A Comparative Study of Different Freezing Methods on Water Distribution, Retrogradation, and Digestion Properties of Liangpi (Starch Gel Food)

Abstract In this work, the effects of refrigerator freezing method (RF), spiral tunnel freezing method (SF), and liquid nitrogen spray freezing method (LF) on water distribution, microstructure, retrogradation, and digestion properties of Liangpi are investigated. Results from SEM and water distribution show the starch gel structure of Liangpi after LF treatment is more continuous, and its A 21 content is higher, which are closer to fresh Liangpi, followed by SF and RF. XRD and FT‐IR data indicate that as the freezing rate increases, the relative crystallinity and R 1047/1022 value of the samples decrease. This is consistent with the data obtained from texture properties. Texture properties of samples treat by LF and SF are closer to fresh Liangpi, especially the hardness index. The in vitro digestibility of Liangpi also shows the same trend. Therefore, the freezing method with a faster rate could inhibit the starch gel retrogradation, improve the texture properties of Liangpi, and guarantee the quality of Liangpi. However, considering the economics of enterprise production, the spiral tunnel freezing method is more suitable for the actual production of frozen Liangpi. The data obtained provide a theoretical guidance for the actual production of frozen Liangpi.