Reutilization of mango byproducts: study of the effect of extraction solvent and temperature on their antioxidant properties

Mango biowastes, obtained after processing, contain large amounts of compounds with antioxidant activity that can be reused to reduce their environmental impact. The present study evaluates the effect of solvent (methanol, ethanol, acetone, water, methanol:water [1:1], ethanol:water [1:1], and acetone:water [1:1]), and temperature (25, 50, and 75 °C) on the efficiency of the extraction of antioxidants from mango peel and seed. Among the factors optimized, extraction solvent was the most important. The solvents that best obtained extracts with high antioxidant capacity were methanol, methanol:water, ethanol:water, and acetone:water (β-carotene test, antioxidant activity coefficient 173 to 926; thiobarbituric acid reactive substances test, inhibition ratio 15% to 89%; 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid ABTS(·+); and 2,2-diphenyl-1-picrylhydrazyl DPPH· scavenging, 7 to 22 and 8 to 28 g trolox equivalent antioxidant capacity [TE] per 100 g mango biowaste on a dry matter basis [DW]). Similarly, the flavonoid (0.21 to 1.4 g (+)-catechin equivalents per 100 g DW), tannin (3.8 to 14 g tannic acid equivalents per 100 g DW), and proanthocyanidin (0.23 to 7.8 g leucoanthocyanidin equivalents per 100 g DW) content was highest in the peel extracts obtained with methanol, ethanol:water, or acetone:water and in the seed extracts obtained with methanol or acetone:water. From the perspective of food security, it is advisable to choose ethanol (which also has a notable antioxidant content), ethanol:water, or acetone:water, as they are all solvents that can be used in compliance with good manufacturing practice. In general, increasing temperature improves the capacity of the extracts obtained from mango peel and seed to inhibit lipid peroxidation; however, its effect on the extraction of phytochemical compounds or on the capacity of the extracts to scavenge free radicals was negligible in comparison to that of the solvent. PRACTICAL APPLICATION: There are many antioxidant compounds in mango peel and seed, and they could be used as a natural and very inexpensive alternative to synthetic food additives. However, the conditions in which the antioxidants are extracted must be optimized. This work proves that conditions such as extraction solvent or temperature have a crucial impact on obtaining extracts rich in antioxidants from mango biowastes.     

Phenolic compounds and antioxidant activity of seed and skin extracts of red grape (Vitis vinifera and Vitis labrusca) pomace from Brazilian winemaking

The phenolic compounds content and antioxidant activity of seed and skin of pomace from the vinification of grape varieties widely produced in Brazil were investigated with a view to their exploitation as a potential source of natural antioxidants. There was a greater concentration of phenolic compounds in the seeds (2128 to 16,518 mg of catechin equivalents (CE)/100 g) than in the skins (660 to 1839 mg CE/100 g). The highest antioxidant activity values determined as DPPH radical-scavenging ability and ferric reducing-antioxidant power (FRAP) were found for the seeds of the Pinot Noir variety (16,925 ??mol Trolox equivalents (TE)/100 g and 21,492 ??mol Fe²⁺/100 g, respectively) and in the skin extracts of the Isabel variety (3640 ??mol TE/100 g and 4362 ??mol Fe²⁺/100 g, respectively). The skin of Cabernet Sauvignon and Primitivo varieties had the highest contents of anthocyanins (935 and 832 mg/100 g, respectively). The grape seed extracts were rich in oligomeric and polymeric flavanols. The data suggested that grape seed and skin extracts may be exploited as antioxidant agents.     

HPLC profiling of phenolics in diverse potato genotypes

Potatoes from over fifty genotypes representing cultivars, breeding lines, primitive germplasm and wild species were analysed for phenolic content and hydrophilic antioxidant capacity. Genotypes with markedly higher amounts than the most commonly consumed potatoes were identified. Chlorogenic acid was the most abundant phenolic and ranged from 22 to 473 mg/100 g dry weight. Rutin and kaempferol-3-rutinose were the most abundant flavonols. Total phenolics ranged from 1.8 to 11 mg/g DW and antioxidant capacity ranged from 27 to 219 μmol TE/g DW. Total phenolics and antioxidants in these high-phytonutrient potatoes compared favourably to 15 other analysed vegetables. With the high per capita consumption of potatoes, widespread adoption of high-phytonutrient cultivars could significantly increase dietary intake of phytonutrients.     

Autoxidation of methyl linolenate. The effect of antioxidants on product distribution

Studies on autoxidation of polyunsaturated fatty acids in the presence of antioxidants have shown that there can be significant differences in the proportions and types of products produced in ‘inhibited’ autoxidations, as compared with control autoxidations, in the absence of an antioxidant. The autoxidation of methyl linolenate has been used as a model system with which to study the effects of different concentrations of both natural and synthetic antioxidants on the proportions of the various types of oxidation product formed. The antioxidants studied included α-, γ-, and δ-tocopherol, α-tocotrienol, 2,2,5,7,8-pentamethylhydroxychroman (PMHC), 2,6-di-tert-butyl-4-methylphenol (BHT), 3-tert-butyl-4-hydroxyanisole (BHA), and mono-tert-butylhydroquinone (TBHQ). In order to investigate the effect of the antioxidants, the oxidation products were analysed for the proportions of diperoxides and monohy-droperoxides present, and the monohydroperoxide class was further analysed for the proportions of cis, trans and trans, trans dienes and ‘inner’ and ‘outer’ hydroperoxides. In all cases where any significant oxidation occurred the extent of the change in product distribution caused by the antioxidant increased as the antioxidant concentration increased. In many cases the extent of methyl linolenate oxidation occurring under standard conditions (after 100 h at 40°C) also increased as the antioxidant concentration increased, but this was not so for δ-tocopherol, BHT and TBHQ. The importance of these findings in relation to food systems and to the understanding of antioxidant behaviour is discussed.     

Flavonoids profile and antioxidant activity in flowers and leaves of hawthorn species (Crataegus spp.) from different regions of Iran

This study was undertaken to determine the total quantity of phenolic and flavonoids, as well as to find out about the HPLC quantification of some individual phenolic compounds (i.e. chlorogenic acid, vitexin 2”-O-rhamnoside, vitexin, rutin, hyperoside, quercetin, and isoquercetin) in flowers and leaves of 56 samples of different hawthorn species (Crataegus spp.) collected from different geographical regions of Iran. The amount of total phenolics ranges from 7.21 to 87.73 mg GAE/g in dry weight of the plant, and the total amount of flavonoids varied amongst species and in different plant organs ranging from 2.27 to 17.40 mg/g dry weight. Chlorogenic acid, vitexin, and vitexin 2”-O-rhamnoside were found to be the most abundant phenolic compounds in the extracts of hawthorn leaves. Meanwhile, chlorogenic acid, hyperoside, and rutin were the most abundant phenolic compounds in the extracts of hawthorn flowers in most genotypes. The antioxidant activity widely varied in species and in different organs of each individual plant, ranging from 0.9 to 4.65 mmol Fe⁺⁺/g DW plant, calculated through the ferric-reducing antioxidant power (FRAP) method. Thus, this could provide valuable data for developing breeding strategies and plans; it can also help us in selecting genotypes with high phenolic contents for producing natural antioxidants and other bioactive compounds beneficial for food or the pharmaceutical industries.     

牡丹花水提物对肾素和ACE的双重抑制作用

研究了牡丹花水提物对肾素-血管紧张素系统中两种关键酶肾素和血管紧张素转化酶(ACE)的抑制作用,选取典型的牡丹花色品种,并与芍药进行比较,考察了样品水提物的肾素和ACE抑制活性及抗氧化能力,并分析酚类及黄酮类物质的含量与其功能活性的相关性。结果表明,红色系的牡丹和芍药花水提物具有优良的肾素和ACE抑制活性,而白色系的牡丹花水提物抑制肾素和ACE活性的能力则很弱。其中活性最高的样品水提物抑制肾素的IC50值为0.08 mg/mL,抑制ACE的IC50值为0.23 mg/mL;此外,红色系的牡丹和芍药花水提物的ABTS自由基清除能力为115.89~121.75mgTE/gDW,DPPH自由基清除能力为192.67~200.46mg TE/g DW,铁离子还原能力为119.86~208.94 mg TE/g DW,总酚含量为99.29~122.45 mg GAE/g DW,白色牡丹花水提物的抗氧化能力及总酚含量均远低于红色系样品水提物。相关性分析表明,不同样品水提物的肾素和ACE抑制活性及DPPH、ABTS自由基清除能力和铁离子还原能力与总酚含量显著正相关(p<0.01),相关系数分别为0.99、0.91、0.99、0.99和0.98。本研究指出深色系的牡丹花水提物倾向于表现出更强的肾素和ACE抑制活性,其中酚类化合物是潜在的重要活性物质,这可为探讨新型血压调控因子及实现不同品系牡丹花的高值化利用提供更丰富的基础理论支撑。     

Flavonoids and Antioxidant Capacity of Various Cabbage Genotypes at Juvenile Stage

ABSTRACT: Ten fresh cabbage genotypes ( Brassica oleraceavar capitata ) representing fresh-market, processing, and storage types were evaluated for total phenols, antioxidant capacity, and flavonoids at the 3-wk juvenile stage, at which time plants are uniform in size when grown under identical soil and environmental conditions. The genotypes studied, 'Bobcat,'Fresco,'Little Rock,'Marvelon,'Rinda,'Ramada,'Transam,'Genesee,'Huron,' and 'Octoking,' showed significant variations in concentration of phenolic phytochemicals and antioxidant capacity. Total phenols ranged from 110.2 mg gallic acid equivalents/100g in 'Genesee' to 153.3 mg gallic acid equivalents/100 g in 'Bobcat'. Total antioxidant capacity varied from 108.4 to 176.1 mg vitamin C equivalents/100 g, and flavonoids from nondetectable to 2.61 mg quercetin/100 g and from 1.30 to 7.03 mgkaempferol/100 g. Apigenin, luteolin, and myricetin were not detected. Five nutritional soil supplements from agricultural and food processing sources (quer-cetin flavonoid complex, commercial vegetable juice, crushed onion, crushed garlic, and green tea) were added to the cabbage genotype 'Rinda' once a week for 3 wk to assess their efficacy in increasing phenolic concentrations in cabbage leaves. Addition of the supplements generally resulted in increased levels of total phenols (97% with commercial vegetable juice), antioxidant capacity (41% with crushed onion), and quercetin plus kaempferol (110% with commercial vegetable juice) in the juvenile 'Rinda' plants with no significant increase with the addition of green tea. Nutritional soil supplements could provide enhanced levels of bioactive phenolic compounds as antioxidants in cabbage and therefore to consumers.     

Determination of Anthocyanins, Total Phenolic Content, and Antioxidant Activity in Andes Berry (Rubus glaucus Benth)

ABSTRACT:  Anthocyanins, total phenolic content, ascorbic acid content, and the antioxidant activity were determined in extracts of Andes berry fruit ( Rubus glaucus Benth). Anthocyanis (ACNs) were isolated and characterized by means of high-performance liquid chromatography (HPLC) with photodiode array detection and electro spray ionization/mass spectrometry (PDA-ESI/MS/MS) analysis. The anthocyanin (ACN) content was 45 mg/100 g FW. The isolated anthocyanins were characterized as cyanidin 3-sambubioside, cyanidin 3-glucoside, cyanidin 3-xylorutinoside, cyanidin 3-rutinoside, pelargonidin 3-glucoside, and pelargonidin 3-rutinoside. The ascorbic acid content was 10.1 mg/100 g FW. The total phenolic content as determined by the Folin–Ciocalteau method was 294 mg GAE/100 g FW while the antioxidant activity as measured by ABTS ^{· +} radical scavenging capacity and ferric reducing antioxidant power (FRAP) was 2.01 and 4.50 mmol TE/100 g FW or 8.22 mmoles ferric iron reduced/100 g FW, respectively. The high phenolic content and antioxidant capacity of Andes berry suggest that this fruit could be a rich source of natural pigments, nutraceuticals, and natural antioxidants.     

Antioxidant capacities of phenolic compounds and tocopherols from Tunisian pomegranate (Punica granatum) fruits

This article aims to determine the phenolic, tocopherol contents, and antioxidant capacities from fruits (juices, peels, and seed oils) of 6 Tunisian pomegranate ecotypes. Total anthocyanins were determined by a differential pH method. Hydrolyzable tannins were determined with potassium iodate. The tocopherol (α-tocopherol, γ-tocopherol, and δ-tocopherol) contents were, respectively, 165.77, 107.38, and 27.29 mg/100 g from dry seed. Four phenolic compounds were identified and quantified in pomegranate peel and pulp using the high-performance liquid chromatography/ultraviolet method: 2 hydroxybenzoic acids (gallic and ellagic acids) and 2 hydroxycinnamic acids (caffeic and p-coumaric acids). Juice, peel, and seed oil antioxidants were confirmed by ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) methods. The highest values were recorded in peels with 25.63 mmol trolox equivalent/100 g and 22.08 mmol TE/100 g for FRAP and ORAC assay, respectively. Results showed that the antioxidant potency of pomegranate extracts was correlated with their phenolic compound content. In particular, the highest correlation was reported in peels. High correlations were also found between peel hydroxybenzoic acids and FRAP ORAC antioxidant capacities. Identified tocopherols seem to contribute in major part to the antioxidant activity of seed oil. The results implied that bioactive compounds from the peel might be potential resources for the development of antioxidant function dietary food.     

Effects of different polarity of onion skin extracts on antioxidative properties and non-volatile profiles

Onion skins are agricultural by-products that contain high levels of antioxidants, including quercetin and protocatechuic acid. The solubility of extracts can affect their antioxidant capacity in food oil matrices. The antioxidative properties of onion skin extracts with different polarity were compared and the chemical profiles of the extracts were identified by GC-MS. Highly lipophilic, moderately hydrophilic and highly hydrophilic onion skin extracts (HLE, MHE and HHE, respectively) were prepared and their antioxidant properties were tested using in vitro assays and bulk oil or oil-in-water (O/W) emulsions. The most abundant phenolic compounds in the onion skin extracts were quercetin and protocatechuic acid. The lipophilicity levels of HLE, MHE and HHE were 0.674, 0.394 and −1.225, respectively. HLE showed higher antioxidant capacity in bulk oil and O/W emulsion matrices compared to MHE and HHE. The antioxidant capacity of HLE was higher in the O/W emulsion than in the bulk oil system. Therefore, highly lipophilic onion skin extracts can be used as effective natural antioxidants in oil matrices, especially O/W emulsions.     

A comprehensive study of polyphenols contents and antioxidant potential of 39 widely used spices and food condiments

Spices and condiments are rich sources of potent antioxidants. In the present investigation, total equivalent antioxidant capacities (TEAC) of 39 spices were studied using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) scavenging, and cupric reducing antioxidant capacity (CUPRAC) assays. Their total phenolic contents (TPC) and total flavonoid contents (TFC) were also determined. TEAC, TPC, and TFC varied significantly (P?<?0.05) among these spices. ABTS, DPPH, and CUPRAC assay values of studied spices ranged from 1.42 to 112.94 mg ascorbic acid equivalents (AAE)/g, 1.14 to 91.09 mg Trolox equivalents (TE)/g, and 0.52 to 54.47 mg TE/g, respectively (dry weight basis; DW). Based on Folin–Ciocalteu assay, TPC ranged from 2.93 to 160.55 mg of gallic acid equivalents (GAE)/g DW. Strong correlations between TPC and TEAC values (R?=?0.966, 0.825, and 0.954 for ABTS, DPPH, and CUPRAC, respectively) were found. This indicates that phenolic compounds are potent antioxidants in these spices. Principal component analysis (PCA) indicated that cloves (flower buds of Syzygium aromaticum) had the most distinct and potent antioxidant capacity, followed by allspice (fruits of Pimenta dioica) and cinnamon (bark of Cinnamomum verum). Results of the present study provide adequate evidence that polyphenols are responsible for their compelling antioxidant capacities of studied spices. Thus, consumption of antioxidant-rich spices such as cloves, allspice, and cinnamon can significantly prevent oxidative stress in the human body.     

Preliminary characterisation of cornelian cherry (Cornusmas L.) genotypes for their physico-chemical properties

Fruit weight, antioxidant capacity, total anthocyanins, total phenolics, ascorbic acid, soluble solid content (SSC), reducing sugar and acidity of a number of selected cornelian cherry (Cornusmas L.) genotypes of varied pigmentation were investigated. Two methods, namely β-carotene bleaching and ferric reducing antioxidant power (FRAP) were used to determine total antioxidant capacity, while Folin–Ciocalteu reagent was used to determine total phenols. Fruit weight, SSC and ascorbic acid content of genotypes were 2.09–9.17; 12.53–21.17% and 29–112 mg/100 g, respectively. Antioxidant activity and total phenolic content varied among genotypes and 44-18 genotype had the highest antioxidant capacity using both methods. This genotype also had the highest total phenolic (74.8 mg GAE/g DW) and total anthocyanin (115 mg cyanidin-3-glucoside equivalents /100 g FW) content. There are linear relationships between antioxidant capacities and total phenols. The present study demonstrates the potential of certain cornelian cherry genotypes, notably 44-18, for improvement of nutritional value through germplasm enhancement programmes.     

Microwave‐assisted extraction in goji berries: effect on composition and bioactivity,evaluated through conventional and nonconventional methodologies

This study aimed to evaluate the effect of microwave‐assisted extraction (MAE) parameters on the composition and bioactivity of goji (Lycium barbarum) extracts. Extracts were obtained under a central composite design combination of experimental conditions, and characterised through HPLC‐DAD; their bioactive capacity was ascertained for antimicrobial and antioxidant capacity, the later by spectrophotometric [2,2‐azinobis (3‐ ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt‐radical scavenging activity assay – 413–748 mg ascorbic acid equivalents/100 g DW and oxygen radical absorbance capacity – 1901–2292 mg trolox equivalents/100 g DW] and electrochemical (DNA‐based sensor – 3571–6602 mg ascorbic acid/100 g DW) methods. The quantitative profile of phenolic compounds was strongly dependent on MAE conditions. Significant correlations were found between the presence of several flavonoids and solvent composition, as well as between phenolic acids with methoxy group and the response to DNA‐based sensor. Results may improve targeted extractions for specific compounds, leading to the achievement of extracts richer in antioxidant capacity, as well as in the tailoring of the biosensor response sensitivity to the composition of the extracts under analysis.     

Fatty acid composition,oxidative stability,antioxidant and antiproliferative properties of selected cold-pressed grape seed oils and flours

Cold-pressed chardonnay, muscadine, ruby red, and concord grape seed oils and their defatted flours were studied for their fatty acid composition, oxidative stability and antioxidant and antiproliferative activities. The phenolic profiles of the seed flours were also measured. The most abundant fatty acid in the oils was linoleic acid, ranging from 66.0 g/100 g of total fatty acids in ruby red seed oil to 75.3 g/100 g of total fatty acids in concord seed oil. The oils were also high in oleic acid and low in saturated fat. Ruby red grape seed oil recorded the highest oxidative stability index of 40 h under the accelerated conditions. Total phenolic content (TPC) was up to 100 times lower in the oils than in the flours. Lutein, zeaxanthin, cryptoxanthin, β-carotene, and α-tocopherol levels were also measured. DPPH radical-scavenging capacity ranged from 0.07 to 2.22 mmol trolox equivalents (TE)/g of oil and 11.8 to 15.0 mmol TE/g of flour. Oxidative stability of menhaden fish oil containing extracts of the seed flours was extended by up to 137%. HPLC analysis was conducted to determine the levels of free soluble, soluble conjugated and insoluble bound phenolics in the seed flours. The phenolic compounds analyzed included catechin, epicatechin, epicatechin gallate, quercetin, gallic acid, and procyanidins B1 and B2. Antiproliferative activity was tested against HT-29 colon cancer cells. All of the seed flours and muscadine seed oil registered significant (P < 0.05) inhibition of cancer cell growth. The results from this study demonstrate the potential of developing value-added uses for these seed oils and flours as dietary sources of natural antioxidants and antiproliferative agents for optimal health.     

Effects of Extraction Solvents and Provenances on Phenolic Contents and Antioxidant Activities of Cumin (Cuminum cyminum L.) Seeds

Polyphenol contents and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity of cumin (Cuminum cyminum L.) seed extracts were compared depending on their geographical origin (Tunisia and India: TCS and ICS, respectively) and the extraction solvent polarity. The ??-carotene bleaching assay, the chelating ability and the reducing power of the most promising solvent extracts were also assessed. In addition, TCS and ICS extracts were acid-hydrolyzed and the phenolics identified by reversed-phase high-performance liquid chromatography (HPLC). Seed phenolic contents and antioxidant activity appeared to be accession and solvent dependent. Extraction with 80% acetone led to the highest polyphenol (18.60 and 16.50?mg gallic acid equivalents (GAE)/g dry weight (DW)), flavonoid (5.91 and 4.99?mg catechin equivalents (CE)/g DW) and tannin (83.23 and 80.23?mg CE/g DW) contents, respectively for TCS and ICS. DPPH scavenging activity, ??-carotene bleaching assay, chelating ability and reducing power were maximal in 80% acetone for both TCS and ICS. HPLC analysis revealed several phenolic compounds in C. cyminum seeds, with p-coumaric (4.83 and 2.33?mg/g DW), trans-2-dihydrocinnamic (1.09 and 1.20?mg/g DW) and rosmarinic (0.70 and 1.04?mg/g DW) acids as major phenolics in TCS and ICS, respectively. Thus, phenolic composition of cumin seeds is also origin dependent. Taken together, our findings indicate that cumin might constitute a rich and novel source of natural antioxidants as food additives in food industry and that acetone 80% would be the most appropriate solvent for seed extraction.     

Comparison of Antioxidant Activities and High-Performance Liquid Chromatography Analysis of Polyphenol from Different Apple Varieties

Concentration of polyphenols in apples depends on factors such as harvest, cultivar, processing, and storage conditions. We aimed to identify essential polyphenols present in various apple varieties, and measure their free phenol and antioxidant capacities using 1,1-diphenyl-2-picylhydrazyl radical scavenging capacity, oxygen radical absorbance capacity, hydroxyl radical scavenging capacity, and ferric reducing antioxidant power methods, and correlating with the total polyphenol content and antioxidant capacity with high-performance liquid chromatography results. Thirteen apple varieties cultivated in northwest China showed significant polyphenol content. Hongxun 1 had the highest polyphenol content and antioxidant capacities in comparison with other apple varieties, while phlorizin showed the strongest 1,1-diphenyl-2-picylhydrazyl free radical scavenging rate (73.5 ± 2.7%), oxygen radical absorbance capacity value (44.6 ± 3.1 μmol TE/g), hydroxyl radical scavenging capacity value (61.9 ± 3.5 μmol TE/g), and ferric reducing antioxidant power value (0.53 ± 0.37 μmol TE/g). The antioxidant capacities of the polyphenol extract was related not only to its total polyphenol content but also to the phenolic composition.     

The optimisation of solid–liquid extraction of antioxidants from apple pomace by response surface methodology

Response surface methodology using two food grade solvents, acetone and ethanol, was used to optimise antioxidant extraction from industrially generated apple pomace. Efficiency of extraction was optimised by measuring antioxidant activity, phenol content and three individual polyphenol groups. Conditions for optimal antioxidant activity as measured by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay were 56% ethanol, 80 °C and 31 min. Using these conditions an antioxidant value of 444 mg Trolox/100 g DW was obtained. For acetone extraction the optimal conditions were 65% acetone, 25 °C and 60 min, resulting in an antioxidant value of 436 mg Trolox/100 g DW. Both ethanol and acetone would be suitable to replace methanol for a food grade and more environmental friendly solid–liquid extraction of antioxidants.     

Optimization of Antioxidant Compounds Extraction from Flesh of New Developed Apple Cultivar Using Response Surface Methodology

The response surface methodology (RSM) and the central composite rotatable design were used to optimize the antioxidant extraction from apple flesh of a new cultivar (Rural Issues and Agricultural Research Institute of Santa Catarina (EPAGRI) m-58/07). The extraction conditions were optimized by measured antioxidant capacities from the ferric-reducing power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays, and by the determination of total phenol content. The results showed that the most significant variable in the extraction procedure was solvent concentration. The optimal condition found was of 60 %, 5 mL/g, 30 °C, and 61 min for acetone aqueous solution, solvent to solid ratio, temperature, and time, respectively, resulting in optimal antioxidant capacities of 2,152.96 μmol TE/100 g DW by DPPH and 6,491.39 μmol Fe²⁺/100 g DW by FRAP essays, and total phenol amount of 485.62 mg GAE/100 g DW. The antioxidant capacity of EPAGRI m-58/07 was verified to be substantially higher than other cultivars commercially available.     

Physical and antibacterial properties of edible films formulated with apple skin polyphenols

Fruit and vegetable skins have polyphenolic compounds, terpenes, and phenols with antimicrobial and antioxidant activity. These flavoring plant essential oil components are generally regarded as safe. Edible films made from fruits or vegetables containing apple skin polyphenols have the potential to be used commercially to protect food against contamination by pathogenic bacteria. The main objective of this study was to evaluate physical properties as well as antimicrobial activities against Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella enterica of apple skin polyphenols at 0% to 10% (w/w) concentrations in apple puree film-forming solutions formulated into edible films. Commercial apple skin polyphenol powder had a water activity of 0.44 and high total soluble phenolic compounds and antioxidant capacity (995.3 mg chlorogenic acid/100 g and 14.4 mg Trolox/g, respectively). Antimicrobial activities of edible film containing apple skin polyphenols were determined by the overlay method. Apple edible film with apple skin polyphenols was highly effective against L. monocytogenes. The minimum concentration need to inactive L. monocytogenes was 1.5%. However, apple skin polyphenols did not show any antimicrobial effect against E. coli O157:H7 and S. enterica even at 10% level. The presence of apple skin polyphenols reduced water vapor permeability of films. Apple skin polyphenols increased elongation of films and darkened the color of films. The results of the present study show that apple skin polyphenols can be used to prepare apple-based antimicrobial edible films with good physical properties for food applications by direct contact.     

Phenolic Compounds and Plant Phenolic Extracts as Natural Antioxidants in Prevention of Lipid Oxidation in Seafood: A Detailed Review

Lipid oxidation is the principal cause of quality loss in seafood, which is known to contain high amounts of polyunsaturated fatty acids. Such quality deterioration, associated with the development of off‐flavor as well as lowering of nutritive value, can be retarded by incorporation of additives having antioxidative properties. The use of synthetic antioxidants has long been practiced in retarding lipid oxidation. However, due to the potential health concerns of synthetic antioxidants, polyphenolic compounds, which are found in different plants and their manufactured by‐products, have been used as an alternative natural antioxidants to retard lipid oxidation in different seafood systems. Both pure phenolic compounds and crude plant phenolic extracts have been successfully used in delaying oxidation in fish muscle, fish oil, and fish oil‐in‐water emulsions. This article reviews in detail the phenolic antioxidants and their natural sources as well as focuses on the role of pure phenolic compounds and crude plant phenolic extracts on the prevention of lipid oxidation in different seafood systems.