Techniques for extraction of bioactive compounds from plant materials: A review

The use of bioactive compounds in different commercial sectors such as pharmaceutical, food and chemical industries signifies the need of the most appropriate and standard method to extract these active components from plant materials. Along with conventional methods, numerous new methods have been established but till now no single method is regarded as standard for extracting bioactive compounds from plants. The efficiencies of conventional and non-conventional extraction methods mostly depend on the critical input parameters; understanding the nature of plant matrix; chemistry of bioactive compounds and scientific expertise. This review is aimed to discuss different extraction techniques along with their basic mechanism for extracting bioactive compounds from medicinal plants.     

Extraction and purification of high added value compounds from by-products of the winemaking chain using alternative/nonconventional processes/technologies

Grape byproducts are today considered as a cheap source of valuable compounds since existent technologies allow the recovery of target compounds and their recycling. The goal of the current article is to explore the different recovery stages used by both conventional and alternative techniques and processes. Alternative pre-treatments techniques reviewed are: ultrasounds, pulsed electric fields and high voltage discharges. In addition, nonconventional solvent extraction under high pressure, specifically, supercritical fluid extraction and subcritical water extraction are discussed. Finally alternative purification technologies, for example membrane processing were also examined. The intent is to describe the mechanisms involved by these alternative technologies and to summarize the work done on the improvement of the extraction process of phenolic compounds from winery by-products. With a focus on the developmental stage of each technology, highlighting the research need and challenges to be overcome for an industrial implementation of these unitary operations in the overall extraction process. A critical comparison of conventional and alternative techniques will be reviewed for ethe pre-treatment of raw material, the diffusion of polyphenols and the purification of these high added value compounds. This review intends to give the reader some key answers (costs, advantages, drawbacks) to help in the choice of alternative technologies for extraction purposes.     

Emerging technologies to extract high added value compounds from fruit residues: Sub/supercritical,ultrasound-, and enzyme-assisted extractions

Food waste is a growing problem for the food industry, leading to an increase of pollution and economic problems. Fruits and vegetables are very rich in bioactive compounds having many benefits for humans. These biocompounds can be found not only in the fruit/vegetable itself but also in its wastes, after processing. Nonetheless, the conventional extraction methods are highly problematic, due to solvent consumption, long extraction time, and low extraction yields, making it necessary to develop new extraction techniques. In this review, we aim to review the most recent literature on the extraction of bioactive compounds from fruit peels and seeds, using sub/supercritical fluids, ultrasound, and enzymes.     

Recent insights for the green recovery of inulin from plant food materials using non-conventional extraction technologies: A review

Inulin constitutes an important food ingredient, widely used for its fiber content, and its ability to substitute fat and sugar ingredients. Traditionally, industrial inulin production from chicory roots requires high extraction temperature (70–80 °C) and long extraction time (1–2 h). This conventional extraction is generally accompanied with the presence of a large amount of impurities in the extracted juice, mainly due to the application of high temperature, requiring thus further purification steps. To overcome these issues, developing novel extraction technologies, consuming less energy, faster, and providing high yield and purity, is of paramount importance to meet the requirements of a green extraction concept. In this review, the feasibility of using conventional and new promising technologies (enzyme assisted extraction, ultrasounds, microwaves, supercritical fluid extraction, and pulsed electric fields) to recover inulin from plant food materials and by-products from an environmental and economical point of view will be discussed.Industrial relevanceInulin is widely used in food industries mainly due to its ability to substitute fat and sugar ingredients. However, the current industrial recovery process of this molecule is mainly carried out by diffusion in hot water (70–80 °C), followed by a relatively complex purification process, due to the presence of a large amount of impurities generated by the application of high temperatures. The need for obtaining greener, sustainable, and viable processes has led food scientists to develop new processes in full correspondence with the green extraction concept based on the use of non-conventional technologies (i.e. pulsed electric fields, ultrasounds, microwaves, etc). The submitted review discusses the potential of some of these new promising technologies to allow the industrial sustainability and green recovery of inulin, which have as benefits: energy- and time-saving along with higher yields and milder temperatures, reducing thus the subsequent purification steps.     

A comparative study on the structure of Saccharomyces cerevisiae under nonthermal technologies: high hydrostatic pressure, pulsed electric fields and thermo-sonication

Nonthermal technologies are becoming more popular in food processing; however, little detailed research has been conducted on the study of the lethal effect of these technologies on certain microorganisms. Saccharomyces cerevisiae is a yeast related to spoilage of fruit products such as juices; novel technologies have been explored to inactivate this yeast. Three nonthermal technologies, high hydrostatic pressure (HHP), pulsed electric fields (PEF) and thermo-sonication (TS), were used to evaluate and to compare the structural damage of yeast cells after processing. Processing conditions were chosen based on previous experiments to ensure the death of cells; HHP was conducted at 600 MPa for 7 min (room temperature, 21 °C); for PEF, 30.76 kV/cm at 40 °C and 21 pulses (2 μs each), and finally for TS the conditions were 120 μm, 60 °C and 30 min in continuous and pulsed modes; all treatments were applied in apple juice. Cells were prepared for electron microscopy using an innovative and short microwave assisted dehydration technique. Scanning electron microscopy showed the degree of damage to the cells after processing and illustrated the important and particular characteristics of each technology. Cells treated with high hydrostatic pressure showed a total disruption of the cell membrane, perforation, and release of the cell wall; scars were also observed on the surface of the pressurized cells. PEF treated cells showed less superficial damage, with the main changes being the deformation of the cells, apparent fusion of cells, the formation of pores, and the breakdown of the cell wall in some cells. Finally, the thermo-sonicated cells showed a similar degree of cellular damage to their structure regardless of whether the TS was applied continuously or pulsed. The main characteristics of cellular death for this technology were the erosion and disruption of the cellular membrane, formation of orifices on the surface, lysis of cells causing the release of intracellular contents, roughness of the cell membrane, and displacement of cell debris to the surface of other cells. This study confirms some theories about cell inactivation and presents new and detailed results about nonthermal technologies, but also shows that after using the above mentioned conditions, recovery of cells, specifically those that are pressurized and thermo-sonicated, it is not possible to do it following the high extent of damage observed in the entire population. Furthermore, a faster methodology that was used in sample preparation for electron microscopy provided high quality resolution images, allowing closer study of the detail of structural lethal effects on treated cells.     

Volatile compounds in ground beef subjected to high pressure processing: A comparison of dynamic headspace and solid-phase microextraction

The effect on the volatile profile of cooked beef meat, previously subjected to high pressure (400 MPa, 10 min at 12 °C) followed by a 3-d refrigerated storage, was investigated by comparing two extraction techniques i.e. dynamic headspace and solid-phase microextraction. Dynamic headspace was more efficient in extracting 2,3-butanedione and secondary alcohols. Solid-phase microextraction, being more efficient in extracting substances such as 1-alcanols, ethyl esters and acids, permitted to better categorize the effects caused in the volatile fraction by refrigerated storage and high pressure processing.     

Comparative evaluation of microwave‐assisted extraction and preheated solvent extraction of bioactive compounds from a plant material: a case study with cabbages

Preheated solvent extraction (PSE) was evaluated via the analysis of the extraction kinetics, microstructure of extracted samples and energy consumption as alternative to microwave‐assisted extraction (MAE). Cabbage outer leaves and ethanol were used as test material and extraction solvent, respectively. MAE was first optimised in terms of glucosinolates and phenolics yields; total antioxidant activity of the extracts was also assessed. MAE at a specific absorbed power of 0.37 W g^?1 for 9 min was selected as optimum condition to extract glucosinolates and phenolics, while PSE was optimised at 6 min of the extraction. The highest normalised total glucosinolates and phenolic contents as well as antioxidant activities of the extracts obtained via MAE were not significantly different from those obtained via PSE. Confocal laser scanning microscopy revealed no significant differences in cabbage cell damages rendered by MAE and PSE. PSE nevertheless exhibited slightly higher specific energy consumption than MAE.     

铁蛋白纳米笼分子装载途径及食品活性物质递送的研究进展

铁蛋白(ferritin)是一种广泛存在于动物、植物和微生物中的多亚基笼形结构蛋白,具有调节体内铁代谢平衡的功能,同时可以保护细胞免受因各种环境胁迫而导致的细胞氧化损伤.近年来,随着研究的深入,铁蛋白独特的纳米笼形结构以及特殊的理化性质使其成为一种具有广泛应用前景的新型蛋白质纳米载体材料.文章对铁蛋白的分子结构和功能进...     

The importance of ATP-related compounds for the freshness and flavor of post-mortem fish and shellfish muscle: A review

ATP degradation is one of the most important biochemical changes in the post-mortem muscle of fish and shellfish. This process has long been recognized as an accurate way to evaluate freshness of fish and shellfish product. This review updates and condenses the overall history and recent advances in understanding the role of ATP-related compounds in post-mortem fish and shellfish muscle including a discussion of key analytical methods, their use as a freshness indicator, their roles in flavor enhancement, the factors affecting their transitions, and the possible mechanisms responsible for their impact on flavor and freshness. Moreover, some challenges and future directions for research regarding ATP-related compounds in fish and shellfish flavor and freshness are presented. With increasing consumer demands for fresh products with extended shelf life, understanding the relationships between ATP-related compounds and their involvement in the freshness and umami taste is a prerequisite for assuring the high quality of fish and shellfish.     

Supercritical fluid extraction and hydrodistillation for the recovery of bioactive compounds from Lavandula viridis L’Hér

The chemical profiles of bioactive essential oil and extracts obtained by hydrodistillation (HD) and supercritical fluid extraction (SFE), respectively, from Lavandula viridis were compared. The SFE was performed at 40 °C and at extraction pressures of 12 or 18 MPa in two different separators. Evaluation of the essential oil and SFE extracts by GC–FID and GC–IT–MS revealed that oxygen-containing monoterpenes were the major constituents in both cases, but there were important differences between the chemical profiles produced by the different extraction techniques. More compounds were isolated by HD but higher yields were achieved by SFE. Camphor was the main component identified in the essential oil (31.59 ± 1.32%), and in extracts from the first (1.61 ± 0.34%) and second SFE separators (22.48 ± 1.49%) at 12 MPa. In contrast, the first separator SFE extract at 18 MPa (heavy compounds) was dominated by myrtenol (5.38 ± 2.04%) and camphor (4.81 ± 1.93%), whereas the second separator SFE extract (volatiles) was dominated by verbenone (13.97 ± 5.27%). The essential oil and heavy compound extracts from the first separator possessed antioxidant and anti-cholinesterase activities. Our data show that phytochemicals from the aerial parts of L. viridis could be developed as natural antioxidant and anti-cholinesterase drugs, with particular applications in the symptomatic treatment of Alzheimer’s disease.     

Rheology of Aloe barbadensis Miller: A naturally available material of high therapeutic and nutrient value for food applications

Due to the potential applications of Aloe barbadensis Miller (Aloe vera) in cosmetics, pharmaceutical and food products, the study of its rheology is important. Recently, many commercial food-product producers have boosted up the usage of Aloe vera gel or juice in one form or the other due to its nutrient ingredients. The present study reports the rheological characteristics of native Aloe gel and juice under dynamic and steady shear. The damping of the elastic moduli and viscous moduli at various temperatures for the Aloe gel under oscillatory shear tests have been reported, for the first time, which were observed due to the presence of weak, fibrous and random structure of polysaccharides in it. The moduli for gel increased with increasing temperature and that for juice decreased with temperature. Prior to attaining the plateau region after certain shear rate, Aloe vera gel and juice exhibited shear thinning behavior. The flow behavior index for Aloe gel samples was found to be 0.1 in the shear thinning region.