Effects of tempering with steam on the water distribution of wheat grains and quality properties of wheat flour

Dynamic behaviors of protein and water associated with fresh noodle quality during processing based on different HMW-GSs at Glu-D1

In this study, dynamic behaviors of proteins and water during fresh noodles processing associated with the quality of fresh noodles were systematically investigated by using wheat near-isogenic lines carrying high-molecular-weight glutenin subunits (HMW-GS) 2 + 12, 3 + 12 or 5 + 10 at the Glu-D1 locus. The results showed that subunits 5 + 10 tend to form a complex gluten network and had a poorly hydrated ability, that prevent the intrusion of external water during cooking; subunits 3 + 12 formed a moderate strength gluten network that generated a medium ability to resist the hydrated and mechanical treatment, which explained the highest water absorption and less cooking loss of cooked noodles; while subunits 2 + 12 formed fragile protein aggregates that had a poor ability to resist mechanical. The findings demonstrated that subunits 3 + 12 provided a suitable gluten network which was crucial for intrusion and hydration of external water thus formed a uniform gluten network and excellent fresh noodle quality.

Influence of roasted flaxseed marc flour on rheological, structural, fermentation, water distribution, and migration properties of wheat dough

Roasted flaxseed (RF) marc, which is a by-product obtained from RF oil extraction, has high nutritional value. This study evaluated the impact of RF marc flour on rheological, structural, fermentation, water distribution, and migration properties of the wheat dough. Results showed that adding RF into wheat flour (WF) could effectively increase the water absorption in the dough and retard the retrogradation of starch. The fermentation results revealed that adding RF could improve the gas retention coefficient of dough. Compared to the dough prepared with WF, the doughs enriched with RF had higher tan δ values (ratio of loss modulus G″ to storage modulus G'), indicating a more liquid-like property. The mobility of tightly bound and free water in dough was decreased by adding RF, whereas the distribution of free water was increased. On the one hand, adding RF would dilute the gluten content in dough, resulting in a weaker protein network. On the other hand, the dietary fiber and proteins in RF could offset the gluten dilution effect to some extent. Overall, the results suggested that the substitution level of RF in WF should be below 25% to avoid serious dough quality deterioration, and the RF-WF blended flour could be a potential ingredient to produce wheat products with moist taste. These findings could be useful for guiding the future usage of RF marc in wheat-based products.

Comparison of milling methods on the properties of common buckwheat flour and the quality of wantuan, a traditional Chinese buckwheat food

The microstructural and techno-functional properties of buckwheat flour and its processability for making wantuan, as affected by different milling methods, were investigated. Results showed that the particle sizes (d(0.5)) of the flours made by stone-milling (SM), hammer-milling (HM), laboratory grinding with steaming pretreatment for 5 min (LG-5) and 10 min (LG-10) were 95.5, 111.5, 35.4 and 41.1 μm, respectively. Moreover, SM and HM flours had less liberated starch granules and 20.84%-24.32% higher relative crystallinity than LG-10 flour. Slurries of laboratory-grinded flours showed excellent suspension stability. LG-10 flour had lowest pasting viscosities but greatest storage modulus and loss modulus. Color differences among the wantuan made from different flours were not visibly perceived (ΔE < 5). Wantuan made from LG-5 flour exhibited highest textual quality due to its greatest resilience (0.376), good springiness (0.933) and accepted chewiness (1093.31). Concluding, steaming prior to grinding could improve the qualities of buckwheat flour for wantuan making.

Occurrence of Antibiotic Resistant Bacteria in Flours and Different Plant Powders Used in Cuisine

In recent years, several alimentary diseases have been connected with the consumption or tasting of raw flour and dough. Microbiological quality concern is also raising due to increased consumer demand for plant powders, while some of them can be consumed without prior thermal processing. In this study, we have focused on the occurrence of antibiotic-resistant coliform bacteria and enterococci in flour, plant powder and dough from Slovak retail. Our results indicated the presence of both total and antibiotic-resistant coliform bacteria and enterococci in the flour and powder samples. Lower numbers of the total, as well as resistant bacteria, were detected in flours compared to plant powders. Coliform bacteria isolates were predominantly identified as Klebsiella spp. and Enterobacter spp. Ampicillin resistance appeared in 97% of isolates followed by chloramphenicol resistance (22%) and tetracycline resistance (17%). The presence of the bla_SHV gene was confirmed in 13% of isolates. The tetA and tetE genes were present in 25% of isolates of coliform bacteria. The presence of enterococci was detected only in plant powders. Antibiotic-resistant strains were identified as the following: Enterococcus casseliflavus, E. gallinarium and E. faecium. Despite the isolates showing resistance to vancomycin, the presence of the vanA gene was not detected. The majority of antibiotic-resistant isolates belonged to the group of medium biofilm producers. None of these isolates showed efflux pump overproduction. Antibiotic-resistant coliform bacteria and enterococci were not detected in the processed doughs.

Effect of Tempering Conditions on White Sorghum Milling, Flour, and Bread Properties

The effects of room temperature water, hot water, and steam tempering methods were investigated on sorghum kernel physical properties, milling, flour, and bread-making properties. Overall tempering condition and tempering moisture content were found to have a significant effect on the physical properties. Milling properties were evaluated using a laboratory-scale roller milling flowsheet consisting of four break rolls and eight reduction rolls. Room temperature tempering (18% moisture for 24 h) led to better separation of bran and endosperm without negatively impacting flour quality characteristics i.e., particle size distribution, flour yield, protein, ash, damaged starch, and moisture content. Bread produced from the flour obtained from milling sorghum kernels tempered with room temperature water (18% m.c for 24 h) and hot water (16% m.c at 60 °C for 18 h) displayed better bread-making properties i.e., high firmness, resilience, volume index, higher number of cells, and thinner cell walls when compared to other tempering conditions. Room temperature water tempering treatment (18% m.c for 24 h) could be a better pretreatment process for milling white sorghum kernels without negatively impacting the flour and bread-making quality characteristics.