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- Overcoming challenges in pediatric formulation with a patient-centric design approach: a proof-of-concept study on the design of an oral solution of a bitter drugPublication . Ogbonna, John Dike N.; Cunha, Edite; Attama, Anthony A.; Ofokansi, Kenneth C.; Ferreira, Helena; Pinto, Susana; Gomes, Joana; Marx, Ítala; Peres, António M.; Lobo, José Manuel Sousa; Almeida, Isabel F.Designing oral formulations for children is very challenging, especially considering their peculiarities and preferences. The choice of excipients, dosing volume and palatability are key issues of pediatric oral liquid medicines. The purpose of the present study is to develop an oral pediatric solution of a model bitter drug (ranitidine) following a patient centric design process which includes the definition of a target product profile (TPP). To conclude on the matching of the developed solution to TPP, its chemical and microbiological stability was analyzed over 30 days (stored at 4 °C and room temperature). Simulation of use was accomplished by removing a sample with a syringe every day. Taste masking was assessed by an electronic tongue. The developed formulation relied on a simple taste masking strategy consisting in a mixture of sweeteners (sodium saccharine and aspartame) and 0.1% sodium chloride, which allowed a higher bitterness masking effectiveness in comparison with simple syrup. The ranitidine solution was stable for 30 days stored at 4 °C. However, differences were noted between the stability protocols (unopened recipient and in‐use stability) showing the contribution of the simulation of use to the formation of degradation products. Stock solution was subjected to acid and alkali hydrolysis, chemical oxidation, heat degradation and a photo degradation stability assessment. The developed pediatric solution matched the TPP in all dimensions, namely composition suitable for children, preparation and handling adapted to hospital pharmaceutical compounding and adequate stability and quality. According to the results, in‐use stability protocols should be preferred in the stability evaluation of pediatric formulations.
- Volatile-olfactory profiles of cv. Arbequina olive oils extracted without/with olive leaves addition and their discrimination using an electronic nosePublication . Marx, Ítala; Rodrigues, Nuno; Veloso, Ana C.A.; Casal, Susana; Pereira, J.A.; Peres, António M.Oils from cv. Arbequina were industrially extracted together with olive leaves of cv. Arbequina or Santulhana (1%, w/w), and their olfactory and volatile profiles were compared to those extracted without leaves addition (control). -e leaves incorporation resulted in green fruity oils with fresh herbs and cabbage olfactory notes, while control oils showed a ripe fruity sensation with banana, apple, and dry hay grass notes. In all oils, total volatile contents varied from 57.5 to 65.5 mg/kg (internal standard equivalents), being aldehydes followed by esters, hydrocarbons, and alcohols the most abundant classes. No differences in the number of volatiles were observed. -e incorporation of cv. Arbequina or Santulhana leaves significantly reduced the total content of alcohols and esters (minus 37–56% and 10–13%, respectively). Contrary, cv. Arbequina leaves did not influence the total content of aldehydes or hydrocarbons, while cv. Santulhana leaves promoted a significant increase (plus 49 and 10%, respectively). -us, a leaf-cultivar dependency was observed, tentatively attributed to enzymatic differences related to the lipoxygenase pathway. Olfactory or volatile profiles allowed the successful unsupervised differentiation of the three types of studied cv. Arbequina oils. Finally, a lab-made electronic nose was applied to allow the nondestructive discrimination of cv. Arbequina oils extracted with or without the incorporation of olive leaves (100% and 99 ± 5% of correct classifications for leave-one-out and repeated K-fold crossvalidation variants), being a practical tool for ensuring the label correctness if future commercialization is envisaged. Moreover, this finding also strengthened that olive oils extracted with or without olive leaves incorporation possessed quite different olfactory patterns, which also depended on the cultivar of the olive leaves.
- Evaluation of the effect of extracted time conditions on the phenolic content of olive pastes from cv. Arbequina and discrimination using a lab-made potentiometic electronic tonguePublication . Marx, Ítala; Rodrigues, Nuno; Veloso, Ana C.A.; Pereira, J.A.; Peres, António M.The present study investigated the effect of malaxation times (Mt: 0, 15, 30, 45 and 60 min), during the industrial extraction of cv. Arbequina oils at 25 ºC on total phenolic content and bitterness index of olive pastes. Additionally, the possibility of applying a lab-made potentiometric electronic tongue (E-tongue), comprising 40 lipid/polymer sensor membranes with cross sensitivity, to discriminate the olive pastes according to the Mt, was evaluated. The results pointed out that the olive pastes’ total phenolic contents significantly decreased (P-value < 0.001, one-way ANOVA) with the increase of the Mt (from 2.21±0.02 to 1.99±0.03 g GAE/kg olive paste), being observed a linear decreasing trend (R-Pearson = -0.910). Similarly, the bitterness index also decreased with the Mt (23.4±0.3 to 21.9±0.4 oleuropein/kg olive paste). These findings may be tentatively attributed to the migration of the phenolic compounds from the olive pastes to the extracted oil and water phases, during the malaxation process. Finally, the E-tongue signals, acquired during the analysis of the olive pastes’ methanolic extracts (methanol:water, 80:20 v/v), together with a linear discriminant analysis (LDA), coupled with a simulated annealing (SA) algorithm, allowed to establish a successful classification model. The E-tongue-LDA-SA model, based on 11 selected non-redundant sensors, allowed to correctly discriminate all the studied olive pastes according to the Mt (sensitivities of 100% for training and leave-one-out cross-validation). The satisfactory performance of E-tongue could be tentatively explained by the known capability of lipid/polymeric sensor membranes to interact with phenolic compounds, through electrostatic interactions and/or hydrogen bonds, which total content depended on the Mt.
- Sensory analysis using electronic tonguesPublication . Marx, Ítala; Veloso, Ana C.A.; Casal, Susana; Pereira, J.A.; Peres, António M.Electronic tongues include any electrochemical nonspecific multisensor device with global selectivity, aiming mimicking the human tongue taste capability. Electronic tongues have been widely and successfully applied as taste sensors in food and pharmaceutical areas showing huge potential as a complementary analytical tool for routine sensory analysis. In comparison with trained human panelists, the electronic tongue shows several advantages namely no detection fatigue, the possibility of analyzing toxic substances and performing objective analysis, while minimizing the risk of human subjectivity. This chapter aims to compile and discuss the main research advances reported in the last decade regarding the electronic tongues’ applications as taste sensors, being focused on the operating principles and types of devices. Thus, the main advantages and limitations of these fast, accurate, bioinspired potentiometric, voltammetric, and/or amperometric green sensor-based tools will be addressed, aiming to make an overview of the recent and future challenges toward industrial and commercial applications.
- Application of a lab-made electronic nose for extra virgin olive oils commercial classification according to the perceived fruitiness intensityPublication . Teixeira, Guilherme Gobbi; Dias, L.G.; Rodrigues, Nuno; Marx, Ítala; Veloso, Ana C.A.; Pereira, J.A.; Peres, António M.An electronic nose, comprising nine metal oxide sensors, has been built aiming to classify olive oils according to the fruity intensity commercial grade (ripely fruity or light, medium and intense greenly fruity), following the European regulated complementary terminology. The lab-made sensor device was capable to differentiate standard aqueous solutions (acetic acid, cis-3-hexenyl, cis-3-hexen-1-ol, hexanal, 1-hexenol and nonanal) that mimicked positive sensations (e.g., fatty, floral, fruit, grass, green and green leaves attributes) and negative attributes (e.g., sour and vinegary defects), as well as to semi-quantitatively classify them according to the concentration ranges (0.05–2.25 mg/kg). For that, unsupervised (principal component analysis) and supervised (linear discriminant analysis: sensitivity of 92% for leave-one-out cross validation) classification multivariate models were established based on nine or six gas sensors, respectively. It was also showed that the built E-nose allowed differentiating/discriminating (sensitivity of 81% for leave-one-out cross validation) extra virgin olive oils according to the perceived intensity of fruitiness as ripely fruity, light, medium or intense greenly fruity. In conclusion, the gas sensor device could be used as a practical preliminary non-destructive tool for guaranteeing the correctness of olive oil fruitiness intensity labelling.
- Estimating hydroxytyrosol-tyrosol derivatives amounts in cv. Cobrançosa olive oils based on the electronic tongue analysis of olive paste extractsPublication . Marx, Ítala; Casal, Susana; Rodrigues, Nuno; Veloso, Ana C.A.; Pereira, J.A.; Peres, António M.The estimation of hydroxytyrosol-tyrosol derivatives amounts in olive oils through the analysis of olive pastes collected during malaxation is of utmost relevance due to the relationship with the oils' health claim regarding the protection of blood lipids from oxidative stress. Olive pastes were collected during the industrial extraction of cv. Cobrançosa oils (0–60 min; 22–34 °C). Total phenolic contents of pastes' extracts were assessed (2800–5400 mg GAE/kg paste). Oils were laboratory-extracted from each paste and, after acid hydrolysis, the contents of hydroxytyrosol and tyrosol derivatives as their sum were determined (25–135, 62–120 and 68–255 mg/kg oil). Olive paste extracts were analyzed with a lab-made potentiometric electronic tongue. The device enabled estimating the total phenolic contents of the pastes (internal-validation: correlation coefficient ≥ 0.86, root mean square error ≤ 392 mg GAE/kg). Moreover, the electronic tongue allowed a more satisfactory indirect estimation of the total secoiridoids derivatives amounts of the oils (internal-validation: correlation coefficient ≥ 0.91, root mean square error ≤ 25 mg/kg), based on the olive pastes' potentiometric profiles, without requiring the oils’ posteriori invasive/destructive analysis. Thus, the electronic tongue could be foreseen as a potential tool for anticipating the health claim fulfilment during oils industrial extraction.
- Inoculation of cv. Arbequina olives with fungi isolated from leaves and its effect on the extracted oils’ stability and health-related compositionPublication . Marx, Ítala; Baptista, Paula; Casal, Susana; Rodrigues, Nuno; Cruz, Rebeca; Veloso, Ana C.A.; Pereira, J.A.; Peres, António M.Cv. Arbequina fruits were inoculated during one day with suspensions of Aureobasidium pullulans, Epicoccum nigrum or both species ( 104 spores/g olives), isolated from olive leaves, aiming to increase the phenolic content of the olive oils. Oils were extracted from non-inoculated (control) and inoculated olives, being evaluated for their oxidative stability, and phenolic composition. Compared to the control oils, those extracted from inoculated olives showed higher oxidative stability (+ 16–29%), phenolic acids contents (up to + 37%), phenolic alcohols (up to + 101%), flavonoids (up to + 154%) and secoiridoid derivatives (up to + 12%). These positive effects could be attributed to the hydrolytic activity of enzymes secreted by the studied fungi on the fruit cellular membranes and extracted phenolics, increasing the extractability and, consequently, altering the phenolic concentration. Considering the two fungi species, E. nigrum inoculation had a more significant positive impact on the contents of tyrosol, oleuropein, and ligstroside derivatives, showing an inhibition effect regarding the oleacein formation. Contrary, A. pullulans inoculation mainly resulted into an accentuated increase of luteolin and oleacein contents (3 and 12-times higher compared with control oils, respectively). Overall, no enhanced positive synergetic effect could be attributed to the inoculation with a suspension containing both fungi. The significant changes observed on the phenolic contents, due to the fungal inoculation, allowed the successful discrimination of the four types of extracted oils using an electronic tongue. This device acts as an artificial taste device allowing anticipating an impact at the oils’ basic taste sensations due to the fungi inoculation.
- Application of an electronic tongue as a single-run tool for olive oils’ physicochemical and sensory simultaneous assessmentPublication . Rodrigues, Nuno; Marx, Ítala; Casal, Susana; Dias, L.G.; Veloso, Ana C.A.; Pereira, J.A.; Peres, António M.Olive oil is highly appreciated due to its nutritional and organoleptic characteristics. However, a huge compositional variation is observed between olive oils, requiring the use of diverse analytical techniques for its classification including titration, spectrophotometry and chromatography, as well as sensory analysis. Chemical analysis is usually time-consuming, expensive and require skilled technicians, while the sensorial ones are dependent upon individual subjective evaluations, even if performed by trained panellists. This work evaluated and demonstrated the feasibility of using a potentiometric electronic tongue, comprising non-specific lipid polymeric and cross-sensitive sensor membranes, coupled with chemometric tools based on different sub-sets of sensors (from 11 to 14 sensors), to predict key quality parameters of olive oils based on single-run assays. The multivariate linear models established for 23 centenarian olive trees from different cultivars allowed predicting peroxide value, oxidative stability, total phenols and tocopherols contents, CIELAB scale parameters (L*, a* and b* values), as well as 11 gustatory-retronasal positive attributes (green, sweet, bitter, pungent, tomato and tomato leaves, apple, banana, cabbage, fresh herbs and dry fruits) with satisfactory accuracy (0.90 ± 0.07 ≤ R2 ≤ 0.98 ± 0.02 for the repeated K-fold-CV procedure, which ensured that 25% of the data was used for internal-validation purposes). The electronic tongue device had an accuracy statistically similar to that achieved with standard analytical techniques, pointing out the versatility of the device for the fast and simultaneous chemical and sensory analysis of olive oil.
- Emerging trends of electrochemical sensors in food analysisPublication . Marx, ÍtalaFood quality and safety pose an increasing threat to human health worldwide. The development of analytical methods and techniques to ensure food quality and safety is therefore of great importance. For this purpose, electrochemical sensors are emerging as suitable analytical tools as they provide a low-cost and sensitive option based on portable devices capable of rapidly detecting a range of analytes with high sensitivity and specificity. They have the potential to overcome the restrictions and limitations of traditional methods. Additionally, these sensors have special recognition capabilities for a wide range of molecules, with high stability under extreme experimental conditions. This paper reviews the progress of using electrochemical sensors applied to the food industry, namely to the field of quality and safety evaluation. Future perspectives and challenges are also discussed.
- Does water addition during the industrial milling phase affect the chemical-sensory quality of olive oils? The case of cv. Arbequina oilsPublication . Marx, Ítala; Casal, Susana; Rodrigues, Nuno; Cruz, Rebeca; Veloso, Ana C.A.; Pereira, J.A.; Peres, António M.At olive oil industrial extraction, water addition is a practice overcoming the formation of thick pastes. The effect of water addition (0 to 6.2%, kgadded water/kgolives), during the industrial milling of cv. Arbequina olives, on the oils’ chemical-sensory quality, was evaluated. Despite the extra virgin olive oil classification, compared with the water incorporation (1.2–6.2%), extraction without water addition resulted into oils that showed less primary oxidation (lower peroxide values and K232), greater total phenolic content (+12–22%) and higher oxidative stability (+22–31%). No water addition increased the oils secoiridoids content (+5–13%), mainly oleacein (+27–79%). Oils extracted without water addition had a more intense ripe fruity sensation (≥ +11%) but lower fruit intensities (at least - 4%). Thus, the quality and stability of the cv. Arbequina oils can be favoured if extracted without adding water during the olives industrial milling.