Search

Desalination concentrate (DC) is a potential medium for microalgal cultivation since it contains an abundance of mineral salts. In this study, the feasibility of growing Chlorella vulgaris with DC was evaluated and the influence of DC concentration on the growth, biomass productivity, and biochemical composition was assessed. Media comprised of DC mixed with bold basal medium (BBM) in different concentrations were prepared for microalga cultivation. A sequential statistical methodology, comprising fractional factorial design and response surface methodology (RSM) was applied to enhance the biomass production. The growth of C. vulgaris was promoted with 75 % BBM + 25 % DC compared with the BBM control. C. vulgaris biomass production (0.59 g L−1) was observed with 75 % BBM + 25 % DC with optimal concentrations of sodium nitrate (0.09 g L−1), monobasic potassium phosphate (0.014 g L−1), and micronutrient solution (0.20 mL L−1). The gradual increase of DC had a strong effect on the biochemical composition of C. vulgaris. Carbohydrate fiber and protein contents were estimated to be 14.4 and 51.3 %, respectively, when the microalgae were cultivated in 75 % BBM + 25 % DC. The lipid content (12.5 %) of C. vulgaris cells was highest at the optimized BBM DC concentrations. When grown in the BBM control and optimized BBM + DC media, C. vulgaris produced lipids rich in polyunsaturated fatty acids (C18:3 ω3) and monounsaturated fatty acids (C18:1). These results indicated that DC is a feasible alternative for the mass cultivation of C. vulgaris.

This work examined the parameters of color, transparency, water solubility, wettability and surface free energy of chitosan/ydroxypropylmethylcellulose (HPMC) blends plasticized with sorbitol. The solutions of chitosan and hydroxypropylmethylcellulose were mixed in different proportions (100/0; 70/30; 50/50; 30/70 and 0/100 respectively), and 20 mL was casting in Petri dishes to posterior analysis of formed films. The CIELab method was used to determine the L ⁎, a ⁎ and b ⁎ color values of the samples. The color was affected by different proportion of chitosan/hydroxypropylmethylcellulose. The higher the HPMC proportion in the films, the higher the solubility in water. Contact angle measurements showed an increment in the values of the polar surface free energy and the hydrophilic character when HPMC component was increased in the blend.

International audience; Amphiphilic polymers are synthesized from various biobased compounds involving telomerization of glycerin-derived acrylate monomers with mercaptan-modified fatty acids. The effects of the chemical structure of the saturated or unsaturated hydrophobic block are investigated. Dynamic and static light scattering measurements, transmission electronic microscopy, and atomic force microscopy observations show that these copolymers are capable of self-assembling into nanosized spherical particles in aqueous solution, made from compound micelles. The critical micellar concentration of these polymers is in the range of 10-60 mg L−1 determined by fluorescence. These biobased polymers could have applications in various industrial fields, such as cosmetics and agrochemicals.

In this work, the structural, mechanical, diffractometric, and thermal parameters of chitosan-hydroxypropylmethylcellulose (HPMC) films plasticized with sorbitol were studied. Solutions of HPMC (2% w/v) in water and chitosan (2% w/v) in 2% acetic acid solution were prepared. The concentration of sorbitol used was 10% (w/w) to both polymers. This solutions were mixed at different proportions (100/0; 70/30; 50/50; 30/70, and 0/100) of chitosan and HPMC, respectively, and 20 mL was cast in Petri dishes for further analysis of dried films. The miscibility of polymers was assessed by X-ray diffraction, scanning electronic microscopy (SEM), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). The results obtained indicate that the films are not fully miscible at a dry state despite the weak hydrogen bonding between the polymer functional groups. Neste trabalho, os parâmetros estruturais, mecânicos, difratométricos e térmicos de filmes de quitosana e hidroxipropilmetilcelulose (HPMC), plastificados com sorbitol, foram estudados. Soluções de HPMC (2% m/m) em água, e quitosana (2% m/m) em uma solução de ácido acético 2%, foram preparadas. A concentração de sorbitol usada foi de 10% (m/m) para ambos os polímeros. Estas soluções foram misturadas em diferentes proporções (100/0; 70/30; 50/50; 30/70 e 0/100) de quitosana e HPMC, respectivamente, e 20 mL foram vertidos em placas de Petri de poliestireno, para posterior análise dos filmes prontos. A miscibilidade dos polímeros foi avaliada através da Difração por Raio-X, Microscopia Eletrônica de Varredura, Calorimetria Exploratória Diferencial (DSC) e Análise Termogravimétrica (TGA). Através dos resultados obtidos, os filmes não são totalmente miscíveis no estado seco, embora existam ligações fracas de hidrogênio entre os grupos funcionais dos biopolímeros.

Filés de peito de frango foram adicionados de salmouras contendo proteína isolada de soja (PIS), tripolifosfato de sódio (TPS) e sal (NaCl), com o objetivo de avaliar as características físico-químicas das carnes. Em cada um dos oito tratamentos realizados, trinta fi lés passaram por injeção em máquina múltiplo-injetora e posterior tambleamento, onde quantidades diferentes de PIS e de um preparado contendo 65% de TPS e 35% de sal foram adicionados. A PIS foi adicionada em proporções de 4% ou 8% e a mistura de TPS+sal foi adicionada em proporções de 5% ou 10%. Foram realizadas avaliações gravimétricas para obtenção do percentual de absorção de salmoura pelos cortes e, após o congelamento e armazenamento dos cortes, realizou-se análises físico-químicas de pH, umidade, proteína, extrato etéreo, resíduo mineral fi xo, sódio e fosfato. Para a avaliação estatística dos resultados, foi realizada a análise de variância (ANOVA) complementada pelo Teste de Comparações Múltiplas de Tukey. Os dados de absorção média nos oito tratamentos variaram de 6,70% a 9,24%. Quanto às análises físico-químicas, as amostras apresentaram resultados de pH que variaram de 5,96 a 6,28; umidade de 75,64g/100g a 77,34g/100g, proteína de 20,55g/100g a 21,68g/100g e relação umidade/proteína (RUP) de 3,49 a 3,75; extrato etéreo de 0,69g/100g a 1,47g/100g; resíduo mineral fi xo de 0,99g/100g a 1,67g/100g; sódio de 62,40mg/100g a 395,08mg/100g; e fosfato de 494,64mg/100g e 730,31mg/100g. Os dados de absorção não apresentaram diferença signifi cativa entre os tratamentos. As análises de umidade, proteína, RUP e gordura, apesar de fornecerem resultados diferentes significativamente (p