Effect of antioxidants on the sensory quality and physicochemical stability of Atlantic mackerel (Scomber scombrus) fillets during frozen storage

Oxidative Stability of Side-Streams from Cod Filleting-Effect of Antioxidant Dipping and Low-Temperature Storage

Currently, side-streams (e.g., head, backbone, tail, and intestines) generated in the fish processing industry often end up as low-value products for feed applications or even as waste. In order to upcycle such side-streams, they need to be preserved to avoid oxidative degradation of the lipids between the generation point and the valorization plant. In the cod filleting industry, three main solid side-streams: viscera, heads, and backbones, are obtained. Hence, this study aimed to identify the most efficient antioxidant for preserving the cod side-streams using a dipping-based strategy prior to pre-valorization storage at low temperatures (ice and frozen storage). The dipping solutions evaluated contained: (i) a lipophilic rosemary extract (0.05% and 0.2% in 0.9% NaCl), (ii) Duralox MANC (a mixture of rosemary extract, ascorbic acid, tocopherols, and citric acid; 2% in 0.9% NaCl), and (iii) NaCl (0.9%) w/w solution. One group was not dipped. No dipping and dipping in NaCl were included as controls. The results showed a positive effect of dipping with solutions containing antioxidants as measured by peroxide value (PV), TBA-reactive substances (TBARS), and sensory profiling, e.g., rancid odor. Moreover, the oxidative stability increased with decreased storage temperature. The cod side-streams were in general most efficiently preserved by Duralox MANC, followed by the lipophilic rosemary extract (0.2%), compared to no dipping and dipping in NaCl solution and the lower concentration of the lipophilic rosemary extract (0.05%). The efficiency of the antioxidant treatments was independent of the side-stream fraction and storage temperature. Thus, using antioxidant dipping combined with low temperature storage is an efficient preservation method for maintaining the quality of the lipids in cod solid side-streams during their pre-valorization storage.

Effects of Ultrasound-Assisted Immersion Freezing on the Protein Structure, Physicochemical Properties and Muscle Quality of the Bay Scallop (Argopecten irradians) during Frozen Storage

In this study, the comparison effects of ultrasound-assisted immersion freezing (UIF) at different ultrasonic power, immersion freezing (IF), and air freezing (AF) on the protein thermal stability, protein structure, and physicochemical properties of adductor muscle of scallop (Argopecten irradians) (AMS) during frozen storage were investigated. Principal component analysis and the Taylor diagram were used to comprehensively analyze all the indicators tested. The results showed that the UIF at 150 W (UIF-150) treatment was the most effective way to delay the quality deterioration of AMS during 90-day frozen storage. This was mainly because, compared to AF and IF treatments, UIF-150 treatment more effectively minimized the changes in the primary, secondary and tertiary structures of myofibrillar proteins, and it preserved the protein thermal stability of AMS by producing small and regular ice crystals in the AMS tissue during the freezing process. Moreover, the results of physicochemical properties indicated that UIF-150 treatment significantly inhibited the fat oxidation and microbiological activities of frozen AMS, and it finally maintained the microstructure and texture of AMS during frozen storage. Overall, UIF-150 has potential industrial application prospects in the rapid freezing and quality preservation of scallops.

Prevention of quality characteristic decline in freeze-thawed cultured large yellow croaker (Larimichthys crocea) using flammulina velutipes polysaccharide

To investigate the cryoprotective effect of flammulina velutipes polysaccharide (FVP) on the quality characteristics in freeze-thawed cultured large yellow croaker, 0.050%, 0.075%, and 0.100% FVP was used before freezing and the quality after thawing was compared with water soaking (WS) and commercial cryoprotectant (CC) treatment. Quality attributes were comprehensively determined instrumentally and organoleptically after thawing at 4°C. Results showed that FVP effectively reduces the quality deterioration of body color and water-holding capacity, while no obvious effects were observed in texture and flavor. As for body color, both FVP and CC treatment could maintain the b* value to a large extent. Among them, 0.075% FVP shows the highest value in two sample points, with 55.2% and 21.0% increases seen in the values in WS. FVP-dose-dependent trends were found in water-holding capacity, where a reduction of 28.26% and 14.38% in thawing loss and cooking loss was observed in the 0.100% FVP group. Low-field nuclear magnetic resonance (LF-NMR) also revealed that immobilized water and free water were more tightly retained in the muscle tissue with FVP addition. The results of the sensory evaluation are essentially in line with the above observations. These findings indicate that FVP has the potential to partially replace commercial cryoprotectants in aquatic products during frozen storage.

Cutting Techniques in the Fish Industry: A Critical Review

Fish and fishery products are among the most important sources of nutritional components for human health, including high-quality proteins, essential vitamins, minerals, and healthy polyunsaturated fatty acids. Fish farming and processing technologies are continuously evolving to improve and enhance the appearance, yield, and quality of fish and fish products from farm to fork throughout the fish supply chain, including growth, postharvest, treatment, storage, transportation, and distribution. Processing of fish involves a period of food withdrawal, collection and transportation, the process of stunning, bleeding, chilling, cutting, packaging, and byproduct recycling. Cutting is a set of crucial operations in fish processing to divide the whole fish into smaller pieces for producing fish products (e.g., fish fillets, steaks, etc.). Various techniques and machinery have been introduced in the field to advance and automate cutting operations. This review aims to provide a comprehensive review of fish cutting techniques, machine vision and artificial intelligence applications, and future directions in fish industries. This paper is expected to stimulate research on enhancing fish cutting yield, product diversity, safety and quality, as well as providing advanced solutions for engineering problems encountered in the fish industry.

Effects of Chitosan-Grafted-Phenolic Acid Coating on Quality and Microbiota Composition of Vacuum-Packaged Sea Bass (Lateolabrax japonicus) Fillets during Chilled Storage

ABSTRACT

The aim of this research was to experimentally assess the effect of chitosan (CS)-grafted phenolic acid (CS-g-PA) derivatives on the quality and microbiota composition of vacuum-packaged sea bass (Lateolabrax japonicus). Samples were treated by deionized water (CK), 1% CS, 1% CS-g-PA copolymer, and 1% CS-grafted gallic acid (CS-g-GA) copolymer for 10 min and combined with vacuum packaging stored at 4°C to analyze the microbiological and physicochemical indicators; they were also combined with 16s RNA high-throughput sequencing to explore the effects of CS derivatives on quality and microbial composition. The results showed that the treatment of CS-g-GA and CS-g-PA could retard the increase of pH, total volatile basic nitrogen, and the K value. The degradation of ATP-related compounds, production of biogenic amines, and growth of spoilage bacteria were inhibited by CS-g-GA and CS-g-PA. Moreover, CS-g-GA and CS-g-PA performed better in the inhibition of lipid oxidation by the analysis of thiobarbituric acid reactive substances and relative fluorescence intensity. According to the results of high-throughput sequencing, the diversity of microbial composition in all groups was decreased significantly during chilled storage, especially in the CK group. The predominant microorganism was Acinetobacter in the middle period of storage, while Pseudomonas and Shewanella became predominant at the end of storage. The treatment of CS-g-GA and CS-g-PA had significant effects inhibiting the growth of Shewanella during storage. On the basis of the analysis of the microorganism and physicochemical quality, compared with the CK group, CS-g-GA and CS-g-PA can maintain the good quality of sea bass fillets and prolong the shelf life for another 12 days.

HIGHLIGHTS

Changes in Protein and Non-Protein Nitrogen Compounds during Fishmeal Processing—Identification of Unoptimized Processing Steps

Quality changes of protein and non-protein nitrogen compounds during industrial fishmeal processing of fatty pelagic species (mackerel/herring rest material blend, MHB) and lean fish (whole blue whiting, BW) were studied to identify processing steps that require optimization to allow production of products for human consumption. Samples from protein-rich processing streams throughout the fishmeal production were analyzed for proximate composition, salt soluble protein content (SSP), biogenic amines (BA), total volatile basic nitrogen (TVB-N), trimethylamine (TMA), and dimethylamine (DMA). Mass flows throughout processing were balanced based on the total mass and proximate composition data. The quality of the final fishmeal products was highly dependent on the fish species being processed, indicating that the processes require optimization towards each raw material. The chemical composition changed in each processing step, resulting in different properties in each stream. Most of the non-protein nitrogen compounds (including BA, TVB-N, TMA, and DMA) followed the liquid streams. However, the concentrate contributed less than 20% to the produced fishmeal quantity. Mixing of this stream into the fishmeal processing again, as currently carried out, should thus be avoided. Furthermore, the cooking, separating, and drying steps should be optimized to improve the water and lipid separation and avoid the formation of undesired nitrogen compounds to produce higher-value products intended for human consumption.

Effect of antioxidants on lipid oxidation in herring (Clupea harengus) co-product silage during its production, heat-treatment and storage

Provided high product quality, ensilaging can be used to valorize fish filleting co-products into a silage suitable for food applications. However, a documented challenge for products from hemoglobin-rich fish raw materials is the high susceptibility to lipid oxidation, calling for stabilization by antioxidants. In a comparison among different rosemary-containing antioxidants and isoascorbic acid, we here found that the commercial mixture Duralox MANC-213 (MANC) provided the best protection against peroxide value and 2-thiobarbituric acid reactive substances (TBARS) development during ensilaging of herring filleting co-products (0–7 days, 22 °C), and also during subsequent heat-treatment (30 min, 85 °C). Increasing MANC concentration from 0.25 and 0.75 to 1.25% lowered TBARS values from 43.53 and 25.12 to 18.04 µmole TBARS/Kg silage, respectively, after 7 days of ensilaging. During storage at 4 °C/22 °C in presence of MANC, 1.25% provided the highest protection with 87–90% and 66–73% lower TBARS, at 4 °C and 22 °C, respectively, at 6 months compared to the controls. At this time point, heat-treated silages had lower protein degree of hydrolysis and free amino acids values than the non-heat-treated one. Regardless of antioxidant addition, total volatile basic nitrogen (TVB-N) formation still increased during the storage, but, overall, TVB-N values in silages were below the acceptable limit of 30 mg TVB-N/100 g fish for human consumption. Together with lipid oxidation data, this suggest that herring silage produced in presence of antioxidants can be used both for high quality feed and food applications.

Lipid oxidation and antioxidant delivery systems in muscle food

Lipid oxidation accelerates quality deterioration in muscle-based foods (fish, red meat, and poultry), resulting in off-odors/flavors, color problems, texture defects, and safety concerns. Adding antioxidants is one approach to control lipid oxidation, and several delivery strategies have been applied, such as supplementing antioxidants to the feed, direct mixing into minces, or, for whole muscle pieces; spraying, glazing, and injection. However, some issues linked to these technologies hinder their wide utilization, such as low effectiveness, noncompatibility with clean label, and off-flavor. These shortcomings have promoted the development of new antioxidant delivery technologies. In this review, the main focus is on the principles, characteristics, and implementation of five novel antioxidant delivery methods in different types of muscle food products. Their advantages and drawbacks are also summarized, plus comments about future trends in this area. Among novel routes to deliver antioxidants to muscle foods are, for whole tissues, recyclable dipping solutions; for minces, encapsulation; and, for both minces and whole tissues, cross-processing with nonmuscle antioxidant-containing raw materials as well as applications of edible films/coatings and active packaging. Advantages of these technologies comprise, for example, low price, the possibility to control the antioxidant release rate, overcoming strong aromas from natural antioxidants, and allowing antioxidant-containing raw materials from the food industry to be valorized, providing an opportunity for more circular food production.

Effects of Ultrasound-Assisted Vacuum Impregnation Antifreeze Protein on the Water-Holding Capacity and Texture Properties of the Yesso Scallop Adductor Muscle during Freeze-Thaw Cycles

The effect of antifreeze protein (AFP) on the water-holding capacity (WHC) and texture properties of the Patinopecten yessoensis adductor muscles during freeze–thaw cycles (FTCs) were evaluated based on three impregnation methods: general impregnation (GI), vacuum impregnation (VI), and ultrasound-assisted VI (US-VI). The WHC, texture properties, and tissue microstructure were all evaluated. Results showed that the WHC and texture properties of adductor muscle were significantly improved in the VI and US-VI groups during FTCs (p < 0.05). The WHC of the adductor muscle in the US-VI group was maximally enhanced in terms of yield (6.63%), centrifugal loss, cooking loss, and T₂₂. The US-VI group of the adductor muscle had the optimal chewiness and springiness compared to others, and the shear force and hardness were most effectively enhanced by VI. The growth and recrystallization of ice crystals in the frozen adductor muscle were significantly inhibited by VI and US-VI. The average cross-sectional area and roundness of ice crystals in the US-VI group were decreased by 61.89% and increased by 22.22% compared with those of the control, respectively. The partial least squares regression (PLSR) model further confirmed that the WHC and texture properties of the adductor muscle were correlated appreciably with the degree of modification of ice crystal morphology through the AFP.

Effect of short-term frozen storage on taste of gonads of female Eriocheir sinensis and the classification of taste quality combined with sensory evaluation and fuzzy logic model

To investigate the taste quality of gonads of Eriocheir sinensis during frozen storage, the difference in overall taste profile was determined by electronic tongue, and the contents of free amino acids and 5'-Nucleotides were measure. The results showed that the overall taste profile of samples during frozen storage could be effectively distinguished. The contents of free amino acids and 5'-Nucleotides increased with the extension of frozen storage time. The content of water-soluble substances stored at -20 ℃ was higher than those of stored at -40 and -80 ℃. In addition, taste was evaluated by equivalent umami concentrention (EUC) and taste active value (TAV). The sensory evaluation results indicated that with the extension of frozen storage time, umami, sweetness and saltiness decreased, while bitterness increased, which was inconsistent with the previous experimental results. Sensory verification experiments were carried out to prove that bitterness could inhibit umami, sweetness and saltiness. Fuzzy logic model was used to classify the taste of gonads during frozen storage, with Hypoxanthine (Hx), Lysine (Lys) and Histidine (His) as input variables and twelve flavor grades as output variables. Finally, taste was evaluated using the designed model. When the gonads were stored at -20, -40 and -80 °C, the Pearson correlation coefficients between storage time and the taste grade of gonads were 0.98, 0.99 and 0.99, respectively.

Bacterial Diversity of Sun-Dried Spanish Mackerel in Dalian and Application of Lactobacillus plantarum X23 as a Biopreservative

ABSTRACT

Sun-dried Spanish mackerel is a common food in Dalian and made by adding salt and sun drying, which has special physical, chemical, and microbiological properties. In this study, the physicochemical properties and microbial composition of commercially available sun-dried Spanish mackerel in Dalian were assessed, and some Lactobacillus strains were screened as a biopreservative for sun-dried Spanish mackerel preparation. The results showed that the total volatile base nitrogen content in the traditional sun-dried Spanish mackerel samples from Dalian was within 30 mg/100 g, the histamine content was 7 to 17 mg/kg, and the dominant bacteria at the genus level were Lactobacillus, Psychrobacter, and Ralstonia. A strain with biopreservative potential was isolated from a sun-dried Spanish mackerel sample, identified as L. plantarum species by 16S rDNA sequencing, and assigned as L. plantarum X23. Fresh Spanish mackerel flesh was treated with 16% brine and L. plantarum X23 at a dose of 107 CFU/mL and then dried in the sun. The sun-dried Spanish mackerel flesh treated with 16% brine and L. plantarum X23 showed a decreased histamine and acid value, increased free amino acid content, and a higher sensory score compared with the sun-dried Spanish mackerel without L. plantarum X23 treatment (P < 0.05). In conclusion, the sun-dried Spanish mackerel purchased from the supermarkets in Dalian were safely edible, and L. plantarum X23 can significantly reduce the content of histamine and putrescine in self-made, low-salt, sun-dried Spanish mackerel and has potential as a biopreservative for sun-dried Spanish mackerel preparation.

HIGHLIGHTS

Recent developments of natural antimicrobials and antioxidants on fish and fishery food products

Fish and fishery products (FFP) are highly perishable due to their high nutritional value and moisture content. The spoilage is mainly caused by microorganisms and chemical reactions, especially lipid oxidation, leading to losses in quality and market value. Microbiological and lipid deteriorations of fishery-derived products directly lower their nutritive value and pose the risk of toxicity for human health. Increasing demand for safe FFP brings about the preservation using additives from natural origins without chemical additives due to their safety and strict regulation. Antimicrobials and antioxidants from natural sources have exhibited an excellent control over the growth of microorganisms causing fish spoilage via different mechanisms. They also play a major role in retarding lipid oxidation by acting at various stages of oxidation. Antimicrobials and antioxidants from natural sources are usually regarded as safe with no detrimental effects on the quality attributes of FFP. This review provides recent literature on the different antioxidant and antimicrobial agents from natural sources, focusing on microbial and oxidative spoilage mechanisms, their inhibition system, and their applications to retard spoilage, maintain safety, and extend the shelf life of FFP. Their applications and benefits have been revisited.

Quality and Shelf-Life Modeling of Frozen Fish at Constant and Variable Temperature Conditions

The objective of this study was the investigation of the effect of variable conditions on quality parameters and the shelf life of fish during frozen storage. Three different fish products were tested, i.e., gilthead sea bream (Sparus aurata) fillets, sea bass (Dicentrarchus labrax) fillets, and yellowfin tuna (Thunnus albacares) slices stored in the range of −5 to −15 °C. The kinetic modeling of different shelf-life indices was conducted. Sensory scoring of frozen fish showed high correlation with color (L-value) and total volatile basic nitrogen (TVBN). The temperature dependence of the rates of quality degradation was expressed via the activation energy values, calculated via the Arrhenius equation, and ranged, for the tested quality indices, between 49 and 84 kJ/mol. The estimated kinetic parameters were validated at dynamic conditions and their applicability in real conditions was established, allowing for their practical application as tools for cold chain management.