On heating, egg white proteins unfold, aggregate through intermolecular interactions of non-covalent and covalent bonds, and form networks to gel. Since the physical properties of egg white gel have a great influence on the texture of foods that use egg white, the control techniques and mechanisms have been extensively studied. In addition to conventionally known hydrophobic interactions and disulfide bonds, lanthionine and lysinoalanine bonds are deeply involved in the heat gelation of egg white. Recently, it was revealed that the covalent bonds are also involved in the formation of soluble aggregates on dry heat treatment of dried egg white. Controlling the formation of soluble egg white protein aggregates is considered a key factor in controlling the heat-induced gelation of egg whites. The aggregation and gelation properties have been studied using various methods, such as the Maillard reaction and electrochemical reaction.

It has been reported that patients with egg allergy can ingest baked eggs without the induction of allergy symptoms. Ovomucoid (OM) is a soluble protein that is resistant to heat; however, OM in baked eggs becomes insoluble. The aim of this study was to analyze the digestibility of OM and its properties (including solubility) to clarify the mechanism by which changes in its properties remove its capacity to induce allergic symptoms. We prepared purified OM, heated OM, non-baked OM, and baked OM and digested them using pepsin, trypsin, and chymotrypsin. We analyzed the digested samples using the Lowry method, SDS-polyacrylamide gel electrophoresis (SDS-PAGE), and immunoblotting. The soluble protein concentrations of purified, heated, and non-baked OM remained unchanged following digestion. The soluble protein concentration in the supernatant of the digested, baked OM was low; however, in pepsin and chymotrypsin digestion, the soluble protein concentration increased during digestion. The immunoblotting results showed that the protein bands detected in the digested supernatant of baked OM were thinner than those of purified, heated, and non-baked OM, even though the protein concentrations were the same. Furthermore, intact OM was detected in the precipitate of baked OM. In trypsin digestion, little change was observed after digestion in either sample. This study suggests that baked OM may have lower antibody binding capacity than other samples, and intact OM remains in the precipitate, which may affect allergy symptom induction.

In this study, it became possible to make barley flour-blended bread having the same breadmaking quality as wheat bread, even when the barley flour content was increased from 20 % to 30 %. If the proportion of barley flour is increased in barley flour-blended bread, the expansion properties and palatability of the resulting bread decrease. The expansion properties of barley flour-blended bread are affected by the hard and thick endosperm cell walls, which are formed by dietary fiber. Since the fragments and particles of the endosperm cell walls generated by milling (crushing) were thought to inhibit the extension of the continuous phase of gluten in the dough, a dietary fiber-degrading enzyme was added for the purpose of further crushing and refining them. However, the addition of the enzyme was expected to decrease dietary fiber, especially β-glucan. A new enzyme addition method was examined that aims both to improve the expansion properties of barley flour-blended bread and to suppress the decrease in dietary fiber, and the optimal conditions for achieving these aims were evaluated. After adding the enzyme, the expansion rate of the barley flour-blended bread improved by 10% on average, and the decrease in total dietary fiber content was limited to approximately 20 %.