Abstract:

In the present study, proteins were extracted from the young stems with leaves of Zhaodong alfalfa with
phosphate buffer solution. Furthermore, the optimal extraction conditions for alfalfa proteins were determined by singlefactor
experiment and response surface methodology. The results revealed that when the extraction was carried out by 2 h
stirring of the 80-mesh raw material powder suspended in 63 mmol/L phosphate buffer solution at pH 7.7 with a solid/liquid
ratio of 1:20, the yield of alfalfa proteins was 37.77%. The observed ice crystal morphology suggested that the ice crystals
of the purified alfalfa proteins were small in size, increased in number and varied morphologically, indicating that the alfalfa
proteins are able to significantly inhibit the growth and modify the conformations of ice crystals. These results demonstrate
that the alfalfa proteins, which possess excellent antifreeze activity, are ice structuring proteins. In addition, we characterized
the functional role of these alfalfa proteins in practical application by application in frozen dough. The results of texture
properties demonstrated that the frozen dough mix had a soft and delicate texture, and increased elasticity, resilience and
cohesion, but reduced chewiness.

Key words: alfalfa, ice structuring protein, ice crystal, frozen dough