Rheological parameters of mixed Brazilian Cerrado fruits sugar-free preserves: the effect of body agents

The aim of this study was to evaluate the effect of the bodying agents (erythritol, sorbitol, xylitol, and polydextrose) and their mixtures on the preparation of mixed Brazilian Cerrado fruit preserves (marolo, soursop, and sweet passion fruit). Mixture design was used for product optimization and the preserves were evaluated by texture profile, stress relaxation test, and uniaxial compression test. The research data were analyzed using regression equations on SAS software. The results indicated that the rheological parameters were affected by the body agents. Erythritol should not be used as an isolated component because it provoked changes in the properties of the final product (harder and brittle preserves); xylitol and sorbitol made preserves more elastic, cohesive, and more fragile; and polydextrose showed a synergistic effect with erythritol for rupture deformation and lesser effects for hardness, adhesiveness, and gumminess.

Cultivars identification of oat (Avena sativa L.) seed via multispectral imaging analysis

Cultivar identification plays an important role in ensuring the quality of oat production and the interests of producers. However, the traditional methods for discrimination of oat cultivars are generally destructive, time-consuming and complex. In this study, the feasibility of a rapid and nondestructive determination of cultivars of oat seeds was examined by using multispectral imaging combined with multivariate analysis. The principal component analysis (PCA), linear discrimination analysis (LDA) and support vector machines (SVM) were applied to classify seeds of 16 oat cultivars according to their morphological features, spectral traits or a combination thereof. The results demonstrate that clear differences among cultivars of oat seeds could be easily visualized using the multispectral imaging technique and an excellent discrimination could be achieved by combining data of the morphological and spectral features. The average classification accuracy of the testing sets was 89.69% for LDA, and 92.71% for SVM model. Therefore, the potential of a new method for rapid and nondestructive identification of oat cultivars was provided by multispectral imaging combined with multivariate analysis.

Effect of lactobionic acid on the acidification, rheological properties and aroma release of dairy gels

The food industry is investigating new technological applications of lactobionic acid (LBA). In the current work, the effect of lactobionic acid on the acidification of dairy gels (pH 5.5 and 6.2), rheological properties using a double compression test, sodium mobility using (23)Na NMR technique and aroma release using headspace GC-FID were studied. Our results showed that it is possible to use LBA as an alternative to glucono-δ-lactone (GDL) for the production of dairy gels with a controlled pH value. Small differences in the rheological properties and in the amount of aroma volatile organic compounds that were released in the vapour phase, but no significant difference in the sodium ion mobility were obtained. The gels produced with LBA were less firm and released less volatile aroma compounds than the gels produced with GDL. The gels at pH 6.2 were firmer than those at pH 5.5 and had a more organised structure around the sodium ions.

Sucrose release from polysaccharide gels

Sucrose release from polysaccharide gels has been studied extensively because it is expected to be useful in understanding flavour release from solid foods and to find a new processing method which produces more palatable and healthier foods.

Effects of Agar Gel Strength and Fat on Oral Breakdown, Volatile Release, and Sensory Perception Using in Vivo and in Vitro Systems

The density and composition of a food matrix affect the rates of oral breakdown and in-mouth flavor release as well as the overall sensory experience. Agar gels of increasing concentration (1.0, 1.7, 2.9, and 5% agarose) with and without added fat (0, 2, 5, and 10%) were spiked with seven aroma volatiles. Differences in oral processing and sensory perception were systematically measured by a trained panel using a discrete interval time intensity method. Volatile release was measured in vivo and in vitro by proton transfer reaction mass spectrometry. Greater oral processing was required as agar gel strength increased, and the intensity of flavor-related sensory attributes decreased. Volatile release was inversely related to gel strength, showing that physicochemical phenomena were the main mechanisms underlying the perceived sensory changes. Fat addition reduced the amount of oral processing and had differential effects on release, depending on the fat solubility or lipophilicity of the volatiles.

In vivo sodium release and saltiness perception in solid lipoprotein matrices. 1. Effect of composition and texture

Reducing the sodium content in foods is complex because of their multidimensional sensory characteristics and the multifunctionality of sodium chloride. The aim of this study was to elucidate how food composition may influence in-mouth sodium release and saltiness perception. Lipoprotein matrices (LPM) were produced using milk constituents and characterized by means of rheological measurements, texture, and taste sensory profiles. Texture and taste perceptions were affected differently by variations in the salt level, dry matter, and fat contents. Composition and textural changes also modified temporal sodium release and saltiness perception recorded in five subjects, but the effects varied as a function of the salt content. The water content mainly appeared to influence the amount of sodium released, whereas saltiness perception was mainly related to fat content. Elasticity, coating, and granularity were found to be correlated with temporal sodium release and/or saltiness parameters.

Concentration of soy protein isolate affects starch-based confections' texture, sensory, and storage properties

The effects of increasing soy protein isolate concentration on the physico-chemical properties of starch-based grape confectionery gels were investigated using thermal, textural, and sensory analyses. Soy protein isolate decreased hardness, cohesiveness, and gumminess, demonstrating potential as a texture modifier. Increasing soy protein concentration progressively decreased the elastic properties of the starch network demonstrated by a lower G'-G" crossover frequency. High levels of soy protein also created a more homogeneous water population, one which was lost at lower temperatures compared to standard confections. An improvement in taste and texture acceptability of the confections upon addition of soy protein isolate was found by sensory analysis. Finally, physico-chemical properties were compared up to 20 d of storage at ambient temperature. Soy-containing confections demonstrated lower gumminess and cohesiveness during the entire storage period but a significant increase in hardness after 20 d of storage.

PRACTICAL APPLICATION

Soy protein isolate imparted soft texture to starch-based confections on a concentration-dependent basis. Increasing soy protein isolate concentration decreased elastic properties of the starch network in starch confections and significantly improved flavor and texture. Gumminess and cohesiveness of soy protein isolate confection was lower during 20 d of storage.

AVALIAÇÃO DA ESTABILIDADE DE GELÉIAS LIGHT DE MORANGO E DE GOIABA

O objetivo do estudo foi a avaliação da estabilidade de geléias de morango e goiaba light, armazenadasem potes de vidro transparente de 240g. Para tanto, duas formulações foram elaboradas (1 demorango e 1 de goiaba) em planta piloto (tacho aberto a vapor)e caracterizadas quanto ao pH,sólidos solúveis, atividade de água e sinérese. Para acompanhamento da estabilidade as amostraspermaneceram armazenadas durante 180 dias em câmaras com temperaturas controladas de 10°C(controle) e 25°C (comercial), na ausência de luz, e a cada 30 dias foram realizadas análises sensoriaisdos atributos aparência geral, cor, aroma, textura e sabor, durante 180 dias, em intervalos de 30dias. Os resultados mais relevantes foram que as amostras armazenadas a 25ºC sofreram maiorqueda na qualidade, principalmente dos atributos aparência, cor e aroma. A vida-de-prateleiraestimada para as amostras de geléia light de morango e de goiaba foi de 5 a 7 meses.

COMPORTAMENTO REOLÓGICO DE SOLUÇÕES MODELO DE GELÉIAS E DOCES EM MASSA LIGHT

A mistura de géis tem atraído a atenção de um número crescente de pesquisadores devido à expectativa de maior flexibilidade em seus mecanismos e propriedades estruturais e reológicas em relação ao gel puro. O objetivo do estudo foi elaborar onze soluções modelo de doces em massa e geléias light, utilizando-se vários hidrocolóides e comparar suas características reológicas. Observou-se que a viscosidade diminuiu com o aumento da temperatura, ajustando-se ao modelo de Arrhenius. O modelo reológico que melhor se ajustou aos dados foi o de Herschel-Bulkley, com n<1, fluido pseudo-plástico. Foi avaliada a variação da viscosidade com o tempo e a maior parte das soluções modelo apresentou comportamento tixotrópico.

Influence of lambda-carrageenan on the release of systematic series of volatile flavor compounds from viscous food model systems

The effect of lambda-carrageenan addition level (0.1, 0.25, 0.4, and 0.5% w/w) and viscosity on the release of systematic series of aroma compounds (aldehydes, esters, ketones, and alcohols) was studied in thickened viscous solutions containing lambda-carrageenan and 10 wt % of sucrose. Air-liquid partition coefficients K (37 degrees C) of a total of 43 aroma compounds were determined in pure water and in the lambda-carrageenan solutions by static headspace gas chromatography. Mass transfer of the aroma compounds in water and in the thickened lambda-carrageenan solutions which had a wide viscosity range was assessed by dynamic headspace gas chromatography. K (37 degrees C) increased as the carbon chain increased within each homologous series. Esters exhibited the highest volatility, followed by aldehydes, ketones, and alcohols. Under equilibrium, no overall effect of lambda-carrageenan was found, except with the most hydrophobic compounds. Analysis of flavor release under nonequilibrium conditions revealed a suppressing effect of lambda-carrageenan on the release rates of aroma compounds, and the extent of decrease in release rates was dependent on the physicochemical characteristics of the aroma compounds, with the largest effect for the most volatile compounds. However, none of the effects was of a magnitude similar to the obtained changes in the macroscopic viscosity, and the suppressing effects are therefore attributable to the thickener and not the physical properties of the increasingly viscous systems.