Impact of traditional and mild oven cooking treatments on antioxidant compounds levels and oxidative status of Atlantic salmon (Salmo salar) fillets

Impact of Modern Oven Treatments on Lipid Oxidation and Vitamin E Content of Fillets from Sardine (Sardina pilchardus) at Different Reproductive Cycle Phases

The beneficial effects of sardine consumption can be related to the presence of bioactive compounds, such as vitamin E and ω3 polyunsaturated fatty acids. In any case, the levels of these compounds in sardine fillet depend on different factors mainly related to the diet and reproductive cycle phase of the fish as well as the technological treatments carried out to cook the fillets. The aim of the present study is two-fold: first, to evaluate changes in the total fatty acid profile, lipid oxidation, and vitamin E content of raw fillets from sardine (Sardina pilchardus) at different reproductive cycle phases (pre-spawning, spawning, and post-spawning); and second, to highlight how these nutritional profiles are affected by three oven treatments (conventional, steam, and sous-vide). For this purpose, raw fish was grouped into pre-spawning, spawning, and post-spawning phases according to the mesenteric fat frequency and the gonadosomatic index evaluation, and submitted to conventional (CO), steam (SO), and sous-vide (SV) baking. The ratio of EPA/DHA and vitamin E increased from post-spawning to pre-spawning, to spawning. Considering the reproductive phases, baking affected the oxidative degree differently: a CO > SO ≥ SV impact was found in the worst scenario (post-spawning), mitigated by vitamin E, to CO ≥ SO > SV in the best scenario (spawning). SV was the best treatment with high values of vitamin E in pre-spawning individuals (110.1 mg/kg). This study shows how vitamin E is correlated to the combined effect of endogenous and exogenous factors.

Growth and Welfare Status of Giant Freshwater Prawn (Macrobrachium rosenbergii) Post-Larvae Reared in Aquaponic Systems and Fed Diets including Enriched Black Soldier Fly (Hermetia illucens) Prepupae Meal

Due to the limited application of insect meal in giant freshwater prawn (Macrobrachium rosenbergii) culture, the present study aimed to (i) produce spirulina-enriched full-fat black soldier fly (Hermetia illucens) prepupae meal (HM) and (ii) test, for the first time, two experimental diets characterized by 3% or 20% of fish meal and fish oil replacement with full-fat HM (HM3 and HM20, respectively) on M. rosenbergii post-larvae during a 60-day feeding trial conducted in aquaponic systems. The experimental diets did not negatively affect survival rates or growth. The use of spirulina-enriched HM resulted in a progressive increase in α-tocopherol and carotenoids in HM3 and HM20 diets that possibly played a crucial role in preserving prawn muscle-quality traits. The massive presence of lipid droplets in R cells in all the experimental groups reflected a proper nutrient provision and evidenced the necessity to store energy for molting. The increased number of B cells in the HM3 and HM20 groups could be related to the different compositions of the lipid fraction among the experimental diets instead of a nutrient absorption impairment caused by chitin. Finally, the expression of the immune response and stress markers confirmed that the experimental diets did not affect the welfare status of M. rosenbergii post-larvae.

Spirulina-enriched Substrate to Rear Black Soldier Fly (Hermetia illucens) Prepupae as Alternative Aquafeed Ingredient for Rainbow Trout (Oncorhynchus mykiss) Diets: Possible Effects on Zootechnical Performances, Gut and Liver Health Status, and Fillet Quality

In the present study, an organic substrate (coffee silverskin) enriched with spirulina (Arthrospira platensis; 15% w/w), as a source of lipids and bioactive molecules, was used to rear the black soldier fly (Hermetia illucens) prepupae. Three grossly isonitrogenous, isoproteic, isolipidic and isoenergetic experimental diets for rainbow trout (Oncorhynchus mykiss) juveniles were then produced: a control diet (HM0) mostly including fish meal and fish oil, and two other test diets named HM3 and HM20, in which 3 or 20% of the marine ingredients were substituted with full fat black soldier fly prepupae meal (HM), respectively. Experimental diets were provided for 6 weeks, and at the end of the trial the physiological responses and marketable traits of the fish were investigated using a multidisciplinary approach. Generally, all test diets were well accepted, and fish growth, gut and liver health status, and marketable characteristics were not impaired by the experimental diets. However, an increased immuno-related gene expression along with a slight reduction of fillet redness and yellowness was evident in fish from the HM20 group.

Effects of immersing treatment of curcumin and piperine combined with vacuum packaging on the quality of salmon (Salmo salar) during cold chain logistics

In order to study the effects of the compound preservatives (curcumin and piperine (CP)) and vacuum packaging (VP) on the quality of salmon during cold chain logistics suffered from temperature abuse, the physiochemical indexes (texture, water holding capacity (WHC), total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), free amino acids (FAA) contents), microbial indicators (total mesophilic bacteria count (MBC), total psychrotrophic bacteria count (PBC), H2S-producing bacteria count (HSBC)) were determined, and the moisture changes were explored by near-infrared (NIR) spectroscopy and low-field nuclear magnetic resonance (LF-NMR). The results showed that the treatment of curcumin and piperine in combination with vacuum packaging could maintain the quality of salmon suffered from temperature abuse most effectively. At the end of storage, the MBC of VP+CP was only 4.95 log CFU/g, which was about 1 log CFU/g lower than the control sample stored at the same condition. The combined treatment also retarded the increase of TVB-N, TBARS, and the decrease of hardness, springiness, and a* value, as well as water migration in salmon, contributing to higher water holding capacity and better appearance. Besides, VP+CP retarded the decrease of free glutamate, which contributed to umami taste. Due to the biological activity and safety of the preserves, the combined treatment could be a promising method for preservation of seafood.

Fatty Acid Profile, Physicochemical Composition, and Sensory Properties of Atlantic Salmon Fish (Salmo salar) during Different Culinary Treatments

This study was conducted to assess the effects of boiling, steaming, and oven-cooking on the fatty acid profile, physicochemical composition, and sensory properties of Atlantic salmon fish. The protein content of steamed (18.90%) and oven-cooked (20.59%) salmon was significantly higher than that of boiled (16.69%) and raw fish (14.73%). Analysis of the fatty acids profile revealed that steaming significantly ( $p<0.05$ ) influenced the fatty acid contents of Atlantic salmon by recording the lowest SFA and the highest omega-3, omega-6, and PUFA contents. Textural properties such as hardness, gumminess, and chewiness were significantly higher ( $p<0.05$ ) in oven-cooked salmon, with steamed salmon having significantly lower and higher values of hardness (75.32 ± 4.73) and springiness (90.56 ± 3.94), respectively. Also, volatile organic compounds, including aldehydes, ketones, and alcohol, were significantly higher ( $p<0.05$ ) in oven-cooked and steamed salmon. Additionally, the E-nose sensors analysis showed that S2 and S7 were significantly correlated during oven-cooking and steaming. Furthermore, low-field NMR analysis showed that the values of T21 and T22 relaxation characteristics of raw and cooked samples fluctuated, with steamed salmon having the highest peak values indicating reduced proton mobility and increased freedom of the protons compared to other treatments. Therefore, steaming resulted in the best quality salmon when considering the fatty acid profile, physicochemical composition, and sensory properties of Atlantic salmon fish, suggesting further studies to ascertain its effectiveness compared to modern treatments.

The Influence of Sous Vide Parameters on Nutritional Characteristics and Safety of Pikeperch Fillets

The aim of the study was to investigate the influence of temperature and time combination on the quality of pikeperch fillets and to propose settings which allow high nutritional quality fish fillets to be obtained. The material for the study consisted of 24 farmed pikeperch (Sander lucioperca) fillets, which were evaluated raw and after sous vide (SV) cooking proceeded at 65 °C for 45 min (SV65), 75 °C for 20 min (SV75), and 90 °C for 10 min (SV90). The chemical composition was affected by SV procedure; SV90 was similar to raw samples in terms of moisture, protein, and fat content, whereas SV65 differed the most. Carnosine contents decreased in all SV samples compared with raw ones, and anserine only decreased in SV90. There were no differences in terms of fatty acid composition (% of total) between SV and raw samples. In SV75 and SV90 total viable counts, Enterobacteriaceae, Enterococcus sp., and Staphylococcus sp. were reduced below a detection level but not in SV65. These samples also showed a better sensory quality than SV65. Therefore, SV75 and SV90 might be recommended for pikeperch fillets preparation, taking into account safety and nutritional aspects.

Bioavailability Study of Isothiocyanates and Other Bioactive Compounds of Brassica oleracea L. var. Italica Boiled or Steamed: Functional Food or Dietary Supplement?

The levels of bioactive compounds in broccoli and their bioavailability following broccoli intake can be affected by the cooking procedures used for vegetable preparation. In the present pilot study, we compared the human plasma bioavailability of antioxidant compounds (β-carotene, lutein and isothiocyanate) and of phylloquinone (vitamin K) on seven volunteers before and after the administration of boiled and steamed broccoli. Moreover, plasma isothiocyanate (ITCs) levels were also evaluated after the administration of a single dose of BroccoMax^®, a dietary supplement containing GLSs with active myrosinase. Steam-cooking has been demonstrated to promote higher plasma bioavailability in ITCs than boiling (AUC_STEAMED = 417.4; AUC_BOILED = 175.3) and is comparable to that reached following the intake of BroccoMax^®, a supplement containing glucoraphanin and active myrosinase (AUC = 450.1). However, the impact of boiling and steaming treatment on plasma bioavailability of lipophilic antioxidants (lutein and β-carotene) and of phylloquinone was comparable. The lutein and β-carotene plasma levels did not change after administration of steamed or boiled broccoli. Conversely, both treatments led to a similar increase of phylloquinone plasma levels. Considering the antioxidant action and the potential chemopreventive activity of ITCs, steaming treatments can be considered the most suitable cooking method to promote the health benefits of broccoli in the diet.

Impact of Mild Oven Cooking Treatments on Carotenoids and Tocopherols of Cheddar and Depurple Cauliflower (Brassica oleracea L. var. botrytis)

The effect of steam and sous-vide oven procedures on liposoluble antioxidants of colored cauliflower (orange and purple) was assessed for the first time and compared with domestic practice (boiling). In raw samples, the total carotenoid content was 10-fold higher in Cheddar than in Depurple (20.9 ± 2.1 vs. 2.3 ± 0.5 mg/kg dry weight), whereas the level of tocopherols was similar (28.5 ± 4.4 vs. 33 ± 5.2 mg/kg dry weight). The Cheddar liposoluble antioxidant matter contained violaxanthin, neoxanthin, α-carotene and δ-tocopherol, not detected in Depurple. All tests increased the bioactive compounds extractability with steam oven and sous-vide displaying similar effects, lower than boiling. In boiled Cheddar cauliflower, the total carotenoids and tocopherols contents increased with cooking time until they were 13-fold and 6-fold more than in raw cauliflower, respectively. Conversely, in the Depurple variety, contents increased by half with respect to the orange variety. However, from a nutritional point of view, no differences were revealed among the three different cooking treatments in terms of vitamin A and E levels expressed in μg/100 g of fresh vegetable because of the higher water content of boiled samples that must be considered when evaluating the effect of thermal treatment on cauliflower nutritional traits.

Salmon (Salmo salar) Cooking: Achieving Optimal Quality on Select Nutritional and Microbiological Safety Characteristics for Ready-to-Eat and Stored Products

This study was performed in order to assess technological characteristics, proximate composition, fatty acids profile, and microbiological safety of sous-vide processed salmon in comparison with steaming and roasting. The cooking loss was lower in the sous-vide method (6.3-9.1%) than in conventional methods (11.6-16.2%). The preparation of salmon using sous-vide was more time- and energy-consuming than steaming. The dry matter content of the salmon fillets was higher in conventionally processed samples than sous-vide due to the evaporation of water, and it was connected with total protein (r = 0.85) and lipid content (r = 0.73). Analysis of the fatty acids profile only revealed significant differences in six fatty acids. All of the heat treatment methods ensured microbiological safety with regard to coagulase-positive Staphylococcus, E. coli, Listeria monocytogenes, and Salmonella spp. However, in sous-vide (57 °C, 20 min) and steamed samples after storage Enterobacteriaceae bacteria (<104) was detected. Summing up, high parameters of sous-vide salmon cooking, when considering both technological parameters, nutritional value, and microbiological status should be recommended.