Browsing by Author "Casal, Susana"
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- Near-infrared spectroscopy applied to the detection of multiple adulterants in roasted and ground arabica coffeePublication . Couto, Cinthia de Carvalho; Freitas-Silva, Otniel; Oliveira, Edna Maria Morais; Sousa, Clara; Casal, SusanaRoasted coffee has been the target of increasingly complex adulterations. Sensitive, non-destructive, rapid and multicomponent techniques for their detection are sought after. This work proposes the detection of several common adulterants (corn, barley, soybean, rice, coffee husks and robusta coffee) in roasted ground arabica coffee (from different geographic regions), combining near-infrared (NIR) spectroscopy and chemometrics (Principal Component Analysis—PCA). Adulterated samples were composed of one to six adulterants, ranging from 0.25 to 80% (w/w). The results showed that NIR spectroscopy was able to discriminate pure arabica coffee samples from adulterated ones (for all the concentrations tested), including robusta coffees or coffee husks, and independently of being single or multiple adulterations. The identification of the adulterant in the sample was only feasible for single or double adulterations and in concentrations ≥10%. NIR spectroscopy also showed potential for the geographical discrimination of arabica coffees (South and Central America).
- Nutritional and quality evaluation of hyperbaric stored fresh cheesesPublication . Duarte, Ricardo V.; Casal, Susana; Gomes, Ana M.; Delgadillo, Ivonne; Saraiva, Jorge A.Cow's and goat's fresh cheese (FC), two highly perishable dairy products, were stored under hyperbaric storage at room temperature (HS/RT, 50–100 MPa) and compared with refrigeration (RF, 4 °C), for 60 days. Under HS/RT (≥75 MPa), FCs presented a more stable volatile organic and fatty acid profiles, and reduced lipid oxidation rate, particularly for cow's FC, resembling more to FC prior storage, contrarily to refrigerated cheeses. No changes were observed for total protein, but free amino acids increased over time after 60 days at 75/RT of 13- and 16-fold, and at 100/RT of 14- and 8-fold, respectively in cow's and goat's FC, which may have contributed to increased protein digestibility (5.2%) observed for goat's FC after 60 days at 100/RT. In general, the results indicate the overall increased preservation performance achieved by HS/RT for cow's and goat's FC when compared with RF, slowing down FC matrix degradation, possibly leading to considerable shelf-life extension.
- Nutritional, physicochemical, and endogenous enzyme assessment of raw milk preserved under hyperbaric storage at variable room temperaturePublication . Duarte, Ricardo V.; Casal, Susana; Silva, José A. Lopes da; Gomes, Ana; Delgadillo, Ivonne; Saraiva, Jorge A.Raw milk (a highly perishable food) was preserved at variable room temperature (RT) under hyperbaric storage (HS) (50-100 MPa) for 60 days and compared with refrigeration (RF) under atmospheric pressure (AP) on quality, nutritional, and endogenous enzyme activity parameters. Overall, a comparable raw milk preservation outcome was observed between storage under AP/RF and 50/RT after 14 days, with similar variations in the parameters studied indicating milk degradation. Differently, even after 60 days (the maximum period studied) under 75-100/RT, a slower milk degradation was achieved, keeping most of the parameters similar to those of milk prior to storage, including pH, titratable acidity, total solid content, density, color, viscosity, and volatile organic and fatty acid profiles, but with higher free amino acid content, signs of an overall better preservation. These results indicate an improved preservation and enhanced shelf life of raw milk by HS/RT versus RF, showing HS potential for milk and highly perishable food preservation in general.