Extraction of antioxidant polyphenolic compounds from peanut skin using water-ethanol at high pressure and temperature conditions

Bioactive compounds of peanut skin in prevention and adjunctive treatment of chronic non-communicable diseases

The global prevalence of cancer continues to increase, so does its mortality. Strategies that can prevent/treat this condition are therefore required, especially low-cost and low-toxicity strategies. Bioactive compounds of plant origin have been presented as a good alternative. In this scenario, due to its abundant polyphenolic content (around 60 to 120 times greater than that of the grain), peanut skin by-products stand out as a sustainable source of food bioactives beneficial to human health. Investigated studies highlighted the importance of peanut skin for human health, its phytochemical composition, bioactivity and the potential for prevention and/or adjuvant therapy in cancer, through the advanced search for articles in the Virtual Health Library (VHL), Science direct and the Mourisco platform of the FioCruz Institute, from 2012 to 2022. Using the keywords, "peanut skin" AND "cancer" AND NOT "allergy", the words "peanut testa" and "peanut peel" were included replacing "peanut skin". 18 articles were selected from Plataforma Mourisco, 26 from Science Direct and 26 from VHL. Of these, 7 articles evaluated aspects of cancer prevention and/or treatment. Promising benefits were found in the prevention/treatment of chronic non-communicable diseases in the use of peanut and peanut skin extracts, such as cholesterolemia and glucose control, attenuation of oxidative stress and suppressive action on the proliferation and metabolism of cancer cells.

Valorization of Peanut Skin as Agricultural Waste Using Various Extraction Methods: A Review

Peanuts (Arachis hypogea) can be made into various products, from oil to butter to roasted snack peanuts and candies, all from the kernels. However, the skin is usually thrown away, used as cheap animal feed, or as one of the ingredients in plant fertilizer due to its little value on the market. For the past ten years, studies have been conducted to determine the full extent of the skin's bioactive substance repertoire and its powerful antioxidant potential. Alternatively, researchers reported that peanut skin could be used and be profitable in a less-intensive extraction technique. Therefore, this review explores the conventional and green extraction of peanut oil, peanut production, peanut physicochemical characteristics, antioxidant activity, and the prospects of valorization of peanut skin. The significance of the valorization of peanut skin is that it contains high antioxidant capacity, catechin, epicatechin resveratrol, and procyanidins, which are also advantageous. It could be exploited in sustainable extraction, notably in the pharmaceutical industries.

Pressurized Liquid Extraction for the Production of Extracts with Antioxidant Activity from Borututu (Cochlospermum angolense Welw.)

Borututu (Cochlospermum angolense Welw.) roots have been described as a rich source of phenolic compounds. Despite the potential of this plant for the production of bioactive extracts, studies reported until now have been scarce, and they have been based on the use of inefficient conventional extraction techniques. In this study, pressurized liquid extraction (PLE) was investigated for the production of borututu root extracts. Different temperatures (50–200 °C) and solvents (water, ethanol, and 50% ethanol:water) were applied. The total phenolic compound (TPC) content, the main phenolic compounds and the in vitro antioxidant activity of the extracts were evaluated. The results were compared with those obtained by conventional decoction with water. The highest concentrations of TPC and antioxidant activity were obtained with 50% ethanol:water, followed by water. The extract obtained with 50% ethanol:water at 150 °C had a TPC concentration of 343.80 mg/g and presented the largest antioxidant activity (1488 and 4979 µmol Trolox/g extract, determined by DDPH and ABTS assay, respectively). These values were considerably higher than those obtained by conventional decoction. Ellagic acid, and ellagic and methyl ellagic acid glycosides were the main phenolic compounds found in the extracts. Therefore, was PLE demonstrated to be a selective and efficient technique to obtain extracts with high concentrations of phenolic compounds and high antioxidant activity form borututu roots.

Insight into Green Extraction for Roselle as a Source of Natural Red Pigments: A Review

Roselle (Hibiscus sabdariffa L.) is a source of anthocyanins as red pigments that is extensively farmed in tropical and subtropical regions, including Indonesia, Malaysia, China, Thailand, Egypt, Mexico, and West India. The roselle plant contains a variety of nutrients, including anthocyanins, organic acids, pectin, etc. Due to the toxicity and combustibility of the solvents, traditional extraction methods for these compounds are restricted. Obtaining pure extracts is typically a lengthy procedure requiring many processes. Supercritical carbon dioxide (ScCO₂) extraction as a green technology is rapidly improving and extending its application domains. The advantages of this method are zero waste production, quicker extraction times, and reduced solvent consumption. The ScCO₂ extraction of natural pigments has great promise in food, pharmaceuticals, cosmetics, and textiles, among other uses. The ScCO₂ technique for natural pigments may also be advantageous in a variety of other contexts. Due to their minimal environmental risk, the high-quality red pigments of roselle rich in anthocyanins extracted using ScCO₂ extraction have a high sustainability potential. Therefore, the objective of this review is to increase knowledge related to the natural colorant of roselle as a substitute for chemically manufactured colorants using ScCO₂ as a green method. This article covers ScCO₂ extraction, particularly as it relates to the optimization of pigments that promote health. This article focuses on the high extraction efficiency of ScCO₂ extraction. Natural colorants extracted via ScCO₂ are regarded as safe compounds, especially for human consumption, such as novel functional food additives and textile and pharmaceutical colors.

Phenolic Fraction from Peanut (Arachis hypogaea L.) By-product: Innovative Extraction Techniques and New Encapsulation Trends for Its Valorization

Peanut skin is a by-product rich in bioactive compounds with high nutritional and pharmaceutical values. The phenolic fraction, rich in proanthocyanidins/procyanidins, is a relevant class of bioactive compounds, which has been increasingly applied as functional ingredients for food and pharmaceutical applications and is mostly recovered from peanut skins through low-pressure extraction methods. Therefore, the use of green high-pressure extractions is an interesting alternative to value this peanut by-product. This review addresses the benefits of the phenolic fraction recovered from peanut skin, with a focus on proanthocyanin/procyanidin compounds, and discusses the improvement of their activity, bioavailability, and protection, by methods such as encapsulation. Different applications for the proanthocyanidins, in the food and pharmaceutical industries, are also explored. Additionally, high-pressure green extraction methods, combined with micro/nanoencapsulation, using wall material derived from peanut industrial processing, may represent a promising biorefinery strategy to improve the bioavailability of proanthocyanidins recovered from underutilized peanut skins.

Simultaneous Optimization of Phenolic Compounds and Antioxidant Abilities of Moroccan Pimpinella anisum Extracts Using Mixture Design Methodology

Pimpinella anisum (anise) is a dense vegetal matrix with considerable amounts of bioactive components known for its pharmacological properties. The optimization of extraction constitutes an important key to improving efficacy and avoiding wasting time. Within this framework, the present study was designed to select the most appropriate extractor solvent mixture to extract phenolic and flavonoids using Mixture Design Methodology. The concerned responses were the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant ability examined by 2,2-diphenyl-l-picrylhydrazyl (DPPH) assay. Before mixture design optimization, a screening of solvents was conducted on ten polar and nonpolar solvents to choose the best solvents that give a maximum of total phenolic compounds. This first step has shown that water, ethanol and methanol were the best-used solvents. Later, an augmented centroid design investigated the solvent system’s optimization. The results of simultaneous optimization have shown that the ternary mixture containing 44% of water, 22% of ethanol and 34% of methanol was the most appropriate for simultaneous maximization of TPC, TFC and antioxidant activity with 18.55 mg GAE/g, 7.16 mg QE/g and 0.56 mg/mL, respectively. Our results have shown that using mixture design as an optimization technique was an excellent way to choose the most suitable mixture to extract bioactive compounds, which may represent a promising method of multi-purpose extraction, especially in the pharmaceutical and food sectors.

Peanut skin phenolics obtained by green solvent extraction: characterization and antioxidant activity in pure chia oil and chia oil in water (O/W) emulsion

BACKGROUND

The peanut skin (PS) is considered as an industrial waste with undervalued applications. Although several studies report potent antioxidant capacities of PS phenolics, the effectiveness in highly unsaturated lipid systems has not yet been evaluated. The objectives of the present study were two-fold: (i) to characterize a PS phenolic extract (PSE) obtained by means of a green technology and (ii) to evaluate its antioxidant efficacy on pure chia oil and chia oil in water (O/W) acid emulsion.

RESULTS

PSE was composed mainly of monomeric and condensed flavonoids (procyanidin and proanthocyanidin oligomers). PSE displayed strong antioxidant properties as measured by different reducing power and radical scavenging capacities [IC₅₀  = 0.36 μg dry extract (DE) mL^-1 for ferric reducing antioxidant power; IC₅₀  = 4.96 μg DE mL^-1 for 2,2-diphenyl-1-picrylhydrazyl (DPPH)^• ; IC₅₀  = 6.01 μg DE mL^-1 for 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS)^•+ ; IC₅₀  = 2.62 μg DE mL^-1 for HO^• ]. It also showed high antioxidant efficacy when tested in pure chia oil under accelerated oxidation conditions (Rancimat, 100 °C). When added to the O/W emulsions maintained at 40 °C for 15 days, the PSE was more effective than a synthetic antioxidant (tert-butylhydroquinone) with respect to minimizing the formation and degradation of lipid hydroperoxides.

CONCLUSIONS

The antioxidant efficacy of PSE was primarily attributed to the abundance of compounds with a high number of phenolic-OH groups. Because they were found to cover a relatively wide range of partition coefficients, the antioxidant properties could be also enhanced by effect of both interfacial and solubility phenomena. All of these features allow the potential use of PSE as a natural antioxidant in different types of foods, including acid emulsion systems. © 2021 Society of Chemical Industry.

An overview on extraction, composition, bioactivity and food applications of peanut phenolics

Peanuts contain a diverse and vast array of phenolic compounds having important biological properties. They are allocated mostly in the seed coat (skin), an industrial waste with minor and undervalued applications. In the last few years, a considerable amount of scientific knowledge about extraction, composition, bioactivities and health benefits of peanut skin phenolics has been generated. The present review was focused on four main aspects: a) extraction methods and technologies for obtaining peanut skin phenolics with an emphasis on green-solvent extraction processes; b) variations in chemical profiles including those due to genetic variability, extraction methodologies and process-related issues; c) bioactive properties, especially antioxidant activities in food and biological systems; d) update of promising food applications. The revision was also aimed at identifying areas where knowledge is insufficient and to set priorities for further research.

Extraction kinetics, physicochemical properties and immunomodulatory activity of the novel continuous phase transition extraction of polysaccharides from Ganoderma lucidum

Ganoderma lucidum polysaccharides (GLP) possess remarkable bioactivity and have been studied widely. However, the application of new technologies in the polysaccharide extraction has not been investigated. Herein, a novel continuous phase transition extraction (CPTE) technology was applied for the extraction of polysaccharides from Ganoderma lucidum. The extraction kinetics, physicochemical properties and immunomodulatory activity of GLP were evaluated. The kinetics results showed that the extraction process could be fitted to a two-site kinetic model due to the high R² values in the range of 0.9939-0.9999. Polysaccharides extracted by different technologies showed that GLP yield by CPTE could be significantly improved, which was 3.34 times and 2.68 times that of hot water and ultrasonic-assisted extraction, respectively. Molecular weight distribution analysis indicated that high molecular mass polysaccharide proportion by CPTE was the highest among the three extraction methods, which was 2.03 times and 3.41 times as much as that of the hot water and ultrasonic-assisted extraction. Morphology analysis showed that CPTE treatment caused disruption of most of the cells and effective release of intracellular components, implying that CPTE was beneficial to extract polysaccharides. Furthermore, the immunomodulatory assays demonstrated that GLP significantly enhanced the proliferation and production of NO, TNF-α and IL-6 in macrophages. Therefore, CPTE was more effective for extracting polysaccharides from Ganoderma lucidum than the common extraction.

Diversity of Chemical Structures and Biosynthesis of Polyphenols in Nut-Bearing Species

Nuts, such as peanut, almond, and chestnut, are valuable food crops for humans being important sources of fatty acids, vitamins, minerals, and polyphenols. Polyphenols, such as flavonoids, stilbenoids, and hydroxycinnamates, represent a group of plant-specialized (secondary) metabolites which are characterized as health-beneficial antioxidants within the human diet as well as physiological stress protectants within the plant. In food chemistry research, a multitude of polyphenols contained in culinary nuts have been studied leading to the identification of their chemical properties and bioactivities. Although functional elucidation of the biosynthetic genes of polyphenols in nut species is crucially important for crop improvement in the creation of higher-quality nuts and stress-tolerant cultivars, the chemical diversity of nut polyphenols and the key biosynthetic genes responsible for their production are still largely uncharacterized. However, current technical advances in whole-genome sequencing have facilitated that nut plant species became model plants for omics-based approaches. Here, we review the chemical diversity of seed polyphenols in majorly consumed nut species coupled to insights into their biological activities. Furthermore, we present an example of the annotation of key genes involved in polyphenolic biosynthesis in peanut using comparative genomics as a case study outlining how we are approaching omics-based approaches of the nut plant species.

Antioxidant and anti-inflammatory effects of Peanut (Arachishypogaea L.) skin extracts of various cultivars in oxidative-damaged HepG2 cells and LPS-induced raw 264.7 macrophages

This study was performed to investigate the distribution of phenolic compounds in the peanut skins of various cultivars, as well as their antioxidant and anti-inflammatory effect (Arachishypogaea L. cv. K-Ol, cv. Sinpalkwang, cv. Daan, cv. Heuksaeng) and extraction solvent. The major components of red peanut cultivars (K-Ol, Sinpalkwang, and Daan) were identified as proanthocyanidin, catechin, gallic acid, coumaric acid, and hesperidine, whereas the major components of black peanut cultivar (Heuksaeng) were identified as anthocyanin, ferulic acid, and quercetin. The DPPH and ABTS radical scavenging activities, and FRAP values were the highest in Daan followed by Sinpalkwng, K-Ol, and Heuksang. Furthermore, the skin extracts of red peanuts effectively improved cell viability, reactive oxygen species generation, MDA concentration, and antioxidant enzyme activity (GR, GPx, CAT, and superoxide dismutase) in oxidative stress-induced HepG2 cells, and reduced the expression of pro-inflammatory factors (NO, TNF-α, IL-6, and IL-1β) in LPS-stimulated RAW 264.7 macrophages. These results suggest that red peanut skin extracts could effectively mediate physiological activity and provide valuable information for the use of peanut byproducts as functional food materials.

Extracts of Peanut Skins as a Source of Bioactive Compounds: Methodology and Applications

Peanut skins are a waste product of the peanut processing industry with little commercial value. They are also significant sources of the polyphenolic compounds that are noted for their bioactivity. The extraction procedures for these compounds range from simple single solvent extracts to sophisticated separation schemes to isolate and identify the large range of compounds present. To take advantage of the bioactivities attributed to the polyphenols present, a range of products both edible and nonedible containing peanut skin extracts have been developed. This review presents the range of studies to date that are dedicated to extracting these compounds from peanut skins and their various applications.

A Glimpse into the Extraction Methods of Active Compounds from Plants

Naturally active compounds are usually contained inside plants and materials thereof. Thus, the extraction of the active compounds from plants needs appropriate extraction methods. The commonly employed extraction methods are mostly based on solid-liquid extraction. Frequently used conventional extraction methods such as maceration, heat-assisted extraction, Soxhlet extraction, and hydrodistillation are often criticized for large solvent consumption and long extraction times. Therefore, many advanced extraction methods incorporating various technologies such as ultrasound, microwaves, high pressure, high voltage, enzyme hydrolysis, innovative solvent systems, adsorption, and mechanical forces have been studied. These advanced extraction methods are often better than conventional methods in terms of higher yields, higher selectivity, lower solvent consumption, shorter processing time, better energy efficiency, and potential to avoid organic solvents. They are usually designed to be greener, more sustainable, and environment friendly. In this review, we have critically described recently developed extraction methods pertaining to obtaining active compounds from plants and materials thereof. Main factors that affect the extraction performances are tuned, and extraction methods are chosen in line with the properties of targeted active compounds or the objectives of extraction. The review also highlights the advancements in extraction procedures by using combinations of extraction methods to obtain high overall yields or high purity extracts.

Natural Antioxidants from Seeds and Their Application in Meat Products

The use of synthetic antioxidants in the food industry has raised important questions about the effects of prolonged consumption on human health. On top of that, the consumption of meat products has been changing due to the awareness generated by health-related organizations. In this sense, exploring strategies to develop and produce healthier meat products has become a paramount concern. Several studies explored the composition of several seeds to characterize and explore the compounds with antioxidant activity, which are mainly composed of polyphenols. The use of antioxidant extracts in meat products has shown important results to delay the oxidative reactions in meat products derived from the processing and storage of meat products. Moreover, these extracts can also replace synthetic antioxidants and preserve the quality of meat products. Therefore, the aims of this review are first, to present the sources and compounds with antioxidant activity in seeds, and second, to discuss their protective effect against oxidative reactions in meat products.

Phenolic Compounds from Nuts: Extraction, Chemical Profiles, and Bioactivity

Nuts contain a vast array of phenolic compounds having important biological properties. They include substances allocated into the five major groups named phenolic acids, flavonoids, tannins, phenolic lignans, and stilbene derivatives. The complexity in composition does not allow for setting a universal extraction procedure suitable for extraction of all nut phenolics. The use of non-conventional extraction techniques, such as those based on microwave, ultrasound, and compressed fluids, combined with generally recognized as safe solvents is gaining major interest. With regard to the latter, ethanol, water, and ethanol-water mixtures have proven to be effective as extracting solvents and allow for clean, safe, and low-cost extraction operations. In recent years, there has been an increasing interest in biological properties of natural phenolic compounds, especially on their role in the prevention of several diseases in which oxidative stress reactions are involved. This review provides an updated and comprehensive overview on nut phenolic extraction and their chemical profiles and bioactive properties.

Optimization of phenolic compounds extraction from Campomanesia lineatifolia leaves

Abstract Campomanesia lineatifolia (gabiroba) is a native edible species found in the Amazon Rainforest. Previous studies have demonstrated the flavonoid nature of ethanolic extract from the C. lineatifolia leaves, in addition to gastroprotective activity and TNF inhibition. However, the extraction process used was long and consumed a large amount of solvent. Therefore, the objective of this study was to obtain a bioactive extract rich in phenolics, in an extractive method of simpler, faster, and lower-cost execution. The C. lineatifolia leaves were dried and crushed, and the extractions were carried out in different solvents/mixtures (ethanol, methanol, ethyl acetate, and water) under ultrasonic bath (UB), electromagnetic stirring, and continuous reflux extraction (R). The extraction efficiency was evaluated by the flavonoid major compound concentration in the extracts, in a method developed by ultra-high performance liquid chromatography (UHPLC). Injection and pattern matching tests, and UHPLC analyses coupled to ultraviolet spectrometry were conducted to identify catechin and quercitrin. It has been demonstrated that the ethanolic extraction by R and the mixture of ethanol: water (8:2) by UB represented optimized methods in obtaining the flavonoid compounds identified. Thus, the results may contribute to chemical-biological extract standardization for gastric antiulcer activity evaluation.

Nutritional profile and nutraceutical components of olive (Olea europaea L.) seeds

Olive seeds, a potential food by-product from both table olive and olive oil industries, were examined for their overall proximate composition, oil, protein, mineral and phenolic components. Proximate analysis indicates that olive seeds are an unusually rich source of total dietary fibre (≅ 47% dry weight basis, DWB), as well as lipids (≅ 30%) and proteins (≅ 17%). Oil composition shows high levels of oleic (≅ 62% of total fatty acids) and linoleic (≅ 24%) acids, moderate concentrations of tocopherols (≅ 460 mg/kg) and squalene (≅ 194 mg/kg), and relatively high amounts of several sterols and non-steroidal triterpenoids. Olive seed proteins are a rich source of essential amino acids (about 46% of the total AA content). Olive seeds also contain significant amounts of some essential macro-elements (K, Ca, Mg, Na, P) and micro-elements (Zn, Mn, Cu). Phenolic compounds are present at relatively high quantities (≅ 2.8 mg/g seed, DWB); the most abundant belong to the group of secoiridoid compounds (elenolic acid derivatives) including oleuropein and structurally related substances (demethyloleuropein and ligstroside), and nüzhenide derivatives. Based on the general nutritional profile and nutraceutical components, olive seeds have value-added potential as a source of edible oil, proteins or meal serving as feed supplements.

Subcritical Fluid Extraction of Antioxidant Phenolic Compounds from Pistachio (Pistacia vera L.) Nuts: Experiments, Modeling, and Optimization

A process to obtain phenolic compounds with antioxidant properties from pistachio nuts using water/ethanol mixture under high temperature and pressure conditions was carried out. To optimize extraction conditions and antioxidant activity of bioactive compounds, theoretical models were scanned against experimental data. Phenolic profile was dominated by several flavonoids and gallic acid derivatives. A fitted model for phenolic compounds extraction presented a maximum predicted value under the following conditions: 220 °C extraction temperature, 6.5 MPa pressure, and 50% ethanol. Beneath these conditions, phenolic extracts gave the highest radical scavenging capacity, similar to that reached by using commercial antioxidants. A mathematical model, namely two-site desorption kinetic model, showed to be suitable for the description of extraction kinetics under the optimal operation conditions. Overall, the process described in this study shows a potential alternative method for extraction of pistachio bioactive compounds. PRACTICAL APPLICATION: Pistachio nuts are known to contain a vast array of phenolic and polyphenolic substances having strong antioxidant properties. Currently, the use of natural antioxidants in the food industry has increased, in consequence there is a growing interest in improving the extraction processes using GRAS (general recognize as safe) solvents. This study describes a safe, inexpensive, and short-time method (subcritical fluid extraction) to obtain antioxidant extracts from defatted pistachio nuts. This type of process may be adapted toward applications at industrial scale.