Percorrer por autor "Derbassi, Nabila Ben"
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- Applying Response Surface Methodology to Phenolic Compounds from Arbutus unedo: Case Studies with Ultrasound and Dynamic Maceration ExtractionPublication . Pedrosa, Mariana C.; Derbassi, Nabila Ben; Fernandes, Filipa Alexandra; Dias, Maria Inês; Heleno, Sandrina A.; Carocho, Márcio; Barros, LillianArbutus unedo L. is a small Mediterranean plant, being fgound mostly in southern Europe, north eastern Africa, Ireland, Palestine and the Canary Islands, and have been studied for its chemical composition.
- Arbutus unedo leaf extracts as potential dairy preservatives: case study on quark cheesePublication . Derbassi, Nabila Ben; Pedrosa, Mariana C.; Heleno, Sandrina A.; Fernandes, Filipa Alexandra; Dias, Maria Inês; Calhelha, Ricardo C.; Rodrigues, Paula; Carocho, Márcio; Ferreira, Isabel C.F.R.; Barros, LillianThe plant kingdom is an endless source of molecules that can be applied in almost all realms of society. The food industry has profited from the use of plants and their derived materials for many decades. Recently, the food industry has been looking into plants to find different ways of either preserving, coloring or sweetening foods. In this work, leaf extracts of Arbutus unedo L. obtained by dynamic maceration and ultrasound assisted extraction with prior optimization of their extraction conditions through the response-surface methodology, were incorporated in quark cheese as natural preservatives and analyzed over 8 days of shelf-life. Both extracts showed antioxidant activity with no toxicity towards primary cell lines at the maximum tested concentration, as well as antibacterial activity, especially against Gram-positive strains. After their incorporation in quark cheese, no significant changes were observed in the nutritional profile and physical traits of the quark cheeses, while the microbial load was highly reduced in the cheese, especially using the extracts obtained from dynamic maceration. Thus, leaf extracts of A. unedo can be promising candidates for use in the food industry as natural preservatives.
- Arbutus unedo leaf extracts as potential preservatives for quark cheesePublication . Derbassi, Nabila Ben; Carocho, Márcio; Barros, Lillian; Achour, SamiThe plant kingdom is an endless source of molecules that can be applied in almost all realms of society. The food industry has profited from the use of plants and their derived materials for many decades. Recently, the food industry has been looking into plants to find different ways of either preserving, coloring or sweetening foods. These natural food additives have become a recent trend, and consumers are preferring them over synthetic and artificial food additives due to harmful effects related to their consumption. Thus, in this work, leaf extracts of Arbutus unedo L. obtained by dynamic maceration and ultrasound assisted extraction with prior optimization through response-surface methodology, were optimized to obtain the highest yields and incorporated in quark cheese, then analysed over 8 days. Both extracts showed antioxidant and antimicrobial activity with no toxicity towards cell lines at the maximum tested concentration, and while the maceration extract showed lower antioxidant activity, when incorporated in the cheeses it better inhibited the proliferation of bacteria. As expected from a food preservative, the nutritional, chemical and physical parameters were not drastically changed from the addition of the extracts although the ultrasound extract preserved cheese did preserve soluble sugars when compared to the other cheeses. Both extracts are excellent candidates to be added to quark cheese allowing its consumption for more than eight days after opening. The two natural extracts showed better results when compared to the widely used preservative, potassium sorbate, and thus, could be used as a cheese additive and its use is encouraged by the food industry.
- Plant volatiles: using scented molecules as food additivesPublication . Derbassi, Nabila Ben; Pedrosa, Mariana C.; Heleno, Sandrina A.; Carocho, Márcio; Ferreira, Isabel C.F.R.; Barros, LillianSecondary metabolism of plants produces molecules that are widely used in the food industry for many years. The demand for these molecules has been increasing, and special focus has been given to volatile molecules. Scope: The study of secondary metabolites with special focus on the volatile molecules is overviewed, explaining their bioactivities and examples of application in the food industry. Approach: Systematic analysis of volatiles and their applications. Specific analysis of volatile components of plants and their use as active packaging and airborne food preservatives. Key findings: Some work has been done regarding volatiles in terms of food preservation but is focused mostly on postharvest protection. Considering the number of studies regarding the use of volatiles, the industry should start implementing these molecules for more sustainable approaches to preservation. Conclusions: The food industry has researched plant volatiles for some years, but the focus has been almost exclusively on postharvest protection, and more research can be directed to other food categories. Technology to overcome limitations of plant volatiles is expected to improve, placing pressure on regulatory bodies to allow these molecules in foods, on par with consumer and industry preference for natural-based molecules used in foods.
- Response surface analysis of ultrasound and dynamic maceration extractions of Arbutus UnedoPublication . Derbassi, Nabila Ben; Pedrosa, Mariana C.; Heleno, Sandrina A.; Carocho, Márcio; Ferreira, Isabel C.F.R.; Barros, LillianThe use of natural plant extracts in the food industry has been common practice for many decades, but, due to the pursuit of healthier diets by consumers, has gained a new momentum, in which natural food additives, namely preservatives have been extracted from plants. The most prominent example is the use of rosemary extract (E392) as a food preservative throughout the European Union, paving the way for new extracts to be used for the same purpose, possibly with better results. In this work, the extraction of leafy parts of Arbutus unedo L. is described both through ultrasound assisted extraction (UAE) and dynamic maceration (DM), following an optimization through Response Surface Methodology (RSM) to optimize the extraction yield. For the DM the factors analyzed were (F1) “Time” which varied between 10 and 60 minutes, (F2) “Temperature” which varied between 30 and 80 ºC, and finally (F3) “Solvent” (ethanol) which varied between 0 and 100%. For the UAE, the factors were also (F3) “Solvent” and (F1) “Time”, and although the variation in solvent was the same, the time of extraction only varied between 5 and 30 minutes. Finally, the third factor was ultrasonic (F2) “Power” of the equipment that varied between 50 and 500 watts. The analyzed response for both extractions were the dry residue (Y1) which varied between 3 and 65.3 mg for UAE and 10.4 and 99.9 mg for DM. The RSM analysis rendered a quadratic model with an inverse transformation for DM, and a reduced quadratic model with no transformation for UAE. To optimize the yield of dry residue (Y1), optimization studies were performed and indicated the optimal points at which a higher yield of dry residue can be obtained, and were F1 – 57 minutes, F2 – 46 ºC and F3 – 52% of ethanol for the DM extraction. For UAE, the optimal points for the same Y1 response were F1 – 17 minutes, F2 – 380 watts and F3 – 39% of ethanol. In Figure 1 , it is clear that for DM a longer time of extraction favors the residue yield, as well as a temperature near 60 ºC, while for the UAE, time did not seem such an important factor, while the power of the ultrasonic probe was quite important. Overall, due to the lower amount of ethanol needed and the lower extraction time, UAE seems to be the best extraction technique to maximize the yield of dry residue of A. unedo , although in terms of mass, DM yielded 99 mg while UAE only 65.3mg. Other responses are currently being studied to determine the best overall extraction technique.