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Burgos-Diaz C.,Agriaquaculture Nutritional Genomic Center | Gallardo M.,niversity La FronteraTemucoChile | Morales E.,Agriaquaculture Nutritional Genomic Center | Piornos J.A.,Agriaquaculture Nutritional Genomic Center | Rubilar M.,Biorenuniversidad Of La Fronteratemucochile
European Journal of Lipid Science and Technology | Year: 2015

The formation of multilayered interfaces around oil droplets in oil-in-water (O/W) emulsions provides a novel means of improving the quality and stability of many food products. In this work, a system of O/W emulsions containing lipid droplets stabilized by different ionic biopolymers was developed, and their stability under different environmental stresses was evaluated. The protein isolate from a new lupin variety (AluProt-CGNA) and two polysaccharides-chitosan and xanthan gum-were utilized. AluProt-CGNA protein-stabilized emulsions were unstable to aggregation at pH values around their isoelectric point (pI 4.6) and to all the temperatures and salt concentrations evaluated in this study. However, in the presence of chitosan (0.06 wt%), the droplets showed good stability to aggregation from pH 3 to 6, at 30-90°C and at ≤100mM NaCl. Adding xanthan gum (0.1 wt%) to the system improved emulsion stability from pH 4 to 7, where no phase separation was observed. This study showed that the stability of O/W emulsions containing protein (AluProt-CGNA)-coated lipid droplets under environmental stresses can be improved by adding certain concentrations of chitosan and xanthan gum. These findings have important implications for the design of encapsulation and delivery systems for lipophilic compounds in the food industries. Practical applications: The development of multilayer emulsions can be extremely useful to the encapsulation of lipophilic bioactive molecules for food applications, such as polyunsaturated fatty acids (PUFAs), flavors, vitamins, etc. Moreover, this technique provides a system for the creation of O/W emulsions with improved stability to environmental stresses, protection of oil phase, and controlled and triggered release of microencapsulated compounds. In this work, the design of stable O/W emulsions containing PUFAs rich oil droplets surrounded by multiple layer interfacial membranes from food grade ingredients, such as lupin proteins (AluProt-CGNA), chitosan, and xanthan gum membranes; has been performed. The designed emulsion proved to be stable under different environmental stresses found in many food products. Moreover, thermal stability exhibited by these emulsions could also be an important characteristic for its use in food products. The diagram shows the formation of multilayer emulsions. The diagram shows the formation of multilayer emulsions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Source


Shene C.,Biorenuniversidad Of La Fronteratemucochile | Monsalve M.T.,niversity La FronteraTemucoChile | Vergara D.,niversity La FronteraTemucoChile | Lienqueo M.E.,University of ChileSantiagoChile | Rubilar M.,niversity La FronteraTemucoChile
European Journal of Lipid Science and Technology | Year: 2015

Nannochloropsis is a genus of unicellular eukaryotes known primarily from the marine environment whose members are potential sources of lipids and long-chain polyunsaturated fatty acids; for the extraction of these and other valuable cell components, cell disruption is needed. High pressure homogenization (HPH) would be particularly suitable for microalgae with a recalcitrant cell wall such as Nannochloropsis. HPH conditions should be determined based on both the target cell component and properties of the cell suspension that in some cases are dependent on the age of the culture. The yields of soluble protein and total sugars from N. oculata ranged from 22.7 to 50.4mg/g and from 55.0 to 62.5mg/g, respectively, depending on HPH conditions (loading pressure and number of passes). The yield of the lipids extracted with the method of Bligh and Dyer was not affected by HPH conditions whereas lipids extracted with Soxhlet method ranged between 8.2 and 16.2%. Main fatty acids in the lipids extracted with the method of Bligh and Dyer and total lipids were palmitic acid (17.2±0.1-23.0±0.2%), palmitoleic acid (22.9±0.3-19.1±0.9%), and eicosapentaenoic acid (20.6±0.3-29.2±0.3%). HPH of N. oculata cells promoted a different effect on particle size distribution (PSD) depending on the age of the culture. HPH reduced cell aggregation observed in the 10 day cell suspension, whereas it promoted aggregation of the 30 day cell suspension. Practical applications: The feasibility of producing a wide range of products from microalgae is determined by the culture conditions and the conditions of the stages in the downstream processing. Because main microalgae components are intracellular, a scalable cell disruption operation such as HPH is required. Cell disruption degree is determined not only by the equipment design and its operational conditions but also by the cell suspension properties. The results allowed us to conclude that a different combination loading pressure/number of passes in HPH maximizes the recovery of hydrosoluble compounds (proteins and sugars) and lipids in N. oculata. Besides, since the PSD of the microalgae suspension is a function of culture age, this variable could affect process productivity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Burgos-Diaz C.,Technology and Processes UnitAgriaquaculture Nutritional Genomic Center | Rubilar M.,Biorenuniversidad Of La Fronteratemucochile | Morales E.,Technology and Processes UnitAgriaquaculture Nutritional Genomic Center | Medina C.,niversity La FronteraTemucoChile | And 2 more authors.
European Journal of Lipid Science and Technology | Year: 2015

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. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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