Browsing by Author "Galhano dos Santos, Rui"
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- Acrylamide mitigation in bakery productsPublication . Jesus, Susana; Delgado, Inês; Brandão, Carlos; Galhano dos Santos, Rui; Castanheira, IsabelThe aim of this study was the determination of acrylamide in Portuguese bakery and its reduction in a bakery product. Acrylamide is considered by the International Agency for Research on Cancer as a carcinogenic compound to animals and probably to humans. For this study a total of 30 samples of god bread, “trouxa filó”, pies, ham and cheese rollings, muffins, pastels, and cookies were randomly collected in several commercial establishments. Sample preparation involved solid phase extraction and for the quantification of acrylamide a ultra-performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS) was used. The ham and cheese rolling and “trouxa filó” had the highest amount of acrylamide, 3743 µg/kg, and 3862 µg/kg, respectively. The results also showed that caramel cookies, butter cookies, Greek cookies and cocoa cookies do not exceed the EFSA indicative value (500 μg/kg) (EFSA, 2015). Pie samples(686-1084 μg/kg), god's bread(995 μg/kg), pastels(527-809 μg/kg) and muffins(676-1057μg/kg) contain high levels of acrylamide when compared to the values found in the literature for bakery products, 198 μg/kg (Mojska, Gielecińska, Szponar, & Ołtarzewski, 2010). Given the obtained results, tests were carried out in order to reduce the concentration of acrylamide. A bakery product was prepared to which four different reducing agents (A, B, C and D) were individually added. The effect of each agent on acrylamide formation was evaluated. Results showed that mixture B obtained an acrylamide reduction of 5.6%. On the other hand, the remaining mixtures increased the production of the contaminant. Yet, it was found that the decrease obtained with mixture B is still not sufficient since it remains above the indicative value of EFSA. Thus, further studies are necessary in order to achieve a higher percentage of reduction of acrylamide. Progress studies are ongoing with other reducing agents and flours.
- Acrylamide mitigation in rye and oat breadPublication . Jesus, Susana; Delgado, Inês; Brandão, Carlos; Galhano dos Santos, Rui; Castanheira, IsabelBackground and objective(s):Acrylamide is a carcinogenic substance for animals and to humans. The harmful effect of such compound was later confirmed, and recently the acrylamide was considered a neurotoxic and genotoxic substance1. This contaminant has been found in carbohydrate-rich foods since 20022. There are many studies regarding several mitigation strategies, however it is need to change the manufacturing processes3. The aim of the study was to reduce the acrylamide content in bread. Materials and methods:It was selected oat and rye breads which are consumed ones daily by the population. The confection trials of rye and oat breads were made with the addition of 15 polyphenols-rich additives separately. For detection and quantification of acrylamide was used the ultra-efficiency liquid chromatography coupled to a mass detector. Results:In oat bread was found that only one additive allowed 77.8% reduction of acrylamide. Such value was below of the indicative value published by EFSA, 150 μg/kg2. In rye bread was obtained a maximum reduction of 79%. Comparing the rye bread results with the indicative value of EFSA, only one bread was lower than 150 μg/kg2. However, further studies on the quantity of additives added are needed, due to the close results of the indicative value. Discussion and conclusion(s):In general, there was a wide variability in acrylamide levels among the two breads. These differences can be caused by the nutritional composition of each flour. A more detailed study of the mechanism of the reduction of these additives in different nutritional composition flours is, therefore, necessary. References: 1. Claeys, W. et al. Reassessment of the acrylamide risk: Belgium as a case-study. Food Control 59, 628–635 (2016). 2. EFSA. Scientific Opinion acrylamide in Food. EFSA Journal 8, (2015). 3. Pedreschi, F., Mariotti, M. S. & Granby, K. Current issues in dietary acrylamide: Formation, mitigation and risk assessment. J. Sci. Food Agric. 94, 9–20 (2014).
- Auto-Disinfectant Acrylic Paints Functionalised with Triclosan and Isoborneol - Antibacterial AssessmentPublication . Machado Querido, Micaela; Paulo, Ivo; Hariharakrishnan, Sriram; Rocha, Daniel; Pereira, Cristiana Costa; Barbosa, Nuno; Bordado, João Moura; Teixeira, João Paulo; Galhano dos Santos, RuiEnvironmental surface contamination with microorganisms is a serious concern worldwide. Triclosan and isoborneol present good antimicrobial activity. Their immobilisation to paint substrates allows for development of a material that stays effective over a longer time. In this work, we disclosed the preliminary studies to evaluate the antimicrobial activity of the active molecule after being functionalised with isocyanates for further immobilisation on the paint substrate. Overall, the newly developed non-release antimicrobial coating provides an effective way of preventing the spread of diseases and has been proven to inhibit bacterial growth and with a considerable antimicrobial activity towards S. aureus, E. coli, and K. variicola at the tested concentrations.
- Self-Disinfecting Paints with the Natural Antimicrobial Substances: Colophony and CurcuminPublication . Querido, Micaela Machado; Paulo, Ivo; Hariharakrishnan, Sriram; Rocha, Daniel; Barbosa, Nuno; Galhano dos Santos, Rui; Bordado, João Moura; Teixeira, João Paulo; Pereira, Cristiana CostaThe risk of infection arising from indirect sources-namely, contaminated surfaces-has been proved, particularly in healthcare facilities. In the attempt to minimize this problem, innumerable research projects involving the development of surfaces with self-disinfecting properties are being conducted. In this work, wall-paints with self-disinfecting properties were developed with the scope of being applied in environments prone to contamination, such as those at healthcare settings. Our approach was to develop new paint formulations containing two natural plant-based products with known antimicrobial activity-colophony (CLF) and curcumin (CUR). The natural substances were separately incorporated on a commercial paint and their antibacterial activity was evaluated with several bacterial species following ISO 22196. To assess the paints' safety, cytotoxicity tests were performed on HaCaT and A549 cell lines, using tests on extracts and direct contact tests, as suggested by the standardized protocol ISO 10993. In general, both paints containing CLF and CUR were able to reduce the bacterial growth after 24 h, compared with the control, the commercial unmodified paint. Colophony was even able to reduce the number of culturable bacteria by over 2 log for Staphylococcus aureus, Escherichia coli, and Bacillus cereus. Regarding the cytotoxicity tests performed (WST-1, NRU, and LDH), both formulations revealed promising results regardless of the methodology used.