Structural and mechanical properties of organogels: Role of oil and gelator molecular structure

Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.foodres.2017.03.021.This work aims at evaluating the influence of oil and gelator structure on organogels' properties through rheological measurements, polarized microscopy and small-angle X-ray scattering (SAXS). Four different food-grade gelators (glyceryl tristearate GT; sorbitan tristearate ST; sorbitan monostearate SM and glyceryl monostearate - GM) were tested in medium-chain triglyceride and high oleic sunflower (MCT and LCT, respectively) oil phases. Organogels were prepared by mixing the oil phase and gelator at different concentrations (5, 10, 15, 20 and 25%) at 80 °C during 30 min. All organogels presented birefringence confirming the formation of a crystalline structure that changed with the increase of the gelator concentration. Through the evaluation of SAXS peaks it has been confirmed that all structures were organized as lamellas but with different d-spacing values. These particularities at micro- and nanoscale level lead to differences in rheological properties of organogels. Results showed that the oil type (i.e. medium- and long-chain triglyceride) and hydrophilic head of gelators (i.e. sorbitan versus glyceryl) exert influence on the organogels physical properties, but the presence of monostearate leads to the formation of stronger organogels. Moreover, gels produced with LCT were stronger and gelled at lower organogelator concentration than MCT.The authors thank the FCT Strategic Project of UID/BIO/04469/2013 unit, the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and the project “BioInd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes”, REF. NORTE-07- 0124-FEDER-000028 co-funded by the Programa Operacional Regional do Norte (ON.2 – O Novo Norte), QREN, FEDER. The financial support of CAPES/FCT Project “Nanotechnological systems based in biocompatible ingredients: characterization, controlled release and in vitro digestion” (CAPES/FCT n° 348/13) and CNPq (Universal 479459/2012-6) are gratefully acknowledged. The authors also thank the Brazilian Synchrotron Light Laboratory (LNLS) for the opportunity to carry out SAXS measurements.info:eu-repo/semantics/publishedVersio

Influence of organic acids on surfactant self-assemblies in surfactant/oil/water systems

The cosurfactant effect of short-chain organic acids (acetic and propionic acids) and their behavior in relation to the oil prevailing unsaturation (HOSO or sunflower oil) was evaluated from SAXS and rheological measurements in systems formed by water, oil, Tween80 and the organic acid. Self-assemble of the surfactants was influenced by the structure and ratio of the components, which formed different structures (microemulsions and liquid crystal) with different rheological behaviors. The water content exerted influence on the organization of the surfactant moieties and on the dissociation of the cosurfactant, modifying its partition to the water phase. Systems with acetic acid formed more rigid structures with higher viscosity, shear-thinning behavior and bigger distances between the structures due to the tendency of this acid to migrate to water phase. On the other hand, propionic acid was less susceptible to dissociation, being in its neutral form, which makes it able to remain at the interface and solubilize higher oil content. As a result, structures were softer with lower viscosity and slightly smaller distances between them. The interaction between oil and cosurfactant exerted influence on the colloidal properties that reflected on bulky properties. In general, the more hydrophobic oil (sunflower oil) facilitated the partition of the acetic acid to the water, giving to this structure greater distance, as compared to HOSO + acetic acid. Thus, small differences in the structure of the components can influence the interaction between them, changing the partition of the components and the surfactant behavior.459290297CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informaçãoSem informação2009/54137-

DYNAMIC AND STEADY-SHEAR RHEOLOGICAL PROPERTIES OF XANTHAN AND GUAR GUMS DISPERSED IN YELLOW PASSION FRUIT PULP (Passiflora edulis f. flavicarpa)

Yellow passion fruit pulp is unstable, presenting phase separation that can be avoided by the addition of hydrocolloids. For this purpose, xanthan and guar gum [0.3, 0.7 and 1.0% (w/w)] were added to yellow passion fruit pulp and the changes in the dynamic and steady-shear rheological behavior evaluated. Xanthan dispersions showed a more pronounced pseudoplasticity and the presence of yield stress, which was not observed in the guar gum dispersions. Cross model fitting to flow curves showed that the xanthan suspensions also had higher zero shear viscosity than the guar suspensions, and, for both gums, an increase in temperature led to lower values for this parameter. The gums showed different behavior as a function of temperature in the range of 5-35 degrees C. The activation energy of the apparent viscosity was dependent on the shear rate and gum concentration for guar, whereas for xanthan these values only varied with the concentration. The mechanical spectra were well described by the generalized Maxwell model and the xanthan dispersions showed a more elastic character than the guar dispersions, with higher values for the relaxation time. Xanthan was characterized as a weak gel, while guar presented a concentrated solution behavior. The simultaneous evaluation of temperature and concentration showed a stronger influence of the polysaccharide concentration on the apparent viscosity and the G` and G `` moduli than the variation in temperature.28348349

Emergent food proteins Towards sustainability, health and innovation

There is an increasing demand for alternative and sustainable protein sources, such as vegetables, insects and microorganisms, that can meet the nutritional and sensory pleasantness needs of consumers. This emergent interest for novel protein sources, allied with green and cost-effective processing technologies, such as high hydrostatic pressure, ohmic heating and pulsed electric fields, can be used as strategies to improve the consumption of proteins from sustainable sources without compromising food security. In addition to their nutritional value, these novel proteins present several technological-functional properties that can be used to create various protein systems in different scales (i.e., macro, micro and nano scale), which can be tailored for a specific application in innovative food products. However, in order for these novel protein sources to be broadly used in future food products, their fate in the human gastrointestinal tract (e.g., digestion and bioavailability) must be assessed, as well as their safety for consumers must be clearly demonstrated. In particular, these proteins may become novel allergens triggering adverse reactions and, therefore, a comprehensive allergenicity risk assessment is needed. This review presents an overview of the most promising alternative protein sources, their application in the production of innovative food systems, as well as their potential effects on human health. In addition, new insights on sustainable processing strategies are given.This work was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic fundingof UID/ BIO/04469/2019 and UID/Multi/50016/2019 units and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte 2020-Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Addition of green banana flour to instant noodles: rheological and technological properties Adição de farinha de banana verde em macarrão instantâneo: propriedades reológicas e tecnológicas

Nowadays, there is considerable concern about the consumption of high fat and low fiber foods. The objective was to develop instant noodles (IN) with functional properties by adding 10% green banana flour (GBF), and determine the effect of this on the dough rheological properties. Noodles were obtained through sheeting, steaming and frying process. The IN were characterized for their moisture, fat, resistant starch (RS), texture and color. The proximate composition showed that GBF was rich in ash (3.16%), fiber (8.88%) and RS (45.70%), being an attractive raw material for the production of functional IN. When 10% GBF was added, rheological properties of dough changed because of dilution of gluten, making it weaker, but with enough extensibility and elasticity for functional IN production. The addition of 10% GBF significantly reduced the oil content in all the frying times, when compared to the control noodles, increasing also RS content. Ban10 noodles showed a lower L* value (78.12), indicating a darker color than the control noodles (92.36). In analyzing the firmness of Ban10 noodles, a decrease was observed due to dilution of gluten. However, Ban10 noodles showed a better nutritional profile due to the increase in ash and dietary fiber contents. In conclusion it can be affirmed that Ban10 noodles can be considered as functional IN, due to the presence of fiber (5.79%) and RS (3.98%) contents in the final product.<br>Atualmente, existe uma preocupação com relação ao consumo de alimentos com alto teor de gordura e baixo em fibras. Neste trabalho, objetivou-se desenvolver macarrão instantâneo com propriedades funcionais através da adição de 10% de farinha de banana verde (FBV) e determinar os efeitos nas propriedades reológicas da massa. Os macarrões instantâneos foram obtidos por processos de laminação, cozimento a vapor e fritura. Os macarrões foram caracterizados quanto à umidade, gordura, amido resistente, textura e cor. A composição centesimal mostrou que a FBV contém alto teor de cinzas (3,16%), fibras (8,88%) e amido resistente (45,70%), sendo uma matéria-prima interessante na produção de macarrão instantâneo funcional. Quando adicionado 10% de FBV à farinha de trigo as propriedades reológicas da massa foram alteradas, em razão da diluição do glúten, tornando-o mais fraco, mas com extensibilidade e elasticidade suficiente para a produção de macarrão instantâneo funcional. A adição de FBV reduziu significativamente o teor de gordura em todos os tempos de fritura e aumentou o teor de amido resistente, quando comparado ao macarrão instantâneo controle. Os macarrões Ban10 apresentaram um menor valor no parâmetro L* (78,12), indicando uma coloração mais escura do que o controle (92,36). A adição de FBV diminuiu a firmeza dos macarrões, em decorrência da diluição do glúten. No entanto, os macarrões Ban10 apresentaram um melhor perfil nutricional, pelo aumento no teor de cinzas e fibra alimentar total. Em conclusão, pode ser afirmado que os macarrões Ban10 podem ser considerados funcionais, em razão do teor alto de fibra (5,79%) e de amido resistente (3,98%)