Department of Food Science and Nutrition, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, Saint Paul, Minnesota, USA.
CW Brabender Instruments Inc, South Hackensack, New Jersey, USA.
J Food Sci. 2022 Aug;87(8):3496-3512. doi: 10.1111/1750-3841.16238. Epub 2022 Jul 4.
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 (R ) 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.
在这项研究中，首次研究了挤压条件（进料水分含量为 20%、24%和 28%，螺杆转速为 200、300 和 400rpm，挤压温度为 130、150 和 170°C）对中间小麦草（IWG）物理和功能特性（水分含量、膨胀比、堆积密度、硬度、吸水率指数[WAI]、水溶性指数[WSI]）的影响。使用响应面法对挤压条件进行建模和优化，以生产膨化 IWG。所有响应的模型决定系数（R）均较高（0.87-0.98）。所有模型均发现具有统计学意义（p<0.05），并通过独立实验进行了验证。通常，所有挤压条件都对所测量的 IWG 特性具有显著影响。提高螺杆速度并降低挤压温度会导致 IWG 挤出物具有较高的膨胀比。这也导致 IWG 挤出物的硬度和堆积密度通常较低。螺杆速度被发现对 WAI 和 WSI 的影响最大，随着螺杆速度的增加，WAI 显著降低（p<0.05），WSI 显著增加（p<0.05）。获得具有高膨胀比和高 WAI 的 IWG 挤出物的最佳条件为 20%进料水分、200-356rpm 螺杆速度和 130-154°C 挤压温度。
挤压蒸煮用于生产膨化 IWG。这项研究为生产膨化 IWG 提供了基础，这可能作为早餐麦片和小吃使用。这对于将 IWG 商业化用于主流食品应用的努力至关重要。
