Changes of carotenoid content in carrots after application of pulsed electric field treatments

Non-thermal technologies for the conservation of açai pulp and derived products: A comprehensive review

Açai (Euterpe oleracea) is one of the main sustainable extractive crops in the Amazon region, widely consumed by the local population and a significant export product. This review presents the current knowledge regarding nonthermal technologies employed in açai processing. This review aims to discuss and compare the main results attained by the application of HPP, ultrasound, ozone, UV light, cold plasma, and pulsed electric field on microbial inactivation, enzymatic inhibition, and the content of anthocyanin and other bioactive compounds after açai pulp processing. The discussion compares these technologies with pasteurization, the current main technology applied to açai sanitization. This review shows that there are still many gaps to be filled concerning açai processing in thermal and non-thermal technologies. Data analysis allowed the conclusion that pasteurization and HPP are, up to now, the only technologies that enable a 5-log CFU reduction of yeasts, molds, and some bacteria in açai. However, no study has reported the inactivation of Trypanosoma cruzi, which is the major gap found in current knowledge. Other technologies, such as pulsed electric field, cold plasma, and ultrasound, require further development and process intensification studies to be as successful as HPP and pasteurization.

Proposing Signaling Molecules as Key Optimization Targets for Intensifying the Phytochemical Biosynthesis Induced by Emerging Nonthermal Stress Pretreatments of Plant-Based Foods: A Focus on γ-Aminobutyric Acid

Emerging evidence has confirmed the role of emerging nonthermal stressors (e.g., electromagnetic fields, ultrasonication, plasma) in accumulating bioactive metabolites in plant-based food. However, the signal decoding mechanisms behind NonTt-driven phytochemical production remain unclear, hindering postharvest bioactive component intensification. This study aims to summarize the association between signaling molecules and bioactive secondary metabolite production under nonthermal conditions, demonstrating the feasibility of enhancing phytochemical accumulation through signaling molecule crosstalk manipulation. Nonthermal elicitors were found to be capable of inducing stress metabolisms and activating various signaling molecules, similar to conventional abiotic stress. A simplified pathway model for nonthermally induced γ-aminobutyric acid accumulation was proposed with reactive oxygen species and calcium signaling being versatile pathways responsive to nonthermal elicitors. Manipulating signal molecules/pathways under nonthermal conditions can intensify phytochemical biosynthesis. Further research is needed to integrate signaling molecule responses and metabolic network shifts in nonthermally stressed plant-based matrices, balancing quality modifications and intensification of food functionality potential.

A Pulsed Electric Field Accelerates the Mass Transfer during the Convective Drying of Carrots: Drying and Rehydration Kinetics, Texture, and Carotenoid Content

The pulsed electric field (PEF) is a non-thermal food processing technology that induces electroporation of the cell membrane thus improving mass transfer through the cell membrane. In this study, the drying and rehydration kinetics, microstructure, and carotenoid content of carrot (Daucus carota) pretreated by PEF during convective drying at 50 °C were investigated. The PEF treatment was conducted with different field strengths (1.0-2.5 kV/cm) using a fixed pulse width of 20 µs and at a pulse frequency of 50 Hz. The PEF 2.5 kV/cm showed the shortest drying time, taking 180 min, whereas the control required 330 min for the same moisture ratio, indicating a 45% reduction in drying time. The rehydration ability also increased as the strengths of PEF increased. PEF 2.5 kV/cm resulted in 27.58% increase in moisture content compared to the control after rehydration (1 h). Three mathematical models were applied to the drying and rehydration data; the Page and Peleg models were selected as the most appropriate models to describe the drying and rehydration kinetics, respectively. The cutting force of the sample was decreased as the strength of PEF increased, and a more homogeneous cellular structure was observed in the PEF pretreatment group. The reduction in drying time by PEF was beneficial to the carotenoid content, and PEF 2.5 kV/cm showed the highest preservation content of carotenoid. Overall, these results suggested that the pretreatment of PEF and the drying and rehydration rate influence the quality of products, functional components, and cellular structure.

Emerging Postharvest Technologies to Enhance the Shelf-Life of Fruit and Vegetables: An Overview

Quality losses in fresh produce throughout the postharvest phase are often due to the inappropriate use of preservation technologies. In the last few decades, besides the traditional approaches, advanced postharvest physical and chemical treatments (active packaging, dipping, vacuum impregnation, conventional heating, pulsed electric field, high hydrostatic pressure, and cold plasma) and biocontrol techniques have been implemented to preserve the nutritional value and safety of fresh produce. The application of these methodologies after harvesting is useful when addressing quality loss due to the long duration when transporting products to distant markets. Among the emerging technologies and contactless and non-destructive techniques for quality monitoring (image analysis, electronic noses, and near-infrared spectroscopy) present numerous advantages over the traditional, destructive methods. The present review paper has grouped original studies within the topic of advanced postharvest technologies, to preserve quality and reduce losses and waste in fresh produce. Moreover, the effectiveness and advantages of some contactless and non-destructive methodologies for monitoring the quality of fruit and vegetables will also be discussed and compared to the traditional methods.

α-Carotene: a valuable carotenoid in biological and medical research

α-Carotene, one of the C₄₀ carotenes, is a natural lipid-soluble terpene. The chemical structure of α-carotene is based on the unsaturated polyene chain skeleton, with an ε-ring and a β-ring on each side of the skeleton. α-Carotene is widely found in dietary fruits and vegetables, and the concentration depends on the plant species. In addition, processing methods and storage conditions used in the food and medical industries can alter the concentration of α-carotene in raw materials. This review of α-carotene summarizes the major studies on chemical structure, source, extraction, detection, biosynthesis, processing effect, bioactivity, medicine, and biotechnology. Whether α-carotene supplementation or a diet rich in fruits and vegetables has a positive effect on the prevention of cancer, cardiovascular disease, and other diseases is the focus of this study. © 2022 Society of Chemical Industry.

Carotenoid fates in plant foods: Chemical changes from farm to table and nutrition

Carotenoids in plant foods are sources of pro-vitamin A and nutrients with several health benefits, including antioxidant and anticancer activities. However, humans cannot synthesize carotenoids de novo and must obtain them from the diet, typically via plant foods. We review the chemical changes of carotenoids in plant foods from farm to table and nutrition, including nutrient release and degradation during processing and metabolism in vivo. We also describe the influencing factors and proposals corresponding to enhancing the release, retention and utilization of carotenoids, thus benefiting human health. Processing methods influence the release and degradation of carotenoids, and nonthermal processing may optimize processing effects. The carotenoid profile, food matrix, and body status influence the digestion, absorption, and biotransformation of carotenoids in vivo; food design (diet and carotenoid delivery systems) can increase the bioavailability levels of carotenoids in the human body. In this review, the dynamic fate of carotenoids in plant foods is summarized systematically and deeply, focusing on changes in their chemical structure; identifying critical control points and influencing factors to facilitate carotenoid regulation; and suggesting multi-dimensional strategies based on the current state of food processing industries to achieve health benefits for consumers.

Pulsed light of near-infrared and visible light wavelengths induces the accumulation of carotenoids in tomato fruits during post-treatment time

Pulsed light (PL) is proposed as a novel strategy for the food industry to enhance the antioxidant potential of fruits and vegetables for industrial uses. The main aim of this work is to evaluate the impact of postharvest PL treatments of different spectral ranges on the carotenoid concentration as well as quality attributes of tomatoes during post-treatment time. Doses of wide-spectrum light (180-1100 nm), full-spectrum without ultraviolet (UV)-C wavelengths (305-1100 nm), and visible (VIS) + near-infrared light (NIR) (400-1100 nm) were compared. Total carotenoids, lycopene, and chlorophyll contents were spectrophotometrically assessed just after treatments and 1, 5, and 10 days post-treatment. PL treatments accelerated the accumulation of both total carotenoids and lycopene concentrations in tomato fruits. Nevertheless, the efficacy of PL depended on the applied spectral range. Tomato subjected to VIS + NIR treatment exhibited the greatest enhancement in total carotenoids (31 %) and lycopene (35 %) content at day 5 post-treatment and quality attributes were not affected. Conversely, UV-light exposure did not enhance carotenoid concentrations. These results evidenced that VIS + NIR treatments induced a faster accumulation of carotenoids without negatively affecting tomato quality attributes. PRACTICAL APPLICATION: The integration of visible and near-infrared (VIS + NIR) light filters in pulsed light (PL) processing allows enhancing the accumulation of bioactive compounds in tomato tissues in a sustainable way, which can be processed to obtain derived products (e.g., juices, purees) with health-promoting properties. PL technology is characterized by a lack of residual compounds and the absence of applying chemicals potentially harmful to humans. Industries can attract the attention of consumers through their application, which allows offering this added value.

The impact of aromatic plant-derived bioactive compounds on seafood quality and safety

Plant-derived bioactive compounds have been extensively studied and used within food industry for the last few decades. Those compounds have been used to extend the shelf-life and improve physico-chemical and sensory properties on food products. They have also been used as nutraceuticals due to broad range of potential health-promoting properties. Unlike the synthetic additives, the natural plant-derived compounds are more acceptable and often regarded as safer by the consumers. This chapter summarizes the extraction methods and sources of those plant-derived bioactives as well as recent findings in relation to their health-promoting properties, including cardio-protective, anti-diabetic, anti-inflammatory, anti-carcinogenic, immuno-modulatory and neuro-protective properties. In addition, the impact of applying those plant-derived compounds on seafood products is also investigated by reviewing the recent studies on their use as anti-microbial, anti-oxidant, coloring and flavoring agents as well as freshness indicators. Moreover, the current limitations of the use of plant-derived bioactive compounds as well as future prospects are discussed. The discoveries show high potential of those compounds and the possibility to apply on many different seafood. The compounds can be applied as individual while more and more studies are showing synergetic effect when those compounds are used in combination providing new important research possibilities.

A Critical Review on Pulsed Electric Field: A Novel Technology for the Extraction of Phytoconstituents

Different parts of a plant (seeds, fruits, flower, leaves, stem, and roots) contain numerous biologically active compounds called “phytoconstituents” that consist of phenolics, minerals, amino acids, and vitamins. The conventional techniques applied to extract these phytoconstituents have several drawbacks including poor performance, low yields, more solvent use, long processing time, and thermally degrading by-products. In contrast, modern and advanced extraction nonthermal technologies such as pulsed electric field (PEF) assist in easier and efficient identification, characterization, and analysis of bioactive ingredients. Other advantages of PEF include cost-efficacy, less time, and solvent consumption with improved yields. This review covers the applications of PEF to obtain bioactive components, essential oils, proteins, pectin, and other important materials from various parts of the plant. Numerous studies compiled in the current evaluation concluded PEF as the best solution to extract phytoconstituents used in the food and pharmaceutical industries. PEF-assisted extraction leads to a higher yield, utilizes less solvents and energy, and it saves a lot of time compared to traditional extraction methods. PEF extraction design should be safe and efficient enough to prevent the degradation of phytoconstituents and oils.