تاثیر کنستانتره آب نارنج و پوشش خوراکی کیتوزان غنی شده با اسانس فلفل سیاه بر بهبود خواص آنتی‌اکسیدانی و حسی فیله ماهی قزل‌آلای رنگین کمان

تمایل به استفاده از نگهدارنده های طبیعی و جایگزین کردن آنها به‌جای نگهدارنده های شیمیایی سبب گردیده است مطالعات مختلفی در مورد ترکیبات طبیعی دارای خواص آنتی‌اکسیدانی و میکروبی مانند اسانس‌ها صورت پذیرد. در پژوهش حاضر اثرات کنسانتره آب نارنج و پوشش کیتوزان حاوی اسانس فلفل سیاه بر فساد شیمیایی فیله ماهی قزل آلای رنگین کمان نگهداری شده در یخچال مورد سنجش قرار گرفت. نمونه‌ها به 8 گروه تقسیم شدند و در دوره زمانی 12 روزه شاخص‌های ph، بازهای نیتروژنی فرار، تیوباربیتوریک اسید، میزان پراکسید، اسیدهای چرب آزاد و ارزیابی حسی مورد بررسی قرار گرفتند. همچنین نمونه‌ها از نظر فعالیت آنتی‌اکسیدانی به روش dpph (دی فنیل پیکریل هیدرازیل) و rp (قدرت احیاکنندگی) ارزیابی گردیدند. با بررسی نتایج مشخص گردید که نمونه شاهد نسبت به سایر تیمارها به‌صورت معناداری افزایش روند شاخص‌های اکسایشی و حسی را نشان داد و در نمونه‌های پوشش داده شده نیز نمونه ماهی دارای کیتوزان، کنسانتره آب نارنج و اسانس فلفل سیاه کمترین میزان شاخص ها را نسبت به بقیه به‌خود اختصاص داد. از نظر مهار رادیکال dpph، کنسانتره آب نارنج با بریکس1.39 و درصد مهار 66.9% و اسانس فلفل2% با درصد مهار 64.1% توانایی بیشتری داشته اند. در بررسی فساد اکسایشی و ارزیابی حسی در تمامی آزمون ها نمونه کیتوزان به همراه اسانس فلفل و کنسانتره آب نارنج با کسب امتیاز 7.2 از پانل ارزیابی حسی بهتر از سایر تیمارها ارزیابی شد. نتایج حاصله نشان‌دهنده تاثیر مثبت کنسانتره آب نارنج و پوشش کیتوزان دارای اسانس فلفل سیاه در مدت زمان نگهداری بر کیفیت فیله ماهی قزل آلای رنگین کمان می‌باشد.

Effect of orange juice concentrate and chitosan coating enriched with black pepper (Piper nigrum) essential oil on improvement of antioxidant and sensory properties of rainbow trout (Oncorhynchus mykiss) fillet

Introduction: Nowadays, consumers are applicant to usage of natural replacements causing to side effects of synthetic preservatives such as carcinogenicity and teratogenicity. The tendency to use natural preservatives and replacing them with chemical preservatives has led to various studies of natural compounds with antioxidant properties such as essential oils. Considering the environmental problems raised from current plastic packaging, edible and biodegradable coating could be developed and also be effective in controlling the chemical and microbial properties of food; especially if their effect be strengthened by adding natural antioxidant and antimicrobial agents like herbal essential oils. Various herbal compounds such as black pepper essential oils with antioxidant properties can be effective in combining with natural biodegradable coatings such as chitosan in oxidation control and enhance the effects or prevent or delay the chemical spoil. Safety and shelflife of foods can be improved by using this technologies such as using natural preservatives. Adding essential oil, as a suitable source of antioxidant, for improvement the quality of the fish is the main purpose. Many fruits, especially orange, are rich in polyphenols. These materials are the most commonly existing phytochemicals in most fruits. Orange juice concentrate can be a good source of antioxidant and can be employed as a preservative in food products. Omega3 fatty acid is used in daily healthy diet and plays an important role in prevention of disease. Being a considerably main source of Omega3 fatty acid groups, fish preservation against oil oxidation and any other similar causatives seems quite necessary. In the present study, the effects of orange juice concentrate and chitosan coating enriched with black pepper essential oil on the chemical degradation of rainbow trout fillet stored in a refrigerator investigated.; Materials and methods: The chemical composition of black pepper essential oils were determined using a gas chromatography equipped with mass spectroscopy (GC/MS). GCMS analysis of the essential oil was performed using AgilentTechnologies 6890N Network gas chromatographic (GC) system, equipped with Agilent Technologies 5975 inert XL Mass selective detector and AgilentTechnologies 7683 B series auto injector (AgilentTechnologies, Little Falls, CA, USA). Samples were stored at 4 ± 1 C° up to 12 days and evaluated periodically ( on days 0, 4, 8 and 12) for chemical and sensory characteristics. The samples were divided into 8 groups and assessed for PHvalues, total volatile nitrogen (TVN), thiobarbituric acid (TBA), peroxide value (PV), free fatty acids (FFA) and sensory evaluation .The samples were also evaluated for antioxidant activity by measuring their scavenging abilities to DPPH radical (2,2 diphenyl1picril hydrazyl) and RP (Reducing power). Statistical analysis was performed using SPSS 20 software.; Results & Discussion: Results showed that More than 21 compounds were identified in oil, representing 97.75% of the total oil. The major constituents of essential oils obtained from the black pepper were βcaryophyllene (25.56%), Limonene (15.19%), Sabinene(12.2) , αcopaene(8.5) and beta –bisabolene (7.81) respectively. Results revealed that in comparison to the other treatments the control showed a significant increase in the trend of oxidative and sensory indexes and In the coated samples, the sample of fish coated with orange juice concentrate ,chitosan, and black pepper essential oil was the least amount of indexes than the rest (p <0/05) and showed lower indexes during the storage time .The radical scavenging DPPH, orange juice concentrate with a Brix 1/39 (66/9 %)and pepper essential oil 2% (64/1%) have more ability and had a greater antioxidant activity. In investigating corruption oxidation and sensory evaluation in all samples,chitosan coating with pepper essential oil and orange juice concentrate was higher(score:7/2) than other treatments and there were significant differences between treatment and control (p <0/05). Final peroxide value (meq O2/Kg oil) and tiobarbituric acid (m gr/kg oil MD) number using chitosan coating with pepper essential oil and orange juice concentrate in sample was 0.14 and 0.015, respectively. This significant deference was also observed when comparing to control sample (p <0.05)Minimum oxidative changes were observed in samples treated with orange juice concentrate,chitosan, and black pepper essential oil and had the best conditions in reduction of oxidative rancidity. The results obtained in this study showed that the chitosan coating enriched with black pepper essential oil with orange juice concentrate has a good potential to being employed as an active packaging to preserve food products. Overall, this study demonstrated that using concentrated juice incorporated with chitosan coating with pepper essential oil has a good effect on the quality of rainbow trout fillets and can keep on the sensorial attributes acceptably during 12 days storage time and present a good potential for their application in the food industry.;