No abstract

No abstract

No abstract

BACKGROUND During the industrial production of β‐glucan, a protein‐rich fraction remains as a by‐product. Recovery of this protein as oat protein concentrate (OPC) results in a source of cereal protein for food and improves the overall economy of the process. In this study, a yoghurt‐type product is developed by lactic acid fermentation of an OPC suspension after subjection to heat treatment to assure starch gelatinization. RESULTS In detail, the process of yoghurt production involved an initial heating step to 90 °C, followed by 24 h fermentation with a starter culture consisting of Lactobacillus delbrueckii subsp. bulgaricus und Streptococcus thermophilus. The resulting yoghurt‐type product was mildly sour (pH 4.2) with a certain amount of lactic acid (3.3 ± 0.2 g kg−1) and contained 4.9 × 106 cfu g−1 lactobacillus after 24 h fermentation. Scanning electron microscopy revealed a porous network presumably built up from the gelatinized starch fraction containing aggregated structures, between which were assumed to be aggregated oat proteins. Moreover, to a limited extent, proteolysis occurred during fermentation. Thus some of the proteolytic enzymes present in the yoghurt culture cleaved oat protein and released peptides. However, the effect on essential amino acids was small. CONCLUSION The results of this study provide a deeper knowledge into the role of starch and protein in fermented OPC yoghurts. The structure of fermented OPC verifies the applicability of oat protein as an alternative source for yoghurt‐type products. © 2019 Society of Chemical Industry

Hydrocolloids are important ingredients controlling the quality characteristics of the final bakery products. Hydrocolloids are frequently used in gluten-free (GF) recipes, mimicking some rheological properties of gluten, improving dough properties, delaying starch retrogradation and improving bread texture, appearance and stability. Hydrocolloids addition increases viscosity and incorporation of air into the GF dough/batter. Besides their advantages for the technological properties of the GF bread, hydrocolloids addition may impact the glycemic index (GI) of the final product, thus answering the demand of people requiring products with low GI. This review deals with the application of hydrocolloids in GF bread and pasta with a focus on their effect on dough rheology, bread hardness, specific volume, staling and GI.

Theanine (T) and polyphenols (P) enriched fractions obtained from decaffeinated black tea dust by fractionation on a XAD resin, were incorporated into wheat bread formulation. The effect on dough properties and quality characteristics of supplemented breads was investigated. The development time and mixing resistance of dough was significantly increased by P fraction addition, indicating a stronger dough structure. P inhibited the Gram-positive bacteria, while E. coli was only inhibited by T fraction. Addition of P fraction provided an extension of bread shelf life up to 4 days as compared to control bread, while T fraction increased shelf life for 1 day. P fraction hindered the retrogradation of amylopectin which had no antifirming effect in bread. During storage, starch retrogradation in P bread crumbs was significantly retarded as compared with the control. P fraction produced darker, harder and coarser crumb structure and lower loaf volume. Crumb hardness was negatively correlated with bread volume (r =-0.90, p < 0.05). The electronic nose system discriminated the bread odour based on the fraction used. Bread samples of different storage times were distinguished by e-nose with discrimination index above 90.

This study characterized and compared 13 gluten-free (GF) flours (rice, brown rice, maize, oat, millet, teff, amaranth, buckwheat, quinoa, chickpea, gram, tiger nut, and plantain) for their nutritional and functional properties. For all GF flours investigated, starch was the major component, except for gram, chickpea, and tiger nut flours with lower starch content (<45%), but higher fiber content (8.8–35.4%). The higher amount of calcium, magnesium, zinc, potassium, phosphorus, similar values for iron and lower content of sodium in gram, makes this flour a good alternative to chickpea or other GF flour to develop healthier food products. Amaranth flour had a high protein digestibility, while tiger nut and millet flours were less digestible. Gram, chickpea, quinoa, buckwheat, and oat flours fulfilled amino acids recommendation for daily adult intake showing no limiting amino acid. Total polyphenolic content and antioxidant capacity showed higher values for buckwheat, followed by quinoa and maize flours. Gram, chickpea, maize, and quinoa flours are good candidates to improve health conditions due to lower saturated fatty acid content. The findings of this study provide useful insights into GF flours and may contribute to the development of novel gluten-free products like bread, cookies, or pasta.

The properties of starch can be modified by a variety of methods in order to meet desirable technological needs. Electron beam irradiation is able to induce changes in starch properties. The paper deals with investigation of physicochemical and structural modifications of corn starch processed by electron beam up to 50 kGy and evaluation of the technical-economic aspects of starch processing. Paste viscosity, pasting and peak temperatures decreased in a dose-dependent manner, indicating degradation of the macromolecule. Small circular perforations on the granule surface were observed for 50-kGy irradiated sample. Spectral characteristics suffered minor changes, suggesting that the inter-and intramolecular hydrogen bond stability was affected by the electron beam. These modified starches could find applications in foodstuffs requiring low-viscosity starch. A cost estimate of the electron beam processing of corn starch with an average absorbed dose of 30 kGy showed an increase of corn starch price by 16%.