Texture is one of the food quality attributes affecting the consumer's acceptability and the market value. Fish and shellfish undergo weakening or softening of muscle, particularly during extended ...storage under inappropriate conditions. The phenomenon is governed by endogenous proteases, both digestive and muscle proteases. Proteases present in the gastrointestinal tract that leach out to muscle tissue can induce proteolysis of myofibrillar and collagenous proteins. Furthermore, the muscle proteins present in gels fabricated from fish or shellfish meat also encounter degradation during thermal processing. Endogenous heat‐activated proteases strongly bind to muscle proteins and are activated during heating, thereby degrading myofibrillar proteins, which are abundant in muscle tissue. This deterioration of the proteins directly leads to a weakened gel with poor water‐holding capacity. Both cysteine and serine proteases are responsible for the degradation of myofibrillar proteins in several aquatic animals. Effective pretreatment of fish and shellfish, as well as the use of food‐grade protease inhibitors (PIs), have been implemented to inactivate endogenous muscle and digestive proteases. For this review, proteolysis of muscle proteins and its control by food‐grade PIs are revisited. Improved and effective lowering of proteolysis should be gained, thereby maintaining the quality of fish and their products.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Crustaceans, especially shrimp, prawn, crab and lobster are economically important species with high market value because of their high demand. Nevertheless, crustaceans are perishable with a short ...shelf-life. It is prone to deterioration after capture, particularly during handling, processing and storage. Melanosis or black spot development in crustaceans is one of the most serious problems, causing the adverse impact on sensory properties and consumer acceptability. To conquer such a problematic deterioration, sulfiting agents and their derivatives are extensively applied as antimelanosis agent. Nevertheless, those chemicals mostly cause the allergy and severe disturbances for some asthmatic patients. As a consequence, the novel and safe alternatives from natural sources, especially plant polyphenols with anti-melanosis activity, can be used to maintain quality and prevent melanosis in crustaceans.
This review covers mechanism and factors affecting undesirable melanosis occurring in crustaceans mediated by polyphenoloxidase (PPO). This review also focuses on the recent findings on the new PPO inhibitors and their applications to control melanosis in crustaceans. The uses of plant polyphenols in combination with certain processing techniques are revisited.
Plant polyphenols can serve as PPO and melanosis inhibitor in crustaceans. Plant polyphenols appear to be promising alternatives to sulfiting agents. Apart from serving as melanosis inhibitor, plant polyphenols possessing antioxidant and antimicrobial activities, can help reduce quality losses and maintain the prime quality and market value of crustaceans throughout the supply chain.
•PPO is an enzyme causing undesirable melanosis or black spot in crustaceans.•Melanosis contributes to the adverse impact on consumer acceptability.•Plant polyphenols or extracts can serve as antimelanosis agents in crustaceans.•Plant polyphenols combined with appropriate techniques enhance melanosis prevention.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Antioxidative activities of different phenolic compounds (catechin, caffeic acid, ferulic acid and tannic acid) at various levels were determined by different assays. Among all the phenolic compounds ...tested, tannic acid exhibited the highest 2,2-diphenyl-1-picryl hydrazyl (DPPH) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities and ferric reducing antioxidant power (FRAP). Nevertheless, catechin showed the highest metal chelating activity (
P
<
0.05), whereas caffeic acid had the highest lipoxygenase (LOX) inhibitory activity (
P
<
0.05). The impact of different phenolic compounds at a level of 100
mg/l on lipid oxidation of menhaden oil-in-water emulsion and mackerel mince was investigated. Tannic acid showed the highest efficacy in retardation of lipid oxidation for both model systems as evidenced by the lower peroxide value (PV), conjugated diene (CD) and thiobarbituric acid-reactive substances (TBARS) values. This was also related with the lower non-heme iron content in tannic acid treated samples. Tannic acid was therefore considered as the most potential natural antioxidant for controlling oxidation of fish oil-in-water emulsion and fish mince, whereas ferulic acid seemed to possess the lowest preventive effect on lipid oxidation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The effect of modified atmosphere packaging (MAP) on the quality changes of Pacific white shrimp (
Litopenaeus vannamei) treated with or without green tea extract (1
g/L; GTE) in combination with or ...without ascorbic acid (0.05
g/L; AA) during refrigerated storage of 10
days was investigated. Shrimp without treatment stored under MAP had lowered psychrotrophic bacteria, enterobacteriaceae and H
2S-producing bacteria count (
P
<
0.05) but similar lactic acid bacteria count (
P
>
0.05), in comparison with shrimp stored in air (control). The coincidental lowered rate of increase in pH, total volatile base (TVB) content and thiobarbituric acid reactive substances (TBARS) were obtained in shrimp stored under MAP (
P
<
0.05). However, MAP slightly lowered melanosis formation and improved likeness score to some extent. When shrimp were treated with GTE and stored under MAP, the lower microbiological and chemical changes as well as the lowest melanosis formation were observed, compared to shrimp kept under MAP without treatment and the control (
P
<
0.05). GTE treatment in combination with MAP could retard chemical changes and melanosis formation, regardless of AA incorporation (
P
>
0.05). Nevertheless, GTE in combination with AA had higher inhibition on microbial growth and yielded the shrimp with higher likeness, compared with the other treatments (
P
<
0.05). Therefore, shrimp treated with GTE in combination with AA prior to MAP had the lowest losses in quality during refrigerated storage.
► MAP alone did not inhibit melanosis formation in Pacific white shrimp. ► Treatment of shrimp with GTE prior to MAP retarded quality changes during refrigerated storage. ► GTE with AA maximized the shelf-life of shrimp and maintained sensory property effectively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Lipid oxidation is the principal cause of quality loss in seafood, which is known to contain high amounts of polyunsaturated fatty acids. Such quality deterioration, associated with the development ...of off‐flavor as well as lowering of nutritive value, can be retarded by incorporation of additives having antioxidative properties. The use of synthetic antioxidants has long been practiced in retarding lipid oxidation. However, due to the potential health concerns of synthetic antioxidants, polyphenolic compounds, which are found in different plants and their manufactured by‐products, have been used as an alternative natural antioxidants to retard lipid oxidation in different seafood systems. Both pure phenolic compounds and crude plant phenolic extracts have been successfully used in delaying oxidation in fish muscle, fish oil, and fish oil‐in‐water emulsions. This article reviews in detail the phenolic antioxidants and their natural sources as well as focuses on the role of pure phenolic compounds and crude plant phenolic extracts on the prevention of lipid oxidation in different seafood systems.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•Seafood peptides could prevent the formation of ice crystal, leading to structural stabilisation of myofibrils.•Fish myofibrillar proteins, and especially myosin, had greater thermostability in the ...presence of seafood peptides.•Peptides could prevent the displacement of water molecules between the different muscle compartments during frozen storage.•The chain length of peptides is a determinant factor in unfolding and reorientation around oil droplets.
Seafoods have served as a significant source of lipids and proteins for human requirements. However, they are prone to chemical deterioration, especially oxidation and quality loss during storage and processing, associated with the development of off-odours/flavours and loss of nutritive value. Antioxidants have been used widely to prevent lipid oxidation, while cryoprotectants are known to retard protein denaturation of seafoods during the extended frozen storage. Due to possible toxicity and carcinogenic effects of synthetic antioxidants and sweetness of particular cryoprotectant, the natural and safe additives, derived from seafood origin have gained increasing attention. Peptides, mostly derived from processing by-products, have been demonstrated to exhibit antioxidative and cryoprotective effects in seafoods. This article revisits the antioxidative and cryoprotective effects of seafood-derived peptides for their potential as bifunctional ingredients to prevent lipid oxidation and protein denaturation in different seafood systems.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Effects of ferulic acid (FA) on polyphenoloxidase (PPO) and the quality changes of Pacific white shrimp (
Litopenaeus vannamei) during iced storage for 10
days were investigated. Both FA and ...oxygenated FA (OFA) with different concentrations (0.1%, 0.5%, 1% and 2% (w/v)) showed PPO inhibitory activity in a dose dependent manner. FA was generally more effective in PPO inhibition than was OFA. Based on activity staining, white shrimp PPO with an apparent molecular weight of 210
kDa was inhibited by FA. When whole shrimps were treated with FA solution with concentrations of 1% or 2% and stored in ice for up to 10
days, the increase in psychrophilic and mesophilic bacterial count were retarded, in comparison with the control and those treated with 1.25% sodium metabisulphite (SMS). The coincidental lower rates of increase in pH and total volatile base content were obtained. Additionally, shrimps treated with 2% FA possessed the lowest peroxide value and thiobarbituric acid reactive substances (TBARS) value during the storage. After 10
days of storage, shrimps treated with 2% FA had the lower melanosis score and higher score for colour, flavour and overall likeness, compared with the control and SMS treated shrimps (
P
<
0.05).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Chemical and microbiological deteriorations are principal causes of quality loss of fish and fish products during handling, processing, and storage. Development of rancid odor and unpleasant flavor, ...changes of color and texture as well as lowering nutritional value in fish can be prevented by appropriate use of additives. Due to the potential health hazards of synthetic additives, natural products, especially natural antioxidants and antimicrobial agents, have been intensively examined as safe alternatives to synthetic compounds. Polyphenols (PP) are the natural antioxidants prevalent in fruits, vegetables, beverages (tea, wine, juices), plants, seaweeds, and some herbs and show antioxidative and antimicrobial activities in different fish and fish products. The use of phenolic compounds also appears to be a good alternative for sulphiting agent for retarding melanosis in crustaceans. Phenolic compounds have also been successfully employed as the processing aid for texture modification of fish mince and surimi. Thus, plant polyphenolic compounds can serve as potential additives for preventing quality deterioration or to retain the quality of fish and fish products.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Physico-chemical and gelling properties of agar extracted from Gracilaria tenuistipitata as affected by alkaline pretreatments using NaOH and KOH at various levels (3–7%, w/v) were investigated. ...Yield of native agar was 17.1%, whilst those of agars pretreated with NaOH and KOH ranged from 23.6% to 26.1%. Agar with alkaline pretreatment generally showed the better gelling property as evidenced by higher gel strength, gelling, melting temperatures and viscosity with coincidentally increased 3,6-anhydrogalactose (3,6-AG) content than did native agar. Additionally, native agar had a higher sulphate content with lower syneresis (P < 0.05) than those with alkaline pretreatment. Regardless of alkaline concentration, NaOH used for pretreatment rendered agar with a higher quality, compared with KOH. Agar (1.5%, w/v) pretreated with 5% NaOH exhibited the highest gel strength (482 g/cm2) with high yield (25.3%). The decrease in total sulphate content and the increase in 3,6-AG content were observed in agar having 5% NaOH pretreatment as determined by FTIR spectroscopy. Finer and more compact network with smaller pores was visualised in gel from agar with 5% NaOH pretreatment. Therefore, the appropriate pretreatment by using 5% NaOH could increase yield and improve the gelling property of agar from G. tenuistipitata harvested from the lake of Songkhla, Thailand.
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•Alkaline pretreatment before extraction enhanced yield and gel property of agar from Gracilaria tenuistipitata.•Alkaline pretreatment rendered agar with higher gelling and melting temperature.•NaOH used for pretreatment yielded agar with higher desulphation than did KOH.•Pretreatment using 5% NaOH was recommended for agar production.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Gelatin was extracted from the skin of splendid squid (Loligo formosana) at different temperatures (50, 60, 70 and 80 °C) with extraction yield of 8.8%, 21.8%, 28.2%, and 45.3% (dry weight basis) for ...G50, G60, G70 and G80, respectively. Gelatin from the skin of splendid squid had a high protein content (∼90%) with low moisture (8.63–11.09%), fat (0.22–0.31%) and ash contents (0.17–0.68%). Gelatin extracted at higher temperature (G80) had a relatively higher free amino group content than gelatin extracted at lower temperatures (G50, G60 and G70) (P < 0.05). All gelatins contained α- and β-chains as the predominant components. Amino acid analysis of gelatin revealed the high proline and hydroxyproline contents for G50 and G60. FTIR spectra of obtained gelatins revealed the significant loss of molecular order of the triple-helix. The gel strength of gelatin extracted at lower temperature (G50) was higher than that of gelatins extracted at higher temperatures including G60, G70 and G80, respectively. The net charge of G50, G60, G70 and G80 became zero at pHs of 6.84, 5.94, 5.49, and 4.86, respectively, as determined by zeta potential titration. Gelatin extracted at higher temperature (G80) had the lower L* value but higher a* and b* values, compared with those extracted at lower temperatures (P < 0.05). Emulsion activity index decreased, whilst emulsion stability index, foam expansion and stability increased as the concentration (1–3%) increased (P < 0.05). Those properties were governed by extraction temperatures of gelatin. Thus gelatin can be successfully extracted from splendid squid skin using the appropriate extraction temperature.
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► Extraction of gelatin from squid skin at higher temperature increased the yield. ► Higher extraction temperature enhanced the hydrolysis of gelatin. ► Gelatin extracted at high temperature had the lower functional properties.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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