Food Engineering Reviews最新文献

For many high-pressure processes employing pressurized fluids, such as supercritical fluid extraction (SFE) of natural matrices with supercritical carbon dioxide (scCO₂), CO₂ plays a central role as a solvent, solubilizing agent, or medium for extracting and processing diverse food-type substances, in which the knowledge on the solubility behavior of multiple compounds at the varying process conditions is essential in the process design, but not completely understood. High-pressure solubility data in pure scCO₂ or cosolvent-modified CO₂ of distinct types of organic compounds found in or related to food (mainly vegetable oils, essential oils, carotenoids, phenolics, and vitamins) published in the last decade were reviewed, encompassing temperatures of 298–373 K and pressures up to 95 MPa. Crossover phenomena, solubility enhancements in cosolvent systems or those containing a co-solute, and the antisolvent feature of CO₂ are also discussed. Current models for the correlation of solubility data by semi-empirical and thermodynamic models are compared, and the limitations of each class of models are highlighted. Lipid-soluble substances (fatty acid esters, fatty acids, and essential oils) are the most CO₂-soluble food-type substances in contrast to polar and complex polyphenols and carotenoids. The investigated solutes can be obtained by SFE, separated by fractionation using scCO₂, or applied to enzymatic reactions and particle formation processes. It was concluded based on recent applications that improved SFE, effective separation factors for supercritical fractionation, better solubilization of reactive systems, and supersaturation conditions to obtain micronized particles could be established based on the solubility behavior of dissolved solutes in the supercritical media at high pressures.

Food packaging materials are crucial to maintaining food quality, as they play an important role in preventing food deterioration, dehydration, and oxidation. Unlike synthetic polymers, natural biopolymers, such as polysaccharides and proteins, are abundant and widespread resources that are nontoxic, biocompatible, and biodegradable. In food packaging, contact between packaging materials and moist foods can frequently degrade the performance of the materials. This has increased research into the development of hydrophobic biopolymer-based films. Here, we summarize the effective preparation strategies, mechanical and barrier properties, pH responsiveness, self-cleaning performance, and antibacterial and antioxidant functions of hydrophobic biopolymer-based films. The most effective methods for preparing hydrophobic biopolymer-based films are electrospinning with hydrophobically modified biopolymers, adding micro/nanofillers and hydrophobic compounds to the films, and hydrophobically modifying the films. These methods can even generate superhydrophobic films with excellent barrier properties. We also discuss the current opportunities and challenges presented by hydrophobic biopolymer-based films.

Capillary pressure plays a critical role in driving fluid flow in unsaturated porous (pores not saturated with liquids but also containing air/gas) structures. The role and importance of capillary pressure have been well documented in geological and soil sciences but remain largely unexplored in the food literature. Available mathematical models for unsaturated food systems have either ignored the capillary-driven flow or combined it with the diffusive flow. Such approaches are bound to impact the accuracy of models. The derivation of the microscale definition of capillary pressure is overviewed, and the limitations of using the microscale definition at the macroscale are discussed. Next, the factors affecting capillary pressure are briefly reviewed. The parametric expressions for capillary pressure as a function of saturation and temperature, developed originally for soils, are listed, and their application for food systems is encouraged. Capillary pressure estimation methods used for food systems are then discussed. Next, the different mathematical formulations for food systems are compared, and the limitations of each formulation are discussed. Additionally, examples of hybrid mixture theory–based multiscale models for frying involving capillary pressure are provided. Capillary-driven liquid flow plays an important role in the unsaturated transport during the processing of porous solid foods. However, measuring capillary pressure in food systems is challenging because of the soft nature of foods. As a result, there is a lack of available capillary pressure data for food systems which has hampered the development of mechanistic models. Nevertheless, providing a fundamental understanding of capillary pressure will aid food engineers in designing new experimental studies and developing mechanistic models for unsaturated processes.

Bovine α-lactalbumin (α-LA) is a small (MW 14,178) globular whey protein with good nutritional and functional properties. Its increased availability as a purified protein has made easier the study of the effects of different processing treatments on its structural and techno-functional properties. The consumer demand for fresh foods with longer shelf-life and good sensory qualities led to extensive research in the field of the so-called nonthermal technologies to inactivate microorganisms and enzymes. However, these technologies have also acquired great importance in the field of modification and improvement of structural, physicochemical, and techno-functional properties of food proteins. In this review, the effects of some nonthermal processes (high hydrostatic pressure, pulsed electric fields, high-intensity ultrasound, ultraviolet light, and atmospheric pressure cold plasma) on the properties of α-LA are examined, and the research needs in this field are indicated.

Air source heat pump drying systems in the agricultural production sector were reviewed in this study in terms of optimal designs, leading to the optimization of the heat pump drying process. Several intricate designs have been used to optimize the heat pump drying process. Multiple evaporators with multiple condensers, multiple drying chambers, cascade heat pump drying systems, hybrid heat pump drying systems, different configurations of the heat pump components, and refrigerants with lower environmental impacts have been used to accomplish optimal heat pump dryer designs and thereby optimum drying conditions for agricultural products.

The global meat substitute industry is estimated to be worth $8.1 billion by 2026. Prevailing health consciousness among consumers and their concern for the future environment has lifted the concept of meat alternatives from niche to the mainstream. Numerous research findings have emphasized the importance of meat alternatives or substitutes formulated from plant protein, animal cells, and insect-based sources, which emulate the nutritional composition and sensorial properties of animal meat. The current review discusses the necessity of meat substitutes, and their evolution, and bestows an outline of the ongoing research in this field. Novel protein sources such as vegetal proteins (cereal, pulses, oil seeds) and non-vegetal proteins (fungal, air protein, insect, myofibril) are reported to offer a viable alternative to animal meat. However, the functionalities of these proteins and the structuring technique influence the textural properties of the end products. Thus, the selection of a suitable technique is an important aspect in the formulation of the meat alternative. A thorough discussion of various structuring techniques for synthesizing matrixes and fibers with similar textural attributes to that of animal meat has been presented. Furthermore, limitations that confine consumers’ acceptance, the feasibility of scale-up, and the prerequisite for the regulatory framework for meat alternatives have also been pointed out. Overall, the ingredients and techniques of formulation of meat alternatives discussed in detail in this review can provide insight to the researchers and industries in formulating novel meat alternatives.

Tea (Camellia sinensis) is the most widely consumed beverage in the world, with an excellent source of bioactive compounds such as catechins, caffeine, and epigallocatechin. There is an increasing trend to extract these bioactive compounds to deliver them as value-added products. Generally, the extraction of polyphenols and other functional compounds from different parts of tea is carried out using different solvents (e.g., water, water–ethanol, ethanol, methanol, acetone, ethyl acetate, and acetonitrile). The extraction efficiency of functional compounds from tea depends on the type and polarity of the solvent as well as the applied process. Several conventional techniques, such as boiling, heating, Soxhlet, and cold extraction, are used to extract bioactive ingredients. However, these procedures are unsuitable for achieving high yields and biological activities due to the long extraction times of cold brewing and the high temperatures in other heating methods. Many efforts have been carried out in food and pharmaceutical industries to replace conventional extraction techniques with innovative technologies (e.g., microwave (MAE), ultrasonic (UAE), pressurized liquid (PLE), pulsed electric field (PEF), and supercritical fluid (SFE)), which are fast, safe, energy-saving, and can present eco-friendly characteristics. These innovative extraction techniques have proven to improve the recovery rate of phenolic-based antioxidant compounds from tea and increase their extraction efficiency. In this review, the application of novel processing technologies for the extraction of value-added compounds from tea leaves is reviewed. The advantages and drawbacks of using these technologies are also highlighted.

Annually, one-third of the food produced globally is lost or wasted. A considerable portion of global food waste comprises dry foods that are rejected due to their unattractive appearance. One effective technique to solve this problem is by developing dryers that consistently produce dry foods that are visually appealing and have a long shelf life. The beating heart of such dryers is a computer vision (CV) system that monitors the visual attributes of the food, in real time, during the drying process. Unfortunately, there are currently no real-time CV systems for monitoring the visual attributes of food during fluidized bed drying. This setback is linked to figure-ground separation challenges encountered while segmenting real-time images of the food. Sadly, when current CV systems are used to monitor visual attributes of food during fluidized bed drying, these CV systems fail miserably because they are not designed to account for three major dryer-dependent determinants—the layout, the state and pattern of motion, and the behavior of food materials within the image captured during fluidized bed drying. To solve this lingering problem, this paper reviewed various computer vision systems based on the three determinants. This study revealed that input images for the different CV systems can be categorized as being either static-type images or chaotic-type images. The CV systems were grouped into “Static-input offline CV systems,” “Static-input online CV systems,” and “Chaotic-input online CV systems.” Building on the insight gained while reviewing the three classes of CV systems, two novel AI-driven solutions for monitoring visual attributes of food, in real time, during fluidized bed drying were proposed. The first solution was a “two-pass” deep learning system that predicts visual attributes from segmented results. While the second solution was a “single-pass” deep learning system that by-passes the segmentation step, thus saving computational cost. When such AI-driven solutions are merged with a control system and then integrated with fluidized bed dryers, this union could open the gateway to intelligent drying, where dryers consistently produce high-quality dry foods. By extension, consistency in product quality could reduce global food losses and waste significantly.

Abstract

Separation of two fluids or particles from an emulsion is a fundamental process in many applications such as creaming of milk in dairy sector and extraction of various oils (avocado oil, palm oil, etc.) among many others. The aim of this paper is to elaborate on the development of various methods and technologies employed for the separation process including gravity, chemical, and centrifugation as well as the newer acoustic separation technology. Influential parameters affecting the performance, advantages, and disadvantages for each method will be discussed and compared. Various transducer configurations and corresponding experimental set-ups and operating parameters are also examined for acoustic separation. Accordingly, the future trend is proposed for introducing new transducer configurations to diminish or preferably eliminate the current disadvantages and barriers and to improve the separation process performance.