l. darabi
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تاثیر پوشش پروتیینی پر هیدرولیز شده بر کیفیت داخلی تخم مرغ در طول دوره نگهداری به مدت چهار هفته و در دمای اتاق بررسی شد. صد و بیست عدد تخم مرغ از سویه Hy-Line W36 در قالب طرح کاملا تصادفی به سه تیمار اختصاص داده شدند. تخم مرغ ها شماره گذاری شده و برای هر تیمار، 40 عدد تخم بر اساس وزن به صورت صعودی در دسته های سه تایی مرتب شدند. تیمارها شامل تیمار شاهد (بدون پوشش)، پوشش پروتیینی حاوی 10 درصد پر هیدرولیز شده (وزنی/ حجمی) و پوشش پروتیینی حاوی 20 درصد پر هیدرولیز شده بودند. صفات کیفی شامل وزن تخم مرغ، واحد هاو، وزن سفیده، وزن زرده، رنگ زرده، pH سفیده، pH زرده، استحکام پوسته، در هشت تخم مرغ از هر تیمار در نمونه تازه و نمونه های پس از یک، دو، سه و چهار هفته نگهداری اندازه گیری شدند. نتایج این آزمایش نشان داد که ارتفاع سفیده و واحد هاو در گروه دارای پوشش 20 درصد پر هیدرولیز شده نسبت به سایر گروه ها در تمام طول دوره نگهداری به طور معنی داری بالاتر بود (05/0<p). درجه کیفی تخم مرغ و pH سفیده به ترتیب دارای بالاترین و پایینترین میزان در گروه دارای پوشش 20 درصد پر هیدرولیز شده طی هفته های اول و سوم بودند (05/0<p). کمترین درصد افت وزن در طول آزمایش مربوط به تخم مرغهای دارای پوشش 10 درصد پر هیدرولیز شده بود (05/0<p). بر اساس نتایج این آزمایش به نظر می رسد که استفاده از پوششها در طول دوره نگهداری تخم مرغ می تواند سبب افزایش ماندگاری با حفظ کیفیت تخم مرغ شود.
کلید واژگان: پر هیدرولیز شده، پوشش پروتئینی، تخم مرغ، دوره نگهداریIntroductionEgg is one of the most valuable food items in the human diet. Several factors, such as diseases, bird age, diet, temperature, humidity, transportation, and storage time can affect the quality of eggs. The longer the storage time, the more CO2 penetrates the eggshell, particularly at room temperature, resulting in decreased internal quality. Eggs are a perishable product and must be stored in the refrigerator from production to consumption. Refrigeration increases production costs and ultimately leads to an increase in the final product price. Currently, there is a growing interest in developing effective methods to preserve the internal quality of eggs. The use of edible coatings after washing the eggs can help preserve the internal quality of the eggs during long-term storage. Edible coatings are an available technology that is currently used to control moisture, gas exchange, and oxidation processes for many products. The use of suitable active and antimicrobial edible films and coatings can potentially reduce the microbial load of egg surfaces, reduce undesirable changes, and increase their shelf life. Proteins are commonly used as film-forming materials. Proteins that have been previously investigated for egg coating development include whey protein isolate or concentrate, zein, and rice protein concentrate. Chicken feathers are a by-product of the poultry industry and are mostly disposed of without any processing, causing severe environmental pollution. To date, hydrolyzed feather protein has not been reported as an egg coating, so this study investigated the effect of hydrolyzed feather protein coating at two concentrations on the shelf life of chicken eggs under room temperature storage conditions.
Materials and methodsIn this study, a total of 120 fresh white-shelled eggs were obtained from Hy-Line W36 laying hens. The eggshells were washed to remove any surface contamination, then the eggs were numbered and randomly selected for each coating method. The samples were divided into three treatments of 40 eggs each treatment in a completely randomized design. The treatments included control (0%, without coating), a coating containing 10% (w/v) hydrolyzed feather, and a coating containing 20% hydrolyzed feather. Pure glycerol (Serva, Germany) was added to hydrolyzed feathers (2% w/v). The feather hydrolyzed protein was prepared at Tarbiat Modares University using alkaline hydrolyzed raw chicken feathers obtained from a commercial broiler slaughterhouse (Iran Borchin, Tehran). The chemical analysis of hydrolyzed feather protein was performed based on standard methods (dry matter, protein, ash, and fat), and the amino acid profile of the protein was also tested. Some nutritional or toxic important minerals were also measured. Egg weight, Haugh units, albumen weight, yolk weight, yolk color, albumen pH, yolk pH, and shell strength were measured during storage weeks 0, 1, 2, 3, and 4.
Results and discussionAccording to the data of this study, the height of the egg white and Haugh units in the stored eggs were significantly affected by the experimental coatings (P<0.05). The height of the egg white and Haugh units were significantly higher in the treatment with 20% hydrolyzed protein coating compared to other treatments (P<0.05). The yellowness of the egg yolk was significantly affected by the experimental coatings in the third week (P<0.05). The highest egg quality score was observed in the first and third weeks in eggs with 20% hydrolyzed feather protein coating (P<0.05). The eggshell characteristics were not affected by the experimental coatings. The egg white and yolk percentages were not affected by the experimental coatings. The pH of the egg white in the first and third weeks decreased significantly in eggs with 20% hydrolyzed feather protein coating compared to other treatments (P<0.05). The pH of the yolk was not affected by the experimental treatments. The pH in both the yolk and egg white increased over time. Eggs with coating had significantly less weight loss compared to uncoated eggs (P<0.05). The lowest weight loss was related to eggs with 10% and 20% hydrolyzed feather protein coating, which had a significant difference with uncoated eggs (P<0.05). The weight loss after seven days of storage in uncoated eggs (2.12%) was almost double the weight loss in coated eggs (1.16%). The weight loss after 14 days of storage at room temperature in uncoated eggs (4.21%) was almost double the weight loss in coated eggs (2.35%). The weight loss after 21 days of storage at room temperature in uncoated eggs (6.8%) was almost double the weight loss in coated eggs (3.35%). The weight loss after 28 days of storage at room temperature in uncoated eggs (8.27%) was almost double the weight loss in coated eggs (4.80%). Based on the results of this study, it was found that the use of hydrolyzed feather protein coating can improve the internal quality of eggs during the storage period. For future research, it is recommended to conduct further studies on the effect of hydrolyzed feather protein coating on the quality characteristics of eggs during storage. Previous studies have been conducted on improving the internal quality of eggs during storage using protein coatings with different hydrolysis. Some of these studies have shown that protein coating with hydrolysis can significantly improve the quality characteristics of eggs. Additionally, some studies have been conducted on the effect of protein coating using different proteins such as rice protein, meat protein, whey protein isolated, or whey protein concentrate and zein.
ConclusionsThere was no significant difference in weight loss between 10% and 20% hydrolyzed feather protein coverage in different weeks, but the 10% hydrolyzed feather protein coverage provided better protection against weight loss. Since weight loss is mainly due to eggshell water evaporation, it was observed that despite being thinner, the 10% hydrolyzed feather protein coverage provided better protection compared to the 20% hydrolyzed feather protein coverage. Therefore, the use of coverages during egg storage can increase shelf life while maintaining egg quality.
Keywords: Hydrolyzed feather, protein coating, egg, Storage period -
مقدمه
یکی از شایع ترین علل ناتوانی در مناطق دنیا و ایران، شکستگی های ناشی از بیماری استئوپورز است که شیوع آن در زنان و افراد سالمند بیشتر می باشد. بنا بر این پیشگیری از پوکی استخوان و شکستگی های ناشی از آن هدف عمده بسیاری از مراقبت های بهداشتی بوده است. این پژوهش با هدف ارزشیابی تاثیر آموزش بر آگاهی دانش آموزان دختر دوره راهنمایی(پایه های اول تا سوم) در خصوص استئوپورز انجام گردید.
مواد و روش هاروش بررسی یک مطالعه تجربی از نوع آزمون-شاهد، روی 214 نفر از دانش آموزان دختر مقطع اول، دوم و سوم راهنمایی شهر اندیشه استان تهران که به روش نمونه گیری تصادفی وارد مطالعه شدند، انجام گرفت.(گروه آزمون 111 نفر و گروه شاهد 103 نفر) داده ها با استفاده از پرسش نامه استاندارد(روایی و پایایی) که شامل 9 سوال دموگرافیک و 24 سوال مربوط به آگاهی در مورد استئوپورز بود جمع آوری شد. پس از آزمون اولیه یک جلسه مداخله آموزشی در گروه آزمون انجام شد و 2 هفته بعد دانش آموزان پیگیری شدند. داده های تحقیق با استفاده از نرم افزار آماری SPSS vol.16 و آزمون های آماری(t مستقل، t زوجی، من ویتنی و ویلکاکسون) مورد تجزیه و تحلیل قرار گرفت. مشارکت افراد در این تحقیق داوطلبانه و با رضایت آگاهانه بود.
یافته های پژوهش: میانگین نمره آگاهی افراد در گروه آزمون و شاهد، قبل از مداخله تفاوت معنی داری نداشت ولی پس از مداخله تفاوت معنی داری مشاهده گردید.(P<0.001) هم چنین بین میانگین نمره آگاهی افراد تحت بررسی در پایه های اول، دوم و سوم در دو گروه آزمون و شاهد، پس از مداخله تفاوت معنی دار وجود داشت.(P<0.001)بحث و نتیجه گیریبا توجه به یافته های این مطالعه و نظر به این که سطح آگاهی دانش آموزان در مورد پوکی استخوان بسیار محدود بود ضرورت جدی برای طراحی مداخلات آموزشی در مدارس مورد مطالعه وجود دارد که استفاده از شیوه های بسیار کم هزینه و موثر آموزشی می تواند در راستای ارتقاء آگاهی های آن ها بسیار کمک کننده باشد
کلید واژگان: آگاهی، استئوپورز، مداخله آموزشی، دانش آموزانIntroductionOsteoporosis-related fractures are one of the most common causes of disabilities in the world as well as in Iran that their incidence is more common among women and old persons. Considering the importance of preventing osteoporosis، especially in women، this study was performed to determine the effect of brief osteoporosis education on knowledge of the first، second and third grades middle school girl students. Methods & Materials: This experimental study (case-control design) was carried out in 2012. The convenience sample included 214 students (the first، second and third grades) were randomly divided to case (111) and control (103) groups. The data collection tools were standard questionnaires that 2 times (before and 2 weeks after education) were completed by the students under study. After pre-test، 1 educational session in the case group were performed. Finally، the data were analyzed by SPSS 16 software and statistical tests (independent t-test، paired t-test، Mann-Whitney and etc). Participation of students was voluntary and with informed consent.
FindingsResults of the study showed that there were no significant differences between the scores of knowledge in two groups before the intervention; however، after the intervention there was a significant difference in the levels of knowledge between the case and control groups (p<0. 001). The same situation was observed in comparing students of grade 1، 2، and 3 between the two groups، separately. Discussion &
ConclusionAccording to the results، it could be concluded that the brief program was effective on increasing knowledge of the students who had limited information. Thus، short effective interventions but with low costs could be very helpful in improving the awareness of students on osteoporosis and other similar problems.
Keywords: knowledge, osteoporosis, education, students
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