استخراج و آنالیزکیفی‏ ژلاتین پای مرغ و بررسی تاثیر آن بر خواص فیزیکوشیمیایی مارشمالو

مارشمالو یک فرآورده‌ی قنادی هوادهی شده است که در تهیه آن عمدتاً از ژلاتین (به‌عنوان عامل کف‌کننده و ژل‌کننده)، محلول قندی (شامل شربت گلوکز و شکر)، طعم‌دهنده و رنگ‌دهنده استفاده می‌شود. ژلاتین‌ها درشت ملکول‌های آمفیدوست هستند و از هیدرولیزکلاژن‌ها به‌دست ‏می‏‌آیند. ژلاتین یک پروتئین کاملاً قابل هضم است و حاوی تمام اسیدهای آمینه ضروری به جز تریپتوفان است. در این پژوهش ژلاتین پای مرغ به روش اسیدی استخراج شد و در محصول مارشمالو با دو سطح 6 و 8 درصد مورد استفاده قرار گرفت. در آنالیز فیزیکوشیمیایی ژلاتین استخراجی از پای مرغ، میزان پروتئین 78.27±0.445، چربی 2±10، خاکستر 47.6±0.46 و رطوبت 70.12±0.28 درصد بود. در آزمون روبش فرکانس، مدول ذخیره همواره بالاتر از مدول افت بود که حاکی از استحکام بالا و رفتار ویسکوالاستیک ژلاتین در کرنش معین می‌باشد. افزودن 8 درصد ژلاتین به نمونه مارشمالو شاخص‌های سختی، صمغیت، چسبندگی در بافت را به‌طور معنی‏‌داری افزایش داد. بین نمونه‌ها در شاخص‌های رطوبت، فعالیت آبی و شاخص a,b رنگ اختلاف معنادار وجود نداشت. از نظر پارامترهای حسی شیرینی، سفتی بافت، صمغیت و پذیرش کلی به نمونه 8 درصد ژلاتین کمترین امتیاز اعطا شد. در محدوده  فرکانس اعمال شده مدول g’ در تما‏می‏ نمونه‏‌ها بالاتر از مدول g& بود که بر رفتار ویسکوالاستیک و قوی‏ بودن ژل در کرنش معین دلالت داشت. مارشمالوی متشکل از 6 درصد ژلاتین از نظر خواص فیزیکوشیمیایی، رئولوژیکی و ارزیابی حسی به‏‌عنوان فرمولاسیون منتخب تعیین گردید. با استناد به نتایج به‌دست‌آمده از این پژوهش این نوآروی می‌‏تواند در جهت تولید محصولات سلامت محور و مقرون به‌صرفه در صنعت مواد غذایی کشور به‌کار گرفته شود.

extraction and qualitative analysis of chicken feet gelatin and investigating its effect on the physical and chemical properties of marshmallow

introductionfoams are colloidal systems that are formed by the accumulation of gas bubbles separated from each other by thin liquid layers. foams have attracted a lot of attention from the food industry and culinary arts due to their unique flavor and texture properties. marshmallows are an aerated confectionery product that is mainly prepared from gelatin (as a foaming and gelling agent), sugar solution (including glucose syrup and sugar), flavoring, and coloring agents. gelatins are amphiphilic macromolecules and are obtained from hydrolyzed collagens. gelatin is a quite digestible protein and contains all essential amino acids except tryptophan. the simplest way to produce gelatin is to convert collagen into gelatin by denaturing or breaking down the collagen molecule to make it soluble in water. this process generally involves an acidic, alkaline, or enzymatic pretreatment. in food applications, gelatin can act as a foaming agent, emulsifier, biodegradable film former, colloidal stabilizer, and microencapsulating agent. due to health, religious, and economic restrictions on the consumption of gelatin from mammals, other sources for gelatin production must have characteristics such as high amounts of by-product availability (because continuous production in the industry is an essential economic issue) and a value close to the rheological properties of mammalian gelatin in order to be considered as a alternative suitable source for replacement. hence, poultry by-products can be investigated as a new source of gelatin extraction. materials and methodsin this study, gelatin was extracted, from chicken feet using an acidic method. the gelatin production process consists of three main steps: pretreatment of raw materials, gelatin extraction, purification, and drying. gelatin of chicken feet was used in the marshmallow product at two levels of 6 and 8 percent. physicochemical properties of gelatin including moisture, color, gel strength, rheology, fat, protein, and ash were analyzed. in the evaluation of the marshmallow, textural components, rheology, electron microscopy, differential thermal scanning, and sensory evaluation (appearance, color, aroma, sweetness, texture, hardness, and gumminess) were determined. the sensory evaluation was conducted on a five-point hedonic scale. statistical analysis of this study was performed with duncan’s multiple range test using spss software. result and discussion in the physicochemical analysis of gelatin extracted from chicken feet, the protein content was 78.27±0.445, fat 10±2, ash 47.6±0.46 and moisture 70.12±0.28%. in the frequency sweep test, the storage modulus was always higher than the loss modulus, indicating the high strength and viscoelastic behavior of gelatin at a given strain. in evaluating the flow behavior of gelatin obtained from chicken feet, the viscosity of the sample decreased with increasing shear rate, indicating the shear-thinning behavior of gelatin. adding 8% gelatin to the marshmallow sample significantly increased the hardness, gumminess, and texture adhesion indices. the overran in the sample contained 8% gelatin was 40, and the marshmallow contained 6% gelatin was 30. the presence of more protein has a positive effect on the process of reducing surface tension, and more proteins, with the polar parts of the molecule is opened towards the water, are absorbed at the interface, creating a stabilizing layer around the bubbles, which causes more foam to form and increases overran. there was no significant difference between the samples in moisture, water activity, and color a, b indices. in terms of sensory parameters of sweetness, texture firmness, gumminess, and overall acceptance, the 8% gelatin sample was given the lowest score. in the applied frequency range, the g’ modulus in all samples was higher than the g& modulus, indicating viscoelastic behavior and gel strength at a definite strain. in all samples, the complex viscosity decreases linearly with increasing applied frequency, reflecting the shear-thinning behavior of the samples. marshmallow consisting of 6% gelatin was determined as the selected formulation in terms of physicochemical, rheological, and sensory evaluation properties. conclusionbased on the results obtained from this research and in order to optimally utilize chicken waste, this innovation can be used to produce health-oriented and cost-effective product.