Samuel Verdú

Predicting Gilthead Sea Bream (Sparus aurata) Freshness by a Novel Combined Technique of 3D Imaging and SW-NIR Spectral Analysis

A technique that combines the spatial resolution of a 3D structured-light (SL) imaging system with the spectral analysis of a hyperspectral short-wave near infrared system was developed for freshness predictions of gilthead sea bream on the first storage days (Days 0–6). This novel approach allows the hyperspectral analysis of very specific fish areas, which provides more information for freshness estimations. The SL system obtains a 3D reconstruction of fish, and an automatic method locates gilthead’s pupils and irises. Once these regions are positioned, the hyperspectral camera acquires spectral information and a multivariate statistical study is done. The best region is the pupil with an R2 of 0.92 and an RMSE of 0.651 for predictions. We conclude that the combination of 3D technology with the hyperspectral analysis offers plenty of potential and is a very promising technique to non destructively predict gilthead freshness.

Effect of tiger-nut (Cyperus esculentus) milk co-product on the surface and diffusional properties of a wheat-based matrix

The food processing industry generates huge volumes of waste and co-products which still contain valuable compounds. Tiger-nut milk production generates large amounts of a co-product with a high insoluble fibre content, which is interesting as a bioactive component from a nutritional viewpoint. This co-product is formed by two different tissues in composition, particle size and colour terms, so two different flours were obtained from them. Both flours were included in a wheat-based matrix at different substitution levels: 5%, 10% and 20% (d.b). The surface tension of matrices, and the wettability and diffusion of water and oil, were studied. The results showed the matrixs reduced capacity to interact with solvents, principally from the 10% substitution level, with diminished surface tension, and a longer time was needed for both water and oil to wet and diffuse.

Non destructive monitoring of the yoghurt fermentation phase by an image analysis of laser-diffraction patterns: Characterization of cow’s, goat’s and sheep’s milk

Monitoring yogurt fermentation by the image analysis of diffraction patterns generated by the laser-milk interaction was explored. Cows, goats and sheeps milks were tested. Destructive physico-chemical analyses were done after capturing images during the processes to study the relationships between data blocks. Information from images was explored by applying a spectral phasor from which regions of interest were determined in each image channel. The histograms of frequencies from each region were extracted, which showed evolution according to textural modifications. Examining the image data by multivariate analyses allowed us to know that the captured variance from the diffraction patterns affected both milk type and texture changes. When regression studies were performed to model the physico-chemical parameters, satisfactory quantifications were obtained (from R2 = 0.82 to 0.99) for each milk type and for a hybrid model that included them all. This proved that the studied patterns had a common fraction of variance during this processing, independently of milk type.