Marine microalgae as a potential source of single cell protein (SCP)

[Abstract] The marine microalgae Tetraselmis suecica, Isochrysis galbana, Dunaliella tertiolecta and Chlorella stigmatophora are good biological sources of single cell protein (SCP). Protein content accounts for 39.12%–54.20% of the dry matter, D. tertiolecta having the highest. Lysine values are between 3.67 and 4.52 g/100 g of protein, and thus are higher than those for freshwater species. The total nucleic acid content is less than 7% of the dry matter; this value is definitely lower than that for yeasts or bacteria, commonly used as SCP sources. Amino acid profiles of the four species are very similar and comparable to the FAO reference protein, buth with a low content of methionine and cystine and a high content of lysine. The MEAA indices are between 81 and 84.98, without significant differences among the four species. Marine microalgae can be used as a potential SCP source

Comparison of extraction methods for selected carotenoids from macroalgae and the assessment of their seasonal/spatial variation

peer-reviewedNatural bioactives are an excellent source of carotenoids for the production of nutraceuticals, functional foods and food additives. The extraction efficiencies of solid-liquid extraction (SLE), supercritical CO2, supercritical CO2 with ethanol as co-solvent for the recovery of the carotenoids, xanthophyll and fucoxanthin, from two brown macroalgae Fucus serratus and Laminaria digitata were explored. The extraction efficiency was measured using both purity and yield of target compounds. Solid liquid extraction. (hexane/acetone (70:30) at 50 degrees C for 24 h produced the greatest yield of carotenoid rich extracts from F. serratus. Optimal conditions in terms of carotenoid yield using supercritical CO2 were 50 degrees C, 300 Atm with an extraction time of 60 min. SCO2 yielded a higher purity of fucoxanthin while SLE resulted in a higher purity of xanthophyll. Seasonal/spatial variation based on the purity and yield was also investigated to provide valuable information on optimal harvest time for these compounds. (C) 2016 Elsevier Ltd. All rights reserved.ACCEPTEDpeer-reviewe

Effect of the re-use of the osmotic solution on the stability of osmodehydro-refrigerated grapefruit

Osmotic dehydration (OD) of grapefruit (55 degrees Brix sucrose solution, 30 degrees C) was carried out to obtain 75 g water/100 g sample in the final product. Although the grapefruit was replaced each time, the osmotic solution (OS) was reused for five OD cycles, with or without pasteurization. The samples obtained in cycles 1, 3 and 5, were stored at 10 degrees C. Changes in degrees Brix, water content, water activity, pH, total acidity, ascorbic acid content, cation concentration, respiration rate and total microbial counts at different storage times were analyzed and compared to fresh-cut grapefruit stored under the same conditions. During OD, a partial loss of the natural soluble substances present in the fruit was observed. In terms of the dehydration level reached by the fruit, it is possible to reuse the OS in up to 5 OD, without any reconcentration treatment. Nevertheless, it is advisable to pasteurize the OS before each cycle in order to obtain a product with a shelf-life of between 7 and 12 days in refrigeration, depending on the number of cyclesThe authors thank the Ministerio de Ciencia y Tecnologia and the Fondo Europeo de Desarrollo Regional (FEDER) for the financial support throughout the project AGL2005-05994.Moraga Ballesteros, MJ.; Moraga Ballesteros, G.; Martínez Navarrete, N. (2011). Effect of the re-use of the osmotic solution on the stability of osmodehydro-refrigerated grapefruit. Food Science and Technology. 44(1):35-41. https://doi.org/10.1016/j.lwt.2010.05.018S354144

Combining biotechnology with circular bioeconomy: from poultry, swine, cattle, brewery, dairy and urban wastewaters to biohydrogen

ABSTRACT: The ability of microalgae to grow in nutrient-rich environments and to accumulate nutrients from wastewaters (WW) makes them attractive for the sustainable and low-cost treatment of WW. The valuable biomass produced can be further used for the generation of bioenergy, animal feed, fertilizers, and biopolymers, among others. In this study, Scenedesmus obliquus was able to remove nutrients from different wastewaters (poultry, swine and cattle breeding, brewery and dairy industries, and urban) with removal ranges of 95-100% for nitrogen, 63-99% for phosphorus and 48-70% for chemical oxygen demand. The biomass productivity using wastewaters was higher (except for poultry) than in synthetic medium (Bristol), the highest value being obtained in brewery wastewater (1025 mg/(L.day) of freeze-dried biomass). The produced biomass contained 31-53% of proteins, 12-36% of sugars and 8-23% of lipids, regardless of the type of wastewater. The potential of the produced Scenedesmus obliquus biomass for the generation of BioH(2) through batch dark fermentation processes with Enterobacter aerogenes was evaluated. The obtained yields ranged, in mL H-2/g Volatile Solids (VS), from 50.1 for biomass from anaerobically digested cattle WW to 390 for swine WW, whereas the yield with biomass cultivated in Bristol medium was 57.6 mL H-2/gvs.info:eu-repo/semantics/publishedVersio

Microalgae biomass as an additional ingredient of gluten-free bread: Dough rheology, texture quality and nutritional properties

Microalgae have been widely used as a source of functional ingredients such as pigments, antioxidants, vitamins, and omega-3 polyunsaturated fatty acids. They also represent a promising alternative source of protein. The objective of this study was to evaluate the impact of the addition of two green microalgae species (Nannochloropsis gaditana L2 and Chlamydomonas sp. EL5) on the techno-functional and nutritional properties of gluten-free bread. Microalgae biomass was added in the amounts of 1.0 and 3.0 g/100 g of flour. The behavior of the dough during the mixing as well as the physicochemical properties of the prepared breads were investigated. Gluten-free bread with N. gaditana L2 and Chlamydomonas sp. EL5 presented significantly higher protein and higher levels of lipids and ash, compared with the control bread. The incorporation of 3% microalgae biomass revealed a 100% increase in iron and calcium contents. The fatty acid profile of supplemented bread changed in a species-specific manner with a particular increase in linolenic acid (18:3 ω3) and a decrease in ω3/ω6 ratio. Besides, due to its original biochemical composition, mainly the highly protein content, microalgae incorporation was found to bring an overall structuring effect on the gluten-free bread texture. However, the dough mixing properties were not affected significantly by microalgae addition. A significant change in color was recorded in doughs, breads, crusts and crumbs. This was caused by the presence of pigment in microalgae biomass, which turned into more intense green-yellow tonalities. A sensory analysis revealed that the supplemented breads scored highest for nearly all the sensory parameters with the 3% N. gaditana L2 bread as the preferred one in terms of global appreciation. This innovative approach gives new insights of the possibility of improving gluten-free products, structurally and nutritionally, using only microalgae as a natural and a sustainable food ingredientinfo:eu-repo/semantics/publishedVersio

Hypoglycemic and hypolipidemic effects of Saururus chinensis Baill in streptozotocin-induced diabetic rats

Saururus chinensis Baill was reported to inhibit α-glucosidase in vitro and flatten postprandial increase in blood glucose in streptozotocin (STZ)-induced diabetic rats. We studied the effect of chronic consumption of S. chinensis Baill on blood glucose and lipid profile in STZ-induced diabetic male rats fed high fat diet. Male rats weighing 100-120 g were fed 30% fat diet with and without 10% freeze-dried leaves of S. chinensis Baill for 7 weeks after 1 week of adaptation. The rats were rendered diabetic by intravenous injection of STZ (60 mg/kg) after 6-week feeding of the assigned diets. At 1 week after the injection, the rats were sacrificed after an overnight fast. Plasma glucose (380.2 ± 14.4 mg/dL), total cholesterol (93.9 ± 7.9 mg/dL) and triglyceride levels (123.6 ± 7.5 mg/dL) of the S. chinensis Baill group were significantly lower than those of the control group (418.1 ± 12.0 mg/dL, 119.9 ± 9.4 mg/dL, 152.0 ± 10.3 mg/dL, respectively, p<0.05). Chronic consumption of S. chinesis Baill significantly decreased maltase activity of the small intestinal mucosa (120.1 ± 8.7 U/g protein) compared with the control group (96.8 ± 7.0 U/g protein, p<0.05). These results suggest that S. chinensis Baill have hypoglycemic and hypolipidemic effects by inhibiting α-glucosidase activity in the animal model of diabetes mellitus

Microalgae biomass as an alternative ingredient in cookies: sensory, physical and chemical properties, antioxidant activity and in vitro digestibility

Microalgae can be regarded as an alternative and promising food ingredient due to their nutritional composition, richness in bioactive compounds, and because they are considered a sustainable protein source for the future. The aim of this work was to evaluate microalgae (Arthrospira platensis F & M-C256, Chlorella vulgaris Allma, Tetraselmis suecica F & M-M33 and Phaeodactylum tricornutum F & M-M40) as innovative ingredients to enhance functional properties of cookies. Two biomass levels were tested and compared to control: 2% (w/w) and 6% (w/ w), to provide high levels of algae-bioactives. The cookies sensory and physical properties were evaluated during eight weeks showing high color and texture stability. Cookies prepared with A. platensis and C. vulgaris presented significantly (p < 0.05) higher protein content compared to the control, and by sensory analysis A. platensis cookies were preferred. Besides, A. platensis also provided a structuring effect in terms of cookies texture. All microalgae-based cookies showed significantly higher (p < 0.05) total phenolic content and in vitro antioxidant capacity compared to the control. No significant difference (p < 0.05) in in vitro digestibility between microalgae cookies and the control was foundinfo:eu-repo/semantics/publishedVersio

Effect of dietary honey on intestinal microflora and toxicity of mycotoxins in mice

BACKGROUND: Bee honey is a functional food which has a unique composition, antimicrobial properties and bifidogenic effect. In order to assess whether honey can inhibit the toxic effect of mycotoxins, the present study was undertaken. METHODS: Production of biomass and toxins by Aspergillus parasiticus and Aspergillus ochraceus were followed in media without and with honey. Although aflatoxins and ochratoxin A. were administrated to male Swiss albino mice up to 1 μg and 10 ng/kg body weight/day respectively. The experimental animals were fed diets without our with 10% honey for two months. The changes in colonic probiotic bacteria, determintal colon enzyme glucuronidases, and genotoxicity were followed. RESULTS: Addition of 32% in its media increased the biomass of A parasiticus, while the biomass of A. ochraceus decreased and Ochratoxin A. was not produced. When the honey was added at the ratio of 32 and 48% in the medium. No relationship was found between mycelium weight and production of mycotoxins. Oral administration of aflatoxins (mixture of B(1), B(2), G(1) and G(2)) and Ochratoxin A. induced structural and numerical chromosomal aberrations in bone marrow and germ cells of male mice, whereas, honey treatment reduced the genotoxicity of mycotoxins. Also both toxins induced histopathological changes in liver and kidney. Feeding on diet supplemented with honey improved the histopathological changes in case of aflatoxin group, but not in the case of ochratoxin A. group (except of kidney in two cases). No significant differences were found in the activity of colon β-glucuronidase between group fed diet with or without honey. On the other hand, the colon bifido bacteria and lactobacilli counts were increased markedly in group receiving diet supplemented with honey. CONCLUSION: Substituting sugars with honey in processed food can inhibit the harmful and genotoxic effects of mycotoxins, and improve the gut microflora