Trends in Approaches to Assist Freeze-Drying of Food: A Cohort Study on Innovations

Abstract

Freeze drying has been a very successful technology in the food and pharma industries, particularly owing to the benefits it offers in terms of product quality. It is most recommended for high value foods and those that contain heat-sensitive ingredients. Over the years, to meet industry requirements, several variants of the freeze drying technology have been developed, even to meet specific drying applications. The process of freeze drying is highly energy-intensive and time-consuming. Nevertheless, innovative techniques are available with the potential to produce products at reduced drying times and lower cost, whilst being environment-friendly and maintaining freeze dried quality. This review summarizes advances in the application of infrared, microwave, ultrasound, pulsed electric field, and other techniques as pre-treatments and/or to assist conventional freeze drying processes. Freeze drying combined with other techniques can provide more benefits in terms of energy, time, and cost savings. The most important benefit is that it can maintain the quality of the end-product by conserving its sensorial properties and retaining more nutrients.In this review article, comparative studies have been presented to describe these aspects. Such techniques to assist the freeze drying process can be linked well with sustainable food processing strategies, particularly considering a significant reduction in energy requirements.

Recent Developments in the Hybridization of the Freeze-Drying Technique in Food Dehydration: A Review on Chemical and Sensory Qualities

“…Freeze-drying (FD) (lyophilization) is a technique used to remove water from frozen material by sublimating ice crystals under high vacuum pressure and low temperature. In FD, the material is first frozen, after which the water is removed using sublimation (primary drying) and then using desorption (secondary drying) [ 1 , 2 ]. The most widespread applications of freeze-drying are in the food and pharmaceutical industries.…”

“…The most widespread applications of freeze-drying are in the food and pharmaceutical industries. It is also useful for a variety of products in addition to food and bulk pharmaceuticals, such as flowers, cultured microorganisms, medical equipment, and cosmetics, particularly, chemicals, pigments, and enzymes [ 1 ]. The widespread use of freeze-drying in the food industry is due to some well-known benefits over other drying methods.…”

“…Food dehydration must provide good retention of vital food properties, including bioactive compounds, physical shape, and sensory quality. FD guarantees the long-term functionality of various biological materials, particularly foods with high value and those with constituents that are heat-sensitive [ 1 , 3 , 4 ]. According to the available literature, freeze-drying is an ideal method for food dehydration, allowing for long shelf-life, acceptable nutrient retention, and minimal shrinkage that creates a porous product with excellent rehydration capacity and aqueous solubility, soft texture, and reduced weight for storage [ 1 , 2 , 5 , 6 ].…”

“…FD guarantees the long-term functionality of various biological materials, particularly foods with high value and those with constituents that are heat-sensitive [ 1 , 3 , 4 ]. According to the available literature, freeze-drying is an ideal method for food dehydration, allowing for long shelf-life, acceptable nutrient retention, and minimal shrinkage that creates a porous product with excellent rehydration capacity and aqueous solubility, soft texture, and reduced weight for storage [ 1 , 2 , 5 , 6 ]. Most degradative activities, including protein degradation, microbial action, enzymatic reaction, and non-enzymatic browning, are constrained or even prevented by the absence of liquid water and the low temperature during freeze-drying [ 7 ].…”

Onion and Apple Functional Ingredients Intake Improves Antioxidant and Inflammatory Status and Vascular Injury in Obese Zucker Rats

“…In addition, freeze-drying is the best dehydration method to preserve nutritional qualities [ 12 , 13 ]. Therefore, the combination of innovative food processing technologies with freeze-drying allows to obtain functional food ingredients of plant derived food products [ 14 ]. Onions and apples are an essential source of nutrients and bioactive compounds (such as phenolic compounds) and dietary fibre.…”