Effect of inulin/kefiran mixture on the rheological and structural properties of mozzarella cheese.

The relationships between chemical, textural, rheological and microstructural properties of low fat mozzarella cheese incorporated with different ratios of inulin/kefiran mixture were studied. By increasing inulin content, the protein and moisture content was increased and as a result, the meltability was reduced. Although, textural properties of low-fat mozzarella was completely influenced by inulin incorporation and hardness was increased, but the lower springiness and higher cohesiveness of cheese was achieved at high level of inulin which may be related to the increase in moisture and protein. Rheological properties of low-fat mozzarella cheese confirmed its shear-thinning behavior in which the G' value was more than G″. Mechanical properties of cheese showed that inulin incorporation into cheese did not significantly change the rheological properties of the cheese matrix. Consequently, the formation of a more rigid and cross-linked protein structure which is less plasticized achieved at high inulin incorporation through keeping more water and protein and less fat content. SEM results indicated the sponge honeycomb structure of mozzarella cheese which clearly confirmed the textural and rheological properties and there was an interrelationship among chemical, textural, rheological and microstructural properties of low-fat mozzarella cheese incorporated at different ratios of inulin.

Total phenolic compounds and antioxidant activity of Stachys turcomanica / Compostos fenólicos totais e atividade antioxidante da Stachys turcomanica

The subject of free radicals and their effects on biological systems is an important problem in Medicine. Antioxidants can protect biological systems against free radicals. In this study, the effect of methanol ratio (0, 20, 50, 80, and 100%) in water on extraction yield of Total phenolic (TP) compounds and antioxidant activity (AA) of Stachys turcomanica extract were evaluated. The amount of TP compounds were determined using Folin-Ciocalteu reagent, and AA measured by 2, 2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and betacaroten linoleic acid methods. The results showed extraction of phenolic compounds and their AA were affected by solvent combinations. In addition, there was a good correlation between TP content and AA of Stachys turcomanica extracts. Finally the methanol: water (80:20) was good solvent in extracting of phenolic compounds with highest AA.

O tema dos radicais livres e seus efeitos nos sistemas biológicos é um problema importante na medicina. Os antioxidantes podem proteger os sistemas biológicos contra os radicais livres. Neste estudo, avaliou-se o efeito da proporção de metanol (0, 20, 50, 80 e 100%) na água com o rendimento de extração de compostos fenólicos totais (TP) e atividade antioxidante (AA) do extrato Stachys turcomanica. A quantidade de compostos de TP foi determinada utilizando o reagente de Folin-Ciocalteu, e AA medido por 2, 2-difenil-1-picrilidrazilo (DPPH), poder antioxidante redutor férrico (FRAP) e ácido beta-caroten ácido linoleico. Os resultados mostraram a extração de compostos fenólicos e os seus AA foram afetados por combinações de solventes. Além disso, houve uma boa correlação entre o conteúdo de TP e os extratos de AA de Stachys turcomanica. Finalmente, o metanol: água (80:20) foi bom solvente na extração de compostos fenólicos com AA mais alto.