1,720,992 research outputs found
Microencapsulation of nettle and tomato exctracts by freeze-drying: technological functionality and stability in glassy state
No full textRole of proteins in the microstructure, rheology, tribology and sensory perception of plant-based custards
No full textCustard is a dairy dessert typically composed of milk, egg yolk, starch and sugars. In recent years, the food market has shown an increased demand for plant-based dairy alternatives. This study evaluated the role of plant-protein isolates (namely pea, potato and soy) in the physicochemical, rheological and microstructural characteristics of plant-based (no-dairy, no-egg) custards and in their sensory perception. The protein isolates were selected based on differences in gelling behaviour and were tested at three different concentrations (2.5, 4 and 10 %) under the same process conditions. The results were compared to both a conventional dairy-based custard with egg yolk and a plant-based formulation without proteins. In general, custards were characterized by a microstructure of swollen starch granules and a protein network. Increasing protein concentration enhanced the continuity of the protein network, which increased viscosity and exerted a space limiting effect on the swollen starch granules. The viscosity of the custards positively correlated to mouth-coating, compactness and stickiness perception. Melting rate perception was negatively related to thickness and compactness. The particle size of the protein aggregates was positively related to graininess perception and negatively with creaminess. Potato proteins formed a dominant network already at low concentrations and the substantial enhancement in elastic behaviour and viscosity had negative effects on texture perception of the plant-based custards compared to the animal-based reference. On the contrary, soy and pea protein formed at low concentrations less extensive networks compared to potato, resulting in rheological properties most closely resembling those of the reference custard. However, pea protein showed a tendency to form a less homogeneous protein network with large aggregates, that negatively affected creaminess. Overall, under the conditions of this study, matching particle size of the protein aggregates, viscosity, G’ and critical strain led to plant based samples with mouthfeel attributes similar to those of the animal-based reference
Il Museo archeologico di Ascoli Piceno. Palazzo Panichi di Ascoli: continuità e rinnovamento cinquecentesco della città
No full textPublished as part of the initiatives proposed by the Directorate General for Museums of the Ministry of Culture, the paper presents the results of recent research on the history and dynamics of musealisation of archaeological collections in the Marche region. The text presents research elements regarding the communication of museum values to the public
Pulsed electric fields (PEF) as hot air drying pre-treatment: Effect on quality and functional properties of saffron (Crocus sativus L.)
Full text linkThis study aimed to investigate the use of pulsed electric fields (PEF) (2 kV/ cm; 1.5 KJ kg−1) as pre-treatment to the hot air drying process for the improvement of quality and functional properties of saffron. Analysis of flavouring, aroma and colouring strength (E1%λmax), crocins pattern (UHPLC-MS/MS), total polyphenol content (TPC) and antioxidant activity (AOA) were performed after processing and during aging at room temperature. Microstructure of fresh and processed stigmas was also assessed. PEF decreased (≈ −41%) the flavour, aroma and colouring strength of stigmas and negatively influenced the safranal production during drying; nevertheless, stigmas pre-treated by PEF (PD) after 3 months of aging showed quality properties similar to those of not pre-treated sample (D). Analysis of crocins by UHPLC-MS/MS highlighted a negative effect of PEF on trans-cis crocins ratio and showed poor correlation with colour strength. PEF did not influence the TPC of fresh stigmas but after drying and aging PD showed the highest value among the samples. PEF negatively influenced (−24%) the AOA of fresh stigma while favored its increase during drying. Loss of AOA during aging (up to 86%) was processing independent. Microstructure analysis showed that PEF treatment strongly impaired the stigmas' cells, thus enhancing the extractability of intracellular compounds
Pea protein isolates: emulsification properties as affected by preliminary pretreatments
No full textThe surface and emulsifying properties of a commercial pea protein isolate in oil-in-water model emulsions and the role of insoluble residues in emulsion stability were investigated. Droplet size distribution, flocculation index, microstructure, and protein coverage of the emulsions were evaluated. The insoluble fraction positively contributed to the pea proteins’ emulsifying properties, allowing the formation of emulsions with higher dispersion degree, especially at low isolate concentration, with an enhancement of the physical stability
Colloidal properties and stability of olive oil-in water emulsions stabilized by starch particles
No full textStability and tribological properties of oil-in-water emulsions stabilized with native corn starch and olive leaves phenolic extracts
No full textIn this work, the tribological behaviour of o/w model emulsions stabilized by native corn starch particles in association with a surface-active olive leaf phenolic extract (OLE) was studied. Preliminarily, starch particles were submitted to a high-pressure homogenization pre-treatment and were then separated, by sedimentation, into small (<5 μm, centered on 2.5 μm) and large (<50 μm, centered on 17 μm) particles. Oil-in-water emulsions (10 % dispersed phase, w/v) were prepared using native corn starch particles in the presence of OLE as an emulsifier and characterized for particle size, microstructure and tribological behaviour. OLE and starch particles were both needed for system structuration, providing stability with different mechanisms. OLE triggered oil droplet formation acting as a low molecular weight emulsifier, while starch particles played a different role in the stabilization of the emulsions based on their size: the small starch particles provide stability by adsorbing onto the o/w interface, while the large particles provide stability by forming an interconnected network in the continuous phase, which embedded OLE-stabilized oil droplets. The tribological study showed that emulsions stabilized by small particles showed higher friction coefficients. In these emulsions, the stable emulsion droplets provided particle lubrication. In emulsions stabilized by large particles, lower friction coefficients were observed, which was due to the low stability of the oil droplets. The oil droplets could easily coalesce under flow, causing the formation of an oil film, which was more efficient in lowering the friction coefficient than the oil droplets stabilized with smaller particles. Such findings demonstrated that the size of starch particles played an important role in the stabilization mechanism of the emulsions as well as of their lubrication properties, and can be used to control different properties of emulsions
- …
