Abstract The aim of this study was to develop snack bars nutritionally enriched with Spirulina and evaluate if there was acceptance of the sensorial attributes by schoolchildren. Snack bars enriched with Spirulina (2% and 6%) and a control formulation (0% Spirulina) were prepared. The samples were evaluated regarding nutritional content, microstructure, and sensorial characteristics. Furthermore, the study of stability during storage (30 days) was carried out. The addition of 2% and 6% of Spirulina provided a protein increase of 11.7% and 29.9%, respectively. The physicochemical and microbiological parameters remained stable during the storage of 30 days. Sensory evaluation showed that snack bars enriched with 6% Spirulina presented no significant difference (p > 0.05) compared to the control samples. We concluded that Spirulina can be used as a nutritive ingredient in snack bars designed for infant feeding without sensorial characteristics change.

Abstract Carotenoids have a low solubility in water, and therefore their incorporation in foods is impaired. The nanoemulsions are able to protect these compounds and enhance bioavailability. The objective of this study was to develop nanoemulsions with added beta-carotene, evaluating the influence of process variables and the stability at a long storage period. To assess the effects of these variables a Box-Behnken design was performed. The best condition to form a stable emulsion was 7% (w.w-1) of surfactant and 40 °C. All formulations subjected to a thermal stress test remained stable after the test. The use of a higher concentration of soy lecithin (7%, w.w-1) in the development of emulsions conferred greater stability after a freeze-defrost cycle. Furthermore, with this concentration of surfactant, and using a high-speed homogenizer under conditions of 10,000 rpm, 30 °C, and 20 min of shaking time, it was possible to develop stable nanoemulsion with an average diameter of 429 nm. Moreover, the zeta potential indicated system stability. Thus, it was possible to obtain stable nanoemulsion without the use of subsequent equipment, which makes the process less expensive.

Abstract The biological assimilation of the sugars present in lignocellulosic residues has gained prominence since these residues are the most abundant and economic residues in nature. Thus, the objective of this work was to determine whether the use of D-xylose and L-arabinose as sources of carbon in Synechococcus nidulans and Spirulina paracas cultures affects the growth and production of proteins and carbohydrates. Kinetic growth parameters, pentose consumption, protein content and carbohydrates were evaluated. Synechococcus nidulans and Spirulina paracas consumed all concentrations of pentose used. The highest cellular concentration (1.37 g.L-1) and the highest protein productivity (54 mg.L-1.d-1) were obtained for Spirulina paracas, which was submitted to the addition of 38.33 mg.L-1 D-xylose and 1.79 mg.L-1 L-arabinose. The use of pentose promoted the accumulation of proteins for the studied microalgae. This is one of the first works to report protein bioaccumulation as a result of pentose addition.

ABSTRACT Spirulina is a microalgal genre that has the capacity to produce various bioproducts with applications in several areas including the energy sector. The study aimed to assess the ability of CO2 biofixation, biodiesel and other biocompounds production by Spirulina sp LEB 18 cultured in air-lift photobioreactor. The microalgae presented a rich macronutrient composition: protein (47.3%), carbohydrates (13.4%) and a high lipid content (32.7%) in a media with nitrogen reduction, CO2 using air-lift photobiorector. Furthermore, 160 mg.L.d-1 of CO2 was biofixed, generating a maximum biomass yield of 0.02 g.L.d-1. The lipids evaluated for biodiesel production presented a theoretical yield of 19.8% for in situ transesterification and 47.9% for conventional transesterification. The microalgal biomass has potential for producing biodiesel that can be applied instead or in mixture with traditional diesel fuel. The study of obtaining energy associated with the production of other high value-added biocompounds from the microalgal biomass is of high importance because in this way, the viability of biofuel production by this microorganism can be increased.

Abstract This study was conducted to develop PCL nanofibers with the incorporation of microalgae biopeptides and to evaluate the stability of chicken meat cuts during storage. PCL and PCL/biopeptides nanofibers were formed by electrospinning method, and the diameters obtained were 404 and 438 nm, respectively. The tensile strength, elongation, melting temperature and thermal stability of biopeptide-added PCL nanofibers were 0.245 MPa, 64%, 56.8 °C and 318 °C, respectively. PCL/biopeptide nanofibers showed a reducing power of 0.182, inhibition of 22.6% and 12.4% for DPPH and ABTS radicals, respectively. Chicken meat cuts covered by the PCL/biopeptide nanofibers showed 0.98 mgMDA∙kg-1 and 25.8 mgN∙100g-1 for TBARS and N-BVT analysis, respectively. Thus, the PCL/biopeptide nanofibers provided greater stability to the product and control of oxidative processes ensuring the product quality maintenance during the 12 d of storage.

Abstract Microalgae are studied because of their biotechnological potential. The growth of microalgae aims at obtaining natural compounds. Due to the large amount of accumulated polymer waste, one of the solutions is the use of biodegradable polymers. The objective of this work was to select biopolymer-producing microalgae and to study the cell growth phase in which maximum production occurs. Microalgae Cyanobium sp., Nostoc ellipsosporum, Spirulina sp. LEB 18 and Synechococcus nidulans were studied. The growth was carried out in closed 2 L photobioreactors kept in a chamber thermostated at 30 °C with an illuminance of 41.6 μmolphotons.m-2.s-1 and a 12 h light/dark photoperiod. The biopolymers were extracted at times of 5, 10, 15, 20 and 25 d. The microalgae that had the highest yields were Nostoc ellipsosporum and Spirulina sp. LEB 18 with crude biopolymer efficiency of 19.27 and 20.62% in 10 and 15 d, respectively, at the maximum cell growth phase.

Abstract Nowadays the demand for practical food like snacks increases worldwide, however the nutritional value in most these formulations is reduced. Due to its chemical composition with high protein concentration, the microalga Spirulina has been used on the production of enriched foods. The present study aimed to evaluate the effects of Spirulina sp. LEB 18 addition on snacks formulations and extrusion conditions on the physicochemical and structural properties of snacks. Protein concentration and physical properties such as expansion index, bulk density, hardness, water absorption index, water solubility index and color were determined. The results showed that the addition of Spirulina sp. LEB 18, temperature in the last zone of the extruder and feed moisture influenced the product responses. The increase in feed moisture increased the hardness, bulk density and water absorption index of the snacks. Higher concentrations of microalga produced snacks with higher protein content, total color difference (ΔE) and compact structure. The addition of 2.6% Spirulina produced snacks with up to 11.3% protein and with adequate physical and structural properties for consumption. Thus, snacks containing Spirulina are an alternative to the demand for healthy food of practical consumption.

ABSTRACT Nanofibers are materials that present high elasticity, strength, porosity and surface-area-to-volume ratio. The electrospinning method is the most widely adopted technique for forming polymeric nanofibers due to repeatability, easy scale-up process and production of long and continuous nanofibers. This method produces nanofibers with diameters ranging from 10 nm to 1000 nm. The process is regulated by many parameters which significantly affecting the morphology of the nanofibers, and through the proper handling of these parameters are obtained desired nanofibers in morphology and diameters. Based on this, the objective of this work was to evaluate the size and morphology of nanofibers obtained by different conditions of the electrospinning process. The electrospinning technique will be utilized to produce nanofibers with polyacrylonitrile (PAN) polymer and solvent N, N-dimethylformamide (DMF). The polymer solutions (10% (w/v)) were injected through of the capillary with diameter 0.45; 0.55; 0.70 and 0.80 mm. The distances from the collector to the capillary were tested between 100 and 200 mm, voltage between 15 and 25 kV, and feed rate of the solution between 100 and 1000 µL/h. All of the tests were conducted at 22 °C with the relative humidity level controlled at 65±1%. The morphology and size of nanofibers were evaluated by Scanning Electron Microscopy (SEM). Thus, the development of nanofibers with small diameter and high pore volume facilitate bioactive molecules loading and / or transport of nutrients and wastes, and allow the polymeric nanofibers become important class of biomaterials.

ABSTRACT The aim of this study was to analyze the influence of solid waste on the cultivation of the microalgae Spirulina sp. LEB 18 and Chlorella fusca LEB 111 with 0, 40, 80 and 120 ppm of mineral coal ash. The addition of the ash did not inhibit the cultivation of microalgae at the tested concentrations, showing that it could be used for the cultivation of these microalgae due to the minerals present in the ash, which might substitute the nutrients needed for their growth.

The objective of this study was to extract poly(3-hydroxybutyrate) (PHB) from the microalgal biomass of Spirulina LEB 18 for the development of nanofibers by electrospinning method. Different extraction methods were tested. The maximum yield obtained was 30.1 ± 2%. It was possible to produce nanofibers with diameters between 826 ± 188 nm and 1,675 ± 194 nm. An increase in the nanofiber diameter occurred when a flow rate of 4.8 μL min-1 and a capillary diameter of 0.90 mm were used. The nanofibers produced had up to 34.4% of biomass additives, i.e., non-PHB materials. This can be advantageous, because it enables the conservation of microalgal biomass compounds with bioactive functions.

As microalgas são consideradas fontes potenciais de diversos compostos químicos. Os ácidos graxos obtidos da biomassa podem apresentar efeitos terapêuticos em humanos e podem ser usados para produção de biodiesel. Objetivou-se, neste trabalho verificar o conteúdo lipídico e o perfil dos ácidos graxos das microalgas Spirulina sp., Scenedesmus obliquus, Chlorella kessleri e Chlorella vulgaris cultivadas em diferentes concentrações de dióxido de carbono e bicarbonato de sódio. A microalga Chlorella kessleri cultivada com 12% de CO2 apresentou a maior concentração de lipídios na biomassa seca (9,7% p/p). A máxima concentração de ácidos graxos insaturados foi 72,0% (p/p) para C. vulgaris cultivada com 12% de CO2. Para os ácidos graxos saturados o maior valor encontrado foi 81,6% (p/p), quando a microalga Spirulina sp. foi cultivada com 18% de CO2 e 16,8 g.L-1 de bicarbonato de sódio.

Microalgae have a great potential as a source of several chemical compounds. The fatty acids have shown therapeutic effects and used to produce biodiesel. The aim of this work was to verify the lipid contents and the fatty acids profile of the microalga Spirulina sp., Scenedesmus obliquus, Chlorella kessleri and Chlorella vulgaris cultived in different carbon dioxide and sodium bicarbonate concentrations. The microalgae Chlorella kessleri cultived with 12% CO2 showed the highest lipid content in the dry biomass (9.7% p/p). The maximum unsaturated fatty acids concentration was 72.0% (p/p) to C. vulgaris in the culture with 12% CO2. The highest saturated fatty acids value was 81.6% (p/p) when microalga Spirulina sp. was cultived with 18% CO2 and 16.8 g.L-1 sodium bicarbonate.

The aim of this work was to study the removal of CO2 and NO by microalgae and to evaluate the kinetic characteristics of the cultures. Spirulina sp. showed µmax and Xmax (0.11 d-1, 1.11 g L-1 d-1) when treated with CO2 and NaNO3. The maximum CO2 removal was 22.97% for S. obliquus treated with KNO3 and atmospheric CO2. The S. obliquus showed maximum NO removal (21.30%) when treated with NO and CO2. Coupling the cultivation of these microalgae with the removal of CO2 and NO has the potential not only to reduce the costs of culture media but also to offset carbon and nitrogen emissions.