Tempering Improves Flour Properties of Refined Intermediate Wheatgrass (Thinopyrum intermedium)

Strategy for Enhancing Wheat Drying Efficiency and Flour Quality: Hybridization of Tempering and Hot Air Drying

The moderate processing of wheat is increasingly valued. One of the technological means to achieve moderate processing is the hybridization of tempering and hot air drying for postharvest wheat. The initial moisture content at onset of tempering (IMCOT) of wheat significantly influences the efficiency of hot air drying as well as the yield and quality of wheat flour. This study investigates the effects of varying IMCOT and tempering durations on the drying characteristics of wheat, the flour yield, the flour properties, and the properties of flour slurries. The findings revealed that tempering treatments reduced the drying time and altered the pasting characteristics of the flour slurries. This phenomenon could be attributed to the alteration of the kernel structure and starch destruction caused by tempering treatment. Tempering significantly (P < 0.05) affected the protein content and wet gluten content of wheat flour (WF). For the effect of IMCOT, the shortest drying time (35 min) was observed at an IMCOT of 0.17 g/g d.b., while the highest wet gluten content of WF was achieved when it was 0.19 g/g d.b. The lowest breakdown value (908.00 Brabender Units, BU) and highest setback value (811.50 BU) of WF were observed at an IMCOT of 0.19 g/g d.b. For the effect of tempering duration, the shortest drying time (35 min) was achieved at a tempering duration of 40 min. Tempering duration improved the whiteness and brightness of the flour, as well as increased its protein content. Considering the drying efficiency and the quality attribute, the optimal tempering condition was the IMCOT of 0.19 g/g d.b. and a tempering duration of 40 min.

Improving the Nutritional Profile of Intermediate Wheatgrass by Solid-State Fermentation with Aspergillus oryzae Strains

Aspergillus oryzae has been used to ferment various cereal grains throughout history, as seen in the examples of sake, soy sauce, and miso. It is known that this fermentation enhances the nutritional quality of the raw materials by breaking down complex molecules into simpler, more digestible forms and increasing the bioactive compounds. In this study, intermediate wheatgrass (IWG) was fermented with three different strains of A. oryzae suitable for making sake, soy sauce, and miso. Whole IWG flour was mixed with water (1:2 w/w), autoclaved at 121 °C for 20 min, cooled, mixed with A. oryzae spores, and fermented for seven days at 30 °C. Sugars, protein, amino acids, kojic acid, total phenolic content, total flavonoid content, and DPPH radical scavenging activity were measured. The protein content increased significantly (p < 0.05) from 18.0 g/100 g to over 30 g/100 g after seven days. Lysine showed a positive correlation with protein content across all three strains, with its ratio increasing as the protein content increased, while all other essential amino acids displayed a negative correlation and a decreasing ratio with the protein content. Autoclaving increased the verbascose content of IWG, and further increases were observed during the first two days of fermentation across all three strains, followed by a subsequent decline. Peak glucose content was observed on days 3~4 but also decreased in the subsequent days. Total phenolic content, total flavonoid content, kojic acid, and DPPH scavenging activity peaked around day 4~5 for all three strains, followed by a slight decrease in the subsequent days. The findings of this study highlight the potential of solid-state fermentation to improve the nutritional profile of IWG, emphasizing that the selection of A. oryzae strains and the fermentation duration can affect the fermentation outcome and nutritional enhancements.

Optimizing the extrusion conditions for the production of expanded intermediate wheatgrass (Thinopyrum intermedium) products

Abstract

In this study, the effects of extrusion conditions such as feed moisture content (20%, 24%, and 28%), screw speed (200, 300, and 400 rpm), and extrusion temperature (130, 150, and 170°C) on the physical and functional properties (moisture content, expansion ratio, bulk density, hardness, water absorption index [WAI], water solubility index [WSI]) of intermediate wheatgrass (IWG) were investigated for the first time. Response surface methodology was used to model and optimize the extrusion conditions to produce expanded IWG. The model coefficient of determination (R²) was high for all the responses (0.87–0.98). All the models were found to be significant (p < 0.05) and were validated with independent experiments. Generally, all the extrusion conditions were found to have significant effects on the IWG properties measured. Increasing the screw speed and decreasing the extrusion temperature resulted in IWG extrudates with a high expansion ratio. This also resulted in IWG extrudates with generally low hardness and bulk density. Screw speed was found to have the most significant effect on the WAI and WSI, with increasing screw speed resulting in a significant (p < 0.05) decrease in WAI and a significant (p < 0.05) increase in WSI. The optimum conditions for obtaining an IWG extrudate with a high expansion ratio and WAI were found to be 20% feed moisture, 200 –356 rpm screw speed, and 130–154°C extrusion temperature.

Practical Application

Extrusion cooking was employed in the production of expanded IWG. This research could provide a foundation to produce expanded IWG, which can potentially be used as breakfast cereals and snacks. This is critical in the efforts to commercialize IWG for mainstream food applications.

Effect of Bran Pre-Treatment with Endoxylanase on the Characteristics of Intermediate Wheatgrass (Thinopyrum intermedium) Bread

Previous work indicated that bran removal promotes network formation in breads prepared from intermediate wheatgrass (IWG) flour. However, refinement reduces yields as well as contents of nutritionally beneficial compounds such as fiber. This study evaluated xylanase pretreatment of IWG bran as a processing option to enhance the properties of bread made with half of the original bran content. Xylanase pretreatment did not affect stickiness but significantly reduced hardness and increased specific loaf volumes compared to negative (without xylanase) and positive controls (with xylanase but without pretreatment). However, the surface of breads with pretreated bran was uneven due to structural collapse during baking. Fewer but larger gas cells were present due to pretreatment. Addition of ascorbic acid modulated these effects, but did not prevent uneven surfaces. Accessible thiol concentrations were slightly but significantly increased by xylanase pretreatment, possibly due to a less compact crumb structure. Endogenous xylanases (apparent activity 0.46 and 5.81 XU/g in flour and bran, respectively) may have been activated during the pretreatment. Moreover, Triticum aestivum xylanase inhibitor activity was also detected (193 and 410 InU/g in flour and bran). Overall, xylanase pretreatment facilitates incorporation of IWG bran into breads, but more research is needed to improve bread appearance.

Current Trends in the Realm of Baking: When Indulgent Consumers Demand Healthy Sustainable Foods

The term "baked goods" encompasses multiple food products made from flour (typically wheat flour) [...].