Juice components and antioxidant capacity of four Tunisian Citrus varieties

BACKGROUND: Juices from four Citrus species of Tunisia were investigated mainly for quality parameters and antioxidant capacity. RESULTS: Citrus reticulata (mandarin) juice had the highest content of total flavonoids (85.33 mg CE L^?1). The latter also occurred in high quantity (82.01 mg CE L^?1) in Citrus lemon (lemon) juice which was also marked by its richness in total aroma (70.16 µg mL^?1) and in total fatty acids (48.10 µg mL^?1). Mandarin and lemon juices had the highest antioxidant activity, as determined b the β‐carotene bleaching assay (26.67% and 22.67%, respectively). Citrus aurantium (bitter orange) juice was characterised by the highest content of total polyphenols (784.67 mg GAE L^?1) and by the greatest inhibition of DPPH (96.10%). Citrus sinensis (blood orange) juice was only marked by the high quantity of ascorbic acid (36.90 mg mL^?1). GC/MS analysis of juice aroma showed the predominance of limonene (48.85–69.59%) in mandarin and in bitter and blood oranges, but of camphene (89.05%) in lemon. GC analysis of juice fatty acids revealed their richness in oleic acid (23.13–39.52%). HPLC analysis of juice phenolics indicated the predominance of phenolic acids (73.13–86.40%). CONCLUSION: The Citrus species used in this study were considered valuable varieties from the point of view of antioxidant capacity and nutrition. Copyright © 2010 Society of Chemical Industry     

Comparative study on the antioxidant capacity and cholinesterase inhibitory activity of Citrus aurantifolia Swingle, C. aurantium L., and C. bergamia Risso and Poit. peel essential oils

Abstract: The interest in medicinal plant research and in the aroma‐therapeutic effects of essential oils in humans has increased in recent years, especially for the treatment of pathologies of relevant social impact such as Alzheimer's disease. The present study was taken up to evaluate the antioxidant capacity and the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity of the peel essential oils from three Citrus species, C. aurantifolia Swingle, C. aurantium L., and C. bergamia Risso & Poit. Essential oils were analyzed by GC and GC‐MS and they contain mainly limonene, α‐pinene, β‐pinene, γ‐terpinene, and linalyl acetate. C. aurantifolia oil showed the highest radical scavenging activity on ABTS assay (IC₅₀ value of 19.6 μg/mL), while C. bergamia exhibited a good antioxidant activity evaluated by the β‐carotene bleaching test (IC₅₀= 42.6 μg/mL after 60 min of incubation). C. aurantifolia inhibited more selectively AChE. Obtained data suggest a potential use of Citrus oils as a valuable new flavor with functional properties for food or nutraceutical products with particular relevance to supplements for the elderly. Practical Application: The demonstrated antioxidant activity and procholinesterase properties of Citrus essential oils suggested their use as a new potential source of natural antioxidant to added as extra‐nutrient for using in food industries as a valuable new flavor with functional properties for food or nutraceutical products with particular relevance to supplements for the elderly.     

Volatile fraction composition and physicochemical parameters as tools for the differentiation of lemon blossom honey and orange blossom honey

BACKGROUND: Volatile fraction profile and physicochemical parameters were studied with the aim of evaluating their effectiveness for the differentiation between lemon blossom honey (Citrus limon L.) and orange blossom honey (Citrus spp.). They would be useful complementary tools to the traditional analysis based on the percentage of pollen. RESULTS: A stepwise discriminant analysis constructed using 37 volatile compounds (extracted by purge and trap and analysed by gas chromatography–mass spectrometry), and physicochemical and colour parameters (diastase, conductivity, Pfund colour and CIE L*a*b*) together provided a model that permitted the correct classification of 98.3% of the original and 96.6% of the cross‐validated cases, indicating its efficiency and robustness. This model proved its effectiveness in the differentiation of both types of honey with another set of batches from the following year. CONCLUSION: This model, developed from the volatile compounds, physicochemical and colour parameters, has been useful for the differentiation of lemon and orange blossom honeys. Furthermore, it may be of particular interest for the attainment of a suitable classification of orange honey in which the pollen count is very low. These capabilities imply an evident marketing advantage for the beekeeping sector, since lemon blossom honey could be commercialized as unifloral honey and not as generic citrus honey and orange blossom honey could be correctly characterized. Copyright © 2011 Society of Chemical Industry     

Use of HS‐SPME‐GC‐MS for the classification of Italian lemon,orange and citrus spp. honeys

Volatile compounds from 90 Italian citrus honeys of different varieties (lemon, Citrus limon (L.) Burm., orange, Citrus sinensis (L.) Osbeck, and citrus, Citrus spp.), 30 provided by CRA‐API (Consiglio per la Ricerca e la Sperimentazione in Agricoltura‐Unità di ricerca di apicoltura e bachicoltura) (Bologna, Italy) and 60 purchased on the markets, were analysed to classify them according to the characteristic aroma profiles. A HS‐SPME‐GC method previously developed and validated was applied. Factor analysis and general discriminant analysis (GDA) were carried out on peaks and intensity data. Statistical analyses revealed a good separation between samples; the best model based on peaks data shows 66.5% and 33.5% of total variance explained by the first and the second canonical functions and a predictive capacity of 78.9%. Regarding the intensity data, the CFs of the GDA model explain 53.8% and 46.2% of the total variance and the crossvalidation shows a predictive capacity of 96.7%.     

Elucidation of key aroma enhancement in cloudy lemon juices by the addition of peel oil using GC–MS-Olfactometry

Volatile substances play a crucial role in the consumer preference of lemon juices. The effects of heat treatment and addition of lemon peel oil to lemon juice (Citrus limon Burm. cv. Kutdiken) on the aroma compounds were elucidated for the first time. Total phenolic, antioxidant activity, acidity, pH and colour properties were also studied. Results revealed that the aroma of the juice samples comprised mostly the terpene compounds. Limonene, γ-terpinene, β-pinene and α-pinene were the influential terpenes responsible for the distinctive odour of the lemon juice. The addition of the lemon peel oil increased the amounts of the aroma and aroma-active compounds. Besides, the heat treatment had a positive effect on the total phenolics and the antioxidant activity but it caused significant reduction of the aroma compounds. Sensory analysis revealed that the most preferred sample was the juice with lemon peel oil added after pasteurisation.     

湖北烟区烤烟质量综合评价及典型相关分析

对湖北烤烟外观质量、化学成分和感官质量状况进行分析,并与津巴布韦烤烟进行比较,结果表明:1)湖北烤烟颜色柠檬黄-橘黄,结构疏松,身份适中;香气质好量足,杂气较轻,余味较舒适,配伍性强.与津巴布韦烤烟相比较,外观及感官质量仍有一定差距:在颜色、成熟度和刺激性上的差异达到0.05显著水平;在结构、香气质、香气量、杂气和余味上的差异达到0.01显著水平;化学成分含量及其比值与津巴布韦烤烟差别不大.2)烤烟外观质量与感官质量关系密切,两者间的典型相关主要是由外观质量中的颜色、成熟度、结构、身份、油分和色度及感官质量中的香气质、香气量和杂气相关决定的.化学成分与感官质量的典型相关主要是由化学成分中的烟碱、总氮、糖碱比和氮碱比与感官质量中的香气质、刺激性和余味相关决定的.     

水蒸汽蒸馏法提取柑桔类果皮香精油的工艺研究

本文研究了利用水蒸汽蒸馏法从沙田柚皮、芦柑皮、柠檬皮中提取香精油的工艺.考察了各种因素对得油率的影响.结果表明:沙田柚皮、芦柑皮、柠檬皮的最佳提取时间是90 min;适当破碎果皮可以提高得油率,但破碎度过大反而使得油率降低;烘干的沙田柚皮、芦柑皮、柠檬皮的得油率分别比新鲜的提高了55.2 %、19.5 %、77.5 %,但香精油的质量比新鲜的差;添加助剂氯化钠、硫酸钠、碳酸钙能提高沙田柚皮和柠檬皮的得油率,但不能提高芦柑皮的得油率.     

Assessment of the Variations in Selected Industrially Desirable Morphological and Biochemical Traits of Eleven Citrus Species in Sri Lanka

The fruits with nutraceutical and medicinal values are having a greater significance in modern food industry. Out of many fruit tree bearing genera, the genus Citrus is extremely important in this regard. It contains well known species such as orange, lime, mandarin, lemon and many other underutilized species. The nutritive value of Citrus is given by many bioactive compounds present in the fruits such as alkaloids, tannins, phenols and saponins. In Sri Lanka, the available Citrus germplasm is not characterized in detail. Especially underutilized Citrus species are yet to receive a proper taxonomic identity. Therefore in the present study we report some of the important morphological and biochemical traits of eleven Citrus species. The fruit size traits; weight, height and width were very highly variable among the studied genotypes and positively correlated to each other (P<0.05). However, juice volume was not highly correlated with the other fruit size traits. The juice volume per unit fruit weight can be given as a better indicator for the selection of these species for industrial applications. Pummelo, a popular edible Citrus fruit, showed the lowest volume to weight ratio of 0.06. The size of the endocarp cells (i.e. juice sacks) was also very highly variable among genotypes / species studied. The brix value, a parameter of total soluble solids, was highest in Sidaran fruits (8.07%) and lowest in cooking types such as lemon and lime (3.27% and 3.76% respectively). Similarly the ascorbic acid concentration was also lowest in lime and lemon (1.9 and 1.5 mM respectively). The sweet orange cultivar Sisila (5.9 mM) and Pummelo (6.9 mM) had the highest ascorbic acid concentrations. The results reported here are very useful to select these genotypes / species for potential industrial applications, future genetic and breeding studies and to further characterize at molecular level to establish an accurate taxonomic scheme for Sri Lankan Citrus germplasm which will be the next focus of our group.     

Untersuchungen zum Einflu? von Citrus?len auf die Atmung von Trichoderma lignorum

Zusammenfassung a) Orangenöl und Zitronenöl wirken in bestimmten Konzentrationsbereichen hemmend auf die Atmung vonT. lignorum. Die Hemmwirkung des Orangenöls beruht im wesentlichen auf die vond-Limonen. Zitronenol besteht aus verschiedenen Komponenten, von denen die Hemmwirkung desd-Limonens und-Pinens nachgewiesen werden konnte. Zitronenöl kann die Atmung bei höheren Konzentrationen fast völlig blockieren. b) Ein synergistischer Effekt von Zitronenöl und Natrium-o-Phenylphenolat (SOPP) auf die Atmung vonT. lignorum ist nicht zu beobachten.

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Influence of citrus oils in respiration of trichoderma lignorum

Summary a) The effect of orange oil and lemon oil on respiration ofT. lignorum is an inhibiting effect of both substances at definite concentration ranges. The inhibition of orange oil is caused byd-limonene. Lemon oil consists of different compounds, of whichd-limonene and-pinene inhibited as demonstrated. At higher concentrations lemon oil is able to induce a total block of respiration. b) A synergistic effect of lemon oil and sodium-o-phenylphenolate (SOPP) on respiration ofT. lignorum cannot be observed.

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Die vorliegenden Untersuchungen wurden mit Unterstützung eines Grant des US-Department of Agriculture Nr. FG-Ge-102 durchgeführt.     

Volatile constituents of roasted tigernut oil (Cyperus esculentus L.)

BACKGROUND: Volatile compounds play a key role in determining the sensory appreciation of vegetable oils. In this study a systematic evaluation of odorants responsible for the characteristic flavour of roasted tigernut oil was carried out. RESULTS: A total of 75 odour‐active volatiles were identified. From these, 13 aroma compounds showing high flavour dilution factors in the range of 16 to 128 were quantified by their odour activity values (OAVs). On the basis of high OAVs in oil, the following aroma compounds [vanillin (chocolate, sweet vanilla), 5‐ethylfurfural (caramel, spicy), 2,3‐dihydro‐3,5‐dihydroxy‐6‐methyl‐4H‐pyran‐4‐one (caramel), phenyl acetaldehyde (honey‐like), ethanone, 1‐(4‐hydroxy‐3‐methoxyphenyl) (faint vanilla)] were elucidated as important contributors to the overall chocolate, sweet vanilla, butterscotch aroma of the oil. CONCLUSION: Odorants with high concentrations in the roasted tigernut oil such as 5‐hydroxymethylfurfural, ethyl hexadecanoate, n‐propyl‐9,12‐octadecadienoate gave relatively low OAVs, so their contributions to the overall orthonasal aroma impression of roasted tigernut oil can be assumed to be low. © 2012 Society of Chemical Industry     

Lavender,tea tree and lemon oils as antimicrobials in washing liquids and soft body balms

The aim of this study was to evaluate the antimicrobial activity of commercial essential oils: lavender, tea tree and lemon, antimicrobials in washing liquid and O/W soft body balm. The inhibition efficacy of essential oils in washing liquid (1% alone or in mixtures), in soft body balm (0.5% alone), as well as combined with the synthetic preservative DMDM hydantoin and 3‐iodo‐2‐propynyl butyl carbamate mixture (0.1 and 0.3%), was tested against S. aureus ATCC 6538, P. aeruginosa ATCC 9027, Candida sp. ?OCK 0008 and A. niger ATCC 16404 in compliance with the European Pharmacopoeia standards. The components of the system preserving soft body balm were supplemented with a solubilizer. Washing liquids containing only essential oils met Criterion A E.P. only for S. aureus, Candida sp. and A. niger. In soft body balm formulations, oils at a concentration of 0.5% did not reveal any preserving activity. The introduction of a solubilizer to a system containing 0.5% tea tree oil led to a substantial increase in the bacteriostatic activity of the formulation, but did not significantly affect its fungistatic properties. A combination of 0.5% tea tree oil, 5% solubilizer and 0.3% synthetic preservative ensured the microbiological stability of soft body balm in accordance with Criterion A E.P.     

Impact of minimal heat-processing on pectin methylesterase and peroxidase activity in freshly squeezed <Emphasis Type="Italic">Citrus</Emphasis> juices

The impact of minimal heat-processing of juices on the activities of endogenous pectin methylesterase (PE) and peroxidase (POD) was compared between Citrus species. Mono-cultivar juices were produced from three orange (Citrus sinensis (L.) Osbeck cvs. ‘Navelina’, ‘Salustiana’, and ‘Navelate’), two lemon (Citrus limon (L.) Burm. f. cvs. ‘Verna’ and ‘Primofiori’), and two Clementine mandarin varieties (Citrus reticulata Blanco cvs. ‘Marisol’ and ‘Clemenules’). Two mandarin hybrids (cvs. ‘Ortanique’ and ‘Clemenvilla’) were likewise used. The freshly squeezed juices were subjected to continuous treatments at six different temperatures (42–92 °C) with subsequent re-cooling on the pilot plant scale. In fresh Citrus juice, POD activities notably varied between 0.2 and 7.5 nkat g⁻¹ of juice, whereas PE activities were more uniform (0.4–1.5 PE units g⁻¹). In all juices, except ‘Ortanique’ juice, heating ≥42 °C for 12 s reduced POD activity below 4.3% of the maximum activity in fresh Citrus juice. Thermal tolerance of the thermo-labile PE fraction was overall much higher, but varied among juices during heating at temperatures ≤62 °C. Overall thermal resistance of PE was though comparable, with deactivation exceeding 84%, mostly even 90%, after thermal treatments ≥72 °C. Unlike POD, total PE activity proved to be an indicator of freshness that is universally applicable to Citrus juices derived from orange, mandarin, and lemon or blends thereof. Freshly squeezed juices can analytically be distinguished from cold-stored, minimally processed products that display an almost completely inactivated thermo-labile PE fraction and thus extended shelf life.     

VARIETAL AROMA COMPOUNDS OF VITIS VINIFERA CV. KHAMRI GROWN IN TUNISIA

ABSTRACT

The aroma composition of the grape juice of Khamri, a native variety of Vitis vinifera grown in Tunisia, was investigated for the first time. A total of 27 free and 20 glycosidically bound compounds were identified by gas chromatography‐mass spectrometry. According to the obtained results, the aroma compounds were C6 alcohols, benzene compounds, terpenes, acids and norisoprenoids. On the basis of gas chromatography‐olfactometry, these compounds were grouped, according to volatiles exhibiting the identical odor quality, into 10 groups of the same character (aromatic series) as a way of establishing an aroma profile for the studied variety. The high glycosidically bound norisoprenoid concentrations and the absence of the bound form of the acids were a positive factor for the Khamri variety potential aroma.

PRACTICAL APPLICATIONS

This article aimed on the identification of the unknown Tunisian grapevine varieties that are very well adapted to the arid conditions and that could have a good quality. The discovery of unknown autochthonous grapevine varieties with good aroma and pomological characteristics could be of great importance for the agriculture sector all over the world especially the arid regions.

     

Influence of the different oils used in dough formulation on the lipid fraction of taralli

Abstract: An experimental investigation was carried out to evaluate the quality of taralli as a function of the type of oil used in their dough formulation. To this end, 4 types of oil (extra virgin olive oil, olive oil, olive‐pomace oil, and refined palm oil) were utilized to prepare taralli to investigate on the lipid fraction degradation and evaluate the taralli acceptability by consumers. The data obtained pointed out that taralli manufactured with extra virgin olive oil were significantly more appreciated than those made with refined oils due to their visual appearance and odor. Moreover, with respect to the other kinds of oil, the use of extra virgin olive oil led to significantly lower values (P < 0.05) of specific absorption at 232 and 270 nm (K₂₃₂ and K₂₇₀, respectively) and of triacylglycerol oligopolymers. It also proved to present a much lower content in oxidized triacylglycerols and diacylglycerols than olive‐pomace oil and refined palm oil, respectively. Furthermore, trans fatty acid isomers were absent in taralli made with extra virgin olive oil but were constantly present in those produced with refined oils.     

Characterisation of the key aroma compounds in the peel oil of Pontianak oranges (<Emphasis Type="Italic">Citrus nobilis</Emphasis> Lour. var. <Emphasis Type="Italic">microcarpa</Emphasis> Hassk.) by aroma reconstitution experiments

Nineteen odour-active compounds previously identified with high Flavour Dilution factors in an extract from the peel oil of Pontianak oranges (Citrus nobilis Lour. var. microcarpa Hassk.) were quantified using stable isotope dilution assays (SIDA). For this purpose, four new SIDA were developed, i.e. for the quantification of (E)-2-dodecenal, geraniol, nerol, and 1-phenylethanethiol. The results showed that (R)-limonene, myrcene, and (R)-α-pinene were the predominant compounds present in concentrations between 0.4 and 60 mg/g peel. An aroma recombinate containing the nineteen aroma compounds in the concentrations naturally occurring in the peel oil elicited the overall aroma of the peel oil itself, thus confirming the identification experiments. Furthermore, omission experiments showed that the unique odour quality of the peel is significantly influenced by the resinous, sulphurous-smelling 1-phenylethanethiol, although its concentration was only 38 ng/g peel.     

Characterization and discrimination of premium‐quality,waxy, and black‐pigmented rice based on odor‐active compounds

BACKGROUND: Odor‐active compounds have been studied in cooked aromatic rice, but not in specialty rice types that have distinctly different flavors. We analyzed the odor‐active compounds emanating from three different types of specialty rice (premium‐quality, waxy and black‐pigmented) and identified the differences in odor‐active compounds among them. RESULTS: Twenty‐one, 21 and 23 odorants were detected using GC‐O for cooked samples of premium‐quality, waxy and black‐pigmented rice cultivars, respectively. Hexanal was the main odorant in premium‐quality and waxy cultivars; however, waxy cultivars had 16 times higher hexanal odor activity values (OAVs) than premium‐quality cultivars, indicating premium‐quality rice had a less pronounced overall aroma. 2‐Acetyl‐1‐pyrroline was the main contributor to overall aroma in black‐pigmented rice, followed by guaiacol. The three types of specialty rice were clearly discriminated based on the OAVs of their odor‐active compounds using multivariate analyses. Six odor‐active compounds [2‐acetyl‐1‐pyrroline, guaiacol, hexanal, (E)‐2‐nonenal, octanal and heptanal] contributed the most in discriminating the three types of specialty rice. Six very similar superior cultivars of premium rice could likewise be readily separated using aroma chemistry. CONCLUSION: The ability to discriminate the aroma among rice types using the OAVs of the principal odor‐active compounds facilitates our understanding of the aroma chemistry of specialty rice. Copyright © 2010 Society of Chemical Industry     

The effects of nanoemulsions based on citrus essential oils on the formation of biogenic amines in trout fillets stored at 4 ± 2°C

The influences of nanoemulsions based on citrus peel (orange, lemon, mandarin, and grapefruit) essential oils on the biogenic amine (BA) formation in rainbow trout (Oncorhynchus mykiss) fillets stored 4 ± 2°C were investigated. The results demonstrated that main BAs in the trout fillets were putrescine, cadaverine, spermidine, spermine, serotonin, tyramine, dopamine, and agmatine. It was determined that nanoemulsion application had generally suppressive effect on the formation of BAs during storage. It was also found that especially orange and lemon nanoemulsion groups were effective on histamine formation. Histamine values ranged from 0.00 to 4.08 in all groups during storage and the levels were below the limit values of FDA and EU throughout the storage period for all treatment groups. Similarly, Quality Index (QI) values of BAs were found to be below legal limits in all groups. Consequently, it was found that nanoemulsions prepared from essential oils kept the BA formation at a lower level during storage.