Fish Processing By-products Research Articles

IMPACT OF FISH PROCESSING BY-PRODUCT AMENDMENT ON SOIL PROPERTIES

A pot experiment was carried out at the Vytautas Magnus University Agriculture Academy in Lithuania to examine the possibilities of fish processing wastes to improve soil properties. The fish bones powder (FBP) was mixed with the soil, it was placed into the special vegetative pots of 5 l in volume up to the thickness of 25 cm. The soil type was Endocalcaric Endogleyic Luvisol (WRB 2014, update 2015) and according to granulometric composition was medium heavy loam. The experiment has designed in 4 variants and 6 replications. Soil samples were collected from the substrates in the vegetative pots 360 days (twelve months) after the application of fish processing by-products. The results obtained show that FBP application has significantly influenced the increase of organic carbon, available phosphorus, potassium and calcium contents in tested soil. The amount of FBP application didn’t show any noticeable impact on soil pH value, magnesium and sulphur content in medium heavy loam soil. Although the total nitrogen and mineral nitrogen contents have increased in soil a significant changes were found only after use of 6.5 t ha-1 FBP rate. The FBP application has significantly influenced the increase of microbiota abundance, microbial biomass C and microbial biomass N in tested soil. The microbial biomass C and N directly depended on the (FBP) rate.

Fish Gelatin Hydrolysates as Antioxidant, Antihypertensive, and Antidiabetic: The Plausible Mechanisms

Gelatin produced from fish processing by-product is the most potential alternative source of gelatin. They have biological activities, particularly antioxidant, antihypertensive, and reduce type 2 diabetic risk. This paper reviews the mechanisms of fish gelatin hydrolysates for those human diseases being discussed in recent studies. Based on the review, mostly, skin and bone are used as sources of fish-based gelatin in which about thirty percent comes from the weight of total fish. Some species have been analysed based on their bioactivities, including Tuna, Nile tilapia, Amur sturgeon, Pangasius catfish, Cod, Blacktip shark, Salmon, Halibut, and Tilapia fish. In short, the antioxidant mechanism of this fish-based gelatin is by scavenging and neutralizing the radicals. The antihypertensive mechanism is by inhibition of Angiotensin-Converting Enzyme (ACE) activity. Whilst the mechanism to reduce type 2 diabetes is by inhibiting dipeptidyl peptidase IV (DPP-IV) action.

Collagen-Based Bioactive Bromelain Hydrolysate from Salt-Cured Cod Skin

Considerable amounts of fish processing by-products are discarded each year. About 30% of this material may be skin and bone. Fish skin has more than 80% of its total protein content as collagen. Furthermore, in recent years, there has been a growing demand for collagen-based peptides due to their beneficial health effects. So, the objective of the present study was to optimise the obtaining bioactive hydrolysates from salt-cured cod skin using the protease Bromelain at 0.5% (w/w) concentration. This study developed a sustainable process that consumes less time and energy and uses an alternative source as raw material. In addition, bromelain allows hydrolysates with important antioxidant (ORAC, 514 μmol Trolox Equivalent/g protein) and antihypertensive activities (inhibition of ACE, IC50 of 166 μg protein/mL) as well as excellent biocompatibility with dermal and subcutaneous cells.

Obtaining Antioxidants and Natural Preservatives from Food By-Products through Fermentation: A Review

Industrial food waste has potential for generating income from high-added-value compounds through fermentation. Solid-state fermentation is promising to obtain a high yield of bioactive compounds while requiring less water for the microorganism’s growth. A number of scientific studies evinced an increase in flavonoids or phenolics from fruit or vegetable waste and bioactive peptides from cereal processing residues and whey, a major waste of the dairy industry. Livestock, fish, or shellfish processing by-products (skin, viscera, fish scales, seabass colon, shrimp waste) also has the possibility of generating antioxidant peptides, hydrolysates, or compounds through fermentation. These bioactive compounds (phenolics, flavonoids, or antioxidant peptides) resulting from bacterial or fungal fermentation are also capable of inhibiting the growth of commonly occurring food spoilage fungi and can be used as natural preservatives. Despite the significant release or enhancement of antioxidant compounds through by-products fermentation, the surface areas of large-scale bioreactors and flow patterns act as constraints in designing a scale-up process for improved efficiency. An in-process purification method can also be the most significant contributing factor for raising the overall cost. Therefore, future research in modelling scale-up design can contribute towards mitigating the discard of high-added-value generating residues. Therefore, in this review, the current knowledge on the use of fermentation to obtain bioactive compounds from food by-products, emphasizing their use as natural preservatives, was evaluated.

Evaluation of the Level of Toxic Contaminants and Essential Molecules in the Context of the Re-Use of Tuna Fishery Industry by-Products

The tuna fish processing industry produces more than 50% of waste and by-products (scales, head, viscera, etc.) that are usually discarded or used to produce low added value products such as fish meals. However, these waste materials still contain molecules essential for the human diet, such as essential metals, vitamins, omega-3 fatty acids, amino acids, and proteins of high nutritional value. The re-use of such wastes for the production of dietary supplements for human consumption would perfectly fit with the concept of Blue Economy, defined as the sustainable use of ocean resources for economic growth, improved livelihoods, and jobs while preserving the health of the ocean ecosystem. Moreover, waste product revenue will be a key factor in maintaining long-term profitability of industrial food processing. In this work, the yellowfin tuna (Thunnus albacares) was used as a model for fish processing by-products, as it is a large epipelagic species widely distributed in the tropical and subtropical waters of the major oceans. The determination of heavy metals and histamine is an essential control point for the re-utilization of the wastes. Then, they must be monitored in all the processes leading to the formulation of new high-quality products. Inductively coupled plasma–mass spectrometry and a fast gas chromatographic–mass spectrometry methods were validated and applied for the determination of metals and histamine and amino acids, respectively. In particular, both essential and heavy metals and histamine and amino acids were quantified in tuna fish by-products. The presence of essential metals and essential amino acids in the analyzed samples represents the strength point of the proposed model, which aims to valorize by-products and reduce the disposal of wastes.

Contribution of Quasifibrillar Properties of Collagen Hydrolysates Towards Lowering of Interface Tension in Emulsion-Based Food Leading to Shelf-Life Enhancement

This study was conducted to decipher the mechanism of emulsion-based food stabilization by fish-derived collagen hydrolysate. Collagen type I was isolated from seven fish processing by-products with yields ranging from 9.15 to 92.38%. The isolated samples had a mass of 110–120kDa and eluted at 30.44% NaCl in ion-exchange chromatography. The collagen samples were enzymatically digested to obtain collagen hydrolysate (CH) with mass <6kDa. The seven CH samples were subsequently screened for surface activity. CH obtained from Pacu skin and Tilapia bones exhibited more than 80% solubility over a wide pH range, zeta potential greater than +50mV, moisture retention up to 92–96%, emulsification activity of 53–70 m2g−1, and emulsion stability of 62–85min, and successfully increased the emulsion stability of a drug by 14 times. Both CH samples were able to retain the emulsion properties of butter and chocolate sauce for 25 weeks and did not show any cytotoxic effect on leukocytes and Vero cells. Structural studies revealed that the CH peptides existed in polyproline-II conformation that assembled to form a vast quasifibrillar network. Sequence analysis through tandem mass spectroscopy revealed that the peptides could be classified into multiple groups depending on the distribution of hydrophilic/lipophilic residues (H/L). The surface activity of the CH was found to be dependent on (1) small size and a wide array of H/L ratio, (2) abundance of hydroxyproline, and (3) assembly of the peptides in the emulsion interface to form a mimic-helix–based quasifibrillar network which ensured optimal orientation and subsequent interaction with multiple phases.

Gelatin from Milkfish Scales for Food Application

The amount of gelatin used worldwide in the food industry is increasing annually. Recovery of valuable components from fish processing-by products could help solve problems on tons of wastes produced each year and address religious beliefs like Islam and Judaism as well as the fear of mad cow disease. In this study, gelatin was extracted from milkfish scales for food application. The physical properties (yield, strength, color, clarity and pH) of extracted gelatin were studied and compared with commercially-available bovine gelatin. Marshmallows were developed from these gelatin sources. Sensory evaluation was done to determine the appropriateness of the level of a specific attribute and the consumer’s preference using the nine-point hedonic and just about right (JAR) scales. The extracted fish gelatin was comparable to bovine gelatin in terms of strength but they differ in terms of color, clarity and pH. The fish gelatin had a yield of 8.7%, high bloom value of 505g, white appearance and an acidic pH (5.25). The marshmallow developed from fish gelatin is comparable to bovine gelatin in all attributes (color, aroma, texture, taste, sweetness and aftertaste) except for sweetness. Overall, the gelatin extracted from milkfish scales can be used as an alternative to bovine gelatin for food application such as in marshmallow production.

Sustainable Management of Secondary Raw Materials from the Marine Food-Chain: A Case-Study Perspective

The feasibility of exploiting secondary raw materials from marine food-chains as a source of molecules of nutritional interest, to create high-value food products and to meet nutritional challenges, is described in this report. A reduction in food waste is urgent as many sectors of the food industry damage the environment by depleting resources and by generating waste that must be treated. The project herein described, deals with the recovery of natural molecules, omega-3 fatty acids (EPA, DHA) and of α-tocopherol, from fish processing by-products. This would promote the sustainable development of new food products for human nutrition, as well as nutraceuticals. The growing awareness of increasing omega-3 fatty acids intake, has focused attention on the importance of fish as a natural source of these molecules in the diet. Therefore, a study on the concentration of these bioactive compounds in such matrices, as well as new green methodologies for their recovery, are necessary. This would represent an example of a circular economy process applied to the seafood value chain. Fish processing by-products, so far considered as waste, can hopefully be reutilized as active ingredients into food products of high added-value, thus maximizing the sustainability of fish production.

A Narrative Review of the Anti-Hyperglycemic and Satiating Effects of Fish Protein Hydrolysates and Their Bioactive Peptides.

Prevalence of type 2 diabetes and overweight/obesity are increasing globally. Food supplementation as a preventative option has become an attractive option in comparison to increased pharmacotherapy dependency. Hydrolysates of fish processing waste and by-products have become particularly interesting in a climate of increased food wastage awareness and are rapidly gaining traction in food research. This review summarizes the available research so far on the potential effect of these hydrolysates on diabetes and appetite suppression. Scopus and Web of Science are searched using eight keywords (fish, hydrolysate, peptides, satiating, insulinotropic, incretin, anti-obesity, DPP-4 [dipeptidylpeptidase-4/IV]) returning a total of 2549 results. Following exclusion criteria (repeated appearances, non-fish marine sources [e.g., macroalgae], and irrelevant bioactivities [e.g., immunomodulatory, anti-thrombotic]), 44 relevant publications are included in this review. Stimulation of hormone secretion, regulation of glucose uptake, anorexigenic potential, identified mechanisms of action, and research conducted on the most potent bioactive peptides identified within these hydrolysates are all specifically addressed. Results of this review conclude that despite wide methodological variation between studies, there is significant potential for the application of fish protein hydrolysates in the management of bodyweight and hyperglycemia.

Characteristic of yellow tuna skin (Thunnus albacares) gelatin enriched with cinnamon (Cinnamomum zeylanicum) and roselle (Hibiscus sabdariffa) powder

The current practice condition of fish processing will generate some amounts of byproducts such as skin waste. These fish processing by-products can be considered as an alternative raw material for the preparation of high protein ingredients such as gelatin. Gelatin extraction from the skin of yellowfin tuna (Thunnus albacares) was conducted by the acid process. Afterwards, the fish gelatin was mixed with cinnamon (GECP) and roselle powder (GERP) to enhance the physicochemical and functional properties of gelatin. The effects of the addition of cinnamon (GECP) and roselle powder (GERP) on the physicochemical and the functional properties such as tensile strength, hardness, viscosity, water holding capacity, oil holding capacity, total flavonoid, total phenolic, total antioxidant and flavor compounds of enriched gelatin (GECP and GERP) from tuna skin were evaluated and compared with control (without the addition of cinnamon and roselle powder). The gelatin exhibited excellent tensile strength, WHC, OHC, total flavonoid, total phenolic, and antioxidant in the presence of cinnamon and roselle powder rather than control (without addition) (p&lt;0.05). The flavor analysis by using GC-MS showed more cinnamaldehyde as one important flavor compounds in GECP and where cyclohexanones can be identified as one important flavor compound in GERP. Thus, this study confirmed the improvement of physicochemical properties of gelatin enriched with cinnamon and roselle powder.

High Yields of Shrimp Oil Rich in Omega-3 and Natural Astaxanthin from Shrimp Waste.

A valued marine oil rich in omega-3 lipids and natural astaxanthin is obtained with remarkably high yield (up to 5 wt %) extending to pink shrimp waste (head and carapace) using the approach to extract fish oil from fish processing byproducts using d-limonene. Biobased limonene is an excellent solvent for both unsaturated lipids and astaxanthin-based carotenoids preventing oxidative degradation during the extraction cycle including solvent separation at 85 °C. Explaining the deep red color of the shrimp oil obtained, computational simulation suggests that d-limonene is also a good solvent for natural astaxanthin abundant in shrimp.

A novel cold biorefinery approach for isolation of high quality fish oil in parallel with gel-forming proteins.

The pH-shift process for isolation of gel-forming proteins from fish processing by-products was extended to allow parallel isolation of fish oil. Subjecting the floating emulsion layer formed during pH-shift processing of salmon by-products to pH-adjustment or freeze/thawing efficiently released the emulsified oil at 4°C. However, for herring by-products higher temperature (10°C) and a combination of the emulsion-breaking techniques was required for efficient oil release. Oil recovery yield using the adjusted pH-shift process was lower than with classic heat-induced oil isolation (90°C/20min), but pH-shift-produced oils had higher amounts of n-3 polyunsaturated fatty acids (n-3 PUFA). Also, alkaline pH-shift processing produced oils with remarkably less oxidation products and free fatty acids compared with acid pH-shift process or heat-induced isolation. Extending the pH-shift process with emulsion breaking techniques can thus be a promising biorefinery approach for parallel cold production of high-quality fish oil and gel-forming proteins from fish by-products.

Optimising enzymatic conditions of monkfish (Lophius vomerinus) heads hydrolysis towards potential waste biomass valorisation

Enzymatic protein hydrolysis of fish processing by-products offers an alternative option to valorise this raw material. Monkfish heads originating from fish processors presents such an opportunity, as the heads constitute a significant portion of the total fish (approximately 30%) and are currently processed into relatively low-value fish meal or even discarded. In this study, the reaction conditions for enzymatic protein hydrolysis of monkfish heads were optimised by varying the reaction pH and temperature using the Alcalase proteolytic enzyme. A mixed 2-factor, 3-level factorial design was employed to determine significant factors and interactions and was followed by response surface optimisation to determine optimal enzymatic hydrolysis conditions, which were shown to occur at 62 °C and a pH of 8.2. In addition, proximate analysis of the raw material and functional property characterisation of both the aqueous fish protein hydrolysate (FPH) phase and the insoluble sediments were performed to maximise the possibility of total raw material utilisation. Both the FPH and sediment displayed functional and bioactive properties, including emulsion stabilisation, fat absorption and antioxidant activity; only the FPH displayed foaming capacity, while the sediment displayed a reasonable emulsion activity index. In addition, high levels of essential amino acids (EAA) were found in the sediment (49.5% of the total amino acids), and all EAA were present (except tryptophan, which was not analysed for), which confirmed the high quality of the protein contained in the sediment. Overall, this work successfully optimised hydrolysis conditions for the Alcalase/monkfish system and confirmed the potential of enzymatic protein hydrolysis as an upgrading strategy to better utilise monkfish processing by-products.

The Role of Selected Lactic Acid Bacteria on Organic Acid Accumulation during Wet and Spray-Dried Fish-based Silages. Contributions to the Winning Combination of Microbial Food Safety and Environmental Sustainability.

Organic acid contents of acidified and fermented fish silages made from gibel carp (Caracius gibelio) and klunzinger’s ponyfish (Equulites klunzingeri) fishes, and from fish processing residues or by-products, were determined and studied. The silages were undertaken in wet and spray-dried fish-based raw-materials for 3 weeks at room temperature (ca. 25 °C). Selected lactic acid bacteria (LAB) of Enterococcus gallinarum, Lactobacillus brevis, Lactobacillus plantarum, Pediococcus acidilactici, and Streptococcus spp. were employed to produce fermented fish-based silages, while acidified silage was prepared resorting to the addition of formic acid (3%, v/v). Lactic and propionic acids were the dominant produced organic acids, while succinic acid was formed at the smallest amounts in fermented silages. In the acidified silage, lactic and formic acids were produced in amounts higher than 800 and 1000 mg organic acid/100 g sample, respectively. Among the fermented fish-based silages, LAB strains unfolded considerable ability to presumptively produce propionic acid in gibel carp silage (>2370 mg organic acid/100 g sample). Spray-dried fermented silages displayed significantly higher organic acid content than wet silages. Propionic acid accumulation was found at the highest levels in gibel carp silage fermented with L. plantarum (6335.40 mg propionic acid/100 g sample). This research effort pointed out the good capability of various selected lactic acid bacteria strains to produce significant amounts of organic acids—especially lactic, acetic, and propionic acids—during the fermentation of fish-based silages. In terms of food safety and quality, such a production of relatively high amounts of organic acids in wet and spray-dried fish-based silages clearly indicated their suitableness to be used for animal feed.

The use of fermentation for rational processing of fish: a review

Fermentation is widely used for conservation of food products. In many regions of the world fermentation is used for production of large amount of fish processing by-products that are currently being disposed or used for production of low-value products. There is a large potential for reducing the amount of by-products and utilizing a larger amount of fish processing by-products for high value products. With the use of fermentation, it can be possible to produce a broad spectrum of food products as well as food ingredients for wide range of applications. Therefore, the main aim of the study is to perform the analysis of literature sources on the use of fermentation for rational fish processing.

Physicochemical properties and sensory attributes of local snacks fortified with powdered fish processing by-products and an underutilised fish species

Fish processing by-products and small pelagic fish could provide minerals and protein in diets of vulnerable populations as these could be more affordable than seafood. The study objectives were to determine the proximate nutrient content of tuna processing by-products and burrito fish and also assess the acceptability of fish powder-fortified local carbohydrate snacks. Tuna trimmings, gills, frames and burrito were dried at 55oC for eight hours to moisture levels of 4.8% (trimmings), 8.9% (frames), 6.8% (gills) and 6.9% (burrito). The products were milled and incorporated at varying levels into four local snacks namely: mpotompoto, yakayake, abolo and yam balls. Proximate nutrient levels of both fortified and non-fortified snacks were determined by Official Methods of Analysis (AOAC). Protein contents of mpotompoto-fortified fish products ranged from 3.75% to 8.5%. Ash also ranged from 1.12% to 5.54%. The control contained 1.17%. Acceptability tests were conducted on the fortified snacks using a 5-point hedonic scale. On the whole, fortified products showed significantly higher levels of protein and ash over the non-fortified snacks. Acceptance of the snacks by pupils (11-12) years was high enough to warrant incorporation of the fish powders into a school lunch menu.

Fish Scale Valorization by Hydrothermal Pretreatment Followed by Enzymatic Hydrolysis for Gelatin Hydrolysate Production

Protein hydrolysates from fish by-products have good process suitability and bioavailability in the food industry. The objective of this work was to develop a method for protein recovery from fish scales and evaluate the hydrolysis of the scale protein. The effect of the hydrothermal process on protein recovery, degree of hydrolysis (DH) and structural properties of the hydrolysates was investigated. Results showed that hydrothermal treatment could enhance protein recovery of tilapia scales without demineralization and dramatically improve the DH of the hydrolysates. The hydrothermal treated scales showed a better protein recovery (84.81%) and DH (12.88%) and released peptides more efficiently than that of the conventional treated samples. The obtained gelatin hydrolysates mainly distributed in the range of 200–2000 Da with an angiotensin I-converting enzyme (ACE) IC50 value of 0.73 mg/mL. The ACE inhibitory activity of gelatin hydrolysates was stable under high temperature, pH and gastrointestinal proteases. Hydrothermal treatment followed by enzymatic hydrolysis offers a potential solution for preparation of gelatin hydrolysates for food ingredients from fish processing by-products.

Linking Production and Consumption: The Role for Fish and Seafood in a Healthy and Sustainable Australian Diet.

Fish and seafood consumption in Australia has been growing, yet the implications of this trend across the food system, from both a health and sustainability perspective have not been fully explored. This paper aims to map out the fish and seafood food system in Australia, linking production and consumption, to articulate challenges and opportunities for enhancing the sector’s contribution to future healthy and sustainable diets. We conducted a secondary analysis of publicly available datasets on fish and seafood production and consumption, triangulated and supplemented with peer-reviewed and grey literature on environmental, economic and social sustainability issues throughout the food system. A key challenge for health is the high proportion of fish and seafood consumed as discretionary food, particularly among children. Key challenges for sustainability include the narrow focus on environmental sustainability (with little consideration of the other domains), and the focus on production with little consideration for sustainability throughout post-harvest handling, processing, retail, distribution and consumption. Key opportunities for health and sustainability include the innovative use of processing and packaging technology to maximise nutritional quality; creation of markets and supply chains for a greater diversity of underutilised fish and seafood species and processing by-products; and reductions in waste and loss throughout the entire supply chain.

Bitterness of fish protein hydrolysate and its debittering prospects.

Fish processing by-products often generated as discard can enzymatically be processed into a product known as fish protein hydrolysates (FPH). FPH is a good source of amino acid and peptides with bioactivities. FPH can be added to foods to improve nutritive values and bioactivities. However, bitterness in FPH, associated with hydrophobicity, degree of hydrolysis, molecular weight, proline residues, type of enzymes, and amino acid sequences has limited its uses in foods. Thus, FPH is used in foods at low levels. Numerous procedures such as extraction with alcohol, activated carbon treatment, Maillard reaction, cyclodextrin, chromatographic separation, and enzymatic hydrolysis with exopeptidase and plastein reaction have been explored to remove the bitterness of FPH. These methods can lower bitterness and improve its taste. However, changes in structure and loss of some peptides may occur. FPH with less or no bitterness can thereforebe used at higher levels to alleviate nutrition deficiencies in foods. PRACTICAL APPLICATIONS: Fish protein hydrolysate (FPH) is a nutritive ingredient, which can be produced from fish processing by-products. However, bitterness in FPH has limited its potential use as a nutritive ingredient. As a result, it is incorporated into foods at low levels. Nevertheless, application of several reported debittering processes could assist to solve the problem of bitterness in FPH. The debittering can improve sensory property of FPH, thus widening its utilization.

Use of Protease from Seabass Pyloric Caeca in Combination with Repeated Freeze–Thawing Cycles Increases the Production Efficiency of Virgin Coconut Oil

Virgin coconut oil (VCO) is separated from coconut milk using partially purified protease from seabass pyloric caeca (PPSP) in combination with different treatments including micro‐fluidization, chill–thawing, and freeze–thawing. The lowest VCO yield is obtained for coconut milk homogenized at 4000 psi, followed by hydrolysis using PPSP at the level of 5 units g−1 proteins. Conversely, the higher VCO yield is obtained from non‐homogenized and unhydrolyzed coconut milk (p &lt; 0.05). Coconut milk hydrolyzed by PPSP at 10 units g−1 protein, followed by freeze–thawing shows the highest yield among all the samples (p &lt; 0.05). VCO yield increases as chill–thawing cycles of hydrolyzed coconut milk increases up to 5 cycles (p &lt; 0.05). A similar trend is found in sample subjected to hydrolysis, followed by freeze–thawing. Hydrolysis by PPSP, followed by freeze–thawing of 5 cycles, yields the highest yield of VCO (98.6%). No marked difference is observed in fatty acid profile, moisture content, free fatty acid content, and oxidative stability of all VCO obtained, regardless of subsequent chill–thawing and freeze–thawing applied. All VCO samples are in the range of APCC standards. Thus, combined treatment including hydrolysis using PPSP followed by freeze–thawing (5 cycles) is a powerful method for extraction of VCO, in which high yield and prime quality could be gained.Practical Applications: In VCO production, the cost of commercial enzyme and yield of VCO are of major concern. Therefore, a cheap source of proteases, particularly fish processing byproducts, can be a promising alternative for VCO production. Additionally, a combined method, especially enzymatic hydrolysis of coconut milk followed by freeze–thawing, can be a practical process to obtain VCO with increased yield. The information on combined methods can be of benefit in manufacturing VCO with reduced cost and high yield.The use of protease from seabass pyloric caeca in combination with repeated freeze‐thawing cycles increases the production efficiency of virgin coconut oil.