Food Engineering Reviews

Edible packaging plays an important role in protecting food products from physical, mechanical, chemical, and microbiological damages by creating a barrier against oxidation, water, and controlling enzymatic activation. The employment of active agents such as plant extracts, essential oils, cross-linkers, and nanomaterials in edible packaging promises to improve mechanical, physical, barrier, and other properties of edible materials as well as food products. In the current review, we have compiled information on the recent advances and trends in developing composite (binary and ternary) edible packaging for food application. Several types of active agents such as essential oils, plant extracts, cross-linking agents, and nanomaterials as well as their functions in edible packaging (active composite) have been discussed. The present study provides the collective information about the high- (high-pressure homogenizer, ultrasonication, and microfludizer) and low-energy (phase inversion temperature and composition and spontaneous emulsification) methods for developing nanoformulations. In addition, concepts of comprehensive studies required for developing edible coatings and films for food packaging applications, as well as overcoming challenges like consumer acceptance, regulatory requirements, and non-toxic scaling up to the commercial applications, have also been discussed.

Hybrid solar drying technology for food products is a clean and cost-effective replacement of highly energy intensive thermal dryers employed in agri-food processing chain. This involves the amalgamation of “only solar dryer” with various other energy harvesting systems like, biogas, heat pump, and thermal storage materials. This paper reviews the significance of hybrid solar dryers in terms of withstanding varied climatic and uncontrolled environmental conditions and their impact on drying characteristics of food products. From the appraisal, heat pump hybrid solar dryers proved to be more efficient, having wide range of drying temperature, and is suitable for heat-sensitive products. On the other hand, the advantages of biomass hybrid solar dryer lies in its ability to utilize cheap local resources for assisting the energy requirements and have low constructional cost. However, the state of art indicated that sanitary aspects of solar drying have not been explored much and should be encouraged. The presented review also explores the research scenario of relevant virtual platforms, applicable for simulating the dryer design and drying parameters. The important findings on modeling aspects of dryer design and thick layer drying of food products in solar dryer are also discussed. The economic assessment of presently available hybrid solar dryers showed competitive profitability metrics and equipment cost. Moreover, it is suggested for the promotion of energy-efficient hybrid solar dryers and its environmental benefits in the future to provide a benchmark for drying applications in food processing industries.

Foods in general are excellent sources for growth of fungi. These microorganisms can infect food and grow whenever the ideal temperature and moisture conditions for the particular species are present, causing large losses during storage. Furthermore, some fungal species produce mycotoxins, which are compounds that are toxic to humans and animals. The use of electron beams has been shown effective in decontaminating foods, packaging materials, plastic articles and surgical and biological materials, among others. The ease of handling, low cost and employment of electricity to generate ionizing radiation instead of radioactive material such as cobalt-60 are factors that have increased the use of this method. Because of the growing use of electron beams on foods to control pathogenic microorganisms, this review focuses on their use to control fungi that produce mycotoxins on foods, covering the suitable doses, effects on food quality, microorganism reduction rates, applications in the food industry and legislation on use and operational safety.

Pressure-assisted thermal processing (PATP) at T < 100°C can be used when enzyme inactivation and pasteurization by high pressure processing (HPP) is not feasible due to long processing times while PATP at T > 100°C can be used when bacterial spores inactivation is necessary. In PATP, the adiabatic compression/decompression heat increases/decreases temperature almost instantaneously, and the simultaneous application of high pressure (~600–700 MPa) and temperature (~100–120°C) accelerates spore inactivation. PATP effects on chemical changes are analyzed using a reaction kinetics approach including activation volume (V a) and activation energy (E a) values. Reaction rates increase or decrease with pressure for negative or positive V a values, respectively, while rate temperature and pressure sensitivity depends on the magnitude of E a and V a values, respectively. The complex effects of food matrix, pH, dissolved oxygen, and presence of antioxidants show that optimization of vitamin, pigment and flavor retention while ensuring PATP microbial and enzyme inactivation will require substantially more chemical reaction kinetics research.

Physical properties and stability are critical for delivering safe and healthy food to the consumers and thus is a theme that attracts food scientists for a long time. Recently, literature suggests that stability can be fully grasped only if food molecular dynamics and structure are taken into consideration, i.e. an appropriate understanding of the behaviour of food products requires knowledge of its composition, structure and molecular dynamics, through the three-dimensional arrangement of the various structural elements and their interactions. Food systems behaviour is strongly dependent on the water molecular dynamics. Understanding changes in location and mobility of water represents a significant step in food stability knowledge, since water “availability” profoundly influences the chemical, physical and microbiological quality of foods. Nuclear magnetic resonance has been presented as a powerful technique to investigate water dynamics and physical structures of foods through analysis of nuclear magnetisation relaxation times, because it provides information on molecular dynamics of different components in dense complex systems. The application of this technique may be very useful in predicting food systems physicochemical changes, namely texture, viscosity or water migration. This paper aims at reviewing some of the main aspects related to food physical properties and stability, and the role of water in these properties. More specifically, this paper intends to contribute to a deeper understanding of the relationship of molecular constituents–structure–function of food systems, contributing to the development of foods with improved functionality.

Plants and algae are the main sources of natural bioactive compounds used in the food and pharmaceutical industries. It is very important to achieve an efficient and safe technique to recover bioactive compounds while maintaining their quality and properties. Subcritical water extraction is the most promising engineering approach that offers an environmentally friendly technique for extracting various compounds from plants and algae. Application of pressurized water and high temperature in subcritical phase is able to modify the dielectric constant and polarity of the solvent which then contributes to a better extraction process. The technique improves the mass transfer rate and preserves the biological potency of the extracts. This article reviews current studies on the extraction of bioactive compounds from various species of plants and algae using the subcritical water technique and discusses its effects and benefits for the food and pharmaceutical industries.

Consumer demands and requirements by regulatory agencies to use more environmentally friendly and less polluting packaging have directed researchers to consider packaging materials that are naturally derived or made from renewable resources to replace or reduce use of synthetic polymers. Biodegradable and/or edible films have the potential to reduce some traditional synthetic polymeric packaging materials for specific applications. In recent years, biodegradable films prepared with animal and vegetable proteins have received increasing attention and are increasingly being used in the food-packaging industry due to their relative abundance, film-formation capacity, biodegradability, and nutritional value. However, the ideal protein films for food-packaging application should be strong, be elastic, and have very low permeability. The aim of this review is to offer a comprehensive view of recent state-of-the-art protein-based films as biodegradable materials applicable to food packaging with special reference to the application and combination of technological advances. Such advances include plasticization, cross-linking techniques, nanotechnology, and composite films. The results indicate that the functional properties of protein films are still not comparable with those of synthetic films, but there are promising potential methodologies that might further improve the mechanical and barrier properties of protein-based films. Nanocomposite films with well-controlled structures comprise an up-and-coming area of research. Research into nanocomposite film includes the opportunity to design biofilms and packaging materials with the precisely desired functional properties. By employing natural agents with antimicrobial and antioxidant properties, these materials promise to provide maintenance during storage time and to increase the shelf life of food products.

Whey is a by-product of cheese, casein, and yogurt manufacture. It contains a mixture of proteins that need to be isolated and purified to fully exploit their nutritional and functional characteristics. Protein-enriched fractions and highly purified proteins derived from whey have led to the production of valuable ingredients for many important food and pharmaceutical applications. This article provides a review on the separation principles behind both the commercial and emerging techniques used for whey protein fractionation, as well as the efficacy and limitations of these techniques in isolating and purifying individual whey proteins. The fractionation of whey proteins has mainly been achieved at commercial scale using membrane filtration, resin-based chromatography, and the integration of multiple technologies (e.g., precipitation, membrane filtration, and chromatography). Electromembrane separation and membrane chromatography are two main emerging techniques that have been developed substantially in recent years. Other new techniques such as aqueous two-phase separation and magnetic fishing are also discussed, but only a limited number of studies have reported their application in whey protein fractionation. This review offers useful insights into research directions and technology screening for academic researchers and dairy processors for the production of whey protein fractions with desired nutritional and functional properties.