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.

Characteristic and shelf life of fish sausage: fortification with fish oil through emulsion and gelled emulsion incorporated with green tea extract.

BACKGROUND: Silver carp (Hypophthalmichthys moltrix) fish sausages incorporated with three forms of refined cod liver oil (as a source of polyunsaturated fatty acids: fish oil, oil-in-water emulsion (E), gelled oil-in-water emulsion (G)) and lyophilized aqueous extract of green tea (Camellia sinensis; 700 and 900 mg kg-1 ) were developed. The composition, technological properties (cooking loss, pH, texture, and color), sensory analysis, and microbial and oxidative stability of fish sausages during storage (4 °C) were evaluated. RESULTS: Lower value of cooking loss and thiobarbituric acid value were observed by addition of fish oil in emulsions forms. The incorporation of green tea showed no significant differences in preventing oxidation in related samples. Gelled-emulsified fish oil had better textural properties, including hardness and decreased springiness of the sausages. The G and E sausages showed higher values of lightness (L* ) than the control did. Emulsification had no significant effect on total viable count. Panelists could not distinguish between samples incorporated with fish oil whether in emulsified, gelled-emulsified, or control. Gelled-emulsified treatments were awarded higher scores by panelists for all of the sensory attributes (P < 0.05). Eicosapentaenoic acid and docosahexaenoic acid quantities significantly increased from control (0.48 mg g-1 and 0.46 mg g-1 sample respectively) to the enriched batches (>1.50 mg g-1 sample). The lowest ratio of ω6 to ω3 in batches was observed for gelled-emulsified samples. CONCLUSION: Overall, the addition of free fish oil affected the properties of the sausages. The gelled-emulsified treatment was a suitable fish oil delivery system in fish sausages, which maintained sensory properties during refrigerated storage.

Levan Exerts Health Benefit Effect through Alteration in Bifidobacteria Population

BAckground: Recently, exploring novel dietary nondigestible carbohydrates, which are able to influence the gut flora, has drawn much attention. The objective of this study was to find out the effective dose of levan, as a prebiotic, in rats in order to further apply in food industry. Methods: Levan at various doses (2-10%) was orally administered to male Wistar Albino rats once a day for 90 days. At the end of experiment, fecal and blood samples were collected to measure gut bacteria population and to carry out serum biochemical assay. The rats were sacrificed, and the colon tissues were stained with hematoxylin and eosin and analyzed by histopathology. Results: Of note, levan effectively controlled body weight gain in the rats. Serum biochemical analysis revealed that 5% levan significantly diminished the serum level of total cholesterol, LDL, and glucose as well. More notably, 5% levan intake significantly increased the abundance of bifidobacteria population, highlighting its bifidogenic effect. Furthermore, our histopathological result revealed that daily intake of levan was associated with a higher degree of thickness of the mucosa layer compared to the rats in control group. Moreover, these findings manifested no colon inflammation in the rats fed with levan. Conclusion: The findings of this study provide the fundamental data to use levan at a definite dose for further development in functional foods.

Addition of seaweed powder and sulphated polysaccharide on shelf_life extension of functional fish surimi restructured product.

This study aimed to investigate the performance of equal amounts of edible green seaweed, Ulva intestinalis powder (2.77 g kg-1), and its sulphated polysaccharide ([USP], 0.5 g kg-1, based on the extraction yield from U. intestinalis powder) on the proximate compositions, lipid oxidation, pH, colour, textural properties, cooking yield and sensory attributes of fish-surimi restructured products during storage at - 18 °C as compared with the control. Results showed incorporation of two functional components resulted in lower TBARS values compared with the control over 6 months (P ≤ 0.05). The USP incorporated fingers showed the least moisture loss over 6 months (P < 0.05). Textural properties for two functional fingers remained relatively stable from month 0 to month 6, while the hardness increased significantly (P < 0.05) in the control fingers (67 to 80 N). Additionally, the sensory attributes of all formulated fingers were judged acceptable; however, the USP containing fingers were preferred by the sensory panelists, due to their juicy texture as a result of less cooking loss comparing with others. In conclusion, this study suggests the potential use of such natural marine ingredients to maintain the quality and to extend the shelf life of surimi-based products with beneficial health effects.

Fractionation of Protein Hydrolysates of Fish Waste Using Membrane Ultrafiltration: Investigation of Antibacterial and Antioxidant Activities.

In this study, yellowfin tuna (Thunnus albacores) viscera were hydrolyzed with protamex to obtain hydrolysate that is separated by a membrane ultrafiltration into four molecular size fractions (< 3, 3-10, 10-30, and 30 kDa <). Antibacterial and antioxidant properties of the resulting hydrolysates and membrane fractions were characterized, and results showed that the lowermost molecular weight fraction (< 3 kDa) had significantly the highest (P < 0.05) percentage of bacteria inhibition against Gram-positive (Listeria and Staphylococcus) and Gram-negative (E. coli and Pseudomonas) pathogenic and fish spoilage-associated microorganisms and scavenging activity against DPPH and ABTS radical and ferric reducing antioxidant power among the fractionated enzymatic hydrolysates. These results suggest that the protein hydrolysate derived from yellowfin tuna by-products and its peptide fractions could be used as an antimicrobial and antioxidant ingredient in both nutraceutical applications and functional food.

Using WPC-inulin-fucoidan complexes for encapsulation of fish protein hydrolysate and fish oil in W1/O/W2 emulsion: Characterization and nutritional quality.

The double emulsions and freeze-dried microcapsules containing fish protein hydrolysate (FPH) and fish oil (FO) were stabilized by complexs of whey protein concentrate (WPC) with inulin (Inu) and fucoidan (Fuc) in terms of physical characteristics (particle size distribution, morphology, encapsulation efficiency, solubility, …), oxidative stability, nutritional quality and in vitro release. Higher encapsulation efficiency and solubility were observed in Fuc-WPC microcapsules (86.31% and 30.26 mg/100 g, respectively). The combination of Fuc-WPC in the wall material showed higher oxidative stability than other wall material. The higher values of PUFA and SFA were observed in Inu-WPC Fuc-WPC microcapsules, respectively. The Fuc-WPC and Inu + Fuc-WPC micrographs showed a more porous structure compared to Inu-WPC. The mean particle size ranged from 536.8 ±â€¯52.70 to 842.36 ±â€¯21.41 nm. No significant differences were observed in the released oil and the fatty acid composition during gastrointestinal digestion. Sensory evaluation of fortified natural yogurt with microcapsules showed lower fishy flavor in Inu-WPC samples than those fortified with Fuc-WPC and Inu + Fuc-WPC. In general, the use of inulin with WPC as a wall materal resulted in good characteristics and sensory attributed, although the use of fucoidan with WPC conferred higher oxidative stability during storage.

Bacterial cellulose nanofibers as reinforce in edible fish myofibrillar protein nanocomposite films.

Bacterial cellulose nanofibers (BCNF) were employed in order to improve various properties of fish myofibrillar protein (FMP) films of Silver carp. Three different levels (2, 4 and 6%, w/w) of the nanoparticles were added to the protein polymer substrate. In this regard, it became clear that 6% BCNF-containing nanocomposites had the highest tensile strength, which was about 49% better than control samples. The nanoparticles had positive impact on the physical properties; BCNF-containing films showed a reduction in water vapor permeability, swelling and solubility indexes. The results of SEM displayed uniform distribution and continuous cross-section of nanocomposite films. FTIR analysis of different films showed molecular interactions between nanoparticles and polymer substrate. XRD analysis represents the appearance of new peaks in polymer nanocomposites and the increase in crystallization of these films compared to the control film. Evaluation of thermal properties of these films suggests the improved thermal stability of the nanocomposites.

Extraction of unsaturated fatty acid-rich oil from common carp (Cyprinus carpio) roe and production of defatted roe hydrolysates with functional, antioxidant, and antibacterial properties.

BACKGROUND: Common carp roe is a rich protein and oil source, which is usually discarded with no specific use. The aims of this study were to extract oil from the discarded roe and examine functional, antioxidant, and antibacterial properties of defatted roe hydrolysates (CDRHs) at various degrees of hydrolysis (DH). RESULTS: Gas chromatography of fatty acid methyl esters revealed that common carp roe oil contained high levels of unsaturated fatty acids. The results of high-performance liquid chromatography-mass spectrometry indicated that enzymatic hydrolysis of defatted roe yielded higher content of essential amino acids. CDRHs displayed higher solubility than untreated defatted roe, which increased with DH. Better emulsifying and foaming properties were observed at lower DH and non-isoelectric points. Furthermore, water and oil binding capacity decreased with DH. CDRHs exhibited antioxidant activity both in vitro and in 5% roe oil-in-water emulsions and inhibited the growth of certain bacterial strains. CONCLUSION: Common carp roe could be a promising source of unsaturated fatty acids and functional bioactive agents. Unsaturated fatty acid-rich oil extracted from common carp roe can be delivered into food systems by roe oil-in-water emulsions fortified by functional, antioxidant, and antibacterial hydrolysates from the defatted roe. © 2017 Society of Chemical Industry.

Evaluation of some qualitative variations in frozen fillets of beluga (Huso huso) fed by different carbohydrate to lipid ratios.

In this study, juvenile beluga (Huso huso) was fed by the diets containing different carbohydrate to lipid ratios for 5 months. At the end of culture period, proximate compositions of the fish carcasses (moisture, protein, lipid, and ash) were measured. Then, qualitative changes in the fishes were evaluated during 6 months frozen storage (-20 °C) along with recording changes in their Total Volatile Bases Nitrogen (TVN), Thiobarbituric Acid (TBA), Free Fatty Acids (FFA), pH, and muscle texture profile analysis. The results of proximate analysis of the carcasses showed that moisture, protein, and ash of the carcasses increased significantly (p < 0.05) with higher carbohydrate to lipid ratio, but lipid content of the carcasses decreased significantly (p < 0.05). Also, during frozen storage, TVN, TBA, and FFA increased significantly in all the samples (p < 0.05). Significant differences were detected in pH of the treatments (p < 0.05), but these changes didn't follow a regular pattern in all the treatments. The results of muscle texture profile analysis showed lower chewiness, hardness, and gumminess during the first 3 months of frozen storage; however, after 6 month, the values increased significantly compared to those in 3 months. Different characteristics of texture showed significant differences in the treatments during frozen storage (p < 0.05), although these changes didn't follow an identical pattern in all the treatments. It can be concluded that carbohydrate higher than 27% in diet has had adverse effect on quality of fillets during frozen storage. However, lipid levels used in the present study haven't had significant influence on quality of the fillets during the preservation.

Comparison of chitosan-gelatin composite and bilayer coating and film effect on the quality of refrigerated rainbow trout.

The effect of chitosan-gelatin coating and film on the rancidity development in rainbow trout (Oncorhynchus mykiss) fillets during refrigerated storage (4±1 °C) was examined over a period of 16 days. Composite and bilayer coated and film wrapped fish samples were analysed periodically for microbiological (total viable count, psychrotrophic count) and chemical (TVB-N, POV, TBARS, FFA) characteristics. The results indicated that chitosan-gelatin coating and film retained their good quality characteristics and extend the shelf life of fish samples during refrigerated storage .The coating was better than the film in reducing lipid oxidation of fillets, but there was no significant difference between them in control of bacterial contamination.

Effect of dietary nutrient density and vitamin premix withdrawal on performance and meat quality of broiler chickens.

BACKGROUND: The objective of this study was to evaluate the effects of feeding high- and low nutrient density diets, and three different vitamin premix withdrawal regimes on broiler performance and meat quality. Male broiler chicks (480 days old) were reared on the floor in a 2 × 3 factorial arrangement for 42 days. Chickens were slaughtered at 42 days of age and meat samples kept at -20 ± 1°C and analysed after 1, 90 and 180 days of storage. RESULTS: Broiler performance was significantly affected by dietary nutrient density. Vitamin premix withdrawal had no significant effect on body weight. The results showed no significant differences between nutrient density and vitamin premix withdrawal on lightness (L*), redness (a*) and yellowness (b*). Oxidative stability of thigh muscle lipids during frozen storage was significantly affected by nutrient density, while vitamin premix withdrawal had no significant impact on lipid oxidation. High nutrient density diet led to a significantly (P < 0.05) decreased pH compared with the low nutrient density diet. CONCLUSION: Increasing dietary nutrient density improved broiler performance but impaired meat quality while vitamin premix withdrawal during finisher periods had no negative effect on broiler performance and meat quality.

Sulfated polysaccharides purified from two species of padina improve collagen and epidermis formation in the rat.

Sulfated polysaccharides have shown promising effects on wound healing processes along with many other biological activities. The sulfated polysaccharides extracted from two algae species habitats in Persian Gulf were studied in vivo for their effects on collagen formation and epidermal regeneration. The polysaccharides were purified from aqueous extracts of P. tetrastromatica and P. boergesenii using CaCl2 and ethanol precipitation. The sulfate content of each polysaccharide was determined. Two identical wounds (either burn or excision) were made on the back of 4 groups of male Wistar rats (10 rats per group) under anesthesia. The algal polysaccharide ointments (2%) were applied twice daily on one side and the other wound was treated with Eucerin (as control). The rats were sacrificed on day 7 or 14, and then the wound samples were examined for epidermal thickness by light microscope. Furthermore, hydroxyproline content (as a marker of collagen formation) was spectro-photometrically measured. The polysaccharides purified from P. boergesenii had higher sulfate content (32.6±1%) compared to P. tetrastromatica (19±1%). Both algal polysaccharides showed some improvements in collagen formation (hydroxyproline content) and epidermal thickness in both wound models compared to the vehicle. The sulfated polysaccharides purified from P. tetrastromatica and P. boergesenii seaweeds are able to induce collagen formation and epidermal regeneration in the two wound models. The superior healing properties of P. boergesenii polysaccharides might be correlated to its higher sulfate content. Both algal polysaccharides are good candidates for wound healing clinical trials.