The Deterioration Mechanism Of Gelling Ability Of Whole Egg Liquid And Powder During Storage And Its Control Approach

The gel property is one of function of the liquid whole egg (LWE)/whole egg powder(WEP). Main reason of gel property decline of LWE/WEP during storage was investigatedand tried to find a way to improve its gel ability. This study provide theoretical basis of deepprocessing of egg that can manufacture new instant liquid egg of egg powder.Different processes and food additives have much effect on the gel properties of LWE.This paper discusses the influence of homogeneous conditions and heat treatment intensity onthe gel properties of the LWE. Before heat treatment, using30MPa pressure to homogeneousLWE will get the highest gel ability. Using heat treatment intensity65°C3min, can ensurethat the whole egg has a shelf life of more than two weeks, at the same time, it can make LWEgot best stability of gel properties during storage. At pH8.0, LWE/WEP get best gel strengthand water holding capacity. The addition of NaCl, lecithin and glutathione can increase thegel strength of LWE effectively.Due to the significantly decrease of LWE/WEP during storage, this study investigate thechanges of sulfhydryl content, surface hydrophobicity and particle size of protein inLWE/WEP to figure out gel property stability of LWE/WEP. The protein hydrophobicityresult showed that hydrophobicity increase marked during storage. Compare to0d, proteinhydrophobicity increase about80%in14d, this lead to aggregation between protein.Partialsize and turbidity of protein increase marked, that prove protein aggregation happened.Sulfhydryl group decrease much during storage. Compare to0d, protein total sulfhydryl groupdecreased about30%in14d. SDS-PAGE showed that protein pattern did not change duringstorage. This means that there were no other acting force except disulfide bond andhydrophobic aggregation. All the results suggested that decreasing of gelling ability of liquidwhole egg may due to the disorderly gathering of protein, and decreased disulfide groupformed during storage. Both of these reasons may lead to the nonuniform gelling and decreaseof the strength and water-holding capacity of whole egg gel during storage.To solve problem that protein sulfhydryl group decline, this study investigate the effect ofpH adjust, surfactant and different antioxidant agent on gel property of LWE/WEP. Ascorbicacid and glutathione’s reduction effect can avoid protein sulfhydryl group decline duringstorage effectively, therefore increasing the gel strength of LWE/WEP during storage.0.01%ascorbic acid (w/w) providing a reducing environment, that can alleviate the gel strengthdegradation of LWE. With the increase of the quantity of glutathione, gel strength ofLWE/WEP increasing. Gel strength was increased nearly100%in the presence of0.07% (w/w) glutathione. Glutathione can effectively maintain the gel property stability ofLWE/WPE during storage.