ESTGL - DGAT - Artigo em revista científica, indexada ao WoS/Scopus
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- Comparison of milk consumption habits across two European countries: Pilot study in Portugal and FrancePublication . Guiné, Raquel P. F.; Florença, Sofia de Guiné e; Bréjon, M.; Gonçalves, João Carlos; Ferreira, Manuela; Barroca, Maria João; Fragata, AnabelaHumans have been consuming milk obtained from domesticated animals since ancient times. Milk is a very complete food with important nutrients that can sup- port life. However, the patterns of consumption of milk have been shifting. On one hand, due to the increase in the number of people with intolerances (to lactose, for example), and on the other hand, due to some trend to avoid foods from animal origin owing to speci fi c convic- tion (like animal welfare, for example). In this context, this study focused on the milk consumption patterns in two di ff erent European Countries and the evaluation of pos- sible di ff erences. The object of study was milk obtained from animal sources, namely, cows, and no other derived fermented dairy products were included. For the develop- ment of the study, a questionnaire survey was applied to a sample of 542 participants from both countries using the Internet. The results showed that a high percentage of participants in both countries consume milk regularly, and the usual amount varies between 125 and 250 mL per day. For those who do not consume milk, the most relevant reason pointed out in both countries was because they do not feel the need to consume it. While in France, a high percentage also do not consume because they do not like milk, and in Portugal, a high percentage do not consume milk due to lactose intolerance. The most con- sumed is semi-skimmed milk, and preferences are towards consuming plain milk or consuming it with chocolate. Signi fi cant di ff erences were found in the consumption of white brands, which are preferred in France, while in Portugal, consumers prefer commercial brands, as well as the preferred package, tetra packs for the Portuguese, while the French prefer plastic bottles. In conclusion, although the results showed some similar trends among the participants from both countries, some di ff erences were also identi fi ed that can be used to better plan public policies in both countries.
- Evaluation of the antioxidant activity of extracts obtained form cherry seeds.Publication . Dulyanska, Y.; Cruz-Lopes, Luísa; Esteves, Bruno; Ferreira, José; Domingos, Idalina; Lima, M. J. Reis; Correia, Paula; Ferreira, Manuela; Fragata, Anabela; Barroca, Maria João; Silva, A. M.; Guiné, Raquel P. F.Annual cherry production in Portugal is around 19,000 tonnes, in an area of about 6,450 ha and covering about 11,100 farms, concentrated in some northern and central interior territories. It is also in these regions that in recent decades there has been a significant increase in farms specialized in the production of cherry, using new cultivars and new technologies in a business production model. Apart from being consumed in fresh form, cherries are used for many food preparations, like sweets, jellies or confectionary. In the plants that transform cherries, a significant amount of cherry seeds (also called cherry pits) is generated as residue or waste. The possible usage of these residues as raw material for extraction of compounds with antioxidant properties is beneficial in term of economic value as well as environmental impact. Hence, the objective of this work was to obtain extract rich in compounds with antioxidant activity from cherry seeds. The cherry seeds were obtained from a local waste management company, Nutrofertil, located in Tondela, in the district of Viseu (Portugal). They were grinded and then submitted to extraction procedures testing different operating conditions: magnetic stirrer versus ultrasound, different solvents (methanol, ethanol, water) and temperatures (from 35 ºC to 80 ºC). For the obtained extracts antioxidant activity was evaluated through spectrophotometric methods, using the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid)) radicals, and also the Ferric Reducing Antioxidant Power Assay (FRAP). All measurements were replicated at least trice, and were expressed as mg Trolox equivalents per gram (mg TE/g). The results obtained for the different experimental conditions indicated that least efficient extractions at ambient temperature were obtained with methanol using magnetic stirrer and with water using ultrasounds, for which the antioxidant activities measured by the DPPH method were 0.26 and 0.33 mg TE/g and by the ABTS method were 0.82 and 0.86 mg TE/g, respectively. Most efficient methods were water:ethanol (at 50% concentration) and water (100%), using magnetic stirrer in both cases. Highest antioxidant activity was obtained for water:ethanol by the DPPH method (0.72 mg TE/g) and for water (100%) by the ABTS method (1.25 mg TE/g). Tests with different concentrations for the aqueous solutions of ethanol and at different temperatures revealed that with increasing concentration of water the antioxidant diminished, from 0.62 to 0.27 mg TE/g at 35 ºC using the DPPH method. Additionally, the variation in temperature allowed reaching a maximum extraction of compounds with antioxidant activity at 70 ºC and decreasing thereafter. The maximum values obtained were registered at 70 ºC for all cases and were 0.74 mg TE/g for the water:ethanol 50:50 (v/v) by the DPPH method, 2.16 mg TE/g for the water:ethanol 60:40 (v/v) by the ABTS method and 3.43 mg TE/g for the water:ethanol 60:40 (v/v) by the FRAP method. The results obtained by the different methods were concordant in terms of the observed trends but giving different values of the measured antioxidant activity, which is a common characteristic observed in these types of evaluation techniques. This research allowed establishing some operational conditions that should be selected in order to maximize the extraction of compounds with antioxidant activity from cherry seeds. The use of ultrasounds was not found beneficial and the magnetic stirrer technique revealed to be more useful. Also the use of methanol was not found suitable, which is a good point given that this solvent is more pollutant and has more problems of toxicity. With respect to temperature, it was found that temperatures higher than 70 ºC are not beneficial because they induce the degradation of some bioactive compounds thus reducing the antioxidant activity of thee extracts.
- Extraction of Phenolic Compounds from Cherry Seeds: A Preliminary StudyPublication . Dulyanska, Yuliya; Cruz-Lopes, Luísa; Esteves, Bruno; Ferreira, José; Domingos, Idalina; Lima, Maria João; Correia, Paula; Ferreira, Manuela; Fragata, Anabela; Barroca, Maria João; Moreira da Silva, Aida; Guiné, Raquel P. F.Agri-food waste has proved to be a valuable bioresource that can be used to obtain a variety of valuable materials, ingredients and chemicals. The optimum conditions for extracting bioactive compounds from sweet cherry seeds (SCS) with different solvents and temperatures were tested in this work. The choice criteria were based on the most efficient extracting capacity while looking for cleaner techniques with lower health or environmental impacts. Some extracting solvents (methanol, ethanol and water) were tested in different combinations and temperatures. The obtained extracts were evaluated for total phenolic compounds and some families of phenolics as well, using spectrophotometric methods. The results obtained showed that the highest extraction of total phenolic compounds was at 70 °C with 60:40 ratio water:ethanol (2.65 mg GAE/g), while maximum flavonoids were obtained at 80 °C and 50% ethanolic aqueous solution (7.26 mg QE/g). The highest value for ortho-diphenols was 21.47 mg GAE/g for 50 °C and water:ethanol 50:50 solution. The highest proanthocyanidins and flavonols were obtained for 50:50 solution at 70 °C (6.43 mg CE/g and 3.88 mg QE/g, respectively), while the same solution at 80 °C allowed obtaining maximum phenolic acids (1.68 mg CAE/g). The extraction of anthocyanins was found to vary significantly with concentration and temperature, being highest in the range 35–40 °C, when using an 80:20 water:ethanol solution. Hierarchical clustering showed three clusters, while factor analysis resulted in two factors and four groups of samples. In conclusion, it was found that extracts obtained from sweet cherry seeds have relevant bioactive compounds with applications in the food, pharmaceutical or cosmetic industries.