The objective of this work was to produce protein hydrolysates from by-products of the Nile tilapia fileting process, and to assess the effects of different hydrolysis times on the antioxidant activity of the hydrolysed animal-based protein, in free form and incorporated into a food matrix. Gutted tilapia heads and carcasses were hydrolysed by Alcalase  for different hydrolysis times producing six hydrolysates. The protein content, degree of hydrolysis, reverse-phase high-performance liquid chromatography, and antioxidant activity by the ORAC, FRAP and TEAC methods were analysed. Three mini-hamburger formulations were produced and the lipidic oxidation of mini-hamburger was determined by TBARS. The protein contained in the residue was completely recovered in the process. The hydrolysates varied in their degree of hydrolysis, but presented similar levels of antioxidant activity. In the mini-hamburgers the hydrolysate was capable of delaying oxidation after 7 days of storage. Hydrolysis of tilapia processing by-products produced peptides may be used in the formulation of functional foods.Keywords: fish; protein; hydrolysis; antioxidants.Practical Application: The practical application of this work is the production of peptides with antioxidant activity using protein recovery from a raw material considered a residue or by-product of Nile Tilapia processing.

ABSTRACT. This study aimed to evaluate the digestibility of tilapia by-product protein hydrolysate powder (TBHP) from tilapia filleting by-product, and its inclusion in diets for Nile tilapia larvae. In order to determine the apparent digestibility coefficients, two diets were formulated, the reference diet and the test diet (20% of TBHP) and, to evaluate the inclusion, six diets were formulated, which were with 0.0, 2.0; 4.0; 6.0, and 8.0% of TBHP. The apparent digestibility coefficients of crude protein and gross energy were 89.5 and 98.3%, respectively. At levels above 4.0% of inclusion of TBHP, the weight, final length and weight gain were impaired, however, survival rate was higher (p < 0.05). The TBHP can be used in diets for tilapia due to the high digestibility coefficients for crude protein and gross energy. The inclusion of up to 4.0% of TBHP does not affect the reproductive performance and survival rate of Nile tilapia larvae.Keywords: digestibility, fish nutrition, performance.Hidrolisado proteico seco do resíduo da filetagem de tilápias em dietas para larvas de tilápia do Nilo RESUMO. Objetivou-se avaliar a digestibilidade do hidrolisado proteico seco do resíduo da filetagem de tilápias (HPST) e sua inclusão em dietas para larvas de tilápia do Nilo. Para determinar os coeficientes de digestibilidade aparente, duas dietas foram elaboradas, referência e teste (com 20% do HPST) e para avaliação da inclusão, seis dietas foram formuladas com 0,0, 2,0; 4,0; 6,0, e 8,0% de HPST. Os coeficientes de digestibilidade aparente da proteína e energia bruta foram de 89,5 e 98,3%, respectivamente. Nos níveis acima de 4,0% de inclusão de HPST o peso e comprimento final e ganho em peso foram prejudicados, no entanto a sobrevivência foi maior (p < 0,05). O HPST pode ser utilizado em dietas para tilápias em função dos elevados coeficientes de digestibilidade para proteína bruta e energia bruta. A inclusão de até 4,0% de HPST não afeta o desempenho produtivo e a sobrevivência de larvas de tilápias do Nilo.Palavras-chave: digestibilidade, nutrição de peixes, desempenho.

The influence of alcohol:oil molar ratio on the canola oil transesterification reaction in solvent-free medium using free lipase from Thermomyces lanuginosus and Burkholderia cepacia was studied. The experiments conducted in batch reactor for 72 h at 37°C in cosolvent-free reaction system with ethanol addition in three steps showed great potential for ester production. The stepwise addition of ethanol allowed increasing yield throughout the total period of the reaction, even if the course has limited reaction at times, minimizing possible deleterious effects of the alcohol on the enzyme structure. The highest yields were achieved with lipase from T. lanuginosus, despite presenting lower activity values than those of Burkholderia cepacia lipase, which proved to be less selective for ester production. In the reaction medium containing lipase from T. lanuginosus, 100 % yield was obtained using a molar ratio of 12:1. For B. cepacia lipase, the highest yield was 90.73% at a molar ratio of 6:1. In all cases studied, at least 92% of the triacylglycerols from canola oil were consumed.

Resumo AbstractO farelo de soja é um dos principais resíduos da agroindústria brasileira, tendo em vista a grande produção nacional do grão. has shown superior results of productivity, specially in the cultivation of filamentous fungi and the production of enzymes. The present study aimed the production of the enzymes protease, amylase and invertase by SSF using conventional soybean meal and the fungus A. casiellus.The pH and nutrient sources were evaluated and, finally, an optimization of the parameters of the SSF through experimental design and construction of growth curves of the fungus were carried out. The optimization of the invertase production process reached the best values for specific enzymatic activity (AEesp) at neutral pH (6.7)

ABSTRACT. In the last few decades, the offer of by-products obtained from the processing of tilapia (Oreochromis niloticus) has increased, and the need for developing products with high biological and nutritional values for use in animal nutrition motivated this study. Enzymatic hydrolysis of carcass, head and skin of tilapia was performed, as well as the separation of oil, residual solids and soluble proteins by centrifugation at high temperature and the spray drying of the protein fraction. Factorial designs were employed in the assays to evaluate the operating conditions of the spray dryer (inlet and outlet temperatures and flow rate) and the inclusion of drying aid agents (maltodextrin and calcium carbonate). The spray drying showed the best results with air inlet temperature of 190ºC, outlet temperature of 90ºC, flow rate of 30 L·h -1 including 10% maltodextrin (mass) in the liquid feed as a drying aid. The final powder recovery was higher than 90% and the physical, chemical and microbiological analyses met the Brazilian legal standards.

RESUMO.A soja possui ampla disponibilidade de componentes bioquímicos como proteínas, polissacarídeos, lipídios, carboidratos, minerais, vitaminas, fibras, lecitina, dentre outros, tornando interessante sua utilização como substrato para a fermentação em estado sólido (FES). Este processo, apesar de não ser tão utilizado industrialmente quanto à fermentação submersa (Fsm), apresenta-se viável, pois tem apresentado resultados superiores de produtividade, principalmente no cultivo de fungos filamentosos e na produção de enzimas. Assim, o objetivo deste trabalho foi o de comparar a produção de diferentes tipos de complexos enzimáticos por FES utilizando diferentes tipos de sojas (orgânica, transgênica e convencional) com o fungo Aspergillus niger. Realizou-se a caracterização dos substratos para a produção de amilase, protease e lipase, avaliação das curvas de crescimento do microrganismo e das condições ótimas de produção da protease utilizando planejamento de experimentos. As maiores atividades enzimáticas no estudo dos parâmetros da fermentação foram observadas para a protease, utilizando soja convencional com umidade inicial de 50%, 144h de fermentação, concentração inicial do inóculo de 4.10 6 esporos g -1 e tamanho de partícula de 0,6 mm. O estudo de otimização do processo indicou que os melhores resultados de atividade enzimática para a protease foram obtidos em pH 3,0 e tamanho de partícula dos grãos de soja de 0,6 mm após a fragmentação para as fermentações.Palavras-chave: fermentação sólida, planejamento de experimentos, complexos enzimáticos.Enzyme complexes production by A. niger from soybean under solid state fermentation ABSTRACT. Soybean has a wide availability of biochemical compounds as proteins, polysaccharides, lipids, carbohydrates, minerals, vitamins, fibers, lecithin, among others, making interesting its employment as substrate for solid state fermentation. Although the process of SSF is not extensively used industrially like the submerged fermentation (SmF), it can be a viable alternative, since presents higher results of productivity, especially at the cultivation of filamentous fungi and enzymes production. In this way, this study compared the production of different types of enzymes through solid-state fermentation, using different types of soybean cultures (organic, transgenic and conventional) with the fungus A. niger. We accomplished the characterization of the substrates for the production of amylase, protease and lipase, evaluation of the growth curves of the microorganism and the optimal conditions of enzymes production using experimental design. The highest enzyme activities in the study of fermentation parameters were observed for the protease, using conventional soybeans with initial moisture of 50%, 144h of fermentation, initial inoculum concentration of 4.10 6 spores g -1 and particle size of 0.6 mm. The study of process optimization indicated that the best results of enzyme activity for the protease were obtained at pH 3.0 and particle size of soybean fragmentation of 0.6 mm.

The use of lipases in industrial processes can result in products with high levels of purity and at the same time reduce pollutant generation and improve both selectivity and yields. In this work, lipase from Thermomyces lanuginosus was immobilized using two different techniques. The first involves the hydrolysis/polycondensation of a silica precursor (tetramethoxysilane (TMOS)) at neutral pH and ambient temperature, and the second one uses tetraethoxysilane (TEOS) as the silica precursor, involving the hydrolysis and polycondensation of the alkoxide in appropriate solvents. After immobilization, the enzymatic preparations were dried using the aerogel and xerogel techniques and then characterized in terms of their hydrolytic activities using a titrimetric method with olive oil and by the formation of 2-phenylethyl acetate in a transesterification reaction. The morphological properties of the materials were characterized using scanning electron microscopy, measurements of the surface area and pore size and volume, thermogravimetric analysis, and exploratory differential calorimetry. The results of the work indicate that the use of different silica precursors (TEOS or TMOS) and different drying techniques (aerogel or xerogel) can significantly affect the properties of the resulting biocatalyst. Drying with supercritical CO2 provided higher enzymatic activities and pore sizes and was therefore preferable to drying, using the xerogel technique. Thermogravimetric analysis and differential scanning calorimetry analyses revealed differences in behavior between the two biocatalyst preparations due to the compounds present.

Context The inclusion of natural products with antioxidant properties in animal diets as well as the use of different lipid sources has been tested to improve the nutritional quality of meat. Aim The aim of this work was to compare natural products with antioxidant properties and vitamin E in swine diets containing flaxseed oil. Methods Ninety-six animals were allocated to six treatments: control diet (C), diet with 3% flaxseed oil (F), diet with 3% flaxseed oil + 10% grape pomace (FGP), diet with 3% flaxseed oil + 0.0022% grape seed extract (FGE), diet with 3% flaxseed oil + 5% Nile tilapia carcass hydrolysate (FH), and diet with 3% flaxseed oil + 200 ppm vitamin E supplement (FVitE). Key results The treatments had no effect on growth performance or serum total antioxidant status, while low-magnitude effects on carcass traits were observed. The addition of flaxseed oil to the diet increased the omega-3 and total polyunsaturated fatty acid concentrations and decreased saturated fatty acid and monounsaturated fatty acid concentrations in meat; high concentrations of total tocopherol were observed in the treatments FVitE, FGE, and FH, while a higher oxidative stability (Rancimat®) of backfat was observed for the treatment FVitE. The thiobarbituric acid-reactive substances assay and the sensory evaluation of mini-burgers revealed that vitamin E was the most efficient antioxidant throughout the storage, although the treatments FH and FGE have presented a mild effect. Conclusions Problems of oxidative stability of pork resulting from including flaxseed oil in the diet of pigs due to increases in omega-3 fatty acids were better overcome by dietary vitamin E than by the use of the other natural antioxidants assessed here. However, this study also demonstrated that both the tilapia hydrolysate and grape seed extract have potential to be used as natural antioxidants, although further studies are required. Implications The results impact the meat industry in regard to the nutritional quality and oxidative stability of meat. Pork with higher omega-3 content and natural antioxidants can meet consumer demand for a healthier diet, besides providing higher stability throughout storage, providing an additional market niche for the pork industry.