Evaluation of nitrogenous compounds, microbial changes and electrophoresis pattern during fermentation of Mahyaveh, the Iranian traditional fish sauce

Mahyaveh, the Iranian traditional fish sauce is a product with distinct flavor that is produced by fermentation of small and underutilized fish species in the presence of high salt concentration. Fish sauce is mainly used as food flavoring and seasoning in the southern provinces of Iran such as Hormozgan and Fars. In this research, the process of Mahyaveh preparation from the Persian Gulf anchovies was performed in the lab. Fish sauce was prepared by incubating mixtures of anchovies and saturate brine in the pottery containers at 37 C during 54 days of fermentation. The total changes in bacterial count and nitrogenous compounds were investigated in all of six stages of fermentation. The results showed that the total nitrogenous compounds including formaldehyde nitrogen, amino acid and volatile nitrogen increased sharply during the periods of fermentation but trimethylamine contents dramatically reduced in the final stage after increasing moderately in the early stages of fermentation. High Pearson correlation (r=0.8) between total bacterial count and trimethylamine confirmed the existence of relationship between these variables in the process of fish sauce fermentation. The results of SDS-PAGE pattern showed that the number and intensity of protein bands were reduced during fermentation time

Application of Essential Oils for Shelf-Life Extension of Seafood Products

This chapter will discuss the antimicrobial and antioxidant activities of various essential oils on possible shelf-life extension of different seafood products. Furthermore, the effect of antimicrobial coatings incorporated with various essential oils on the shelf-life of seafood products will be investigated. Microbiological and physico-chemical properties such as total count, psychrophilic and lactic acid bacterial count, peroxide test, thiobarbituric acid (TBA) test, total volatile basic nitrogen (TVB-N) test, and pH, also sensory evaluations of seafood products will be included. During this chapter the effect of chemical composition of some essential oils on the antimicrobial and antioxidant activities will be discussed briefly

Exploitation of Ultrasound Technique for Enhancement of Microbial Metabolites Production

Microbial metabolites have significant impacts on our lives from providing valuable compounds for nutrition to agriculture and healthcare. Ever-growing demand for these natural compounds has led to the need for smart and efficient production techniques. Ultrasound is a multi-applicable technology widely exploited in a range of industries such as chemical, medical, biotechnological, pharmaceutical, and food processes. Depending on the type of ultrasound employed, it can be used to either monitor or drive fermentation processes. Ultrasonication can improve bioproduct productivity via intensifying the performance of living organisms. Controlled ultrasonication can influence the metabolites' biosynthesis efficiency and growth rates by improvement of cell permeability as well as mass transfer and nutrient uptake rates through cell membranes. This review contains a summarized description about suitable microbial metabolites and the applications of ultrasound technique for enhancement of the production of these metabolites as well as the associated downstream processing

Physical, mechanical and antibacterial properties of the gelatin film obtained from the by-product of Talang queenfish, Scomberoides commersonnianus

In this study, gelatin was extracted from the by-product of Scomberoides commersonnianus, and after evaluating its characteristics, a biodegradable film was prepared from the gelatin. The results showed that the yield of extracting gelatin, pH and hardness were 12%, 5, and 100 grams, respectively. The gelation time and temperature were 18°C in 175 seconds. Evaluation of the mechanical properties of the edible film based on fish gelatin showed that the tensile strength and elongation at the break point were 3.6 MPa and 27.2%, respectively. The physical properties of thickness, humidity, solubility, and water vapor permeability were reported as 0.08 mm, 5.2%, 21.3%, and 5.8 g mm/h mm2kpa × 10-6, respectively. SEM images showed a smooth structure without pores. Moreover, gelatin film did not show antibacterial properties against E. coli, Staphylococcus aureus, Bacillus subtilis, and Bacillus cereus. However, based on the results of the fish gelatin film can be introduced as a suitable candidate for the preparation of composite films with other biopolymers, and the addition of antibacterial compounds can improve their antibacterial property

Innovation in the Seafood Sector through the Valorization of By-Products

Aquatic, marine and algae, is reservoir of bioactive compounds, which have considerable potential to supply novel ingredients toward the development of commercial functional food products. Meanwhile, several valuable by-products generate during the manufacturing process. Seafood is still an intact reservoir of valuable compounds with significant potential to provide unique compounds applicable in functional food development. Seafood, as an important part of the diet all around the world, can be used as a source of functional components that are positively affecting the human health. Annually, 50–80 percent of the seafood processing is discarded as waste every year. Algae are also the novel natural resources for their biological and pharmacological properties. This chapter will be discussing the innovations in seafood and algae sector through the valorization of their by-products. Firstly, protein production, its characterization and the protein hydrolysates derived from seafood will be reviewed. Subsequently, bioactivity of the peptides obtained from these protein hydrolysates and other bioactive compounds such as carotenoid compounds derived from seafood including fish, shrimp, alga, and so on will be included. Finally, the main components of algae including sulfated polysaccharides, pigments and proteins will be surveyed

The global burden of cancer attributable to risk factors, 2010-19 : a systematic analysis for the Global Burden of Disease Study 2019

Background Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. Methods The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk-outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. Findings Globally, in 2019, the risk factors included in this analysis accounted for 4.45 million (95% uncertainty interval 4.01-4.94) deaths and 105 million (95.0-116) DALYs for both sexes combined, representing 44.4% (41.3-48.4) of all cancer deaths and 42.0% (39.1-45.6) of all DALYs. There were 2.88 million (2.60-3.18) risk-attributable cancer deaths in males (50.6% [47.8-54.1] of all male cancer deaths) and 1.58 million (1.36-1.84) risk-attributable cancer deaths in females (36.3% [32.5-41.3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20.4% (12.6-28.4) and DALYs by 16.8% (8.8-25.0), with the greatest percentage increase in metabolic risks (34.7% [27.9-42.8] and 33.3% [25.8-42.0]). Interpretation The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.Peer reviewe

Identification of low molecular weight compounds produced or utilized by pychrotrophic meat spoilage organisms

Meat Juice Medium (MJM), an aqueous extract of meat, was inoculated with Pseudomonas aeruginosa and incubated for 7 d at 4$sp circ$C under shaking conditions (100 rev.min$sp{-1}$). Two predominant compounds produced during spoilage of MJM were detected using HPLC. These compounds with retention times (RT) of 21.48 and 32.04 min were tentatively identified as acetic and butyric acids, respectively. These compounds were also produced when MJM was replaced with Brain Heart Infusion Broth medium. In later experiments, the effect of glucose supplementation on the rate of MJM spoilage was examined. Glucose 0.5% (wt/vol) was added to the MJM, inoculated with P. aeruginosa and incubated at 30$sp circ$C under shaking conditions (100 rev.min$sp{-1}$). HPLC of samples after 1d of incubation indicated the presence of 8 predominant compounds including acetic and butyric acids. Their concentrations were, in general, higher in control samples of MJM without added glucose. Using HPLC, TLC, Pyrolysis/GC/MS, FTIR and GC-MS methodologies, the compounds with RT of 8.91, 9.67, 11.96, 13.33, 17.74, 21.48, 26.07 and 32.04 min were tentatively identified as cadaverine, 2-keto gluconic acid, fructose, lactic acid, acetic acid, methanol and butyric acid. In contrast to the results of previous researchers, cadaverine was produced in large amounts while no putrescine was produced by P. aeruginosa. During the spoilage period, the levels of glucose, fructose and total carbohydrate were monitored. Addition of glucose to MJM delayed slime production by 4 days and increase to maximum pH of 8.3 by 7 days. Results suggest that addition of glucose to MJM delays spoilage by P. aeruginosa

Protein structural changes during preparation and storage of surimi

Myofibrillar proteins, the main components that impart functional properties to muscle foods, can undergo denaturation and aggregation during frozen storage. The overall objective of this research was to study the changes in protein structure that are associated with the preparation and frozen storage of surimi. In addition, the relative cryoprotective effects of whey protein concentrate, whey protein isolate, soy protein isolate, flaxseed meal and flaxseed protein were assessed in surimi during storage.Raw surimi was prepared by repeatedly washing Alaska pollock flesh with chilled water. The product was either slowly frozen or underwent rapid freezing using liquid air; in either case it was then subjected to frozen storage at -20°C for 24 months. Protein structural changes were monitored using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), native-PAGE, Fourier transform infrared/attenuated total reflectance (FTIR/ATR) spectroscopy, and differential scanning calorimetry (DSC).FTIR/ATR spectroscopy showed that during preparation of surimi the alpha-helix content increased with increased number of washing cycles. DSC results revealed a shift in the thermal transition of actin to a higher temperature during surimi preparation. All electrophoresis, FTIR/ATR spectroscopy and DSC results revealed a loss of myofibrillar proteins from surimi after three washing cycles, suggesting that three washing cycles were adequate to prepare surimi.Native-PAGE showed no major changes in surimi after 24 months storage at -20°C. SDS-PAGE showed relatively minor changes in protein subunit structure with some loss of the myosin light chains (MLC); myosin heavy chain (MHC), actin and tropomyosin were found to be relatively stable. FTIR/ATR spectroscopy indicated a significant decrease in alpha-helix relative to beta-sheet structure in surimi after 2 years of storage at -20°C. The loss of alpha-helical content was more significant in slowly frozen surimi compared to rapid-frozen surimi samples. DSC results revealed a shift in the thermal transition of actin to lower temperatures during frozen storage of surimi.Changes in the ratio of alpha-helix to beta-sheet structures suggested that flaxseed protein was the most effective cryoprotectant, followed by whey protein isolate and soy protein isolate, for maintaining protein structure stability during frozen storage. Whey protein concentrate and flaxseed meal showed the least cryoprotective ability. After 15 days storage at 4°C, the SDS-PAGE results showed that flaxseed protein was the only cryoprotectant that prevented the degradation of myosin heavy chain, actin and myosin light chains

Comparison of various chemometric analysis for rapid prediction of thiobarbituric acid reactive substances in rainbow trout fillets by hyperspectral imaging technique

Abstract This study explores the potential application of hyperspectral imaging (HSI; 430–1,010 nm) coupled with different linear and nonlinear models for rapid nondestructive evaluation of thiobarbituric acid‐reactive substances (TBARS) value in rainbow trout (Oncorhynchus mykiss) fillets during 12 days of cold storage (4 ± 2°C). HSI data and TBARS value of fillets were obtained in the laboratory. The primary prediction models were established based on linear partial least squares regression (PLSR) and least squares support vector machine (LS‐SVM). In full spectral range, the prediction capability of LS‐SVM (RP2 = 0.829; RMSEP = 0.128 mg malondialdehyde [MDA]/kg) was better than PLSR (RP2 = 0.748; RMSEP = 0.155 mg MDA/kg) model and LS‐SVM model exhibited satisfactory prediction performance (RP2 > 0.82). To simplify the calibration models, a combination of uninformative variable elimination and backward regression (UB) was used as variable selection. Nine wavelengths were selected. Various chemometric analysis methods including linear PLSR and multiple linear regression and nonlinear LS‐SVM and back‐propagation artificial neural network (BP‐ANN) were compared. The simplified models showed better capability than those were built based on the whole dataset in prediction of TBARS values. Moreover, the nonlinear models were preferred over linear models. Among the four chemometric algorithms, the best and weakest models were LS‐SVM and PLSR model, respectively. UB‐LS‐SVM model was the optimal models for predicting TBARS value in rainbow trout fillets (RP2 = 0.831; RMSEP = 0.125 mg MDA/kg). The establishing of lipid‐oxidation prediction model in rainbow trout fish was complicated, due to the fluctuations of TBARS values during storage. Therefore, further researches are needed to improve the prediction results and applicability of HIS technique for prediction of TBARS value in rainbow trout fish

Shelf-life extension of whole shrimp using an active coating containing fish skin gelatin hydrolysates produced by a natural protease

This study was focused on shelf-life extension of whole shrimp (Penaeus merguiensis) using an active coating containing gelatin hydrolysates. Gelatin extracted from Scomberomorus commerson skin was hydrolyzed using actinidin extracted from kiwifruit. Some important physicochemical characteristics of fish skin gelatin including viscosity, gelling and melting points, and temperatures were examined. The whole shrimp was coated with four coating agents including fish skin gelatin (FG), commercial gelatin (CG), fish skin gelatin containing 1 mg/ml fish gelatin hydrolysates (FG + GH), and commercial bovine gelatin containing 1 mg/ml fish gelatin hydrolysates (CG + GH). Chemical, microbial, and sensorial properties of samples were monitored for 12 days at 4°C with 3-day intervals (0–12 days). The pH value of samples coated with FG + GH and CG + GH showed the lowest changes during 12 days of storage (1.68 ± 0.00 and 1.70 ± 0.09, respectively). The free fatty acid content (FFA), total volatile base nitrogen (TVB-N), lipid oxidation, and carbonyl content of samples coated with FG + GH and CG + GH were significantly lower than that of control, CG, and FG samples. The results of this study showed that the gelatin hydrolysates could be used as a preservative costing agent for whole shrimp