تاثیر انواع روش‌های پخت در میزان چربی و اسیدهای چرب چندغیراشباع ضروری (امگا-3) فیله ماهی کپور سرگنده (hypophthalmichthys nobilis)

ماهی بیگ هد پرورشی (hypophthalmichthys nobilis) با وزن متوسط 100±700 گرم از یک مزرعه پرورش ماهی تهیه و به آزمایشگاه فرآوری پژوهشکده اکولوژی دریای خزر انتقال داده شد. نمونه‌ها پس از فیله شدن، با روش‌، سرخ کردن (با روغن آفتابگردان) و کبابی کردن در آون پخته شدند. سپس از لحاظ شاخص‌‌های شیمیایی (پروتئین خام، چربی خام، رطوبت و خاکستر) و پروفایل اسیدهای چرب با استفاده از کروماتوگرافی گازی و شاخص‌‌های اکسیداسیون (عدد پراکسید، تیوباربیوتیک اسید و بازهای نیتروژنی فرار)، فیله ماهی خام و پخته شده اندازه‌گیری گردید. نتایج نشان داد که مقدار رطوبت، چربی خام، پروتئین خام و خاکستر در نمونه شاهد ماهی بیگ هد به‌ترتیب، 76.86، 1.49، 19.06 و 1.91 درصد بود. اعمال روش‌های متفاوت پخت سبب کاهش رطوبت حدود 10-6 درصد، افزایش پروتئین حدود 7-5 درصد شد و مقادیر چربی در ماهی سرخ شده به میزان 2 درصد افزایش یافت. تمامی روش‌های پخت موجب افزایش شاخص‌های اکسایشی چربی شدند (0.05>p). سرخ کردن موجب افزایش مقادیر پراکسید (3.86 میلی اکی والان/ کیلوگرم چربی)، تیوباربیتوریک اسید (2.04میلی گرم آلدهید اسید) و بازهای نیتروژنی فرار (19.20 میلی گرم/ صد گرم) گردید. مقادیر اسید چرب در روش کبابی در اکثر موارد اختلاف معنی‌داری با فیله خام نداشت. کبابی کردن نیز تاثیری بر نسبت امگا 3 به امگا 6 نداشت (0.05p). بنابراین، پخت به روش کباب کردن روش مناسب‏تری جهت حفظ ارزش تغذیه‌ای فیله ماهی کپور سرگنده ماهی نسبت به سایر روش‌های پخت است.

influence of different cooking methods on the lipid and essential polyunsaturated fatty acids (omega-3) contents of bighead carp (hypophthalmichthys nobilis) fillet

introductionseafood is an excellent source of high-quality protein, essential fatty acids, vitamins, and minerals. in terms of fish quality, the most basic element is to measure the approximate composition of the flesh along with its fatty acid composition (hedayati fard and miri, 2017). the bighead carp (hypophthalmichthys nobilis) is one of the most important warm-water fish species in the world, which has a special place in multi-species culture systems worldwide due to its high adaptability (dadras et al., 2011). fish oil contains high amounts of essential unsaturated fatty acids such as eicosapentaenoic acid (epa), docosahexaenoic acid (dha) and 5 to 6 double bonds, essential minerals and vitamins (el-lahamy et al., 2019). humans obtain most of their essential fatty acids, especially epa and dha, from the consumption of fish, aquatic invertebrates and macroalgae (hedayati fard and miri, 2017). in modern societies, meat is almost always cooked before consumption. heating is a common method for food processing. heat (boiling, steaming, frying, microwave, etc.) in foods inactivates pathogenic microorganisms and lipolytic enzymes, improves sensory quality (smell and taste), increases digestibility, and increases shelf life. most changes in quality issues in cooked fish products are directly related to the quality of the initial raw material. heating is one of the common methods in food processing. in research conducted on different cooking methods, the fatty acid composition of biyah fish oil treated with fennel alcoholic extract was studied. the results showed that the oven-baked sample had the lowest moisture (51.97%) and the highest protein (39.69%) during cooking (ramzani et al., 2016). different cooking methods affect the quality characteristics of fish, including texture, taste, smell, color, and overall acceptance (momenzadeh et al., 2017). the purpose of the research is to measure different cooking methods (grilling and frying) that cause significant changes in the quality indicators and fatty acid compositions of bighead carp fillets. considering the above, the nutritional value of bighead carp was determined by applying different cooking methods and the effect of these cooking methods on the fatty acid analysis of the fillets, in order to introduce the best cooking method.methodology frying method: fish fillets were fried in oil at 180°c for 8 minutes (zakipur rahimabadi and bakr, 2011). oven roasting method: oven roasting (un55, memmert, gr) was performed at 180°c for 30 minutes (hedayatifard and miri, 2017). approximate compounds measurement: moisture weighing was performed by oven drying at 105°c (avak and glaser, 2005). the protein samples were analyzed using the kjeldahl method (avak and glaser, 2005). fat weighing was performed using the soxhlet method (bilgin et al., 2010). ash measurement was determined by the 190°c oven method (avak and glaser, 2005). the measurement of (pv) peroxide values was performed by iodine titration method (ronald and ronald, 1991). thiobarbituric acid (tba) was measured colorimetrically (hedayatifard and miri, 2017). total volatile bases-nitrogen (tvb-n) was measured by the kjeldahl method (hedayatifard and miri, 2017). identification of fatty acid profiles and composition was performed using a gas chromatography (agilent technol 7890-gc) equipped with a flame ionization detector (fid) with a capillary tube and a column of 50 m × 0.25 mm and 0.2 μm (hedayatifard and miri, 2017). study the ratios of pufa/sfa and mufa/sfa fatty acids were investigated (brimani et al.,2021). the nutritional quality index of epa+dha and the n-3/n-6 ratio were examined as an important index for comparing the nutritional value of fish oil in the present study (bayir et al.,2006). index (pi), index (hh), atherogenic index (ai) and thrombogenic index (ti) were investigated in raw, fried and oven-baked fillets. (brimani et al.,2021). the data analysis and variance homogeneity were performed by the (on-way anova) method.results the results of the moisture content study showed that it was significantly higher in raw fish than in other cooking methods (76.86%), and the lowest moisture content was observed in fried fish (66.62%) (p<0.05). the results showed that the percentage of protein in fried fish was significantly higher than other cooking methods (26.26%), and the lowest protein levels were observed in the raw fish treatment (19.60%) (p<0.05). the results showed that the percentage of fat in fried fish was significantly higher than other cooking methods (70.3%). the lowest fat levels were observed in the oven-baked fish treatment (17.1%) (p<0.05). the results showed that the ash content in oven-cooked fish (kebab) was significantly higher than other cooking methods (2.77%), and the lowest ash content was observed in raw fish treatment (1.90%) (p<0.05). the results of the peroxide value pv study showed that it was significantly higher in fried fish than in other cooking methods (386.3 milliequivalents per kilogram of fat) (p<0.05), and the lowest peroxide value was observed in the raw fish treatment (0.94 milliequivalents per kilogram of fat) (figure 5) (p<0.05). the results of the study showed that the levels of thiobarbituric acid in fried fish were significantly higher than those in other cooking methods (2.04 mg malondialdehyde/kg acid) (p<0.05), and the lowest levels of thiobarbituric acid were observed in the raw fish treatment (0.54) (figure 6) (p<0.05). the results of the study showed that the total volatile nitrogen bases tvb-n in fried fish were significantly higher than other cooking methods (17.10 mg/100 g) (p<0.05), and the lowest values ​​of volatile nitrogen bases were observed in the raw fish treatment (10.35 mg/100 g) (figure 7) (p<0.05). results related to the amounts of saturated fatty acids (sfa) in raw and cooked fish by different cooking methods identified five types of saturated fatty acids (c14:0, c16:0, c18:0, c20:0 and c22:0) (table 1). results of the study of polyunsaturated fatty acids (pufa) identified 6 types of acids (c18:2n-6, c18:3n-3, c20:3n-6, c20:3n-3, c20:5n-3 (epa), c22:6 n-3 (dha) (table 1). in the study of monounsaturated fatty acids (mufa), 3 types of monounsaturated fatty acids were identified (c16:1, c18:1, and c20:1) (table 1). the results of the composition of pufa/sfa fatty acids showed that the minimum recommended value, i.e. 0.4, was higher (brimani et al., 2021). the mufa/sfa ratio for all 3 treatments showed that the highest amount was related to fried fish and the lowest amount was related to grilled fish (table 2) (hosseini et al., 2014). the dha index was higher in raw fish than in cooked fish, and the lowest values ​​were observed in fried fish (table 2). the n-3/n-6 index was shown in 3 treatments. the lowest n-3/n-6 ratio was observed in fried samples and the highest n-3/n-6 ratio was observed in raw fillets (table 2) (bayir et al., 2006). the lowest values ​​of pi were observed in fried fish (table 2) (brimani et al., 2021). the hh index in all 3 treatments was within the appropriate range (table 2) (brimani et al., 2021). the atherogenic index (ai) and thrombogenic index (ti) were very low in 3 samples (table 2) (brimani et al., 2021). as a result of the present study, grilling is a more suitable method for cooking fish and the fish has an acceptable nutritional value.discussion and conclusion maintaining the nutritional value of fish can be achieved by using appropriate cooking methods (uran and gokoglu, 2014). the decrease in moisture is due to denaturation of the protein structure and evaporation of water (delfieh et al., 2013). the increase in protein in the fried treatment (kebab) is due to the decrease in moisture content of the samples compared to the relative increase in other components and the dissolution of some nitrogen (de castro et al., 2007). the increase in fat in the fried sample is due to the decrease in meat juice due to evaporation and penetration of oil into the tissue (qayumi et al., 2011). the increase in ash in the cooked sample is due to the decrease in moisture and increase in dry matter and the absence of minerals in the thermal process (abroomand and masoudi, 2012). the increase in peroxide in the fried sample is due to the increase in temperature. in fact, in the frying method, the production of free radicals is greater and they attack fatty acids more quickly and cause the production of hydroperoxides (ozogul et al., 2009). the high content of thiobarbituric acid in fried samples and the low content in raw samples is due to the high temperature, malonaldehyde level and fat oxidation increase (campo et al., 2006). an increase in (tvb-n) was observed in fried fish and its decrease in raw treatment. this is due to the thermal processing of the samples, which causes the decomposition of proteins, amino acids and other nitrogenous compounds (mohan et al., 2006). suggestions: 1- the effect of using natural preservatives on the fat content of fish cooked in different ways. 2- the effect of frying oils from different sources of oil plants on the quality of fish fillets.conflict of interestthe authors declare that they have no conflict of interestacknowledgmentthe authors wish to convey their heartfelt appreciation to all colleagues who supported and facilitatedthe experiment’s necessary infrastructure.