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.
ResumoA manteiga é um derivado lácteo que possui em sua composição 80% de gordura e que, quando consumido sem exagero, faz parte de uma alimentação equilibrada e saudável. Muitos estudos demonstram que uma porcentagem significativa da população mundial sofre com transtornos gastrointestinais quando consome leite e seus derivados, devido à intolerância à lactose. Além disso, há uma tendência crescente na área de alimentos para o desenvolvimento de produtos com reduzido teor de sódio, devido a inúmeras doenças provocadas pelo seu excesso no organismo. Nesse contexto, o objetivo deste trabalho foi desenvolver três formulações de manteiga extra, sem lactose e com diferentes concentrações de sódio, mantendo seus teores reduzidos. Foram realizados ensaios laboratoriais para a caracterização dos produtos, a fim de garantir os parâmetros físico-químicos e microbiológicos para manteiga, propostos pela legislação vigente (BRASIL, 1996). Além disso, foi realizada análise sensorial por meio de teste de aceitabilidade e intenção de compra. O teste de aceitabilidade demonstrou que a maioria dos julgadores atribuíram nota 8, equivalente a "gostei muito" na escala hedônica, às amostras A e B em relação a todos os atributos e, para a amostra C, nota 8 à textura e aceitabilidade global. A avaliação da intenção de compra atribuiu às amostras A, B e C, notas 4 e 5, correspondentes a "possivelmente compraria" e "certamente compraria" na escala (considerando que A = manteiga extra sem sal; B = manteiga extra salgada 0,75%; C = manteiga extra salgada 1,0%). O estudo demonstrou que é possível desenvolver produtos à base de leite, sem lactose e com reduzido teor de sódio, mantendo suas características nutricionais e sensoriais e com boa aceitabilidade de mercado.Palavras-Chave: Manteiga extra. Sem lactose. Redução de sódio.
Researches concerning cooling-lubrication optimization in grinding have been conducted to contribute to a more sustainable process. An alternative to flood coolant is minimum quantity lubrication (MQL), which spray oil droplets in a compressed air jet. However, problems related to wheel cleaning were reported, due to wheel loading by a mixture of chips and oil, resulting in worsening of surface quality. This work aims to evaluate the viability of Teflon and aluminum oxide for wheel cleaning, compared to MQL without cleaning and MQL with cleaning by compressed air, through the following output variables: surface roughness, roundness, wheel wear, grinding power and acoustic emission. Vickers microhardness measurements and optical microscopy were also carried out. The results showed that both materials were efficient in cleaning the wheel, compared to MQL without cleaning, but not as satisfactory as compressed air. Much work is to be done in order to select the right material for wheel cleaning.
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