Search

A functional microemulsified concentrate was obtained from an industrial shrimp cooking effluent by using a centrifugal separator, resulting in a new effluent with only 5% of dry matter. The shrimp concentrate (C) showed valuable properties for use as a bioactive ingredient, being rich in lipids (~16%) and proteins (~11% w/w), and exhibiting antioxidant (radical scavenging capacity and reducing power) and antimicrobial properties. Chitosan–gelatin (ChG) biocomposites with and without the shrimp concentrate were prepared and characterized. The incorporation of C provided film-forming dispersions (S-ChGC) and dried films (F-ChGC) with increased antioxidant and antimicrobial activity. The film microstructure changed with the incorporation of the concentrate, which caused an evident plasticizing effect and reduced the tensile strength. The resulting biocomposites containing the shrimp cooking concentrate showed great potential for use in food applications (as food preservation or food design), medical devices or for cosmetic purposes, as wound dressing or film matrix for application on mucous membranes and epithelia with different functionalities.

Eight seafood protein hydrolysates (SPHs) obtained from squid, shrimp and fish gelatin were incorporated as substitutes of peptones in culture media in order to evaluate its effect on survival and metabolic activity (lactic acid, acetic acid and bacteriocins production) of Enterococcus faecalis DM19. The substitution of commercial peptones in culture media by either a shrimp hydrolysate prepared with Protamex, or by squid protein hydrolysates prepared with Esperase or Alkaline protease, stimulated E. faecalis DM19 growth up to 16%. The incorporation of SPHs, mainly from shrimp, in the culture media significantly increased production of lactic and acetic acids in more than 60%. Furthermore, the media containing SPHs stimulated antimicrobial activity by E. faecalis DM19. The inhibitory activity was observed against both Gram-positive and Gram-negative microorganisms, but it was remarkably observed against Listeria monocytogenes. SPHs incorporated in culture media render properties of bio-technological interest, which, together with their low price, make them suitable for industrial use.

An active shrimp concentrate (SC), obtained from Litopenaeus vannamei cooking juice, was incorporated into a chitosan-gelatin matrix to develop edible packaging covers (coating and film). Both types of packaging, which showed antimicrobial activity against some fish spoilers and pathogenic organisms, were applied to preserve fish sausages during chilled storage. The storage trial showed that the coating increased the lag phase of total viable microorganisms and enterobacteria to 15 and 10 days, respectively, while the film drastically inhibited growth of these groups. No presence of Staphylococcus aureus or lactic acid bacteria was detected in any batches during storage. Total volatile bases and pH values also decreased during storage, the decrease being more pronounced in the film. With regard to physical-chemical properties, the coated sausages exhibited values for moisture, water holding capacity, and shear strength similar to those of the control sausages until about day 25. The coating was imperceptible and could be a promising way of improving the quality of sausages during storage since it delayed microbial growth. The sausages wrapped in the film showed a drop in pH and moisture, as well as texture hardening, and were described as resembling a pickled product. The sausages were stable for at least 42 days, which represents a shelf life increase of at least this time with respect to the control sausages (in commercial plastic casings). The coating and the film had different effects on the physicochemical and microbiological properties of the fish sausage, and therefore on the stability of the product. In addition, the film triggered modifications in the product that resulted in a product different from the original, offering an attractive alternative with regard to product design.

© 2014 Elsevier Ltd. Chitosan prepared through a mild process using 10% NaOH during deacetylation and a protein concentrate (PCc) obtained from shrimp waste was used to develop active films. Film forming solutions were prepared by solubilizing chitosan with lactic acid without plasticizers addition. The structural properties of films, as observed by optical microscopy, Cryo-SEM, DSC and FTIR, were strongly affected by the addition of the PCc. Films with added PCc were much more tensile resistant but less deformable upon perforation. The presence of PCc also improved film barrier to the light. The films showed good antioxidant and antimicrobial properties, enhanced by the incorporation of PCc. The significance of these films lies in the fact that proteins do not usually appear to enhance antimicrobial properties, and therefore this is especially useful for food applications.

© 2015 Elsevier Ltd. An active coating solution composed of chitosan (Ch) and a shrimp protein-lipid concentrate (PCc), both obtained from Litopenaeus vannamei processing wastes, was applied to preserve shrimp during chilled storage. The addition of PCc increased the antioxidant capacity of the Ch coating, yielding a lower-viscosity mixture which, however, was viscous enough to adhere to the shrimp while maintaining its activity. The shrimp storage trial showed that the Ch coatings, especially when enriched with PCc (Ch-PCc), delayed microbial growth, mainly by extending the lag phase. Pseudomonas spp. appeared to be the predominant bacteria in the microbiota. H2S-producing organisms and luminescent colonies were especially sensitive to this active coating, with inhibition greater than 4 and 2 log cycle respectively, while the growth of lactic acid bacteria was not favored. The Ch-PCc coating delayed the onset of melanosis and did not confer any sensorially detectable color, taste or odor. It therefore shows promise as a means to improve the quality of shrimp during cold storage.

Active biodegradable bilayer films based on soy protein isolate, lignin and formaldehyde were developed. These films showed high water resistance and malleability, making them suitable for use in extreme environmental conditions. The presence of lignin in the formulation provided greater protection against light, especially UV. With the addition of 3%w/w citronella essential oil, the films showed good antifungal activity against Fusarium oxysporum pathogen microorganism in bananas. When the bananas were covered by the films during storage, there was a noticeable reduction in total aerobic mesophiles and moulds and yeasts. As the films aged (1, 3, 6 months), in both controlled and environmental conditions, the main active compounds in the citronella essential oil, citronellal and geraniol, were progressively released from the film matrix, citronellal more than geraniol. Over 30 days of soil degradation, the films lost around 30% of weight irrespective of the conditioning time. © 2014 Elsevier Ltd.

Several shrimp active materials, including protein concentrates, protein hydrolysates and a carotenoid extract, were recovered from shrimp ( Litopenaeus vannamei) processing residues (head and exoskeleton) and characterized in terms of chemical composition and antioxidative properties (Ferric ion reducing power and ABTS radical scavenging capacity). Different coating solutions were prepared by solubilizing chitosan, which was obtained from the residual chitinous material, in lactic acid and blending it with the various recovered materials. Chitosan-based solutions were tested for their viscosity and their antioxidative and antimicrobial properties against 26 selected microbial strains. All blend solutions showed higher antioxidant capacity and reduced viscosity as compared to the base chitosan solution. The incorporation of an astaxanthin-rich protein concentrate increased the antimicrobial capacity of the blend solution, but no further effect was observed after extra addition of the carotenoid extract. © 2013 Elsevier Ltd.