Physicochemical properties of konjac glucomannan/alginate films enriched with sugarcane vinasse intended for mulching applications.

Biodegradable films are a promising strategy to reduce the environmental impact caused by conventional plastics commonly used in agriculture. This study focused on the production and characterization of Konjac glucomannan (KGM) and alginate (ALG) based films enriched with sugarcane vinasse (VIN), a nutrient-rich wastewater generated in large volumes by the sugar-ethanol producing industries. ALG, KGM and ALG/KGM blended (50:50) films were produced by casting and treated with calcium ions (Ca2+) (ALG films) and a combination of Ca2+, alkali, and ethanol (KGM and ALG/KGM films). Vinasse addition tended to reduce transparency and water resistance of the films and had less effect on their mechanical properties. Crosslinking of ALG films resulted in enhanced mechanical properties and reduced moisture content, water solubility, swelling, water vapor permeability, and flexibility. KGM films were less impacted by crosslinking/deacetylation but showed improved water resistance while maintain a high degree of swelling (290% and 185% for KGM and KGM/VIN films respectively). Blended films exhibited characteristic properties of the two biopolymers and adequate compatibility indicated by Fourier transform infrared spectroscopy (FTIR) and morphologies. Vinasse-added ALG/KGM films represent a novel nutrient-enriched, bio-based material for agricultural applications and could help to face the environmental challenges imposed by vinasse disposal.

Sugarcane vinasse and microalgal biomass in the production of pectin particles as an alternative soil fertilizer.

High methoxyl pectin was used as biopolymeric matrix to produce a novel slow release soil fertilizer added with sugarcane vinasse and lipid extracted microalgal (Desmodesmus subspicatus) biomass residue (LMBR). Vinasse acted as the biopolymer solvent, providing greater stability to pectin gel, and as a source of nitrogen (N), potassium (K), calcium (Ca) and magnesium (Mg). LMBR (0.5%) was considered a complementary source of N and micronutrients, copper (Cu), iron (Fe) and zinc (Zn). Compared to blank pectin particles, the particles with vinasse and LMBR showed homogeneous polymer matrix, spherical shapes, higher soluble matter release and enhanced mechanical properties. Scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) analysis indicated the incorporation of microalgal biomass and nutrients from vinasse. Higher rates of biodegradation as well as larger degree of mineralization were found over a period of 36 days for vinasse and LMBR particles. These particles exhibit good perspectives as an alternative fertilizer for agriculture applications and represent an innovative solution for vinasse and LMBR final disposal.

Delaying fat bloom formation in dark chocolate by adding sorbitan monostearate or cocoa butter stearin.

Two formulations of dark chocolate were developed by adding cocoa butter stearin (CBSt) or sorbitan monostearate (SMS) and compared to a standard formulation in order to investigate fat bloom formation over time. Fat bloom was monitored by Whiteness Index (WI), melting behavior and polymorphism determinations, in bars stored during 90 days at 20 °C and under oscillating temperature between 20 and 32 °C. All samples stored at 20 °C did not develop fat bloom and the required ß(V) form was maintained. Under oscillating storage condition, samples with CBSt (6.0%, w/w) and SMS (0.15%, w/w) delayed the surface fat bloom formation by at least 45 and 15 days, respectively, compared to standard chocolate, observed visually and through WI increments. The ß(V) to ß(VI) polymorphic transition correlated well with the WI, and also with changes in DSC thermograms, confirming the higher effectiveness of specific triacylglycerol (mainly StOSt) in delaying bloom formation.

Crystallization of low saturated lipid blends of palm and canola oils with sorbitan monostearate and fully hydrogenated palm oil.

Several scientific investigations have focused on providing new strategies for supporting the development of low saturated and zero trans lipid materials, as healthier fat alternatives for food application. This work evaluated the consistency, crystallization behavior, microstructure and polymorphism of six blends composed of palm and canola oils at different concentrations (100:0, 80:20, 60:40, 40:60, 20:80 and 0:100, in w/w%) added with 5.0% of fully hydrogenated palm oil (FHPO) or with a mixture of 2.5% of FHPO and 2.5% of sorbitan monostearate (SMS). The results were compared with the non-structured blends (standard samples). Through microstructure images, the formation of a more homogeneous and denser packed crystal network was observed for samples added with both crystallization modifiers (FHPO/SMS) compared to the corresponding standard samples, after stabilization at 25 °C during 3 h. In particular, enhanced crystallization modifications were observed for the 40:60 blend, in which the crystal form ß' emerged after the addition of FHPO/SMS. Moreover, the 40:60 blend structured with FHPO/SMS showed increased consistency (from 30 to 658 gF/cm2) and induced onset crystallization in a higher temperature (from 13.1 to 23.9 °C) compared with the non-structured one, due to the specific crystallization effects provided by both added structurants.

Cocoa butter symmetrical monounsaturated triacylglycerols: separation by solvent fractionation and application as crystallization modifier.

Symmetrical monounsaturated triacylglycerols-also known as SUS (saturated unsaturated saturated triacylglycerols)-are the main triacylglycerols present in cocoa butter (CB), exhibiting decisive influence in the tempering process conditions and sensorial characteristics in chocolate products. CBs with lower amounts of SUS do not crystallize adequately in chocolate processing, generating a low quality product with higher susceptibility to fat bloom formation. In this context, fractions with higher contents of SUS triacylglycerols were obtained by solvent fractionation of cocoa butter, under four operating conditions varying crystallization temperatures (17, 18, 20 and 22 °C) and sample/acetone solvent ratios (1:7 and 1:5, in w/v). After solvent evaporation, CB fractions were evaluated in terms of triacylglycerol profile, solid fat content and melting point. The solvent fractionation performed at 17 °C with a 1:7 ratio of cocoa butter:acetone favored the separation of a higher concentrated SUS stearin (denominated as S17) with 7.1% increment in SUS triacylglycerols, mainly StOSt-1-stearyl-2-oleoyl-stearin (26.9%) and POSt-1-palmitoyl-2-oleoyl-stearin (45.0%). Additionally, S17 was added to pure cocoa butter at three different proportions of CB:S17 (95:5, 90:10 and 80:20, in w/w) and the blend was evaluated by isothermal crystallization (at 17.5 °C) and consistency (at 10, 15 and 20 °C). Compared to the pure cocoa butter, at 10 °C, the blend with 20% stearin (80:20) showed an increment of 67% in the consistency and considerable higher crystallization rates at 17.5 °C were found, confirming the potential contribution of the SUS triacylglycerols as crystallization modifiers of CB.

Crystallization modifiers in lipid systems.

Crystallization of fats is a determinant physical event affecting the structure and properties of fat-based products. The stability of these processed foods is regulated by changes in the physical state of fats and alterations in their crystallization behavior. Problems like polymorphic transitions, oil migration, fat bloom development, slow crystallization and formation of crystalline aggregates stand out. The change of the crystallization behavior of lipid systems has been a strategic issue for the processing of foods, aiming at taylor made products, reducing costs, improving quality, and increasing the applicability and stability of different industrial fats. In this connection, advances in understanding the complex mechanisms that govern fat crystallization led to the development of strategies in order to modulate the conventional processes of fat structuration, based on the use of crystallization modifiers. Different components have been evaluated, such as specific triacyglycerols, partial glycerides (monoacylglycerols and diacylglycerols), free fatty acids, phospholipids and emulsifiers. The knowledge and expertise on the influence of these specific additives or minor lipids on the crystallization behavior of fat systems represents a focus of current interest for the industrial processing of oils and fats. This article presents a comprehensive review on the use of crystallization modifiers in lipid systems, especially for palm oil, cocoa butter and general purpose fats, highlighting: i) the removal, addition or fractionation of minor lipids in fat bases; ii) the use of nucleating agents to modify the crystallization process; iii) control of crystallization in lipid bases by using emulsifiers. The addition of these components into lipid systems is discussed in relation to the phenomena of nucleation, crystal growth, morphology, thermal behavior and polymorphism, with the intention of providing the reader with a complete panorama of the associated mechanisms with crystallization of fats and oils.