Percorrer por autor "Mohamed, Mustafa H.M."
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- Egyptian pumpkin by-product extracts as natural food preservativesPublication . Leichtweis, Maria Gabriela; Molina, Adriana K.; Pereira, Carla; Pires, Tânia C.S.P.; Calhelha, Ricardo C.; Mohamed, Mustafa H.M.; Oliveira, Beatriz; Ferreira, Isabel C.F.R.; Barros, LillianThe correlation between synthetic food additives and their adverse health effects has aroused the concern of consumers, which increasingly prefer natural food alternatives. On the other hand, industries have faced the challenge of meeting consumers’ expectations with ready-to-use healthy products with a long shelf life. The present work aimed to investigate the by-products of pumpkin industrial processing as cheap sources of preservative compounds for food application. For that purpose, the seeds, peels, and fibers of five pumpkin genotypes cultivated in Egypt, namely ‘Butternut Squash’, ‘Golden Cushaw’, ‘Dickinson’, ‘Halloween’, and ‘Honey Delite’, were evaluated regarding their preservative potential. The hydroethanolic extracts of these by-products were assessed for their antioxidant activity, by TBARS in porcine brain homogenates, antimicrobial activity, against eight bacterial and two fungal strains with relevance in food contamination, and cytotoxicity in a primary culture of non-tumor hepatic cells (PLP2). Regarding the antioxidant activity, it was tested using a cell-based assay that has the advantage of evaluating oxidizable biological targets. In general, all the samples presented great capacity of lipid peroxidation inhibition. The seeds showed the best results in four of the five evaluated genotypes, with IC50 values ranging from three to almost thirteen times higher than the positive control Trolox. In addition, all samples were able to protect against at least one of the eight tested bacterial strains. The seeds of ‘Honew Delite’ stood out, inhibiting six bacteria and the two tested fungi, followed by the peel of ‘Butternut Squash’, which inhibited five bacterial and two fungal strains. Actually, all the peel samples protected against at least three bacteria and one fungus. Furthermore, none of the tested samples showed cytotoxic activity against the non-tumor porcine liver cells up to the maximum tested concentration of 400 μg/mL, which is a first validation of their safe application in food. Through these results, it is possible to point out the potential of pumpkin by-products as sources of preservative compounds, contributing to the gradual reduction of synthetic additives in food. On the other hand, it also promotes more sustainable industrial processes, by reusing pumpkin by-products.
- Sustainable use of pumpkin: characterization of the pulp and valorization of by-products in obtaining preservative extractsPublication . Leichtweis, Maria Gabriela; Molina, Adriana K.; Pereira, Carla; Pires, Tânia C.S.P.; Calhelha, Ricardo C.; Mohamed, Mustafa H.M.; Oliveira, Beatriz; Ferreira, Isabel C.F.R.; Barros, LillianIn the search for more sustainable industrial processes, the use of by-products from food production is an important strand [1]. Currently, the food industry has increasingly developed practical, ready-to-eat, and long shelf-life food products. How ever, this demand involves the use of synthetic food additives, which are associated with harmful effects on consumers health. Aiming to promote sustainability allied to the replacement of synthetic additives by natural alternatives, this work proposed the use of by-products from pumpkin processing, as a matrix for obtaining preservative compounds with potential to be applied in a product of pumpkin pulp. For that purpose, five different pumpkins cultivated in Egypt, namely ‘Butternut Squash’, ‘Golden Cushaw’, ‘Dickinson’, ‘Halloween’, and ‘Honey Delite’ were assessed. The pulp was evaluated regarding its nutritional value and chemical composition, in terms of free sugars (HPLC-RI), fatty acids (GC-FID), tocopherols (HPLC-FLD) and organic acids (UFLC-PDA). The by-products, more specifically the seeds, fibers, and peel, were evaluated for their antioxidant and antimicrobial capacity, as well as their cytotoxicity. All the pulp samples presented carbohydrates as the major compounds, followed by protein and fibers, with low content of fat. Regarding free sugars, fructose was predominant in all samples, except for the ‘Golden Cushaw’, which presented high levels of sucrose. Glucose was also present in high levels in most of the samples, and considerable contents of trehalose and raffinose were also found. Regarding fatty acids profile, the pulp revealed to be rich in saturated and polyunsaturated fatty acids, representing, respectively, about 40-50% of the total fatty acids, composed mainly by palmitic (C16:0), linoleic (C18:2n6c), α-linolenic (C18:3n3), and stearic (C18:0) acids. Regarding organic acids, all pulp samples presented malic and fumaric acids. In the samples that presented quinic acid, this was present in major quantity. Oxalic acid and traces of shikimic and citric acids were also detected. Also, the samples showed αand γisoforms of tocopherol, being the last one the most abundant. In addition to the rich nutritional composition of the pulps, as expected, the by-product extracts showed excellent preservative capacity. In the TBARS assay, the samples showed great capacity to inhibit lipid peroxidation, mainly the seeds and two of the five fibers. Moreover, all samples presented antibacterial capacity, inhibiting the growth of one to six of the eight tested bacteria. Also, some samples were capable of inhibiting the growth of the two fungal strains tested, with the peels standing out, protecting against at least three bacteria and one fungus. Additionally, none of the samples presented cytotoxic activity against the non-tumor porcine liver cells (up to 400 μg/mL), thus expressing its safety for food application. With this, it is possible to verify the potential use of pumpkin by-products as a source of natural preservatives, as well as the great nutritional value of the pulp, which can be further explored in the development of new pulp products preserved with their processing by-products. This favours a circular economy through sustainability.
- Uso sustentável da abóbora: extratos de subprodutos de abóbora egípcia como conservantes naturalPublication . Leichtweis, Maria Gabriela; Molina, Adriana K.; Pereira, Carla; Pires, Tânia C.S.P.; Calhelha, Ricardo C.; Mohamed, Mustafa H.M.; Oliveira, Beatriz; Ferreira, Isabel C.F.R.; Barros, LillianAtualmente, a indústria alimentícia tem desenvolvido cada vez mais produtos práticos, prontos para consumo e com longa vida útil.