Ana Albors

Influence of substituting milk powder for whey powder on yoghurt quality

Abstract Milk whey is an important source of lactose, calcium, milk proteins and soluble vitamins, which make this product be considered as functional food and a source of valuable nutrients. In this work, whey powder was used to substitute partially the milk powder in yoghurt fortification. Five different formulations were obtained and analysed for acidity, pH, gel consistency and microstructure and flow behaviour, colour (CIE L*, a*, b*) and syneresis index, after 1, 15 and 28 storage days at 5°C. Sensory properties were also evaluated after 15 storage days. Results show that the use of whey powder implies a slower acidification rate in yoghurts which becomes a little yellowish. They also show a better flow properties and greater syneresis than those obtained for products prepared with skim mil powder. Yoghurt samples with highest WP percentage (3.64–5.20%) were preferred by the sensorial panel.

EQUILIBRATION OF APPLE TISSUE IN OSMOTIC DEHYDRATION: MICROSTRUCTURAL CHANGES

ABSTRACT The changes in density and porosity and the microstructural development of apple tissue throughout the equilibration in osmotic treatments were analyzed for different osmotic solution concentrations. The effect of vacuum impregnation of the sample with the osmotic solution, before the osmotic treatment was also studied. Two periods were differentiated in the process. For relatively short term treatments (24–48 h) cell walls shrunk or separated from plasmalemma because of the cell water loss while compositional pseudoequilibrium was achieved. Afterwards for long term treatments, a bulk flux of osmotic solution into the fruit tissue occurred in line with the relaxation of mechanical energy accumulated in the deformed cell wall matrix. So, the true equilibrium (chemical plus mechanical), achieved when no changes either in sample composition or weight occurred, implied cell wall sphericity and sample volume recovery. However, some degree of irreversibility was observed in cell wall recovery, especial...

Experiencia en el uso del portafolio por medio de las redes sociales

En la UPV los equipos EICE:QtalNET e IEMA realizan conjuntamente el proyecto PIME “Social ePortafolios” en el que se ensayan diferentes tecnicas de evaluacion por medio de portafolios electronicos y en redes sociales. El objetivo principal del proyecto es elaborar un protocolo que permita usar las redes sociales durante el proceso de creacion de portafolios electronico para la evaluacion de las competencias adquiridas por los alumnos. En este articulo se presenta el proyecto, asi como la experiencia que se esta realizando consistente en experimentar en diversas asignaturas de diferentes titulaciones el portafolios para evaluar. Los alumnos pueden implementar el portafolio a traves de las redes sociales (grupos experimentales) o por medio de un documento (grupos de control). La realizacion en todos los casos es individual. El peso del portafolio en la evaluacion va desde un 60% a un 100% (dependiendo de la asignatura). La defensa se realiza oralmente y a todos los alumnos (tanto si son del grupo experimental como de control) se les proporciona una breve guia para que la estructura pueda ser comparable entre los diferentes portafolios. En el presente articulo se expone el metodo seguido asi como las reflexiones sobre su uso.

Micronised bran-enriched fresh egg tagliatelle: Significance of gums addition on pasta technological features

The aim of the work was to produce fibre-enriched fresh pasta based on micronised wheat bran and durum wheat semolina with appropriate techno-functional properties. Wheat semolina was replaced with fine particle size (50% below 75 µm) wheat bran – up to 11.54% (w/w). A Box–Behnken design with randomised response surface methodology was used to determine a suitable combination of carboxymethylcellulose, xanthan gum and locust bean gum to improve pasta attributes: minimum cooking loss, maximum values for water gain and swelling index, as well as better colour and texture characteristics before and after cooking. The proximate chemical composition of wheat semolina and bran was determined and the microstructure of uncooked pasta was observed as well. From the response surface methodology analysis, it is recommended to use: (i) xanthan gum over 0.6% w/w as it led to bran-enriched pasta with a better developed structure and superior cooking behaviour, (ii) a combination of xanthan gum (0.8% w/w) and carboxymethylcellulose (over 0.6% w/w) to enhance uncooked pasta yellowness.

High fibre tiger nut pasta and xanthan gum: cooking quality, microstructure, physico-chemical properties and consumer acceptance

The feasibility of replacing wheat semolina by tiger nut flour (20 and 40%) and xanthan gum (1%) in order to obtain high fibre dry pappardelle with fair techno-functional, structural and sensory attributes, was assessed. The cooking properties, texture, colour and sensory acceptance of uncooked and cooked pasta were evaluated. The proximate chemical composition of the raw materials, and the microstructure of the dry pasta were also assessed. The results in this manuscript address the improved nutritional value in terms of its dietary fibre, mineral content, oleic and linoleic acids, and the positive effects on the textural characteristics and cooking behaviour achieved on dry tiger nut based pappardelle using 1% of xanthan gum as a structural agent. Micrographs revealed in fact that the gluten network was better formed when xanthan gum was used. Furthermore, the obtained results seem to support that consumers would prefer pappardelle with 40% tiger nut flour.