ارزیابی ویژگی‌های فیلم‌های هوشمند حساس به ph بر پایه نشاسته/کتیرا و آنتوسیانین گیاه پنیرک

زمینه مطالعاتی : فیلم های رنگ سنجی زیست تخریب پذیر حاوی آنتوسیانین های عصاره های گیاهی می تواند یک پیشرفت جدید در زمینه بسته بندی مواد غذایی باشند. هدف: هدف از این پژوهش تهیه نوعی بسته بندی هوشمند حساس به ph بر پایه پلیمرهای طبیعی نشاسته/صمغ کتیرا به عنوان یک ماتریکس جامد و آنتوسیانین های گیاه پنیر (malva sylvestris) به عنوان نشانگر حساس به ph می باشد. روش کار: ابتدا آنتوسیانین موجود در گلبرگ گیاه پنیر به روش غوطه وری (اتانو ل و اسید) استخراج شد. سپس فیلم های هوشمند بر پایه نشاسته/کتیرا حاوی آنتوسیانین های پنیرک با استفاده از روش قالب ریزی تهیه شد. در نهایت ویژگی های ساختاری، فیزیکی، مکانیکی و پاسخ های رنگی به تغییرات ph و گاز آمونیاک فیلم ها مورد بررسی قرار گرفت. نتایج: حلالیت و رطوبت در فیلم های حاوی آنتوسیانین به شکل معنی داری کمتر از فیلم نشاسته/صمغ کتیرا می باشد. میزان نفوذپذیری به بخارآب فیلم ها با افزایش غلظت آنتوسیانین افزایش یافت. همچنین مقاومت کششی فیلم ها با اضافه شدن آنتوسیانین به فیلم کاهش یافته و کمترین مقاومت در فیلم حاوی 2 درصد آنتوسیانین مشاهده شد. فیلم های تهیه شده نسبت به تغییرات ph حساس بوده و در عرض کمتر از 5ثانیه تغییر رنگ نشان دادند. رنگ فیلم های حاوی عصاره در شرایط اسیدی، خنثی و قلیایی به ترتیب صورتی، بنفش و سبز گردید. همچنین فیلم های نشانگر حاوی 0/5 و 1 درصد عصاره آنتوسیانین، در غلظت های 0/8 و 1/4 مولار آمونیاک حساسیت بالایی به بخار آمونیاک نشان داده به طوری که تغییر رنگ بعد از 20 دقیقه مشاهده گردید. نتیجه گیری نهایی: فیلم هوشمند حاوی عصاره پنیر قابلیت کاربرد به عنوان فیلم های نشانگر تازگی/فساد را دارا می باشد.

properties evaluation of ph-sensitive films based on starch/tragacanth and common mallow (malva sylvestris) anthocyanins

introduction: in recent years, researchers have focused on production of active and smart packaging due to the increasing interest of consumers in biodegradable packaging smart films are a category of biodegradable films that convey visual information to consumers anthocyanins are a group of flavonoids that are responsible for the red, blue and purple colors of plants the color of anthocyanins changes in different ph malva sylvestris is a violet-petalled plant with a wide range of antioxidant, anti-inflammatory, anti-carcinogenic, and antimicrobial activities, which is native to europe, north africa, and southeast asia (particularly iran) numerous studies have been conducted on the phytochemicals present in this plant, and it has been found to contain substantial quantities of anthocyanins, flavone, flavonols, naphthoquinone, various monoterpenes, niacin, and folic acid the use of anthocyanins from different plants in combination with biopolymers has attracted increasing interest in the food industry the replacement of non-biodegradable fossil-based packaging by biodegradable materials or from renewable sources can lead to reduced environmental impact one of these biopolymers is starch starch is one of the most important polysaccharides, which is used in the production of biodegradable films due to its good film-forming ability, ease of production, renewable resources, and low price however, like other natural polymers, it has films with low mechanical and thermal resistance, especially in conditions of high relative humidity in recent years, many studies have been conducted to improve the characteristics of films made from natural polymers one of the ways to strengthen the characteristics of biopolymer films is to combine natural polymers with each other and form a composite tragacanth, also known as tragacanth gum in the world, is the most important product of the tragacanth plant tragacanth gum has a good stability against acids gum tragacanth is usually hydrated in water at a low concentration and forms a gel at a concentration of 2 to 4% also, tragacanth gum has a long storage life without reducing viscosity compared to other hydrocolloids in addition to this, past studies have proven that tragacanth gum has the ability to form a film the purpose of this research is to prepare a kind of smart packaging sensitive to ph based on natural polymers of starch/tragacanth as a solid matrix and anthocyanins of malva sylvestris plant as a ph sensitive indicator. material and methods: first, the anthocyanin in the petals of malva sylvestris was extracted by immersion method (ethanol and acid) then, smart film based on starch/tragacanth containing malva sylvestris extract was produced by casting method finally, the effect of addition of malva sylvestris extract on the structural (ft-ir, xrd, sem), physical (moisture, water solubility, wvp), mechanical (ts and elongation at break) properties, color, sensitivity to ph and ammonia of starch/tragacanth films were investigated. results and discussion: results showed that the moisture content and water solubility were significantly lower in the films containing anthocyanins than control starch/tragacanth film wvp of films were decreased with increasing the anthocyanins concentration the ts of films were decreased with addition of anthocyanins and lowest ts were observed in the films containing 2% anthocyanins the extracted anthocyanins were sensitive to the ph changes and lower 5 s the color change was observed the color of films were pink, purple and green at acidic, neutral and alkaline, respectively furthermore, the films containing 0.5 and 1% anthocyanin extract were sensitive to the 0.8 and 1.4 m ammonia and after 20 min the color change were observed. conclusion: this result showed that smart films containing malva sylvestris anthocyanins extract has the potential to be used as films indicating freshness/corruption.