Optimization of drying process and pressurized liquid extraction for recovery of bioactive compounds from avocado peel by-product

Pressurized liquid extraction of glucosinolates from Camelina sativa (L.) Crantz by-products: Process optimization and biological activities of green extract

The cultivation of Camelina sativa (L.) Crantz is rapidly increasing due to oil production resulting in a substantial volume of by-products, which still have an interesting composition in secondary metabolites, especially glucosinolates. Therefore, a green extraction procedure of glucosinolates by Pressurised Liquid Extraction was developed and optimized using a chemometric approach. Furthermore, the glucosinolates were purified by solid phase extraction, and a preliminary study on bioaccessibility and bioavailability study was carried out to evaluate the resistance of the glucosinolates to the digestive process. The application of pressurised liquid extraction to the recovery of glucosinolates from camelina sativa by-product, is a green, automatic, and rapid method, representing a valid alternative to conventional extraction method to obtain ingredients for food industries.

Optimizing the Extraction of the Polyphenolic Fraction from Defatted Strawberry Seeds for Tiliroside Isolation Using Accelerated Solvent Extraction Combined with a Box-Behnken Design

Tiliroside is a natural polyphenolic compound with a wide range of biological activity, and defatted strawberry seeds are its rich source. The goal of this study was to optimize accelerated solvent extraction (ASE) conditions, including temperature, solvent composition, and the number of extraction cycles, using Box-Behnken design to maximize the yield of tiliroside. UPLC-DAD-MS was applied to investigate the polyphenolic composition of the extracts, and preparative liquid chromatography (pLC) was used for isolation. All obtained mathematical models generally showed an increase in the efficiency of isolating polyphenolic compounds with an increase in temperature, ethanol content, and the number of extraction cycles. The optimal established ASE conditions for tiliroside were as follows: a temperature of 65 °C, 63% ethanol in water, and four extraction cycles. This allowed for the obtainment of a tiliroside-rich fraction, and the recovery of isolated tiliroside from plant material reached 243.2 mg from 100 g. Our study showed that ASE ensures the isolation of a tiliroside-rich fraction with high effectiveness. Furthermore, defatted strawberry seeds proved to be a convenient source of tiliroside because the matrix of accompanying components is relatively poor, which facilitates separation.

Investigation of Health Effects of Major Phenolic Compounds in Foods: Extraction Processes, Analytical Approaches and Applications

The escalating costs of healthcare services and a growing awareness of personal health responsibilities have led individuals to explore natural methods alongside conventional medicines for health improvement and disease prevention. The aging global population is experiencing increased health needs, notably related to conditions like diabetes, heart disease, and hypertension. Lifestyle-related diseases, poor dietary habits, and sedentary lifestyles underscore the importance of foods containing nutrients that can aid in preventing and managing these diseases. Phenolic compounds, a fundamental group of phytochemicals, are prominent in the chemical diversity of the natural world and are abundant in functional foods. Widely distributed in various plant parts, these compounds exhibit important functional and sensory properties, including color, taste, and aroma. Their diverse functionalities, particularly antioxidant activity, play a crucial role in mitigating cellular oxidative stress, potentially reducing damage associated with serious health issues such as cardiovascular disease, neurodegenerative disea23ses, and cancer. Phenolic compounds exist in different forms, some combined with glycosides, impacting their biological effects and absorption. Approximately 8000 polyphenols isolated from plants offer significant potential for natural medicines and nutritional supplements. Therefore, their extraction process and selective and sensitive food determination are very important. This review focuses on the extraction processes, analytical methods, and health effects of major phenolic compounds in foods. The examination encompasses a comprehensive analysis of analytical approaches and their applications in elucidating the presence and impact of these compounds on human health.

Drying Technique Providing Maximum Benefits on Hydrogelling Ability of Avocado Seed Protein: Spray Drying

The current study focused on creating natural hydrogels consisting of mixtures of avocado seed proteins dried with different techniques and locust bean gum. Proteins were extracted from avocado seed by alkali and isoelectric precipitation methods. Avocado seed proteins were dried by five different drying methods, namely ambient drying, oven drying, vacuum drying, freeze drying, and spray drying. FT-IR spectra were used to analyze the chemical structure of proteins dried using various techniques. Additionally, hydrogel models were constructed in the presence of avocado seed proteins and locust bean gum to clarify the effect of drying techniques on their hydrogelling ability. The impact of drying techniques on the functional behavior of hydrogels was notable. The maximum water holding capacity values were detected in the hydrogel system containing spray-dried proteins (93.79%), followed by freeze-dried (86.83%), vacuum-dried (76.17%), oven-dried (72.29%), and ambient-dried (64.8%) counterparts. The swelling ratio was 34.10, 33.51, 23.05, 18.93, and 14.39% for gels in the presence of freeze-dried, spray-dried, vacuum-dried, oven-dried, and ambient-dried proteins, respectively. Additionally, the desirable values for the amount of protein leaking from the systems prepared using spray-dried (7.99%) and freeze-dried (12.14%) proteins were obtained compared to others (ambient-dried: 24.03%; oven-dried: 17.69%; vacuum-dried: 19.10%). Superior results in terms of textural properties were achieved in hydrogel models containing spray-dried and freeze-dried proteins. In general, hydrogel models exhibited elastic behavior rather than viscous properties; however, the magnitudes of elasticity varied. Furthermore, the success of gels containing hydrogel models containing spray-dried protein and locust bean gum in the bioactive compound delivery system was obvious compared with protein ones alone.

Response Surface Methodology for the Optimization of Flavan-3-ols Extraction from Avocado By-Products via Sonotrode Ultrasound-Assisted Extraction

Avocado peel and seed are the main by-products of avocado processing and are considered as promising sources of phenolic compounds with biological activities. Thus, this research focuses on the establishment, for the first time, of ultrasound-assisted extraction of flavan-3-ols with high antioxidant activity from avocado peel and seed using a sonotrode. Indeed, 2 Box-Behnken designs were performed for 15 experiments, with each design having three independent factors (ratio ethanol/water (v/v), time (min) and amplitude (%)). In both models, the responses included total procyanidins (flavan-3-ols) measured via HPLC-FLD and antioxidant activity measured via DPPH, ABTS and FRAP. The results showed that applying the sonotrode extraction method could increase flavan-3-ols recovery by 54% and antioxidant activity by 62-76% compared to ultrasound bath technology. Therefore, this technology was demonstrated to be a non-thermal, low time-consuming and scalable method that allowed the recovery of flavan-3-ols from avocado by-products that could be used as functional ingredients.

Valorization of Avocado Seed Wastes for Antioxidant Phenolics and Carbohydrates Recovery Using Deep Eutectic Solvents (DES)

Avocado seeds represent the chief waste produced in avocado processing, leading not only to environmental problems regarding its elimination but to a loss of economic profitability. In fact, avocado seeds are known as interesting sources of bioactive compounds and carbohydrates, so their utilization may reduce the negative effect produced during the industrial manufacture of avocado-related products. In this sense, deep eutectic solvents (DES) are a novel greener alternative than organic solvents to extract bioactive polyphenols and carbohydrates. The study was based on a Box-Behnken experimental design to study the effect of three factors, temperature (40, 50, 60 °C), time (60, 120, 180 min) and water content (10, 30, 50% v/v) on the responses of total phenolic (TPC) and flavonoid content (TFC), antioxidant capacity (measured as ABTS and FRAP) and xylose content in the extract. The DES Choline chloride:glycerol (1:1) was used as solvent on avocado seed. Under optimal conditions, TPC: 19.71 mg GAE/g, TFC: 33.41 mg RE/g, ABTS: 20.91 mg TE/g, FRAP: 15.59 mg TE/g and xylose: 5.47 g/L were obtained. The tentative identification of eight phenolic compounds was assayed via HPLC-ESI. The carbohydrate content of the solid residue was also evaluated, and that solid was subjected to two different processing (delignification with DES and microwave-assisted autohydrolysis) to increase the glucan susceptibility to enzymes, and was also assayed reaching almost quantitative glucose yields. These results, added to the non-toxic, eco-friendly, and economic nature of DES, demonstrate that these solvents are an efficient alternative to organic solvents to recover phenolics and carbohydrates from food wastes.

Microwave-Assisted Extraction Optimization and Effect of Drying Temperature on Catechins, Procyanidins and Theobromine in Cocoa Beans

Cocoa beans (Theobroma cacao L.) are an important source of polyphenols. Nevertheless, the content of these compounds is influenced by post-harvest processes. In this sense, the concentration of polyphenols can decrease by more than 50% during drying. In this study, the process of procyanidins extraction was optimized and the stability of catechins, procyanidins, and theobromine to different drying temperatures was evaluated. First, the effectiveness of methanol, ethanol, acetone, and water as extract solvents was determined. A Box-Behnken design and response surface methodology were used to optimize the Microwave-Assisted Extraction (MAE) process. The ratios of methanol-water, time, and temperature of extraction were selected as independent variables, whereas the concentration of procyanidins was used as a response variable. Concerning the drying, the samples were dried using five temperatures, and a sample freeze-dried was used as a control. The quantitative analyses were carried out by HPLC-DAD-ESI-IT-MS. The optimal MAE conditions were 67 °C, 56 min, and 73% methanol. Regarding the drying, the maximum contents of procyanidins were obtained at 40 °C. To our knowledge, this is the first time that the stability of dimers, trimers, and tetramers of procyanidins on drying temperature was evaluated. In conclusion, drying at 40 °C presented better results than the freeze-drying method.

Isolation of Garlic Bioactives by Pressurized Liquid and Subcritical Water Extraction

Garlic (Allium sativum L.) is widely used in various food products and traditional medicine. Besides unique taste and flavour, it is well known for its chemical profile and bioactive potential. The aim of this study was to apply subcritical water extraction (SWE) and pressurized liquid extraction (PLE) for the extraction of bioactive compounds from the Ranco genotype of garlic. Moreover, PLE process was optimized using response surface methodology (RSM) in order to determine effects and optimize ethanol concentration (45-75%), number of cycles (1-3), extraction time (1-3 min) and temperature (70-110 °C) for maximized total phenols content (TP) and antioxidant activity evaluated by various in vitro assays. Furthermore, temperature effect in SWE process on all responses was evaluated, while allicin content (AC), as a major organosulphur compound, was determined in all samples. Results indicated that PLE provided tremendous advantage over SWE in terms of improved yield and antioxidant activity of garlic extracts. Therefore, high-pressure processes could be used as clean and green procedures for the isolation of garlic bioactives.

Optimization of accelerated aqueous ethanol extraction to obtain a polyphenol-rich crude extract from rambutan (Nephelium lappaceum L.) peel as natural antioxidant

An accelerated solvent extraction method was used to recover polyphenol-rich crude extract from rambutan (Nephelium lappaceum L.) peel, a waste product from the canning industry. The influence of extraction parameters including temperature, extraction time and ethanol concentration on extraction yield, total phenolic content, total anthocyanin content, and ABTS antioxidant activity was investigated. A Box-Behnken design and response surface methodology were used to optimize the extraction process. Optimal conditions were obtained at temperature, extraction time, and ethanol concentration of 60 °C, 34 min, and 54 vol%, respectively. These optimum conditions gave 333.01 ± 5.84 mg gallic acid/g, 318.28 ± 5.56 mg cyanidin-3-O-glucoside/g, and 3.05 ± 0.04 mmol Trolox/mg for total phenolic content, total anthocyanins content, and ABTS activity, respectively with extraction yield of 28.68 ± 1.48 wt%. Important active compounds found in the extract were geraniin, ellagic acid, shikimic acid and corilagin. Crude extract concentrations of 50-500 mg/kg retarded linoleic acid oxidation but efficacy was lower than synthetic antioxidants at 200 mg/kg. The current findings indicated that accelerated aqueous ethanol extraction was an effective method for the recovery of a crude extract rich in polyphenols from rambutan peel with the potential to be used as a natural antioxidant.

Extraction Systems and Analytical Techniques for Food Phenolic Compounds: A Review

Phenolic compounds are highly valuable food components due to their potential utilisation as natural bioactive and antioxidant molecules for the food, cosmetic, chemical, and pharmaceutical industries. For this purpose, the development and optimisation of efficient extraction methods is crucial to obtain phenolic-rich extracts and, for some applications, free of interfering compounds. It should be accompanied with robust analytical tools that enable the standardisation of phenolic-rich extracts for industrial applications. New methodologies based on both novel extraction and/or analysis are also implemented to characterise and elucidate novel chemical structures and to face safety, pharmacology, and toxicity issues related to phenolic compounds at the molecular level. Moreover, in combination with multivariate analysis, the extraction and analysis of phenolic compounds offer tools for plant chemotyping, food traceability and marker selection in omics studies. Therefore, this study reviews extraction techniques applied to recover phenolic compounds from foods and agri-food by-products, including liquid-liquid extraction, solid-liquid extraction assisted by intensification technologies, solid-phase extraction, and combined methods. It also provides an overview of the characterisation techniques, including UV-Vis, infra-red, nuclear magnetic resonance, mass spectrometry and others used in minor applications such as Raman spectroscopy and ion mobility spectrometry, coupled or not to chromatography. Overall, a wide range of methodologies are now available, which can be applied individually and combined to provide complementary results in the roadmap around the study of phenolic compounds.

Avocado seed discoveries: Chemical composition, biological properties, and industrial food applications

The processing industry discards avocado seeds, which increases production and ultimately pollutes the environment. It would be advantageous to handle these waste by-products both economically and environmentally. Avocado seeds are rich in polysaccharides, proteins, lipids, vitamins, minerals, and other bioactive substances. The nutritional and phytochemical composition of avocado seeds has been well studied and discussed. Avocado-seed extracts also have many health-related bioactive properties, such as anti-hyperglycaemic, anticancer, anti-hypercholesterolemia, antioxidant, anti-inflammatory, and anti-neurogenerative effects are clearly demonstrated how these properties can be used to formulate or fortify food. The health-promoting properties of avocado seeds have been studied. These properties are attributed to various phytochemicals, such as acetogenin, catechin, epicatechin, procyanidin B1, estragole, etc. Additionally, items made from valorized avocado seeds that people can consume have been explored. The best applications of valorized by-products have been created for the pharmaceutical, functional food, and nutraceutical sectors while considering quality and safety. More clinical testing and product development research are required to prove the effectiveness of avocado seeds.

Potential and prospects for utilization of avocado by-products in integrated biorefineries

The industrial processing of avocado to extract oil, and produce guacamole or sauces generates enormous quantities of peels and seeds (around 2 million tons worldwide in 2019) without commercially valuable applications. However, various studies have suggested the presence of a wide range of interesting compounds in the composition of these by-products. This review depicts a thorough outline of the capacity of avocado residues to be converted into a portfolio of commodities that can be employed in sectors such as the food, cosmetics, pharmaceuticals, environment, and energy industries. Therefore, a novel biorefinery strategy to valorize avocado-processing residues to obtain a polyphenolic extract, pectooligosaccharides, and succinic acid was presented. Additionally, the prospects and challenges facing a biorefinery based on the valorization of avocado residues are presented, particularly its techno-economic feasibility on an industrial scale, aiming for a resource-efficient circular bio-economy.

Green Extraction Methods for Recovery of Antioxidant Compounds from Epicarp, Seed, and Seed Tegument of Avocado var. Hass (Persea americana Mill.)

The present study compared the extracts obtained from the epicarp, seed, and seed tegument of avocado var. Hass with pressurized liquid extraction (PLE) and ultrasound-assisted extraction (UAE). The extracts were quantified in terms of total phenolic content (TPC) and antioxidant capacity (AC). The PLE extracts had a global yield ( $X_0$ ) like that obtained with UAE using ethanol (Et) as the solvent. For the TPC, the extracts obtained with both techniques showed no significant differences ( $p>0.05$ ). On the other hand, the epicarp extracts obtained with PLE had higher values for AC: 829.8 μmol TE/gDe (ABTS) and 3,215.1 μmol Fe2+/g De (FRAP), recorded for UAE/Et. The AC in the avocado residue extracted with PLE suggested a high potential for applications in food, pharmaceutical, and cosmetology products.

Edible plant by-products as source of polyphenols: prebiotic effect and analytical methods

Polyphenols with high chemical diversity are present in vegetables both in the edible parts and by-products. A large proportion of them remains unabsorbed along the gastrointestinal tract, being accumulated in the colon, where they are metabolized by the intestinal microbiota. These polyphenols have been found to have "prebiotic-like" effects. The edible plant industry generates tons of residues called by-products, which consist of unutilized plant tissues (peels, husks, calyxes and seeds). Their disposal requires special and costly treatments to avoid environmental complications. Reintroducing these by-products into the value chain using technological and biotechnological practices is highly appealing since many of them contain nutrients and bioactive compounds, such as polyphenols, with many health-promoting properties. Edible plant by-products as a source of polyphenols highlights the need for analytical methods. Analytical methods are becoming increasingly selective, sensitive and precise, but the great breakthrough lies in the pretreatment of the sample and in particular in the extraction methods. This review shows the importance of edible plant by-products as a source of polyphenols, due to their prebiotic effect, and to compile the most appropriate analytical methods for the determination of the total content of phenolic compounds as well as the detection and quantification of individual polyphenols.

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.

Hydrothermal treatment of avocado peel waste for the simultaneous recovery of oligosaccharides and antioxidant phenolics

Avocado industrial processing generates huge quantities of residues that are currently wasted without any valuable commercial application. This work deals with autohydrolysis of Avocado peel (AP) for the concomitant recovery of oligosaccharides and polyphenolics. Temperature of 150 °C allowed the highest recovery of oligosaccharides (14.3 g oligosaccharides/100 g AP) and high recovery of antioxidant phenolics (3.48 g gallic acid equivalents/100 g AP and 10.80 g Trolox equivalents/100 g AP measured with ABTS^●+ assay). The liquor obtained at this temperature was characterized by TGA and FTIR to study its thermal stability and functional groups. UHPLC-TOF MS analysis of an ethyl acetate extract of AP liquor enabled the tentative identification of 43 compounds, belonging to various metabolite families, including flavonoids, phenolic acids, organic acids, lignans and fatty acids. These findings demonstrated that autohydrolysis of AP is a suitable technology to obtain bioactive agents with potential uses in food and cosmetic industries.

Exploiting the Potential of Bioactive Molecules Extracted by Ultrasounds from Avocado Peels-Food and Nutraceutical Applications

Natural bioactive compounds from food waste have fomented interest in food and pharmaceutical industries for the past decade. In this work, it purposed the recovery of bioactive avocado peel extract using an environmentally friendly technique: the ultrasound assisted extraction. The response surface methodology was applied in order to optimize the conditions of the extraction, ethanol-water mixtures and time. The optimized extracts (ethanol 38.46%, 44.06 min, and 50 °C) were chemically characterized by HPLC-ESI-MS and FTIR. Its antioxidant ability, as well as, its effect on cell metabolic activity of normal (L929) and cancer (Caco-2, A549 and HeLa) cell lines were assessed. Aqueous ethanol extracts presented a high content in bioactive compounds with high antioxidant potential. The most representative class of the phenolic compounds found in the avocado peel extract were phenolic acids, such as hydroxybenzoic and hydroxycinnamic acids. Another important chemical group detected were the flavonoids, such as flavanols, flavanonols, flavones, flavanones and chalcone, phenylethanoids and lignans. In terms of its influence on the metabolic activity of normal and cancer cell lines, the extract does not significantly affect normal cells. On the other hand, it can negatively affect cancer cells, particularly HeLa cells. These results clearly demonstrated that ultrasound is a sustainable extraction technique, resulting in extracts with low toxicity in normal cells and with potential application in food, pharmaceutical or nutraceutical sectors.

Recent advances in extraction technologies for recovery of bioactive compounds derived from fruit and vegetable waste peels: A review

Fruits and vegetables are the most important commodities of trade value among horticultural produce. They are utilized as raw or processed, owing to the presence of health-promoting components. Significant quantities of waste are produced during fruits and vegetables processing that are majorly accounted by waste peels (∼90-92%). These wastes, however, are usually exceptionally abundant in bioactive molecules. Retrieving these valuable compounds is a core objective for the valorization of waste peel, besides making them a prevailing source of beneficial additives in food and pharmaceutical industry. The current review is focused on extraction of bioactive compounds derived from fruit and vegetable waste peels and highlights the supreme attractive conventional and non-conventional extraction techniques, such as microwave-assisted, ultrasound assisted, pulsed electric fields, pulsed ohmic heating, pressurized liquid extraction, supercritical fluid extraction, pressurized hot water, high hydrostatic pressure, dielectric barrier discharge plasma extraction, enzyme-assisted extraction and the application of "green" solvents say as well as their synergistic effects that have been applied to recover bioactive from waste peels. Superior yields achieved with non-conventional technologies were identified to be of chief interest, considering direct positive economic consequences. This review also emphasizes leveraging efficient, modern extraction technologies for valorizing abundantly available low-cost waste peel, to achieve economical substitutes, whilst safeguarding the environment and building a circular economy. It is supposed that the findings discussed though this review might be a valuable tool for fruit and vegetable processing industry to imply an economical and effectual sustainable extraction methods, converting waste peel by-product to a high added value functional product.

Persea Americana Agro-Industrial Waste Biorefinery for Sustainable High-Value-Added Products

Significant problems have arisen in recent years, such as global warming and hunger. These complications are related to the depletion and exploitation of natural resources, as well as environmental pollution. In this context, bioprocesses and biorefinery can be used to manage agro-industrial wastes for obtaining high-value-added products. A large number of by-products are composed of lignin and cellulose, having the potential to be exploited sustainably for chemical and biological conversion. The biorefinery of agro-industrial wastes has applications in many fields, such as pharmaceuticals, medicine, material engineering, and environmental remediation. A comprehensive approach has been developed toward the agro-industrial management of avocado (Persea americana) biomass waste, which can be transformed into high-value-added products to mitigate global warming, save non-renewable energy, and contribute to health and science. Therefore, this work presents a comprehensive review on avocado fruit waste biorefinery and its possible applications as biofuel, as drugs, as bioplastics, in the environmental field, and in emerging nanotechnological opportunities for economic and scientific growth.

Artichoke By-Products as Natural Source of Phenolic Food Ingredient

Nowadays, the transformation activity of the food industry results in the generation of a huge amount of daily discarded vegetables wastes. One of those undervalued by-products are produced during the post-harvesting and processing process of artichokes. In the present research, the potential of artichokes’ bracts and stalks have been evaluated as a natural source of phenolic compounds which could be used as bioactive food ingredients, among others. In this study, the bioactive composition of those wastes has been evaluated using recent advances in extraction and analytical technologies, concretely, pressurized liquid extraction (PLE) followed by high-performance liquid chromatography (HPLC) coupled to electrospray time-of flight mass spectrometry (ESI-TOF/MS) analysis. To achieve this goal, first, the extraction process was evaluated by a comparative study using GRAS (Generally Recognized As Safe) solvents (mixtures of ethanol and water) at different temperatures (40–200 °C). The second step was to deeply characterize the composition of individual polyphenols by HPLC-ESI-TOF/MS in order to establish a comparison among the different PLE conditions applied to extract the phenolic fraction. The analysis revealed a wide variety of phenolic-composition, mainly phenolic acids and flavonoids. The results also highlighted that high percentages of ethanol and medium-high temperatures pointed out to be useful PLE conditions for recovering this kind of phytochemicals, which could be used in different applications, such as functional food ingredients, cosmetics, or nutraceuticals.

Influence of Drying Methods on Bioactive Properties,Fatty Acids and Phenolic Compounds of Different Parts of Ripe and Unripe Avocado Fruits

All drying processes increased oil content, antioxidant activity, total phenolic contents, and most of the phenolic compounds in the pulp, peel and seeds of both ripe fruits with varied degrees (p < 0.05). In addition, the processes reduced the oil contents, linoleic acids, 3,4-dihydroxybenzoic acid, (+)-catechin, and naringenin of the pulp, antioxidant activity of the peels and seeds, and 3,4-dihydroxybenzoic acid, (+)-catechin of the seeds and it enhanced all other parameters in the pulp, peel, and seeds of unripe fruits (p < 0.05). Comparing the phenolic profiles of avocado pulp, peels, and seeds of ripe and unripe fruits indicated that the peel and seeds are richer than the pulp and that is superior in unripe fruits than ripe ones. In addition, drying processes particularly microwave and air drying greatly enhanced the bioactive properties of ripe and unripe avocado fruits and could thus be used to elongate the shelf-life of avocado fruit products without major impact on the overall quality.

The Effects of Avocado Waste and Its Functional Compounds in Animal Models on Dyslipidemia Parameters

Ischemic heart disease and stroke are two main causes of death that have prevailed for more than 15 years. Dyslipidemia and its parameters like hypercholesterolemia, hypertriglyceridemia, increase in low-density cholesterol, and a reduction of high-density cholesterol have been related with heart disease and risk of stroke. Approaches to improve the health and specifically reduce the risk of heart disease, such as medications and dietary interventions have been effective, but there are other potential sources of biological compounds that could have an effect due to their antioxidant properties. Avocado is a commonly consumed fruit especially its pulp, while the peel, seed, and leaf are usually discarded as waste. Some researchers have reported antioxidant, hepatoprotective, gastroprotective, lipid-lowering, and hypoglycemic effects in these wastes. In this review article, we have summarized the current evidence on the effect of biological compounds from avocado waste on dyslipidemia parameters in preclinical models. Also, we have included the compound extracted and the extraction method from the selected articles.

Functional ingredient from avocado peel: Microwave-assisted extraction, characterization and potential applications for the food industry

Avocado peel is a by-product obtained in high amounts in the food industry with no further applications despite its richness in bioactive compounds. In this context, an efficient "green" microwave assisted extraction (MAE) was optimized to maximize the extraction of bioactive polyphenols. Moreover, the phenolic composition of the developed green avocado extract was characterized by HPLC coupled to MS analysers and the potential applications for the food industry were studied assaying different bioactivities. Thus, the matrix metalloproteinases inhibition, the antioxidant capacity and the antimicrobial activity against gram-positive and gram-negative bacteria, yeast and mold were tested. The results pointed out both, high matrix metalloproteinases inhibitory capacity and antioxidant activity of avocado peel MAE extract. These findings suggest the potential food industry applications of this extract as natural food preservative, functional food ingredient or nutraceuticals with antioxidant and anti-aging activities.

Development of an Innovative Pressurized Liquid Extraction Procedure by Response Surface Methodology to Recover Bioactive Compounds from Carao Tree Seeds

Nowadays there are evidences from several studies which have revealed the protective effects of food against chronic diseases. These healthy properties have been related to bioactive compounds. Among bioactive substances, the scientific interest in phenolic compounds has stimulated multidisciplinary research on the composition of plant phenolic compounds. The aim of this work has been to determine the bioactive composition of Carao tree seeds (Cassia grandis) and to optimize the recovering of these compounds for developing functional ingredients. To achieve this goal, pressurized liquid extraction (PLE) has been applied to recover these phytochemicals. The optimization of this innovative extraction procedure was performed by a response surface methodology (RSM) based on a central composite design 2³ model to address the bioactive compounds extraction. Phenolic compounds recovered by PLE were characterized using reversed-phase high-performance liquid chromatography coupled to electrospray ionization time-of-flight mass spectrometry (HPLC-ESI-TOF-MS). Analytical characterization allowed the identification and quantitation of phenolic compounds belonging to hydroxybenzoic acids and flavonoids (flavonols, flavanols, flavanones and proanthocyanidins). Phytochemical concentrations were used as response variable in order to get the best extraction conditions. These results pointed out that Carao tree seeds can be a potential source of bioactive compounds and PLE extracts could be used as functional ingredients.

Fractionation and Hydrolyzation of Avocado Peel Extract: Improvement of Antibacterial Activity

Avocado Hass (Persea americana Mill) peel extract (APE) has the potential as a natural ingredient to substitute for chemical preservatives. The objectives of this study were to assess the phytochemical composition by high-performance liquid chromatography-quadrupole time-of-flight mass/mass spectrometry (HPLC-qTOF-MS/MS), total phenolic content (TPC), proanthocyanidin (PAC) content, and antioxidant activity of the APE, the organic fraction (OF), the aqueous fraction (AF), and the acid-microwave hydrolyzed APE (HAPE), on the antibacterial activity (ABA). The results indicated that APE and OF contained (p ˂ 0.05) a higher phenolic composition and antioxidant activity than AF and HAPE. The ABA specified that Pseudomonas aeruginosa and Bacillus cereus were inhibited by all the extracts (minimal inhibitory concentration-MIC ≥ 500 µg/mL), Staphylococcus aureus was only significantly inhibited by APE (≥750 µg/mL), the same MIC was observed for the OF on Salmonella spp. and Listeria monocytogenes. The HAPE increased the inhibitory efficiency up to 25% on Escherichia coli and Salmonella spp. (MIC ≥ 750 µg/mL), and 83.34% on L. monocytogenes (MIC ≥ 125 µg/mL) compared to APE (MIC ≥ 750 µg/mL). Also, HAPE inhibited the biofilm formation at the lowest concentration (125 µg/mL); meanwhile, the biofilm disruption showed to be concentration-time-dependent (p ˃ 0.05) compared to amoxicillin. In conclusion, the fractionation and hydrolyzation of APE improved the ABA; thus, those strategies are useful to design new antimicrobial compounds.

Avocado fruit and by-products as potential sources of bioactive compounds

The increased demand for avocado, and therefore production and consumption, generate large quantities of by-products such as seeds, peel, and defatted pulp, which account for approximately 30% of fruit weight, and which are commonly discarded and wasted. The present review focuses on various compounds present in avocado fruit and its by-products, with particular interest to those that can be potentially used in different industrial forms, such as nutraceuticals, to add to or to formulate functional foods, among other uses. Main molecular families of bioactive compounds present in avocado include phenolic compounds (such as hydroxycinnamic acids, hydroxybenzoic acids, flavonoids and proanthocyanins), acetogenins, phytosterols, carotenoids and alkaloids. Types, contents, and possible functions of these bioactive compounds are described from a chemical, biological, and functional approach. The use of avocado and its by-products requires using processing methods that allow highest yield with the least amount of unusable residues, while also preserving the integrity of bioactive compounds of interest. Avocado cultivar, fruit development, ripening stage, and processing methods are some of the main factors that influence the type and amount of extractable molecules. The phytochemical diversity of avocado fruit and its by-products make them potential sources of nutraceutical compounds, from which functional foods can be obtained, as well as other applications in food, health, pigment, and material sectors, among others.

Determination of Phenolic Compounds, Procyanidins, and Antioxidant Activity in Processed Coffea arabica L. Leaves

The effects of dry processing and maturity on antioxidant activity, total phenolic content, total procyanidins, and identity of phenolic compounds in coffee leaves were evaluated. Fresh coffee leaves were tray-dried at 40 °C for 8 h before total phenolic content, total procyanidins, and antioxidant activity were analyzed. The drying process significantly (p < 0.05) improved the release of total phenolic content and total procyanidins compared with the fresh leaves. The results showed that the young leaves exposed to drying processes had the highest total phenolic content, total procyanidins, and DPPH radical scavenging activity. Therefore, the effect of different drying temperatures (30, 40, and 50 °C) in the young leaves were further analyzed. The results indicated that DPPH radical scavenging activity, total phenolic content, and total procyanidins were increasingly generated when exposed to an increase in drying temperatures, whereby the highest bioactivity was evident at 50 °C. The DPPH radical scavenging activity of the coffee leaf teas was significantly correlated with total phenolic content and total procyanidins. Identification of Coffea arabica L. bioactive compounds by LC-MS showed the presence of catechin or epicatechin, mangiferin or isomangiferin, procyanidin B, caffeoylquinic acids (CQA), caffeine, quercetin-3-O-glucoside, procyanidin C, rutin, and 3,4-diCQA. Coffea arabica L. leaf tea was confirmed to be a potential functional food rich in phenolic compounds with strong antioxidant activity.

Byproduct Generated During the Elaboration Process of Isotonic Beverage as a Natural Source of Bioactive Compounds

Agro-industrial byproducts are considered good sources of macronutrients and phytochemicals. Fruit and vegetable residues (FVR), obtained after the production of an isotonic beverage, have previously been characterized containing 80% insoluble dietary fibers from total fibers (48.4%), 26% available carbohydrates, 9.5% proteins and 5% lipids. Nevertheless, fruit and vegetables provide phytochemicals which have been related to human health such as phenolic compounds. The loss of specific compounds over the production process is related to their partitioning between fruit and vegetables and byproducts. However, phenolic profile of FVR remains unknown. This work is focused on the evaluation of FVR as a natural source of these bioactive compounds. For this purpose, pressurized liquid extraction (PLE) has been proposed as extraction technique for recovering phenolic compounds from FVR. The experimental variables were temperature and percentage of solvent (ethanol and water). Phenolic compounds extracts were characterized by UPLC-ESI-Q-TOF-MS and a discussion about phenolic and macronutrient interactions was established. Globally, 88 compounds were tentatively identified: phenolic acids (28), flavonoids (32), and other polyphenols (28). The PLE conditions applied yielded different breaking matrix-analyte interactions leading to an increase in the number of compounds. The highest phenolic acids content was achieved with high temperature while lower temperatures were more efficient in extracting flavonoid. By establishing the phenolics profile in food byproducts such as FVR, it is possible to more effectively apply these byproducts as nutraceutical, food or pharmaceutical ingredients.

PRACTICAL APPLICATION

Flow diagram of bioactive compounds recovering from isotonic beverage byproduct is proposed using pressurized liquid extraction. The plant-bioactives mechanism relies on fruit and vegetable byproducts changes under different extraction conditions. The obtained extracts can most effectively be applied as nutraceuticals or as ingredients in food or pharmaceutical inputs.

Rapid determination of Alternaria mycotoxins in tomato samples by pressurised liquid extraction coupled to liquid chromatography with fluorescence detection

A sensitive and reliable method using pressurised liquid extraction (PLE) followed by molecularly imprinted solid phase extraction (MISPE) and high performance liquid chromatography with fluorescence detection (HPLC-FLD) has been developed for the analysis of alternariol (AOH) and alternariol monomethyl ether (AME) in tomato samples. Influence of several extraction parameters that affect PLE efficiency were evaluated for the simultaneous extraction of both mycotoxins in the selected samples. AOH and AME were optimally extracted using MeOH/water (25:75, v/v) at 70°C as solvent, a pressure of 1000 psi and a single extraction cycle. The resulting PLE extracts were pre-concentrated by molecularly imprinted solid phase extraction (MISPE) cartridges followed of analysis by HPLC with fluorescence detection (λ_exc = 258, λ_em = 440 nm). The proposed method was applied to the analysis of AOH and AME in fortified tomato samples (20-72 µg· kg-1) with recoveries of 84-97% (RSD < 8%, n = 6) for AOH and 67-91% (RSD < 13%, n = 6) for AME. The detection limit for AOH and AME were 7 and 15 µg· kg^-1, respectively. The ensuing PLE-MISPE-HPLC-FLD method was validated for the analysis of both mycotoxins in tomato samples in accordance with European Commission Decision 2002/657/EC.