1,721,097 research outputs found
Brewers’ spent grain exploitation in the production of fibre enriched fresh egg pasta
Full text linkBrewers’ spent grain (BSG) is a low-value co-product of the brewing industry produced in large quantities. Owing to its composition rich in proteins, fibre and phenolic compounds, BSG has the potential to be utilised in food products, providing health benefits for consumers.
The aim of this work was to evaluate the possibility of BSG exploitation in the production of fibre enriched fresh egg pasta. To improve pasta structure, the addition of egg white powder (EWP) was also evaluated.
In order to simultaneously study the effect of the two considered factors (BSG and EWP amount), an inscribed Central Composite Design was developed. Pasta samples were produced as sheets for lasagna, using wheat flour, semolina, 20% whole egg, and keeping moisture to a constant level. BSG ranged from 6.2 to 25% and EWP between 0 and 12%.
Highly significant models (p<0.001) of different complexity were calculated for all the pasta quality parameters, except for weight increase during cooking. The most influencing factor resulted to be the amount of BSG, which directly affected the matter loss during cooking, the break load of raw pasta, the Young’s modulus of both raw and cooked pasta and the CIE a* parameter of raw and cooked samples. Moreover, as the amount of BSG increased, break strain of raw and cooked pasta, break load of cooked pasta, and CIE L* and b* parameters of both raw and cooked pasta decreased. The addition of EWP improved structural characteristics of cooked pasta, due to the tighter protein network developed by increased amount of ovalbumin.
In conclusion, this research demonstrated that BSG can be successfully exploited in the production of fibre enriched fresh egg pasta, thus contributing to a higher sustainability of the brewing process
Brewer's spent grain valorization in fiber-enriched fresh egg pasta production: Modelling and optimization study
No full textThe aim of this work was to valorize brewer’s spent grains (BSG) in the production of a fiber-enriched fresh egg pasta. To improve pasta structure, the addition of egg white powder (EWP) was also evaluated. An inscribed Central Composite Design was developed, ranging BSG from 3 to 25 g/100g and EWP from 0 to 12 g/100g. Highly significant models (p < 0.001) of different complexity were calculated for all the pasta quality parameters, except for thickness and weight increase during cooking. BSG addition significantly lowered average break strain of pasta with respect to a standard formulation produced without fiber (26±10% vs. 54±4%, for raw sheets; 25±8% vs. 54±1%, for cooked sheets). On the contrary, the addition of EWP improved mechanical properties of cooked pasta due to the tighter protein network developed by ovalbumin. With the highest EWP amount, break load (6.5±0.4 N) and strain (33±4%) of cooked pasta resulted significantly higher than in sample without EWP (1.4±0.1 N and 18±1%, respectively). Optimization of pasta quality by the desirability function demonstrated that BSG and EWP can be successfully exploited in the production of a fresh egg pasta “source of fiber”, thus contributing to a higher sustainability of the brewing process
Surface texture of fresh egg pasta enriched with brewers’ spent grain
Full text linkTraditional quality parameters for pasta products are weight increase and matter loss during cooking as well as the mechanical properties of both raw and cooked products. Furthermore, aspect features (e.g. colour, shape, size, surface texture) are evaluated as they can play an important role in consumer’s acceptability.
The aim of this work was to define the surface texture properties of fresh egg pasta enriched with brewers’ spent grain (BSG) and egg white powder (EWP) by image analysis techniques. BSG is a low-value co-product of the brewing industry, produced in large quantities every year. Its use in pasta products can contribute to increase its value and the sustainability of the brewing process. However, the high amount of fibre can damage the gluten network and thus the pasta texture properties. For this reason, EWP was added as a protein network improver.
Thirteen pasta samples, produced as sheets for lasagna using wheat flour, semolina, 20% whole egg, 6.2-25% BSG, 0-12% EWP and keeping moisture to a constant level, were characterized by means of heterogeneity (HTG) and grey level co-occurrence matrix (GLCM) indices. Correlations between surface texture properties and traditional quality parameters were also evaluated.
The results showed that the image analysis techniques applied are able to evidence differences within and between raw and cooked samples, even if cooking process reduces these differences. Furthermore, highly significant correlations (p<0.001) were found among the image analysis indices (HTG, contrast, entropy and homogeneity) and common quality parameters (i.e. CIE L*a*b* values, break deformation, Young’s modulus and matter loss).
In conclusion, BSG resulted the most influencing factor affecting surface texture indices. Image analysis can thus be applied to identify pasta samples with different fibre content
"Sea wave spectra by electromagnetic techniques"
No full textSea wave measurements have been carried out in the Sicilian Channel using a navigational radar for the lower-frequency component and a teflon-coated wire (Goubau line) for the high-frequency component. The results are discussed and the continuity of the complete spectrum is clearly proved
GLUTEN-FREE BREAD: OPTIMIZATION OF FORMULATION AND PROCESS CONDITIONS
Full text linkThe aim of this PhD research project was to identify the formulations and to define the process conditions that most influence the quality and the shelf-life of gluten-free (GF) bread. Raw materials that are commonly used in GF bread production were first characterized, in particular as regards the rheological properties of different starchy gels during a short term ageing. Waxy rice flour (WRF) and rice bran (RB), at 25% and 50% substitution level, came out to be very effective in reducing gel stiffness and storage modulus (G’) of the mixtures containing corn starch (CS) or rice flour (RF). The effects of High Hydrostatic Pressure treatments on CS, RF and WRF were also investigated. A partial gelatinization of RF treated at 400MPa and 600MPa was evidenced by the viscoamylographic test and the formation of a more compact structure and a higher water retention capacity were registered for CS treated at 600MPa. The effect of Psyllium (Psy) and sugar beet (SB) fibers on dough and bread properties was also evaluated. The presence of 2.5% Psy generally determined an increase of dough height and CO2 production during leavening. Psy fiber also showed an anti-staling effect, higher than SB fiber. Taking into account all these results, a GF sourdough (SD) containing selected bacteria and yeasts (Lactobacillus sanfranciscensis and Candida humilis) was developed; then it was constantly refreshed and monitored in terms of number and type of microorganisms, capability to produce/retain CO2 and pH variations. When a stable microbial association was achieved, as well as constant SD properties, some breadmaking trials were performed. GF SD combined with compressed yeast resulted an excellent opportunity to improve GF bread quality and shelf-life
Optimization of a low fat and high resistant starch biscuit formulation
Full text linkThe detrimental effects of food over-consumption are raising a growing concern worldwide, implying high sanitary and social costs. Dietary-correlated diseases are considered among the leading risk factors of mortality. In this context, the production of foods able to satisfy dietary restrictions while maintaining acceptable structural and sensory characteristics is still a great challenge for industries. In particular, the relationships amongst food processing, texture and nutritional characteristics are seldom considered.
This work represents the first phase of a wider project aiming to investigate how different production technologies can be used in order to obtain low fat (LF) and low glycaemic index (LGI) biscuits with quality features comparable to those of the traditional counterparts and a better nutritional functionality. In particular, a Central Composite Design of Experiment (CCD) has been developed in order to optimize the LF-LGI biscuit formulation. The reduction (0-50%) of vegetable shortening and the substitution rate (0-80%) of wheat flour with a high amylose maize starch (source of resistant starch) have been considered as CCD factors. Thus, a total of 13 production trials have been planned, including four replicates of the central point.
Rheological properties and density of the biscuit doughs were analysed. Biscuits were characterized in terms of proximate composition, resistant starch content, geometrical features, colour, milk absorption, and texture (by means of a three-point bending test). Response surface methodology and desirability function will be applied to the analytical data, in order to study the main effects and their interaction and to optimize the biscuit formulation.
Results of this part of the wider project will increase the knowledge about the effects of fat reduction and resistant starch addition on biscuit quality characteristics. They will represent a reliable starting point for the subsequent study of the impact of production technology on structure and nutritional features of the product
Effectiveness of rice bran in delaying starch retrogradation during ageing
No full textThe high amount of starch contained in gluten-free baked products is largely responsible for their low nutritional value and fast quality decay during ageing. Starch retrogradation, in fact, is the major phenomenon involved in bread staling. The aim of this research was to evaluate the rheological properties of gels obtained from corn starch (CS), rice flour (RF) and their mixture (50CS-50RF), and the capability of rice bran (RB) to reduce starch retrogradation when added at different ratios (25% and 50%), in order to increase the shelf-life of starch-containing foods. Gels were prepared by means of the Brabender® Micro-Visco-Amylograph (MVA) (Mariotti et al., 2005) and their rheological properties, during a 7 days storage period at 4°C, were evaluated both through compression test (TA-HDplus Texture Analyzer) up to 30% deformation, and frequency sweep test (Physica MCR 300 Rheometer) performed over the range 0.1-10Hz at 1% strain. During ageing, gels consistency increased at different extents and rates. Samples containing CS showed the highest stiffness (CS: 3.34+/-0.11N/mm, 50CS-50RF: 3.33+/-0.03N/mm) and the highest storage modulus (G’; CS=1393+/-25Pa, 50CS-50RF=972+/-8Pa at 1Hz), after 7 days of storage at 4°C. On the contrary, RB did not form a gel in the experimental conditions adopted for the MVA test. If added at 25% or 50% to CS or RF as well to their mixture, RB originated weak gels and resulted very effective in delaying starchy gels hardening. Gels obtained from 50CS-50RB and 50RF-50RB, in fact, remained rather soft at the end of the storage period, exhibiting stiffness values equal to 0.90+/-0.01N/mm and 0.60+/-0.03N/mm, respectively. Furthermore, the presence of RB, at 25% and 50% substitution levels, strongly reduced the G’ values of the gels containing CS or RF (e.g. 50CS-50RB: G’=128+/-6Pa, 50RF-50RB: G’=76+/-1Pa, at 1Hz) and, for the same gels, it caused the overlapping of G’ curves up to 7 days storage, indicating very slow hardening kinetics. The results obtained thus highlight the possibility to enhance both the shelf-life of gluten-free baked products and their nutritional value by including RB among the other ingredients. The aim of the future research is to better identify the proper amount of RB to be used, in order to allow an appropriate handling of the dough and to enhance the maintenance of gluten-free baked goods softness during storage
Gluten-free bread. II. Compressed yeast versus gluten-free sourdough
No full textThe use of the sourdough as a form of leavening is one of the oldest biotechnological processes in baked goods production. When used in optimised amounts, in fact, sourdough can improve the volume, texture, flavor, and nutritional value of bread and can increase its shelf-life by retarding the staling process and by protecting bread from mould and bacterial spoilage (Moroni et al., 2009). However, few attempts have been made for producing and characterising GF sourdoughs and the functional properties of the resulting breads. In this contest, the aim of this study was to compare the properties and quality of GF breads obtained using an in-lab developed GF-sourdough (SD) (see: Gluten-free bread. I. Development of a gluten-free sourdough), compressed yeast (CY; Saccharomyces cerevisiae) or their mixture (SD+CY) as leavening agents. The different starters were added in proper amounts to a GF mixture containing corn starch, rice flour, pea isolate, hydrocolloids and fiber as main ingredients (the optimized recipe comes from previous studies; Mariotti et al., 2009). The resulting doughs were characterized in terms of number and type of microorganisms, dough consistency, dough titratable acidity, pH and capability to produce and retain CO2. Breadmaking was performed as reported by Mariotti et al. (2013), with some adjustments due to the different raw materials used in the current GF recipe. After baking, the loaves were removed from the moulds and cooled at room temperature before being characterized (t0) for weight, height, specific volume, crust and crumb color, moisture, aw, crumb hardness. Crumb surface aspect was also evaluated, by means of Image Analysis techniques. Breads were characterized also during storage (up to 69h) at controlled conditions (25°C, 60%RH). The main results will be presented. Significant (P<0.05) differences were evidenced among the 3 different types of GF breads, in particular in terms of maximum height (SD: 4.51±0.15cm; SD+CY: 4.83±0.24cm; CY: 5.34±0.09cm), specific volume (SD: 1.69±0.11mL/g; SD+CY: 2.54±0.13mL/g; CY: 2.65±012mL/g), and crumb hardness (SD: 8.73±0.81N; SD+CY: 2.74±0.11N; CY: 1.61±0.19N; to). The higher values of crumb hardness for SD are probably due to its lower development during breadmaking. However, CY crumb exhibited a crumbly behavior during storage, that was absent in SD. From a general point of view, when SD was used in combination with CY a synergic effect was highlighted and an improvement of the overall GF bread quality and shelf-life was achieved. Further studies are in progress to optimise the amount of the developed GF sourdough to be used in the breadmaking process, in order to exploit at the most all its positive functionalities
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