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Campos D.C.,Technology and Processes Unit | Campos D.C.,University of the Frontier | Acevedo F.,Technology and Processes Unit | Morales E.,Technology and Processes Unit | And 6 more authors.
World Journal of Microbiology and Biotechnology | Year: 2014

Plant growth promoting bacteria and nitrogen-fixing bacteria (NFB) used for crop inoculation have important biotechnological potential as a sustainable fertilization tool. However, the main limitation of this technology is the low inoculum survival rate under field conditions. Microencapsulation of bacterial cells in polymer matrices provides a controlled release and greater protection against environmental conditions. In this context, the aim of this study was to isolate and characterize putative NFB associated with lupin nodules and to evaluate their microencapsulation by spray drying. For this purpose, 21 putative NFB were isolated from lupin nodules and characterized (16S rRNA genes). Microencapsulation of bacterial cells by spray drying was studied using a mixture of sodium alginate:maltodextrin at different ratios (0:15, 1:14, 2:13) and concentrations (15 and 30 % solids) as the wall material. The microcapsules were observed under scanning electron microscopy to verify their suitable morphology. Results showed the association between lupin nodules of diverse known NFB and nodule-forming bacteria belonging to Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Bacteroidetes. In microencapsulation assays, the 1:14 ratio of sodium alginate:maltodextrin (15 % solids) showed the highest cell survival rate (79 %), with a microcapsule yield of 27 % and spherical microcapsules of 5-50 μm in diameter. In conclusion, diverse putative NFB genera and nodule-forming bacteria are associated with the nodules of lupine plants grown in soils in southern Chile, and their microencapsulation by spray drying using sodium alginate:maltodextrin represents a scalable process to generate a biofertilizer as an alternative to traditional nitrogen fertilization. © 2014 Springer Science+Business Media Dordrecht.

Uquiche E.,University of the Frontier | Uquiche E.,Technology and Processes Unit | Fica X.,University of the Frontier | Salazar K.,University of the Frontier | Del Valle J.M.,University of Santiago de Chile
JAOCS, Journal of the American Oil Chemists' Society | Year: 2012

This work explored the possibility of using supercritical carbon dioxide (SC-CO 2) to achieve fractionation of pre-pressed rapeseed (Brassica napus) cake oil at 30-50 MPa, at 40 or 80 °C, and increase the concentration of minor lipids (sterols, tocopherols, carotenoids) in the oil. Minor lipids are partially responsible for desirable antioxidant effects that protect against degradation and impart functional value to the oil. The weight and concentration of minor lipids in oil fractions collected during the first 60 min were analyzed. Cumulative oil yield increased with pressure, and with temperature at ≥40 MPa, but was lower at 80 °C than at 40 °C when working at pressure ≤35 MPa. Differences in solubility between the oil and minor lipids explained fractionation effects that were small for tocopherols. Unlike tocopherols, which are more soluble in SC-CO 2 than the oil, sterols and carotenoids are less soluble than the oil, and their concentration increased in the later stages of extraction, particularly at ≥40 MPa, when there was not enough oil to saturate the CO 2 phase. Because of the fractionating effects on rape-seed oil composition, there was an increase in the antioxidant activity of the oil in the second half as compared to the first half of the extraction. Consequently, this study suggests that SC-CO 2 extraction could be used to isolate vegetable oil fractions with increased functional value. © 2011 Springer-Verlag.

Burgos-Diaz C.,Technology and Processes Unit | Rubilar M.,University of the Frontier | Morales E.,Technology and Processes Unit | Medina C.,University of the Frontier | And 3 more authors.
European Journal of Lipid Science and Technology | Year: 2016

The use of proteins, polysaccharides, and their mixtures as bioemulsifiers is becoming increasingly important due to their high versatility and environmental acceptability. In this study, three different fractions mainly composed of protein and polysaccharides, extracted from linseed were evaluated as bioemulsifiers. The three fractions showed the same functional groups, and the amino acid profile revealed the presence of apolar amino acids which are important for forming emulsions. All negatively charged fractions were affected at pH values below 6 and above 100mM NaCl, confirming their ionic character. Fraction 3 formed oil-in-water emulsion (O/W) and its estimated hydrophilic-lipophilic balance (HLB) value was 10-13. A phase diagram was used to produce a long-term stable O/W emulsion using Fraction 3 as a bioemulsifier. The emulsion containing linseed oil Fraction 3 and water of 5:5:90% w/w exhibited 100% stability under a wide pH range (5-11), ionic strengths (0-500mM NaCl), and temperatures (4-70°C). Based on these results, Fraction 3, composed of 47.20% w/w protein and 37.88% w/w polysaccharide from linseed, can be considered a potential natural emulsifier for improving stability of O/W emulsions in the face of environmental stresses. Practical applications: The increasing customer demand for natural over synthetic ingredients and the rapid growth of functional foods requiring "green" additives represents an opportunity for bioemulsifiers extracted from natural resources. Linseed and the by-products after oil extraction have great potential as a source of ingredients and bioactive molecules for food applications. In this work, the capability of protein/polysaccharide fractions from linseed as bioemulsifiers to form highly stable O/W emulsions containing omega-3 rich oil was demonstrated. The designed emulsion proved to be stable at acidic pH and salt concentrations found in many food products. Moreover, thermal stability exhibited by this emulsion could also be an important characteristic for its use in food products. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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