مقایسه اثر نیتریت سدیم و نانوکپسول‌های حامل آستاگزانتین میکروجلبک هماتوکوکوس (haematococcus pluvialis) با پوشش ترکیبی مالتودکسترین-کازئینات سدیم در کنترل فساد اکسیداتیو و میکروبی سوسیس معمولی

هدف تحقیق حاضر امکان سنجی جایگزینی نیتریت سدیم در فرمولاسیون سوسیس معمولی با استفاده از نانوکپسول های حامل آستاگزانتین بود تا از این طریق از مضرات سوسیس کاسته و به ارزش غذایی آن افزوده شود. به‌همین منظور پس از استخراج رنگدانه آستاگزانتین از میکروجلبک هماتوکوکوس پلوویالیس با استفاده از تکنیک اسید-استون و نانو ریزپوشانی آن با پوشش ترکیبی مالتودکسترین-کازئینات سدیم، نانوکپسول های حامل با نسبت های مختلف، جایگزین نیتریت سدیم در فرمولاسیون سوسیس معمولی شدند و تیمارهای حاصل از نظر اکسیداسیون، فساد میکروبی، شاخص های رنگی و خواص حسی طی 28 روز نگهداری در دمای یخچال مورد ارزیابی قرار گرفتند. نتایج نشان داد اثرگذاری نانوکپسول های حامل آستاگزانتین در زمینه کنترل دو شاخص فساد اکسیداسیونی یعنی تیوباربیتوریک اسید و عدد پراکسید به‌صورت معنی داری بیشتر از نیتریت سدیم است (0/05>p) و کمترین حد این دو شاخص در تیمارهای دارای بیشترین میزان نانوکپسول های حامل ثبت شد. عکس این نتیجه در مورد بازهای ازته فرار و ph مشاهده شد؛ به این صورت که قدرت نیتریت سدیم در کنترل این دو شاخص به‌صورت قابل ملاحظه ای بیشتر از نانوکپسول های حامل آستاگزانتین بود (0/05>p). مطابق یافته ها، وقتی 30 تا mg/kg 60 از mg/kg 120 حد مجاز نیتریت سدیم در فرمولاسیون سوسیس با نانوکپسول های حامل آستاگزانتین جایگزین شد، تیمارهای حاصل از نظر میزان و روند بازهای ازته فرار و ph طی دوره نگهداری با تیماری که صرفا حاوی mg/kg 120 نیتریت سدیم است، فاقد اختلاف معنی دار بودند (0/05p). بنابر یافته های تحقیق حاضر، نانوکپسول های حامل آستاگزانتین پتانسیل مطلوبی جهت جایگزینی نیتریت سدیم در فرمولاسیون سوسیس دارند.

comparison of the effect of sodium nitrite and nanocapsules carrying astaxanthin from haematococcus pluvialis with maltodextrin-sodium caseinate combined coating in controlling oxidative and microbial spoilage of common sausage

introductionone of the synthetic and harmful preservatives used in sausage formulation is sodium nitrite. this compound helps to increase the shelf life and marketability of meat products by preventing the growth of anaerobic bacteria, especially clostridium, exerting an antioxidant effect, stabilizing the red color of meat and improving the taste. despite these benefits, sodium nitrite is very dangerous for health and it can cause malignant diseases. for this reason, it is necessary to replace this substance using a natural preservative. pigments extracted from aquatics such as astaxanthin due to having antioxidant activity, antimicrobial properties and pink color may be a good substitute for sodium nitrite. however, these pigments must be nanoencapsulated at first due to their sensitivity to food processing conditions, including high temperatures. the aim of the current research at the first was to extract astaxanthin from haematococcus pluvialis microalgae using the acid-acetone method and pigment nanoencapsulation using maltodextrin-sodium caseinate combined coating. then, sodium nitrite in the sausage formulation was replaced by the carrier nanocapsules with different proportions and oxidative and microbial spoilage tests, color and sensory evaluations were performed for different treatments. materials and methodsat first, astaxanthin pigment was extracted from haematococcus pluvialis using the acid-acetone technique. then, the extracted pigment was nanoencapsulated using maltodextrin-sodium caseinate combined coating and the resulting (carrier) nanocapsules in the form of treatments a (120 mg/kg sodium nitrite), b (120 mg/kg nanocapsules carrying astaxanthin), c (90 mg/kg sodium nitrite+30 mg/kg nanocapsules carrying astaxanthin), d (60 mg/kg sodium nitrite+60 mg/kg nanocapsules carrying astaxanthin) and e (30 mg/kg sodium nitrite+90 mg/kg nanocapsules carrying astaxanthin) were replaced sodium nitrite in the sausage formulation. these treatments were evaluated in terms of oxidative and microbial spoilage, color indices and sensory properties during 28 days of storage at refrigerator along with the control (without sodium nitrite and carrier nanocapsules). this research was conducted in a completely randomized design. data were analyzed by one-way analysis of variance and the difference between the means was evaluated by duncan’s test at 95% confidence level. results and discussionaccording to the results, the lowest levels of thiobarbituric acid and peroxide value during the storage period were related to treatments b, e and d (p>0.05). treatments a and c  had no significant difference in terms of thiobarbituric acid and peroxide value until day 14 (p>0.05), but with increasing storage time, this difference became significant and treatment a showed higher values (p<0.05). the results of this section showed that the power of astaxanthin in controlling oxidative spoilage is significantly greater than sodium nitrite, and if the purpose is only to control this type of spoilage, there is no need to replace or use sodium nitrite. the results also showed that in terms of controlling microbial spoilage, sodium nitrite has more power than nanocapsules carrying astaxanthin. so that, the lowest amount of total volatile basic nitrogen (tvb-n) and the most standardized ph were related to treatments a, c and d (p>0.05) during the storage period (p<0.05). treatments b and e (p>0.05) were ranked next (p<0.05) in terms of the two mentioned indicators. the results of this section showed that if sodium nitrite reduced from 120 mg/kg to 60 mg/kg  and replaced by nanocapsules carrying astaxanthin in the sausage formulation, the resulting product has the same antimicrobial power as the product containing 120 mg/kg sodium nitrite. evaluation of the color and sensory properties of treatments showed that a, c and d treatments are at a higher level than b, e (treatments) and control in terms of color indices and general acceptance (p<0.05). the comparison of the color indices and sensory properties of the treatments on days 0 and 28 of storage at refrigerator showed that the color and sensory indices remained constant in the formulated treatments, unlike the control. conclusion nanocapsules carrying astaxanthin with maltodextrin-sodium caseinate combined coating as a natural product with many properties in health, control and prevention of various diseases, have a high efficiency to replace the sodium nitrite in sausage formulation. so that, if 30 to 60 mg/kg of the permissible limit of 120 mg/kg of sodium nitrite in the sausage formulation is replaced by nanocapsules carrying astaxanthin, the resulting product will be similar to the product containing 120 mg/kg of sodium nitrite in terms of shelf life, resistance to oxidative and microbial spoilage, color indices and sensory properties.