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Browsing by Issue Date, starting with "2016-10-02"

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  • Occurrence of acrylamide in Portuguese bread
    Publication . Jesus, Susana; Delgado, Inês; Rego, Andreia; Brandão, Carlos; Castanheira, Isabel
    Acrylamide is known for its potential health hazards and it is present in diverse food, like bread, coffee and potato. The aim of this study was to analyze the acrylamide content of confectioned bread in fifty- four different pastries. Acrylamide levels obtained were high, ranging between 59 and 1273 µg/kg. Only two bakeries had lower quantities of acrylamide than the indicative value of EFSA, 150 µg/kg. These differences can be associated with the products confection process, but also with the use of different recipes bread.
    2016-10-02Conference object Restricted access Show more
  • Instrumental Blank Samples Assessed Through Short Run Control Charts
    Publication . Matos, Andreia; Rego, Andreia; Castanheira, Isabel; Matos, Ana Sofia
    This research work presents a study where Statistical Process Control (SPC) is used as an internal quality control tool. SPC was used to monitor and assess the stability of instrumental blank samples for inorganic arsenic analysis through instrumental blank samples used to determine by inductively coupled plasma mass spectrometry (ICP-MS). Control charts allows a simple way to check the accuracy of the analytical methods in a daily routine [1]. Particularly, the Short Run control charts, based on the Quesenberry Q statistics, are very useful when there are not enough data to estimate process parameters or when the sample size is variable in time [2][3]. The use of Short Run control charts joint with process capability analysis revealed to be a suitable tool allowing to detect possible reagent or instrumental contaminations in a daily base. The main purpose of this paper is to develop a joint application using the main SPC concepts, such as control charts and process capability analysis. An intra- and inter-day instrumental blank samples control scheme, using control charts based on Quesenberry Q statistics, was applied to inorganic arsenic to monitor and assess statistical consistence of blank data analysed by ICP-MS [2]. Control charts joint with process capability analysis will constitute a novelty study that will allows to evaluate the in used instrumental LOQ values for inorganic arsenic and establish a new limit.
    2016-10-02Conference object Restricted access Show more
  • Differences in nutritional composition of Shiitake mushrooms (Lentinula Edodes) produced in Portugal
    Publication . Mendes Ribeiro, Mariana; Torres, Duarte; Santos, Mariana; Castanheira, Isabel
    The aim of this study was to evaluate and compare the nutriWonal composiWon of shiitake mushrooms (LenWnula edodes) obtained by different culWvaWon processes from different areas (fruiWng induced by sprinkler from Amarante or dipping method from Sintra). Macronutrient, vitamin B1 and B2, minerals and contaminant trace metals were quanWfied in three samples. Variability among the different samples regarding macronutrients, minerals content was found. Regarding contaminants content, only one sample showed an atypical high value for arsenic. The results obtained indicate that the shiitake mushroom is an important dietary source of several nutrients, and the sample frucWfied by dipping seems to be nutriWonally richer and chemically safer.
    2016-10-02Conference object Restricted access Show more