Paula Correia

Chemical profiling of Portuguese Pinus pinea L. nuts

BACKGROUND The first detailed chemical characterisation of Portuguese pine nut (Pinus pinea L.) is reported concerning proximate composition, fatty acid, mineral and vitamin contents. RESULTS Based on the analysis of 27 different populations, pine nuts were characterised by high contents of fat (47.7 g per 100 g dry matter (DM)), protein (33.8 g per 100 g DM) and phosphorus (1130 mg per 100 g DM) and low contents of moisture (5.9 g per 100 g DM) and starch (3.5 g per 100 g DM). They were also found to be a good source of zinc, iron and manganese. CONCLUSION Mineral composition seemed to be most prone to variation, suggesting its potentially useful role in discriminating Mediterranean pine nuts. A significant variability was found in the nut composition of Portuguese P. pinea populations.

Analysis of the physical-chemical and sensorial properties of Maria type cookies

Abstract Given the importance of the cookies of type Maria worldwide, and considering the absence of any scientific study setting out their main features, it becomes important to identify the differentiating characteristics of several commercialized brands, in particular related to the chemical, physical and sensory characteristics. In this way, the aim of this work was to study and compare eight different brands of cookies of type Maria. The elemental chemical analysis (moisture, ash, protein, fat, fibre and carbohydrates contents), determination of physical parameters (volume, density, texture and colour) and sensory evaluation of studied cookies were performed. Multivariate statistical methods (Pearson correlation, principal component analysis and cluster analysis) were applied to estimating relationships in analysed data. The results for the elemental analysis showed that the samples were very similar in terms of some components, like for example ashes, while quite different in terms of other components, such as moisture and fat contents. With respect to texture and colour the samples showed, in general, some important differences. In terms of sensory evaluation, the sample C was the one that in most sensory tests gathered the preference of the panellists. The cluster analysis showed that the sample A was much different from the other samples. The results of principal component analysis showed that the main component explains 32.6 % of the total variance, and is strongly related to variables associated to colour.

Effect of drying temperatures on starch-related functional and thermal properties of acorn flours.

The application of starchy flours from different origins in food systems depends greatly on information about the chemical and functional properties of such food materials. Acorns are important forestry resources in the central and southern regions of Portugal. To preserve these fruits and to optimize their use, techniques like drying are needed. The effects of different drying temperatures on starch-related functional properties of acorn flours obtained from dried fruits of Quercus rotundifolia (QR) and Quercus suber (QS) were evaluated. Flours were characterized for amylose and resistant starch (RS) contents, swelling ability, and gelatinization properties. Drying temperature mainly affected amylose content and viscoamylographic properties. Amylograms of flours from fruits dried at 60 °C displayed higher consistency (2102 B.U. and 1560 B.U., respectively, for QR and QS). The transition temperatures and enthalpy were less affected by drying temperature, suggesting few modifications in starch structure during drying. QR flours presented different functional properties to those obtained from QS acorn flours. The effect of drying temperatures were more evident in QR.

Analysis of factors influencing the physical, chemical and sensorial properties of Serra da Estrela cheeses

The objective of this study was to evaluate the chemical, color, textural, and sensorial characteristics of Serra da Estrela cheese and also to identity the factors affecting these properties, namely thistle ecotype, place of production, dairy and maturation. The results demonstrated that the cheeses lost weight mostly during the first stage of maturation, which was negatively correlated with moisture content, being this also observed for fat and protein contents. During maturation the cheeses became darker and with a yellowish coloration. A strong correlation was found between ash and chlorides contents, being the last directly related to the added salt in the manufacturing process. The flesh firmness showed a strong positive correlation with the rind harness and the firmness of inner paste. Stickiness was strongly related with all the other textural properties being indicative of the creamy nature of the paste. Adhesiveness was positively correlated with moisture content and negatively correlated with maturation time. The trained panelists liked the cheeses, giving high overall assessment scores, but these were not significantly correlated with the physicochemical properties. The salt differences between cheeses were not evident for the panelists, which was corroborated by the absence of correlation between the perception of saltiness and the analyzed chlorides contents. The Factorial Analysis of the chemical and physical properties evidenced that they could be explained by two factors, one associated to the texture and the color and the other associated with the chemical properties. Finally, there was a clear influence of the thistle ecotype, place of production and dairy factors in the analyzed properties.

Knowledge about dietary fibre: a fibre study framework

Abstract The objective of this work was to study the degree of knowledge about dietary fibre (DF), as influenced by factors such as gender, level of education, living environment or country. For this, a descriptive cross-sectional study was undertaken on a non-probabilistic sample of 6010 participants from 10 countries in different continents (Europe, Africa and America). The results showed that the participants revealed on average a positive but still low global level of knowledge, which alerts for the need to take some actions to further inform the population about DF and its role as a component of a healthy diet. The results also indicated differences between genders, levels of education, living environments and countries. The highest level of knowledge was revealed by the participants from female gender, with higher education and living in urban areas. Concerning the country, the best informed were the participants from Romania, followed by those from Portugal and Turkey while the least informed were from Egypt.

Artificial neural network modelling of the chemical composition of carrots submitted to different pre-drying treatments

The effect of various pre-drying treatments on the quality of dried carrots was evaluated by assessing the values of moisture, ash, protein, fibre, sugars and colour. The pre-drying treatments under investigation were dipping, either in ascorbic acid or sodium metabisulphite at different concentrations and pre-treatment times, as well as blanching. The experimental data was analysed using neural networks, so that relevant patterns in the data were found and conclusions drawn about each variable. The results showed that the type of pre-drying treatment (chemical or physical) had variable impact on the nutritional composition of the dried carrots but not on the colour parameters, which were found to be mostly unaffected by the pre-treatment procedure. Pre-treatment with chemical agents such as ascorbic acid or metabisulphite seem to have the least impact on the parameters studied. The results of the analysis by artificial neural networks confirmed these findings.

Effect of different thistle flower ecotypes as milk-clotting in Serra da Estrela cheese

Purpose Thistle flower (Cynara cardunculus) aqueous extracts, as rich source of milk-clotting peptidases, have been widely used for cheeses marketed under the Registry of the Protected Designation of Origin, as it is the case of Serra da Estrela cheese, manufactured from raw ewes’ milk and without addition of any commercial starter culture. This paper aims at studying the influence of six different ecotypes of thistle flowers in cheese properties during the ripening and of final products. Design/methodology/approach Cheeses were produced with different thistle flower extracts and then the clotting time, weight and colour of cheeses, as well as texture properties and sensorial characteristics, were evaluated. Findings The clotting time varied from 47 to 66 min, and the weight loss along ripening varied between 32 and 40 per cent. There was some influence of thistle flower ecotype on the colour during ripening and in the final product. The results of texture analysis revealed significant differences between the thistle ecotypes: crust firmness varying from 2.4 to 5.6 N; inner firmness from 0.82 to 1.82 N; stickiness from −0.5 to −1.60 N; adhesiveness from −3.0 to −11.3 N.s; and Ecotype C was particularly distinguishable. Sensorial evaluation revealed differences among the cheeses, with Ecotype C receiving the highest score for global appreciation. Originality/value The usage of different extracts of thistle flower to produce Serra da Estrela cheese with different properties is a novelty, and it allows the possibility of manipulating this parameter in the future so as to produce cheeses with specific characteristics, addressed to different consumer targets.

Effect of Drying on Total Phenolic Compounds, Antioxidant Activity, and Kinetics Decay in Pears

The polyphenols have been identified as food components sensitive to high temperatures; therefore, the application of heat treatments can lead to a significant reduction in the phenolic content and also on antioxidant capacity. The objectives of the present work were to investigate the decrease in total phenolic compounds and antioxidant activity in pears during air drying at different temperatures and to model the kinetics of those variations. The pears (cv. D. Joaquina) were dried at 60°C and 70°C in an electrical drying chamber with hot air at 0.5 m/s. Along drying several samples were collected for analysis, being submitted to multiple extractions with methanol and acetone solutions. The phenolic compounds were determined by the Folin-Ciocalteu method and the antioxidant activity was determined by the ABTS method. The results showed that three successive extractions with methanol followed by three extractions with acetone solution was necessary for an efficient quantification of the total phenolic compounds and antioxidant activity. The decrease along drying was found to be of about 40% for both parameters and for the two temperatures studied. Furthermore, a relatively strong relation was observed between total phenols and antioxidant activity. The mathematical modeling of the kinetics showed that a 3-parameter exponential decay function was the best function to describe the experimental data, and the kinetic constants were found to vary in the range 0.0136–0.0444 min−1.

Benefits of dietary fibre to human health: study from a multi-country platform

Purpose Because dietary fibre has been recognized as a major ally to the maintenance of a healthy body as well as to help against the development of some chronic diseases, this paper aims to study the level of knowledge of a relatively wide range of people about the health effects related to the ingestion of dietary fibre in appropriate dosages. Design/methodology/approach A descriptive cross-sectional study was undertaken on a non-probabilistic sample of 6,010 participants. The data were collected from 10 countries in three different continents (Europe, Africa and America) and measured the level of knowledge regarding different health benefits from dietary fibre. The questionnaires were applied by direct interview after verbal informed consent. Findings The results obtained considering the general level of knowledge revealed a considerable degree of information about the benefits of fibre (average score of 3.54 ± 0.5, on a scale from 1 to 5). There were significant differences between genders (p < 0.001), with higher average score for women, and also for level of education (p < 0.001), with higher score for university level. The living environment also showed significant differences (p < 0.001), with people living in urban areas showing a higher degree of knowledge. Also for countries the differences were significant (p < 0.001), with the highest score obtained for Portugal (3.7), and the lowest for Croatia, Italy, Latvia, Macedonia and Romania (3.5). However, despite these differences, the results showed that for all the countries the degree of knowledge was good (above 3.5), corresponding to a minimum level of knowledge of 70 per cent. Originality/value This work is considered important due to the wide coverage, including so many countries inclusive with different social and cultural settings. The study allowed concluding that, in general, the participants in the study were quite well informed about the benefits of dietary fibre for the improvement of human health, regardless of gender, level of education, living environment or country. This finding is very relevant considering the diversity of people that composed the sample and reinforces the necessity of continuing with educational policies aimed at providing the general population with the knowledge that might help them make appropriate food choices.

Knowledge about sources of dietary fibres and health effects using a validated scale: a cross-country study

OBJECTIVES Dietary fibre (DF) is one of the components of diet that strongly contributes to health improvements, particularly on the gastrointestinal system. Hence, this work intended to evaluate the relations between some sociodemographic variables such as age, gender, level of education, living environment or country on the levels of knowledge about dietary fibre (KADF), its sources and its effects on human health, using a validated scale. STUDY DESIGN The present study was a cross-sectional study. METHODS A methodological study was conducted with 6010 participants, residing in 10 countries from different continents (Europe, America, Africa). The instrument was a questionnaire of self-response, aimed at collecting information on knowledge about food fibres. The instrument was used to validate a scale (KADF) which model was used in the present work to identify the best predictors of knowledge. The statistical tools used were as follows: basic descriptive statistics, decision trees, inferential analysis (t-test for independent samples with Levene test and one-way ANOVA with multiple comparisons post hoc tests). RESULTS The results showed that the best predictor for the three types of knowledge evaluated (about DF, about its sources and about its effects on human health) was always the country, meaning that the social, cultural and/or political conditions greatly determine the level of knowledge. On the other hand, the tests also showed that statistically significant differences were encountered regarding the three types of knowledge for all sociodemographic variables evaluated: age, gender, level of education, living environment and country. CONCLUSIONS The results showed that to improve the level of knowledge the actions planned should not be delineated in general as to reach all sectors of the populations, and that in addressing different people, different methodologies must be designed so as to provide an effective health education.