A new way of valorizing biomaterials: the use of sunflower protein for 1 a-tocopherol microencapsulation

Biopolymer based microparticles were efficiently prepared from sunflower protein (SP) wall material and a-tocopherol (T) active core using a spray-drying technique. Protein enzymatic hydrolysis and/or N-acylation were carried out to make some structural modifications to the vegetable protein. Native and hydrolyzed SP were characterized by Asymmetrical Flow Field-Flow Fractionation (AsFlFFF). Results of AsFlFFF confirmed that size of proteinic macromolecules was influenced by degree of hydrolysis. The effect of protein modifications and the influence of wall/core ratio on both emulsions and microparticle properties were evaluated. Concerning emulsion properties, enzymatic hydrolysis involved a decrease in viscosity, whereas acylation did not significantly affect emulsion droplet size and viscosity. Microparticles obtained with hydrolyzed SP wall material showed lower retention efficiency (RE) than native SP microparticles (62-80% and 93% respectively). Conversely, acylation of both hydrolyzed SP and native SP allowed a higher RE to be reached (up to 100%). Increasing T concentration increased emulsion viscosity, emulsion droplet size, microparticle size, and enhanced RE. These results demonstrated the feasibility of high loaded (up to 79.2% T) microparticles

Non-destructive determination of fat content in green hams using ultrasound and X-rays

[EN] This work addresses the use of ultrasound (US) and medical dual energy X-ray absorptiometry methods to predict the fat content in green pork hams. Ultrasonic velocity (õ) and X-ray absorption were measured in 78 green hams. An increase in the fat content involved an increase in õ and a decrease in the X-ray attenuationmeasured at 2 °C.Models developed to predict the fat content fromthe ultrasonic velocity or X-ray parameters provided errors of 2.97% and 4.65%, respectively. The combination of both US and X-ray technologies did not improve prediction accuracy. These models allowed green hams to be classified into three levels of fatness, with 88.5% and 65.4% of the hams correctly classified when using models based on ultrasonic and X-ray parameters, respectively. Therefore, US and X-rays emerge as useful quality control technologies with which to estimate the fat content in green pork hamsThis work was supported by the spanish Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA) (contracts n. RTA2010-00029-CO4-01/02) and by Universitat Politecnica de Valencia (UPV) through the FPI grant given to Marta de Prados (SP-1.2011-S1-2757).Prados Pedraza, MD.; Fulladosa, E.; Gou, P.; Muñoz, I.; García Pérez, JV.; Benedito Fort, JJ. (2015). Non-destructive determination of fat content in green hams using ultrasound and X-rays. Meat Science. 104:37-43. https://doi.org/10.1016/j.meatsci.2015.01.015S374310

Engineering of acidic O/W emulsions with pectin

Pectins with distinct molecular design were isolated by aqueous extraction at pH 2.0 or 6.0 and were examined in terms of their formation and stabilisation capacity of model n-alkane–in–water emulsions at acidic pH (pH 2.0). The properties and stability of the resulting emulsions were examined by means of droplet size distribution analysis, Lifshitz-Slyozov-Wagner modelling, bulk rheology, interfacial composition analysis, large-amplitude oscillatory surface dilatational rheology, electrokinetic analysis and fluorescence microscopy. Both pectin preparations were able to emulsify alkanes in water but exhibited distinct ageing characteristics. Emulsions prepared using pectin isolated at pH 6.0 were remarkably stable with respect to droplet growth after thirty days of ageing, while those prepared with pectin isolated at pH 2.0 destabilised rapidly. Examination of chemical composition of interfacial layers indicated multi-layered adsorption of pectins at the oil-water interface. The higher long-term stability of emulsions prepared with pectin isolated at high pH is attributed to mechanically stronger interfaces, the highly branched nature and the low hydrodynamic volume of the chains that result in effective steric stabilisation whereas acetyl and methyl contents do not contribute to the long-term stability. The present work shows that it is possible by tailoring the fine structure of pectin to engineer emulsions that operate in acidic environments

Characterization of food emulsions using ultrasonic spectroscopy

Analytical instruments based on ultrasonic spectroscopy have been recently developed to measure the size distribution and droplet concentration of emulsions. Nevertheless, there are a number of problems that currently limit the practical application of these instruments to food emulsions: (i) ultrasonic measurements often have to be made at different temperatures; (ii) many food emulsions are concentrated; and (iii) many food emulsions are flocculated. The objective of this study was therefore to investigate the influence of temperature, droplet concentration and droplet flocculation on the ultrasonic properties of emulsions, hence developing ultrasonic techniques that could be applied to food emulsions. In addition, this study also aimed at testing the efficiency of the newly developed ultrasonic scattering theories (UST) for describing ultrasonic properties of flocculated and concentrated emulsions. The influence of temperature was investigated by measuring ultrasonic velocity and attenuation coefficient of emulsions of different compositions and droplet sizes at 5 to 50°C. The ultrasonic properties of emulsions were sensitive to temperature as well as to composition and droplet size, and could be described by UST. The effect of droplet concentration (0–50 wt%) and diameter (0.2–0.58 μm) on ultrasonic properties was determined in non-flocculated oil-in-water emulsions. The traditional UST gave poor predictions of ultrasonic properties of emulsions at high droplet concentration, small droplet size and low ultrasonic frequency, while an extended UST, which incorporated the thermal overlap effects, gave much better predictions under the same conditions. The effect of flocculation on ultrasonic properties of emulsions was studied over a range of frequency (1–120 MHz) using 5% oil-in-water emulsions, flocculated by either depletion or an electrostatic mechanism. A new theory that took into account the thermal overlap effects could well explain the ultrasonic properties of flocculated emulsions. As flocculation increased, the attenuation coefficient decreased at low frequency due to the thermal overlap effect, while at high frequency the attenuation coefficient increased due to the scattering effect. The usefulness of ultrasonic techniques in characterizing actual foods was tested using salad dressing and chicken. The ultrasonic techniques could provide valuable and accurate information about the composition of these foods

Impact of weighting agents and sucrose on gravitational separation of beverage emulsions

The influence of weighting agents and sucrose on gravitational separation in 1 wt % oil-in-water emulsions was studied by measuring changes in the intensity of backscattered light from the emulsions with height. Emulsions with different droplet densities were prepared by mixing weighting agents [brominated vegetable oil (BVO), ester gum (EG), damar gum (DG), or sucrose acetate isobutyrate (SAIB)] with soybean oil prior to homogenization. Sedimentation or creaming occurred when the droplet density was greater than or lower than the aqueous phase density, respectively. The weighting agent concentrations required to match the oil and aqueous phase densities were 25 wt % BVO, 55 wt % EG, 55 wt % DG, and 45 wt % SAIB. The efficiency of droplet reduction during homogenization also depended on weighting agent type (BVO > SAIB > DG, EG) due to differences in oil phase viscosity. The influence of sucrose (0-13 wt %) on the creaming stability of 1 wt % soybean oil-in-water emulsions was also examined. Sucrose increased the aqueous phase viscosity (retarding creaming) and increased the density contrast between droplets and aqueous phase (accelerating creaming). These two effects largely canceled one another so that the creaming stability was relatively insensitive to sucrose concentration