INFs were less potential than blended ECINs. INFs only reduced the time of freezing by 6% compared to the 20% by blended ECINs. However, the total amount of ECINs used on wrapping a piece of dough was only about 1/200 of the amount through blending. In addition, ECINs immobilized on the zein films showed desirable stability to sustain at least fifteen repetitive uses on freezing water. KW - Food Science KW - Frozen foods--Packaging KW - Ice nuclei LA - eng ER -