Daniela Costa

Evaluation of phenolic compounds and antioxidant activity of blueberries and modelization by artificial neural networks

ABSTRACT The study aimed at evaluating the influence of different production conditions, conservation, and extraction procedures on the total phenolic compounds and antioxidant activity of blueberries by DPPH and ABTS methods. The production factors considered were origin, altitude of the farm location, and age of the bushes. The conservation conditions considered were freezing as opposed to the fresh product. The extraction procedures included two different solvents and two orders of extraction. The data analysis was carried out by training artificial neural networks to model the data and extract information from the model. The results obtained revealed that the type of extract and the order of extraction influenced the concentrations of phenolic compounds as well as the antioxidant activity of the different samples studied. Also the origin of the farms from where the blueberries were harvested significantly influence those properties, showing that the blueberries from Oliveira do Hospital had less phenolic compounds and lower antioxidant activity. Also older bushes at higher altitudes seem to produce berries richer in these properties. Regarding conservation, no influence was observed for phenols but a slight influence could be detected for antioxidant activity.

Professional training in organic food production: a cross-country experience

Purpose The purpose of this paper is to characterize the agricultural activities and past experiences in professional training in the context of mobile learning in different countries (Portugal, Spain, Slovakia, Hungary, UK, Italy and Turkey). Design/methodology/approach For the survey, a questionnaire was prepared in English and Portuguese and then translated into the languages of the participating countries. It was delivered electronically for answering online by adults only. The participation was voluntary and in the end 133 consented valid questionnaires were obtained. For the treatment of the data, SPSS was used and basic descriptive statistics tools were applied, together with tests, namely, crosstabs and χ2 tests, considering a level of significance of 5 percent. Findings The results showed that the majority of the participants presently have some agricultural activity and one-third is thinking about starting one in the future. Most of the participants want to produce food organically, with significant differences among the countries studied in this paper. Most of the participants were enrolled in training activities in agriculture, especially those with higher education. This participation showed significant differences between countries as well as according to the dimension of the farms owned by the participants. A significant association was found between being a teacher in forming activities related to agriculture and being a farmer. When compared to distance learning, the training activities in classroom were the most frequent, with significant differences among the countries. Practical implications This study allowed characterizing the learning activities in the field of organic agriculture and established vision for planning of future training programs, in different countries, with maybe different social, educational and cultural realities. Originality/value Because the study included the participation of people from several countries all around Europe, the results obtained enrich the scientific area of training in organic farming, in view of distance learning vs classroom learning on a more global basis.

Designing training in organic farming on a multinational basis

Purpose – The purpose of this paper is to obtain information to characterize potential trainees seeking training programs about organic farming in the form of mobile learning. This information is expected to allow for establishing a set of guidelines to design mobile training opportunities that could match the potential clients’ wishes. Design/methodology/approach – For this survey an on-line questionnaire was used, translated into the languages of the participating countries (Portugal, Spain, Slovakia, Hungary, UK, Italy and Turkey), and in the end 133 consented valid questionnaires were obtained. The data analysis was made with SPSS and included basic descriptive statistics, crosstabs and χ2 tests, considering a level of significance of 5 per cent. Findings – The results obtained in the present study indicate that designing training programs in organic farming for a wide target population should attend to the differences between countries, which showed to significantly influence the preferences of the p...