Chemical and microbial evaluation of Egyptian dried egg white prepared by different techniques

Abstract

Egg white was dehydrated (pan drying, spray drying) without and with glucose removal (using bacteria, yeast and enzyme). Although, moisture, protein and ether extract percentage in spray dried samples were, in general, in the same range as the imported Swiss made spray dried sample (as standard), yet the least moisture percentage was found in samples in which sugar was removed by yeast. The standard sample had the best solubility (99.79%). followed by the spray dried sample desugarized by yeast (99.677;). Samples in which Stvepfococcus lacfis was used gave the highest percentage of insoluble matter (4.z4X). Pan dried and spray dried samples were similar in solubility.The total microbial counts were found to decrease in egg white after drying (max. 4.9 x 10 org.in prepared samples, zero in the standard). Salmonella was absent in all dried samples. There are variations in the type of protein fractions of liq'uid egg white when the enzyme treatment or controlled bacterial fermentation were used. When yeast fermentation was used a decrease in some protein fractions was noticed in comparison with the nondesugarized sample. The dehydrated egg ,white proteins indicate that there was no difference between the different techniques applied for glucose removal, between drying methods and between prepared samples and imported one; 5 fractions were obtained in each sample.-411 over the world, the demand for dehydrated egg white began to increase for many industries such as an adhesive for cork in bottles capsules in carbonated beverage plants, for coating of roasted coffee and for use in cake mixes.Dehydration of egg white is carried out mainly by two ways, pan drying or drum drying and spray drying processes. The drying process should permit the retention of certain valuable properties of the fresh egg white such as solubility of the protein, aerating capacity, binding power and palatability.Dehydration 758DARWISH/SHEHAB/SADEK countries. They succeeded in depleting glucose in Egyptian egg white by using a crude enzyme complex which contained glucose oxidase and catalase and was prepared from penicillium notaturn. DARWISH et al.[6] studied the different methods that could be applied for depleting glucose in Egyptian egg white before dehydration. The present study was done to find out the best method that could be applied for preparing dried egg white in Egypt as a new industry. Egg .white was dehydrated with and without glucose removal.Glucose removal was carried out using bacteria, yeast and enzyme. Both pan drying and spray drying methods were used.Evaluation of the final dried products was done by determining both chemical and microbial composition of prepared dried products in comparison with an imported dried sample.Electrophoretic analysis of protein was carried out on liquid egg white before and after glucose removal and after dehydration. Materials and methodsChicken eggs were obtained from the poultry farm of the Animal Husbandry Dept. Ministry of Agriculture, Cairo, Egypt.The eggs were first washed, then examined b...

Statistical optimization of desugarization process parameters of liquid whole egg using response surface methodology

“…The selection of the fermentation time, temperature, pH and yeast concentration was based on some previous works of various researchers, while response variable was reducing sugar concentration (g/100 g). The experimental ranges for the independent variables were selected as concentration of yeast in range of 0.5e2.3 (g/L), temperature in range of 25e35 C, fermentation time in range of 1e12 h and pH in range of 6.0e7.5 with respect to the reported literature (Darwish, Shehab, & Sadek, 2006;D'Souza & Godbole, 1989;Stadelman & Cotterill, 1995, pp.322e328). The range and the levels of the experiments variables used in the coded and uncoded form in this study are given in Table 1.…”