Browsing by Author "Fernández Giménez, Analía Verónica"

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    A new approach to fishery waste revalorization to enhance Nile tilapia (Oreochromis niloticus) digestion process.
    (2017-06-01) Rodriguez, Yamila Eliana; Pereira, Nair; Harán, Nora Selma; Mallo, Juan Carlos; Fernández Giménez, Analía Verónica
    The main goal of this research was to analyse in vitro compatibility of Nile tilapia (Oreochromis niloticus) digestive proteinases and enzymes recovered from species comprising fishery waste as Pleoticus muelleri, Artemesia longinaris and Patagonotothen ramsayi. It evaluated the use of exogenous enzymes as feed supplements to increase digestion efficiency in tilapia fingerlings and juveniles (3.5 ± 0.11 g and 11.6 ± 1.5 g, respectively). We successfully have obtained proteinases from fishery waste as source of exogenous enzymes. P. muelleri and A. longinaris enzymes had more activity of acid and alkaline proteinases than P. ramsayi. SDS-PAGE gels demonstrated that Nile tilapia digestive proteinases keep their activity when combined with each exogenous proteinase. Exogenous enzymes varied in their ability to enhance hydrolysis of different feed ingredients. P. muelleri by-products are the best candidates to be employed as feed supplements for tilapia juveniles. Enzymes from this by-product did not affect the activity and integrity of fish digestive enzymes, improved the hydrolysis of different protein sources (fish meal, squid meal, shrimp meal and soybean meal), and maintained its activity after being exposed to high temperatures and acid pHs. Our findings are applicable to other places where O. niloticus is raised utilizing local fishery waste, andalso to different cultured species.
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    Characterization of liquid protein hydrolysates shrimp industry waste: Analysis of antioxidant and microbiological activity, and shelf life of final product.
    (2021-04-19) Pereira, María de los Ángeles; Fangio, María Florencia; Rodriguez, Yamila Eliana; Harán, Nora Selma; Fernández Giménez, Analía Verónica; Bonadero, María Cecilia
    Abstract Proteases from shrimp wastes were characterized and protein hydrolysates were obtained. Shrimp protein hydrolysates (SPH) were produced by autolysis (H0) and added 1% (H1) and 2% vol/vol (H2) enzyme extract of shrimp. The hydrolysis degree was determined using a colorimetric method; the capability of hydrolysates to scavenge free radicals was measured with DPPH, and the antimicrobial activity of the SPH was evaluated by the microdilution test. The degree of protein hydrolysis ranged between 43% (H0) and 71.5% (H2) after 90 min, and it functioned as a source of lysine, leucine, aspartic acid, glutamic acid, and glycine. After 10 min of reaction, all hydrolysates reached 50% of scavenging effect. In addition, the SPH prepared with food additives showed acceptable microbiological quality and pH during 40 days at room temperature. This study aims at introducing a low-cost process which produces SPH with commercial applications in the food industry. Practical applications Currently, shrimp processing wastes represents an environmental and economic problem, since such seafood industry must pay for the landfarming service. This waste treatment is not environmentally efficient, and it affects the value of the final product. However, these wastes have a large number of compounds which hold biological activities of interest that can be used to obtain a high added value product such as protein hydrolysates. This by-product has several potential applications for the food and pharmaceutical industries. In this study, a protein hydrolysate solution was obtained utilizing processed shrimp waste as an enzymatic resource and a protein substrate as well. This research demonstrated the feasibility of obtaining a good protein source that also holds useful antioxidant properties. It is important to highlight that the by-product was obtained without resorting to freeze-drying technology, which makes the industrial process more expensive. To accomplish that, we included low-cost food preservatives and assessed the shelf life of this product of high nutritional quality.
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    Exogenous proteases from seafood processing waste as functional additives in rainbow trout aquaculture
    (2021-03-01) Rodriguez, Yamila Eliana; Pereira, Nair; Laitano, María V.; Moreno, Pablo; Fernández Giménez, Analía Verónica
    Previous studies about enzyme additives for salmonids employed commercial proteases from bacteria, but research obtaining such enzymes from other organisms are scarce. We aimed to increase digestive protease activity in Oncorhynchus mykiss, by analysing potential sources of exogenous proteases generated from different seafood processing waste. To date, there is no information regarding the influences that exogenous enzymes have on the activity and integrity of endogenous enzymes in salmonids. The compatibility and interaction between endogenous and exogenous proteases were evaluated through protein hydrolysis and electrophoresis. We also evaluated the capacity of two types of microcapsules (Alginate–Chitosan and Alginate–Chitosan– Bentonite) to protect the protease activity after being exposed to the gastric environment of trout. The seafood wastes had activities around 0.23–2.53 U/ml at 15°C. Among all the exogenous proteases evaluated, P. granulosa's extract showed the best performance, followed by L. santolla's extract. Such extracts increased the protein hydrolysis to equal or higher levels than the commercial protease and did not alter the integrity of trout proteases. The optimal catalytic function at low temperatures of these extracts might be linked to the habitat of these arthropods. Alginate–Chitosan– Bentonite microcapsules are recommended in preference to Alginate–Chitosan capsules for delivery of enzymes in salmonids because they ensure the activity of exogenous proteases for longer in acid pH (6 vs. 4 h). This research promotes a re-evaluation of seafood processing wastes through the production of a potentially functional additive that may improve trout protein digestion.