Chromatographic determination of fatty acids profiles in regionally-produced Portuguese goat cheese along curing

The biochemistry of cheese ripening involves mechanisms such as glycolysis, proteolysis and lipolysis. Fatty acids are released by the action of lipases from different sources, milk, rennet, bacteria, moulds included as secondary starters, and other exogenous lipases, during lipolysis [1]. The composition of the lipid fraction contributes positively to the flavour of cheese, for being precursors of more complex aroma compounds responsible for the characteristic “goaty flavour” of goat cheeses [2]. Goat milk is recognized by its easier digestibility, alkalinity, buffering capacity and certain therapeutic values in medicine and human nutrition [3]. A high total content of fatty acids is strongly linked to a rancid and tart off flavour in goat milk and may be considered undesirable in most cheese varieties [4]. In this sense, the purpose of the present study was to examine the composition and changes in fatty acids and saponification value of goat cheese during curing period (2, 7 and 12 months). Goat cheese was made in industrial unit of Cachão - Mirandela (Trás-os- Montes) with raw milk Serrana goats’ race, salt and rennet from animal origin. During the first two months, the samples were stored in a ripening chamber (9.5-11 °C and RH 75-85%). From the second month to one year, the samples were stored in a preservation chamber (10.5-12 °C and RH 75-85%). The fatty acids profile of the inner part of the cheese was analyzed by gas-chromatography coupled to flame ionization detection (GC-FID). The degree of saponification was determined both in the crust and inside the cheese by HCl titration of ethanol KOH solution of the samples. Twenty-six fatty acids (FA) were identified and quantified in the inner part of the cheese (total fat was 45-46 g/100 g during the curing period). Saturated fatty acids (SFA) did not change up to 7 months of curing, increasing only after 12 months, being palmitic (C16:0), stearic (C18:0), myristic (C14:0) and capric (C10:0) acids the most abundant FA in this class. Monounsaturated fatty acids (MUFA) decreased only after 12 months, and oleic acid (C18:1) was the predominant FA. In polyunsaturated fatty acids (PUFA) class, the most abundant were linoleic (C18:2) and linolenic (C18:3) acids, and followed the same tendency of MUFA. This is corroborated by an increase in the degree of saponification, either in the crust as in the inner part of the cheese, after 12 months of curing, probably related with the saturation of the fatty acids [3]. Extra-long curing can be done in cheeses produced with goat milk up to seven months of storage without changing the total fat and individual FA content.

Coerced Mechanical Coarsening of Nanoparticle Assemblies

Coarsening is a ubiquitous phenomenon [1-3] that underpins countless processes in nature, including epitaxial growth [1,3,4], the phase separation of alloys, polymers and binary fluids [2], the growth of bubbles in foams5, and pattern formation in biomembranes6. Here we show, in the first real-time experimental study of the evolution of an adsorbed colloidal nanoparticle array, that tapping-mode atomic force microscopy (TM-AFM) can drive the coarsening of Au nanoparticle assemblies on silicon surfaces. Although the growth exponent has a strong dependence on the initial sample morphology, our observations are largely consistent with modified Ostwald ripening processes [7-9]. To date, ripening processes have been exclusively considered to be thermally activated, but we show that nanoparticle assemblies can be mechanically coerced towards equilibrium, representing a new approach to directed coarsening. This strategy enables precise control over the evolution of micro- and nanostructures.

Chestnut and lemon balm based ingredients as natural preserving agents of the nutritional profile in matured “Serra da Estrela” cheese

Chestnut flowers, lemon balm plants and their decoctions were incorporated into "Serra da Estrela" cheese, to assess their potential to preserve its nutritional properties and provide new foodstuffs. The analyses were carried out after the normal ripening period of 1month and after 6months of storage. The most abundant nutrients were proteins and fats. The most abundant minerals were Ca and Na, while C16:0 and C18:1 were the main fatty acids. Saturated fatty acids were the most abundant, followed by the monounsaturated. Moisture seemed to be lower in the samples with the plants incorporated. The dried plants, when incorporated, seemed to be more efficient as preservers then the decoctions, although these better preserved the proteins. These plants can be regarded as promising natural preservers in foodstuffs cheese, given the preservation of key parameters and the slight impact on the nutritional value.

Evolution of factors affecting mechanical olive harvesting

Harvest efficiency is defined as the percentage of fruits harvested by total production. The percentage of fruits harvested is less than 100% when working with trunk shakers to detach olives. It is important to increase the percentage of fruits harvested in order to increase farmer’s income. This objective can be achieved knowing the evolution of the main factors affecting fruit detachment. Fruit removal force (FRF), fruit weight (P) and the ratio between them are important for harvest efficiency. Field trials took place for two years (2013-2014) in Vilariça Valley, northeast Portugal in an olive orchard with ‘Cobrançosa Transmontana’ cultivar. It was adopted a mechanical harvesting system based on a trunk shaker to detach fruits, and an inverted umbrella to collect fruits. Elementary operation times were measured in seconds to evaluate work rates. FRF and P were measured in the ripening period, to evaluate their evolution. In this paper are presented the preliminary results of the ratio FRF (fruit removal force)/fruit weight evolution during the ripening period (P) and the results of the equipment work rate (trees h-1). The ratio FRF/P has predominantly descendant values in the weeks before harvest, from 140 to 80 as a result of a FRF downward variation from 4.9 to 2.94 N and an upward variation of P from 0.0294 to 0.0637 N. The FRF/P ratio stabilizes the decline in the last week of November just before harvesting, registering in some cases a slight increase in consequence of FRF increase higher than P increase (contrary to the tendency of previous weeks). Equipment work rate showed values between 40 and 57 trees h-1, confirming previous results.

Unravelling the nanostructure of strawberry fruit pectins by atomic force microscopy

Atomic force microscopy (AFM) allows the analysis of individual polymers at nanostructural level with a minimal sample preparation. This technique has been used to analyse the pectin disassembly process during the ripening and postharvest storage of several fleshy fruits. In general, pectins analysed by AFM are usually visualized as isolated chains, unbranched or with a low number of branchs and, occasionally, as large aggregates. However, the exact nature of these structures is unknown. It has been suggested that pectin aggregates represent a mixture of rhamnonogalacturonan I and homogalacturonan, while isolated chains and their branches are mainly composed by polygalacturonic acid. In order to gain insight into the nature of these structures, sodium carbonate soluble pectins from ripe strawberry (Fragaria x ananassa, Duch.) fruits were subjected to enzymatic digestion with endo-Polygalacturonase M2 from Aspergillus aculeatus, and the samples visualized by AFM at different time intervals. Pectins isolated from control, non-transformed plants, and two transgenic genotypes with low level of expression of ripening-induced pectinase genes encoding a polygalacturonase (APG) or a pectate lyase (APEL) were also included in this study. Before digestion, isolated pectin chains from control were shorter than those from transgenic fruits, showing number-average (LN) contour length values of 73.2 nm vs. 95.9 nm and 91.4 nm in APG and APEL, respectively. The percentage of branched polymers was significantly higher in APG polyuronides than in the remaining genotypes, 33% in APG vs. 6% in control and APEL. As a result of the endo-PG treatment, a gradual decrease in the main backbone length of isolated chains was observed in the three samples. The minimum LN value was reached after 8 h of digestion, being similar in the three genotypes, 22 nm. By contrast, the branches were not visible after 1.5-2 h of digestion. LN values were plotted against digestion time and the data fitted to a first-order exponential decay curve, obtaining R2 values higher than 0.9. The half digestion time calculated with these equations were similar for control and APG pectins, 1.7 h, but significantly higher in APEL, 2.5 h, indicating that these polymer chains were more resistant to endo-PG digestion. Regarding the pectin aggregates, their volumes were estimated and used to calculate LN molecular weights. Before digestion, control and APEL samples showed complexes of similar molecular weights, 1722 kDa, and slightly higher than those observed in APG samples. After endo-PG digestion, size of complexes diminished significantly, reaching similar values in the three pectin samples, around 650 kDa. These results suggest that isolated polymer chains visualized by AFM are formed by a HG domain linked to a shorter polymer resistant to endo-PG digestion, maybe xylogalacturonan or RG-I. The silencing of the pectate lyase gene slightly modified the structure and/or chemical composition of polymer chains making these polyuronides more resistant to enzymatic degradation. Similarly, polygalacturonic acid is one of the main component of the aggregates.

Estudio de factibilidad técnico económico para la sostenibilidad de fincas diversificadas administradas por los excombatientes del FMLN en el cantón Santa Isabel del municipio de Guazapa, departamento de San Salvador.

En el Cantón Santa Isabel del Municipio de Guazapa, se ha implementado un proyecto de fincas diversificadas de ocho tipos de cultivo de frutas, siendo éstas la papaya, el jocote, la anona, limón pérsico, zapote, naranja, mango y níspero. Dicho proyecto está siendo administrado por los ex combatientes del FMLN, que obtuvieron propiedades a través del programa de transferencia de tierras quienes además fueron beneficiados por el Convenio celebrado entre El Salvador y el Reino de Bélgica, garantizándole la asistencia técnica y financiera al proyecto. Este informe pretende aportar criterios que faciliten la toma de decisiones a los propietarios de fincas diversificadas para darle el mantenimiento y desarrollo a dicho proyecto. A través de la investigación realizada se determinó que, no existe un marco teórico básico sobre la implementación de un modelo de fincas diversificadas de frutas, sin embargo ha generado expectativas para los propietarios de las fincas que dicho proyecto pueda ser rentable a corto y mediano plazo y autosostenible a largo plazo. Para el desarrollo de la investigación del proyecto denominado “Estudio de factibilidad Técnico-económico para la sostenibilidad de fincas diversificadas administradas por los ex combatientes del FMLN en el Cantón Santa Isabel del Municipio de Guazapa en el Departamento de San Salvador” fue necesario el diseño de encuestas y entrevistas dirigidas a los propietarios de fincas, al agrónomo encargado del proyecto y al asesor técnico. Así como también a los comerciantes y distribuidores de frutas de los diferentes mercados municipales. Obteniendo datos e información relevante para el desarrollo de la propuesta de este estudio se extrae los resultados que muestran la demanda que tendrán las frutas cultivadas en el proyecto así como también la oferta, el precio y la forma de comercialización que se da en el mercado. Se determinó que el proyecto de fincas diversificadas puede ser rentable y autosostenible si se cultivan dos manzanas de terreno con una distribución adecuada de los cultivos, los ingresos que se obtendrán a corto plazo ayudarán al funcionamiento de las fincas, a mediano plazo ayudarán al desarrollo del proyecto y los de largo plazo servirán para hacerlas autosostenibles, cabe mencionar que es necesario hacer uso de un financiamiento para impulsar el desarrollo de las fincas, además el proyecto fue evaluado con los métodos más conocidos para determinar si dicho proyecto es rentable, autosostenible y logrará mejorar la calidad de vida de los propietarios de fincas diversificadas y sus familias. Debido a que el proyecto tendrá un Valor Actual Neto de $ 35,412.76 en el año 9 y la recuperación de la inversión se obtendrá a partir del año 4, además la relación Beneficio/Costo es de $0.08.

A possibility for non-invasive diagnosis of superficial scald in 'Rocha' pear based on chlorophyll a fluorescence, colorimetry, and the relation between alpha-farnesene and conjugated trienols

This study aimed to identify physiological markers in superficially scalded 'Rocha' pear (Pyrus communis L 'Rocha') that would relate to chlorophyll a fluorescence (CF), allowing a non-invasive diagnosis of the disorder. Conditions chosen before shelf life provided two fruit groups with different developing patterns and severity of superficial scald: T fruit fully developed the disorder in storage, while C fruit developed it progressively throughout shelf life. Principal component analysis (PCA) of all the measured variables, and simple linear correlations among several major parameters and scald index (SI)/shelf life showed that scald and ripening/aging were concurring processes, and that it was not possible to isolate a particular variable that could deliver a direct non-invasive diagnosis of the disorder. For both fruit groups the SI resulted from the balance between the reducing power (OD200) and the content of conjugated trienols (CTos) and alpha-farnesene (alpha-Farn) in the fruit peel. At OD200 > 150 there was a linear relationship between CTos and OD200, suggesting that the level of antioxidants was self-adjusted in order to compensate the CTos level. However, at OD200 < 150 this relationship disappeared. A consistent linear relationship between dos and alpha-Farn existed throughout shelf life in both fruit groups, contrarily to the early storage stage, when those compounds do not relate linearly. The CF variables F-0, F-v/F-m, and the colorimetric variables, L* and h degrees were used in multi-linear regressions with other physiological variables. The regressions were made on one of the fruit groups and validated through the other. Reliable regressions to alpha-Farn and CTos were obtained (R approximate to 0.6; rmsec approximate to rmsep). Our results suggest that a model based on CF and colorimetric parameters could be used to diagnose non-invasively both the contents and the relationship between alpha-Farn and CTos and hence the stage of scald development. (C) 2011 Elsevier By. All rights reserved.

Biodiesel production from Jathropha curcas l. oil using chemical or enzymatic catalysts

Doutoramento em Engenharia dos Biossistemas - Instituto Superior de Agronomia - UL

Influence of enzymes and technology on the composition of Cobrançosa and Galega vulgar virgin olive oils

Doutoramento em Engenharia Alimentar - Instituto Superior de Agronomia - UL

Effects of different intensity of early leaf removal on vegetative and productive activity and grape quality (cv. Nero d'Avola, Vitis vinifera)

Mestrado Vinifera Euromaster - Instituto Superior de Agronomia - UL

Influence of leaf removal on berry thermal efficiency for anthocyanin accumulation

The aim of this work was to analyse the effects of leaf removal on Touriga Nacional berry temperature and consequent thermal efficiency for anthocyanins biosynthesis. The field experiment was located at Dão Wine Research Station, Nelas, Portugal in an adult vineyard planted with North-South oriented rows, with the red grape variety Touriga Nacional grafted on 110R rootstock. The vines were trained on a vertical shoot positioning, spur-pruned on a bilateral Royat cordon system and deficit irrigated (50% ETc). The experimental design was a randomized complete block design with four replications of twelve vines per elemental plot, and the following two treatments: basal leaf removal (LR) and a control non-defoliated (ND). Berry temperature (Tb) was measured continuously during the second half (3rd to 19th September) of the 2009 ripening period using two-junction, fine-wires copper-constantan thermocouples manually inserted into the berries and connected to a data logger. A sample of clusters located in different canopy positions (exposed and internal; facing East and West) of 4 vines per treatment were used. To quantify the effect of Tb on anthocyanins biosynthesis, the berry hourly mean temperatures were converted into normal heat hours (NHH) and accumulated per day (NHHd) and per monitoring period (NHHc). For quantification of thermal requirements for anthocyanins synthesis and accumulation, a minimum of 10°C, a maximum of 35°C, and an optimum of 26°C were used. Meteorological variables were measured at an automatic weather station installed within the experimental plot. For all days of the monitoring period, daily average berry temperature (dTb) of all monitored berries was lower in ND treatment than in LR, being the maximum differences between treatments registered on 11th September. The highest dTb differences between treatments were registered on the clusters located at the west side of the canopy on 7th September while dTb of the clusters located in the centre of the canopy was less affected by leaf removal. The control non-defoliated treatment (ND) presented a significantly higher NHHc than that of LR being the higher differences presented by the clusters located in the west side. The lowest differences in NHHc were obtained in the clusters located in the centre of the canopy. Our results show that the thermal efficiency for berry anthocyanins accumulation was significantly affected by leaf removal and that this effect was dependent of the meteorological conditions, time of the day and berry/cluster location into the vine canopy.

Assessing canopy temperature patterns in two grapevine varieties subjected to deficit irrigation: a tool to optimize water management ?

A better understanding of grapevine responses to drought and high air temperatures can help to optimize vineyard management to improve water use efficiency, yield and berry quality. Faster and robust field phenotyping tools are needed in modern precision viticulture, in particular in dry and hot regions such as the Mediterranean. Canopy temperature (Tc) is commonly used to monitor water stress in plants/crops and to characterize stomatal physiology in different woody species including Vitis vinifera. Thermography permits remote determination of leaf surface or canopy temperature in the field and also to assess the range and spatial distribution of temperature from different parts of the canopies. Our hypothesis is that grapevine genotypes may show different Tc patterns along the day due to different stomatal behaviour and heat dissipation strategies. We have monitored the diurnal and seasonal course of Tc in two grapevine genotypes, Aragonez (syn. Tempranillo) and Touriga Nacional subjected to deficit irrigation under typical Mediterranean climate conditions. Temperature measurements were complemented by determination of the diurnal course of leaf water potential (ψleaf) and leaf gas exchange. Measurements were done in two seasons (2013 and 2014) at different phenological stages: i) mid-June (green berry stage), ii) mid-July (veraison), iii) early August (early ripening) and iv) before harvest (late ripening). Correlations between Tc and minimal stomatal conductance will be presented for the two genotypes along the day. Results are discussed over the use of thermal imagery to derive information on genotype physiology in response to changing environmental conditions and to mild water stress induced by deficit irrigation. Strategies to optimize the use of thermal imaging in field conditions are also proposed

Canopy management effects on Syrah grapevines under tropical semi-arid conditions.

The aim of this study was to evaluate the effects of shoot topping and leaf removal practices on vegetative vigor, yield and physicochemical characteristics of the 'Syrah' grape in the semi-arid tropical climate conditions of the São Francisco River Valley in the northeast of Brazil. The experiment was conducted over five growing cycles from 2010 to 2012 in a 'Syrah' commercial vineyard in the municipality of Casa Nova, Bahia, Brazil. Treatments consisted of leaf removal once or twice during fruit set or at the beginning of bunch closure, and one or two shoot toppings of the berry when pea-sized or 10 days after berry growth had commenced. Leaf removal and shoot topping did not affect yield, plant vigor components nor the main attributes of fruit quality. In contrast, there was a seasonal effect with higher yield and better balance between production and vigor in grapes produced in the first half of 2012. The Syrah grape quality was favored in cycles in the first half of the year when its ripening phase coincided with the period of mild temperatures.

A possibility for non-invasive diagnosis of superficial scald in 'Rocha' pear based on chlorophyll a fluorescence, colorimetry, and the relation between alpha-farnesene and conjugated trienols

This study aimed to identify physiological markers in superficially scalded 'Rocha' pear (Pyrus communis L 'Rocha') that would relate to chlorophyll a fluorescence (CF), allowing a non-invasive diagnosis of the disorder. Conditions chosen before shelf life provided two fruit groups with different developing patterns and severity of superficial scald: T fruit fully developed the disorder in storage, while C fruit developed it progressively throughout shelf life. Principal component analysis (PCA) of all the measured variables, and simple linear correlations among several major parameters and scald index (SI)/shelf life showed that scald and ripening/aging were concurring processes, and that it was not possible to isolate a particular variable that could deliver a direct non-invasive diagnosis of the disorder. For both fruit groups the SI resulted from the balance between the reducing power (OD200) and the content of conjugated trienols (CTos) and alpha-farnesene (alpha-Farn) in the fruit peel. At OD200 > 150 there was a linear relationship between CTos and OD200, suggesting that the level of antioxidants was self-adjusted in order to compensate the CTos level. However, at OD200 < 150 this relationship disappeared. A consistent linear relationship between dos and alpha-Farn existed throughout shelf life in both fruit groups, contrarily to the early storage stage, when those compounds do not relate linearly. The CF variables F-0, F-v/F-m, and the colorimetric variables, L* and h degrees were used in multi-linear regressions with other physiological variables. The regressions were made on one of the fruit groups and validated through the other. Reliable regressions to alpha-Farn and CTos were obtained (R approximate to 0.6; rmsec approximate to rmsep). Our results suggest that a model based on CF and colorimetric parameters could be used to diagnose non-invasively both the contents and the relationship between alpha-Farn and CTos and hence the stage of scald development. (C) 2011 Elsevier By. All rights reserved.

Natural parasitism of lepidopteran eggs by Trichogramma species (Hymenoptera: Trichogrammatidae) in agricultural crops in Minas Gerais, Brazil.

The genus Trichogramma Westwood (Hymenoptera: Trichogrammatidae) includes insect egg parasitoids that are widely used throughout the world as control agents of pest insects. The aim of this study was to identify the species of Trichogramma naturally associated with the eggs of lepidopteran pests of the following agricultural and horticultural crops: collards, Brassica oleracea L. (Brassicales: Brassicaceae); papaya, Carica papaya L. (Capparales: Caricaceae); tomato, Lycopersicon esculentum Mill. (Solanales: Solanaceae); cassava, Manihot esculenta Crantz (Malpighiales: Euphorbiaceae); banana, Musa sp. L. (Zingiberales: Musaceae); passion fruit, Passiflora sp. Degener (Malpighiales: Passifloraceae); sugarcane, Saccharum sp. L. (Poales: Poaceae); and corn (maize), Zea mays L. (Poales: Poaceae); and an invasive species (Sodom?s apple milkweed, Calotropis procera Aiton; Gentianales: Apocynaceae) in the semiarid region of Minas Gerais, Brazil. We report natural parasitism by Trichogramma in eggs of Agraulis vanillae vanillae (L.) (Lepidoptera: Nymphalidae), Antichloris eriphia F. (Lepidoptera: Arctiidae), Danaus sp. (L.) (Lepidoptera: Nymphalidae), Diatraea saccharalis F. (Lepidoptera: Crambidae), Erinnyis ello L. (Lepidopera: Sphingidae), and Protambulyx strigilis L. (Lepidopera: Sphingidae). In total, 2,242 specimens of Trichogramma were obtained, belonging to the species T. pretiosum Riley, T. manicobai Brun, Moraes & Soares, T. marandobai Brun, Moraes & Soares, and T. galloi Zucchi. These species of Trichogramma may be candidates for biological control programs of lepidopteran pests in the semiarid region of Minas Gerais and in other semiarid regions.