Anabela Raymundo

Vegetable proteins and milk puddings

Abstract In recent years, interest in animal free foods has increased tremendously due to factors like BSE crisis, rise of nutritionally dependent illnesses, like diabetes type II, cardiovascular and digestive diseases, along with ethic orientations of denying animal intakes of any kind. The use of proteins from leguminous seeds as an alternative to the animal proteins in dairy desserts was studied. Lupin, pea and soya protein isolates were used in combination with κ-carrageenan, gellan and xanthan gum, in order to obtain a synergistic effect. Milk puddings were also produced for comparison. Texture studies suggested that mixed protein–polysaccharide systems, with vegetable proteins and κ-carrageenan or gellan gum, would be good systems to develop vegetable gelled desserts. Rheological oscillatory measurements were carried out to clarify the kinetics of gelation and characterise the microstructure of the best performing products. Results from time sweep tests showed that formulations with gellan gum present an industrial advantage over formulations with κ-carrageenan, since the maturation time for gellan gels is of the order of 5–10 h compared with 4–6 days in the case of κ-carrageenan. All the mixed gels presented the typical weak gel structure; therefore, it was possible to perform steady-state measurements, which allowed the observation of a shear-thinning behaviour for all gels.

Incorporation of Chlorella vulgaris and Spirulina maxima biomass in pasta products. Part 1: Preparation and evaluation†

BACKGROUND Microalgae are able to enhance the nutritional content of conventional foods and hence to positively affect human health, due to their original chemical composition. The aim of the present study was to prepare fresh spaghetti enriched with different amounts of microalgae biomass (Chlorella vulgaris and Spirulina maxima) and to compare the quality parameters (optimal cooking time, cooking losses, swelling index and water absorption), chemical composition, instrumental texture and colour of the raw and cooked pasta enriched with microalgae biomass with standard semolina spaghetti. RESULTS The incorporation of microalgae results in an increase of quality parameters when compared to the control sample. The colour of microalgae pastas remained relatively stable after cooking. The addition of microalgae resulted in an increase in the raw pasta firmness when compared to the control sample. Of all the microalgae studied, an increase in the biomass concentration (0.5-2.0%) resulted in a general tendency of an increase in the pasta firmness. Sensory analysis revealed that microalgae pastas had higher acceptance scores by the panellists than the control pasta. CONCLUSION Microalgae pastas presented very appellative colours, such as orange and green, similar to pastas produced with vegetables, with nutritional advantages, showing energetic values similar to commercial pastas. The use of microalgae biomass can enhance the nutritional and sensorial quality of pasta, without affecting its cooking and textural properties.

Effect of thermal denaturation of lupin protein on its emulsifying properties

The effect of the protein-thermal treatment on the rheological behaviour, texture, surface hydrophobicity, droplet size distribution and colour of oil-in-water emulsions stabilised by a vegetable protein isolated from Lupinus albus seeds was studied. Protein isolates dispersions were treated at different temperatures, 50-90°C, whilst the thermal treatment time was varied between 10 and 40 min. The study was carried out according to an experimental design based on the response surface methodology (RSM). It was found that protein thermal treatment increases the values of the rheological and textural parameters and the protein surface hydrophobicity, and decreases the Sauter diameter of oil droplets.

Method to Evaluate Foaming Performance

in this work, a methodology to evaluate foaming capacity and stability is proposed. With this method the foam volume decay is followed and the overrun [(foam volume -solution volume)isolution volume] plotted against time. The integral of overrun decay for a jixed period was tried out as a single parameter to describe foam properties, i.e. foaming capacity and foam stability. It was concluded that using this single parameter; the foaming stability index (ES.I.),, the application of statistical experimental design methodology to optimise foaming becomes straightforward. As an example of an application of this method, the denaturation extent of the protein was optimised to improve the foaming properties of Lupin protein isolate. 0 1998 Elsevier Science Limited. A 11 rights reserved

Effect of sucrose, stevia and xylitol on rheological properties of gels from blends of chestnut and rice flours.

The development of high quality gluten-free products requires the understanding of the phenomena that dictate the ingredient interactions commonly used in foodstuff. In this work, the main objective was to develop alternative gluten-free gelled desserts from blends of chestnut flour (Cf) and whole (Rw), Agulha (Ra) or Carolino (Rc) rice flours. The impact of sucrose, stevia and xylitol on textural, rheological and structural properties of selected gels was investigated. Texture results indicated that studied gels in the presence of sucrose and xylitol decreased significantly the firmness. Rheological outcomes showed that the temperature ramps on heating of Cf/Rw gels were similar to those obtained for Cf/Ra, whereas Cf/Rc gels presented a particular pattern. The presence of sucrose resulted in a significant decrease in the values of storage and loss moduli. Confocal microscopic images showed that the sugar addition leads to a less aggregated structure with fracture lines well marked.

Spirulina maxima and Diacronema vlkianum microalgae in vegetable gelled desserts

Purpose – The purpose of this paper is to develop microalgae vegetable‐based gelled desserts (similar to “dairy desserts”) prepared with pea protein isolate, Spirulina maxima and Diacronema vlkianum biomass, rich in essential fatty acids (omega‐3 polyunsaturated fatty acids (PUFA)). The effect of microalgae concentration and gelling temperature on the colour, texture and fatty acid profile of the gels was investigated.Design/methodology/approach – Pea protein isolate (4 per cent), κ‐carrageenan (0.15 per cent) and starch (2.5 per cent) were used to produce a gelled dessert that was further enriched with microalgal biomass (0.1‐1.0 per cent). The gels were prepared using different temperatures, ranging from 75 to 90 ○C. Colour, total pigments (carotenoids), texture and fatty acid profile of the gels were evaluated.Findings – The addition of Diacronema and Spirulina microalgal biomass to vegetable gelled deserts, results in a novel alternative food product, with PUFAs (e.g. EPA, DHA and GLA), with favoura...

Development and rheological properties of ecological emulsions formulated with a biosolvent and two microbial polysaccharides

The influence of gum concentration and rhamsan/welan gum ratio on rheological properties, droplet size distribution and physical stability of eco-friendly O/W emulsions stabilized by an ecological surfactant were studied in the present work. The emulsions were prepared with 30wt% α-pinene, a terpenic solvent and an ecological alternative for current volatile organic compounds. Rheological properties of emulsions showed an important dependence on the two studied variables. Flow curves were fitted to the Cross model and no synergistic effect between rhamsan and welan gums was demonstrated. Emulsions with submicron mean diameters were obtained regardless of the gum concentration or the rhamsan/welan ratio used. Multiple light scattering illustrated that creaming was practically eliminated by the incorporation of polysaccharides. The use of rhamsan and welan gums as stabilizers lead to apparent enhancements in emulsion rheology and physical stability.

Characterization of a Novel Intrinsic Luminescent Room‐Temperature Ionic Liquid Based on [P6,6,6,14][ANS]

Intrinsically luminescent room-temperature ionic liquids (RTILs) can be prepared by combining a luminescent anion (more common) or cation with appropriate counter ions, rendering new luminescent soft materials. These RTILs are still new, and many of their photochemical properties are not well known. A novel intrinsic luminescent RTIL based on the 8-anilinonaphthalene-1-sulfonate ([ANS]) anion combined with the trihexyltetradecylphosphonium ([P6,6,6,14 ]) cation was prepared and characterized by spectroscopic techniques. Detailed photophysical studies highlight the influence of the ionic liquid environment on the ANS fluorescence, which together with rheological and (1) H NMR experiments illustrate the effects of both the viscosity and electrostatic interactions between the ions. This material is liquid at room temperature and possesses a glass transition temperature (Tg ) of 230.4 K. The fluorescence is not highly sensitive to factors such as temperature, but owing to its high viscosity, dynamic Stokes shift measurements reveal very slow components for the IL relaxation.

Influence of Na+, K+ and Ca2+ on mechanical and structural properties of gels from chestnut and rice flours

The addition of salts to foodstuffs to improve the mechanical characteristics and thereby increasing sample strength has been widely studied in gels of model systems, however has been investigated to a lesser extent in complex systems, such as gluten-free flour gels. The objective of this study was to evaluate the impact of cation concentration and ion valence of chloride salts (NaCl, KCl or CaCl2, 0-2%, w/w) on textural, rheological and microstructural properties of selected gluten-free flour gels from blends of chestnut flour and whole, Agulha or Carolino rice flours. Firmness increased in the presence of CaCl2. Storage and loss moduli increased slightly with the monovalent salts concentration, whereas a more pronounced rise was observed with the divalent salt addition. It was found that K(+) was more effective in modifying the rheology of studied gels than Na(+). Confocal microscopic images of gels revealed a microstructure consistent with the observed mechanical properties.

EFFECT OF pH AND NaCI ON RHEOLOGICAL AND TEXTURAL PROPERTIES OF LUPIN PROTEIN EMULSIONS

ABSTRACT The effect of pH on textural and rheological properties of lupin protein o/w emulsions at various protein contents (2, 3, 4, 5 and 6% wt) was studied. Five emulsions with different pH values ranging from 3 to 8 were prepared at each protein content. The NaCI concentration effect was also investigated on 4.5% wt protein emulsions with salt contents ranging from 0.3 to 5% wt. In both cases, the sunflower oil content was 65% wt. From the results of this work it was observed that for all protein concentrations tested, the textural and rheological properties reach a minimum at a pH value around the protein isoeletric point (pH ca. 4.5), and the oil droplet size given by d 32, shows a maximum at this pH value, indicating low emulsion stability. In the study of the effect of salt, at pH 2.5 the addition of salt reduces emulsion stability, at pH 4.5 the emulsion physical properties are independent of salt concentration and at pH 6.5 the salt addition enhances structure, texture and stability of the emulsions.