Percorrer por autor "Barroca, M. J."
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- Chemical composition of Crataegus monogyna – Preliminary StudiesPublication . Dulyanska, Y.; Cruz-Lopes, Luísa; Esteves, Bruno; Barroca, M. J.; Carvalho, L. B.; Gonçalves, Fernando Jorge; Domingos, Idalina; Ferreira, José; Guiné, Raquel P. F.
- Drying of Maritime Plants: Effect on Antioxidant ActivityPublication . Guiné, Raquel P. F.; Barroca, M. J.; Mansinhos, I.; Silva, A. M.Salicornia and Sarcocornia belong to the same family and have similar morphological and organoleptic properties. [1]. The objective of this work was to evaluate the antioxidant activity extracts obtained from the plants in the fresh state and after being dried. Their extracts may represent a valuable source for developing novel food products (antioxidant-enriched foods), and/or table salt substitutes that satisfy the desires of consumers in terms of health benefits and sensorial acceptance. The plants (Salicornia macrostachya Moric. and Sarcocornia perennis) were collected from Portuguese salt pans, in the central region of Portugal and the aerial parts were used as raw material. The drying of plants was performed in a pilot tray drier at 40 ºC and air velocity of 1.5 ms -1 , for approximately three days. The initial moisture content was 92.30% and 84.24%, respectively, for Salicornia and Sarcocornia. The drying was carried out until reaching a final moisture content of 5%. The antioxidant activity was measured with DPPH method. Regarding the DPPH method, the results showed that the incubation time of 15 minutes is enough to measure the DPPH scavenging activity in halophyte extracts in the tested range of extract concentrations (Figure 1). However, the time defined to measure the DPPH scavenging activity was fixed at 30 minutes, since this was the common time in different laboratorial protocols. For Salicornia, the values of inhibition IC 50 were 1.09 and 1.12 mg/mL for the fresh and dried samples, respectively. For Sarcocornia, the values of IC 50 were 1.42 and 1.02 mg/mL for the fresh and dried samples, respectively. The results showed that the convective air-drying process at 40 ºC is adequate to improve the shelf life of the two halophyte plants, since the antioxidant activity was maintained or even improved as compared with the fresh samples. This might be due to a response of the plant to the stress induced by the heat and humidity conditions in the drying chamber. In this way, it was concluded that both studied halophyte plants constitute a valuable source of natural antioxidants when they are consumed as foods either in the fresh or dried states. Additionally, their extracts may represent a valuable source for developing novel antioxidant-enriched food products aimed to meet the desires of consumers who seek for health-beneficial foods.
- Modelling in Drying Technology of Food Products: A Comprehensive Survey.Publication . Guiné, Raquel; Golpour, I.; Barroca, M. J.; Kaveh, M.Drying of foods has been used to preserve food and agricultural products since immemorial times. However, still nowadays it assumes a prominent place among food processing technologies applied industrially to extend shelf life of foods. Although having some important advantages, like the reduction in water activity and subsequent minimization of degradation reactions of biological, chemical or enzymatic nature, reduction in size for transportation and storage or avoidance of refrigeration systems during transportation and storage, it is also true that drying brings high energy costs and some possible undesirable changes in quality parameters. Hence, the optimization of drying processes is of the utmost importance to minimize energy costs and maximize quality. Mathematical modelling in food process engineering allows important savings, while also guaranteeing the safety of industrial plants and workers, and finally achieving ultimate quality of the dried foods. Because artificial neural networks (ANNs) have been gaining importance in the context of many problems in the fields of engineering, among others, this chapter aims to do a review of scientific literature about the use of artificial neural networks to modelling and optimization of food drying processes. Finally, opportunities and restrictions of the ANNs technique for drying process simulation, optimization, and control are achieved to guide future R&D in this area.
- Study of antioxidant activity in extracts from fresh and dried halophyte plantsPublication . Barroca, M. J.; Mansinhos, I. F. P.; Guiné, Raquel P. F.; Silva, A. M.Salicornia macrostachya Moric. and Sarcocornia perennis subsp. alpini belong to the same family and share morphological and organoleptic characteristics. The visually appealing in terms of freshness, color and particular taste, nutritional values and health benefits are recognized by their consumers as attributes that warrant their gourmet status. The objective of this work was to study the effect of incubation time on antioxidant capacity of these plants. Moreover, the work investigates the antioxidant activity of the extracts of the two halophyte plants and evaluates the effect of air drying the plants at 40 ºC and the procedure of concentration the extracts before evaluating the antioxidant activity, measured with DPPH method. The two halophyte plants, Salicornia macrostachya Moric. and Sarcocornia perennis subsp. alpini were collected from Portuguese salt pans, in the central region of Portugal, and the aerial parts were used as raw material. The drying of plants was performed in a pilot tray drier at 40 ºC and air velocity of 1.5 m/s, for approximately 3 days. The DPPH free radical scavenging of the methanolic extracts was analysed in extracts obtained from fresh and dried plants. The determination of the antioxidant activity was made with the DPPH radical. The results showed that, in summary, and regarding the DPPH assay, the incubation time of 15 minutes is enough to measure the DPPH scavenging activity in halophyte extracts. Furthermore, the convective air-drying process at 40 ºC showed to be an appropriate process to increase the shelf life of the halophyte plants and the antioxidant capacoty of the halophyte plants, as a response to the stress provoked by the heat and humidity drying conditions. The plant extracts showed significant antioxidant potential, with high radical scavenging activity. The extracts prepared from Salicornia macrostachya and Sarcocornia perennis had, respectively, values of IC50 equal to 1.09 and 1.42 mg/mL. However, the antioxidant activity of extracts obtained from dried plants increased much more since the IC50 decreased to around 0.6 mg/mL, regardless of the halophyte plant. Both halophytes plant are a valuable source of natural antioxidants and nutrients for use in food. Besides, their crude extracts may represent a valuable source for developing novel food products (antioxidant-enriched foods) that satisfy the desires of consumers in terms of health benefits and sensorial acceptance.
- The drying process of Sarcocornia perennis: impact on nutritional and physico-chemical propertiesPublication . Barroca, M. J.; Guiné, Raquel P. F.; Amado, A. M.; Ressurreição, S.; da Silva, A. Moreira; Marques, M. P. M.; de Carvalho, L. A. E. BatistaThe Sarcocornia genus is an extreme salt-toler- ant plant that can be cultivated in saline habitats almost worldwide. To preserve Sarcocornia perennis, convective drying experiments were conducted and their effects on the physico-chemical properties and phenolic content of the plant were studied using conventional and vibrational spectroscopy techniques. The drying process of Sarcocor- nia perennis at temperatures of 40 C, 50 C, 60 C and 70 C revealed three periods of convective drying process with drying times ranging between 4.5 and 24.9 h, respectively to higher and lower temperatures. The heating- up period can be neglected as compared with the drying process, and the duration of constant rate period, as a percentage of the total drying time, ranged between 34 and 20% respectively at 40 C and 70 C. The Modified Page model was proposed to describe the drying process at the different temperatures. From a nutritional point of view, this halophyte plant may be considered as a good source of fibres, phenolic compounds and natural minerals, such as sodium, potassium, calcium and magnesium. The convec- tive drying, in the temperature range currently used, was found to preserve the colour, nutritional characteristics and phytochemical value of Sarcocornia perennis. These results were confirmed by FTIR-ATR and highlight the potential use of the dried plant in novel food products.
- The duality of innovation and food development versus purely traditional foodsPublication . Guiné, Raquel; Florença, S. G.; Barroca, M. J.; Anjos, O.Background: Intangible cultural heritage includes knowledge and skills transmitted throughout times, and this also applies to the food sector. Traditional knowledge assumes important social and economic value, which is relevant both for sectorial clusters as well as for majority social groups. Scope and approach: The objective of this review was to analyse the constraints and motivations for development in the sector of traditional foods, from the point of view of marketing and consumer trends. This review was based on published works searched for in scientific databases, such as ScienceDirect, PubMed, Scopus and web of Science. Key findings and conclusions: This review showed that the value of tradition, recognized in many sectors of society, is also important in the food sector, which is particularly rich in ethnical elements, local ingredients, traditional formulations and social aspects, linked not only to the food itself but also to the act of eating and sharing. However, the food industry seeks development of new products that follow modern trends and are able to conquer today’s consumers, while at the same time maintaining the identity of specific products, valued as traditional.