Effect of wheat flour particle size on the quality deterioration of quick-frozen dumpling wrappers during freeze-thawed cycles.

To reveal the effect of wheat flour particle size on the quality deterioration of quick-frozen dumpling wrappers (QFDW) during freeze-thawed (F/T) cycles, the components and physicochemical properties of wheat flours with five different particle sizes were determined and compared, along with the changes in texture and sensory properties, water status, and microstructure of QFDW during F/T cycles. Results showed that as particle size decreased, the damaged starch content and B-type starch content increased, the water absorption increased, and the gluten strength decreased. Furthermore, F/T cycles negatively impacted the quality of QFDW, evidenced by decreased texture properties and sensory evaluation score, water redistribution, higher freezable water content, and disruption of gluten network. Notably, QFDW made from larger particle size wheat flours required the shortest duration when traversing the maximum ice crystal formation zone. The QFDW made from larger particle size wheat flours formed a more stable starch-gluten matrix, which resisted the damage caused by ice recrystallization, demonstrating better water binding capacity and F/T resistance. The results may provide theoretical guidance for the study of QFDW quality and the moderate processing of wheat flour in actual production.

Structural and physicochemical characteristics of wheat starch as influenced by freeze-thawed cycles and antifreeze protein from Sabina chinensis (Linn.) Ant. cv. Kaizuca leaves.

The effects of freeze-thawed cycles (FTs) and a new antifreeze protein from Sabina chinensis (Linn.) Ant. cv. Kaizuca leaves (ScAFP) on the structure and physicochemical characteristics of wheat starch were studied. The mechanical breaking exerted by ice crystals on starch granules during FTs gradually deepened, sequentially squeezing the surface (2-6 FTs), amorphous region (8 FTs) and crystalline region (10 FTs) of starch granules. These changes led to reduced thermal stability, increased retrogradation tendency, and weakened gel network structure. The addition of ScAFP retarded the damage of ice crystals on starch granule structure and crystal structure during FTs, and significantly reduced the retrogradation tendency. Compared with native starch, the hardness of freeze-thawed starch without and with added ScAFP after 10 FTs decreased by 17.85% and 9.22%, respectively, indicating ScAFP improved the gel texture properties of freeze-thawed starch. This study provides new strategies for improving the quality of frozen starch-based foods.