A critical review on surface modifications mitigating dairy fouling

Thermal treatments performed in food processing industries generate fouling. This fouling deposit impairs heat transfer mechanism by creating a thermal resistance, thus leading to regular shutdown of the processes. Therefore, periodic and harsh cleaning-in-place (CIP) procedures are implemented. This CIP involves the use of chemicals and high amounts of water, thus increasing environmental burden. It has been estimated that 80% of production costs are owed to dairy fouling deposit. Since the 1970s, different types of surface modifications have been performed either to prevent fouling deposition (anti-fouling) or to facilitate removal (fouling-release). This review points out the impacts of surface modification on type A dairy fouling and on cleaning behaviors under batch and continuous flow conditions. Both types of anti-fouling and fouling-release coatings are reported as well as the different techniques used to modify stainless steel surface. Finally, methods for testing and characterising the effectiveness of coatings in mitigating dairy fouling are discussed.

Surface characterization of oxidized myofibrils using X-ray photoelectron spectroscopy and scanning electron microscopy

The functional properties of myofibrils depend largely on their surface characteristics. Changes in surface characteristics of myofibrils after chemical oxidation were elucidated using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy. Myofibrils were oxidized by a hydroxyl radical generating system. Lipid oxidation and phospholipid distribution were altered during the oxidative processing. Results from particle size analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and salt solubility indicated that protein cross-linking and fragmentation occurred during the oxidation of myofibrils. XPS analysis of C 1s, N 1s, and O 1s spectra suggested that surface chemical function concentrations changed significantly because of the modification of amino acid side chains that rendered protein cross-links and fragmentation and phospholipid alteration. Analysis of the correlation between the surface chemical composition and parameters of particle size distributions confirmed that protein carbonylation and phospholipid alteration were involved in protein surface modification. Results of the microstructure analysis were in agreement with those of particle size and XPS analysis.

Advances in nonfouling materials: perspectives for the food industry

Fouling of complex food components onto food-processing materials affects food quality, food safety, and operating efficiency. Developments in nonfouling and fouling-release materials for biomedical and marine applications enable the potential for adaptation to food applications; however, challenges remain. The purpose of this review is to present different strategies to prevent fouling and/or facilitate foulant removal with a critical point of view for an application of such materials on food-processing surfaces. Nonfouling, self-cleaning, and amphiphilic materials are reviewed, including an explanation of the mechanism of action, as well as inherent limitations of each technology. Perspectives on future research directions for the design of food processing surfaces with antifouling and/or fouling release properties are provided.