Effect of flaxseed (Linum usitatissimum L.) flour and yerba mate (Ilex paraguariensis) extract on physicochemical and sensory properties of a gluten free corn-based snack.

Flaxseed (Linum usitatissimum L.) and yerba mate (Ilex paraguariensis) are particularly interesting as functional ingredients due to their high content of essential omega 3-fatty acids and antioxidant properties, respectively. The objective of this work was to formulate a corn snack enriched with flaxseed flour and yerba mate extract and evaluate its physicochemical and sensory properties. Flaxseed flour, added at three levels 1, 3 and 5%, increased the water activity, moisture content and cohesiveness, and decreased the hardness and plastic deformation of the samples. The flour also changed the superficial colour and made the microstructure more compact. On the contrary, yerba mate extract (1 and 3%) decreased the water activity, moisture content and cohesiveness, counteracting the effect of flaxseed flour. Yerba mate increased the plastic deformation and the antioxidant activity of the snacks. The colour was not modified and the microstructure was more fragmented in the presence of yerba mate. Sensory evaluation suggested that flaxseed flour and yerba mate affected the flavour but did not modify the colour and crunchiness of the product.

Obtention and characterization of dried gels prepared with whey proteins, honey and hydrocolloids mixture.

BACKGROUND: Large amounts of honey and liquid whey derived from the dairy industry are produced in Argentina. Honey is exported in bulk and whey is transformed into whey protein concentrates and isolates. The objective of this work was to investigate the effect of pH, composition and storage time on the properties of dried gels with honey, whey proteins and hydrocolloids. RESULTS: Color properties varied according to pH and composition. The fracture stress of dried gels prepared with corn starch was higher than that of gels prepared with guar gum in all conditions assayed. Young's modulus was higher at pH 7 for both compositions and increased with storage time. Rubbery characteristics were found in dried gels with guar gum, while both corn starch and guar gum made the microstructure rougher. Multivariate analysis showed that samples could be grouped by pH. Panelists preferred pH 7 products over acidic ones, and no significant differences in sensory properties were found using either corn starch or guar gum in the formulation. CONCLUSION: The results demonstrated that it is possible to generate a new product, which may open new applications for honey and whey in food formulations. © 2017 Society of Chemical Industry.

Structural and functional properties and digital image texture analysis of gelatin, pectin, and carrageenan gels with honey addition.

Gels combined with honey might generate new possibilities of textures in food development. This work explores the structural and functional properties of gelatin (5 g/100 g), pectin (1 g/100 g), and carrageenan (1 g/100 g) gels with different content of honey (0-50 g/100 g). Honey decreased the transparency of gels and made them more yellow-greenish; all of them were firm and uniform, especially at the highest honey content. The water holding capacity increased (63.30-97.90 g/100 g) and moisture content, water activity (0.987-0.884) and syneresis (36.03-1.30 g/100 g) decreased with the addition of honey. This ingredient modified mainly the textural parameters of gelatin (Hardness: 0.82-1.35 N) and carrageenan gels (Hardness: 2.46-2.81 N), whereas only the adhesiveness and the liquid like-behavior were increased in the pectin gels. Honey increased the solid behavior of gelatin gels (G': 54.64-173.37 Pa) but did not modify the rheological parameters of the carrageenan ones. Honey also had a smoothing effect on the microstructure of gels as observed in the scanning electron microscopy micrographs. This effect was also confirmed by the results of the gray level co-occurrence matrix and fractal model's analysis (fractal dimension: 1.797-1.527; lacunarity: 1.687-0.322). The principal component and cluster analysis classified samples by the hydrocolloid used, except the gelatin gel with the highest content of honey, which was differentiated as a separate group. Honey modified the texture, rheology, and microstructure of gels indicating that it is possible to generate new products to be used in other food matrices as texturizers.

A comparative study of texture and rheology of Argentinian honeys from two regions.

The rheological and textural properties of 26 eastern Argentinian honeys from two different regions (North and Central) were investigated. The viscosity curves of the samples were obtained using a rotational rheometer over a temperature range of 10 to 50C. The viscosity decreased with temperature and all honeys showed a Newtonian behavior. The temperature dependence of viscosity was described using the Arrhenius, Williams-Landel-Ferry, Vogel-Taumman-Fulcher, and Power Law models. The glass transition temperatures of honeys were measured with differential scanning calorimetry and values ranged from -42.63 to -47.71C. The glass transition temperature was also predicted with the Williams-Landel-Ferry model and no significant differences were observed with the experimental results. Rheological parameters were obtained by small amplitude oscillation experiments. Results indicated that the viscous modulus was higher than the storage modulus within all the frequency ranges assayed and honeys from the North region were more viscous. Results of the back extrusion test showed that honeys from the Central region are harder and both groups of honeys (North and Central) exhibited the same consistency and adhesivity. PRACTICAL APPLICATIONS: The honey chain production starts with the extraction of the product from the combs, pumping it through pipes and finishes at the packaging of the product. During all these stages, honey viscosity is a key parameter to ensure proper processing and quality control, preventing the waste of economic resources. Determining honey viscosity is of great importance for the industry to select the equipment such as pumps, mixers, filters, centrifuges, heat exchangers, and optimization of industrial processes. The rheological and textural properties of honey are very important in terms of applications related to quality control and authenticity of honeys. Honey authenticity increases the trust of consumers to certified food products. Argentina is one of the leading honey producers and exporters in the world, but information on the rheological, thermal, and textural characteristics of Argentinian honey is very poor in the scientific literature.

Physicochemical parameters and sensory properties of honeys from Buenos Aires region.

The physicochemical parameters (moisture, hydroxymethyl furfural, colour, electrical conductivity, free acidity, glucose, fructose and sucrose) and the sensory properties(aroma, taste, appeareance, texture) were determined in honeys from apiaries of the agricultural, hills and meadow zones of the south east region of Buenos Aires province (Argentina). The analysis of variance showed significant differences among zones in the mean value of hydroximethyl furfural, colour, electrical conductivity and sucrose content. The principal component analysis explained the 70% of the variance among samples with the first two principal components in both cases. The cluster analysis and linear discriminant analysis showed that samples were grouped in relation to the sampling region coinciding with the results of the principal component analysis. Results suggest that could be possible to classify honeys according to the geographic origin based on the physicochemical parameters; however, the sensory properties were not good predictors.