Nanofluid research advances: Preparation, characteristics and applications in food processing

[Display omitted] •Nanofluids with low viscosity and density are desirable.•Two-stage method for nanofluid preparation could be more economical.•Nanofluid based fruit juice pasteurization and sterilization is effective but less explored.•Nanofluid composition needs standardization for developing a non-toxic process.•Environmental impact in terms of energy efficiency and toxicity not fully explored. There has been growing interest and substantial improvement in thermal processes for enhancing the heat transfer rate in food industry applications. The replacement of conventional heat transfer fluids with nanofluids is now being considered as a novel and emerging solution to the heat transfer problem of the food processing sector. This review covers state-of-the-art methods for production and application of these nanofluids with emphasis on the decontamination of liquid foods. The review also discusses the influence of processing conditions such as temperature and nanoparticle concentration on the thermal and viscous characteristics of the developed nanofluids. Further, the effect of these developed nanofluids on the quality attributes of food materials has also been reviewed and analyzed. Based on the current technological status, certain knowledge gaps in nanofluid research have been identified, including controlled (shape and size) and systematic experimental studies, stability of nanofluids with increasing thermal cycles, increasing the compatibility of base fluid to nanomaterials, and toxicity and environmental impact assessment.