Percorrer por autor "Barradas, Carla"
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- Mead production improvements after using a factorial desingPublication . Gomes, Teresa; Barradas, Carla; Dias, Teresa; Andrade, João Verdial; Morais, Jorge Sá; Ramalhosa, Elsa; Estevinho, Leticia M.ln the north of Portugal, and in particular in Trás-os-Montes region, there is sometimes an overproduction of honey. Mead is one of the possibilities to overcome this problem. However, most of the time, mead is not produced in a standardized, but empirical and handmade form.
- Mead production: comparison of different production scales (preliminary results)Publication . Gomes, Teresa; Barradas, Carla; Dias, Teresa; Andrade, João Verdial; Morais, Jorge Sá; Ramalhosa, Elsa; Estevinho, Leticia M.Mead production represents a possible economic alternative to honey producers that intend to obtain honey products with surplus value. From that the present work aims to study the influence of using different production scales on the quality of the final mead obtained and on the process performance. Increasing the production scale almost ten times (1.5 to 20 L), some differences were observed. Maximum specific growth rates equal to 0.045 and 0.038 h-1 were obtained for fermentations carried out at 1.5 and 20 L, respectively. The time course of glucose and glycerol were similar for both production scales. Nevertheless, slight differences at the end of the fermentations were observed for fructose and acetic acid. In relation to ethanol, a higher final concentration was found in the pilot-scale, resulting in a higher ethanol yield. In conclusion, these preliminary results are a good promise to local honey producers who intent to obtain large-productions of mead.
- Mead production: comparison of different production scales (preliminary results)Publication . Gomes, Teresa; Barradas, Carla; Dias, Teresa; Andrade, João Verdial; Morais, Jorge Sá; Ramalhosa, Elsa; Estevinho, Leticia M.Mead production represents a possible economic alternative to honey producers that intend to obtain honey products with surplus value. From that the present work aims to study the influence of using different production scales on the quality of the final mead obtained and on the process performance. Increasing the production scale almost ten times (1.5 to 20 L), some differences were observed. Maximum specific growth rates equal to 0.045 and 0.038 h-1 were obtained for fermentations carried out at 1.5 and 20 L, respectively. The time course of glucose and glycerol were similar for both production scales. Nevertheless, slight differences at the end of the fermentations were observed for fructose and acetic acid. In relation to ethanol, a higher final concentration was found in the pilot-scale, resulting in a higher ethanol yield. In conclusion, these preliminary results are a good promise to local honey producers who intent to obtain large-productions of mead.
- Optimization of mead production using response surface methodologyPublication . Gomes, Teresa; Barradas, Carla; Dias, Teresa; Andrade, João Verdial; Morais, Jorge Sá; Ramalhosa, Elsa; Estevinho, Leticia M.The main aim of the present work was to optimize mead production using Response Surface Methodology. The effects of temperature (x1: 20–30 ºC) and nutrients concentration (x2: 60–120 g/hL) on mead quality, concerning the final concentrations of glucose (Y1), fructose (Y2), ethanol (Y3), glycerol (Y4) and acetic acid (Y5), were studied. Twelve operational conditions were tested. No delays and moods were observed during fermentations. The second order polynomial models determined produced satisfactory fittings of the experimental data with regard to glucose (R2= 0.646, p = 0.001), ethanol (R2= 0.741,p = 0.049), glycerol (R2= 0.899, p = 0.002), fructose (R2= 0.902, p = 0.033) and acetic acid (R2= 0.913,p = 0.001). The optimum extraction conditions determined in order to maximize the combined responses were 24 ºC and a nutrients concentration of 0.88 g/L. The mead produced under these conditions had the following characteristics: ethanol concentration of 10.2%, acetic acid 0.54 g/L, glycerol 7.8 g/L, glucose 1.8 g/L and fructose 2.5 g/L. These values were in agreement with the predicted and were within the safe limit established for acetic acid and the recommended range for glycerol. Furthermore, the residual sug- ars concentration was also low, decreasing the possibility of occurring undesirable refermentations.