Content: Different tanning materials endow leather with varying colors observable in undyed leathers. Periodateoxidized starch tanned leathers have a yellow tinge or light brown color and get darker with age. The color change in situ is ascribable to iodate ions that are byproducts of periodate oxidation. Iodate ions undergo reduction to form iodine molecules that are yellow or brown in low or at higher concentrations. This study focuses on the removal of iodate ions from Dialdehyde Tapioca Starch (DTS) using a simple precipitation method. Preparation of DTS is by periodate oxidation and precipitation of iodate ions using an inorganic precipitant. The experiments for manufacturing wet-white leathers used pickled goatskins and DTS (unmodified and modified) tanning agents at various percentages based on pelt weight. Glutaraldehyde (GTA) tanning was the control. The percentage removal of iodate ions in modified DTS was 98%. Both unmodified and modified DTS had an aldehyde content of 70%. FT-IR and 1H-NMR confirmed the aldehyde groups. GTA, unmodified, and modified DTS tanned leathers had shrinkage temperatures of 80, 87, and 89°C, respectively. The physico-mechanical properties of the control and experimental leathers are comparable. GTA tanned leather had the typical brown color associated with GTA tannages. The ‘b’ color value of unmodified DTS tanned leather was high confirming yellowing of leathers upon ageing. Wet-white leather tanned with modified DTS had no discernible color change. Analysis of the spent tan liquor shows a reduction in the BOD, COD, TS, and TDS load when compared to GTA tanning system evincing the biodegradability of DTS. This study has overcome the drawback associated with periodate-oxidized starch tanning agents, viz. leather darkening over time, considering the chemical and physico-mechanical properties of the resultant leathers. The novel iodate free DTS can be scaled-up for commercial availability. Take-Away: Removal of iodate ions from periodate-oxidized starch before its use as a tanning agent is imperative to avoid leather color change over time. This study reports the successful removal of iodate ions from Dialdehyde Tapioca Starch (DTS). Wet-white leather tanned with the modified DTS had no observable color change upon ageing.

Made available in DSpace on 2017-07-21T18:53:23Z (GMT). No. of bitstreams: 1 Doris Oliveira Gregianin.pdf: 1718205 bytes, checksum: 59a8cb966255e87e0fa3f347f2a191cb (MD5) Previous issue date: 2014-08-28 / The increased incidence of cardiovascular disease and various cancers have been the cause of searching for changing habits in a large portion of the population, seeking the physical activity in conjunction with the consumption of healthier foods with higher nutritional content. Considering the high biological value of the proteins of sweet whey and the recognized effect in reducing risk of cardiovascular disease of soy protein, the aim of this study was to develop a mixed chocolate-soluble soybean extract dissolved in sweet whey. The different proportions of carrageenan stabilizers, pectin and tapioca starch were defined by the experimental design of mixtures simplex centroid. By optimizing the response surface was definitely the best formulation in relation to the physic-chemical and sensory parameters. The simultaneous optimization of response variables indicated that the optimal formulation should contain 46% carrageenan and 54% pectin and 0% starch, with a desirability index of 0.929. The formulation indicated for the desirability function was made with water soluble soy extract dissolved in sweet whey and; on sweet whey with reduced lactose content. Serum was hydrolyzed by the action of lactase from Kluyveromyces lactis yeast enzyme at a concentration of 2500 NLU / L in reaction 4 hr at 37 ° C. The sensory attributes were evaluated by nine points hedonic scale and attitude scale in purchase intent. For overall impression, the formulations presented average value of 7.11 ±1.09, while purchase intent the average value was 3.99 ± 1.28, and the multiple regression models proved to be predictive. The most widely accepted formulations were those who had lower viscosity and instrumental containing pectin in its constitution. The results obtained indicate that the combination of sweet whey and soy aqueous extract is a viable option for the preparation of a chocolate beverage. It was also observed that the use of cassava starch as a thickener does not interfere negatively on the rheological and sensory characteristics and; that the combined carrageenan and pectin concentrations defined predictive model ensures greater acceptability of the product. / O aumento da incidência de doenças cardiovasculares e diversos tipos de câncer tem sido a causa da procura por mudanças de hábitos em grande parte da população, buscando-se a prática de atividades físicas em conjunto com o consumo de alimentos mais saudáveis, com maior valor nutricional. Considerando o alto valor biológico das proteínas do soro de leite doce e o reconhecido efeito na diminuição de risco de doenças cardiovasculares da proteína de soja, o objetivo deste trabalho foi desenvolver um achocolatado misto de extrato hidrossolúvel de soja dissolvido em soro de leite doce. As diferentes proporções dos estabilizantes carragena, pectina e amido de mandioca foram definidas pelo planejamento experimental de misturas simplex centróide. Através da otimização da Superfície de Resposta foi definida a melhor formulação em relação aos parâmetros físico-químicos e sensoriais. A otimização simultânea das variáveis de resposta indicou que a formulação ideal deveria conter 46% de carragena e 54% de pectina e 0% de amido, com um índice de desejabilidade de 0,929. A formulação indicada pela função de desejabilidade foi elaborada com extrato hidrossolúvel de soja dissolvido em soro de leite doce e; em soro doce com teor de lactose reduzido. O soro foi hidrolisado pela ação da enzima lactase proveniente da levedura Kluyveromyces lactis, na concentração de 2.500 NLU/L numa reação de 4 horas à temperatura de 37°C. Os atributos sensoriais foram avaliados pela escala hedônica de nove pontos e escala de atitude na intenção de compra. Para impressão global as formulações apresentaram valor médio 7,11 ±1,09, enquanto que para intenção de compra o valor médio foi de 3,99 ±1,28, sendo que os modelos de regressão múltipla mostraram-se preditivos. As formulações mais aceitas foram aquelas que apresentaram menor viscosidade instrumental e que continham pectina em sua constituição. Os resultados obtidos indicam que a combinação do soro doce de leite e extrato aquoso de soja é uma opção viável para a elaboração de uma bebida achocolatada. Também foi possível observar que o uso do amido de mandioca como espessante não interfere negativamente nas características reológicas e sensoriais do produto e; que a carragena e pectinas combinadas, nas concentrações definidas pelo modelo preditivo, garantem maior aceitabilidade ao produto.