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Proceeding of the 4 rd International Symposium“NEW RESEARCH IN BIOTECHNOLOGY” USAMV Bucharest, Romania, 2011we analyzed the permeability for gases and water vapors for the bread packagings for theinner-outer and viceversa oxygene transfer and water vapors is linked to the apearance ofseveral alterations of the packed product.The packing layers permeability is the determinant parameter for evaluating theirbarrier properties in the mass transfer (Journal of Food Engineering 89, 2008). For toappreciate a material’s innocuity in direct contact with the food stuff there was determinedthe ceding degree for the different compounds of a package in an extraction liquid.1982. MATERIALS AND METHODSIn order to obtain some available experimental data, wheat flour obtaining fromFLAMURA wheat variety grinding in Chopin Laboratory Mill was used like controlsample. The technological characteristics of flour are shown in Table 1.Moisture%Ash%Table 1. Analytical parameters of Control flourWet gluten%Protein%Hydrationcapacity%FallingNumbersec13.42 0.68 31.1 13,3 62.6 329Buckwheat flour was provided by local producers.The analytical flour quality was determined according to the international standardmethods (ash content – ICC104/1, wet gluten – ICC105/2, protein content – ICC106/2,hydration capacity with Pharinograph - ICC115/1 and Zeleny index – ICC116/1).Like raw material I used also compacted fresh yeast (Saccharomyces cerevisiae)from S.C. ROMPAK, Pascani, with 32.5% dry matter and 46.54% protein content (N x6.25).Dough was prepared using a straight dough method. After baking, the samples werecooling 6-8 hours in controlled atmosphere (UV lamps).In order to be scoring (after 24 hours), and to be examined from microbiologicalpoint of view (after 72 hours), the samples were sliced for packed in plastic bagsMicrobiological quality of bread with buckwheat, over 3 days at room temperaturewas evaluated according with SR EN ISO 4832/2006 quality standard.The mineral substances were evaluated using EDX-900.For the bread packing there were used polypropylene bags (PP), high densitypolyethylene (HDPE), low density polyethylene (LDPE), multilayer foil (PE/ adhesive /PA/ adhesive/ PE) supplied by Sudpack.The determination of the permeability at gases was led according to the BS EN ISO2556/2003 standard, using the Dansensor 1 L 100-5000 device. The determination of thepermeability at water vapors was led according to the SR EN ISO 15106-1/2005 standard,using the Dansensor 1 L 80-5000 device.For the components global determination we used as food simulants distilled water,3% acetic acid and isooctane according to STAS 1186-1/2003. The working method fordetermining the Pb and Cd migration from the plastic materials is similar to the one in SRISO 1: 19997, the exception being made by the acetic acid solution that in our case had a
Proceeding of the 4 rd International Symposium“NEW RESEARCH IN BIOTECHNOLOGY” USAMV Bucharest, Romania, 2011concentration of 3% and the extract was analyzed after the sterilization and concentrationby atomic absorption spectrophotometry in oxyacetylene flame of A Analyst 400 type witha background sound correction.3. RESULTS AND DISCUSSIONSThe analysis of the gases and water vapors permeability of the polyolefin packagingconsisted in the determination of the transmission speed of the gas through thin foils underatmospheric pressure in the case of the gases and the determination of the transmissionspeed of the water vapors for the water vapors permeability.The testing of the permeability of the polyolefin foils underlined the high watervapors and gases barrier of the multilayer foil followed by the PP and HDPE foils. Thelowest barrier properties were presented by the LDPE foil.The migration test conditions in distilled water and acetic acid were: 10 days at40◦C, and for the isooctane 24 hours at 40◦C.No.SampleTable 2. The permeability analysis resultsPermeability at gases(cm 3 /m 2 /day)oxygene CO 2 (23 0 C)(23 0 C),cm 3 /m 2 /day1 PP foil bag 1900 8900 4,212 HDPE foil bag 2123 96000 5,73 LDPE foil bag 6398 36000 25,14 PE multilayer foil bag andwelding layer Surlynionomer and EVOH barrier16 2,7 1Permeability atvapors (g/m 2 /zi)Water vapors(23 0 C)After the evaluation of the global migration level we observed that all the migrationvalues are under the limit of 60 ppm (10mg/dm 2 ), imposed by the laws.After the organoleptic examination and the realization of the extractions in theestablished conditions of the working field the package samples studied destined for foodcontact didn’t present visible changes of the colour and appearance of the surface incomparison with the witness samples. At the same time the food simulants didn’t presentcolour, transparency (opalescence), smell or taste (where possible) changes in comparisonwith the witness samples.The evaluation of the AAS analysis of the heavy metals migration took into accountthe ORD. Nr.975/1998, that specified the limits for: Pb:0,1ppm and Cd absent. Weobserved that most of the values were under the LD detection limit of the device, with twoexceptions in the case of Pb (the PP and LDPE foils).The analysis of the technological and physico-chemical quality of the bread packedin polyolefin packageFor evaluating the quality of the bread with buckwheat adding we made two samplesone with high gluten wheat flour and one with 10% Buckwheat flour adding.199
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