Interpretation of the effects of hydroxypropyl starch and hydroxypropyl distarch phosphate on frozen raw noodles quality during frozen storage: Studies on water state and starch-gluten network properties

Effect of oxidized starch on the storage stability of frozen raw noodles: Water distribution, protein structure, and quality attributes

Freezing is a popular method of food preservation with multiple advantages. However, it may change the internal composition and quality of food. This study aimed to investigate the effect of modified starch on the storage stability of frozen raw noodles (FRNs) under refrigerated storage conditions. Oxidized starch (OS), a modified starch, is widely used in the food industry. In the present study, texture and cooking loss rate analyses showed that the hardness and chewiness of FRNs with added OS increased and the cooking loss rate decreased during the frozen storage process. Low-field nuclear magnetic resonance characterization confirmed that the water-holding capacity of FRNs with OS was enhanced. When 6% OS was added, the maximum freezable water content of FRNs was lower than the minimum freezable water content (51%) of FRNs without OS during freezing. Fourier-transform infrared spectroscopy showed that after the addition of OS, the secondary structures beneficial for structural maintenance were increased, forming a denser protein network and improving the microstructure of FRNs. In summary, the water state, protein structure, and quality characteristics of FRNs were improved by the addition of OS within an appropriate range.

Effects of starch hydration properties on the batter properties and oil absorption of fried crust and battered ham sausages

Water plays an important role in deep-frying. To assess the effects of water on oil absorption by fried crust and battered ham sausages (FCBHSs), we selected four starch types with different hydration properties: tapioca starch (TS), freeze-thawed tapioca starch (FTS), carboxymethyl tapioca starch (CMTS), and carboxymethyl freeze-thawed tapioca starch (CM-FTS). CMTS had the best hydration properties, followed by CM-FTS, FTS, and TS, respectively. CM-FTS with its medium hydration properties strengthened batter properties which reduced FCBHSs oil absorption. Low-field nuclear magnetic resonance analysis revealed that CM-FTS increased the percentages of bound and semi-bound water in the batter, thereby enhancing water retention and delaying water loss during deep-frying. Analyses of protein particle size distribution, zeta potential, disulfide bonding and microstructure revealed that CM-FTS promotes protein aggregation and the formation of a protein network structure, leading to a denser internal structure, which inhibits oil absorption. Additionally, differential scanning calorimetry analysis indicated that CM-FTS enhances the batter's thermal stability of batter, thereby rendering it more resistant to frying. However, the use of CMTS, with its strong hydration properties increased FCBHSs oil absorption. In conclusion, we propose that suitable modification of starch's hydration properties can aid in preparing deep-fried battered food characterized by low oil absorption.