A comparative study on phenolic profile,vitamin C content and antioxidant activity of Italian honeys of different botanical origin

The aim of our study was to identify and quantify the phenolic acids, flavonoids and vitamin C and to evaluate the antioxidant activity in ninety Italian honeys of different botanical origins (chestnut, sulla, eucalyptus, citrus and multifloral). The results showed that total phenolic and flavonoid contents varied from 11.08 to 14.26 mg GAE per 100 g honey and from 5.82 to 12.52 mg QE per 100 g honey, respectively. HPLC–UV analysis showed a similar but quantitatively different phenolic profile of the studied honeys. Vitamin C is present in all samples. Multifloral honey showed the highest amount of the detected total phenolic compounds and the highest vitamin C content. The DPPH value varied from 55.06 to 75.37%. Among the unifloral honeys, chestnut honey presented the highest levels of phenolic acids, flavonoids and vitamin C, which are closely associated with its high antioxidant activity. The results show that honey contains high amount of biologically active compounds, which play an important role in defining the nutraceutical quality of the product, and that the distribution of these compounds is influenced by the botanical origin.     

Phenolic content,antioxidant and physico‐chemical properties of Sardinian monofloral honeys

In this study, fifty‐one monofloral Sardinian honeys from ten various floral origins were screened for their phenolic content, antioxidant activity, colour and electrical conductivity. The total phenolic amounts have been evaluated by Folin–Ciocalteu method, whereas quantification of several phenolic compounds (phenolic acids and flavonoids) has been carried out by HPLC‐DAD technique. The richest sample in phenolic compounds resulted strawberry tree honey with about 40 mg GAE/100 g, as well FRAP test and DPPH˙ test confirm that antioxidant activity of strawberry tree honey extract exceed both honey extracts and synthetic antioxidants like BHA and BHT. Among the studied phenolic compounds a total of five phenolic acids (ferulic, syringic, trans‐cinnamic, chlorogenic and p‐hydroxycinnamic) and nine flavonoids (catechin, kaempferol, rutin, quercetin, luteolin, apigenin, galangin, pinocembrin and pinobanksin) were identified. Our results show good correlations between total polyphenol amount and antioxidant activity and between colour and electrical conductivity.     

Evaluation of physico‐chemical properties,trace metal content and antioxidant activity of Indian honeys

In this study, effect of plant sources viz. Gossypium hirsutum, Coriander sativum, Murraya koenigii and Dalbergia sisso on twelve physico‐chemical properties, phenolic content, flavonoids content as well as on trace mineral (Fe, Cu, Ni, Mn, Cd and Pb) contents of honey were investigated and compared. All the physico‐chemical values were in the range of approved limits of European Commission Regulation and the source of honey had a significant (P < 0.05) effect on physico‐chemical properties, phenol content, flavonoid content and trace mineral content. The results of positive correlations between physico‐chemical properties (colour and antioxidant properties) and compositional components (phenols and flavonoids content) established that antioxidant properties were dependent on source of honey rather than on colour of honey. Pattern recognition methods such as principal component analysis and linear discriminate analysis were performed to classify honey on the basis of physico‐chemical properties, phenolic content, flavonoids content and trace metal content. The variables proline and lead exhibited higher discrimination power.     

Evaluation of the Phenolic Content,Antiradical, Antioxidant,and Antimicrobial Activity of Different Floral Sources of Honey

Thirty-five honeys were evaluated for total phenolic content by Folin-Ciocalteu method, for potential antioxidant activity using phosphomolibdenum assay and by the 1,1-diphenyl-2-picrylhydrazyl method for antiradical activity. The antimicrobial activity was studied by the agar diffusion method, using 12 bacteria and 2 yeasts. The means of the total phenolic contents of chestnut, honeydew, multifloral, thyme, and astragalus were 47 ± 18, 24.2 ± 0.6, 14 ± 11, 11 ± 6, and 9 ± 7 mg/100 g honey as gallic acid equivalent, respectively. The lowest antioxidant activity was observed in honeydew 70 ± 5 mg ascorbic acid equivalent/g honey while the highest content was observed in astragalus honey 86 ± 16 mg ascorbic acid equivalent/g honey. Correlation between the phenolic content and antioxidant activity were found to be statistically significant. Chestnut honeys (n = 5) exhibited maximum free radical scavenging activity with an average 68 ± 9%. The honey samples showed the highest antimicrobial activity against some microorganisms, especially Escherichia coli O157:H7, Salmonella typhimurium, Staphylococcus aureus, Listeria monocytogenes, and Proteus mirabilis. On the other side, Aeromonas hydrophila, Bacillus subtilis, and E. coli were the most resistant microorganisms. The results revealed that the Turkish honeys studied proved to be a good source of antioxidant and antimicrobial agents that might serve to protect human health.     

Antioxidant properties and phenolic content of sulla (Hedysarum spp.) honeys from Southern Italy

The geographical origin greatly influences the qualitative and nutraceutical characteristics of honey. In this study, a total of twenty‐four sulla honeys from eight different geographical areas of Southern Italy have been examined for total phenolic content (Folin–Ciocalteu method), antioxidant activity (FRAP and DPPH assays), colour intensity (ABS₄₅₀), and identification and quantification of phenolic acids (RP‐HPLC/UV‐VIS method). The total phenolic content ranged from 47.9 (Potentino honeys) to 248.3 mg GAE per kg honey (Penisola Sorrentina honeys). The antioxidant activity ranged from 47.06% (Basso Pollino honeys) to 88.25% (Penisola Sorrentina honeys), and from 98.26 μM Fe (II) (Potentino honeys) to 786.53 μm Fe (II) (Tarantino honeys) for DPPH and FRAP assays, respectively. Major phenolic acids identified in analysed samples were gallic, caffeic and ferulic acids. Correlations between the parameters analysed were statistically significant (P < 0.05). The results of the study showed that the parameters studied are greatly affected by the peculiarities of their production area.     

不同蜂蜜抗氧化活性和抑制酪氨酸酶活性的比较

该研究采用分光光度法测定了10种蜂蜜中总酚酸和总黄酮的含量及对酪氨酸酶的活性抑制,采用1,1-二苯基苦基苯肼（DPPH）自由基清除法和铁离子还原（FRAP）法测定了其体外抗氧化活性。结果表明,10种蜂蜜总酚酸含量为116.46~2 133.33 mg PCA/kg,总黄酮含量为8.31~120.81 mg QUE/kg,DPPH自由基清除IC50为16.25~674.22 mg/mL,铁离子还原FRAP值为0.50~7.39 mmol Fe2+/kg,酪氨酸酶抑制IC50为9.15~350.26 mg/mL。荞麦蜜的DPPH自由基清除能力（IC50为16.25~45.83 mg/mL）、铁离子还原能力（3.21~7.39 mmol Fe2+/kg）和酪氨酸酶活性抑制能力（IC50为9.15~14.16 mg/mL）显著高于其他几种蜂蜜（p<0.05）。蜂蜜抗氧化活性、酪氨酸酶抑制活性与蜂蜜中总酚酸、总黄酮含量显著相关（p<0.05）。该研究为蜂蜜功能性产品的开发提供了依据。     

不同种类蜂蜜总酚酸含量测定和抗氧化作用的研究

本文测定了槐花蜜、黄芪蜜、苹果蜜、荞麦蜜、枸杞蜜、山楂蜜、山花蜜、五味子蜜、菊花蜜和油菜蜜等十种蜂蜜的总酚酸含量和抗氧化活性。结果表明,十种蜂蜜的总酚酸含量在13.30±0.92mg/100g蜂蜜到148.46±2.34mg/100g蜂蜜之间,其中荞麦蜜的总酚酸含量远高于其它种类的蜂蜜。应用黄嘌呤-黄嘌呤氧化酶体系产生的超氧阴离子自由体系和FeSO4诱导的脂质过氧化模型,研究了稀释蜂蜜的抗氧化活性,结果表明,十种蜂蜜均有抑制超氧阴离子自由基和抗脂质过氧化的作用,呈现量效关系。其中荞麦蜜的抗氧化活性最强。本研究还观察到,蜂蜜中总酚酸的含量与其抗氧化活性成正相关,表明蜂蜜的抗氧化活性可能与其所含的总酚酸有关。十种中国蜂蜜中含有酚酸类抗氧化剂可能是其发挥保健功能的有效成分之一。     

Effects of mashing on total phenolic contents and antioxidant activities of malts and worts

Effects of mashing on total phenolic contents (TPC), radical‐scavenging activity, reducing power and metal chelating activity of malts and corresponding worts were clarified in this study. Results showed that there were significant variations in TPC and antioxidant activity across malts and worts. An 8.8% of increase in TPC was observed during the early stage of mashing, accompanied by an increase in antioxidant activity. However, 2.6% of decrease in TPC and inconsistent changes in antioxidant activity were found during the mashing at higher temperature. Overall, mashing resulted in 6.0% and >10.0% of increases in TPC and antioxidant activity, respectively. Moreover, Pearson correlation analysis revealed that there were good correlations (ranging from 0.622 to 0.735, P < 0.01) between TPC and antioxidant activity of malts and worts. Additionally, mashing resulted in more positive correlations between TPC and antioxidant activity, emphasising the key role of malt phenolic compounds for wort antioxidant activity.     

HPLC flavonoid profiles as markers for the botanical origin of European unifloral honeys

The HPLC phenolic profiles of 52 selected unifloral honey samples produced in Europe were analysed to detect possible markers for the floral origin of the different honeys. Lime‐tree (five markers), chestnut (five markers), rapeseed (one marker), eucalyptus (six markers) and heather (three markers) honeys had specific markers with characteristic UV spectra. In addition, the flavanone hesperetin was confirmed as a marker for citrus honey, as well as kaempferol for rosemary honey and quercetin for sunflower honey. Abscisic acid, which had been reported to be a possible marker for heather honey, was also detected in rapeseed, lime‐tree and acacia honeys. Ellagic acid in heather honey and the hydroxycinnamates caffeic, p‐coumaric and ferulic acids in chestnut, sunflower, lavender and acacia honeys were also detected. The characteristic propolis‐derived flavonoids pinocembrin, pinobanksin and chrysin were present in most samples in variable amounts. © 2001 Society of Chemical Industry     

Effect of microwave treatment on phenolic content and antioxidant activity of citrus mandarin pomace

The effects of microwave treatment on the phenolic compounds and antioxidant capacity of citrus mandarin pomace were evaluated. After treatment, methanol extracts of citrus pomace were prepared and the contents of phenolic acids (free and bound) and flavanol, flavanone and flavonol compounds (FCs) were determined by HPLC. Antioxidant capacity of pomace extracts was measured using DPPH radical-scavenging assay, hydroxyl radical-scavenging assay and reducing power. After microwave treatment, the free fraction of phenolic acids increased, whereas the bound fractions decreased and antioxidant activity was increased. The content of total FCs increased with power but, at longer irradiation time, it declined which meant that some FCs might be degraded. The results indicated that appropriate microwave treatment could be an efficient process to liberate and activate the bound phenolic compounds and to enhance the antioxidant activity of citrus mandarin pomace.     

Antioxidant activity,color chromaticity coordinates,and chemical characterization of monofloral honeys from Morocco

The bioprospecting of several monofloral Moroccan honeys was carried out. The antiradical activity expressed as mmol Trolox equivalents/kg of honey and evaluated by 2,2-diphenyl-1-picrylhydrazyl assay, ranged from 0.15 for euphorb honey to 1.08 for citrus honey. The antioxidant activity expressed as mmol Fe²⁺/kg and evaluated by ferric ion reducing antioxidant power assay, ranged from 0.96 for euphorb honey to 4.74 for orange honey. The total phenol content was evaluated by colorimetric assay, while the color attributes were evaluated as transmittance data. Significant Pearson correlation factors were found between total polyphenol amount and antioxidant activity and between color attributes and antioxidant activity. Furthermore the chemical composition of volatile organic compounds was determined. The volatile organic compounds chemical composition of the studied honeys was mainly represented by terpene and benzene derivatives, Maillard reaction products, isoprenoids, and hydrocarbons. The volatiles fingerprint, as well as a targeted high-performance liquid chromatography analysis of the polar components, was used to tentatively confirm the declared botanical origin of the samples studied.     

Evaluation of the phenolic content,antioxidant activity and colour of Slovenian honey

Honey samples from the seven most common honey types in Slovenia were screened for total phenolic content by the modified Folin–Ciocalteu method, for potential antioxidant activity using the ferric reducing antioxidant power (FRAP) assay and by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method for antiradical activity. In addition the colour characteristics of honey samples were analysed. The results of the study showed that total phenolic content, antioxidant activity and colour parameters differ widely among different honey types. Phenolic content expressed as gallic acid equivalent ranged from 44.8 mg/kg in acacia honey to 241.4 mg/kg in fir honey. Antioxidant activity was the lowest in the brightest acacia and lime honeys and the highest in darker honeys, namely fir, spruce and forest. The colour of the Slovenian honeys, analysed in this study was very variable and ranged from pale yellow to dark brown. Correlations between the parameters analysed were found to be statistically significant (p < 0.05).     

Antioxidant activity of yogurt made from milk characterized by different casein haplotypes and fortified with chestnut and sulla honeys

The aim of this work was to evaluate the antioxidant activity of yogurt made from milk characterized by different casein (CN) haplotypes (α_s1-, β-, κ-CN) and fortified with chestnut and sulla honeys. The CN haplotype was determined by isoelectric focusing, whereas antioxidant activity of yogurt was measured using 2,2’-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid and ferric-reducing antioxidant power. The statistical analysis showed a significant effect of the studied factors. The results showed that chestnut honey presented the highest phenolic acid and flavonoid contents, which are closely associated with its high antioxidant activity. The antioxidant activity of fortified yogurt samples was affected both by different CN haplotypes and by type of honey added. Yogurts fortified with chestnut honey showed higher antioxidant activity than those fortified with sulla honey. The different behavior observed among the fortified yogurts led us to hypothesize that the effects of protein-polyphenol complex on antioxidant activity are interactive. The results suggest that milk proteins polymorphism and polyphenols play different roles in affecting the bioavailability and the antioxidant activity of yogurt.     

The effect of feed moisture and temperature on tannin content,antioxidant and antimicrobial activities of extruded chestnuts

This study focuses on the effect of extrusion processing on tannin reduction, phenolic content, flavonoid content, antioxidant and anitimicrobial activity. Extrusion temperature (120 and 140 °C) and feed moisture (25% and 28%) were used on the tannin content, antioxidant and antimicrobial activities. Extrusion cooking reduced tannin content up to 78%, and improved antioxidant activity from 12.89% to 21.17% in a concentration dependant manner without affecting its antimicrobial activity that varied from 250 to 500 mg. The time–kill assay confirmed the ability of extruded chestnut to reduce Pseudomonas aeruginosa count below detectable limit that reduced the original inoculum by 3log10 CFU/mL. Overall, the results showed that extrusion cooking might serve as a tool for tannin reduction and could improve the antioxidant and antimicrobial properties of chestnut, which might be helpful for chestnut related products in the food industry.     

PREDICTION OF HONEY SHELF LIFE

Fourteen commercial honey samples of different botanical origin (acacia, chestnut, citrus, eucalyptus, multifloral) were stored for up to 18 months at room temperature. Both 5-hydroxymethylfurfural (HMF) and diastase were evaluated and kinetics carried out. The highest HMF increase was in citrus and eucalyptus honeys at 3 mg/kg/month; the lowest in chestnut at 0.256 mg/kg/month. The highest diastase deactivation was in eucalyptus honey at 0.485 DU/kg/month; the lowest was in chestnut at 0.258 DU/kg/month. Honey shelf life was estimated for both indices, HMF and diastase, using a Bayesian approach. The results show that commercial honey shelf life depends on botanical origin as well as processing. Except chestnut, all other honeys showed shorter shelf lives than the declared one (usually 36 months). The shortest values, 15 months, were for citrus and eucalyptus honeys. The longest, 20 months, was for acacia and multifloral honeys.

PRACTICAL APPLICATIONS

Both kinetic equations and results of simulations can be used to estimate, for quality control purposes as well as regulation requirements, the most probable value of shelf life for a specific honey.     

ANTIOXIDANT ACTIVITY AND PHENOLIC ACID CONSTITUENTS OF CHESTNUT (CASTANIA SATIVA MILL.) HONEY AND PROPOLIS

This study describes the constituents of phenolic acids and antioxidant activities of chestnut ( Castania sativa Mill.) honeys and propolis in Turkey. Antioxidant activity of the chestnut honeys and propolis were examined by three different methods, namely scavenging of free radical 2, 2-diphenyl-1-picrylhydrazyl, FRAP, and cupric reducing antioxidant power. Total phenolic contents were determined by using Folin–Ciocalteu reagent as GA equivalent. The phenolic constituents were also determined by HPLC. The antioxidant activities were compared with standard antioxidants such as catechin, BHT and Trolox. The antioxidant activities of all the samples were found high and related to the sample concentrations. The ethanolic propolis extracts showed the highest antioxidant activity. The major phenolic acids of the chestnut honeys and propolis identified by HPLC with PDA detection were coumaric acid, FA, cinnamic acid, CA and ChA.

PRACTICAL APPLICATIONS

In this study, some phenolic acid components and antioxidant capacity of chestnut ( Castania sativa Mill.) honey and propolis were measured. The comparative findings from antioxidant activities and phenolic acid analyses of honey and propolis samples of chestnut origin provide important criteria for considering their nutritional and nutraceutical potentials. Comparison of our results with literature data also ranks the chestnut honey and propolis as better sources of antioxidants among those from other floral origins.     

Biological activities and chemical composition of three honeys of different types from Anatolia

In this study, we investigated and compared some chemical properties and in vitro biological activities of three different types of Turkish honey. The first two honey samples were monofloral from chestnut and rhododendron flowers, collected from the east Black Sea region, and the third sample was the heterofloral form of astragalus (Astragalus microcephalus Willd.), thyme (Thymus vulgaris) and other several mountain flowers, collected from Erzincan in Eastern Anatolia. The chemical properties of the honey samples, such as total moisture, ash, total protein, sucrose, invert sugar, diastase activity, hydroxymethylfurfural content and acidity, were determined. Total phenolics, superoxide radical- and peroxynitrite-scavenging activities, and ferric reducing/antioxidant power measurements were used as antioxidant capacity determinants with ±-catechin, butylated hydroxytoluene, ascorbic acid, and trolox^® used as reference. The antimicrobial activity was studied by the agar diffusion method, using eight bacteria and two yeasts. The mineral contents were also determined by an AAS method. The chestnut flower honey had the highest phenolic content, superoxide radical-scavenging activity and reducing power, while the heterofloral honey sample exhibited the highest peroxynitrite-scavenging activity. The antioxidant activities were also found to be related to the sample concentrations. The mineral content of the chestnut honey was much higher than the others. The samples showed moderate antimicrobial activity against some microorganisms, especially Helicobacter pylori ATCC 49503, Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633, Candida tropicalis ATCC 13803 and Candida albicans ATCC 10231. The honey samples studied proved to be a good source of antioxidants and antimicrobial agents that might serve to protect health and fight against several diseases.     

Antioxidant Activity of Artisanal Honey From Tabasco,Mexico

Potential claims for honey, floral variety and their health properties are relevant for small farmers and artisan producers. The antioxidant activity of honey samples from cacao farms, mangrove, citrus, and coconut groves from Mexico was established by applying a multiple-method approach, which included determination of the level of total phenolic compounds and total flavonoids. Total phenolics and total flavonoids ranged from 51 to 134 mg gallic acid equivalents (GAE)/100 g honey and from 29.6 to 187.1 mg rutin equivalents/100 g honey respectively. Methanolic and aqueous solutions had similar profiles for inhibition of 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical (range from 33 to 85%) but the aqueous solutions tended to show lower radical scavenging properties. Linear correlations were established between flavonoids contents and percentage inhibition of DPPH, but phenolics contents were not well correlated (R² = 0.68) to the ferric reducing antioxidant power (FRAP) values which showed wide ranges from 48 to 152 mg Trolox/100 g honey. No patterns could be found in relation to antioxidant activities and the agrifood system of origin, floral availability, collection location, or season. Artisan honey samples from Tabasco were highly variable in their antioxidant properties, possibly because of the biodiversity and seasonal variations, which contribute to their unique nature. The antioxidant tests used in this study could be useful to verify the antioxidant function of honey.     

不同豇豆中酚类含量与抗氧化活性

为深入了解豇豆的营养价值,以11个不同品种的豇豆样品为原料,对其总酚含量、总黄酮含量及抗氧化活性(总还原能力、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力、·OH清除能力)进行分析,并讨论酚类物质含量及抗氧化活性的相关性。结果表明,不同品种的豇豆酚类物质含量和抗氧化活性差异显著。在测定的样品中,新杂1号表现出最高的总酚含量(5.59 mg GAE/g)、总黄酮含量(4.12 mg CAE/g)及抗氧化活性(总还原能力和DPPH自由基清除能力);豇豆中总酚含量、总黄酮含量与总还原能力、DPPH自由基清除能力之间有极显著相关性(P0.01),与·OH清除能力之间没有显著相关性。     

4种典型谷物中酚类化合物的抗氧化和抗癌细胞增殖活性

将荞麦、大麦、小麦、水稻4种全谷物用70%(v/v)乙醇水浸提后,经AB-8大孔吸附树脂富集/分离,分别得到4种全谷物酚类提取物,测定其总酚和总黄酮含量,并运用高效液相质谱联用(HPLC-MS)法鉴定酚类化合物组成。在此基础上,通过体外法测定4种谷物的抗氧化能力和抗Caco-2细胞增殖能力,并探讨多酚含量与活性之间的相关性。结果表明:4种谷物酚类提取物中总酚和总黄酮含量从高到低的顺序均依次为:荞麦>大麦>水稻>小麦。从4种全谷物中成功确定了21种酚类化合物。4种谷物酚类化合物均具有一定的抗氧化能力和抗Caco-2细胞增殖能力,其强弱顺序均为:荞麦>大麦>水稻>小麦,而且其总酚含量与抗氧化和抗Caco-2细胞增殖活性之间以及抗氧化活性与抗Caco-2细胞增殖活性之间均具有良好的相关性。