Distribution of bound and free phenolic acids in oranges (Citrus sinensis) and Grapefruits (Citrus paradisi)

Free phenolic acids may be the precursors for vinyl phenols and off-flavours formed in citrus products during storage. Quantitative determination of free and bound phenolic acids in fruit parts of grapefruit (Citrus paradisi Macfadyen) and oranges (Citrus sinensis (L) Osbeck) was performed by extraction with ethyl acetate, silica gel column chromatography and HPLC analyses of samples before and after alkaline hydrolysis. The content of free and bound phenolic acids was further determined in juice derived from fruit harvested early, mid and late in season. As found previously for ferulic acid, phenolic acids occur mainly in bound forms in grapefruits and oranges. In both fruits the peels contained the major portion of cinnamic acids compared with the endocarp, and the flavedo was richer in hydroxycinnamic acids than the albedo. In most cases, hydroxycinnamic acid content was in the following order: ferulic acid>sinapic acid>coumaric acid>caffeic acid. Results showed that the content of bound cinnamic acids was unchanged or slightly elevated from early to late season. However, the content of free acids was reduced during that period.     

Phenolic compounds,lycopene and antioxidant activity in commercial varieties of tomato (Lycopersicum esculentum)

Nine commercial varieties of tomato (Rambo, Senior, Ramillete, Liso, Pera, Canario, Durina, Daniella and Remate) produced in Spain were analysed for their lycopene content, content of phenolic compounds and antioxidant capacity. The phenolic compounds were characterised as flavonoids (quercetin, kaempferol and naringenin) and hydroxycinnamic acids (caffeic, chlorogenic, ferulic and p‐coumaric acids). Antioxidant activity was measured using the DPPH and ABTS assays. The concentrations of lycopene and the various phenolic compounds as well as the antioxidant activity were significantly influenced by the tomato variety. Quercetin, the most abundant flavonoid, was found in concentrations ranging between 7.19 and 43.59 mg kg^?1 fresh weight, while naringenin levels were lower than 12.55 mg kg^?1. The most abundant hydroxycinnamic acid was chlorogenic acid, with values ranging from 14 to 32 mg kg^?1 fresh weight, followed by caffeic acid, while p‐coumaric and ferulic acids showed similar concentrations lower than 5 mg kg^?1. The highest content of lycopene was found in Ramillete, Pera and Durina (>50 mg kg^?1 fresh weight), while the concentration in the other varieties was between 50 and 30 mg kg^?1, with the exception of Liso (less than 20 mg kg^?1). The antioxidant activity of tomato extracts varied with the tomato variety and the assay method used. Individual compounds found to be significantly related to antioxidant capacity were lycopene and ferulic and caffeic acids, but not quercetin and chlorogenic acid. © 2002 Society of Chemical Industry     

Fenton oxidation products derived from hydroxycinnamic acids increases phenolic‐based compounds and organic acid formation in sugar processing

The hydroxycinnamic acids (HCAs), caffeic acid (CaA), p‐coumaric acid (pCoA) and ferulic acid (FeA) are the main phenolic acid colour precursors present in sugar cane juice. The Fenton oxidative degradation products of these HCAs and mixture using Fe²⁺/H₂O₂ at pH 4.72 at 25 °C were identified using chromatography and mass spectrometry techniques. Oxalic (≤14 wt%), isobutyric (≤13.5 wt%) and formic acids (≤1.3 wt%) were the main organic acids formed. CaA produced the highest proportion of oxalic and isobutyric acids, while FeA produced the highest proportion of formic acid. The presence of increased proportion of oxalic acid in juice will increase the proportion of calcium oxalate scale in sugar mill heat exchangers. The phenolic‐based products identified include protocatechuic aldehyde and 4‐hydroxybenzoic acid and the basic phenols, p‐allyphenol, p‐vinylguaiacol, trans‐isoeugenol, which when present in juice may react with juice constituents to increase juice colour in subsequent processing.     

p‐Coumaric acid in cereals: presence,antioxidant and antimicrobial effects

Coumaric acid is a hydroxy derivative of cinnamic acid and naturally occurs in three isomers (ortho‐, meta‐ and para‐); p‐coumaric acid is one of the most commonly occurring isomer in nature. p‐coumaric acid, classified as a phytochemical and nutraceutical, is found in various edible plants, such as carrots, tomatoes and cereals. p‐coumaric acid (4‐hydroxy‐cinnamic acid) occurs widely in the cell walls of graminaceous plants. It decreases low‐density lipoprotein (LDL) peroxidation, shows antioxidant and antimicrobial activities and plays an important role in human health. It is found in the endosperm of kernels at a limited level; however, the amount of p‐coumaric acid increases significantly in peripheral tissues. In terms of cereal types, it appears that pericarp fractions in barley, wheat, oat and corn are the fractions richest in p‐coumaric acid. It is both a good antioxidant and a good antimicrobial; therefore, it is natural alternative instead of synthetic additives, nowadays.     

Phenolic acid concentrations in organically and conventionally cultivated spring and winter wheat

BACKGROUND: Organic crops are often thought to contain more phenolic secondary metabolites than conventional ones. This study evaluated the influence of organic and conventional farming on concentrations of phenolic acids in spring and winter wheat cultivars. RESULTS: Five phenolic acids were identified: ferulic, sinapic, p‐coumaric, vanillic and p‐hydroxybenzoic acid. Ferulic acid was the main phenolic acid in the grain of all tested wheat varieties. Significant differences among the examined cultivars in concentration of particular compounds were observed. Concentrations of phenolic acids varied significantly in organic and conventional wheat. Levels of ferulic and p‐coumaric acids, as well as the total phenolic acid content were higher in organic crops. Concentrations of sinapic acid in spring wheat, as well as vanillic and p‐hydroxybenzoic acid levels in both types of wheat were significantly higher in conventional grains. The 1000 kernel weight (TKW) of spring and winter wheat was significantly lower in organic crops. CONCLUSION: Organically produced spring and winter wheat had significantly higher concentrations of ferulic and p‐coumaric acid as well as the total phenolic acid content than conventional wheat, though the differences in the levels of phenolics were not large. However, these differences are probably caused mainly by smaller size of organic wheat kernels (lower TKW). Copyright © 2011 Society of Chemical Industry     

p‐Coumaric acid and its conjugates: dietary sources,pharmacokinetic properties and biological activities

p‐Coumaric acid (4‐hydroxycinnamic acid) is a phenolic acid that has low toxicity in mice (LD₅₀ = 2850 mg kg^?1 body weight), serves as a precursor of other phenolic compounds, and exists either in free or conjugated form in plants. Conjugates of p‐coumaric acid have been extensively studied in recent years due to their bioactivities. In this review, the occurrence, bioavailability and bioaccessibility of p‐coumaric acid and its conjugates with mono‐, oligo‐ and polysaccharides, alkyl alcohols, organic acids, amine and lignin are discussed. Their biological activities, including antioxidant, anti‐cancer, antimicrobial, antivirus, anti‐inflammatory, antiplatelet aggregation, anxiolytic, antipyretic, analgesic, and anti‐arthritis activities, and their mitigatory effects against diabetes, obesity, hyperlipaemia and gout are compared. Cumulative evidence from multiple studies indicates that conjugation of p‐coumaric acid greatly strengthens its biological activities; however, the high biological activity but low absorption of its conjugates remains a puzzle. © 2015 Society of Chemical Industry     

Comparative content of some phytochemicals in Spanish apples,peaches and pears

Dietary fibre, total polyphenols and phenolic acids in Spanish apples, peaches and pears were analysed and compared with their total radical‐trapping antioxidative potential (TRAP). There were no significant differences in the content of dietary fibre among the studied fruits. The content of total polyphenols was 2.4 ± 0.4, 2.1 ± 0.3 and 6.9 ± 0.7 g kg^?1 in peeled fruits and 4.7 ± 0.4, 4.5 ± 0.4 and 11.1 ± 1.2 g kg^?1 in their peels for peaches, pears and apples respectively. The contents of dietary fibre, total polyphenols, caffeic, p‐coumaric and ferulic acids and the TRAP values were significantly (P < 0.05) higher in peels than in peeled fruits. The contents of all studied compounds and the TRAP values were significantly higher in peeled apples and their peel than in peaches and pears. We observed a strong correlation between the contents of total polyphenols and phenolic acids and the total radical‐trapping antioxidative potential in all three fruits. The relatively high content of dietary fibre, the highest contents of total polyphenols, caffeic, p‐coumaric and ferulic acids and the highest value of TRAP make apples preferable among the studied fruits for dietary prevention of atherosclerosis and other diseases. © 2002 Society of Chemical Industry     

Identification of ferulate oligomers from corn stover

BACKGROUND: Cross‐links between plant cell wall polymers negatively impact forage digestibility. Hydroxycinnamates and their oligomers act as cross‐links between polysaccharides and/or polysaccharides and lignin. Higher ferulate oligomers such as dehydrotrimers were identified in cereal grains but not in vegetative organs of grasses. The aim of this study was to characterize ester‐linked hydroxycinnamate oligomers from corn stover with special emphasis on ferulate dehydrotrimers. RESULTS: With the exception of the 4‐O‐5‐dehydrodiferulic acid all known ferulate dehydrodimers, including the recently described 8‐8(tetrahydrofuran) dimer, were identified in the alkaline hydrolyzate of corn stover after chromatographic fractionation. Next to dehydrodimers, 18 cyclobutane dimers made up of ferulic acid and/or p‐coumaric acid were identified by GC‐MS of the dimeric size exclusion chromatography fraction. Ferulate dehydrotrimers were isolated by using multiple chromatographic procedures and identified by UV spectroscopy, MS and NMR. Four trimers were unambiguously identified as 5‐5/8‐O‐4‐, 8‐O‐4/8‐O‐4‐, 8‐8(aryltetralin)/8‐O‐4‐, and 8‐O‐4/8‐5‐dehydrotriferulic acids, a fifth tentatively as 8‐5/5‐5‐dehydrotriferulic acid. CONCLUSION: The formation of ferulate dehydrotrimers is not limited to reproductive organs of grasses but also contribute to network formation in the cell walls of vegetative organs. Although radically coupled hydroxycinnamate dimers and oligomers were in the focus of researchers over the last decade, the earlier described cyclobutane dimers significantly contribute to cell wall cross‐linking. Copyright © 2010 Society of Chemical Industry     

Phenolic compounds in peanut seeds: Enhanced elicitation by chitosan and effects on growth and aflatoxin B1 production by Aspergillus flavus

Effects of chitosan and Aspergillus flavus to enhance elicitation of phenolic compounds in viable peanut seeds were conducted at two water activity levels. In vitro effects of phenolic acids on A. flavus growth and aflatoxin B₁ production were also studied. Chitosan enhanced elicitation of free phenolic compounds (FPC) at Aw .85 and .95 levels. A. flavus initially decreased and subsequently increased FPC content, but bound phenolic compounds (BPC) decreased during incubation. Chitosan + A. flavus treatment caused an increase in FPC reaching a plateau between 24–48 h at Aw .85 while BPC levels increased over the same period at both Aw levels. Major free and bound phenolic acids detected were p‐coumaric, ferulic and an unknown phenolic acid eluting at a retention time of 22 min. Generally, chitosan significantly enhanced elicitation of free ferulic and p‐coumaric acids and bound p‐coumaric acid at Aw .95. Free unknown phenolic and bound ferulic acids at Aw .85 were enhanced by chitosan. A. flavus caused significant induction of bound p‐coumaric and ferulic acids and free unknown phenol at Aw .85. Chitosan + A. flavus enhanced free p‐coumaric (3 h) and unknown phenolic acids and bound p‐coumaric acid at Aw .95 while bound ferulic acid was enhanced at Aw .85. Chitosan limited A. flavus growth and subsequent aflatoxin production by inducing susceptible tissues to produce more preformed phenolic compounds.

Analysis of liquid cultures of A. flavus revealed that p‐coumaric, ferulic, and vanillic acids and a mixture of these phenolic acids slightly inhibited mycelial growth. Production of aflatoxin B₁ by A. flavus was completely inhibited at 1 mM and 10 mM concentrations of the phenolic acids and their mixture on four days of incubation. Mode of action of phenolic acids is likely on the secondary pathway for aflatoxin B₁ production and not on the primary metabolism for fungal growth.     

Phenolic acids from malt are efficient acetylcholinesterase and butyrylcholinesterase inhibitors

Anticholinesterase activities of mashes produced using wheat (‘Wheat Pale’) or barley malts (‘Pilsner’, ‘Pale Ale’, ‘Munich Light’, ‘Carahell’ or ‘Carared’) were studied by spectrophotometric method. The highest inhibition of acetylcholinesterase and butyrylcholinesterase was observed at 52 °C and/or 64 °C, followed by a decrease or stabilization of the activity at 72 °C. Changes in the total phenolics content in the test mashes were correlated with changes in the acetylcholinesterase and/or butyrylcholinesterase activities. Phenolic acids were singled out from phenolic compounds for more detailed studies owing to their simplicity and structural similarity to well‐known cholinesterase inhibitors. The main phenolic acids in the test malts were ferulic, gallic, p‐coumaric and vanillic acids followed by chlorogenic, caffeic, syringic, p‐OH‐benzoic, sinapic and protocatechuic acids. The anticholinesterase activities of the phenolic acids were studied using model standard solutions at concentrations similar to the maximal content of these compounds in the test mashes. Among the phenolic acids, p‐coumaric acid had the largest share in the anticholinesterase activity, even though it was present in the test mashes at a significantly lower concentration (~0.38 mm L^?1) than ferulic acid (~1.00 mm L^?1). Sinapic acid and p‐OH‐benzoic acid (0.03 and 0.01 mm L^?1, respectively) were equally efficient inhibitors as ferulic acid at ~1.00 mm L^?1. This preliminary study should be extended to other phenolic compounds from malt (wort) in the near future. Copyright © 2012 The Institute of Brewing & Distilling     

Flavour compounds of Greek cotton honey

Finding marker compounds is a powerful tool in the determination of the botanical origin of honey. For this purpose the flavour fraction of Greek cotton honey was investigated. A striking characteristic of this type of honey is the presence of more than 35 phenolic compounds in the extract, accounting for almost 60% of the total amount of compounds positively identified by gas chromatography/mass spectrometry. In comparison with honeys of nine different origins, a total of 15 compounds could serve as potent markers for cotton honey, namely cinnamaldehyde (0.44%), cinnamyl alcohol (1.79%), cinnamic acid (1.13%), neryl and geranyl nitrile (0.16 and 0.41% respectively), benzenepropanol (0.5%), homovanillyl alcohol (0.6%), (E)‐ and (Z)‐p‐methoxy‐cinnamic acid (0.48 and 0.14% respectively), 2‐methyl‐p‐phthalaldehyde (0.22%), coniferaldehyde (0.47%), p‐coumaric acid (1.77%), ferulic acid (0.51%), scopoletin and scoparone (0.47%). Copyright © 2005 Society of Chemical Industry     

Genomic Study of the Absorption Mechanism of p‐Coumaric Acid and Caffeic Acid of Extract of Ananas Comosus L. Leaves

Cardiac disease has emerged as the leading cause of death worldwide, and food rich in phenolic acids has drawn much attention as sources of active substances of hypolipidemic drug. Ananas comosus L. (pineapple) is one of the most popular tropical and subtropical fruits. Isolated from pineapple leaves, EAL(Extract of Ananas Comosus L. Leaves) is rich in phenolic acids, such as p‐coumaric acid, caffeic acid, and other phenolics, highly relevant to the putative cardiovascular‐protective effects, which suggests its potential to be a new plant medicine for treatment of cardiac disease, but little is known about absorption, distribution, metabolism, and excretion of EAL in animals or human beings. In this study, we employed cDNA microarray, Caco‐2 cell lines, and rat intestinal model to explore the absorption behavior of p‐coumaric acid and caffeic acid in EAL. The permeation of 2 substances was concentration and time dependent. Results also indicated that monocarboxylic acid transporter was involved in the transepithelial transport of p‐coumaric acid and caffeic acid.     

Color enhancing effect of carboxylic acids on anthocyanins

The color enhancing effect of aromatic and aliphatic carboxylic acids on anthocyanin-glucosides was investigated in this work. The color of black rice anthocyanin-rich fraction was successfully improved after the addition of aromatic acids (p-coumaric acid, ferulic acid, and sinapic acid), aliphatic acid (lipoic acid) and tannic acid (as a complex acid). The addition of carboxylic acids showed an enhancing and stabilizing effect on the color of black rice juice during storage, which was observed through changes in CIELAB and spectrophotometric parameters. Sinapic, ferulic, and p-coumaric acids enhanced the color of black rice juice the most, with the highest efficiency for the dimethoxylated cinnamic acid derivate (sinapic acid). New anthocyanin-derived pigments were first isolated through silica gel TLC and identified using Maldi-Mass spectrometry at m/z values of 613, 659, 673, and 639, respectively, for vinylpyranoanthocyanins formed after adding coumaric, ferulic, sinapic, and lipoic acids. Based on these experimental results, the addition of carboxylic acids in an anthocyanin-rich fraction can be used as an efficient tool for their color enhancement and stability.     

Ferulic Acid Production in the Brewing of Rice Wine (Sake)

The traditional Japanese alcoholic beverage sake is produced by fermentation of rice by Saccharomyces cerevisiae and Aspergillus oryzae. A. oryzae releases ferulic acid, an antioxidant, from steamed rice during the fermentation process. The concentration of ferulic acid increased with time during fermentation and the production rate peaked 9–12 days post inoculation. Analysis of the fermentation cultures of Aspergillus oryzae, by high‐performance liquid chromatography (HPLC), revealed that p‐coumaric acid induced an 18.9‐fold increase in the level of ferulic acid. Furthermore, SDS‐PAGE analysis revealed an increase or decrease in the level of specific proteins after the addition of p‐coumaric acid to fermentation cultures of Aspergillus oryzae. Ferulate esterase (FAE) activity was observed in the fermented sake ten days following the start of the fermentation process. These results suggest that the level of ferulic acid is regulated by the enzymes synthesized by A. oryzae during the sake brewing process.     

Variation of the chemical composition of tomato cultivars (Lycopersicon esculentum Mill.) according to resistance against the tomato yellow leaf curl virus (TYLCV)

BACKGROUND: Tomato producers are looking for alternatives to protect their crops against the tomato yellow leaf curl virus (TYLCV), including replacement of cultivars with other more resistant ones. Major chemical components, sugars, mineral composition, organic acids, lycopene, total phenols and hydroxycinnamic acids were determined in six tomato cultivars, three of them (Boludo, Dorothy and Tyna) resistant, and the other three (Daniela, Dominique and Thomas), non‐resistant against TYLCV. RESULTS: The Daniela cultivar showed the greatest difference with respect to the others, mostly due to the higher content of soluble solids. The major significant differences between the mean values according to the cultivar and resistance against the TYLCV were observed for total soluble solids, pH, ascorbic acid, total phenols and hydroxycinnamic acids. High coefficients of correlation were found between glucose and fructose, and among ferulic, caffeic and p‐coumaric acids. CONCLUSION: Linear discriminant analysis made it possible to differentiate tomato samples according to the cultivar. A clear varietal influence on the chemical composition was observed; however, resistance or non‐resistance against TYLCV does not seem to influence the chemical composition. Copyright © 2008 Society of Chemical Industry     

Color of whole-wheat foods prepared from a bright-white hard winter wheat and the phenolic acids in its coarse bran

Abstract: The color of wheat kernels often impacts the color and thereby the value of wheat‐based foods. A line of hard white winter wheat (B‐W HW) with bright appearing kernels has been developed at the Kansas State Agricultural Research Center. The objective of this study was to compare the color of several foods made from the B‐W HW wheat with those of 2 hard white wheat cultivars, Trego and Lakin. The B‐W HW kernels showed higher lightness (L*, 57.6) than Trego (55.5) and Lakin (56.8), and the increased lightness was carried over to its bran and whole‐wheat flour. Alkaline noodle and bread crumb made from the B‐W HW whole‐wheat flour showed slightly higher lightness (L*) than those made from Trego and Lakin. The sum of soluble and bound phenolics extracted from the 3 wheat brans, which had not been preextracted to remove lipids, was found to be 17.22 to 18.98 mg/g. The soluble phenolic acids in the brans were principally vanillic, ferulic, and syringic. The bound phenolic acids in the brans were dominated by ferulic, which accounted for 50.1% to 82.2% of total identified bound phenolic acids. Other bound phenolic acids were protocatechuic, caffeic, syringic, trans‐cinnamic, p‐hydroxybenzoic, p‐coumaric, and vanillic. The lightness (L*) values of coarse wheat brans correlated positively with their levels of bound protocatechuic (r = 0.72, P < 0.01) and p‐hydroxybenzoic acids (r = 0.75, P < 0.01).     

Efficient synthesis of hydroxystyrenes via biocatalytic decarboxylation/deacetylation of substituted cinnamic acids by newly isolated Pantoea agglomerans strains

BACKGROUND: Decarboxylation of substituted cinnamic acids is a predominantly followed pathway for obtaining hydroxystyrenes—one of the most extensively explored bioactive compounds in the food and flavor industry (e.g. FEMA GRAS approved 4‐vinylguaiacol). For this, mild and green strategies providing good yields with high product selectivity are needed. RESULTS: Two newly isolated bacterial strains, i.e. Pantoea agglomerans KJLPB4 and P. agglomerans KJPB2, are reported for mild and effective decarboxylation of substituted cinnamic acids into corresponding hydroxystyrenes. Key operational parameters for the process, such as incubation temperature, incubation time, substrate concentration and effect of co‐solvent, were optimized using ferulic acid as a model substrate. With strain KJLPB4, 1.51 g L^?1 4‐vinyl guaiacol (98% yield) was selectively obtained from 2 g L^?1 ferulic acid at 28 °C after 48 h incubation. However, KJPB2 provided vanillic acid in 85% yield after 72 h following the oxidative decarboxylation pathway. In addition, KJLPB4 was effectively exploited for the deacetylation of acetylated α‐phenylcinnamic acids, providing corresponding compounds in 65–95% yields. CONCLUSION: Two newly isolated microbial strains are reported for the mild and selective decarboxylation of substituted cinnamic acids into hydroxystyrenes. Preparative‐scale synthesis of vinyl guaiacol and utilization of renewable feedstock (ferulic acid extracted from maize bran) have been demonstrated to enhance the practical utility of the process. Copyright © 2011 Society of Chemical Industry     

Composition and Nutrient Value Proposition of Brewers Spent Grain

Brewer's spent grain (BSG), a major brewing industry byproduct, is generated in large quantities annually. This review summarizes research into the composition and preservation of BSG, different extraction techniques for BSG proteins and phenolic acids, and the bioactivities of these phenolic components. Moreover, this article also highlights BSG integration into foodstuff for human consumption and animal feed supplements. BSG is considered a rich source of fiber, protein, and phenolic compounds. The phenolic acids present in BSG are hydroxycinnamic acids (ferulic, p‐coumaric, and caffeic acids), which have many biofunctions, such as antioxidant, anticarcinogenic, antiatherogenic, and antiinflammatory activities. Previously, attempts have been made to integrate BSG into human food, such as ready‐to‐eat snacks, cookies and bread, to increase fiber and protein contents. The addition of BSG to animal feed leads to increased milk yields, higher fat contents in milk, and is a good source of essential amino acids. Therefore, many studies have concluded that integrating the biofunctional compounds in BSG into human food and animal feed has various health benefits.     

Digestibility of silages in relation to their hydroxycinnamic acid content and lignin composition

BACKGROUND: The effectiveness of the analysis of cell wall‐bound hydroxycinnamic acids and the composition of lignin to evaluate the in vivo digestibility of a silage collection with unknown botanical composition was evaluated. RESULTS: Syringyl units content and total etherified phenols showed the highest correlation coefficients with in vivo dry matter digestibility (IVDMD) (r = ? 0.792 and r = ? 0.703, respectively), while guaiacyl units and total phenols showed the highest correlation coefficients with in vivo organic matter digestibility (IVOMD) (r = ? 0.871 and r = ? 0.817, respectively). Using the above‐mentioned chemical parameters, 10 equations were also developed to predict in vivo digestibility. The prediction of IVDMD produced a high adjusted R² value (0.710) using syringyl, total lignin, etherified total phenols, esterified ferulic acid and total phenol content as predictors. The prediction of IVOMD produced a higher adjusted R² value (0.821) using guaiacyl, total phenols, total ferulic acid and etherified p‐coumaric acid content as predictors. CONCLUSION: Cell wall digestibility depends on a multiplicity of factors and it is not possible to attribute a causal effect on in vivo digestibility to any single factor. However, syringyl and guaiacyl content and etherified phenols emerge as good predictors of digestibility. Copyright © 2010 Society of Chemical Industry     

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.