Binomial effects of high isostatic pressure and time on the microbiological, sensory characteristics and lipid composition stability of vacuum packed dry fermented sausages “chouriço”

The effect of high pressure processing (HPP), at different combinations of pressure and time, on dry fermented sausages (DFS)was evaluated by chemical, microbiological and sensory analyses. Lipid composition and stability were also assessed. HPP (N400MPa and longer than 154 s) produced a reduction in spoilage microbiota,without negative effect on fermentative microbiota, that will be able to continue their role. Total fatty acids and lipid stability were not affected. Only a small effect on fatty acid (FA) composition was observed. Nutritional value of the lipid fraction was only affected by the ratio n−6/n−3 FA. Treatments at 400MPa for 154 s or 960 s resulted in DFS being detected as different from control by sensory analysis. Those differences did not depreciate the product; on the contrary it seems to improve the bright aspect of the whole sausage, the cohesion and firmness and the correctly dried aspect of slices. Industrial relevance: Dry fermented meat sausages are very popular ready-to-eat meat based products. This study assesses the effects of HPP on this much appreciated traditional products. The results showed that HPP can be successfully applied to theseMediterranean fermented products without losses of sensory and nutritional characteristics. The modelling and optimization of the HPP process applied on dry fermented sausages demonstrated in this study are an advantage to industry efficiency. The utilisation of HPP by the industry can significantly increase dry fermented meat sausage shelf life and safety, providing it an opportunity to reach the global market

Procjena utjecaja visokoga tlaka na hidrolizu naringina u soku grejpfruta pomoću naringinaze imobilizirane u kapsulama kalcijeva alginata

The reduction of bitterness in citrus juices would increase their acceptance by the consumer. This reduction in grapefruit juices can be achieved as a result of an enzymatic process, with improved commercial value and maintenance of health properties. The use of a cheap, simple and effective immobilisation method combined with high pressure can be a key asset in the debittering of citrus juices. The aim of this study is the debittering of grapefruit juice under high pressure, with naringinase immobilized in calcium alginate beads. Naringinase, an α-rhamnopyranosidase, hydrolyzes naringin (a flavanone glycoside and primary bitter component in grapefruit juice) to naringenin, which is tasteless. High pressure can activate or inhibit enzymatic activities depending on the proteins and conditions. The hydrolysis of naringin was first evaluated in model solution (acetate buffer 0.02 M, pH=4.0) and then in grapefruit juice. In model solution, at 160 MPa and 37 °C, a 50 % increase in the concentration of reducing sugars was obtained when compared to the reaction at atmospheric pressure. The higher naringenin concentration (33 mg/L) was obtained at 54 °C under high pressure of 200 MPa, which corresponds to a naringin reduction of 72 % in model solution, while at atmospheric pressure (0.1 MPa), the naringin reduction was only 35 %. The decrease in naringin content can be directly correlated with the reduction in bitterness. From the concentration of residual naringin, the percentage of reduction in bitterness was evaluated. In grapefruit juice, a debittering of 75 % occurred with a pressure of 160 MPa at 37 °C for 20 minutes.Smanjenjem gorčine sokova citrusa povećala bi se njihova prihvatljivost za potrošače. Gorčina soka grejpfruta može se smanjiti enzimskim procesom koji poboljšava komercijalnu vrijednost soka, a ne smanjuje njegov pozitivan utjecaj na zdravlje. Uporaba jeftinih, jednostavnih i djelotvornih metoda imobilizacije, kombiniranih uz primjenu visokoga tlaka, ključni su za odgorčavanje sokova citrusa. Svrha je ovog istraživanja smanjiti gorčinu soka grejpfruta primjenom visokoga tlaka i naringinaze imobilizirane u kapsulama kalcijeva alginata. Naringinaza, tj. α-ramnopiranozidaza, hidrolizira naringin (flavanon glikozida što je osnovna gorka komponenta soka grejpfruta) u naringenin koji nema okus. Visoki tlak može aktivirati ili inhibirati aktivnost enzima ovisno o sastavu proteina i uvjetima hidrolize. U radu je najprije istražena hidroliza naringina u modelnoj otopini (acetatni pufer 0,02 M; pH=4,0), a zatim u soku grejpfruta. U modelnoj je otopini pri 160 MPa i 37 °C postignuto 50 %-tno povećanje koncentracije reducirajućih šećera, u usporedbi s reakcijom pri atmosferskom tlaku. Veća koncentracija naringenina (33 mg/L) postignuta je pri 54 °C i visokom tlaku od 200 MPa, što odgovara 72 %-tnoj redukciji narinigina u modelnoj otopini, dok je pri atmosferskom tlaku (0,1 MPa) redukcija naringina iznosila samo 35 %. Smanjenje koncentracije naringina može se povezati sa smanjenjem gorčine soka, tako da je postotak smanjenja procijenjen prema koncentraciji preostalog naringina. U soku grejpfruta smanjenje gorčine od 75 % postignuto je pri tlaku od 160 MPa, na 37 °C, tijekom 20 minuta

Procjena utjecaja visokoga tlaka na hidrolizu naringina u soku grejpfruta pomoću naringinaze imobilizirane u kapsulama kalcijeva alginata

The reduction of bitterness in citrus juices would increase their acceptance by the consumer. This reduction in grapefruit juices can be achieved as a result of an enzymatic process, with improved commercial value and maintenance of health properties. The use of a cheap, simple and effective immobilisation method combined with high pressure can be a key asset in the debittering of citrus juices. The aim of this study is the debittering of grapefruit juice under high pressure, with naringinase immobilized in calcium alginate beads. Naringinase, an α-rhamnopyranosidase, hydrolyzes naringin (a flavanone glycoside and primary bitter component in grapefruit juice) to naringenin, which is tasteless. High pressure can activate or inhibit enzymatic activities depending on the proteins and conditions. The hydrolysis of naringin was first evaluated in model solution (acetate buffer 0.02 M, pH=4.0) and then in grapefruit juice. In model solution, at 160 MPa and 37 °C, a 50 % increase in the concentration of reducing sugars was obtained when compared to the reaction at atmospheric pressure. The higher naringenin concentration (33 mg/L) was obtained at 54 °C under high pressure of 200 MPa, which corresponds to a naringin reduction of 72 % in model solution, while at atmospheric pressure (0.1 MPa), the naringin reduction was only 35 %. The decrease in naringin content can be directly correlated with the reduction in bitterness. From the concentration of residual naringin, the percentage of reduction in bitterness was evaluated. In grapefruit juice, a debittering of 75 % occurred with a pressure of 160 MPa at 37 °C for 20 minutes.Smanjenjem gorčine sokova citrusa povećala bi se njihova prihvatljivost za potrošače. Gorčina soka grejpfruta može se smanjiti enzimskim procesom koji poboljšava komercijalnu vrijednost soka, a ne smanjuje njegov pozitivan utjecaj na zdravlje. Uporaba jeftinih, jednostavnih i djelotvornih metoda imobilizacije, kombiniranih uz primjenu visokoga tlaka, ključni su za odgorčavanje sokova citrusa. Svrha je ovog istraživanja smanjiti gorčinu soka grejpfruta primjenom visokoga tlaka i naringinaze imobilizirane u kapsulama kalcijeva alginata. Naringinaza, tj. α-ramnopiranozidaza, hidrolizira naringin (flavanon glikozida što je osnovna gorka komponenta soka grejpfruta) u naringenin koji nema okus. Visoki tlak može aktivirati ili inhibirati aktivnost enzima ovisno o sastavu proteina i uvjetima hidrolize. U radu je najprije istražena hidroliza naringina u modelnoj otopini (acetatni pufer 0,02 M; pH=4,0), a zatim u soku grejpfruta. U modelnoj je otopini pri 160 MPa i 37 °C postignuto 50 %-tno povećanje koncentracije reducirajućih šećera, u usporedbi s reakcijom pri atmosferskom tlaku. Veća koncentracija naringenina (33 mg/L) postignuta je pri 54 °C i visokom tlaku od 200 MPa, što odgovara 72 %-tnoj redukciji narinigina u modelnoj otopini, dok je pri atmosferskom tlaku (0,1 MPa) redukcija naringina iznosila samo 35 %. Smanjenje koncentracije naringina može se povezati sa smanjenjem gorčine soka, tako da je postotak smanjenja procijenjen prema koncentraciji preostalog naringina. U soku grejpfruta smanjenje gorčine od 75 % postignuto je pri tlaku od 160 MPa, na 37 °C, tijekom 20 minuta

Quality Traits and Nutritional Value of Pork and Poultry Meat from Animals Fed with Seaweeds

ReviewSeaweeds have caught the attention of the scientific community in recent years. Their production can mitigate the negative impact of anthropogenic activity and their use in animal nutrition reduces the dependency on conventional crops such as maize and soybean meal. In the context of monogastric animals, novel approaches have made it possible to optimise their use in feed, namely polysaccharide extraction, biomass fermentation, enzymatic processing, and feed supplementation with carbohydrate-active enzymes (CAZymes). Their bioactive properties make them putative candidates as feed ingredients that enhance meat quality traits, such as lipid oxidation, shelf-life, and meat colour. Indeed, they are excellent sources of essential amino acids, polyunsaturated fatty acids, minerals, and pigments that can be transferred to the meat of monogastric animals. However, their nutritional composition is highly variable, depending on species, harvesting region, local pollution, and harvesting season, among other factors. In this review, we assess the current use and challenges of using seaweeds in pig and poultry diets, envisaging to improve meat quality and its nutritional valueinfo:eu-repo/semantics/publishedVersio

Impact of dietary Chlorella vulgaris and carbohydrate-active enzymes incorporation on plasma metabolites and liver lipid composition of broilers

ResearchBackground: Chlorella vulgaris has been proposed as a sustainable green feedstock in poultry nutrition due to its ease of cultivation, minimal environmental impact and balanced nutritional composition. However, the majority of studies documents the use of C. vulgaris as a dietary supplement in broilers instead of a feed ingredient. To the best of our knowledge, no report has shown the effect of a high-level incorporation (>2 % in the diet) of C. vulgaris on plasma metabolites and hepatic lipid composition of broilers. One hundred and twenty Ross 308 male birds were housed in 40 wired-floor cages and randomly distributed by the following experimental diets at 22 days of age (n = 10) during 15 days: (1) a corn-soybean meal based diet (control); (2) based diet with 10% of C. vulgaris; (3) diet 2 supplemented with 0.005% Rovabio® Excel AP; and (4) diet 2 supplemented with 0.01% of a pre-selected four-CAZyme mixture. Results: The inclusion of C. vulgaris at 10% in the diet, regardless of the presence of exogenous CAZymes, changed plasma metabolites but did not compromise broilers growth. Plasma total lipids increased in broilers fed C. vulgaris combined with the two feed CAZymes (p < 0.001) compared with the control diet. Moreover, the supplementation with Rovabio® increased total cholesterol and LDL-cholesterol, while the addition of the four-CAZyme mixture increased triacylglycerols, VLDL-cholesterol and ALP activity. In opposition, HDL-cholesterol levels decreased in broilers fed microalga alone (p = 0.002). Regarding hepatic composition, the inclusion of C. vulgaris in broiler diets, individually or combined with exogenous CAZymes, had a minor effect on fatty acids but improved the n-6/n-3 ratio and total carotenoids. Conclusions: In summary, the inclusion of a high level (10%) of C. vulgaris in broiler´s diet, regardless of the presence of exogenous CAZymes, improved hepatic antioxidant composition and did not impair broiler’s performance. In addition, the feed supplementation with CAZymes increased broilers lipemia. Therefore, dietary C. vulgaris at this incorporation level seems to be safe for animal health and do not compromise performance traits, with no need of CAZymes supplementationinfo:eu-repo/semantics/publishedVersio

Effect of dietary inclusion of Spirulina on production performance, nutrient digestibility and meat quality traits in post-weaning piglets

The effect of Spirulina (Arthrospira platensis), individually or in combination with two commercial carbohydrases, in piglet diets was assessed on growth performance, nutrient digestibility and meat quality traits. Forty post-weaned male piglets from Large White × Landrace sows crossed with Pietrain boars with an initial live weight of 12.0 ± 0.89 kg were used. Piglets were assigned to one of four dietary treatments (n = 10): cereal and soya bean meal base diet (control), base diet with 10% Spirulina (SP), SP diet supplemented with 0.005% Rovabio® Excel AP (SP + R) and SP diet supplemented with 0.01% lysozyme (SP + L). Animals were slaughtered after a 4-week experimental period. Growth performance was negatively affected by the incorporation of Spirulina in the diets, with an average decrease of 9.1% on final weight, in comparison with control animals. Total tract apparent digestibility (TTAD) of crude protein was higher (p < .05) in the control group than in other groups. In addition, lysozyme increased TTAD of crude fat and acid detergent fibre, relative to the SP and control groups, respectively. In addition, the incorporation of Spirulina, individually and supplemented with enzymes, did not impair meat quality traits. Surprisingly, no protective effect against lipid oxidation was observed with the inclusion of Spirulina in pork after 7 days of storage. This study indicates that growth performance of post-weaning piglets was impaired by the incorporation of 10% Spirulina in the diets, which is mediated by an increase in digesta viscosity and a lower protein digestibility, as a consequence of the resistance of microalga proteins to the action of endogenous peptidases. In addition, it also indicates that lysozyme, in contrast to Rovabio® Excel AP, is efficient in the degradation of Spirulina cell wall in piglet's intestine. However, the digestion of proteins liberated by Spirulina cell wall disruption is still a challengeinfo:eu-repo/semantics/publishedVersio

Alquilação de bases púricas e pirimídicas por iodetos de alquilo : estudos experimentais e teóricos

Tese de doutoramento em Farmácia (Química Farmacêutica), apresentada à Universidade de Lisboa através da Faculdade de Farmácia, 2007A presente dissertação descreve o estudo experimental e teórico da alquilação de purinas, pirimidinas e outras bases azotadas estruturalmente relaccionadas, e das suas dependências funcionais em ordem à temperatura, aos reagentes (agente alquilante e base) e ao ambiente solvolítico. Seleccionou-se um conjunto de bases azotadas heterocíclicas estruturalmente relacionadas com as bases púricas e pirimídicas mais comuns no material genético (a adenina, a guanina, a timina, a citosina e o uracilo). Os agentes alquilantes utilizados neste estudo foram o iodeto de metilo e o iodeto de etilo, devido às suas reconhecidas e comprovadas potencialidades mutagénicas e cancerígenas. Os meios polar prótico e dipolar aprótico utilizados foram, respectivamente, os solventes puros metanol e N,N-dimetilacetamida. Na alquilação das bases por iodetos de alquilo ocorre a formação de um produto N-alquilado, por um mecanismo reaccional do tipo ANDN (ou SN2). Da reacção de alquilação resulta a formação de um par iónico solvatado quantificado por condutimetria, o que permitiu obter experimentalmente coeficientes de velocidade, k, com elevado rigor a diversas temperaturas (no intervalo de 298,15 a 328,15 K). Do conjunto devalores de k obtidos calcularam-se as funções termodinâmicas de activação, Δ+Go, Δ+Ho e Δ+So, e estabeleceram-se relações extratermodinâmicas, nomeadamente relações isocinéticas e isoselectivas, no intuito de estudar o binómio estrutura-reactividade e caracterizar o mecanismo reaccional dos diferentes sistemas químicos estudados. No sentido de tentar esclarecer alguns aspectos mais específicos do percurso reaccional da alquilação, os estudos experimentais foram complementados com o estudo teórico da reacção de alquilação do 2-amino-1-metilbenzimidazol com iodeto de metilo em fase gasosa e em solução. Esta reacção foi seleccionada como modelo pelas suas semelhanças estruturais com as bases de núcleo purínico e foi estudada teoricamente a dois níveis quânticos tendo o solvente sido descrito de acordo com o modelo contínuo de polarização. A análise conjunta dos resultados, experimentais e teóricos, pelas diferentes metodologias analíticas de avaliação das dependências funcionais estudadas permitiu esclarecer a intervenção determinante, no mecanismo e cinética de alquilação das nucleobases, dos grupos substituintes em posição orto relativamente ao átomo de azoto endocíclico alquilado. Os resultados obtidos poderão servir de suporte para o desenvolvimento futuro de moléculas anti-metilantes não tóxicas capazes de desempenhar uma função importante na prevenção de lesões nos componentes intracelulares por reacções de alquilação.The present dissertation describes the work developed by both experimental and theoretical studies on the alkylation reactions of purines, pyrimidines and related nitrogen bases. We studied the effect of temperature, reactants (nitrogen base and alkylating agent) and solvent on the reaction mechanism. A set of nitrogen heterocyclic bases, structurally related to the most common purines and pyrimidines bases of the genetic material (adenine, guanine, thymine, cytosine and uracil), was selected. As alkylating agents we used methyl and ethyl iodides, for its recognized and proven mutagenic and carcinogenic potentialities. The polar-protic and dipolar aprotic environments were promoted using methanol and N,N-dimethylacetamide as solvents. In the alkylation of the selected bases with alkyl iodides occurs formation of an N-alkylated product, whose reaction mechanism can be describe as being of type ANDN (or SN2). To obtain accurate second-order rate constants, k, covering the range 298,15 to 328,15 K, we used the conductimetric technique. From the set of gotten values of k we calculate the thermodynamic functions of activation, Δ+Go, Δ+Ho and Δ+So, and established extrathermodynamic relations, such as, isokinetic and isoselective, in order to study the structure-reactivity relationships and characterize the reaction mechanism of the studied reactions. The alkylation of 2-amino-1-methylbenzimidazole with methyl iodide, is analysed using a theoretical approach at two different quantum levels. This nitrogen base was selected for its similarity in structure and size with nucleobase purine. The mechanism of this reaction was investigated both in gas phase and in solution. Two different quantum levels were used in the calculations and the solvent environment was modeled by continuum solvation methods. The results obtained by both experimental and theoretical approaches allowed clarifying the role of the substituent groups, in position ortho relatively to the alkylated endocyclic nitrogen atom, in the kinetic and reaction mechanism of the alkylation of nucleobases. Our results may support the development of non-toxic anti-methylation drugs able to prevent damages in the intracellular components due to alkylation reactions

Enzymatic Synthesis of the Flavone Glucosides, Prunin and Isoquercetin, and the Aglycones, Naringenin and Quercetin, with Selective α-L-Rhamnosidase and β-D-Glucosidase Activities of Naringinase

The production of flavonoid glycosides by removing rhamnose from rutinosides can be accomplished through enzymatic catalysis. Naringinase is an enzyme complex, expressing both α-L-rhamnosidase and β-D-glucosidase activities, with application in glycosides hydrolysis. To produce monoglycosylated flavonoids with naringinase, the expression of β-D-glucosidase activity is not desirable leading to the need of expensive methods for α-L-rhamnosidase purification. Therefore, the main purpose of this study was the inactivation of β-D-glucosidase activity expressed by naringinase keeping α-L-rhamnosidase with a high retention activity. Response surface methodology (RSM) was used to evaluate the effects of temperature and pH on β-D-glucosidase inactivation. A selective inactivation of β-D-glucosidase activity of naringinase was achieved at 81.5∘C and pH 3.9, keeping a very high residual activity of α-L-rhamnosidase (78%). This was a crucial achievement towards an easy and cheap production method of very expensive flavonoids, like prunin and isoquercetin starting from naringin and rutin, respectively