Effect of Freeze-Drying on Quality and Grinding Process of Food Produce: A Review

Abstract

Freeze-drying is an important processing unit operation in food powder production. It offers dehydrated products with extended shelf life and high quality. Unfortunately, food quality attributes and grinding characteristics are affected significantly during the drying process due to the glass transition temperature (during drying operation) and stress generated (during grinding operation) in the food structure. However, it has been successfully applied to several biological materials ranging from animal products to plants products owning to its specific advantages. Recently, the market demands for freeze-dried and ground food products such as spices, vegetables, and fruits are on the increase. In this study, the effect of the freeze-drying process on quality attributes, such as structural changes, the influence of glass transition during grinding, together with the effect on grinding efficiency in terms of energy requirement, grinding yield, and morphological changes in the powder as a result of temperature, drying time were discussed. An overview of models for drying kinetics for freeze-dried food sample, and grinding characteristics developed to optimize the drying processes, and a prediction of the grinding characteristics are also provided. Some limitations of the drying process during grinding are also discussed together with innovative methods to improve the drying and grinding processes.

Isolation of Industrial Important Bioactive Compounds from Microalgae

“…The microalgae are frozen to solidify the material within before freeze-drying. The moisture content of the microalgae is decreased slowly at low-temperature, maintaining the solid structure and the quality of the product [ 27 ].…”

Isolation of Industrial Important Bioactive Compounds From Microalgae: A Review

“…The microalgae are frozen to solidify the material within before freeze-drying. The moisture content of the microalgae is decreased slowly at lowtemperature, maintaining the solid structure and the quality of the product [27].…”

Scavenging activity nano complex compounds of kelor (Moringa oleifera Lamk.) leaves and seeds

“…Freezedrying has become a welcomed idea especially in the pharmaceutical and other bioproduct industries and gradually becoming a well-utilized processing method in the food industries owing to the assumptions of product quality good perform. The initial freezing process involves the formation of ice nuclei which are dependent on factors such as the cooling rate, interfacial energy, and the interfacial morphology or the nano structure of foreign bodies (Oyinloye et al, 2020).…”