Potential of fruit wastes as natural resources of bioactive compounds

The Use of Antioxidants in the Treatment of Migraine

Despite numerous studies concerning the pathophysiology of migraine, the exact molecular mechanism of disturbances underlying migraine is still unknown. Furthermore, oxidative stress is considered to play a significant role in migraine pathogenesis. The notion of oxidative stress in migraine patients has been discussed for several decades. Over the past few years, among the substances that could potentially be used for migraine treatment, particular attention has been paid to the so-called nutraceutics, including antioxidants. Antioxidants supplied with food prevent oxidative stress by inhibiting initiation, propagation, and the oxidative chain reaction itself. Additionally, the agents used so far in the prevention of migraine indeed show some anti-oxidative action. The antioxidants discussed in the present paper are increasingly more often used by migraine patients not only due to mild or even a lack of side effects but also because of their effectiveness (decreased frequency of migraine episodes or shortening of an episode duration). The present review provides a summary of the studies on nutraceuticals with antioxidative properties.

Antibacterial Activity Test of Ethanol Extract Pineapple (Ananas comosus (L.) Merr.) Peel against Growth of Propionibacterium acnes

Pineapple peel (Ananas comosus (L.) Merr.) is waste from the pineapple fruit. The purpose of this study was to determine the content of pineapple peel extract and to antibacterial activity in various concentrations effective in inhibiting the growth of Propionibacterium acnes. The pineapple peel extract is made by using the extraction method in the form of maceration. The method used in the inhibitory test using the three replication samples in each treatment group. The sample consisted of 10 treatment groups ie pineapple peel extract concentration 12.5%, 25%, 37.5%, 50%, 62.5%, 75%, 87.5%, and 100%, as well as positive and negative control. The results obtained from pineapple peel screening contain flavonoid and saponin compounds. The data analysis shows that pineapple peel extract concentrations of 50%, 62.5%, 75%, 87.5%, and 100% had inhibitory zones with the medium-strong category while clindamycin as the control has a strong inhibition zone. The conclusion of this research proves that pineapple peel extract has antibacterial power to P. acnes with effective concentration is 100% with the strong category.

Fruit Seeds as Sources of Bioactive Compounds: Sustainable Production of High Value-Added Ingredients from By-Products within Circular Economy

The circular economy is an umbrella concept that applies different mechanisms aiming to minimize waste generation, thus decoupling economic growth from natural resources. Each year, an estimated one-third of all food produced is wasted; this is equivalent to 1.3 billion tons of food, which is worth around US$1 trillion or even $2.6 trillion when social and economic costs are included. In the fruit and vegetable sector, 45% of the total produced amount is lost in the production (post-harvest, processing, and distribution) and consumption chains. Therefore, it is necessary to find new technological and environmentally friendly solutions to utilize fruit wastes as new raw materials to develop and scale up the production of high value-added products and ingredients. Considering that the production and consumption of fruits has increased in the last years and following the need to find the sustainable use of different fruit side streams, this work aimed to describe the chemical composition and bioactivity of different fruit seeds consumed worldwide. A comprehensive focus is given on the extraction techniques of water-soluble and lipophilic compounds and in vitro/in vivo functionalities, and the link between chemical composition and observed activity is holistically explained.

Modern Extraction and Purification Techniques for Obtaining High Purity Food-Grade Bioactive Compounds and Value-Added Co-Products from Citrus Wastes

Citrus contains a range of highly beneficial bioactive compounds, such as polyphenols, carotenoids, and vitamins that show antimicrobial and antioxidant properties and help in building the body's immune system. On consumption or processing, approximately 50% of the fruit remains as inedible waste, which includes peels, seeds, pulp, and segment residues. This waste still consists of substantial quantities of bioactive compounds that cause environmental pollution and are harmful to the ecosystem because of their high biological oxygen demand. In recent years, citrus cultivation and the production of processed foods have become a major agricultural industry. In addition to being a substantial source of economy, it is an ideal and sustainable and renewable resource for obtaining bioactive compounds and co-products for food and pharmaceutical industries. In the present article, the various methods of extraction, conventional and modern, as well as separation and isolation of individual bioactive compounds from the extraction mixture and their determination have been reviewed. This article presents both aspects of extraction methods, i.e., on a small laboratory scale and on an industrial mass scale. These methods and techniques have been extensively and critically reviewed with anticipated future perspectives towards the maximum utilization of the citrus waste.

Hypoglycemic, Antiglycation, and Cytoprotective Properties of a Phenol-Rich Extract From Waste Peel of Punica granatum L. var. Dente di Cavallo DC2

Pomegranate peel is a natural source of phenolics, claimed to possess healing properties, among which are antioxidant and antidiabetic. In the present study, an ethyl acetate extract, obtained by Soxhlet from the peel of Dente di Cavallo DC2 pomegranate (PGE) and characterized to contain 4% w/w of ellagic acid, has been evaluated for its hypoglycemic, antiglycation, and antioxidative cytoprotective properties, in order to provide possible evidence for future nutraceutical applications. The α-amylase and α-glucosidase enzyme inhibition, interference with advanced glycation end-products (AGE) formation, and metal chelating abilities were studied. Moreover, the possible antioxidant cytoprotective properties of PGE under hyperglycemic conditions were assayed. Phenolic profile of the extract was characterized by integrated chromatographic and spectrophotometric methods. PGE resulted able to strongly inhibit the tested enzymes, especially α-glucosidase, and exerted chelating and antiglycation properties. Also, it counteracted the intracellular oxidative stress under hyperglycemic conditions, by reducing the levels of reactive oxygen species and total glutathione. Among the identified phenolics, rutin was the most abundant flavonoid (about 4 % w/w). Present results suggest PGE to be a possible remedy for hyperglycemia management and encourage further studies to exploit its promising properties.

Investigation of the chemical composition and biological activity of edible grapevine (Vitis vinifera L.) leaf varieties

Chemical composition and bioactivity of eight edible Vitis vinifera L. leaf varieties originating from Fruška Gora, Serbia, including two autochthonous varieties, were evaluated. The LC-MS/MS analysis confirmed the presence of 28 natural products in leaf samples, among which most abundant were glycosylated flavonoids, ellagic and chlorogenic acids. The highest amounts of most of the tested compounds were detected in leaves of autochthonous variety Sila. Bioactivity was assessed by a set of in vitro antioxidant, neuroprotective and cytotoxic assays. Leaves of all examined varieties exhibited average bioactivity, with leaves of autochthonous variety Župljanka standing out as the most promising sample. To conclude, investigated grapevine leaves proved to be a rich source of nutraceuticals, primarily antioxidants, and their further employment as medicinal food in human diet and beneficial raw material for food, pharmaceutical and cosmetic industries should be supported.

Enhancement of phytoextraction of Pb by compounded activation agent derived from fruit residue

Chelate-assisted phytoextraction is an attractive strategy to remove toxic metals from soil. However, there is lack of an effective and sustainable chelating agent. In this study, 11 kinds of fruit residue were extracted and selected to combine with N, N-bis (carboxymethyl) glutamic acid (GLDA) (0.7%) and tea saponin (4%) for the compounded activation agent (CAA), and its enhancement on Pb phytoextraction by Sedum alfredii was further evaluated by pot experiment. Among 11 fruit residue extracts, lemon residue showed the highest ability (34.7%) to extract Pb from soil. Through combining with GLDA (0.7%) and tea saponin (4%) at the optimal volume ratio of 15:2.5:2.5, the CAA removed Pb most effectively (57.1%) from soil and increased the solubility of three Pb mineral (PbS, PbCO₃ and PbSO₄) by 8.7-56.4 times. In pot experiment, the addition of high dosage (15 mL) CAA increased the biomass of S. alfredii by 52% and doubled the Pb accumulation. In addition, CAA-assisted phytoextraction also increased both water-soluble and acid-soluble Pb in soil, while reduced the proportion of the immobile Pb (oxidizable and residual). Generally, the compounded activation agent derived from lemon residue could be considered as-a promising enhancer for Pb phytoextraction.

Maprang "Bouea macrophylla Griffith" seeds: proximate composition, HPLC fingerprint, and antioxidation, anticancer and antimicrobial properties of ethanolic seed extracts

In this study, the Maprang (Bouea macrophylla Griffith) seeds of 3 Thai varieties of this plant were studied in terms of nutrition, phytochemicals, chemical antioxidants and the bioactivity of their extracts. Maprang seeds revealed high levels of carbohydrates, dietary fiber, energy, potassium, phosphorus, magnesium, and calcium. The Maprang seed extracts possessed a high polyphenolic content and exhibited antioxidant properties against DPPH˙, ABTS˙⁺, and ferric reduction. Additionally, 18-compounds were charaterized by RP-HPLC-DAD with two being recognized as gallic acid and ellagic acid and 16-unknown gallotannins. The HPLC fingerprint was composed of 4 major compounds. The extract showed active growth inhibition against leukemia, lung cancer cell lines and for 15 strains of bacteria. It is known to be particularly effective in drug resistant cells. Our results indicated that maprang seeds are a new natural source of nutrition, minerals and phytochemicals that may be applicable for use as a food supplement and as an effective drug in the treatment of certain diseases.

Phytochemical Composition and Antioxidant Capacity of 30 Chinese Teas

Tea has been reported to prevent and manage many chronic diseases, such as cancer, diabetes, obesity, and cardiovascular diseases, and the antioxidant capacity of tea may be responsible for these health benefits. In this study, the antioxidant capacities of fat-soluble, water-soluble, and bound-insoluble fractions of 30 Chinese teas belonging to six categories, namely green, black, oolong, dark, white, and yellow teas, were systematically evaluated, applying ferric-reducing antioxidant power and Trolox equivalent antioxidant capacity assays. In addition, total phenolic contents of teas were determined by Folin-Ciocalteu method, and the contents of 18 main phytochemical compounds in teas were measured by high-performance liquid chromatography (HPLC). The results found that several teas possessed very strong antioxidant capacity, and caffeine, theaflavine, gallic acid, chlorogenic acid, ellagic acid, and kaempferol-3-O-glucoside, as well as eight catechins, were the main antioxidant compounds in them. Thus, these teas could be good natural sources of dietary antioxidants, and their extracts might be developed as food additives, nutraceuticals, cosmetics, and pharmaceuticals.

Box-Behnken design based multi-objective optimisation of sequential extraction of pectin and anthocyanins from mango peels

Multi-objective sequential fractionation of mango (Mangifera indica L.) peels for pectin and anthocyanins in a biorefinery, was investigated with the aims of enhancing pectin purity, bioactivity and increasing recovered products. Anthocyanins were extracted from mango peels based on a Box-Behnken experimental design (ethanol concentration (50-80%), acetic acid concentration (0.1-2%), time (60-150 min) and temperature (25 °C)). The remaining residue was subsequently fractionated to recover pectin. The optimum anthocyanin conditions (67.45% ethanol, 0.24% acetic acid and 60 min) resulted in pectin with a 5.5% higher antioxidant activity, it was 23% richer in polygalacturonic acid (PGA) and had a yield of 31% w/w higher than conventionally extracted pectin. An anthocyanin extract with anthocyanin contents, polyphenol contents, and antioxidant activity of 22.33 mg/100 g, 132.62 mg/g, and 1.36 μg gallic acid equivalent, respectively, was obtained. Therefore, the sequential extraction of anthocyanins and pectin improves pectin functional properties and increases the mango peel value potential.

Oxidative stability and Sensoric acceptability of functional fish meat product supplemented with plant-based polyphenolic optimal extracts

Background

Fish meat and its products are usually accepted as good source of biological high value food components and especially for polyunsaturated fatty acids. The quality of fish meat products is considered to be decreased by the lipid peroxidation which leads to reduction in nutritional quality, financial loss and severe health problems. Many tactics are present to reserve their quality and safety. In the present investigation, the extraction and supplementation of optimal total polyphenol extracts (TPC) from vegetable and fruit by₋products was explored for lipids oxidative stability and sensoric acceptability of functional fish product samples.

Methods

Vegetable and fruit by₋products (cabbage leaves and banana peels) were collected from local fruits and vegetables processing industries. A 3₋level five factor Box₋Behnken design was used to study the effect of extraction/sonication temperature (°C), amplitude level, water/meal ratio, extraction/sonication time (minutes) and pH conditions for maximum yield of TPC from dried vegetable and fruit samples. The TPC samples were analyzed for chemical composition (total polyphenols, cyanogenic contents and tannins). Natural TPC extracts were supplemented at different concentration (0.5, 1 and 1.5%) to fish meat for preparation of different meat ball samples. The fish meat product samples without supplementation of TPC extract were kept as control. The partial/parfrying of the products was carried out to determine the lipid stability (peroxide value and free fatty acids) stored at refrigerator (for 9 days) and at − 18 °C in a freezer for a storage period of 60₋days. The sensoric analysis (color, flavor and overall acceptability) was performed at different storage intervals for experimental treatments.

Results

The percent values of TPC yield from cabbage leave and banana peel samples ranged from a from minimum value of 9.8 ± 0.12% to a maximum value of 19.8 ± 0.15% for cabbage leaves and minimum value of 15.55 ± 0.13% to a maximum value of 24.4 ± 0.17% for banana peels, respectively. The results revealed that extraction conditions significantly affect the TPC yield from cabbage leaves and banana peels. The cabbage leaves and banana peels contain up to 4.8% total phenolics, cyanogenic compounds (1.44 − 1.47 ± 0.14) and tannins (6.55–7.90 ± 0.22). Peroxide values (meqO₂ /kg) of meat balls treated with TPC extracts at 4 °C were in the range of 1.31 ± 0.12 to 3.10 ± 0.20 while at − 18 °C ranged was found 1.31 ± 0.12 to 1.55 ± 0.17, respectively. Peroxide values of all the treatments increased at the end of second interval then decreased at the end of last storage interval. Peroxide values of all treatments were higher and significantly different at the beginning and the end of the storage period (p <  0.05). In a similar way, free fatty acids and moisture content values trend was recorded for all experimental treatments. Sensory scores of fish product samples for color, flavor and overall acceptability showed a significant difference in sensory scores at refrigeration temperatures where sensory scores of fish product samples decreased significantly (p <  0.05) throughout refrigeration storage. Whereas, the sensory scores at the − 18 °C shows the good sensory characteristics, relatively.

Conclusions

Phenolic extracts containing antioxidant status can interact with free lipidperoxy or lipidoxy free radicals (formed in result of lipid oxidation) and hence stopping their further self₋breakdown. Plant₋based phenolic extracts can be used to decrease oxidation process and increase the shelf life of fish meat products. Additional studies should be undertaken to determine the maximal shelf life of food products supplemented with different plant₋based polyphenol extracts and treatment of nutritional disorders through their absorption, metabolism and distribution pattern into biological tissues.

Phoenix dactylifera L. seeds: a by-product as a source of bioactive compounds with antioxidant and enzyme inhibitory properties

Date (Phoenix dactylifera L.) seeds are a valuable and abundant by-product with various potential food applications and a source of functional and bioactive ingredients.

Potential of Grape Wastes as a Natural Source of Bioactive Compounds

Grapes are widely used in the wine and juice industries, which can lead to massive amounts of waste, mostly grape peels and seeds. The antioxidant capacities, total phenolic and flavonoid contents and phenolic profiles of peels and seeds from 30 grape varieties were systemically assessed. The antioxidant activities of fat-soluble, water-soluble and insoluble-bound fractions of grape peels and seeds were evaluated using ferric-reducing antioxidant power and Trolox equivalent antioxidant capacity assays, and their total phenolic contents and total flavonoid contents were determined by the Folin-Ciocalteu method and AlCl₃ colorimetry, respectively. It was found that the antioxidant capacities were diverse among different grape peels and seeds. Moreover, several phenolic compounds were identified and quantified, including gallic acid, cyanidin-3-glucoside, epicatechin, catechin gallate, ferulaic acid, rutin and resveratrol, which could contribute to the antioxidant capacities of these grape peels and seeds. Several grape wastes with strong antioxidant activity could be abundant sources of natural bioactive compounds, and have the potential for development into functional foods, food additives and pharmaceuticals.

Fiber-Rich Food Processing Byproducts Enhance the Expansion of Cornstarch Extrudates

Expansion characteristics of cornstarch-based extrudates incorporating fiber-rich food processing byproducts was explored. Waxy and regular cornstarch were used as the base materials with apple pomace and sugarcane bagasse incorporated at two addition levels (0%, 15%, and 30% w/w). Extrusions were conducted at three different screw speeds (150, 200, and 250 rpm) with other parameters optimized and kept constant. Apple pomace inclusion resulted in higher initial expansion index (4.23 to 5.60) and higher stable expansion index (2.76 to 4.43), but also showed higher shrinkage (8.50% to 34.72%) than sugarcane bagasse extrudates at the same inclusion levels. Inclusion of apple pomace showed potential of producing extrudates with significantly higher expansion than cornstarch control, with relatively lower energy inputs. Extrusion methods used here have the potential to preserve the textural quality and nutritional value of the fiber-enriched extrudates, providing the base for healthier snack food items.

PRACTICAL APPLICATION

Findings from this study can be extended to the other fiber-rich food processing byproducts, such as other fruit and vegetable pomace, cereal brans, and pulse hulls among other materials. This data will help the development of fiber-enriched extruded snacks that would have favorable consumer traits.

Content of phenolic compounds and vitamin C and antioxidant activity in wasted parts of Sudanese citrus fruits

Phenolic compounds, vitamin C, and the antioxidant activity of wasted parts of citrus (orange, lemon, and grapefruit) fruits were investigated. Ethanolic extracts from whole fruit, peel, and pulp containing seeds of each type of citruses were prepared. Within each type of citrus, results revealed that peels contained a higher amount of phenolic compound, flavonoids, vitamin C, and antioxidant activity than those of their inner wasted parts (pulp and seeds). Peels of grapefruit had the highest total phenolic content followed by lemon and orange, which was found to be 77.3, 49.8, and 35.6 mg of gallic acid equivalent/g of peels, respectively. In contrast, orange peels contain the highest amount of flavonoids (83.3 mg of catechin equivalent/g) and vitamin C (110.4 mg/100 g) compared to the peels of the other citrus fruit used in this study. In general, the high content of antioxidant capacity and activity of citrus waste, particularly the peels, indicated that they may impart health and nutritional benefit when involving in the food industry as a natural antioxidant.

Composition and Physicochemical Characterization of Fiber-Rich Food Processing Byproducts

A wide range of fiber-rich food processing byproducts from various sources have been proposed as value-added ingredients for producing healthier food products. Characterizing their composition and physicochemical properties is crucial to understand their potential uses. Eight fiber-rich byproducts from different sources were fractionated into 2 different particle-size ranges. Different (P ≤ 0.05) proximate composition and physicochemical properties (pasting properties, water-binding capacity, and oil-binding capacity) were exhibited by them. These properties enabled hierarchical cluster analysis and principal component analysis to group the byproducts into 3 different clusters by functionality and from this, assigned ingredients in each cluster to a potential end-uses. Some end use examples include, as a source of fat, protein, sugar, and insoluble fiber; and for uses as a thickening agent, water-binder, emulsion-enhancer, and fat-binder.

PRACTICAL APPLICATION

The data presented in this study can be used by food manufacturers and product developers as the basis for choosing fiber-rich byproducts for specific applications and assist them in developing specific formulation and processing strategies. This characterization will reduce the time for development of fiber-rich foods, increasing industrial uses of byproducts, and decreasing food waste.

Capillary liquid chromatography-ion trap-mass spectrometry methodology for the simultaneous quantification of four angiotensin-converting enzyme-inhibitory peptides in Prunus seed hydrolysates

Prunus genus fruit seeds are sources of highly angiotensin-I-converting enzyme (ACE)-inhibitory peptides. The presence of peptides IYSPH, IYTPH, IFSPR, and VAIP seems to be related to this activity but no previous work has demonstrated the direct relationship between the concentration of these peptides and the antihypertensive activity of hydrolysates. This work describes the development of a method for the quantification of these peptides in Prunus seeds hydrolysates based on capillary liquid chromatography-IT-MS/MS. The analytical characteristics of the method were evaluated through the study of the linearity, LOD, LOQ, presence of matrix interferences, precision, and recovery. The developed methodology was applied to the determination of the four peptides in seed hydrolysates from different Prunus genus fruits: peaches (7 varieties), plums (2 varieties), nectarines (3 varieties), apricots (2 varieties), cherry, and paraguayo. Peaches and plums seed hydrolysates yielded the highest concentrations of these peptides while paraguayo one showed the lowest concentrations. A high correlation between peptides concentrations was demonstrated suggesting that the four peptides could be released from the same seed proteins.

The Potential and Action Mechanism of Polyphenols in the Treatment of Liver Diseases

Liver disease, involving a wide range of liver pathologies from fatty liver, hepatitis, and fibrosis to cirrhosis and hepatocellular carcinoma, is a serious health problem worldwide. In recent years, many natural foods and herbs with abundant phytochemicals have been proposed as health supplementation for patients with hepatic disorders. As an important category of phytochemicals, natural polyphenols have attracted increasing attention as potential agents for the prevention and treatment of liver diseases. The striking capacities in remitting oxidative stress, lipid metabolism, insulin resistance, and inflammation put polyphenols in the spotlight for the therapies of liver diseases. It has been reported that many polyphenols from a wide range of foods and herbs exert therapeutic effects on liver injuries via complicated mechanisms. Therefore, it is necessary to have a systematical review to sort out current researches to help better understand the potentials of polyphenols in liver diseases. In this review, we aim to summarize and update the existing evidence of natural polyphenols in the treatment of various liver diseases by in vitro, in vivo, and clinical studies, while special attention is paid to the action mechanisms.

Apricot and other seed stones: amygdalin content and the potential to obtain antioxidant, angiotensin I converting enzyme inhibitor and hypocholesterolemic peptides

Stones from olives and Prunus genus fruits are cheap and sustainable sources of proteins and could be potential sources of bioactive peptides. The main limitation to the use of these seeds is the presence of amygdalin. This work proposes to determine amygdalin in olive and Prunus seeds and in protein isolates obtained from them. Moreover, antioxidant, angiotensin I converting enzyme (ACE) inhibitor, and hypocholesterolemic properties will be evaluated in hydrolysates obtained from these seeds. Despite some seeds contained amygdalin, all protein isolates were free of this substance. Two different procedures to obtain bioactive peptides from protein isolates were examined: gastrointestinal digestion and processing with Alcalase, Flavourzyme or Thermolysin. Higher antioxidant, ACE inhibitor and hypocholesterolemic activities were observed when proteins were processed with Alcalase, Flavourzyme or Thermolysin. The highest antioxidant and ACE inhibitor capacities were observed for the Prunus genus seed hydrolysates while the highest capacity to reduce micellar cholesterol solubility was observed for the apricot and olive seed hydrolysates.

Simultaneous optimization of ultrasonic-assisted extraction of antioxidant and anticoagulation activities of compounds from Leonurus japonicus Houtt. by response surface methodology

Leonurus japonicus Houtt. is a herbaceous annual of the Lamiaceae family with pantropical distribution; it is called motherwort in China. It plays important roles in anticoagulation and antioxidation. This study aimed to explore the optimization of ultrasound-assisted extraction of multiple compounds from motherwort as well as their antioxidant and anticoagulation activities using response surface methodology. Box–Behnken design was employed to optimize three significant influences, namely extraction time, extraction temperature and ethanol concentration. The optimum extraction parameters acquired based on a combination of the yield of the target compounds and their antioxidant and anticoagulation activities were an extraction time of 38.2 min, an extraction temperature of 30.0 °C, an ethanol concentration of 48.9% (v/v), a solid–liquid ratio of 30.0 mL g⁻¹ and an ultrasonic power of 500.0 W. Under the optimal conditions, the maximal yield of the anticoagulation and antioxidant compounds of motherwort was 0.994%; the thrombin time was 19.872 s; prothrombin time was 8.270 s; the activated partial thromboplastin time was 15.535 s; the fibrinogen was 1.420 g L⁻¹; and the 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity was 1.503 mg mL⁻¹. The optimized conditions model showed a good correlation between the predicted and experimental values. According to the results of our study, the optimization extraction significantly enabled study of the anticoagulation and antioxidant activities of compounds in motherwort; this may contribute to future research on the pharmacological activities of motherwort.

Leonurus japonicus Houtt. is a herbaceous annual of the Lamiaceae family with pantropical distribution; it is called motherwort in China.

Organic Acids, Antioxidants, and Dietary Fiber of Mexican Blackberry (Rubus fruticosus) Residues cv. Tupy

Blackberry fruit processing generates residues comprised of peel, seeds, and pulp that are abundant in flavonoids, colorants, and organic acids. The objective of this study was to determine the organic acids, antioxidants, and dietary fiber content of blackberry residues and compare antioxidants and dietary fiber content of a prune-based commercial product. The ABTS, DPPH, and FRAP methodologies were used for antioxidant capacity. The blackberry residues exhibited a high amount of malic acid (5706.37 mg/100 g db), phenols (4016.43 mg GAE/100 g db), and anthocyanins content (364.53 mg/100 g db) compared with the commercial product. These compounds contributed to the antioxidant capacity (by ABTS) of both products but were 20 times higher in blackberry residues. The fruit residues were able to reduce iron (by FRAP) 4.4 times compared to the prune-based product. Total dietary fiber (44.26%) and functional properties as water retention capacity (2.94 g/g), swelling capacity (5.00 mL/g), and fat absorption capacity (1.98 mL/g) of blackberry residues were significantly higher than those of the commercial sample. The results demonstrated that, due to its antioxidant compounds and functional properties, the blackberry residue can be considered a source of components with potential benefit to human health.

Optimization of the antioxidant polyphenolic compounds extraction of yellow passion fruit seeds (Passiflora edulis Sims) by response surface methodology

The conditions for the solid-liquid extraction of the antioxidant polyphenol compounds from yellow passion fruit seeds were optimized by response surface methodology with the following variables as the extraction parameters: extraction time (12.8-147.2 min), ethanol concentration (13-97%), and temperature (16.4-83.6 °C). The polyphenol content and antioxidant capacity, which were assessed by the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, oxygen radical absorbance capacity, β-carotene bleaching assay, and ferric reducing antioxidant power assay, were considered dependent variables. The association of the dependent variables was effective for explaining the effect of the independent variables within a determination coefficient (R²) range of 0.88-0.96. A moderate-to-strong correlation for the polyphenol content and antioxidant capacity by the investigated methods was established, and optimized conditions were employed to maximize this response. Extraction was carried out at 80 °C using 70% ethanol concentration for 30 min, which was the most efficient condition to obtain an extract with high concentrations of polyphenolic compounds (3.12 g gallic acid equivalent/100 g seed dry basis) and a strong antioxidant capacity. The stilbene piceatannol was the major compound identified by liquid chromatography-electrospray ionization-tandem mass spectrometry (3.68 g/100 g seed dry basis). These results reinforce that agro-industrial waste demonstrates potential as a source of bioactive compounds, with implications in human health as well as in food and chemical industries.

Effects and Mechanisms of Fruit and Vegetable Juices on Cardiovascular Diseases

Many studies have indicated that consumption of vegetables and fruits are positively related to lower incidence of several chronic noncommunicable diseases. Although composition of fruit and vegetable juices is different from that of the edible portion of fruits and vegetables, they contain polyphenols and vitamins from fruits and vegetables. Drinking vegetable and fruit juices is very popular in many countries, and also an efficient way to improve consumption of fruits and vegetables. The studies showed that fruit and vegetable juices affect cardiovascular risk factors, such as lowering blood pressure and improving blood lipid profiles. The main mechanisms of action included antioxidant effects, improvement of the aspects of the cardiovascular system, inhibition of platelet aggregation, anti-inflammatory effects, and prevention of hyperhomocysteinemia. Drinking juices might be a potential way to improve cardiovascular health, especially mixtures of juices because they contain a variety of polyphenols, vitamins, and minerals from different fruits and vegetables. This review summarizes recent studies on the effects of fruit and vegetable juices on indicators of cardiovascular disease, and special attention is paid to the mechanisms of action.

Natural Antioxidants in Foods and Medicinal Plants: Extraction, Assessment and Resources

Natural antioxidants are widely distributed in food and medicinal plants. These natural antioxidants, especially polyphenols and carotenoids, exhibit a wide range of biological effects, including anti-inflammatory, anti-aging, anti-atherosclerosis and anticancer. The effective extraction and proper assessment of antioxidants from food and medicinal plants are crucial to explore the potential antioxidant sources and promote the application in functional foods, pharmaceuticals and food additives. The present paper provides comprehensive information on the green extraction technologies of natural antioxidants, assessment of antioxidant activity at chemical and cellular based levels and their main resources from food and medicinal plants.

Bioactives from fruit processing wastes: Green approaches to valuable chemicals

Fruit processing industries contribute more than 0.5billion tonnes of waste worldwide. The global availability of this feedstock and its untapped potential has encouraged researchers to perform detailed studies on value-addition potential of fruit processing waste (FPW). Compared to general food or other biomass derived waste, FPW are found to be selective and concentrated in nature. The peels, pomace and seed fractions of FPW could potentially be a good feedstock for recovery of bioactive compounds such as pectin, lipids, flavonoids, dietary fibres etc. A novel bio-refinery approach would aim to produce a wider range of valuable chemicals from FPW. The wastes from majority of the extraction processes may further be used as renewable sources for production of biofuels. The literature on value addition to fruit derived waste is diverse. This paper presents a review of fruit waste derived bioactives. The financial challenges encountered in existing methods are also discussed.

Extraction and quantification of polyphenols from kinnow (Citrus reticulate L.) peel using ultrasound and maceration techniques

An investigation was carried out to extract polyphenols from the peel of kinnow (Citrus reticulate L.) by maceration and ultrasound-assisted extraction (UAE) techniques. The antioxidant potential of these polyphenols was evaluated using ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and superoxide radical scavenging assays; and their antimicrobial activity was assessed against bacterial strains Staphyloccoccus aureus, Bacillus cereus, and Salmonella typhimurium. The highest extraction yield was obtained through the solvent ethanol at 80% concentration level, whereas UAE was a more efficient technique and yielded comparatively higher polyphenol contents than maceration. Maximum polyphenols were extracted with 80% methanol [32.48 mg gallic acid equivalent (GAE)/g extract] using UAE, whereas minimum phenolics (8.64 mg GAE/g extract) were obtained with 80% ethyl acetate through the maceration technique. Elevated antioxidant activity of kinnow peel extracts was exhibited in three antioxidant assays, where 80% methanolic extracts showed the highest antioxidant activity (27.67 ± 1.11mM/100 g for FRAP) and the highest scavenging activity, 72.83 ± 0.65% and 64.80 ± 0.91% for DPPH and superoxide anion radical assays, respectively. Strong correlations between total polyphenols and antioxidant activity were recorded. Eleven phenolic compounds—including five phenolic acids and six flavonoids—were identified and quantified by high performance liquid chromatography. Ferulic acid and hesperidin were the most abundant compounds whereas caffeic acid was the least abundant phenolic compound in kinnow peel extracts. Maximum inhibition zone was recorded against S. aureus (16.00 ± 0.58 mm) whereas minimum inhibition zone was noted against S. typhimurium (9.00 ± 1.16 mm). It was concluded that kinnow mandarin peels, being a potential source of phenolic compounds with antioxidant and antimicrobial properties, may be used as an ingredient for the preparation of functional foods.

Ultrasound-assisted extraction of natural antioxidants from the flower of Limonium sinuatum: Optimization and comparison with conventional methods

Natural antioxidants are widely used as dietary supplements or food additives. An optimized method of ultrasound-assisted extraction (UAE) was proposed for the effective extraction of antioxidants from the flowers of Limonium sinuatum and evaluated by response surface methodology. In this study, ethanol concentration, ratio of solvent to solid, ultrasonication time and temperature were investigated and optimized using a central composite rotatable design. The optimum extraction conditions were as follows: ethanol concentration, 60%; ratio of solvent to solid, 56.9:1mL/g; ultrasonication time, 9.8min; and temperature, 40°C. Under the optimal UAE conditions, the experimental values (483.01±15.39μmolTrolox/gDW) matched with those predicted (494.13μmolTrolox/gDW) within a 95% confidence level. In addition, the antioxidant activities of UAE were compared with those of conventional maceration and Soxhlet extraction methods, and the ultrasound-assisted extraction could give higher yield of antioxidants and markedly reduce the extraction time.

Bioactivities and Health Benefits of Wild Fruits

Wild fruits are exotic or underutilized. Wild fruits contain many bioactive compounds, such as anthocyanins and flavonoids. Many studies have shown that wild fruits possess various bioactivities and health benefits, such as free radical scavenging, antioxidant, anti-inflammatory, antimicrobial, and anticancer activity. Therefore, wild fruits have the potential to be developed into functional foods or pharmaceuticals to prevent and treat several chronic diseases. In the present article, we review current knowledge about the bioactivities and health benefits of wild fruits, which is valuable for the exploitation and utilization of wild fruits.

Effects of 20 Selected Fruits on Ethanol Metabolism: Potential Health Benefits and Harmful Impacts

The consumption of alcohol is often accompanied by other foods, such as fruits and vegetables. This study is aimed to investigate the effects of 20 selected fruits on ethanol metabolism to find out their potential health benefits and harmful impacts. The effects of the fruits on ethanol metabolism were characterized by the concentrations of ethanol and acetaldehyde in blood, as well as activities of alcohol dehydrogenase and acetaldehyde dehydrogenase in liver of mice. Furthermore, potential health benefits and harmful impacts of the fruits were evaluated by biochemical parameters including aspartate transaminase (AST), alanine transferase (ALT), malondialdehyde, and superoxide dismutase. Generally, effects of these fruits on ethanol metabolism were very different. Some fruits (such as Citrus limon (yellow), Averrhoa carambola, Pyrus spp., and Syzygium samarangense) could decrease the concentration of ethanol in blood. In addition, several fruits (such as Cucumis melo) showed hepatoprotective effects by significantly decreasing AST or ALT level in blood, while some fruits (such as Averrhoa carambola) showed adverse effects. The results suggested that the consumption of alcohol should not be accompanied by some fruits, and several fruits could be developed as functional foods for the prevention and treatment of hangover and alcohol use disorder.

Dietary Natural Products for Prevention and Treatment of Liver Cancer

Liver cancer is the most common malignancy of the digestive system with high death rate. Accumulating evidences suggests that many dietary natural products are potential sources for prevention and treatment of liver cancer, such as grapes, black currant, plum, pomegranate, cruciferous vegetables, French beans, tomatoes, asparagus, garlic, turmeric, ginger, soy, rice bran, and some edible macro-fungi. These dietary natural products and their active components could affect the development and progression of liver cancer in various ways, such as inhibiting tumor cell growth and metastasis, protecting against liver carcinogens, immunomodulating and enhancing effects of chemotherapeutic drugs. This review summarizes the potential prevention and treatment activities of dietary natural products and their major bioactive constituents on liver cancer, and discusses possible mechanisms of action.

Antioxidant Phytochemicals for the Prevention and Treatment of Chronic Diseases

Overproduction of oxidants (reactive oxygen species and reactive nitrogen species) in the human body is responsible for the pathogenesis of some diseases. The scavenging of these oxidants is thought to be an effective measure to depress the level of oxidative stress of organisms. It has been reported that intake of vegetables and fruits is inversely associated with the risk of many chronic diseases, and antioxidant phytochemicals in vegetables and fruits are considered to be responsible for these health benefits. Antioxidant phytochemicals can be found in many foods and medicinal plants, and play an important role in the prevention and treatment of chronic diseases caused by oxidative stress. They often possess strong antioxidant and free radical scavenging abilities, as well as anti-inflammatory action, which are also the basis of other bioactivities and health benefits, such as anticancer, anti-aging, and protective action for cardiovascular diseases, diabetes mellitus, obesity and neurodegenerative diseases. This review summarizes recent progress on the health benefits of antioxidant phytochemicals, and discusses their potential mechanisms in the prevention and treatment of chronic diseases.

Optimization of Ultrasound-Assisted Extraction of Natural Antioxidants from Sugar Apple (Annona squamosa L.) Peel Using Response Surface Methodology

Sugar apple (Annona squamosa L.) is a popular tropical fruit and its peel is a municipal waste. An ultrasound-assisted extraction method was developed for the recovery of natural antioxidants from sugar apple peel. Central composite design was used to optimize solvent concentration (13.2%–46.8%), ultrasonic time (33.2–66.8 min), and temperature (43.2–76.8 °C) for the recovery of natural antioxidants from sugar apple peel. The second-order polynomial models demonstrated a good fit of the quadratic models with the experimental results in respect to total phenolic content (TPC, R² = 0.9524, p < 0.0001), FRAP (R² = 0.9743, p < 0.0001), and TEAC (R² = 0.9610, p < 0.0001) values. The optimal extraction conditions were 20:1 (mL/g) of solvent-to-solid ratio, 32.68% acetone, and 67.23 °C for 42.54 min under ultrasonic irradiation. Under these conditions, the maximal yield of total phenolic content was 26.81 (mg GA/g FW). The experimental results obtained under optimal conditions agreed well with the predicted results. The application of ultrasound markedly decreased extraction time and improved the extraction efficiency, compared with the conventional methods.

Immunostimulatory activity of snake fruit peel extract on murine macrophage-like J774.1 cells

Snake fruit (Salacca edulis Reinw.) is a tropical fruit produced in Indonesia. Snake fruit peel is normally discarded as waste. In the present study, it was revealed that snake fruit peel has high bioactivities on stimulation of the immune system. Snake fruit peel extract (SFPE) was prepared by extracting snake fruit peel powder in water for 15 h at 4 °C. SFPE enhanced phagocytotic activity of murine macrophage-like J774.1 cells. Production of cytokine such as tumour necrosis factor (TNF)-α and interleukin (IL)-6 was also stimulated by SFPE. The gene expression levels for these cytokines were elevated. Immunoblot analysis revealed that SFPE enhanced not only nuclear factor (NF)-κB but also mitogen-activated protein kinases signalling cascades such as JNK and p38 in macrophage. Overall findings suggested that SFPE has a potential beneficial effect to promote our body health through the stimulation of macrophage.

Resources and biological activities of natural polyphenols

The oxidative stress imposed by reactive oxygen species (ROS) plays an important role in many chronic and degenerative diseases. As an important category of phytochemicals, phenolic compounds universally exist in plants, and have been considered to have high antioxidant ability and free radical scavenging capacity, with the mechanism of inhibiting the enzymes responsible for ROS production and reducing highly oxidized ROS. Therefore, phenolic compounds have attracted increasing attention as potential agents for preventing and treating many oxidative stress-related diseases, such as cardiovascular diseases, cancer, ageing, diabetes mellitus and neurodegenerative diseases. This review summarizes current knowledge of natural polyphenols, including resource, bioactivities, bioavailability and potential toxicity.