School of Food Science, Washington State University, Pullman, Washington, USA.
Texture Analysis and Extrusion, Anton Paar USA Inc., Ashland, Virginia, USA.
J Food Sci. 2024 Nov;89(11):7760-7775. doi: 10.1111/1750-3841.17403. Epub 2024 Oct 16.
Corn starch-based direct expanded products incorporated with 2% and 10% (w/w) sugar (fructose, glucose, sucrose, and xylose) were produced using a 20 mm co-rotating twin-screw extruder. The pasting and thermal properties of raw corn starch-sugar mixes were analyzed before extrusion processing. The independent variables for extrusion processing included two sugar inclusion levels (2% and 10% w/w) and two screw speeds (150 and 250 rpm). The extrudates were characterized by their initial expansion ratio (IER), expansion ratio (ER), and shrinkage. ER values were high for fructose at 2% and 150 rpm and 10% glucose and sucrose extrudates at 250 rpm. The extrudates with 2% sucrose inclusion shrunk significantly higher than the control. Fourier transform infrared (FTIR) spectroscopy of the extruded blends did not indicate the presence of any new covalent bond formed between starch and sugar post-extrusion. The interactions between sugar concentration and screw speed significantly influenced extrudate expansion characteristics. Due to their thermal and plasticizing properties, sugar inclusion (glucose, fructose, sucrose, and xylose) enhanced the extrudate expansion by altering their melt viscosity. PRACTICAL APPLICATION: The findings of this study can improve the expansion characteristics of high-fiber-based extruded snacks. Ingredients high in fiber generally hinder the starch transformation during extrusion and negatively impact the expansion properties. The presence of sugar at low concentrations can improve melt properties during extrusion processing and, in turn, significantly improve the textural properties of snacks.
采用 20mm 同向旋转双螺杆挤出机制备了添加 2%和 10%（w/w）糖（果糖、葡萄糖、蔗糖和木糖）的玉米淀粉基直接膨胀产品。在挤出加工前分析了原始玉米淀粉-糖混合物的糊化和热性质。挤出加工的自变量包括两个糖含量水平（2%和 10%w/w）和两个螺杆速度（150 和 250rpm）。用初始膨胀比（IER）、膨胀比（ER）和收缩率来表征挤出物。在 2%和 150rpm 时，果糖的 ER 值较高，在 250rpm 时，10%葡萄糖和蔗糖挤出物的 ER 值较高。2%蔗糖含量的挤出物收缩率明显高于对照。挤出物的傅里叶变换红外（FTIR）光谱表明，挤出后淀粉和糖之间没有形成任何新的共价键。糖浓度和螺杆速度的相互作用显著影响挤出物的膨胀特性。由于糖的热和塑化特性，糖的添加（葡萄糖、果糖、蔗糖和木糖）通过改变其熔体粘度来提高挤出物的膨胀性。实际应用：本研究的结果可以改善高纤维基挤出小吃的膨胀特性。高纤维含量的成分通常会阻碍挤出过程中的淀粉转化，并对膨胀性能产生负面影响。低浓度的糖可以改善挤出加工过程中的熔体性能，并显著改善小吃的质构特性。
