Improved loquat (Eriobotrya japonica Lindl.) cultivars: Variation of phenolics and antioxidative potential

Leaves and fruits (peel and flesh) of six improved cultivars (‘Mizuho’, ‘Néctar de Cristal’, ‘Mizauto’, ‘Mizumo’, ‘Centenária’ and ‘NE-3’) of loquat (Eriobotrya japonica Lindl.) were studied for their phenolic composition and antioxidant capacity. The analysis by HPLC-DAD-ESI-MS/MS allowed the identification of 18 compounds (8 hydroxycinnamic acid derivatives and 10 flavonoid glycosides). The quantification of the identified compounds revealed distinct profiles amongst the three analysed materials. Loquat leaves exhibited the lowest amounts of phenolics. 3- And 5-caffeoylquinic, and 5-feruloylquinic acids were the major compounds. Generally, ‘Mizauto’ cultivar presented the highest phenolic content. All loquat materials exhibited DDPH scavenging capacity, in a concentration-dependent manner, the leaves being the most active one. This effect seems to be related to the flavonoid content.     

Kneading olive paste from unripe ‘Picual’ fruits: I. Effect on oil process yield

Olive growers start earlier to harvesting in order to obtain high quality oils, however unripe olives show different characteristics affecting technological and rheological properties. This work is aimed to study the effect of malaxation conditions on process oil yield for unripe ‘Picual’ olives. Experiments were carried out using Picual fruits harvested at early dates for three consecutive crops seasons. The malaxation conditions assayed using a factorial design were: time (60, 90 min), temperature (18, 30, 40 °C) and micronised talc addition (0, 1%). Olive paste from unripe Picual fruit are classified as difficult pastes. The main factor affecting oil yield was the crop year, while for each crop year the effect of each factor varied considerably. Results indicated as increasing time and temperature gave lower pomace oil losses although its effect varied on crop year. Micronised Natural Talc addition lowered pomace oil content on dry weight. Therefore for early harvesting dates knowing olive characteristics ‘on line’ is essential to adapt the kneading conditions.     

How much do cultivar and preparation time influence on phenolics content in walnut liqueur?

The influence of cultivar and picking date on the phenolic content of walnut liqueur was investigated using HPLC with a PDA detector. Ten phenolic compounds, namely gallic, protocatechuic, ellagic, chlorogenic (5-caffeoylquinic), syringic, p-coumaric and sinapic acids, as well as (+)-catechin, 1,4-naphthoquinone and juglone were detected. The walnut liqueur under analysis was made of the cultivars ‘Franquette’ and ‘Elit’, on two sampling dates (June 30th and July 7th). A close interaction between cultivar and sampling date was noticed for most of the phenolics analyzed. The content levels of the main phenolic compounds under investigation were highest in ‘Franquette’ at the end of June and lowest in ‘Elit’ on the second or both sampling dates, except for syringic acid. A strong influence of cultivar choice and picking date was observed. The content levels of most phenolics were higher in liqueur prepared from the cultivar ‘Franquette’, than in ‘Elit’.     

Chicoric acid found in basil (Ocimum basilicum L.) leaves

This is the first report to identify the presence of chicoric acid (cichoric acid; also known as dicaffeoyltartaric acid, which is a caffeic acid derivatized with tartaric acid) in basil leaves. Rosmarinic acid, chicoric acid and caftaric acid (in the order of most abundant to least; all derivatives of caffeic acid) were identified in fresh basil leaves. Rosmarinic acid was the main phenolic compound found in both leaves and stems. Chicoric acid was not detected in sweet basil stems, although a small amount was present in Thai basil stems. Other cinnamic acid monomers, dimers and trimers were also found in minor quantities in both stems and leaves. Basil polyphenolic contents were determined by blanched methanol extraction, followed by HPLC/DAD analysis. The characterization of the polyphenolics found in the basil extracts were performed by HPLC/DAD/ESI–MS/MS and co-chromatographed with purchased standard. The influence of inoculation with an arbuscular mycorrhizal fungus (AMF), Glomus intraradices, on plant phenolic composition was studied on two basil cultivars,‘Genovese Italian’ and ‘Purple Petra’. Inoculation with AMF increased total anthocyanin concentration of ‘Purple Petra’ but did not alter polyphenolic content or profile of leaves and stems, of either cultivar, compared to non-inoculated plants. In the US diet, basil presents a more accessible source of chicoric acid than does Echinacea purpurea, in which it is the major phenolic compound.     

Volatile phenols in virgin olive oils: Influence of olive variety on their formation during fruits storage

The potential significance as odorants and markers of olive fruits degradation has been recently pointed out for volatile phenols in virgin olive oil (VOO) and related to the appearance of VOO sensory defects. The few studies carried out in order to elucidate the factors affecting their formation in olive fruits or VOOs, indicated that they could be considered as analytical indices of olive fruits degradation during storage, likely reflecting the microbiological activity. In the present study, the effect of the olive variety (‘Arbequina’, ‘Arbosana’ and ‘Leccino’) on the production of volatile phenols during twelve days of storage in closed plastic bags was evaluated. The different resistance of each variety to the microbiological attach was observed during olive fruit storage, and it was reflected by the evolution of guaiacol, 4-ethylphenol and 4-ethylguaiacol, and related to free acidity values. On the contrary, a scarce dependence on the microbial growth or varietal factors was observed for 4-vinyl derivatives, which appeared more directly related to the time of olives storage. The evolution of volatile phenols found certain correspondence in the sensory characteristics of the resulting VOOs, while the rest of VOO chemical quality indices did not show major variations during fruits storage.     

Tunisian table olive phenolic compounds and their antioxidant capacity

ABSTRACT:  For the 1st time, 4 olive cultivars, the Meski, Chemlali, Besbessi, and Tounsi, from the Tunisian market were investigated to evaluate the phenolic compounds' contribution in nutritional value of table olives. From the Meski cultivar, we have chosen 4 different samples to evaluate differences within the same cultivar. Basic characteristics and total phenolic content were evaluated in flesh and kernel. The highest value of flesh phenolic content was observed in sample M4 of the Meski cultivar; however, the lowest value was observed in the Besbessi cultivar and they were 1801 and 339 mg GA/100 g dry weight, respectively. The main simple phenolic compounds identified in flesh extracts are hydroxytyrosol, tyrosol, and vanillic acid. Oleuropein was not detected in any samples. The antioxidant activity of Tunisian olive flesh varies between 212 and 462 μM TEAC/g of dry weight. Antioxidant activity of olives was related to their phenolic content but we found a low correlation between phenolic content and TEAC.     

HPLC–MS identification of phenols in hazelnut (Corylus avellana L.) kernels

In whole hazelnut kernels, as the main product of hazelnut (Corylus avellana L.), phenols were analysed in 20 hazelnut cultivars by high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS). Twenty-three compounds from different phenolic groups were detected, and 15 of them were identified. In hazelnut kernels, these substances were detected: nine flavan-3-ols, two benzoic acids (gallic and protocatechuic acid), three flavonols and phloretin glycoside. Total phenol concentrations ranged from 70 to 478 mg gallic acid equivalents per kg hazelnut kernels. A high content level of total phenols was observed in the ‘Tonda Gentile delle Langhe’ and ‘Lewis’ cultivars, which was followed by the ‘Corabel’, ‘Fertile de Coutard’, ‘Daria’ and ‘Tonda Gentile Romana’ cultivars. Similarly, the highest antioxidative activity, measured by employing DPPH-antiradical assay, was also found in the ‘Tonda Gentile delle Langhe’ cultivar, followed by the ‘Fertile de Coutard’.     

Comparative study of primary and secondary metabolites in 11 cultivars of persimmon fruit (Diospyros kaki L.)

Primary metabolites (sugars, organic acids) and secondary metabolites (phenolics and carotenoids) were quantified by HPLC in fully ripe fruit of 11 kaki cultivars: ‘Amankaki’, ‘Cal Fuyu’, ‘Fuji’, ‘Hana Fuyu’, ‘Jiro’, ‘O’Gosho’, ‘Tenjin O’Gosho’, ‘Thiene’, ‘Tipo’, ‘Tone Wase’ and ‘Triumph’. Amongst the analysed cultivars, ‘Tone Wase’ stands out as the richest in sugars, particularly glucose, and cultivars ‘Tipo’ and ‘Triumph’ contained the highest amounts of organic acids. Cultivars ‘O’Gosho’, ‘Cal Fuyu’ and ‘Hana Fuyu’ contained the least sugars and cultivar ‘Jiro’ the least organic acids. Amongst the individual phenolic compounds catechin and gallic acid were present in highest concentrations. The predominant carotenoid in both skin and pulp of ripe persimmon fruit was β-carotene, the highest content was measured in skin of cultivar ‘Hana Fuyu’, which also contained the highest level of total carotenoids. In persimmon pulp, much lower values for carotenoids were obtained, particularly in fruit of cultivar ‘Cal Fuyu’.     

Phenolic composition, isolation, and structure of a new deoxyloganic acid derivative from Dhokar and Gemri-Dhokar olive cultivars

Two rare olive cultivars, Dhokar and Gemri-Dhokar, growing in the south of Tunisia were investigated to identify their phenolic profile and evaluate their sugar content and antioxidant activity. The highest value of phenolic content was detected in Gemri-Dhokar cultivar extract (6.97 g gallic acid equivalents/kg of fresh olive). In addition, sugar content was quantified; glucose (45.17 g/kg of fresh olive) was the predominant sugar in Dhokar cultivar, followed by fructose (40.83 g/kg of fresh olive). The identification of phenolic compounds was based on separation by high-performance liquid chromatography equipped with a diode array detector followed by liquid chromatography-mass spectrometry analysis. In both cultivars, Oleuropein aglycon derivatives and elenolic acid were the main phenolic components. Oleuropeins were the major compounds quantified in the Gemri-Dhokar drupes olives (61.04 mg/100 g of fresh olive), while 0.25 mg/100 g were found in fresh Dhokar. A new iridoid compound, isolated as pure compound, was not previously reported in the literature. Its structure was established by spectroscopic analyses (NMR, UV, MS, and IR). DPPH, ABTS, and FRAP assays showed that the most important antioxidant capacity of olive extracts was found in with Gemri-Dhokar cultivar.     

Quality analysis of ‘Redhaven’ peach fruit grafted on 11 rootstocks of different genetic origin in a replant soil

The fruit quality of ‘Redhaven’ peach [Prunus persica (L.) Basch.] grafted on 11 (Adesoto, Julior, GF 677, Monegro, Barrier 1, Cadaman, MrS 2/5, Ishtara, Penta, Tetra and peach seedling) experimental rootstocks was evaluated in 2008 under replant orchard conditions. Several quality indices [weight, flesh firmness (FF), ground colour measurements, and soluble solids content (SSC)] were measured, and HPLC analysis were performed for numerous chemical parameters (quantification of individual sugars, organic acids, phenolic compounds in skin and in pulp). Total phenolic content and antioxidant capacity in skin and in pulp were also measured. Julior had the heaviest fruit, while Barrier 1 and GF 677 produced fruit lighter in weight. Rootstocks influenced harvest maturity. Monegro produced the least ripe fruit, characterised by high FF, phenolic compounds in the skin and low SSC. Adesoto rootstock resulted in the best overall fruit quality (high values of SSC, individual and total sugar content levels, individual and total organic acids and phenolic compounds in pulp) as well as high total yield. Julior rootstock also produced good quality peach (high values of SSC, individual and total sugars). Cadaman and peach seedling rootstock produced ‘Redhaven’ fruit of the lowest quality, indicated by low values of sugars, organic acids, phenolic compounds in pulp and in skin.     

Flavonoid constituents and their contribution to antioxidant activity in cultivars and hybrids of rabbiteye blueberry (Vaccinium ashei Reade)

Fruit from 42 blueberry (Vaccinium spp.) cultivars, including 36 rabbiteye cultivars (Vaccinium ashei Reade), three V. ashei hybrid derivatives, and three northern highbush (Vaccinium corymbosum L.) standards were evaluated for antioxidant capacity, individual flavonoid content, and the contribution of each identified phenolic compound to total antioxidant activity. Considerable variation was found in flavonoid content, antioxidant activity, and their contribution to total antioxidant activity among cultivars. Among 42 blueberry cultivars, the rabbiteye ‘Early May’ contained the highest amount of chlorogenic acid, myricetin 3-arabinoside, quercetin derivatives, and delphinidin-, cyanidin-, petunidin-, and malvidin-basis anthocyanins. ‘Early May’ cultivar also had the highest antioxidant activity (88.2 μmol TE/g fw). ‘Owen’, ‘Bluegem’, ‘Clara’, Climax’, and ‘Centurion’ were among the other rabbiteye cultivars that also had high levels of flavonoids and antioxidant activities. In contrast, the pink-fruited V. ashei hybrid, ‘Pink Lemonade’, had the lowest content of flavonoids and lowest antioxidant activity. The mean flavonoid content and antioxidant activity of rabbiteye cultivars was higher than those among northern highbush and V. ashei hybrids. The antioxidant activity of V. ashei hybrid derivatives was derived mainly from chlorogenic acid, myricetin, and quercetin, which contributed 62.5% of total antioxidant activity, whereas anthocyanins (malvidin, petunidin, delphinidin, and cyanidin) were the main contributors to the antioxidant activity of rabbiteye cultivars (76.2%) and northern highbush standards (76.8%). Blueberry cultivars identified to have high phenolic content and high antioxidant activity could be used as parents for future blueberry breeding programmes to develop new blueberry cultivars with higher antioxidant activity and further improve human health.     

Comparative study of improved vs. traditional apple cultivars and their aptitude to be minimally processed as ‘ready to eat’ apple wedges

The development of fresh-cut apple products requires the reconsideration of cultivar selection because different characteristics are required compared with those characteristics for the fresh market. The aim of this work was to evaluate four improved cultivars (‘Modì’, ‘Ariane’, ‘Fuji Kiku 8’ and ‘Pink Lady’) and to compare these cultivars with traditional cultivars (‘Golden Smoothee’ and ‘Granny Smith’). Cultivars were evaluated according to physicochemical parameters and nutritional, enzymatic, and sensory aspects. Next, the cultivars were peeled, cut, treated with different antioxidant treatments, packaged in polypropylene trays and stored at 4 °C. After seven days of storage, physicochemical parameters and visual assessment were determined. As whole apples, the improved cultivars were notable for their sensory characteristics. Moreover, two of them (‘Modì’ and ‘Ariane’) presented the highest amount of total phenols and vitamin C, respectively. After processing and storage, certain of the improved cultivars presented better aptitude for minimal processing. For instance, ‘Modì’ showed high suitability, and ‘Fuji Kiku 8’ was notable for its sensory quality after seven days of refrigerated storage. Among antioxidant treatments that were assayed, 40 g/L NatureSeal^® demonstrated the best results in terms of physicochemical parameters, visual assessment and sensory quality.     

Minor compounds in the phenolic fraction of virgin olive oils

The phenolic fraction of 34 virgin olive oils was analysed by gas chromatography–mass spectrometry (GC–MS) with the aim to identify new compounds at low level. Twenty-seven compounds previously described in olive oils were identified; several new minor compounds with phenolic structure were detected in the samples: amongst them, 4-hydroxyphenylacetaldehyde, trans-isoeugenol (trans-2-methoxy-4-(1-propenyl)-phenol), 1,4-dihydroxy-2,6-dimethoxybenzene, 3,4-dihydroxybenzyl alcohol and 3,4-dihydroxyphenylacetic acid were identified by their mass spectra and confirmed using standards. In 34 virgin olive oils (cv. Nocellara del Belice) the mean concentrations for these five substances were always below 0.2 mg kg⁻¹ and only in two samples the level of 3,4-dihydroxyphenylacetic acid reached 1.47 and 1.97 mg kg⁻¹, respectively. These compounds could be used to characterise olive oils; low concentrations of 3,4-dihydroxyphenylacetic acid may show the initial autoxidation processes of olive oils.     

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     

Effects of olive paste fast preheating on the quality of extra virgin olive oil during storage

The olive paste obtained after crushing was fast preheated under different time/temperature conditions and then malaxed in an industrial oil mill (600 kg Frantoio/Leccino olive blend). Legal parameters (peroxides, free acidity and sensory panel), oil yield, total phenolic content, oxidative stability and phenolic profile were monitored during 12 months of storage of the virgin olive oil (VOO) kept in closed bottles in the dark. A fast preheating not longer than 72 s at 38 °C without malaxation lead to an extra VOO with a shelf-life of at least 12-months, similarly to the traditional EVOO obtained with malaxation. A fast preheating not longer than 72 s at 38 °C followed by 10 min malaxation lead to an EVOO with a ‘mild’ sensory profile and a shelf life of at least 12-months. Thus, the use of a specific designed fast preheater instead or before (a shortened) malaxation allows to obtain an EVOO with a low bitter/pungent attribute from olives which are rich of (sometimes unpleasant) phenolic compounds with the aim to meet the preference of targeted groups of consumers. Time and temperature of fast preheating are the critical parameters of the process.     

Phenolic compounds in virgin olive oils: influence of the degree of olive ripeness on organoleptic characteristics and shelf-life

 An experimental investigation was performed on virgin olive oils from Coratina and Ogliarola salentina cultivars extracted from green, partially blackened and totally blackened olives in order to evaluate changes in the organoleptic properties and in the shelf-life of the oil. The aim of the investigation was to identify the optimal stage of olive maturation for each cultivar to produce higher quality oils. Routine analyses in accordance with EC regulation no. 2568/91, the determination of phenols by HPLC and induction times were carried out. On the whole, the simple phenolic compounds increased as darker olives were used whereas the hydrolysable phenolic compounds decreased. In both the cultivars, total phenols and induction times were significantly higher in the oils obtained from green olives than in oils from totally blackened olives. Hence, it seems advisable to delay olive harvesting for cultivars usually yielding bitter to pungent oils (e.g. Coratina), but to anticipate harvesting for olives producing sweet tasting oils (e.g. O. Salentina). This would produce less bitter Coratina oils, with organoleptic features which may better fulfil consumers' expectations, and O. Salentina oils more resistant to oxidation. Received: 5 June 2000     

‘Liking’, ‘Buying’, ‘Choosing’ and ‘Take Away’ preference tests for varying degrees of hedonic disparity

Paired preference tests of liking require consumers to specify which of two foods are preferred or whether there is no preference. For ‘Buying’ preference tests, consumers specify which of two foods they are more likely to buy or whether they might buy either or neither. For ‘Choosing’ preference tests, consumers specify which of two foods they are more likely to choose when offered both, or whether they might choose both or neither. The first test is designed to predict greater degrees of liking, the second to predict buying behavior and the third to predict choice behavior. Yet, test results may not necessarily predict ‘real life’ behavior once consumers have left the testing situation; the ‘test’ preferences may not be ‘operational’. To validate the predictive ability of such tests, consumer behavior should be monitored for several months. Another approach is to allow consumers to take away some of the foods used in the test and observe what they take away. Consumers of potato chips were required to taste chips whose flavor and appearance were obviously different. A first group (N = 107) were given ‘Liking’, ‘Buying’ and ‘Choosing’ preference tests for two palatable types of chip. After the test, out of sight of the experimenter, consumers were presented with two rows of plain plastic ‘snack’ bags, filled with the chips used in the test. They could take away either two bags of the same type of chip (a ‘Take Away’ preference) or one of each type (no ‘Take Away’ preference) or take neither (rejection). They were also subtly questioned regarding whether they were going to consume the chips themselves or were going to share them with friends. A second group (N = 103) repeated the experiment. However, for these consumers, one type of chip was unpalatable. In general, ‘Buying’ preferences corresponded more to ‘Take Away’ preferences while ‘Liking’ and ‘Choosing’ preferences showed little correspondence. For the palatable chips, the preferences were spread more evenly than for the case where one type of chip was undesirable. In this latter case, approximately 50% of consumers were consistent over all tests in choosing the palatable chip. This might suggest operational preferences. ‘Take Away’ preferences suggested low predictability for paired preference tests of liking, choosing and buying. ‘Take Away’ preferences are not a substitute for monitoring consumer behavior for several months but they are a step in the right direction.     

Nutritional components and anti-oxidant capacity of ten cultivars and lines of cactus pear fruit (Opuntia spp.)

Cactus pear fruit (Opuntia) are harvested from various species of the genus Opuntia of the cactus family (Cactaceae), and are produced and consumed in several countries. We have characterized the nutritional content and antioxidant capacity (AC) of the fruit of ten cultivars/lines of distinct pulp colors. ‘Camuesa’ had the highest betalains, total carotenoids, ß-carotene, ascorbic acid, and was one of the highest in total phenolic compounds, but its AC did not demonstrate outstanding differences with some other cultivars/lines that were not as rich in these compounds. ‘Roja Pelota’ had high AC when measured with the DPPH assay, but had low total carotenoids, ß-carotene and total phenolic content. ‘Reyna’ had slightly low AC as measured by the FRAP assay, practically no betalains, and low vitamin C, tocopherols, ß-carotene, and total phenolic content.