Melanosis In Shrimp Research Articles

Efficient pectin recovery from sugar beet pulp as effective bio-based coating for Pacific white shrimp preservation

This study demonstrates the valorization of sugar beet pulp (SBP)-derived pectin to produce bio-based coatings for shrimp preservation. Pectin extraction was assessed at varying temperatures and extraction times to achieve tailored properties (high methoxyl-pectins, degree of esterification-DE >79.0 %) leading to 11.5 % extraction yield, 78.1 % galactouronic acid content and 80 % DE at optimal conditions (pH 1.5, 80 °C, 2 h). Pectin-based coatings supplemented with ascorbic acid (AA) (0.5–2.0 %) led to organoleptically acceptable shrimps with significantly lower total color differences during 28-days of storage, compared to uncoated and pectin-coated counterparts. AA-based coatings delayed shrimp melanosis, expressed as reduced polyphenoloxidase activity (48–86 %). Rich-in-holocellulose solids derived after pectin extraction were used for bacterial cellulose (BC) production, pinpointing the SBP potential as a multi-purpose feedstock. Fed-batch fermentation enhanced BC concentration (by 110 %) and productivity (1.6-fold higher) compared to batch-cultures. Pectin produced within a SBP-based biorefinery could be applied as bio-based coating with food packaging potential.

Effectiveness of a formulation based on Ocimum gratissimum essential oil and cashew gum as inhibitors of quality loss and melanosis in shrimp

In this study, two nanoemulsions were formulated with essential oil (EO) of Ocimum gratissimum with (EON) or without (EOE) cashew gum (CG). Subsequently, inhibition of melanosis and preservation of the quality of shrimp stored for 16 days at 4 ± 0.5 °C were evaluated. A computational approach was performed to predict the system interactions. Dynamic light scattering (DLS) and atomic force microscopy (AFM) were used for nanoparticle analysis. Gas chromatography and flame ionization detector (GC-FID) determined the chemical composition of the EO constituents. Shrimps were evaluated according to melanosis's appearance, psychrotrophic bacteria's count, pH, total volatile basic nitrogen, and thiobarbituric acid reactive substances. EON exhibited a particle size three times smaller than EOE. The shrimp treated with EON showed a more pronounced sensory inhibition of melanosis, which was considered mild by the 16th day. Meanwhile, in the other groups, melanosis was moderate (EOE) or severe (untreated group). Both EON and EOE treatments exhibited inhibition of psychrotrophic bacteria and demonstrated the potential to prevent lipid oxidation, thus extending the shelf life compared to untreated fresh shrimp. EON with cashew gum, seems more promising due to its physicochemical characteristics and superior sensory performance in inhibiting melanosis during shrimp preservation.

Chitosan Decelerates Melanosis in Shrimp: A Novel Technique for Visual Quality Assessment Using Digital Image Analysis

The study aimed to determine the effects of chitosan, sodium metabisulfite, and citric acid against melanosis, which causes significant economic losses during the storage of shrimps. For this purpose, two different types of chitosan were extracted from tiger prawn shell wastes. The extracted chitosan was characterized by viscosity, FT-IR, XRD, SEM imaging, and color analyses. Prevention of melanosis formation was investigated by testing chitosan, sodium metabisulfite, and citric acid. To achieve this, fresh deep-water pink shrimp samples immersed in different solutions were stored for 12 days at 4℃. Melanosis formation in the samples was observed via color measurement, sensory evaluation, and image analysis. According to the results of the research, the deacetylation degrees of chitosans were found to be 99.50 and 89.51% and 76.31 and 78.24% by two different methods, respectively. Viscosities were measured as 0.34 and 4.17 cSt, respectively. Regarding the color parameters, the L* values were 83.68 and 78.94, a* values were 0.55 and 2.71, and b* values were 10.33 and 13.85, respectively. According to the sensory evaluation conducted throughout the study, melanosis formation was observed in all groups starting from the 6th day. On the 8th day, the control groups exceeded the acceptability threshold, and on the 12th day, melanosis formation spread throughout the body in all groups. The sensory evaluation results were supported by the color measurement and image analysis implemented for the first time in this study. The present study’s results showed that chitosan obtained from shellfish wastes decelerates melanosis formation as an alternative to commercially used chemicals.

Expression of polyphenol oxidase of Litopenaeus vannamei and its characterization

Polyphenol oxidase (PPO) plays a critical role in decrement of shrimp quality. To obtain active PPO and elucidate its enzymatic properties, PPO from Litopenaeus vannamei (Lv-PPO) was cloned, expressed in E. coli and purified by affinity column chromatography. The Lv-PPO gene was 2076 bp in length encoding 691 amino acids. The recombinant Lv-PPO (rLv-PPO) with a molecular mass of ∼85.0 kDa was successfully expressed and its sequence was verified by LC-MS/MS. rLv-PPO was biologically active with an optimal temperature of 40℃ and an optimal pH of 6.0. Metal ions Cu2+ and Zn2+ altered the activity of rLv-PPO by influencing its secondary and tertiary structures. rLv-PPO showed catalytic activity towards l-Dopa and catechol. A specific polyclonal antibody against rLv-PPO was prepared. Western blot analysis revealed that PPO levels were highest in hemolymph, followed by telson, carapace, and eyestalk. Expression of rLv-PPO will assist future studies on the mechanism in shrimp melanosis.

Ginger oil and lime peel oil loaded PBAT/PLA via cast-extrusion as shrimp active packaging: Microbial and melanosis inhibition

Biodegradable active packaging for shrimp was produced via cast sheet extrusion of poly (butylene adipate terephthalate) and poly (lactic acid) (PBAT/PLA) at different ratios, incorporating ginger oil (GO) and lime peel oil (LPO). Surface chemistry, mechanical and barrier properties, volatile mass fraction, and antimicrobial activities were investigated. Microbial growth and melanosis of packaged shrimp were monitored. Gas chromatography-mass spectrometry indicated major volatile components of LPO and GO as D-limonene (40.55%) and L-zingiberene (19.85%), respectively. Essential oil loading improved polymer compatibility via C-H bonding and modified the polymer crystallinity, leading to improved film flexibility but reduced tensile strength. GO incorporation showed greater release of volatile mass fraction from the film matrix than LPO, with increased oxygen permeability and water contact angle. High PBAT film (PBAT70/PLA30) allowed greater release of essential oil than high PLA film (PBAT30/PLA70), with higher antimicrobial activity against Bacillus cereus. Film containing LPO was more effective in inhibiting microbial growth, while film containing GO showed superior prevention of melanosis in packaged shrimp. A linear correlation was found between microbial growth and degree of melanosis in shrimp packaged in PBAT/PLA packaging containing GO and LPO. Both LPO and GO effectively enhanced film functional properties and showed promise for seafood packaging with different mechanisms of ameliorating product bacterial degradation.

Effect of chitosan-coated Ulva intestinalis sulfated polysaccharide nanoliposome on melanosis and quality of Pacific white shrimp during ice storage

This study investigates chitosan coating containing nanoliposome of Ulva intestinalis sulfated polysaccharide, its effect on melanosis, as well as the quality of Pacific white shrimp during 20 days of storage in ice. The sulfated polysaccharide was extracted from Ulva intestinalis (USP), and its impact on the shrimp's polyphenol oxidase (PPO) enzyme inhibition in different concentrations was measured. The optimum concentration of USP with the highest inhibition percentage was selected and used. USPs were loaded in nanoliposome or coated in chitosan then shrimps were immersed in these coatings. 1.5 % USP showed the highest inhibitory effect of PPO enzyme after 1 and 3 min with values of 63.03 % and 48.74 %. The melanosis of shrimps with different types of USP coating was significantly lower than the control. The lowest color change (ΔE), total viable counts (TVC) bacterial, TVN content, and weight loss were achieved in the Ch-USP treatment. The highest sensory score was found in the Ch-N-USP treatment. This coverage delayed the increase of psychrophilic bacteria (PBC) and chemical tests (TBA, FFA, and PV). Therefore, Ch-USP and Ch-N-USP treatments can be used as a natural substitute for sodium metabisulfite to increase the shelf life and shrimp quality during ice storage.

The Effect Of Princess Shame Leaves Ethanol Extract On Vitiligo

Background: Vitiligo is a skin disease caused by the destruction of melanocytes with depigmented macular characteristics, multifactorial predisposing factors, and precipitating factors such as trauma, sunburn, stress, and systemic disease. Mimosa Pudica has bioactive compounds that are efficacious for healing wounds, repairing cell tissue, stopping bleeding, asthma, diabetes, jaundice, leprosy, hydrocele, hemorrhoids, fistulas, scrofula, and conjunctivitis. Method: Based on the results of several studies, the technique of collecting & analyzing the cream of Mimosa Pudica leaf extract was by evaluating the cream of the Mimosa Pudica leaves, testing the pH by dissolving the cream product which was diluted using aquadest and then measured with a pH meter. The production of the Mimosa Pudica leaf extract was done by maceration using 96% ethanol. Results: Mimosa Pudica extract succeeded in preserving salak fruit, increasing the regeneration and proliferation of liver cells, overcoming hypopigmentation skin disease, and also inhibiting melanosis in shrimp. Conclusion: Mimosa Pudica (Mimosa pudica L.) The five parts of the plant (i.e. panchang) - leaves, flowers, stems, roots, and fruit belong to the category of powerful antioxidants used as medicine in ethnomedical systems of care.

Effective Treatment of Curry (Murraya koenigii) and Moringa (Moringa oleifera) Leaves Extracts on Melanosis of Pacific White Shrimp (Litopenaeus vannamei) during Chilled Storage

ABSTRACT This study investigated the treatment effect of curry leaves extract (CLE) and moringa leaves extract (MLE) on the melanosis of Pacific white shrimp during 15 days of chilled storage. These extracts have a high number of phytochemicals that have various therapeutic potentials. In this study, shrimp samples were divided into 4 groups; 1% CLE treated, 1% MLE treated, 1:1 (CLE+MLE) treated and control, and stored for 15 days. Biochemical indices and microbiological analysis wereperformedat 3 days interval. In this study, both extracts showed significant results on chemical indices, but highest qualitative results were obtained by the 1:1 (CLE+MLE) treated group. Among the treated groups, 1:1 (CLE+MLE) had a greater effect on microbial spoilage in comparison with the control group. This study revealed that CLE and MLE contain a variety of phytochemicals withdifferent properties that could be utilized as a natural substitute for synthetic antimelanosic agents used to control melanosis in shrimp.

Inhibition of Melanosis in Whiteleg Shrimp (Litopenaeus vannamei) during Refrigerated Storage Using Extracts of Different Avocado (Persea americana Mill.) By-Products.

Melanosis in shrimp usually leads to reduction in its shelf life and quality, which causes a significant loss in economic value of shrimp products. This study reports potential applications of nine ethanolic extracts of by-products, i.e., peel and/or seed from three Vietnamese avocado varieties as effective inhibitors of melanosis in whiteleg shrimp. Six out of nine shrimp samples treated with the prepared extracts (0.025%, w/v) reduced melanosis and lipid oxidation more significantly as compared to those treated with sodium metabisulfite (SMS, 1.25%, w/v) and control groups (treated with water) during 8-day storage at 4°C (P<0.05). These six extracts had mean gray values ranging from 47.0±0.7 to 57.3±0.4% were lower than those treated with SMS (mean gray of 39.8±0.4%). The inhibition of melanosis and lipid oxidation in shrimp for these extracts could be attributed to their high content of polyphenols [total phenolic content (TPC) from 44.5±1.1 to 144.7±1.9 mg gallic acid equivalents/g dried weight] and strong antioxidant activities [including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power (FRAP), and tyrosinase enzyme inhibition]. Pearson statistical analysis showed strong correlation for melanosis inhibition to TPC and DPPH scavenging (r>0.80) followed by tyrosinase inhibition and FRAP (r>0.50). The findings obtained from this study suggest potential utilization of avocado by-product extracts as safe and cheap natural alternatives to traditional sulfites for anti-melanosis and shelf life extension of whiteleg shrimp.

Prevention of quality loss and melanosis of white leg shrimp by Sargassum horneri extracts

PurposeBeing interested in developing a natural preservative for the prolongation of shrimp shelf life, this study aims to evaluate the Sargassum horneri extracts for their antioxidant effect, copper reducing power, copper chelating activity and polyphenol oxidase (PPO) inhibitory activity, as well as explored their potential preservative activity in white leg shrimp.Design/methodology/approachThe antioxidant properties of Sargassum horneri 75% ethanol aqueous extracts were measured by 2,2-diphenyl-1-picryl hydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP) and PPO inhibitory activity. Sample III displayed the highest antioxidant activity, PPO inhibitory activity, copper reducing power and copper chelating activity, so it was selected for further studying its impact on shrimp's quality changes such as pH value, total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), melanosis and sensory score during storage at 4°C.FindingsAmong all three samples, sample III containing 49.88% total phenolic contents was selected for the further study on the prevention of quality loss and melanosis of shrimp, because it yielded the highest antioxidant activity, PPO inhibitory activity, copper reducing power and copper chelating activity than the other two samples (samples II and IV). It was found that shrimp treated with 0.2% sample III had the lowest melanosis scores throughout the storage (p &lt; 0.05). During ten days of storage at 4°C, shrimp treated with 0.2% sample III had a higher score in sensory properties (color, segments, texture and odor), compared with the control, 0.1% kojic acid and 0.1% sample III treated shrimp (p &lt; 0.05). The results indicated that the treatment of shrimp with 0.2% sample III could extend the shelf life to eight days at 4°C.Social implicationsThe extracts of Sargassum horneri displayed potent PPO inhibition, antimicrobial and antioxidant properties. Importantly, the 75% extracts of Sargassum horneri could extend the shelf life. Considering these results, the extracts of Sargassum horneri may be used as natural preservatives in the food industry after further evaluation of their other properties such as toxicity, as well as provide a choice target to source natural products intended for cosmetics.Originality/valueThe originality of this paper lies in the development and application of the extracts of edible algae. To extend the shelf life of seafood, the polyphenolic-rich extract of Sargassum horneri provided another possible selection.

Effects of ascorbic acid and erythorbic acid on melanosis and quality in different shrimp species

With this study, ascorbic acid and erythorbic acid were used for the first time to prevent melanosis in shrimp. Three shrimp species (Aristaeomorpha foliacea, Plesionika edwardsi and Melicertus hathor) were used. It was determined that melanosis scores were higher in the control groups. Combination of ascorbic acid and erythorbic acid with metabisulphite was found to be more effective in inhibiting of melanosis than the application alone. No significant differences were found between the groups in terms of TVB-N values. The TMA-N value of the control group was significantly higher than those of application groups. Ascorbic acid, Erythorbic acid and their combinations with sodium metabisulphite were found effective on inhibition of melanosis and quality changes in three shrimp species.Keywords: reducing agents; ascorbic acid; erythorbic acid; melanosis; quality; shrimp

Enzymatic characteristics of polyphenoloxidase from shrimp (Penaeus vannamei) and its inhibition by a novel hydroxypyridinone derivative.

Melanosis developed in shrimp (Penaeus vannamei) is mainly initiated by polyphenoloxidase (PPO), thus understanding of the characteristics of PPO in shrimp is important for controlling the melanosis of shrimp. The shrimp cephalothorax turns black most rapidly amongst all the tissues during the chilled storage. Crude PPO extracted from this cephalothorax has an optimal pH of 6.0 and an optimal temperature of 50°C. PPO is relatively stable under neutral and weak alkaline conditions (pH 5.5-9.0) and the temperature range of 25-35°C. The kinetic parameters K m and V max were recorded as 3.02mM and 54.3U/mg of protein, respectively, using L-Dopa as a substrate. The molecular weight of PPO was estimated as 200-220kDa by an activity staining test. A hydroxypyridinone derivative, 5-hydroxy-1-octyl-4-oxo-1,4-dihydropyridine-2-carbaldehyde O-ethyl oxime, was demonstrated to efficiently inhibit the PPO, indicating that this compound might find application as a shrimp preservative.

4-Hexylresorcinol 침지액 농도와 침지시간에 따라 새우의 갈변도 및 4-Hexylresorcinol 잔류량에 미치는 영향

껍질을 제거하지 않은 새우의 경우 10일 동안 저장하는 과정에서 갈변이 심각하게 진행된 것을 확인할 수 있었다. 갈변은 두흉부, 등껍질 그리고 꼬리 순서로 진행되었으며, 4-hexylresorcinol 침지액에 의해 갈변이 억제될 경우 꼬리, 등껍질 그리고 두흉부 순서로 억제되었다. 껍질을 제거하지 않은 새우의 경우 10, 20 mg/L 4-hexylresorcinol 침지액 농도에서 72시간 침지한 새우로부터 각각 1.36, 2.33 mg/kg의 잔류농도를 확인하였으며, 해외에서 규정하고 있는 최대잔류수준 이상의 4-hexylresorcinol이 검출되어 갈변억제 효과는 있었지만 사용방법으로 부적합한 것으로 나타났다. 껍질을 제거한 새우의 경우에는 가식부위가 직접 침지액에 침지되기 때문에 대부분의 새우에서 1 mg/kg 이상의 4-hexylresorcinol 잔류량이 확인되었으며, 껍질을 제거한 새우를 20 mg/L 4-hexylresorcinol 침지액에 72시간 동안 침지한 처리군에서 13.46 mg/kg으로 가장 높은 4-hexylresorcinol 잔류량이 확인되었다. 이러한 결과는 캐나다 및 중국뿐만 아니라 유럽에서 규정하고 있는 최대잔류수준을 초과함에 따라서 새우의 침지 조건으로 새우 껍질을 제거한 뒤 침지하는 방법은 적합하지 않은 것으로 판단되며, 갈변억제 효과는 20 mg/L 4-hexylresorcinol 침지액에서 24시간 동안 침지한 처리군에서 가장 높은 억제 효과를 나타내었다. 본 연구 결과 4-hexylresorcinol 침지액 농도와 침지시간에 따라 4-hexylresorcinol 잔류량 및 갈변억제 효과에 높은 상관관계를 나타내었으며, 규정에 제시되어 있는 최대잔류허용량을 초과하지 않고 효율적인 갈변억제 효과를 얻기 위한 방법으로는 껍질을 제거하지 않은 새우에서 20 mg/L 4-hexylresorcinol 침지액에서 24시간 동안 침지처리하는 방법이 가장 적절한 것으로 확인되었다.

Effects of Plant Extract-Sulphide Combinations on Melanosis Inhibition and Quality in Shrimp (Aristeus Antennatus)

In this study, shrimp (Aristeus antennatus) immediately after trawling was treated with plant extracts (rosemary and green tea), sodium metabisulphite solution, and their combinations. After dipping into the solutions, melanosis and selected quality changes of shrimp were investigated during the storage at 4°C. Plant extracts were found effective in delaying melanosis in shrimp. Combinations of sodium metabisulphite and plant extracts were found more effective than those groups separately treated with plant extracts. Plant extracts, sodium metabisulphite, and combinations showed lower trimethylamine and total volatile nitrogen values as compared to the control group. It is concluded that use of plant extracts decreased the need for sodium metabisulphite.

Standardization of sodium metabisulfite solution concentrations and immersion time for farmed shrimp Litopenaeus vannamei

Sodium metabisulfite is the main additive used in the prevention of melanosis in shrimp; however, it has currently been employed with great variation in concentration by producers. Thus, the aim of the present study was to determine the correlation between the concentration of the sodium metabisulfite solution and immersion time of the whole shrimp to obtain the concentration of sulfur dioxide (SO2) in the edible muscle of farmed shrimp (Litopenaeus vannamei) in accordance with the limit established by law. For this, solutions of sodium metabisulfite at different concentrations (1%, 2 %, 3 %, 4% and 5%) were prepared and samples of L. vannamei shrimp (100g) were immersed during 10, 20 or 30 minutes at temperature of 7°C. For all treatment assayed the concentration of SO2 was determined in the edible muscle of farmed shrimp (L. vannamei). The results show that for the conditions used in this study, the correlations were linear, with significant increase (P&lt;0.05) in the SO2 concentration in the edible muscle of shrimps both increasing sodium metabisulfite concentration as increasing immersion times, suggesting the immersion of shrimps in a 3% solution for a time of 13 minutes in order to obtain SO2 concentration of 100ppm in its edible muscle in accordance with Brazilian legislation

Comparación de tres metodologías para la captación de sulfitos en camarones tratados con metabisulfito de sodio

La industria acuícola en la zona sur pretende incrementar la comercialización de camarón entero en los mercados norteamericano y europeo, castigando fuertemente los camarones con melanosis o con residuos de sulfitos superiores a 100 ppm, respectivamente. La melanosis consiste en el desarrollo de una coloración negruzca en el exoesqueleto del camarón. El metabisulfito de sodio (MBS) inhibe la formación de melanosis. Para detectar residuos de sulfitos en camarones tratados con MBS se emplean los métodos de cintas colorimétricas, titulación con iodometría y titulación con Monier-Williams (M-W). Los objetivos del estudio fueron evaluar los métodos para detectar sulfitos en camarones tratados con MBS y determinar la cantidad de sulfitos detectados con el procedimiento M-W a diferentes tiempos de destilación. Se seleccionaron camarones de un estanque de producción, según las características de textura del exoesqueleto, que fueron sometidos a baños de 0.5 % y 1.0 % de MBS. También se determinaron las concentraciones de sulfitos y el desarrollo de melanosis durante ocho semanas de almacenamiento a -18°. El método de cintas colorimétricas no tiene precisión para detectar sulfitos en los camarones, el método M-W detectó más sulfitos que la iodometría (P&lt;0.004). Se encontraron correlaciones altamente significativas con el método M-W entre los sulfitos detectados después de cada tiempo de destilación (P&lt;0.001). Los camarones tratados con MBS mostraron una reducción de sulfitos a lo largo de ocho semanas de almacenamiento (P&lt;0.04). El método M-W mostró ser el más preciso en la detección de sulfitos. Según los resultados del ensayo, se puede acortar el tiempo de destilado en el método M-W para detectar adecuadamente los residuos de sulfitos en el camarón. Los camarones tratados con MBS presentaron menos melanosis (P&lt;0.02) que los no tratados durante ocho semanas de congelamiento. DOI: http://dx.doi.org/10.5377/rct.v0i14.1796 Revista Ciencia y Tecnología No. 14, junio 2014: 62-76

Application of ergothioneine-rich extract from an edible mushroom Flammulina velutipes for melanosis prevention in shrimp, Penaeus monodon and Litopenaeus vannamei

This report investigated the melanosis-inhibiting properties of crude water soluble extract from the base and fruiting body waste of an edible mushroom (Flammulina velutipes) containing 9.13±2.03mg/mL 2-thiol-l-histidine-betaine (ergothioneine, ESH). Immersion of live full-grown black tiger shrimp (Penaeus monodon) and Pacific white shrimp (Litopenaeus vannamei) in a 0.5% w/v solution of mushroom extract for 1h significantly decreased polyphenoloxidase (PPO) activity in shrimp hemolymph and expression of the prophenoloxidase (proPO) gene in hemocytes. Consequently, the development of melanosis in the treated shrimp during ice storage was prevented. Treatment with a 0.05% w/v solution of sodium sulfite and 4-hexyl-1,3-benzenediol had a similar effect. Enzyme assays showed that ESH is a non-competitive inhibitor. It is proposed that ESH possibly interacts directly with Cu2+ at the putative binding sites of PPO and proPO, based on copper-chelating activity analyses, thus preventing melanosis in the shrimp. This study indicated that application of ESH-rich F. velutipes mushroom extract from trimming waste is an effective natural alternative to synthetic melanosis-inhibiting agents to prevent postmortem melanosis in shrimp.

Edible Mushroom (Flammulina velutipes) Extract Inhibits Melanosis in Kuruma Shrimp (Marsupenaeus japonicus)

This study compared the potential of an aqueous extract of an edible mushroom (Flammulina velutipes) to prevent melanosis in cultured Kuruma shrimp (Marsupenaeus japonicus) with other antimelanosic compounds in vivo. The mushroom extract contained 9.1 mg/mL ergothioneine (ESH). Immersion of live full-grown shrimp in a 0.5% w/v solution of mushroom extract significantly reduced PPO activity in shrimp hemolymph. In addition, expression of the prophenoloxidase (proPO) gene decreased in hemocytes, suggesting that the extract blocked the activation of the proPO cascade. Consequently, the development of melanosis in the treated shrimp was significantly suppressed during ice storage. Treatment with a 0.05% w/v solution of sodium ascorbate and 4-hexyl-1,3-benzenediol had the same effect. In vitro experiments showed that ESH effectively inhibited PPO activity and activation of the proPO cascade in hemocyte lysate supernatant. This study suggests that in vivo application of F. velutipes mushroom extract is an effective natural alternative to synthetic antimelanosic agents to inhibit postmortem melanosis in shrimp. Practical Application: The extract of an edible mushroom (F. velutipes) containing ergothioneine can be a promising natural alternative to synthetic antimelanosic agents used to prevent postharvest melanosis in shrimp and other crustaceans. Furthermore, utilization of the mushroom trimmings could also help address the growing concerns on the disposal of such agricultural wastes and instead use it into a novel purpose as a source of antimelanosic and antioxidants for food and industrial application.

Effect of catechin and ferulic acid on melanosis and quality of Pacific white shrimp subjected to prior freeze–thawing during refrigerated storage

Melanosis of Pacific white shrimp ( Litopenaeus vannamei) subjected to freeze–thawing with different thawing methods and various cycles were monitored during subsequent refrigerated storage (4 °C) up to 4 days. Melanosis score was lower in Pacific white shrimp thawed at 4 °C, compared with that found in samples thawed at room temperature or using tap water. Polyphenol oxidase (PPO) activity increased as freeze–thaw cycles increased ( P < 0.05). Enhanced PPO activity was most likely associated with increased melanosis. Pacific white shrimp treated with catechin (0.05%, 0.1% and 0.2% (w/v)) or ferulic acid (1%, 2% and 3% (w/v)) and subjected to freeze–thawing with various cycles showed the retarded melanosis during the subsequent refrigerated storage of 4 days, compared with the control ( P < 0.05). Treatment of shrimp with both phenolic compounds could impede the growth of psychrophilic bacteria and the spoilage as evidenced by the lowered psychrophilic bacteria count and total volatile base content (TVB). Sample treated with 0.2% catechin or 3% ferulic acid also exhibited the retarded lipid oxidation during the subsequent refrigerated storage, compared with the control ( P < 0.05). Thus, either catechin or ferulic acid could be used as the potential additive to lower melanosis of shrimp with prior freeze–thawing.

Inhibition effects of grape seed extracts on melanosis formation in shrimp (Parapenaeus longirostris)

SummaryThe aim of this study was to investigate the effects of grape seed extracts on inhibition of melanosis in shrimp. Defatted grape seed powder was extracted using ethanol. Dipping solutions in five different concentrations (0, 2.5, 5.0, 10 and 15 g L−1) were prepared using grape seed extract and distilled water. The shrimps were dipped into the solutions and stored at 4 °C. Melanosis was investigated by sensory analysis and lightness, redness and yellowness values were measured by chromometer during the storage for 3 days. According to the results, grape seed extracts showed inhibition effect on the formation of melanosis. The best results were obtained with the solution of 15 g L−1.