Clarification of Adhesion Mechanisms of Soils onto the Equipment Wall Surfaces and Its Desorption in Food Manufacturing Process

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In this study, we focussed to the following three subjects, i.e., 1) clarification of adsorption characteristics of proteins, peptides, and amino acids, 2) identification of peptide regions in protein molecules that interact with solid surfaces, and 3) cleaning behaviors of the surfaces fouled with proteins using proteolytic enzymes and hydroxyl radicals generated by combined hydrogen peroxide and ultraviolet rays. Adsorption behaviors of β-lactoglobulin, bovine serum albumin, and gelatin onto the stainless steel surface were investigated under different conditions. With increasing the temperature, the adsorbed amount of β-lactoglobulin and bovine serum albumin were increased to form disulfide linkages, whereas that of gelatin decreased. Furthermore, adsorption behaviors of amino acids and peptides were examined in detail, which showed the importance of acidic amino acids in the adsorption behaviors. The adsorption behaviors of peptides obtained by digestion of β-lactoglobulin with trypsin were investigated. It was found that a peptide fragment (^<125>Thr-Pro-Glu-Val-Asp-Asp-Glu-Ala-Leu-Glu-Lys^<136>) showed an irreversible adsorption behavior and this region was thought to be one of the interaction sites in the protein. FT-IR analyses revealed that the acidic amino acids were dissociated on adsorption onto the stainless steel surface. Cleaning behaviors of the stainless steel particles fouled with proteins by enzyme cleaning (proteases) and hydroxyl radical cleaning were carried out under various conditions to compare their performances with caustic cleaning and their cleaning mechanisms were studied.