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- Identification of leaf volatiles from olive (Olea europaea) and their possible role in the ovipositional preferences of olive fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae)Publication . Malheiro, Ricardo; Casal, Susana; Cunha, Sara C.; Baptista, Paula; Pereira, J.A.The olive fly, Bactrocera oleae (Rossi), is a monophagous pest that displays an oviposition preference among cultivars of olive (Olea europaea L.). To clarify the oviposition preference, the olive leaf volatiles of three olive cultivars (Cobrançosa, Madural and Verdeal Transmontana) were assessed by headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) at six different periods of olive fruit maturation and degrees of infestation. A total of 39 volatiles were identified, mainly esters and alcohols, with a minor percentage of aldehydes, ketones and terpenic compounds, including sesquiterpenes. At sampling dates with higher degrees of infestation, cv. Cobrançosa had, simultaneously, significantly lower infestation degrees and higher volatile amounts than the other two cultivars, with a probable deterrent effect for oviposition. The green leaf volatiles (GLVs) (Z)-3-hexen-1-ol and (Z)-3-hexen-1-ol acetate) were the main compounds identified in all cultivars, together with toluene. The abundance of GLVs decreas ed significantly throughout maturation, without significant differences among cultivars, while toluene showed a general increase and positive correlation with olive fly infestation levels. The results obtained could broaden our understanding of the roles of various types and amounts of olive volatiles in the environment, especially in olive fly host selection and cultivar preference.
- Chemometric classification of several olive cultivars from Trás-os-Montes region (Northeast of Portugal) using artificial neural networksPublication . Peres, António M.; Baptista, Paula; Malheiro, Ricardo; Dias, L.G.; Bento, Albino; Pereira, J.A.This work aimed to use artificial neural networks for fruit classification according to olive cultivar, as a tool to guarantee varietal authenticity. So, 70 samples, each one containing, in general, 40 olives, belonging to the six most representative olive cultivars of Trás-os-Montes region (Cobrançosa, Cordovil, Madural, Negrinha de Freixo, Santulhana and Verdeal Transmontana) were collected in different groves and during four crop years. Five quantitative morphological parameters were evaluated for each fruit and endocarp, respectively. In total, ten biometrical parameters were used together with a multilayer perceptron artificial neural network allowing the implementation of a classification model. Its performance was compared with that obtained using linear discriminant analysis. The best results were obtained using artificial neural networks. In fact, the external validation procedure for linear discriminant analysis, using olive data from olive trees not included in the model development, showed an overall sensibility and specificity in the order of 70% and varying between 45 and 97% for the individual cultivars. On the other hand, the artificial neural network model was able to correctly classify the same unknown olives with a global sensibility and specificity around 75%, varying from 58 and 95% for each cultivar. The predictive results of the artificial neural network model selected was further confirmed since, in general, it correctly or incorrectly classified the unknown olive fruits in each one of the six cultivars studied with, respectively, higher and lower probabilities than those that could be expected by chance. The satisfactory results achieved, even when compared with previous published works, regarding olive cultivar's classification, show that the neural networks could be used by olive oil producers as a preventive and effective tool for avoiding adulterations of Protected Designation of Origin or monovarietal olive oils with olives of non-allowed cultivars.
- Pão de centeio do olival: desenvolvimento do produto e sua caracterizaçãoPublication . Pawlak, Chalissa; Pereira, Ermelinda; Magalhães, Agostinho; Malheiro, Ricardo; Sarmento, Cleonice Mendes Pereira; Ferreira, Elisabete; Pereira, J.A.; Ramalhosa, ElsaO presente trabalho teve por objetivo desenvolver e caracterizar um novo produto, intitulado “Pão de Centeio do Olival”. A este pão de centeio foram adicionadas azeitonas verdes descaroçadas (conhecidas na região por “alcaparras”) e azeite. As “alcaparras” são processadas a partir de azeitonas verdes saudáveis, as quais são quebradas usando-se um martelo de madeira, sendo a polpa e o caroço separados. A polpa é colocada em água para remover o seu amargor e, em seguida, o produto é armazenado em solução salina até consumo. No presente trabalho procedeu-se à preparação de pães de centeio, seguindo a mesma formulação base, sem e com “alcaparras” (0 e 7%, respetivamente), e sem e com adição de azeite, os quais foram posteriormente armazenados a 25°C e analisados nos tempos de 0, 2 e 5 dias, quanto aos valores de pH, cinzas, gordura e teor de sal, bem como em termos microbiológicos (mesófilos, bolores e leveduras) e sensoriais. Todos os pães apresentaram valores de pH entre 5,87-6,02, de sal entre 1,30-1,84% (p.f.) e de cinzas 1,33-2,21% (p.f.). Os pães com "alcaparras" apresentaram o menor valor de pH e os maiores teores de sal e cinzas. Em relação à gordura, menores percentagens foram determinadas nos pães sem azeite face aos com azeite (1,38-2,88% (p.f.) versus 12,51-13,97% (p.f.)). Os mesófilos, variaram entre 0,8-7,1 log UFC/g (p.f.) e os bolores e leveduras entre 0,0-3,5 log UFC/g (p.f.), tendo os maiores valores sido obtidos no final do armazenamento (5 dias). Em termos sensoriais, o “Pão de Centeio do Olival” com 7% de “alcaparras” e azeite apresentou boa aceitação por parte de um grupo de consumidores. Em conclusão, o “Pão de Centeio do Olival” (com "alcaparras" e azeite) é um produto promissor para ser vendido em lojas gourmet.
- Microwave heating: a time saving technology or a way to induce vegetable oils oxidation?Publication . Malheiro, Ricardo; Casal, Susana; Ramalhosa, Elsa; Pereira, J.A.Microwave heating features modern lifestyle. The use of this technology enables a significant reduction in the time dedicated to prepare meals and opens new perspectives at the industrial level. In this chapter we report the combined effect of time/applied potency of microwave heating in comparison to conventional electric oven on the quality of vegetable oils. In general, the degradation pattern of vegetable oils under microwave heating was similar to that expected from other conventional heating methods, including oxidation, hydrolysis and polymerization. Nevertheless, microwave heating induced higher degradation extent, as confirmed by the physical and chemical evaluations reported, reducing the nutritional value of lipids. The combination of temperature and energy effects induced by microwaves, which could have strengthened the heating effect might lead to zonal overheating in the oils, a situation that deserves technological improvement. Nevertheless, most of the published studies compared high exposure times and temperatures, unusual on microwave domestic procedures, except for microwave frying. Therefore, the vegetable oils behavior under real cooking practices, power settings, and combined interaction of different ingredients, needs to be further exploit in order to provide concise information from nutritional, technological and health points of view. Based on these prospects and scientific findings the use of microwave is not discouraged, but vegetable oils heating should be reduced to the minimum, in order to reduce the degradation extent of important compounds, as lipossoluble vitamins, essential fatty acids, and phenolics, while reducing the formation of potentially hazard components, the oxidized lipids.
- Pão transmontano: the use of physicochemical characterization and chemometrics in order to achieve the PGI certificationPublication . Magalhães, Agostinho; Pereira, Ermelinda; Pawlak, Chalissa; Malheiro, Ricardo; Ferreira, Elisabete; Pereira, J.A.; Ramalhosa, ElsaThe purpose of the present work was to perform the physicochemical characterization and chemometrics of a traditional Portuguese bread, called “Pão do Nordeste Transmontano”, towards PGI certification application.
- Homeopathic drugs to control red rot disease in sisal plantsPublication . Gama, Erasto V.S.; Silva, Franceli; Santos, Ivanete; Malheiro, Ricardo; Soares, Ana Cristina Fermino; Pereira, J.A.; Armond, CintiaSisal—Agave sisalana Perrine ex. Engelm—is a key economical and social crop in the semi-arid region of Brazil, especially in the Bahia state. Sisal is severely affected by Aspergillus niger Thieg, the causal agent of sisal red rot. Currently, existing control strategies are fruitless. Here, we tested different homeopathic drugs Carbo vegetabilis, Ferrum metallicum, Natrum muriaticum, phosphorus and sulphur at centesimal Hahnemannian (CH) dynamizations, of 3CH, 5CH, 7CH, 9CH and 12CH, on Aspergillus niger. We measured in vitro growth inhibition, sporulation and germination of Aspergillus niger during 12 days. We assessed in planta Aspergillus niger incidence and disease severity. Our results show that homeopathic drugs inhibited Aspergillus niger growth in vitro, in a dynamization-dependent way. Natrum muriaticum 5CH revealed the higher inhibition of 66 %, whereas sulphur 5CH yielded the lowest inhibition of 6.4 %. Spore production was stimulated using all homeopathic drugs at all dynamization levels, whereas spore germination was reduced. In planta assays revealed different results from in vitro assays, corroborating that in planta and in vitro effectiveness is different according to the homeopathic drugs applied. Here, disease incidence was not reduced significantly, but disease severity was lower in treated plants, of 27.8 % using Ferrum metallicum 9CH than in control trials, of 73.6 %. Overall, our findings suggest that homeopathic drugs could be a good strategy to control Aspergillus niger incidence in sisal plants.
- Cooking impact in color, pigments and volatile composition of grapevine leaves (Vitis vinifera L. var. Malvasia Fina and Touriga Franca)Publication . Lima, Adriano Freitas; Pereira, J.A.; Baraldi, Ilton J.; Malheiro, RicardoGrapevine leaves (Vitis vinifera L. var. Malvasia Fina and Touriga Franca) under culinary treatment (blanching and boiling at 60, 75 and 90 min) were studied for their color, pigments and volatile fraction changes. Blanching and boiling caused a decrease in luminosity and a loss of green coloration in both varieties, while a yellow-brownish color arose. Significant correlations were established between the loss of green color (monochromatic variable a ∗ ) and the total chlorophylls content. The main volatiles in fresh leaves [(Z)-3-hexenal, (Z)-3-hexen-1-ol, and (Z)-3-hexenyl acetate] were drastically reduced by blanching and suppressed by boiling. Other compounds like pentanal and 6-methyl-5-hepten-2 one arose from blanching and boiling. A boiling time of 60 min is adequate for the culinary process of grapevine leaves, since the product is considered edible and the pigments and volatile changes are not as drastic as observed at 75 and 90 min of boiling.
- Actividade antioxidante de azeitonas verdes descaroçadas produzidas em Trás-os-Montes: estudo do efeito da cultivar.Publication . Malheiro, Ricardo; Sousa, Anabela; Casal, Susana; Bento, Albino; Pereira, J.A.A azeitona de mesa e parte integrante da dieta Mediterrânica, sendo considerada uma fonte importante de antioxidantes. Em Trás-os-Montes, no inicio do Outono, são processadas de forma artesanal um tipo de azeitona de mesa denominada "alcaparras". Para 0 seu processamento, os frutos são colhidos verdes, partidos, retirado o caroço e introduzidos em agua, mudada diariamente, durante aproximadamente uma semana ate que possam ser consumidos. De uma maneira geral, o factor cultivar não e tido em conta no processamento, apesar de apresentarem composição química e propriedades tecnológicas distintas. Assim, com o presente trabalho pretendeu-se estudar 0 efeito da cultivar na actividade antioxidante das "alcaparras". Neste sentido, foram processados lotes de azeitonas verdes descaroçadas monovarietais, à escala laboratorial das cultivares Cobrançosa, Madura!, Negrinha de Freixo, Santulhana e Verdeal Transmontana.
- Effect of different attractants used in Olipe traps for olive fly mass-trapping on parasitoids in the Northeast of Portugal.Publication . Sousa, Anabela; Malheiro, Ricardo; Rodrigues, S.; Casal, Susana; Bento, Albino; Rodrigues, S.The hymenoptera parasitoids represent and important beneficial group in olive agroecosystem. Their action maintains certain olive pest species numbers lower than the economic threshold. In this can text, to improve their activity and increase the sustainability of the olive agroecosystem it is necessary to know the negative effect of different agronomic practices in their populations. In ecological production, mass-trapping is an important control method against the olive fruit fly, Bactrocera oleae Gmel., the most serious pest of olives in the Mediterranean countries. The aim of the present work was to study the effect on parasitoids of different attractants used combined with Olipe traps.
- Borage, calendula, cosmos, Johnny Jump up, and pansy flowers: volatiles, bioactive compounds, and sensory perceptionPublication . Fernandes, Luana; Casal, Susana; Pereira, J.A.; Malheiro, Ricardo; Rodrigues, Nuno; Saraiva, Jorge A.; Ramalhosa, ElsaThe aim of the present work was to study the main volatile and bioactive compounds (monomeric anthocyanins, hydrolysable tannins, total flavonoids, and total reducing capacity) of five edible flowers: borage (Borage officinalis), calendula (Calendula arvensis), cosmos (Cosmos bipinnatus), Johnny Jump up (Viola tricolor), and pansies (Violaxwittrockiana), together with their sensory attributes. The sensory analysis (10 panelists) indicated different floral, fruity, and herbal odors and taste. From a total of 117 volatile compounds (SPME-GC-MS), esters were most abundant in borage, sesquiterpenes in calendula, and terpenes in cosmos, Johnny Jump up, and pansies. Some bioactive and volatile compounds influence the sensory perception. For example, the highest content of total monomeric anthocyanins (cosmos and pansies) was associated with the highest scores of colors intensity, while the floral and green fragrances detected in borage may be due to the presence of ethyl octanoate and 1-hexanol. Therefore, the presence of some volatiles and bioactive compounds affects the sensory perception of the flowers.