Browsing by Author "Dias, Ema"
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- Comparative physico-chemical characterization of organic flours from wheat, rye and speltPublication . Sousa, Sérgio; Castro, Pedro; Costa, Joana; Bastos, Francisca Casanova; Dias, Ema; Gomes, AnaAim: There is an increasing consumer demand for healthier food products, such as cereal flours, free from pesticides and other contaminants. The production of organic cereals is therefore a solution that can be commercially explored. Moreover, consumers also highly appreciate and value the local production of cereals and flours. Hence, the aim of the current work was to characterize organic flours obtained from three distinct cereals, namely wheat, rye and spelt. The cereals were selected on the basis that they are able to be grown in Portugal as it presents favourable climatic conditions. Methods: Physico-chemical characteristics of each organic cereal flour, crucial for adequate processing, were analysed through distinct methodologies/technologies, such as falling number (enzyme activity), mastersizer (size distribution) and scanning electron microscopy (SEM; morphology), among several others. Results: Results showed that, among the three flours, wheat presented the highest falling number (350), which translates the enzymatic activity of α-amylase (being negatively correlated). Hence, the dough prepared with wheat flour will be harder than those obtained with the flours from the other cereals. Concerning size distribution of the flours’ granules, results showed bimodal distribution regarding wheat and rye flours, while spelt flour resembled a normal distribution. A maximum (peak) was observed for all flours between 20-30 μm, and a second peak was registered at 60 and 135 μm for wheat and rye, respectively. Those results, obtained utilizing a mastersizer, were further corroborated via SEM analysis. X-ray diffraction analysis provided information concerning cristalographic structure, which allowed to determine that the flour with lower cristalinity was rye. Since this characteristic decreases susceptibility to enzymes, it is inferred that rye flour will be the easiest to digest. Differencial scanning calorimetry (DSC) showed similar starch gelatinization temperature between the three flours, although in spelt flour the process was initialized at lower temperature. Fourier- transform infrared spectroscopy (FTIR) analysis revealed similar spectra, disclosing, as expected, the presence of starch and gluten. Conclusion: Knowledge on the physico-chemical properties of each particular organic cereal flour is crucial and must be considered when looking to select one to develop a specific food product.
- Impact of gastrointestinal digestion on the biological activities of new functional cereal-based granules based on by-products from the food industryPublication . Voss, Glenise Bierhalz; Dias, Ema; Gomes, Ana; Pintado, ManuelaIn recent years, the lifestyle and eating habits of the worldwide population have changed, encouraged by finding healthier and more nutritious food habits. In the last years, consumers have been searching for products with high protein content. Additionally, the consumption of cereals products has been expanding, due to the practicality1. In parallel, food industries generate a high amount of by-products, and although these by-products present a rich nutritional composition, most of these by-products are often undervalued and used as animal feed. In this context, the development of functional granules using by-products from the food industry is an opportunity to contribute to the food products diversification and to consumer health and well-being and to valorize the by-products, promoting the circular economy. Thus, the objective of this work was to evaluate the biological activities impacted by the gastrointestinal digestion (GID) of four new functional cereal-based granules, based on the valorisation of acorn and by-products such as wheat bran, wheat germ and okara. Granules were produced by cold extrusion and their formulation were presented in Figure 1. The GID was performed according to the standardized InfoGest protocol (Brodkorb et al., 2019)2. All granules were characterized regarding their nutritional composition. In addition, total polyphenols, antioxidant activity (ABTS and ORAC assays), proteins profile and oligosaccharides were evaluated in each stage of GID (mouth, stomach, intestinal phase), using FPLC and HPLC methods, respectively. All formulations presented the requirements to attain the claim source or rich in protein (19.6 to 29.6%) and rich in fibre (≥6 g of fibre/100 g). During the GID the release of bioactive compounds was observed, and the in vitro antioxidant activity increased in the intestinal stage. Comparing the formulations, it was possible to observe that the F2 (formulation with acorn and okara) presented the highest ORAC values (11041.73 ± 384.98 µM of Trolox) after GID. Although F1 showed the highest polyphenols concentration (0.86 ± 0.02 mg of Gallic acid/ mL of sample) at the end of GID they all presented similar values. Concerning protein profile, all formulations showed after GID the release of peptides with low MW (< 3 KDa). Relatively to the soluble carbohydrates after GID all granules released oligosaccharides with low MW (< 5 KDa). In conclusion, the results indicated that GID improved the antioxidant activity in the functional granules probably due to the release of polyphenols bond to the fiber, thus suggesting health-protecting effects. Furthermore, these by-products can be valorized as potential ingredients for human consumption, reducing the waste in the food chain and satisfying a market niche based on functional and sustainable products.
- New functional food products based on wheat and soybean processing by-productsPublication . Voss, Glenise Bierhalz; Sardão, Rita; Dias, Ema; Gomes, Ana Maria; Pintado, Manuela