Influence of Final Baking Technologies in Partially Baked Frozen Gluten-Free Bread Quality

Impact of Gluten-Free Sorghum Bread Genotypes on Glycemic and Antioxidant Responses in Healthy Adults

Sorghum is used to provide good quality gluten-free products due to phytochemicals and low glycemic index (GI). This study aimed to determine the chemical composition, the antioxidant activity and capacity, and the glycemic and insulinemic responses of gluten-free (GF) sorghum bread. GF bread samples were produced with three different sorghum genotypes. The samples were analyzed for chemical composition, resistant starch and dietary fiber content; antioxidant activity by ORAC; antioxidant capacity by FRAP; GI; and insulinemic responses. This double-blind, crossover, randomized clinical trial was conducted with 10 healthy men aged 28.0 ± 4.9 years (77.6 ± 11.7 kg and 24.2 ± 2.3 kg/m2). All sorghum bread showed significantly more fiber than rice bread (control). Brown sorghum bread was classified as low GI, bronze and white as medium GI, and control as high GI. Brown sorghum bread presented a low carbohydrate content, a significant amount of fiber, and a significantly lower 3 h AUC glucose response than those of the control, aside from the highest antioxidant activity value (p ≤ 0.001). Therefore, brown sorghum was superior to other genotypes analyzed in this study, and its production should be encouraged to provide gluten-free products with a better nutritional profile. More research is required to explore the effects of different sorghum genotypes in food products on human health.

Effects of sourdough on improving the textural characteristics of microwave-steamed cake: A perspective from dielectric properties and water distribution

A sourdough combined with microwave heating method was adopted to make steamed cake (SSC), the dough yield, fermentation time and additive amount of sourdough were optimized by Response Surface Methodology (RSM) to obtain microwave-steamed cake (MSSC) with high-quality attributes and then the potential mechanism of sourdough on the improvement of the MSSC texture was investigated. The addition of sourdough with the optimized parameters could greatly improve the specific volume, porosity, hardness, and chewiness of MSSC, which was mainly related to changes in dielectric properties and water distribution. The results of dielectric properties confirmed that sourdough increased the dielectric properties of the system during microwave heating, affecting the microwave heating characteristics. And the changes of water states and distribution by T₂ relaxation analysis showed that sourdough restricted water mobility during heating and facilitated the retention of water trapped in MSSC. Additionally, the scanning electron microscopy (SEM) images indicated that sourdough weakened the gluten network structure, and triggered a looser and smoother microstructure. PRACTICAL APPLICATION: Steamed cake (SSC) is one of the most popular fermented foods in China, while its commercial development is greatly limited by the drawbacks of traditional steam heating. In recent years, the applications of microwave heating and sourdough in cereal-based foods processing have gained more and more interest. However, there is little information about the application of sourdough combined with microwave heating in SSC production. This study revealed that sourdough addition increased the specific volume, porosity, texture, and consumer preference of MSSC, providing a natural, high-efficiency, and easy-to-operate means for the fabrication of high-quality fermented foods.

Acceptability of bread made with hemp (Cannabis sativa subsp. sativa) flour evaluated fresh and following a partial bake method

With an increasing demand for gluten-free foods, there has been an interest in the utilization of nonconventional ingredients to improve the nutritional quality, sensory attributes, and functionality of gluten-free products. Hemp (Cannabis sativa subsp. Sativa) is one of these ingredients that have yet to be thoroughly evaluated. The primary objective of this study was to determine the acceptability and consumers' sensory perceptions of gluten-free bread (GFB) made with hemp flour. The secondary objective was to assess if the acceptability of the bread changes after 45 days of frozen storage following a partial bake method. The first trial (n = 89) instructed participants to assess six fresh bread samples of varying hemp percentages (0%, 5%, 10%, 15%, 20%, and 25%), using check-all-that-apply questionnaire and a 9-point hedonic scale. This procedure was repeated for the second trial (n = 81), which used partially baked bread samples of the same composition. Overall, as the percentage of hemp flour increased, the overall liking of the GFB decreased. The 5% hemp incorporation in the fresh bread and the 15% hemp incorporation or less in the partially baked bread did not significantly differ from the control bread (fresh and partially baked, respectively). Attributes found to drive the liking of bread were smooth (only for the frozen bread), porous, moist, and soft, whereas the attributes that led to disliking were yeasty and dense. In future research, partial baking methods should be varied to assess the optimal freezing and baking ratio that are specific for hemp-based breads. PRACTICAL APPLICATION: The gluten-free bread (GFB) made with 5% hemp incorporation was not significantly different from the control and was acceptable to consumers. The partially baking method is a suitable method to be used with GFBs incorporated with hemp as it did not affect the consumer acceptability. Additionally, hemp flour incorporation in partially baked GFB was acceptable up to 15%. Consumers prefer GFB with hemp that possesses smooth, porous, moist, and soft attributes.

Influence of different flours and starches on gluten-free bread aroma

The aim of this research was to study the effect of different gluten-free flours (yellow and white corn, rice, oat, teff, buckwheat, amaranth and quinoa) and starches (wheat, corn and potato) on the generation of volatile compounds in the fermented doughs and crumbs. Volatile compounds were analyzed by static headspace-gas chromatography/mass spectrometry (SHS-GC/MS). Nine fermentation and lipid oxidation volatile compounds were evaluated, which were found to be the same from dough to crumb but vary in levels. Concentrations of compounds produced during fermentation were higher in doughs whereas those from lipid oxidation were higher in crumbs. The type of flour/starch affected the concentration of these volatile compounds. The proportions of ethanol and 2/3-methylbutanol (fermentation compounds) were higher in dough from yellow and white corn, rice and oat while the proportions of hexanal, 1-pentanol and 2,4-decadienal (lipid oxidation compounds) were higher in the doughs made with starches. The proportions of ethanol and 2/3-methylbutanol were higher in quinoa and amaranth crumbs whilst hexanal, 1-pentanol and 2,4-decadienal were higher in yellow and white corn crumbs.