مدل سازي انتقال ديمتيل ترفتالات از ظروف پلي اتيلن به درون نوشابه هاي گازدار

ظروف پلي اتيلن ترفتالات (PET) به دليل شفافيت بالا، قابليت انعطاف مناسب، مقاومت كافي و ممانعت از خروج گاز به منظور بسته بندي مواد غذايي مورد توجه كارخانجات مواد غذايي قرار دارند. عليرغم مزيت هاي پرشمار، اين محصول معايبي نيز دارد كه يكي از مهمترين آنها انتشار مواد از ظرف به مواد داخل آن مي باشد. در اين تحقيق تاثير دو عامل زمان و دماي نگهداري بر روي ميزان مهاجرت ارزيابي و مدلسازي شد. به منظور طراحي آزمايشات از روش سطح پاسخ (RSM) استفاده شد. در ابتدا نوع مواد مهاجر و شرايط موثر در مهاجرت مواد از ظروف پلي اتيلن ترفتالات به نوشابه شناسايي و بررسي شد. نتايج بيانگر آن بود كه دو عامل زمان در تماس بودن نوشابه با ظرف و دماي محيط نگهداري تاثير فراواني بر روي ميزان مهاجرت پلي اتيلن ترفتالات به داخل نوشابه دارند. پس از مطالعات ابتدايي توسط روش اسپكتروفوتومتري ميزان تركيبات انتقال يافته به دروننوشابه سنجش شده و اين نتايج به كمك روش سطح پاسخ مدل سازي شدند. نتايج به دست آمده نشان داد كه مي توان ارتباط ميان ميزان انتقال مواد، دما و زمان را به صورت يك مدل تواني مدل سازي كرد. همچنين توسط مدل بدست آمده مي توان عنوان كرد كه دما و مدت زمان ماندگاري به ترتيب و به صورت مستقيم با نسبت هاي 0/003 و 1/17 روي ميزان انتقال تاثير مي گذارند.

Background & objectives: Polyethylene terephthalate (PET) containers have many applications in the food industry. Although there are numerous advantages for PET it also has some disadvantages, one of which is the migration of materials from the container into the material inside. In this study, the effect of two factors of storage time and temperature on the migration rate was evaluated and modeled. Methods: To design the experiments, the surface-response method (RSM) was used. First, the type of migratory material and the effective conditions on the migration of materials from polyethylene terephthalate containers to soft drinks were identified and investigated. The primary results showed that the two factors of time of contact of the beverage with the container and the temperature of the storage environment have a significant effect on the migration of polyethylene terephthalate into the beverage. After the initial studies, the amount of compounds transferred into the beverage was measured by the spectrophotometric method and these results were modeled using the level-response method. Results: The results showed that the association between material transfer rate, temperature, and time can be modeled as a two-dimensional power model. It can also be stated by the model that temperature and shelf life directly affect the transfer rate with ratios of 0.003 and 1.17, respectively. The rate of migration is directly related to the square of the storage time and the temperature of the storage environment. The shelf life of the beverage has a very high impact on the migration rate, and mathematically the migration rate can be considered as a function of the shelf life of the soft drink. In addition to the shelf life of the beverage storage temperature is also a very important factor in the migration rate and the combination of the two can increase the rate of migration exponentially. Conclusion: Polyethylene terephthalate containers are not suitable for storing non-alcoholic carbonated beverages and have the potential to cause harm to consumer health.