Liquid chromatography-mass spectrometry coupled with multivariate analysis for the characterization and discrimination of extractable and nonextractable polyphenols and glucosinolates from red cabbage and Brussels sprout waste streams

Bioaccessibility and unravelling of polyphenols, sulforaphane, and indoles biotransformation after in vitro gastrointestinal digestion of a novel lactofermented broccoli beverage

This study assesses the transformation and stability of polyphenols, sulforaphane, and indoles in a fermented beverage made from broccoli leaves during in vitro gastrointestinal digestion (GID). This process was simulated using a dialysis membrane to assess intestinal absorption. The total phenolic compounds (TPC) and antioxidant TEAC assays showed an increase in phytochemical content due to the GID process. The higher TPC and antioxidant activity observed after digestion was likely due to the enzymatic transformation of polyphenols in mildly alkaline conditions. Individual phytochemical analysis revealed that hydroxycinnamic acids, particularly 3CQa, remained stable initially but then decreased significantly during intestinal digestion. Acylated flavonoids exhibited a decrease during intestinal digestion, while deacylated flavonoids initially decreased before stabilising. This indicated the occurrence of enzymatic hydrolysis of more structurally complex flavonoids to glycosylated flavonoids such as kaempferol-3,7-diglucoside, and kaempferol-3-sophoroside-7-glucoside. Consequently, deacylated flavonoids were highlighted for their high bioaccessibility rate after in vitro GID. Glucosinolate-hydrolysis products, including sulforaphane and indoles, exhibited a general decrease during digestion, with sulforaphane showing 51% bioaccessibility. The study highlights the dialysed in vitro GID process, which affects the release and transformation of bioactive compounds, potentially increasing their bioaccessibility and the subsequent health benefits of the lactofermented beverage made from broccoli leaves.

Evaluation of smart bi-functional dressing based on polysaccharide hydrogels and Brassica oleracea extract for wound healing and continuous monitoring

Skin wounds can drive global impacts, socially and economically, in parallel with their elevated incidence rate. Therefore, utilizing the dual-activity of Brassica Oleracea (Red Cabbage) extract, of being pH-sensitive and biologically active in designing novel, therapeutic, and pH-sensitive wound dressings with an easily stripped-off feature, is critical. Wound dressings were designed using two separate hydrogels based on chitosan (CS) and hydroxyethylcellulose (HEC), each loaded with RCE. The pH sensitivity of prepared bandages exhibited a noticeable visual change in color during wound treatment. Wound closure has reached 99.69 % for CS/RCE dressings. Results showed that RCE had raised the hydroxyproline and collagen content in the healed skin. Histopathological investigation proves that skin returned to its regular thickness within 10 days of treatment. RCE showed marked improvement in the healing quality by acting as an antioxidant, anti-inflammatory, and antimicrobial agent. Therefore, dual-function dressings are potential candidates to sense and cure skin wounds.

The potential of Acmella oleracea as a nutraceutical source for the symptomatic treatment of Burning Mouth Syndrome

This study analysed the phytochemical profile of Acmella oleracea extract and the molecular interactions of its main compounds with TRPV1 and CB2, target receptors in the Burning Mouth Syndrome (BMS) pathogenesis. The phytochemical profile of A. oleracea's floral buds extract treated with activated charcoal (TCEE) was analysed by High-Performance Liquid Chromatography (HPLC) coupled to Mass Spectrometry (LC-MS). The quantification of spilanthol was analysed by HPLC coupled to a Diode-Array Detector (HPLC-DAD). The phytochemical analysis revealed the presence of nine alkylamides and phenolic compounds. The TCEE showed a significant increase in spilanthol content compared to the crude extract (CEE), going from 28.33 mg/g to 117.96 mg/g. The molecular docking indicated a behaviour of the alkylamides as partial TRPV1 agonists and CB2 agonists and, for the first time, indicates the action of these compounds in the symptomatic management of BMS.

Optimization of phenolic compounds extraction from olive mill wastewater using response surface methodology

Large amounts of pomace are produced during the extraction of olive oil. This is because only 21% of an olive's weight is made up of oil, while 79% includes water, bark and pulp. This project extracted total phenolic compounds (TPCs) from olive mill wastewater as efficiently as possible. The TPCs were analyzed and the total antioxidant activity (TAA) was evaluated by spectrophotometry. Data were evaluated using the response surface method (RSM). The largest TAA and TPC were discovered in extracting using 80% ethanol at 25 °C, and 2.5 bar with pH = 4. The highest amount of TPCs was 11.614 mg of gallic acid per 100 mL, and a value of 71.06% was reported for TAA. The results of the quadratic model showed that R2 is equal to 0.937, because it has a larger coefficient and the pH factor had the least effect. The temperature factor had the greatest impact on the extraction of TPC and TAA, and the mutual temperature and pH impacts affected the extraction positively. As a result, it can be concluded that the RSM was a useful tool for assessing the ideal circumstances for phenolic component extraction.

Interaction between Dietary Fibre and Bioactive Compounds in Plant By-Products: Impact on Bioaccessibility and Bioavailability

In Europe, around 31 million tonnes of food by-products are generated during primary production and trade. The management of these by-products may cause a negative impact, both at the economic and environmental levels, for both industry and society. In this regard, taking into consideration that these by-products retain the dietary fibre compositions and the bioactive compounds of the starting materials, plant food agro-industries have an interest in taking advantage of them, from a nutritional point of view. Therefore, this review evaluates the role of dietary fibre and bioactive compounds in these by-products as well as the potential interactions of both components and their implications for health, since the bioactive compounds associated with fibre may reach the colon, where they can be metabolised into postbiotic compounds, providing important health benefits (prebiotic, antioxidant, anti-inflammatory, etc.). Consequently, this aspect, on which there are few studies, is very relevant and must be considered in the revaluation of by-products to obtain new ingredients for food processing with improved nutritional and technological properties.

By-Products of Fruit and Vegetables: Antioxidant Properties of Extractable and Non-Extractable Phenolic Compounds

Non-extractable phenolic compounds (NEPs), or bound phenolic compounds, represent a crucial component of polyphenols. They are an essential fraction that remains in the residual matrix after the extraction of extractable phenolic compounds (EPs), making them a valuable resource for numerous applications. These compounds encompass a diverse range of phenolic compounds, ranging from low molecular weight phenolic to high polymeric polyphenols attached to other macro molecules, e.g., cell walls and proteins. Their status as natural, green antioxidants have been well established, with numerous studies showcasing their anti-inflammatory, anti-aging, anti-cancer, and hypoglycemic activities. These properties make them a highly desirable alternative to synthetic antioxidants. Fruit and vegetable (F&Veg) wastes, e.g., peels, pomace, and seeds, generated during the harvest, transport, and processing of F&Vegs, are abundant in NEPs and EPs. This review delves into the various types, contents, structures, and antioxidant activities of NEPs and EPs in F&Veg wastes. The relationship between the structure of these compounds and their antioxidant activity is explored in detail, highlighting the importance of structure-activity relationships in the field of natural antioxidants. Their potential applications ranging from functional food and beverage products to nutraceutical and cosmetic products. A glimpse into their bright future as a valuable resource for a greener, healthier, and more sustainable future, and calling for researchers, industrialists, and policymakers to explore their full potential, are elaborated.

Salivary flow and turbidity development inconsistently associated with lower taste intensity of vegetables and juices

The same phytochemicals that stimulate aversive sensations are often also responsible for purported health benefits in fruits and vegetables. Prior work indicates that some salivary proteins may reduce aversiveness of phytochemicals. In rodents, the salivary binding proteins have been shown to reduce bitter taste of polyphenols and alkaloids, but work in humans has focused primarily on polyphenol astringency (dry, rough, or puckery sensations). In this study, we tested if tastes of vegetable products might correlate to either salivary flow rate or the polyphenol binding capability of saliva, as measured by turbidity development when saliva is mixed with tannic acid. Participants (N=26) provided chewing-stimulated saliva samples and rated five juices and two chopped vegetables for bitterness, sourness, and sweetness intensity. Saliva was mixed with tannic acid and light absorbance was measured for quantification of haze development. Greater absorbance corresponded to less bitterness for one green vegetable juice blend, less sweetness for two green vegetable juices and chopped kale, and less sourness from cranberry juice. Greater salivary flow corresponded to less bitterness from chopped brussels sprouts, and less sweetness from one green vegetable juice blend and chopped kale. These findings indicate that greater salivary flow rate and presence of certain salivary binding proteins is not universally associated with lower aversive tastes from phytochemical-containing foods. Whether associations between these salivary properties are ingredient specific or simply not robustly related to taste in commercial products should be further investigated.

Dietary-Fibre-Rich Fractions Isolated from Broccoli Stalks as a Potential Functional Ingredient with Phenolic Compounds and Glucosinolates

The Brassica oleracea industry generates large amounts of by-products to which value could be added because of the characteristics of their composition. The aim was to extract different fibre fractions from broccoli stalks to obtain potential new added-value ingredients. Using an ethanol and water extraction procedure, two fibre-rich fractions (total fibre fraction, TF_B, and insoluble fibre fraction, IF_B) were obtained. These fractions were analysed to determine the nutritional, (poly)phenols and glucosinolates composition and physicochemical properties, comparing the results with those of freeze-dried broccoli stalks (DBS). Although TF_B showed a higher content of total dietary fibre, IF_B had the same content of insoluble dietary fibre as TF_B (54%), better hydration properties, higher content of glucosinolates (100 mg/100 g d.w.) and (poly)phenols (74.7 mg/100 g d.w.). The prebiotic effect was evaluated in IF_B and compared with DBS by in vitro fermentation with human faecal slurries. After 48 h, the short-chain fatty acid (SCFA) production was higher with IF_B than with DBS because of the greater presence of both uronic acids, the main component of pectin, and (poly)phenols. These results reveal that novel fibre-rich ingredients—with antioxidant, technological and physiological effects—could be obtained from broccoli stalks by using green extraction methods.

Valorization of Food Processing Waste to Produce Valuable Polyphenolics

Traditional incineration and landfill of food processing waste (FPW) have polluted the environment and underutilized valuable bioactive compounds, including polyphenols in food waste. As one of the most widely occurring compounds in the FPW, polyphenols possess high utilization value in many fields such as human health, energy, and environmental protection. Extracting polyphenols directly from FPW can maximize the value of polyphenols and avoid waste of resources. However, traditional polyphenol extraction methods mostly use the Soxhlet extraction, infiltration, and impregnation method, consuming a large amount of organic solvent and suffering from long extraction time and low extraction efficiency. Emerging green extraction methods such as supercritical fluid extraction, ultrasonic-assisted extraction, microwave-assisted extraction, and other methods can shorten the extraction time and improve the solvent extraction efficacy, resulting in the green and safe recovery of polyphenols from FPW. In this paper, the traditional treatment methods of FPW waste and the application of polyphenols in FPW are briefly reviewed, and the traditional extraction methods and emerging green extraction methods of polyphenols in FPW are compared to obtain insight into the start-of-the-art extraction approaches.

Phenolic and Volatile Composition and Antioxidant Properties of the Leaf Extract of Brassica fruticulosa subsp. fruticulosa (Brassicaceae) Growing Wild in Sicily (Italy)

In continuation of research conducted on species of the spontaneous flora of Sicily (Italy) belonging to the Brassicaceae family, Brassica fruticulosa subsp. fruticulosa was selected. It is an edible species utilized in Sicilian traditional medicine. In this study, for the first time, the phenolic and the volatile compounds and the antioxidant properties of the hydroalcoholic extract obtained from the leaves of B. fruticulosa subsp. fruticulosa were characterized. Through HPLC-PDA/ESI-MS analysis, a total of 22 polyphenolic compounds (20 flavonoids and 2 phenolic acids) were identified, with 3-hydroxiferuloylsophoroside-7-O-glucoside (1.30 mg/g ± 0.01) and kaempferol-3-O-feruloylsophoroside-7-O-glucoside (1.28 mg/g ± 0.01) as the most abundant compounds. Through SPME-GC/MS several volatiles belonging to different chemical classes were characterized, with nitriles and aldehydes accounting for more than 54% of the whole volatile fraction. The extract of B. fruticulosa subsp. fruticulosa showed moderate activity in the DPPH assay (IC50 = 1.65 ± 0.08 mg/mL), weak reducing power (17.47 ± 0.65 ASE/mL), and good chelating properties (IC50 = 0.38 ± 0.02 mg/mL), reaching approximately 90% activity at the highest tested concentration. Lastly, the extract was non-toxic against Artemia salina, indicating its potential safety. According to the findings, it can be stated that B. fruticulosa subsp. fruticulosa represents a new valuable source of bioactive compounds.

Influence of the extraction method on the recovery of bioactive phenolic compounds from food industry by-products

Agro-foodindustries generate colossal amounts of non-edible waste and by-products, easily accessible as raw materials for up-cycling active phytochemicals. Phenolic compounds are particularly relevant in this field given their abundance in plant residues and the market interest of their functionalities (e.g. natural antioxidant activity) as part of nutraceutical, cosmetological and biomedical formulations. In "bench-to-bedside" achievements, sample extraction is essential because valorization benefits from matrix desorption and solubilization of targeted phytocompounds. Specifically, the composition and polarity of the extractant, the optimal sample particle size and sample:solvent ratio, as well as pH, pressure and temperature are strategic for the release and stability of mobilized species. On the other hand, current green chemistry environmental rules require extraction approaches that eliminate polluting consumables and reduce energy needs. Thus, the following pages provide an update on advanced technologies for the sustainable and efficient recovery of phenolics from plant matrices.

Bioactive Compounds from Agricultural Residues, Their Obtaining Techniques, and the Antimicrobial Effect as Postharvest Additives

Agricultural vegetable products always seek to meet the growing demands of the population; however, today, there are great losses in supply chains and in the sales stage. Looking for a longer shelf life of fruits and vegetables, postharvest technologies have been developed that allow an adequate transfer from the field to the point of sale and a longer shelf life. One of the most attractive methods to improve quality and nutritional content and extend shelf life of fruits and vegetables is the incorporation of bioactive compounds with postharvest technologies. These compounds are substances that can prevent food spoilage and the proliferation of harmful microorganisms and, in some cases, act as a dietary supplement or provide health benefits. This review presents an updated overview of the knowledge about bioactive compounds derived from plant residues, the techniques most used for obtaining them, their incorporation in edible films and coatings, and the methods of microbial inhibition.

A Review of the Health Protective Effects of Phenolic Acids against a Range of Severe Pathologic Conditions (Including Coronavirus-Based Infections)

Phenolic acids comprise a class of phytochemical compounds that can be extracted from various plant sources and are well known for their antioxidant and anti-inflammatory properties. A few of the most common naturally occurring phenolic acids (i.e., caffeic, carnosic, ferulic, gallic, p-coumaric, rosmarinic, vanillic) have been identified as ingredients of edible botanicals (thyme, oregano, rosemary, sage, mint, etc.). Over the last decade, clinical research has focused on a number of in vitro (in human cells) and in vivo (animal) studies aimed at exploring the health protective effects of phenolic acids against the most severe human diseases. In this review paper, the authors first report on the main structural features of phenolic acids, their most important natural sources and their extraction techniques. Subsequently, the main target of this analysis is to provide an overview of the most recent clinical studies on phenolic acids that investigate their health effects against a range of severe pathologic conditions (e.g., cancer, cardiovascular diseases, hepatotoxicity, neurotoxicity, and viral infections—including coronaviruses-based ones).

Comprehensive Evaluation of Amino Acids and Polyphenols in 69 Varieties of Green Cabbage (Brassica oleracea L. var. capitata L.) Based on Multivariate Statistical Analysis

The biological activities of the primary metabolites and secondary metabolites of 69 green cabbage varieties were tested. The LC-MS detection method was used to determine the content of 19 free amino acids (lysine, tryptophan, phenylalanine, methionine, threonine, isoleucine, leucine, valine, arginine, asparagine, glycine, proline, tyrosine, glutamine, alanine, aspartic acid, serine, and glutamate). The content of 10 polyphenols (chlorogenic acid, gallic acid, 4-coumaric acid, ferulic acid, gentisic acid, cymarin, erucic acid, benzoic acid, rutin, and kaempferol) was determined by the HPLC detection method. Considering the complexity of the data obtained, variance analysis, diversity analysis, correlation analysis, hierarchical cluster analysis (HCA), and principal component analysis (PCA) were used to process and correlate amino acid or polyphenol data, respectively. The results showed that there were significant differences between the different amino acids and polyphenols of the 69 cabbage varieties. The most abundant amino acids and polyphenols were Glu and rutin, respectively. Both amino acids and polyphenols had a high genetic diversity, and multiple groups of significant or extremely significant correlations. The 69 cabbage varieties were divided into two groups, according to 19 amino acid indexes, by PCA. Among them, seven varieties with high amino acid content all fell into the fourth quadrant. The HCA of amino acids also supports this view. Based on 10 polyphenols, the 69 cabbage varieties were divided into two groups by HCA. Based on 29 indexes of amino acids and polyphenols, 69 cabbage varieties were evaluated and ranked by PCA. Therefore, in this study, cabbage varieties were classified in accordance with the level of amino acids and polyphenols, which provided a theoretical basis for the genetic improvement of nutritional quality in cabbage.

UHPLC-ESI-QTOF-MS/MS Metabolite Profiling of the Antioxidant and Antidiabetic Activities of Red Cabbage and Broccoli Seeds and Sprouts

The antioxidant and antidiabetic properties and metabolite profiling of ethanol extracts of red cabbage (RC) and broccoli (BR) seeds and sprouts were investigated in this study. The total phenolic, flavonoid, and saponin contents were in the ranges of 385.4-480.4 mg FAE/100 g, 206.9-215.6 mg CE/100 g, and 17.8-27.0 mg soysaponin BE/100 g, respectively. BR seed had the highest total phenolic (480.4 mg FAE/100 g) and flavonoid (216.9 mg CE/100 g) contents, whereas BR sprout had the highest saponin content (27.0 soysaponin BE/100g). RC sprout demonstrated the highest antioxidant capacity, with DPPH and ABTS radical scavenging activity levels of 71.5% and 88.5%, respectively. Furthermore, BR and RC sprouts showed the most potent inhibition against α-glucosidase (91.32% and 93.11%, respectively) and pancreatic lipase (60.19% and 61.66%, respectively). BR seed (60.37%) demonstrated the lowest AGE inhibition. A total of 24 metabolites, predominantly amino acids and phenolic compounds, were characterized using UHPLC-QTOF-MS/MS. Germination not only improved the levels of metabolites but also resulted in the synthesis of new compounds. Therefore, these findings show that germination effectively enhanced the functional properties and metabolite profiles of broccoli and red cabbage seeds, making their sprouts more applicable as functional ingredients.

Screening of Indian bee pollen based on antioxidant properties and polyphenolic composition using UHPLC-DAD-MS/MS: A multivariate analysis and ANN based approach

The present investigation aims to examine the polyphenolic composition and antioxidant capacity of bee pollen samples procured from various regions of India. Total phenolic (TPC) and flavonoid (TFC) content ranged from 15.50 ± 1.25-25.63 ± 1.42 mg GAE/g and 9.72 ± 0.28-15.61 ± 0.74 mg RE/g, respectively. Coriander pollen showed the significantly (p < 0.05) higher antioxidant activity than other samples, demonstrated by DPPH radical scavenging activity (93.75 ± 0.05%), ferric reducing antioxidant power (103.98 ± 0.82 mmol Fe²⁺/g), ABTS^+• radical scavenging activity (96.58 ± 0.65%) and metal chelating activity (84.62 ± 4.37%). The observed antioxidant properties were strongly correlated with TPC and effectively predicted using artificial neural network. Sixty polyphenolic compounds including 38 flavonoids and derivatives, 21 phenolic acid and derivatives and one glucosinolates were identified using UHPLC-DAD-MS/MS wherein the presence of daidzein and sinigrin was acknowledged for the first time. Further, principal component analysis identified three principal components, illustrating 91.24% of total variation to differentiate the pollen samples which were also classified by hierarchical cluster analysis.

Phytochemical Profile and Antioxidant Activity of Aerial and Underground Parts of Salvia bulleyana Diels. Plants

Plants have been used for medical purposes since ancient times. However, a detailed analysis of their biological properties and their associated active compounds is needed to justify their therapeutic use in modern medicine. The aim of the study was to identify and quantify the phenolics present in hydromethanolic extracts of the roots and shoots of the Chinese Salvia species, Salvia bulleyana. The qualitative and quantitative analyses were carried out by ultrahigh-performance liquid chromatography with electrospray ionization mass spectrometry detection (UHPLC-PDA-ESI-MS), and high-performance liquid chromatography with photodiode array (HPLC-PDA) detection. The extracts of S. bulleyana were also screened for their antioxidant activity using ferric ion (Fe³⁺) reducing antioxidant power (FRAP), 1,1-diphenyl-2-picrylhydrazyl (DPPH), diammonium 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) cation (ABTS), superoxide radical anion (O₂•–), and inhibition of lipid peroxidation assays. The S. bulleyana extracts were found to contain 38 substances, of which 36 were phenols, with a total level of 14.4 mg/g DW (dry weight) in shoots, and 23.1 mg/g DW in roots. Twenty-eight phenols were polyphenolic acids or their derivatives, the most abundant in shoots being rosmarinic acid, and in roots, salvianolic acid K followed by rosmarinic acid. The other major phenolic acids were caffeic acid, caffeoyl-threonic acids, isomers of lithospermic acid, salvianolic acid F, salvianolic acid B, and yunnaneic acid E. In addition to polyphenolic acids, nine flavonoids were detected in the shoot extract. While both extracts showed significant antioxidant activity, the shoot extract, containing both polyphenolic acids and flavonoids, demonstrated a slightly greater antioxidant potential in some of the anti-radical tests than the roots. However, the root extract proved to be slightly more effective in the lipid peroxidation inhibition test. Thus, S. bulleyana was demonstrated as a promising source of antioxidants, and worthy of further more detailed studies.

Functional changes induced by extrusion during cocoa alkalization

Polyphenols, a group of secondary metabolites, have well-known relevant effects on human health. During traditional alkalization, this content dramatically lowers. We aimed to evaluate an alternative alkalization method based on extrusion on cocoa functional characteristics. The results showed that the antioxidant capacity and total phenolic values increased as alkali concentration and temperature did, and these values doubled under less extreme conditions. Comparing the functional properties between extruded and traditionally produced powders revealed that catechin, epicatechin and dimers B1 and B2 contents were 43%, 33%, 54% and 34% lower in the extruded samples, respectively. However, this reduction was partially balanced by increased clovamide content up to 50%. Thus the total phenol content and antioxidant capacity of the extruded samples were statistically above those of the commercial one. Hence extrusion alkalization should be considered a new processing alternative to avoid markedly reducing functional properties.

Non-Extractable Polyphenols from Food By-Products: Current Knowledge on Recovery, Characterisation, and Potential Applications

Non-extractable polyphenols (NEPs), or bound polyphenols, are a significant fraction of polyphenols that are retained in the extraction residues after conventional aqueous organic solvent extraction. They include both high molecular weight polymeric polyphenols and low molecular weight phenolics attached to macromolecules. Current knowledge proved that these bioactive compounds possess high antioxidant, antidiabetic, and other biological activities. Plant-based food by-products, such as peels, pomace, and seeds, possess high amount of NEPs. The recovery of these valuable compounds is considered an effective way to recycle food by-products and mitigate pollution, bad manufacturing practice, and economic loss caused by the residues management. The current challenge to valorise NEPs from plant-based by-products is to increase the extraction efficiency with proper techniques, choose appropriate characterising methods, and explore potential functions to use in some products. Based on this scenario, the present review aims to summarise the extraction procedure and technologies applied to recover NEPs from plant-based by-products. Furthermore, it also describes the main techniques used for the characterisation of NEPs and outlines their potential food, pharmaceutical, nutraceutical, and cosmetic applications.

Bioactive Phenolic Compounds From Agri-Food Wastes: An Update on Green and Sustainable Extraction Methodologies

Phenolic compounds are broadly represented in plant kingdom, and their occurrence in easily accessible low-cost sources like wastes from agri-food processing have led in the last decade to an increase of interest in their recovery and further exploitation. Indeed, most of these compounds are endowed with beneficial properties to human health (e.g., in the prevention of cancer and cardiovascular diseases), that may be largely ascribed to their potent antioxidant and scavenging activity against reactive oxygen species generated in settings of oxidative stress and responsible for the onset of several inflammatory and degenerative diseases. Apart from their use as food supplements or as additives in functional foods, natural phenolic compounds have become increasingly attractive also from a technological point of view, due to their possible exploitation in materials science. Several extraction methodologies have been reported for the recovery of phenolic compounds from agri-food wastes mostly based on the use of organic solvents such as methanol, ethanol, or acetone. However, there is an increasing need for green and sustainable approaches leading to phenolic-rich extracts with low environmental impact. This review addresses the most promising and innovative methodologies for the recovery of functional phenolic compounds from waste materials that have appeared in the recent literature. In particular, extraction procedures based on the use of green technologies (supercritical fluid, microwaves, ultrasounds) as well as of green solvents such as deep eutectic solvents (DES) are surveyed.

Novel pH-sensitive alginate hydrogel delivery system reinforced with gum tragacanth for intestinal targeting of nutraceuticals

The present study utilizes the novel combination of Gum tragacanth (GT) and sodium alginate (SA) to reinforce SA hydrogel beads. The composite hydrogel beads were encapsulated with phenolic compounds extracted from Basella sps. The rheological studies conferred increased elastic property of GT incorporated formulations. Higher swelling behavior was observed in simulated intestinal fluid (SIF) with increasing GT content in SA formulations. SA-GT composite hydrogels revealed increased encapsulation efficiency with sustained release of phenolic compounds in SIF. GT incorporated hydrogel beads exhibited increased biodegradation (up to 82% weight loss) in biodegradation media (in vitro). FTIR study found no molecular interaction between SA and GT. TGA analysis revealed that GT incorporation did not affect the thermal behavior of SA. Furthermore, SA-GT encapsulated hydrogels showed remarkable cytotoxicity against osteosarcoma cells. Thus our findings suggest SA-GT gel formulation could be used as a promising delivery system for drugs and nutraceutical compounds.

Comprehensive identification and quantification of unexploited phenolic compounds from red and yellow araçá (Psidium cattleianum Sabine) by LC-DAD-ESI-MS/MS

LC-DAD-ESI-MS/MS was used to comprehensively characterise the non-extractable phenolic compounds (NEPC) in red and yellow araçá genotypes. Results showed a total of 45 and 43 phenolic compounds in the NEPC fraction and, similarly, 51 and 50 compounds in extractable phenolic compounds (EPC) fraction from red and yellow araçá, respectively. Gallic acid and ellagic acid were the unique compounds found in both fractions. The NEPC fraction represented about 35% (m/m) of the total phenolic content and was characterised by an abundance of phenolic acids, while the EPC fraction was rich in flavanols. Although NEPC represented one-third of the total phenolic compounds found in araçá, its antioxidant capacity (against peroxyl radical) was 50% higher than the EPC fraction. The results of this work show that the NEPC fraction of araçá has great diversity and a relatively high concentration of low-molecular-weight phenolic compounds with high antioxidant capacity.

Multivariate Analysis Illuminates the Effects of Vacuum Drying on the Extractable and Nonextractable Polyphenols Profile of Loquat Fruit

The current study evaluated the effects of vacuum drying on the whole polyphenol profile of loquat fruit, including extractive and nonextractive polyphenols. Absorbance analysis determined that total polyphenol content and antioxidant levels were higher in loquat fruit vacuum dried at 140 °C than in loquat fruit vacuum dried at 70 °C. The results of ultra-HPLC-triple quadruple mass spectrum analysis showed that 15 phenolic acids and 17 flavonoids were found in dried loquat fruit. Multivariate integrative (MINT) sparse partial least square-discriminant analysis showed that vacuum drying affects the polyphenol profile of loquat fruit. Co-analysis of principal component analysis, partial least square-discriminant analysis, and orthometric partial least square-discriminant analysis revealed that vacuum drying mainly changed the content of chlorogenic acid, cryptochlorogenic acid, protocatechuic acid, phloretin, and hesperidin in loquat fruit. Chlorogenic acid (12.020 to 39.153 µg/g d.b. [dried base weight]), the main polyphenol in dried loquat fruit, was degraded to caffeic acid (0.028 to 2.365 µg/g d.b.) and protocatechuic acid (0.014 to 18.285 µg/g d.b.) during vacuum drying. Moreover, vacuum drying also induced the isomerization of chlorogenic acid into cryptochlorogenic acid (1.628 to 12.737 µg/g d.b.). These results might be used to develop dried loquat fruit with high levels of polyphenols and antioxidant activity. PRACTICAL APPLICATION: Interests in polyphenols of loquat fruit had increased greatly because of their possible role in health benefits. This work provided a holistic insight in the effects of vacuum drying on polyphenols profile of loquat fruit. Current results have contributed to the development of vacuum-drying method, which produced loquat fruit rich in polyphenols. Furthermore, it also suggested that multivariate analysis was a feasible method to reveal the important changes of polyphenols profile during food processing.

Opuntia (Cactaceae) plant compounds, biological activities and prospects - A comprehensive review

Opuntia species are utilized as local medicinal interventions for chronic diseases and as food sources mainly because they possess nutritional properties and biological activities. The Opuntia plant is distributed worldwide and has great economic potential. Differences in Opuntia species phytochemical composition exist between wild and domesticated species, and within species. Opuntia aerial and underground parts exhibit beneficial properties due to their phenolic content, other antioxidants (for example ascorbate), pigments (carotenoids, betalains), and other unidentified components. This work comprehensively reviews the phytochemical composition of the different aerial and underground plant parts of Opuntia species. The applications of Opuntia compounds and their biological activities are also discussed. Other topical aspects covered include Opuntia spp. taurine composition, Opuntia side effects, Opuntia by-products valorisation and the role of Opuntia spp. in tackling antimicrobial resistance. Although biological activities have been extensively researched, much less information is available on reaction mechanisms, herbal mixtures toxicology and commercialisation prospects - aspects which should be considered for future research in this area.

Fruit peels as sources of non-extractable polyphenols or macromolecular antioxidants: Analysis and nutritional implications

Despite increasing interest in the relevance of non-extractable polyphenols (NEPP) or macromolecular antioxidants as food bioactive compounds, most studies on their presence in foods focus mainly on the edible part of specific fruits, but their potential presence in fruit peels is usually ignored. The aim of this study was to evaluate NEPP content in the peels from ten common fruits. The results showed that NEPP made up more than half of the total polyphenol contents in half of the studied samples. HPLC analysis showed that NEPP were constituted by phenolic acids, flavanols and flavonols. Also, it was found that peels accounted for >40% of total NEPP in the fruit in four of the samples analysed. These results should encourage both the use of fruit peels in the fruit industry as ingredients and the consumption of whole fruits given the significant presence of NEPP in fruit peels.

Liquid chromatography-high resolution mass spectrometry for the analysis of phytochemicals in vegetal-derived food and beverages

The recent years witnessed a change in the perception of nutrition. Diet does not only provide nutrients to meet the metabolic requirements of the body, but it also constitutes an active way for the consumption of compounds beneficial for human health. Fruit and vegetables are an excellent source of such compounds, thus the growing interest in characterizing phytochemical sources, structures and activities. Given the interest for phytochemicals in food, the development of advanced and suitable analytical techniques for their identification is fundamental for the advancement of food research. In this review, the state of the art of phytochemical research in food plants is described, starting from sample preparation, throughout extract clean-up and compound separation techniques, to the final analysis, considering both qualitative and quantitative investigations. In this regard, from an analytical point of view, fruit and vegetable extracts are complex matrices, which greatly benefit from the use of modern hyphenated techniques, in particular from the combination of high performance liquid chromatography separation and high resolution mass spectrometry, powerful tools which are being increasingly used in the recent years. Therefore, selected applications to real samples are presented and discussed, in particular for the analysis of phenols, polyphenols and phenolic acids. Finally, some hot points are discussed, such as waste characterization for high value-compounds recovery and the untargeted metabolomics approach.

Strategies for the extraction and analysis of non-extractable polyphenols from plants

The majority of studies based on phenolic compounds from plants are focused on the extractable fraction derived from an aqueous or aqueous-organic extraction. However, an important fraction of polyphenols is ignored due to the fact that they remain retained in the residue of extraction. They are the so-called non-extractable polyphenols (NEPs) which are high molecular weight polymeric polyphenols or individual low molecular weight phenolics associated to macromolecules. The scarce information available about NEPs shows that these compounds possess interesting biological activities. That is why the interest about the study of these compounds has been increasing in the last years. Furthermore, the extraction and characterization of NEPs are considered a challenge because the developed analytical methodologies present some limitations. Thus, the present literature review summarizes current knowledge of NEPs and the different methodologies for the extraction of these compounds, with a particular focus on hydrolysis treatments. Besides, this review provides information on the most recent developments in the purification, separation, identification and quantification of NEPs from plants.

Study Approach of Antioxidant Properties in Foods: Update and Considerations

The assessment of interactions between natural antioxidants and other food matrix components represents the main step in the investigation of total antioxidant properties, in terms of potential health benefits. The diversity of chemical structures of natural compounds, besides their possible interactions, as well as the biological role and different modes of action makes it difficult to assess a single and reliable procedure for the evaluation of antioxidant activity. Today, much attention is given to the distinction between extractable and non-extractable antioxidants as a key tool in the description of the nutritional and healthy properties of food matrices. The starting point for the investigation of antioxidant effects of food extracts is the analysis of antioxidant properties of pure compounds and their interactions. Another complementary approach could be represented by the study of how different biologically active compound-rich extracts contribute to the total antioxidant capacity.

Brussels Sprout Decapitation Yields Larger Sprouts of Superior Quality

A common technological practice in Brussels sprouts (Brassica oleracea L. var. gemmifera) production is the removal of apical plant section a few weeks before harvest in order to promote the development of auxiliary buds (sprouts) and ensure higher yields. It is well-known that this measure positively influences the size of the sprouts, but until now no study has focused on the effect of decapitation on the content of primary and secondary metabolites in Brussels sprouts. Plants were decapitated one month before harvest, and sprouts were sampled from three sections along the stem (basal, middle, top) of each plant. The sprouts were harvested, weighed, and chemically analyzed. The content of individual sugars was assessed by HPLC and the content of individual phenolics and glucosinolates by HPLC-MS. Significant interactions between the decapitation and different stem sections were detected in the weight of the sprouts, as well as in their sugar levels. The highest sugar content was determined in basal sprouts collected from decapitated plants. Conversely, basal sprouts from nondecapitated plants were characterized by the lowest sugar content. No interaction between the decapitation and stem sections was detected in the level of phenolics or glucosinolates. Decapitation promoted the accumulation of all glucosinolates and hydroxycinnamic acids. Moreover, the content of glucosinolates and flavonoids was always highest in the sprouts from the top stem section.

Characterization of Polyphenols from Lycium ruthenicum Fruit by UPLC-Q-TOF/MS(E) and Their Antioxidant Activity in Caco-2 Cells

The fruit of Lycium ruthenicum Murr. (LRF) has long been used in folk medicine. Nevertheless, detailed information related to its polyphenol compositions remains scarce. In this study, we confirmed that the total phenolic and anthocyanin contents of LRF fruit extracts (LRFEs) were 4906.5 ± 60.6 mg of gallic acid equivalents/100 g DW and 787.6 ± 34.1 mg of cyanindin-3-glucoside equivalents/100 g DW, respectively. A characterization of LRFEs was performed by ultrahigh performance liquid chromatography/quadrupole time-of-flight mass spectrometry using an MS(E) data acquisition. A total of 26 polyphenols were tentatively identified, of which 19 represent the first reports of these polyphenols in LRFEs. Furthermore, the cellular antioxidant array showed that LRFEs could protect Caco-2 cells against H2O2-induced oxidative damage based on microscopic fluorometric imaging.