11 research outputs found

    Quality of bread baked from frozen dough - effects of rye, and sugar content, kneading time and proofing profile

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    The objectives of this study were to evaluate whether proofing profile influences volume and crumb firmness in bread baked from frozen dough, and whether rye or sugar content and different kneading times affect the microstructure of the frozen dough. Microscopy was used to explain the differences.Wheat doughs mixed with rye ("rye") and with sugar ("sweet") were frozen after 3 different proofing times (0, 18, and 38 min) and visualized with confocal laser scanning microscopy and 3-dimensional micro-computed tomography. The baked breads were evaluated for volume and texture. Breads from un-proofed frozen dough allowed to proof after thawing showed the highest volume (4.0 cm(3)/g) and the softest crumb texture. The pre-proofed sweet bread had firmer crumbs and lower volume (2.5-3.0 cm(3)/g) than the pre-proofed rye bread (2.7-3.7 cm(3)/g). Reasons for the differences in quality parameters between the rye and sweet breads were investigated by studying the different influences of kneading time and sugar content on fresh and frozen dough. The gluten network was found to be more homogeneously distributed in doughs with longer kneading times and lower sugar content, and less well distributed and more lumped in frozen than in fresh dough

    Towards attractive texture modified foods with increased fiber content for dysphagia via 3D printing and 3D scanning

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    As life expectancy increases so do age related problems such as swallowing disorders, dysphagia, which affects 10%–30% of people over 65 years old. For dysphagia patients the texture and rheological properties of the food, and the bolus, is critical to avoid choking and pneumonia. Texture modified foods, timbals, are often served to these patients due to their ease of swallowing. The main concern with these foods is that they do not look visually alike the food they replace, which can decrease the patient’s appetite and lead to reduced food intake and frailty. This study aims to improve both the visual appearance of texturized food as well as the energy density and fiber content of the timbal formulation. 3D scanning and additive manufacturing (3D Printing) were used to produce meals more reminiscent of original food items, increasing their visual appeal. Rheology was used to ensure the original flow profile was maintained as the timbal was reformulated by reducing starch contents and partially replacing with dietary fibers. The amount of starch was reduced from 8.7 wt% in the original formulation to 3.5 wt% and partially replaced with 3 wt% citrus fiber, while maintaining properties suitable for both swallowing and 3D printing. The resulting formulation has improved nutritional properties, while remaining suitable for constructing visually appealing meals, as demonstrated by 3Dprinting a chicken drumstick from a model generated with 3D scanning

    Long-term frozen storage of wheat bread and dough - Effect of time, temperature and fibre on sensory quality, microstructure and state of water

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    The objective of this study was to determine effect of storage time, storage temperature and addition of fibre on sensory quality, state of water, microstructure and texture of bread and dough. Samples with and without fibre, were stored frozen for 2, 3.5 and 6 months at temperatures of 19, 16 and 8 C as dough and bread. Sensory quality was evaluated by a trained analytical panel. Microstructure was analysed by light microscopy. Texture measurements were performed on bread, and the state of water was measured by differential scanning calorimetry. Bread without fibre stored as dough at 19 C was the sample most like freshly baked bread. Sensory evaluation also confirmed that quality of the final bread was improved if samples were stored as dough compared to stored as bread. The microstructure had larger gaps between the starch and gluten phases when stored at warmer temperatures, due to retrogradation of starch, dehydration of gluten and water migration. DSC measurements showed that bread stored at 19 C gained extra amount of freezable water, but lost ice after storage at 8 C. Texture measurements showed that firmness increased with extended storage time. Bread stored at 8 C had lowest quality in all measurements

    Effect of anthocyanins on lipid oxidation and microbial spoilage in value-added emulsions with bilberry seed oil, anthocyanins and cold set whey protein hydrogels

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    The objective of this work was to explore the storage properties of a structured oil-in-water emulsion containing both water- and fat-soluble bioactive compounds from bilberries (Vaccinium myrtillus L.). Bilberry seed oil (BSO) was dispersed in a continuous aqueous phase of anthocyanins (AC) and whey protein isolate. The microstructure was evaluated using light microscopy and the effect of anthocyanins on lipid oxidation and microbial growth was investigated. The results showed that it was possible to generate a stable emulsion structure that resisted phase separation during 25 weeks of storage. Gas chromatography–mass spectrometry measurements of the fatty acids in the BSO during storage showed that AC had a protective effect against lipid oxidation. The AC did not have an antimicrobial effect against the investigated strains Zygosaccharomyces bailii (ATCC 42476) and Aspergillus niger (ATCC 6275 (M68)).This research was financially supported by the ERA-Net, SUSFOOD project ‘Sustainable &amp; Healthy: Development of sustainable processing technologies for converting by-products into healthy, added-value ingredients and food products’, Swedish Research Council Formas , Grant: 2014-49</p

    Flow Behaviour and Microstructure of a β-Glucan Concentrate

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    The extensional viscosity is an important rheological characteristic of polymer melts. It is however not as frequently reported on as the shear viscosity. The extensional viscosity is of special interest when considering polymeric materials for foaming and film blowing processes. Here, the extensional (and shear) viscosity along with the melt strength and the tensile properties of the corresponding solid film of a β-glucan concentrate are reported on. A capillary viscometer equipped with a hyperbolic die, yielding a contraction flow, was used to assess the extensional viscosity of the aqueous β-glucan compound at room temperature and at elevated temperatures (110 and 130 °C). In general, the extensional viscosity as well as the shear viscosity decreased with increasing deformation rate. The influence of two different amounts of added water (40 and 50%) was also examined. As expected, both types of viscosities decreased with increasing temperature. It is suggested that gelatinization of the starch fraction in the concentrate at 110 and 130 °C contributes to temperature dependence of the viscosity. To some extent, this is supported by light microscopy and confocal scanning laser microscopy studies of the microstructure of the materials. The results reported here indicate that the β-glucan concentrate might, after some modifications, be used as a complement to fossil-based polymers and processed by conventional manufacturing techniques.
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