In recent decades, microalgae species have focused the attention of several research groups and food industry as they are a great source of nutritionally valuable compounds. The use of environmentally friendly technologies has led to researchers and food industry to develop new alternative processes that can extract nutritionally valuable compounds from different sources, including microalgae. This note describes the potential use of some non-conventional methods including sub- and supercritical fluid extraction, pulsed electric fields, high-voltage electric discharges, high-pressure homogenization, ultrasound- and microwave-assisted extraction, which involve cell disruption to recover nutritionally valuable compounds from microalgae and can help to comply with criteria of green chemistry concepts and sustainability.

Gelatin, an important biopolymer derived from collagen, is widely used by various industries because of its functional and technological properties. The vast majority of commercial gelatin is derived from mammals, but due to many sociocultural and religious reasons, there is an increasing demand for alternative sources. The by-products generated by the fish-processing industry are a potential source for the production of gelatin. The high potential of fish gelatin production is due to the large quantities of collagen by-products generated. However, the main restriction to its use regards their lower rheological properties when compared to mammalian gelatin, which limits its range of applications. This review discusses the latest scientific literature about the main characteristics and functional properties of fish gelatin, which shows the main strategies used to improve its properties, as well as its applications and future potentials.

Physalis peruviana Linnaeus belongs to the family Solanaceae, and its potential cultivation is currently being explored due to its high productivity, sensory aspects and presence of several bioactive compounds. The shelf life of fresh physalis after harvesting is short, and its water content is high; therefore, osmotic dehydration, an alternative technology, could reduce the postharvest loss of this fruit. However, one factor that has hindered the application of this technology is the waxy skin of the fruit; in this context, the aim of the present work was to evaluate the effect of the pretreatment using an ultrasound probe (frequency, 20 kHz; amplitude, 80 %; for 30 min) on mass transfer during osmotic dehydration (ODU) and compare the results of the osmotic dehydration process without ultrasound (OD). The results showed that after 10 h, the loss of moisture was 47.6 ± 3.8 % and 46.1 ± 0.9 % for OD and ODU, respectively. The results for total sugar (normalized) showed a gain of 2.01 ± 0.22 and 2.05 ± 0.26 (g glucose g−1 of fruit) for OD and ODU, respectively. The carotenoid values were not observed to be influenced significantly by pretreatment; the ratios between the initial and final values of carotenoids were 0.74 ± 0.04 and 0.78 ± 0.06 for OD and ODU, respectively. The effective mass diffusivity of water calculated was 3.24 ± 0.49 × 10−10 m2 s−1 for OD and 3.34 ± 0.11 × 10−10 m2 s−1 for ODU, and the values founded were statistically equal (Tukey; p > 0.05). Additionally, the water activity and total color difference were measured for both the OD and ODU processes after 10 h, and statistically equal results were observed. Thus, for the conditions analyzed in this work, osmotic dehydration without and with an ultrasound probe as pretreatment showed no influence on the parameters studied. However, the food industry is constantly investigating new preservation technologies to improve and/or to replace of traditional food preservation techniques, and the treatment using ultrasonic waves has been used in conservation of fruits because it modifies the structure of the fruit increasing the water loss in the processing.

Incorporation of natural additives to active packaging systems or biopolymer-based edible films can modify the film structure and, as a result, modify their functionality and application to foods. This paper reviews the effect of the incorporation of natural additives from plant extracts or their isolated active compounds and vitamins on the functionality of edible films and the application of these films to foods. The final functionality of edible films is related to their bioactive properties (such as antioxidant, antimicrobial, and antibrowning activities) and functional properties (such as barrier to oxygen, carbon dioxide, and UV–vis light); water vapor permeability; tensile stress; elongation at break; and physical properties (such as opacity and color). Several categories of natural antioxidants found in plant, spices, and herbs (organic acids, plant natural extracts, and plant essential oils) have been incorporated into edible films and coatings, resulting in an improvement of the bioactive properties of the films. However, a wide range of plant natural sources with bioactive properties has not yet been characterized with respect to their ability to be applied directly on foods and used to develop active packaging or biopolymer-based edible films for preserving and adding value to foods. In addition, in vivo studies of the use of bioactive films to preserve the quality, shelf life, and nutritional value of foods remain limited.

Proteomic and peptidomic studies are emerging as an important part of the holistic approach to food science and technology and have been recently applied in the study and production of bioactive peptides. Food-derived bioactive peptides are short amino acid chains with a known sequence that may have one or more biological activities. The proteomic and peptidomic approach to bioactive peptide studies includes bioinformatics, chemometric tools and proteomic/peptidomic methods. A proteomic and peptidomic approach applied to the study of bioactive peptides allows optimizing their production and finding peptides of interest and contributes to understand the interaction mechanisms between receptor and bioactive peptides. The objective of this review was to describe recent analytical tools used for studying various aspects of food-derived biopeptides, emphasizing their production at laboratory and industrial scale.

The interest on novel biological preservation methods has been increasing during recent years, supported by research indicating that antagonistic microorganisms and their antimicrobial metabolites may have some potential use as natural preservatives as a way not only to control the growth but also to inactivate undesired microorganisms in food. Biopreservation using lactic acid bacteria (LAB) and/or their antimicrobial metabolites represents an alternative for improving food safety. These antimicrobial properties of LAB were derived from competition for nutrients and the production of one or more antimicrobial active metabolites such as organic acids (mainly lactic and acetic acid), hydrogen peroxide and also other compounds, such as bacteriocins and antifungal peptides. The important contribution of probiotic LAB in food preservation has been attracting much attention because of the nutritional qualities of the raw material through an extended shelf life of food and their ability to inhibit spoilage and foodborne pathogens, which is interesting for the food industry. In this review, we compiled the available data on the commonly used preservative and present the current knowledge regarding the antimicrobial compounds, especially bacteriocins, the mechanisms of the action and recent applications of antimicrobial compounds in food. The use of competitive microbiota as a biotechnological tool for food preservation may lead to improve the optimization and quality assurance of food products while at the same time retaining the sensory qualities of the product such as color, flavor, texture and nutritional value.

Peeling is one of the most important unit operations in tomato processing. Most recently, three novel tomato peeling methods were reported: infrared, ohmic heating and power ultrasound. Steam/hot water and lye peeling have been the most commercialized methods, but compared to steam peeling, lye peeling is more preferred and has gained widespread application among processors due to its association with higher product yields and better product quality. However, with the ever-tightening environmental protection laws, concerns have arisen in the recent years regarding lye usage as well as its disposal, which calls for alternative chemical-free peeling methods that can effectively peel the tomato while minimizing peeling losses and improving product quality. This review highlights the conventional methods used in tomato peeling, their efficacy and the potential applications of infrared, ohmic heating and power ultrasonics as a novel technology for tomato peeling.

Cleaning and disinfection are important opera- tions in food processing because of the significant contri- butions to product hygiene and food safety. The transfer of residues from surfaces into a product and the contamination with adhering microorganisms must therefore be avoided with sufficient certainty. Traditional methods for the removal of adherents and inactivation of microorganisms are based on thermal, mechanical, or chemical principles and are known to be time- and energy-consuming. This has resulted in a search for alternative methods that show pro- spective potential for their use in food-processing plants. This review gives an overview on such methods, which are based on physical principles. In dry-ice cleaning, for example, carbon dioxide snow pellets are blasted onto a surface to remove adherents through a combined action of thermal and mechanical effects, followed by dissolution of these adherents. Ice-pigging is a procedure where an ice/ water mixture is forced through pipes, heat exchangers, or other equipment to carry off adhered substances. Another method for physical cleaning, mainly described in context with membrane filtration, is to use vibration in the ultra- sonic frequency domain to reduce fouling and to stabilize permeate flux. Radiation from various sources (UV lamps, radionuclides, X-ray tubes) differs in its applicability and disinfection efficiency because of differences in energy and penetration depth. Cold plasma treatment is another prom- ising technology that is currently under investigation for cleaning and disinfection of surfaces of inorganic and organic materials.

Along the years, processing technologies for food preservation have been in constant development in order to meet current consumers’ claims. In this way, researchers have been continuously working to understand the effects of different novel emerging technologies tested on foods to ensure microbiological stability as well as high quality attributes. Among these novel technologies, pulsed electric fields (PEF) have shown to be a potential non-thermal treatment capable of preserving liquid foods with fresh-like characteristics. As a result, in the last decade, great technological advances have been accomplished regarding to PEF processing, such as improvement on the chamber designs, optimization of the process as well as achievement of high-quality-processed foods. This paper reviews the latest developments related to PEF technology for food preservation, the current designs of PEF treatment chambers, and modeling concepts applied for process optimization. In addition, some scaling-up considerations are included for future industrial implementation of PEF processing.

The incidence of food allergy has been increasing over the years, leading to a demand for methods aimed to reduce allergens from food products. The study of food processing on allergen reactivity has largely focused on thermal treatments; however, novel food processing techniques, such as a variety of nonthermal methods, are being explored to potentially create hypoallergenic products. Nonthermal methods are oftentimes advantageous, as they have the ability to retain organoleptic properties, such as nutrient content and flavor, that are frequently altered during thermal processing. Those afflicted with food allergy are typically required to completely eliminate problem foods from their diet, yet potential processing methods may allow consumption of those condemned foods by offering products with reduced allergen potency. This review highlights the efficacy of postharvest thermal and nonthermal treatments of foods in their ability to alter food allergen reactivity.