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1.
ABSTRACT

This work aimed to evaluate the physicochemical and functional properties of proteins recovered from whitemouth croaker (Micropogonias furnieri) and Argentine anchovy (Engraulis anchoita) residues obtained by the process of acid solubilization using HCl at pH = 2 and alkaline solubilization using NaOH at pH = 12 and isoelectric precipitation (pH = 5.5). The proximate composition and functional properties were determined. The solubilization and water holding capacity (WHC) of the recovered protein were studied in the pH range of 3, 5, 7, 9, and 11. The high protein content and lowest lipid reduction presented by the protein recovered from the whitemouth croaker residue and obtained by the acid solubilizing process was 97.1 and 98.4%, respectively. The maximum solubilized protein was at pH 3 and 11, and the minimum solubilized protein was at pH 5 for both species. The greater ability to retain oil was observed for the alkaline solubilization process (8.3 and 7.3). The lower WHC was at pH 5. The acid and alkali residue concentrates of the whitemouth croaker presented higher WHC at pH 3 and 11. These proteins can be used in preparing edible films and have been used to produce bioactive compounds for supplements or functional ingredients.  相似文献   

2.
ABSTRACT

Proteins have been used extensively because of their relative abundance, nutritional qualities, and film-forming ability with a good structural integrity and mechanical properties. This study investigated the effects of protein isolate and glycerol concentration and pH on the properties of protein films obtained from Whitemouth croaker (Micropogonias furnieri) residues. The films were evaluated for mechanical properties, thickness, water solubility, water vapor permeability (WVP), and morphological properties. The lowest water solubility of the films occurred at low pHs and low glycerol concentrations. The films had high elongation and higher tensile strength when prepared with higher concentrations of protein isolate, lower concentrations of glycerol, and at lower pHs. The WVP and thickness of the films had a low correlation coefficient. The films were rough and had irregular surfaces. These results indicated that protein isolates from fish of low commercial value can be used as a component of new polymeric films for packaging. However, more studies are needed to assess their barrier action against oxygen, thermal behaviors, and their performance in different types of packaging.  相似文献   

3.
ABSTRACT

Grouper bone gelatin films were prepared along with chitosan (GC), clove (GL), and pepper (GP) essential oils and examined for their mechanical, barrier, and antimicrobial properties. GC films had a high tensile strength (TS) of 28 MPa, and GL and GP films had a high elongation at break (EAB) of 162 and 166%, respectively. Water solubility and water vapor transmission rate (WVTR) were low in GL films. All the films exhibited inhibitory activities against Staphylococcus aureus, Aeromonas hydrophila, and Listeria monocytogenes. Vacuum-packed fish steaks coated with GC and GL film extended the shelf life from 4 days to 8 days at 4ºC.  相似文献   

4.
The effect of adding different concentrations of freeze-dried (FD-WCPH) and spray-dried (SD-WCPH) whitecheek shark (Carcharhinus dussumieri) protein hydrolysate to the physical properties (solubility in water, contact angle, water vapor permeability, and opacity), mechanical properties (tensile strength, elongation at break, and elastic modulus) and color of gelatin films has been studied. The results showed that FD-WCPH and SD-WCPH led to an increase in water solubility and water vapor permeability and a decrease in contact angle and opacity of gelatin films (P < 0.05). Fish protein hydrolysate concentration showed a linear relation with elongation at break and an inverse relation with the tensile strength and elastic modulus of the films (P < 0.05).  相似文献   

5.
以有限数据评估方法为基础的海州湾渔业管理策略评估   总被引：1，自引：0，他引：1  
孙铭  张崇良  李韵洲  徐宾铎  薛莹  任一平 《水产学报》2018,42(10):1661-1669
实验以计算机模拟的管理策略评价方法为基础,以海州湾海域的银鲳、小黄鱼、大泷六线鱼和长蛇鲻为例,对基于数据有限方法的管理策略进行了分析评价。模拟结果显示,基于体长的管理策略能够在产量和避免过度捕捞间取得较好的权衡,其管理效果优于基于捕捞努力量的管理策略。模拟结果显示,银鲳和大泷六线鱼处于过渡捕捞状态;小黄鱼种群规模具有较大波动和不确定性;长蛇鲻种群未遭受过度捕捞。研究表明,基于有限数据评估方法的管理策略可以有效避免潜在的过度捕捞,提升遭受过度捕捞群体的产卵群体生物量规模,具有较好的可持续性,并能维持可观的产量,在我国具有广泛的运用前景。  相似文献   

6.
ABSTRACT

In order to enhance antimicrobial activity of the film, zinc oxide (ZnO) nanoparticles were incorporated in gelatin/chitosan composite film, and the physical-mechanical properties were investigated. The film-forming solution of gelatin/chitosan/ZnO films showed increased gel strength (GS), elastic modulus (G’), and viscous modulus (G’’) compared to that of the Control. Fish gelatin/chitosan/ZnO films showed lower water vapor permeability (WVP), higher glass transition temperatures (Tg), and antibacterial activities against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Vibrio parahemolyticus. Fourier transform infrared spectra (FTIR) and microstructure studies indicated gelatin, chitosan, and ZnO interactions determined the properties of the composite film.  相似文献   

7.
ABSTRACT

This work evaluated the technological, bacteriological, and sensorial quality of cookies produced with increasing levels (0%, 10%, 20%, 30%, and 40%) of mechanically separated meat flour from tilapia (MSMF) to replace rice flour (RF) in order to identify the optimal level without compromising the overall quality of the product. The cookies were analyzed for expansion index (EI), specific volume (SV), hardness, color, water activity (aw ), coagulase-positive staphylococci, coliforms at 45°C, Salmonella spp., and sensory acceptance. The inclusion of MSMF affected (P < .05) some characteristics such as EI, SV, aw , hardness, and color (L*, a*, b*), but all formulations met the legal bacteriological standards. Cookies with 20% substitution of RF by MSMF presented 58.82% carbohydrates, 18.53% proteins, and 11.31% lipids, and was the most accepted (P < .05); 51% of consumers rated it with a score of six or higher (above I liked slightly). It is concluded that the substitution of 20% of RF by MSMF can be used for nutritional enrichment of widely consumed conventional products.  相似文献   

8.
Abstract

The effects of controlled reproduction of African catfish, Clarias gariepinuswere investigated in an experiment with carp pituitary (at the dose 4 mg/kg body weight) or Ovopel (1 pellet/kg body weight) used as ovulation stimulators. The application of the synthetic stimulator led to the significantly (P≤0.01) greater weight of eggs (expressed in grams and as percentage of female body weight) and to the significantly (P≤0.05) higher quality of eggs after 24-hour incubation as compared with the hypophysation effects. Two categories of females were used in the experiment, i.e., light (mean body weight of 3.75 kg) and heavy (mean body weight of 8.86 kg) fish. The results show that a significantly (P≤0.01) greater weight of eggs (expressed in grams) was obtained from heavier females. The quality of eggs expressed as the percentage of live embryos after 12- and 24-hour incubation was significantly (P≤0.01 and P≤0.05, respectively) higher for lighter females. The higher weight of obtained eggs and their better quality after Ovopel stimulation compared to the weight and quality of eggs obtained after hypophysation allow for the recommendation of this ovulation stimulator for the fish species investigated.  相似文献   

9.
In the present study, the physicochemical and mechanical properties of films made from anchovy (Engraulis encrasicholus) by-product proteins (ABPs) were characterized as a function of protein (3, 4, and 5%) and glycerol (30, 40, 50, and 60%) concentration. In particular, the thickness, color, transparency, water vapor permeability (WVP), solubility, oxygen permeability (OP), and mechanical properties of the films were measured, and generally, these properties were affected by both protein and glycerol concentration. The thickness, redness, WVP and solubility values of films increased, while their lightness and yellowness values decreased as protein concentration increased. Furthermore, lightness, yellowness, and elongation at break (EAB) values were found to increase at higher glycerol concentrations within ABP films, whereas tensile strength (TS) and elastic modulus (EM) values decreased. ABP films became more transparent with increase of glycerol concentration and decrease of protein concentration. The OP values of all films decreased depending on protein and glycerol concentration. The techniques for order performance by similarity to ideal solution (TOPSIS) method was used to determine optimum protein and glycerol concentrations. According to this method, an edible film containing 4% protein and 40% glycerol was the best film with a C value of 0.6665.  相似文献   

10.
Pectin is a promising candidate to be employed as binder for manufacturing pellets for crayfish feeding. In this study, the gelling properties of different types of pectin and their effects on Cherax quadricarinatus performances have been analysed. Pectins with different degree of esterification from apple and citrus were screened to select those with the best gelling properties to be employed in pellet manufacturing. Three pectins were selected: low esterification degree apple pectin (LEAP), low esterification citrus pectin (LECP) and high esterification degree apple pectin (HEAP). Scanning electron microscopy analysis, nutrient leaching and water uptake indicated that LEAP showed the best aggregating properties, followed by LECP and HEAP pellets. Cherax quadricarinatus performances were affected by the pectin type, with redclaw fed LEAP pellets showing the highest (P < 0.05) growth rate and amylase activity (P < 0.05) in the gastrointestinal tract. Altogether these results indicate that LEAP can be considered an excellent binder for feed pellets due to its gelling properties and its efficacy to improve growth and stimulation of digestive enzyme activity.  相似文献   

11.
Abstract

β-hydroxy-b-methylbutyrate (HMB), a leucine catabolite, has been shown to cause increased disease resistance and growth in animal production. A vaccine produced from formalin killed bacteria and concentrated extracellular products of the ARS-98-60 Streptococcus iniae isolate has been used for the prevention of streptococcal disease in Nile tilapia, Oreochromis niloticus. In the present study, the effects of feeding HMB were determined in tilapia vaccinated by intraperitoneal (IP) injection of the S. iniaevaccine or unvaccinated (controls). Nile tilapia were fed diets containing either 0, 12.5, 25, or 50 mg HMB/kg diet for 14 days. The mean daily growth rate and feed efficiency showed no significant (P> 0.05) differences between the treatment groups. Dietary HMB supplementation did not enhance antibody production in unvacci-nated Nile tilapia following challenge. Dietary HMB supplementation did not enhance the survival of vaccinated Nile tilapia following challenge injection with 1 X108 CFU of S. iniae.  相似文献   

12.
ABSTRACT

The effects of melanin-free ink (MFI) and pre-emulsification on gel properties and stability of bigeye snapper surimi gel fortified with seabass oil during refrigerated storage of 10 days were studied. Lipid oxidation as determined by peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) of surimi gel increased as the level of seabass oil increased (P < 0.05). When MFI was incorporated into surimi gel, lower PV was obtained throughout the storage (P < 0.05). Addition of seabass oil pre-emulsified with soy protein isolate (SPI) in the presence of MFI yielded surimi gel with the highest breaking force and could improve oxidative stability during refrigerated storage (P < 0.05). Slight decrease in whiteness was found in surimi gel added with MFI, while those added with MFI along with pre-emulsified seabass oil showed increased whiteness (P < 0.05). Addition of MFI did not affect total viable count and psychrophilic bacterial count in surimi gels. Thus, the incorporation of pre-emulsified seabass oil prepared using SPI in conjunction with MFI could improve quality and oxidative stability of gel from bigeye snapper surimi.  相似文献   

13.
Fisheries-independent survey data are vital to stock assessment and management because they provide reliable information on stock status. Although survey data have been increasingly recognised for their contributions to fisheries management, they have often not been adequately used to provide quantitative management recommendations for China's fisheries that are subject to limited data. In the present study, a framework was proposed to integrate two types of survey-based management procedures (MPs) into China's fisheries management: the slope-based MP and the target-based MP. Specifically, the former generates fishing effort limits based on the trend in recent years’ abundance index, while the latter sets effort limits based on a static abundance index target. To test the performance of these MPs, management strategy evaluation was performed using a simulated fishery based on the small yellow croaker, Larimichthys polyactis (Bleeker) in Haizhou Bay, China. The sensitivity of MPs was investigated under different algorithm parameterisations and historical exploitation levels. Additionally, their robustness was evaluated in the face of survey uncertainty and changes in recruitment success. Both MPs could effectively improve the stock status compared with the status quo management when appropriately parameterised regardless of exploitation history. The target-based MP was more robust to survey uncertainty than the slope-based MP. Non-stationary changes in recruitment success strongly impaired the management effects, while using recruitment-specific instead of the age-aggregated abundance index could slightly enhance their performance. This work indicates that survey-based MPs can address the current challenges in China's fisheries management and reinforce the status quo management practice with limited data and highlights the potential risks.  相似文献   

14.
Abstract

Copper sulfate is an algicide that is commonly used for phytoplankton and filamentous algae control and has been used as a therapeutant in aquaculture. The objectives of this study were to determine the acute toxicity of copper sulfate and the safe level for use in freshwater prawn, Macrobrachium rosenbergii, production ponds in a high calcium and alkalinity environment. Six concentrations of copper sulfate (0, 0.2, 0.4, 0.6, 0.8, 1.0 mg/L) were tested in 8-L glass aquaria for 48 hours with three replicate aquaria per treatment. Concentrations of calcium hardness and alkalinity were set at 100 mg/L using calcium chloride and sodium bicarbonate, respectively. After 48 hours, survival of the control treatment (0% CuSO4) averaged 97%, which was significantly higher (P< 0.05) than that of all other treatments. The survival in the 0.2 mg/L and 0.4 mg/L (70% and 73%, respectively) concentrations of CuSO4 were significantly greater (P< 0.05) than higher dose treatments; but were not significantly different from each other (P> 0.05). Treatments containing 0.6, 0.8, and 1.0-mg/L copper sulfate demonstrated a dramatic decrease in prawn survival, which averaged 30, 7, and 0%, respectively. Regression analysis of the data predicted 48-hour LC50 for copper sulfate tobe0.46 mg/L. Since recommended application rates for use of copper sulfate as an algicide are 1.0 mg/L or more for water with alkalinities of 100 mg/L, copper sulfate treatments are not recommended for prawn production ponds.  相似文献   

15.
ABSTRACT

Little is known regarding the correlation between channel catfish female body weight and relative fecundity and fry production when the females are induced to ovulate with carp pituitary extract and fertilized with blue catfish sperm. A total of 145 female channel catfish were used in the early, middle, and late spawning season. Female body weight of channel catfish had negative correlations with relative fecundity (r = ?0.33 and ?0.25, P < .05; r = ?0.23, P > .05) and before the late spawning season with fry/kg (r = ?0.21, P > .05; r = ?0.30, P < .05). Eggs/kg female body weight and fry/kg female body weight followed a parallel pattern throughout the season, illustrating the logical relationship between relative fecundity and fry output. The size of females used is a consideration to maximize hybrid catfish embryo production during the early and middle spawning season but not late in the spawning season. However, these correlations are relatively small even though significant; thus a dramatic change in fry production would not be predicted. Since reproductive relationships can change during the spawning season, conclusions and recommendations could be flawed if data are not collected periodically during an entire spawning season.  相似文献   

16.
The aim of this study was to investigate the impact of two types of fish raw material on fishmeal (FM) physicochemical properties, specific mechanical energy, starch gelatinization and physical feed quality. Eleven feed mixes based on six independent FMs from herring (FMH) and five from sand eel (FMSE) were extruded according to standardized conditions. Type of fish raw material influenced FM physicochemical properties and had significant impact on starch gelatinization and pellet hardness. Multivariate models were established based on partial least squares regression (R2 = 0.637–0.999). Improved degree of starch gelatinization was associated with increased degree of protein hydrolysis (P = 0.011) and by replacement of FMH with FMSE in the feed mix (P = 0.012). A large span in pellet hardness was observed (4.9–94.1 N). Improved hardness was associated with decreased level of non‐soluble protein (P < 0.001) and by replacement of FMSE with FMH (P < 0.001). For FMSE, improved hardness was associated with decreased level of non‐soluble protein (P < 0.001) and increased degree of protein hydrolysis (P = 0.002), compressed bulk density (P = 0.039) and dust fraction (P = 0.001). The underlying physical and chemical mechanisms are discussed. The study documents differences in technical quality of FM produced from herring and sand eel with significant impact on fish feed extrusion and pellet quality.  相似文献   

17.
ABSTRACT

The objective of the current study was to determine the effects of chitosan (CH) coatings containing Mentha spicata essential oil (MSO; 0.2 and 0.4%) and zinc oxide nanoparticle (ZnO; 0.2 and 0.4%) on chemical (total volatile basic nitrogen (TVB-N), 2-thiobarbituric acid reactive substances (TBARS) and peroxide value (PV)), microbial (total viable count, psychrotrophic count, Pseudomonas spp., and Enterobacteriaceae) and sensory (odor, color, and overall acceptability) properties of raw rainbow trout fillets during 14 days of refrigerated storage. Final microbial population of CH + MSO 0.4% + ZnO 0.4% and CH + MSO 0.4% + ZnO 0.2% retarded approximately 3–5 log CFU/g as compared to control groups (P < 0.05). At the end of storage time in control samples, TVB-N, TBARS, and PV reached 49.3 mg N/100 g, 3.31 mg malonaldehyde/kg, and 2.04 meq peroxide/kg lipid, while the values for the treated samples with MSO (0.2 and 0.4%) in combination with ZnO (0.2 and 0.4%) remained lower than 25 mg N/100 g, 2 mg malonaldehyde/kg, and 1.1 meq peroxide/kg lipid, respectively. The results indicate a potential use of CH coating containing MSO and ZnO as an effective type of antimicrobial packaging to maintain quality of rainbow trout fillets.  相似文献   

18.
研究微塑料（microplastics,MPs）对稻田土壤―水界面中重金属空间分布特征和迁移规律的影响机制,可为微界面环境中MPs和重金属交互作用及生态风险评估提供理论支撑和科学依据。2021年7月对采自东北地区稻田的土壤添加不同浓度不同粒径的MPs,借助薄膜梯度扩散技术（DGT）在毫米尺度上获取稻田土壤―水微界面生物有效态重金属元素的原位高分辨信息,并根据Fick第一扩散定律评估不同MPs添加处理下重金属元素的迁移特征和释放通量。结果表明：（1）稻田土壤―水微界面生物有效态Mn、Co、Fe、Ni、Zn、Pb、Cu和Cd浓度在剖面上具有显著的空间分布差异;（2）MPs的添加显著降低了有效态Cu（-50.7%~8%,P<0.001）、Zn（-17.1%~-4.1%,P<0.001）和Cd（-16.7%~-2.2%,P<0.001）的浓度;（3）土壤MPs添加改变了有效态Cu的迁移方向,使土壤由Cu源转化成Cu汇,说明MPs对Cu存在明显的吸附效应;（4）不同粒径MPs的添加对生物有效态Ni的影响差异较大,大粒径（80 μm）MPs增加了其浓度,小粒径（10 μm）则相反。  相似文献   

19.
The use of active biodegradable films from renewable sources like anchovy, with the incorporation of organic acids, such as sorbic acid (SA) and benzoic acid (BA), is an alternative to decrease environmental pollution and minimize the development of fungi in foods. This study investigated the respective influences of SA and BA at 0, 0.50, 0.75, and 1.50% on the growth of Aspergillus flavus and Rhizopus oryzae and on Argentine anchovy protein film properties (L*, a*, b*, tensile strength, elongation at break, solubility in water, water vapor permeability, and Fourier transform infrared spectroscopy (FTIR)). Results showed that the incorporation of SA or BA at different levels significantly increased the water vapor permeability, water solubility, and elongation at break of the films, but decreased the tensile strength and L* parameter (p < 0.05). FTIR evidenced an interaction between the BA and Argentine protein isolate. Also, the influences of the SA or BA concentration on antifungal activity was observed. The greatest effectiveness was obtained for films containing SA against R. oryzae compared to BA film treatments. In conclusion, the Argentine anchovy protein films could retain their antifungal property by incorporation of these organic acids.  相似文献   

20.
ABSTRACT

The viscoelastic properties of gelatin extracted from tilapia skin (protein yield: 21.2%) were evaluated using dynamic rheology tests. The flow curves of tilapia gelatin sols (1.0–6.6% w/w, 40°C; 0.5%, 2–40°C) complied with the Herschel-Bulkley model (R2 = 0.92–0.99), indicating the presence of yield stress, while the gelling and melting temperature of gelatin dispersions (1.0–6.6%) fit well with the Eldridge-Ferry model (R2 = 0.97). Tilapia skin gelatin displayed good thermo-stability and strong gel-forming properties, showing great potential as an alternative for mammal-based gelatin applied in various food products.  相似文献   

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