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- Measurement of oxygen transmission rate through foamed materials for bottle closuresPublication . Poças, Maria F.; Ferreira, Belmiro; Pereira, Joel; Hogg, TimThe determination of the oxygen transmission rate (OTR) through closures in glass bottles is becoming increasingly important for quality control of different batches and for development purposes. The Mocon method for measuring OTR is globally accepted and used in different applications. However, one of the major drawbacks this method presents when applied to bottle/closures systems is the long time required to obtain stable measurements when 40 mm long closures are tested. This paper describes a method to obtain OTR values with samples of reduced thickness with much shorter measurements time, since the condition of steady state during measurements is achieved faster and compares the estimated full-length commercial closure OTR with experimental values
- Safety evaluation of the food enzyme α-amylase from a genetically modified Aspergillus niger (strain NZYM-SB)Publication . EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Poças, Maria de Fátima TavaresThe food enzyme is an α-amylase (4-α-d-glucan glucanohydrolase; EC 3.2.1.1), produced with the genetically modified Aspergillus niger strain NZYM-SB by Novozymes A/S. The food enzyme does not contain the production organism or its DNA; therefore, there is no safety concern for the environment. The α-amylase is intended for use in starch processing, beverage alcohol (distilling) processes and baking processes. Residual amounts of total organic solids (TOS) are removed by distillation and by the purification steps applied during the production of glucose syrups (by > 99%). Consequently, dietary exposure was not calculated for these two uses. Based on the maximum use levels recommended for the baking processes and individual consumption data from the EFSA Comprehensive European Food Consumption Database, dietary exposure to the food enzyme–TOS was estimated to be up to 3.075 mg TOS/kg body weight per day in European populations. The food enzyme did not induce gene mutations in bacteria or micronuclei in human lymphocytes. Subchronic toxicity was assessed by means of a repeated-dose 90-day oral toxicity study in rodents. A no observed adverse effect level (NOAEL) was derived that, compared with the dietary exposure, resulted in a sufficiently high margin of exposure (MOE). Similarity of the amino acid sequence to those of known allergens was searched and two matches were found. The Panel considered that the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded, but the likelihood is considered low. Based on the genetic modifications, the manufacturing process, the compositional and biochemical data, the findings in the toxicological and genotoxicity studies, as well as the estimated dietary exposure, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.
- Exposure assessment of chemicals from packaging materials in foods: reviewPublication . Poças, Maria de Fátima; Hogg, TimIt is recognised that chemicals from packaging and other foodcontact materials can migrate into the food itself and thus be ingested by the consumer. The monitoring of this migration has become an integral part of ensuring food safety. This article reviews the current knowledge on the food safety hazards associated with packaging materials together with the methodologies used in the assessment of consumer exposure to these hazards. Special attention is given to the most promising approaches for exposure assessment and to the technical and other barriers which need addressing.
- An overview of hazards and risks in food contact materialsPublication . Poças, M. F.; Hogg, T.
- Safety evaluation of the food enzyme endo-1,4-β-xylanase from a genetically modified Aspergillus niger (strain XEA)Publication . EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Poças, Maria de Fátima TavaresThe food enzyme is an endo-1,4-β-xylanase (EC 3.2.1.8) produced with a genetically modified strain of Aspergillus niger (strain XEA), by DSM Food Specialities B.V. The food enzyme is intended to be used in baking and brewing processes. Based on maximum use levels recommended for the food processes and individual consumption data from the EFSA Comprehensive European Food Consumption Database, dietary exposure to the food enzyme–total organic solids (TOS) was estimated to be up to 0.310 mg TOS/kg body weight per day in European populations. Genotoxicity tests with the food enzyme did not indicate a genotoxic concern. A repeated dose 90-day oral toxicity study in rodents, carried out with this endo-1,4-β-xylanase, showed no concern with respect to systemic toxicity. The allergenicity was evaluated by searching for similarity of the amino acid sequence to those of known allergens; no match was found. The Panel considers that there are no indications for allergic sensitisation and elicitation reactions by dietary exposure to the food enzyme endo-1,4-β-xylanase. Based on the microbial source, the genetic modifications performed, the manufacturing process, the compositional and biochemical data provided, the dietary exposure assessment, the findings in the toxicological studies and the allergenicity assessment, the Panel concludes that this food enzyme does not give rise to safety concerns under the intended conditions of use.
- Legislação e RegulamentaçãoPublication . Selbourne, Maria do Céu; Poças, Maria de Fátima
- Phytochemicals preservation in strawberry as affected by pH modulationPublication . Oliveira, Ana; Gomes, Maria Helena; Alexandre, Elisabete M. C.; Poças, Fátima; Almeida, Domingos P. F.; Pintado, ManuelaStrawberries purees are incorporated in foods and subjected to pH modulation according to the expected final food matrix. The effect of pH on strawberry polyphenols stored at 4 and 23 degrees C for 90 days was evaluated. Total antioxidant activity and total phenolics content were only affected by time according to a first order model. The pH 4.5 induced higher decrease in (-)-epigallocatechin gallate (71% and 79%) and quercetin-3-glucoside (29% and 36%), for both storage temperatures. For pH 2.5 and 3.0, ellagic acid increased 84% for 4 degrees C. and 185% for 23 degrees C. Anthocyanins concentration changes along storage were well described by first order model. The pH value of 2.5 presented the lower kinetic constant rate where cyanidin-3-glucoside, pelargonidin-3-glucoside and pelargonidin-3-rutinoside had a k = 0.04, 0.05 and 0.03 day(-1). Lower storage temperature (4 degrees C) and lower pH (2.5) were the best condition for the preservation of polyphenols in pasteurized strawberry during a 90-day storage period.
- Features and performance of edible films, obtained from whey protein isolate formulated with antimicrobial compoundsPublication . Ramos, Óscar L.; Silva, Sara I.; Soares, José C.; Fernandes, João C.; Poças, M. Fátima; Pintado, Manuela E.; Malcata, F. XavierThe goal of this research effort was to assess the efficacy of edible films produced fromwhey protein isolate (WPI) and glycerol, including incorporation of lactic acid (LA) and propionic acid (PRO), chitooligosaccharideswith nominal MW of 3 kDa (COS) and natamycin (NA) as antimicrobial agents. Their features were evaluated in vitro via agar diffusion and viable cell counting, against spoilage microflora often found contaminating cheese surfaces. The effect of incorporating the aforementioned compounds upon thickness, moisture content (MC), solubility (S), density (ρs),water activity (aw) and water vapor permeability (WVP), as well as upon tensile and optical properties of those films were also evaluated. Films formulated with LA, PRO or COS exhibited antimicrobial activity against all microorganisms tested, yet the viable cell count assay was more sensitive and reproducible. COS was the most active against Gram-negative bacteria, whereas LA was the most active against Gram-positive ones. NA was not active against bacteria, but displayed the strongest effect against yeasts. Incorporation of said antimicrobial compounds did not significantly (pN0.05) affect film thickness, yet it significantly (pb0.05) reduced tensile strength (TS). Incorporation of LA and NA in particular did not significantly (pb0.05) affect MC, S, ρs, WVP, elongation at break (EB) and Young's modulus (YM) values; however, a statistically significant increase (pb0.05) of MC, S andWVP, together with a statistically significant decrease (pb0.05) of ρs were attained upon incorporation of PRO or COS. Moreover, PRO produced the highest variation (pb0.05) in EB, TS and YM,whereas COS produced the highest change (pb0.05) in optical properties.
- Embalagens activas e inteligentes: promessas à vistaPublication . Poças, Fátima; Delgado, Telma
- Safety assessment of the active substances carboxymethylcellulose, acetylated distarch phosphate, bentonite, boric acid and aluminium sulfate, for use in active food contact materialsPublication . EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Poças, Maria de Fátima TavaresThis scientific opinion of the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF Panel) deals with the safety evaluation of the active substances carboxymethylcellulose, acetylated distarch phosphate (FCM substance No 1071), bentonite, boric acid and aluminium sulfate (FCM substance No 1072). The mixture is intended to be used as a liquid absorber in the packaging of perishable foods to extend their shelf-life. All substances have been evaluated and approved for use as additives in plastic food contact materials and/or as food additives. Migration of boron into foods was up to 0.7 mg/kg food. Migration of aluminium was not detected (limit of detection (LOD) of 0.001 mg/kg). The CEF Panel concludes that the substances carboxymethylcellulose, acetylated distarch phosphate, bentonite, boric acid and aluminium sulfate are not of safety concern for the consumer when used as active components in moisture and liquid absorbers. The absorbent pads must be used under conditions in which direct contact between the active mixture and the food is avoided and the fluid absorption capacity of the absorber is not exceeded.