4 resultados para mechanism of salt tolerant

em Repositório Científico da Universidade de Évora - Portugal


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Meat industry needs to reduce salt in their products due to health issues. The present study evaluated the effect of salt reduction from 6% to 3% in two Portuguese traditional blood dry-cured sausages. Physicochemical and microbiological parameters, biogenic amines, fatty acids and texture profiles and sensory panel evaluations were considered. Differences due to salt reduction were perceptible in a faint decline of water activity, which slightly favoured microbial growth. Total biogenic amines content ranged from 88.86 to 796.68 mg kg 1 fresh matter, with higher amounts, particularly of cadaverine, histamine and tyramine, in low-salt products. Still, histamine and other vasoactive amines remained at low levels, thus not affecting consumers’ health. Regarding fatty acids, no significant differences were observed due to salt. However, texture profile analysis revealed lower resilience and cohesiveness in low-salt products, although no textural changes were observed by the sensory panel. Nevertheless, low-salt sausages were clearly preferred by panellists.

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The use of organic molecules as catalysts for the ring-opening polymerization (ROP) of cyclic esters has gained much interest last years.[1] The use of a molecule of biological interest, able to initiate ROP of cyclic esters without any cocatalyst is even more interesting, as the resulting material will not contain any catalytic residue. Nucleobase-polymer conjugates development is thus an emerging area envisaging biomedical applications.[2] However, they are usually synthesized by tedious multistep procedures. Recently, adenine was used as organoinitiator for the ROP of L-lactide.[3] Reaction conditions involving short reaction times and relatively low temperatures enable the access to adenine-polylactide(Adn-PLA)conjugates in a simple one-step procedure, without additional catalyst and in the absence of solvent. In this study, computational investigations with density functional theory (DFT) were performed in order to clarify the reaction mechanism leading to the desired Adn-PLA. The results show that a hydrogen bond catalytic mechanism, involving a nucleophilic attack of the activated amine group of adenine onto the carbonyl group of lactide, seem to be plausible.

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Health issues such as cardiovascular disease are often due to dietary habits. Thus, meat industry needs to reduce salt in their products. However, production of low-salt content dry-cured not affected. The current study evaluated the effect of salt reduction from 6% to 3% in two Portuguese traditional blood dry-cured sausages. Physicochemical and microbiological parameters, biogenic amines content, fatty acids profile, texture profile analyses and sensory panel evaluations were considered. Differences due to salt reduction were noticeable in a faint increase in water activity, which slightly favoured microbial growth, with the highest yeasts numbers found in 6% salt sausages. Total biogenic amines content ranged from 224.72 to 1302.81 mg kg-1 dry matter, with higher amounts, particularly of cadaverine, histamine and tyramine, in low-salt products. Still, histamine significant differences were observed due to salt content. However, texture profile analysis revealed that low-salt products showed lower resilience and cohesiveness, even though no textural changes were observed by the panellists. Nevertheless, low-salt sausages were clearly preferred. Still, taking the safety of these traditional meat products into account, the results obtained for pH, aw and biogenic amines, have shown that a reduction in salt content should be accompanied by complementary safety measures, such as the use of starter cultures to minimise microbiological and chemical risks.

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The present study evaluated the effect of salt reduction on traditional dry-cured sausages' safety, quality and product acceptance, comprising physicochemical and microbiological parameters, biogenic amines, fatty acids, texture profile and sensory analysis. According to our results, salt content had a major effect on microbiological counts, although not compromising the products' safety. Marked differences were identified regarding biogenic amines, in particular for histamine, tyramine and cadaverine, which were detected in larger amounts in products with 3%. Moreover, significant differences in the fatty acids profile have also been found, but only in less abundant components such as linoleic, lauric and heneicosanoic acids. Texture profile analysis of low-salt products, revealed a decrease in hardness and chewiness, along with an increase in adhesiveness values. Sensory evaluations revealed that despite the less intense aroma, products with 3% salt, had a more balanced salt perception. Our results suggest that salt content may be reduced to 50% in dry-cured products, with the obvious health-related advantages.