Oil content,phenolic profiling and antioxidant potential of Tunisian olive drupes

BACKGROUND: The aim of this work was to investigate the effect of the maturation process of the olive fruit on oil content, phenolic profile and antioxidant activity of four Tunisian cultivars (Zelmati, Chemchali, Chemlali and Chétoui). RESULTS: The average oil content of the studied varieties ranged between 17.50% and 20.25% at the first stage of maturation and from 30.20% to 35% in the last harvest. Qualitative and quantitative analysis of phenolic compounds were carried out using HPLC and LC‐MS/MS. Twenty‐six biophenolic compounds were identified. In all samples, hydroxytyrosol and oleuropein were the major compounds identified while rutin and luteolin 7‐O‐glucoside were the two main flavonoids. The total phenolic content varied from 3.46 to 4.30 g kg^?1 at the first stage of maturation and from 8.71 to 11.52 g kg^?1 of fruit fresh weight at the last maturation phase. Total flavonoid content reached 432.80 mg kg^?1. The antioxidant activity of the extract was evaluated by DPPH and ABTS assays. The IC₅₀ values of the olive extracts ranged from 2.69 to 10.96 µg L^?1 and from 2.15 to 3.03 mmol L^?1 trolox equivalent at the last stage of maturation. CONCLUSION: A relationship between the changes in phenolic content and the physicochemical changes in Tunisian olive fruit during maturation was established. These findings could be used for controlling the production processes and correlating the oil sensorial characteristics to the polyphenolic pattern. Copyright © 2010 Society of Chemical Industry     

Transfer of phenolic compounds during olive oil extraction in relation to ripening stage of the fruit

The transfer of phenolic compounds of Olea europaea L. cv. Arbequina variety during olive oil extraction in relation to ripening stage was investigated. The parameters of oil extraction by the Abencor system are shown together with mass balances of the products and by products from the olive oil extraction in relation to olive paste. The phenolic compounds in olive paste, pomace, oil and wastewater were identified and measured by HPLC. Throughout the study, the concentrations of simple phenols, secoiridoids and flavonoids were higher in the olive paste and pomace phases than in oil and wastewater phases. High concentrations of 4‐(acetoxyethyl)‐1,2‐dihydroxybenzene (3,4‐DHPEA‐AC) and secoiridoid derivatives such as the dialdehydic form of elenolic acid linked to 3,4‐DHPEA (hydroxytyrosol) or p‐HPEA (tyrosol) (3,4‐DHPEA–EDA, p‐HPEA–EDA, where EDA is elenolic acid dialdehyde) and an isomer of oleuropein aglycone (3,4‐DHPEA–EA, where EA is elenolic acid aldehyde) were found in olive oil, together with lignan compounds. It was observed that 3,4‐DHPEA–EDA was the most abundant polyphenol present in the wastewater phase. This indicates that biotransformation occurred during olive extraction, especially in the crushing and malaxation operations, and reflects the possible chemical changes that lead to the formation of new compounds. Moreover, the distribution of compounds showed their affinities toward different phases. Copyright © 2005 Society of Chemical Industry     

Evaluation of table olive by‐product as a source of natural antioxidants

The main by‐product from the table olive canning industry is the stone with some residual olive flesh. The purpose of this study was to evaluate the composition – phenolic compounds (hydroxytyrosol, tyrosol and oleuropein) and tocopherol – and the antioxidant activity in different fractions (flesh, stone and seed) from the table olive by‐product and the whole by‐product. The highest amounts of phenolic compounds (1710.0 ± 33.8 mg kg^?1) as well as the highest antioxidant activity (8226.9 ± 9.9 hydroxytyrosol equivalents mg kg^?1) were obtained in the seed. The highest amounts of hydroxytyrosol (854.8 ± 66.0 mg kg^?1) and tyrosol (423.6 ± 56.9 mg kg^?1) were found in the whole by‐product from the pepper stuffed olives, while the stone without seed had the maximum oleuropein content (750.2 ± 85.3 mg kg^?1). α‐Tocopherol values were between 79.8 ± 20.8 mg kg^?1 in the seed of the olive stone and 6.2 ± 1.2 mg kg^?1 in the whole by‐product from the anchovy‐stuffed olives. In light of the results obtained, it would seem possible to use table olive by‐product as a source of natural antioxidants in foods, cosmetics or pharmaceutical products, thus contributing to diminishing the environmental impact of table olive by‐product and to its revalorisation.     

The antioxidant activity and stability of the phenolic fraction of green olives and extra virgin olive oil

The antioxidant activity of phenolic extracts from olives and olive oil has been assessed by scavenging of 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radicals and by studying the effects on the stability of stripped olive oil in the absence and presence of ferric chloride. The olive extracts contained a much higher concentration (1940–5800 mg kg^?1) of phenolic components than the olive oil extract (180 mg kg^?1). Some olive extracts were more effective than the olive oil extract in scavenging DPPH radicals, but the three varieties of olives examined showed relatively large differences in both polyphenol concentration and antioxidant activity of extracts. α‐Tocopherol and extracts from both olives and olive oil were effective antioxidants in stripped olive oil at 60 °C. Ferric chloride reduced the stability of stripped olive oil, but the olive extract studied was significantly more effective as an antioxidant in the presence of the metal salt than the olive oil extract or α‐tocopherol. Ferric ions catalysed the oxidation of caffeic acid, oleuropein and phenolic components of the olive and olive oil extracts in aqueous solution (pH 5.4). The olive extract oxidised more rapidly than the olive oil extract in aqueous solution. © 2001 Society of Chemical Industry     

Contribution of olive seed to the phenolic profile and related quality parameters of virgin olive oil

BACKGROUND: Conflicting results have been reported about the effect of fruit de‐stoning on the virgin olive oil (VOO) phenolic profile. The aim of the present study was to determine whether olive seed plays any role in the synthesis of this oil phenolic fraction. RESULTS: Increases of around 25% of total phenolic compounds were observed in oils obtained from de‐stoned olive fruits in three main Spanish cultivars. To investigate the involvement of olive seed in determining the phenolic profile of VOO, whole intact olive fruits were added with up to 400% olive stones. Excellent regression coefficients were found in general for the decrease of total phenolic compounds and, particularly, of o‐diphenolics in the resulting oils. On the other hand, it was found that olive seed contains a high level of peroxidase (POX) activity (72.4 U g^?1 FW), accounting for more than 98% of total POX activity in the whole fruit. This activity is able to modify VOO phenolics in vitro, similar to the effect of adding stones during VOO extraction. CONCLUSION: Olive seed plays an important role in determining VOO phenolic profile during the process to obtain an oil that seems to be associated with a high level of POX activity. Copyright © 2007 Society of Chemical Industry     

Characterisation and phenolic profiles of two rare olive oils from southern Tunisia: Dhokar and Gemri‐Dhokar cultivars

BACKGROUND: The aim of this work was to study the chemical characteristics of two Tunisian cultivars, namely Dhokar and Gemri‐Dhokar, to analyse the fatty acids, sterols, triacylglycerols, triterpenic alcohols, and to determine the phenolic composition and oxidative stability. RESULTS: Among the rare varieties, Gemri‐Dhokar olive oil had the highest value of oleic acid (69.39%) whereas Dhokar oil was noteworthy for its lower content of phenolic compounds (94.56 mg kg^?1 gallic acid equivalents of oil) and presented the highest level of palmitic acid (19.37%). The main sterols found in all olive oil samples were β‐sitosterol and Δ5‐avenasterol, whereas cholesterol and 24‐methylenecholesterol were also found in all samples but in lower amounts. Two triterpenic dialcohols (erythrodiol and uvaol) were also detected and their content ranged from 1.45 to 2.30%, in Gemri‐Dhokar and Dhokar olive oil, respectively. Ten phenolic compounds were identified. In all samples, the main phenols found were oleuropein aglycon and pinoresinol. These phenolic compounds showed significant correlations with oxidative stability. CONCLUSION: The analytical parameters of two oils that were determined in this study were greatly influenced by genetic factors (cultivar). © 2012 Society of Chemical Industry     

Identification of oleuropein oligomers in olive pulp and pomace

Analysis of a purified fraction from acetone extracts of olive pulp and pomace by electrospray ionisation tandem mass spectrometry (ESI‐MSⁿ) showed the presence of oleuropein oligomers, whose occurrence has not been reported previously in the literature. The main ionic species (m/z 1613) in the ESI‐MS spectrum was an oleuropein trimer containing three linkages through the hydroxytyrosol backbone. In both samples, oleuropein dimers (m/z 1075), trimers comprising two hydroxytyrosol linkages (m/z 1615), tetramers (m/z 2153) and pentamers (m/z 2691) were also detected by MS. The occurrence of oleuropein oligomers was also observed by nuclear magnetic resonance (NMR). ¹³C, ¹³C distortionless enhancement by polarisation transfer DEPT 90, ¹³C DEPT 135, gHSQC (heteronuclear single quantum coherence) and gHMBC (heteronuclear multiple bond coherence) spectra showed all carbon and proton resonances of oleuropein with the exception of the low‐mobility and asymmetric signals of the aromatic rings. Since mature olives were used in this study, it is possible that the disappearance of oleuropein that has been described to occur with the olive fruit maturation, could be associated with the formation of phenolic oligomers together with lower‐molecular‐weight compounds resulting from its degradation. Copyright © 2006 Society of Chemical Industry     

Analytical evaluation of two monovarietal virgin olive oils cultivated in the south of Tunisia: Jemri‐Bouchouka and Chemlali‐Tataouin cultivars

BACKGROUND: The characterisation of virgin olive oils from two Tunisian cultivars, growing in the Tataouin zone, namely Jemri‐Bouchouka, a rare olive cultivar, and Chemlali‐Tataouin, was carried out. Several analytical parameters were evaluated; these include quality index, fatty acids, phenolic, chlorophyll, carotenoid, squalene, α‐tocopherol compositions and oxidative stability. RESULTS: Jemri‐Bouchouka olive oil had the highest value of oleic acid (74.50%) while Chemlali‐Tataouin was characterised by a high percentage of palmitic acid (14.75%), which makes this oil freeze at a low temperature. On the other hand, Jemri‐Bouchouka oil was characterised by a low phenolic and α‐tocopherol content (267.72 mg GAE kg^?1 and 278.34 mg kg^?1, respectively). Ten phenolic compounds were identified. The main phenols found in the two olive oils were oleuropein aglycon and pinoresinol. All phenolic compounds showed significant correlations with oxidative stability. CONCLUSION: The analytical parameters of virgin olive oil that were determined in this study were greatly influenced by cultivar. © 2012 Society of Chemical Industry     

Saturated hydrocarbon content in olive fruits and crude olive pomace oils

Olive fruits contain an n-alkane series of saturated hydrocarbons mainly in the pulp. Lower amounts of a complex mixture of paraffins, unresolved by gas chromatography (UCM – unresolved complex mixture), have been found in cuticle, stone (woody shell and seed), olive leaves, and talc used as an aid to olive oil extraction. The amounts of both kinds of hydrocarbons are related to the olive cultivar and are transferred to oils in a proportion depending on the oil-obtaining process (centrifugation or solvent extraction). In olive oil obtained by centrifugation, only n-alkanes were detected. However, in olive oil extracted by second centrifugation, small amounts of UCM paraffins were detected together with the n-alkanes. Olive pomace oils showed a very variable content of both types of hydrocarbons according to the different obtaining process, such as double centrifugation, solvent extraction or centrifugation followed by solvent extraction. ‘White mineral oil’ used in oil extraction machinery is the source of the high concentrations of UCM paraffins found in some olive and olive pomace oils. In the case of second centrifugation olive oil, a maximum limit of 50 mg kg^?1 of UCM is suggested, whereas in the case of crude olive pomace oil, it amounts to 250 mg kg^?1 plus an additional minimum of 1.0 for the n-alkanes/UCM ratio.     

Addition of enzymes complex during olive oil extraction improves oil recovery and bioactivity of Western Australian Frantoio olive oil

Olive oil consumption has increased as many studies revealed the health benefits of regular consumption of olive oil. There is a need to find effective oil extraction techniques capable of increasing oil recovery without compromising its quality. This study investigated the impact of adding enzymes complex Viscozymes during olive oil extraction on oil recovery, total phenolic compounds, antiradical activity and the standard quality parameters. It was found that at a concentration of 0.30 g mL^?1, Viscozymes could significantly improve the oil recovery from 49 to 69% (P < 0.001) when compared to the Control sample. The concentration of total phenolic compounds was also significantly improved from 110 to 266 mg kg^?1 oil (P < 0.01) and the antiradical activity increased from 31 to 48% inhibition of 2,2‐diphenyl‐1‐picrylhydrazil radical (P < 0.001). Addition of Viscozymes therefore represents an effective extraction technique that increases oil recovery without compromising the concentration of total phenolic compounds and antiradical activity.     

New genotypes of table olives: profile of bioactive compounds

New table olive genotypes (48) coming from a cross‐breeding programme were evaluated. Most of the fruit traits covered a wide range of variability on the set of genotypes, fruit weight (1.1–9.7 g), pulp‐to‐pit ratio (1.7–10.0), fruit shape (1.0–1.6) and oil content (1.3–15.2%). This is the first time that healthy compounds such as triterpenic acids and phenolic compounds have also been evaluated in olive progenies. Genotypes were stored for 2 months in sterilised brine (5% NaCl and 0.5% acetic acid). A high amount of maslinic (685.0–1394.2 mg kg^?1 olive flesh) and oleanolic acids (275.3–817.9 mg kg^?1 olive flesh) was found in the flesh of olives stored. The main oleosidic and phenolic compounds evaluated in brines were hydroxytyrosol (1.9–8.4 mmol L^?1), hydroxytyrosol glucosides (0.4–19.8 mmol L^?1), oleuropein (0.0–4.7 mmol L^?1) and the antimicrobial compounds, dialdehydic form of decarboxymethyl elenolic acid linked to hydroxytyrosol (0.0–3.4 mmol L^?1) and decarboxymethyl elenolic acid (0.0–1.7 mmol L^?1), the latter two being observed in only ten genotypes. The wide range of variation observed for most compounds indicates that the contents of these healthy compounds may be used as selection criteria in table olive breeding programmes.     

Functional compounds from olive pomace to obtain high‐added value foods – a review

Olive pomace, the solid by‐product from virgin olive oil extraction, constitutes a remarkable source of functional compounds and has been exploited by several authors to formulate high value‐added foods and, consequently, to foster the sustainability of the olive‐oil chain. In this framework, the aim of the present review was to summarize the results on the application of functional compounds from olive pomace in food products. Phenolic‐rich extracts from olive pomace were added to vegetable oils, fish burgers, fermented milk, and in the edible coating of fruit, to take advantage of their antioxidant and antimicrobial effects. Olive pomace was also used directly in the formulation of pasta and baked goods, by exploiting polyunsaturated fatty acids, phenolic compounds, and dietary fiber to obtain high value‐added healthy foods and / or to extend their shelf‐life. With the same scope, olive pomace was also added to animal feeds, providing healthy, improved animal products. Different authors used olive pomace to produce biodegradable materials and / or active packaging able to increase the content of bioactive compounds and the oxidative stability of foods. Overall, the results highlighted, in most cases, the effectiveness of the addition of olive pomace‐derived functional compounds in improving nutritional value, quality, and / or the shelf‐life of foods. However, the direct addition of olive pomace was found to be more challenging, especially due to alterations in the sensory and textural features of food. © 2020 Society of Chemical Industry     

Chemical analysis and acetylcholinesterase inhibitory effect of anthocyanin-rich red leaf tea (cv. Sunrouge)

BACKGROUND: The purpose of this study was to evaluate the effects of leaf order or crop season on anthocyanins and other chemicals in the anthocyanin‐rich tea cultivar ‘Sunrouge’ (Camellia sinensis x C. taliensis) by using high‐performance liquid chromatography, and to study the effect of ‘Sunrouge’ extract on acetylcholinesterase (AChE) activity in human neuroblastoma SK‐N‐SH cells. RESULTS: The total anthocyanin content was higher in the third (3.09 mg g^?1) than in the second (2.24 mg g^?1) or first crop season (1.79 mg g^?1). The amount of anthocyanins contained in the stem was high (1.61 mg g^?1). In the third crop season, the concentrations of delphinidin‐3‐O‐β‐D ‐(6‐(E)‐p‐coumaroyl)galactopyranoside (DCGa), cyanidin‐3‐O‐β‐D ‐(6‐(E)‐p‐coumaroyl)galactopyranoside, delphinidin‐3‐O‐β‐D ‐galactopyranoside, delphinidin‐3‐O‐β‐D ‐(6‐O‐(Z)‐p‐coumaroyl)galactopyranoside, cyanidin‐3‐O‐β‐D ‐galactoside, and delphinidin‐3‐O‐β‐D ‐glucoside were 1.57 mg g^?1, 0.52 mg g^?1, 0.40 mg g^?1, 0.22 mg g^?1, 0.14 mg g^?1, and 0.11 mg g^?1, respectively. DCGa accounted for about 50% of the anthocyanins present. The suppressive effect of ‘Sunrouge’ water extract on AChE activity in human neuroblastoma SK‐N‐SH cells was the strongest among the three tea cultivars (‘Sunrouge’, ‘Yabukita’ and ‘Benifuuki’). CONCLUSION: These results suggested that ‘Sunrouge’ might protect humans from humans from AChE‐related diseases by suppressing AChE activity. To obtain sufficient amounts of anthocyanins, catechins and/or caffeine for a functional food material, ‘Sunrouge’ from the third crop season should be used. Copyright © 2012 Society of Chemical Industry     

Characterization of antioxidant olive oil biophenols by spectroscopic methods

BACKGROUND: Olive oil contains numerous phenolic components with well‐recognized health‐beneficial activity. The major phenolic compounds present in olives and virgin olive oil—hydroxytyrosol, oleuropein and the oleuropein aglycones 3,4‐DHPEA‐EA and 3,4‐DHPEA‐EDA—as well as some of their metabolites were studied in the present work, regarding their main structural preferences. Vibrational spectroscopy (Raman) coupled to theoretical methods were used, aiming at fully characterizing the systems and therefore enabling their quick and reliable identification in food samples. RESULTS: The Raman data, assisted by the theoretical simulations, allowed us to obtain the main geometrical and spectroscopic features of the olive oil constituents under study, which determine their known antioxidant and chemoprotective properties. In fact, it was verified that the spectra comprise distinctive bands for each compound, allowing their ready detection and differentiation. CONCLUSION: This is the first reported study on the structural behaviour of olive oil phenolic compounds, and it established Raman spectroscopy as a rapid, non‐destructive and reliable analytical technique for identifying these bioactive components in dietary extracts. It can surpass other analytical methods currently used, once it allows the concomitant identification of several olive oil components in a particular sample. Copyright © 2010 Society of Chemical Industry     

Human absorption and metabolism of oleuropein and hydroxytyrosol ingested as olive (Olea europaea L.) leaf extract

Phenolic compounds derived from the olive plant (Olea europaea L.), particularly hydroxytyrosol and oleuropein, have many beneficial effects in vitro. Olive leaves are the richest source of olive phenolic compounds, and olive leaf extract (OLE) is now a popular nutraceutical taken either as liquid or capsules. To quantify the bioavailability and metabolism of oleuropein and hydroxytyrosol when taken as OLE, nine volunteers (five males) aged 42.8 ± 7.4 years were randomized to receive either capsulated or liquid OLE as a single lower (51.1 mg oleuropein, 9.7 mg hydroxytyrosol) or higher (76.6 mg oleuropein, 14.5 mg hydroxytyrosol) dose, and then the opposite strength (but same formulation) a week later. Plasma and urine samples were collected at fixed intervals for 24 h post‐ingestion. Phenolic content was analyzed by LC‐ESI‐MS/MS. Conjugated metabolites of hydroxytyrosol were the primary metabolites recovered in plasma and urine after OLE ingestion. Peak oleuropein concentrations in plasma were greater following ingestion of liquid than capsule preparations (0.47 versus 2.74 ng/mL; p = 0.004), but no such effect was observed for peak concentrations of conjugated (sulfated and glucuronidated) hydroxytyrosol (p = 0.94). However, the latter peak was reached earlier with liquid preparation (93 versus 64 min; p = 0.031). There was a gender effect on the bioavailability of phenolic compounds, with males displaying greater plasma area under the curve for conjugated hydroxytyrosol (11 600 versus 2550 ng/mL; p = 0.048). All conjugated hydroxytyrosol metabolites were recovered in the urine within 8 h. There was wide inter‐individual variation. OLE effectively delivers oleuropein and hydroxytrosol metabolites to plasma in humans.     

Characterization and fractionation of phenolic compounds extracted from olive oil mill wastewaters

Liquid–liquid extraction was used in order to recover phenolic compounds from olive mill wastewater (OMWW), a polluting by-product of olive oil production process, and the extraction parameters have been optimized. HPLC analysis showed that hydroxytyrosol is the most abundant biophenol in ethyl acetate extracts from an acidified OMWW. Many other biophenols (tyrosol, caffeic acid, vanillic acid, verbascoside, luteolin-7-glucoside, dialdehydic form of decarboxymethyl oleuropein aglycon, ligstroside, luteolin) were identified.     

Quality attributes and their relations in fresh black ripe ‘Kalamon’ olives (Olea europaea L.) for table use – phenolic compounds and total antioxidant capacity

Quality attributes were investigated in fresh Greek black table ‘Kalamon’ olives prior to processing. Fruit weight, dimensions, respiration and ethylene production rates, firmness, peel colour, moisture, oil content, total antioxidant capacity (TAC), the concentration of total phenolics (TP) and phenolic compounds (hydroxytyrosol, oleuropein, tyrosol, verbascoside, luteolin‐7‐O‐glucoside, luteolin, rutin) were determined in olives from different orchards. There was a significant effect of orchard on most attributes, but not on fruit firmness. Verbascoside, oleuropein and hydroxytyrosol were the major phenolics, and the presence of verbascoside in ‘Kalamon’ olives is revealed for the first time. Positive correlations were found among fruit weight, dimensions, respiration and ethylene. TAC was positively related mainly to TP, hydroxytyrosol, verbascoside and rutin, but inversely to oleuropein. Luteolin was inversely related to luteolin‐7‐O‐glucoside. Colour darkening was directly related to TAC, while colour parameters were positively and moderately affected by oil and moisture.     

Distribution of olive oil phenolic compounds in rat tissues after administration of a phenolic extract from olive cake

Scope The distribution and accumulation of olive oil phenolic compounds in the body are topics lacked of information. The aim of this study was to evaluate the bioavailability, metabolism and distribution of phenolic compounds from olive cake. Methods and results The metabolism and distribution of phenolic compounds were examined by UPLC‐MS/MS after an acute intake of a phenolic extract from olive cake, analyzing plasma and tissues (heart, brain, liver, kidney, spleen, testicle and thymus) 1, 2 and 4 h after ingestion using Wistar rats as the in vivo model. The results showed a wide distribution of phenolic compounds and their metabolites in the tissues, with a main detoxification route through the kidneys. Highlighting the quantification of the free forms of some phenolic compounds, such as oleuropein derivative in plasma (Cmax 4 h: 24 nmol/L) and brain (Cmax 2 h: 2.8 nmol/g), luteolin in kidney (Cmax 1 h: 0.04 nmol/g), testicle (Cmax 2 h: 0.07 nmol/g) and heart (Cmax 1 h: 0.47 nmol/g); and hydroxytyrosol in plasma (Cmax 2 h: 5.2 nmol/L), kidney (Cmax 4 h: 3.8 nmol/g) and testicle (Cmax 2 h: 2.7 nmol/g). Conclusion After a single ingestion of olive oil phenolic compounds, these were absorbed, metabolized and distributed through the blood stream to practically all parts of the body, even across the blood‐brain barrier.     

Influence of ethanol/water ratio in ultrasound and high‐pressure/high‐temperature phenolic compound extraction from agri‐food waste

The valorisation and management of agri‐food waste are currently hot investigation topics which probe the recovery of valuable compounds, such as polyphenols. In this study, high‐pressure/high‐temperature extraction (HPTE) and ultrasound‐assisted extraction (UAE) have been used to study the recovery of phenolic compounds from grape marc and olive pomace in hydroalcoholic solutions. The main phenolic compounds in both extracts were identified by HPLC‐DAD. Besides extraction yield (total polyphenol and flavonoid content) and the antiradical power, polyphenol degradation under HPTE and UAE has also been studied. HPTE with ethanol 75% gave higher phenolic extraction yields: 73.8 ± 1.4 mg of gallic acid equivalents per gram of dried matter and 60.0 mg of caffeic acid equivalents per gram of dried matter for grape marc and olive pomace, respectively. In this study, the efficient combination of ethanol/water mixture with HPTE or UAE has been used to enhance the recovery of phenolic compounds from grape marc and olive pomace. HPLC‐DAD showed that UAE prevents phenolic species degradation damage because of its milder operative conditions.     

Phenolics and antioxidative activities in common beans (Phaseolus vulgaris L)

Six bean cultivars grown in southern Manitoba for 2 years were evaluated for variability in yield of millstreams and phenolic constituents. The ethanolic extract of bean cultivars and millstreams was screened for antioxidant activity using the β‐carotene‐linoleate and the 1, 1‐diphenyl‐2‐picrylhydrazyl (DPPH) in vitro model systems. Cultivar was the main source of variation for yield of millstreams, content of phenolic compounds and antioxidant activities. Phenolic compounds in cultivars varied from 3.3 to 16.6 mg catechin equivalent and from 0.15 to 0.32 mg cyanidin‐3‐glucoside equivalent g^?1 bean for total phenolic and anthocyanin contents, respectively. The bean cultivars exhibited antioxidant activity (AA) of 10–46% inhibition of lipid peroxidation in the linoleate and 0.4–1.3 trolox equivalent antioxidant capacities (TEAC) in the DPPH model systems. The hull millstream with maximum concentration of phenolic compounds exhibited the strongest antioxidant activity of 383 µM trolox equivalent g^?1 hull. Total phenolic content, alone or in combination with other phenolic constituents, is a potential candidate as a selection criterion for antioxidant activity in beans. Copyright © 2005 Society of Chemical Industry