Advances of nanofluid in food processing: Preparation, thermophysical properties, and applications

Nanofluids (NFs) are homogenous mixes of solid nanoparticles as well as base fluid in which the size of the solid nanoparticles (NPs) is smaller than 100 nm. These solid NPs are intended to enhance the thermophysical characteristics and heat transmission attributes of the base fluid. The thermophysical characteristics of nanofluids are influenced by their density, viscosity, thermal conductivity and specific heat. These colloidal solutions of nanofluids include condensed nanomaterials such as nanoparticles, nanotubes, nanofibers, nanowires, nanosheets, and nanorods. The effectiveness of NF is significantly influenced by temperature, shape, size, type, as well as the concentration of NPs or the thermal characteristics of the base fluid. Compared to oxide NPs, metal NPs have superior thermal conductivity. Many of these investigations revealed that hybrid NFs had enhanced thermal conductivity than traditional ones. Thermal conductivity values are reduced by the formation of clusters in nanofluid. When compared to spherically formed nanoparticles, cylindrically shaped nanoparticles produced superior outcomes. In food industries, NFs could be used in various unit operations where heat needs to be transported from a heating or cooling medium to food product using a heat exchanger, as in freezing, pasteurization, refrigeration, drying, thawing, sterilization, and evaporation. The objective of this review is to analyze the recent developments in the research of nanofluids including innovative production methods, stability assessment, enhancement approaches, and thermophysical properties of nanofluids.