Schmid Vera, Steck Jan, Mayer-Miebach Esther, Behsnilian Diana, Bunzel Mirko, Karbstein Heike P, Emin M Azad
Department of Food Technology and Bioprocess Engineering, Max Rubner-Institut (MRI), 76131 Karlsruhe, Germany.
Institute of Process Engineering in Life Sciences, Section I: Food Process Engineering, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.
Foods. 2021 Mar 2;10(3):518. doi: 10.3390/foods10030518.
The partial substitution of starch with dietary fiber (DF) in extruded ready-to-eat texturized (RTE) cereals has been suggested as a strategy to reduce the high glycemic index of these food products. Here, we study the impact of extrusion processing on pure chokeberry () pomace powder (CPP) rich in DF and polyphenols (PP) focusing on the content and profile of the DF fractions, stability of PP, and techno-functional properties of the extrudates. Using a co-rotating twin-screw extruder, different screw speeds were applied to CPP with different water contents (c), which resulted in specific mechanical energies (SME) in the range of 145-222 Whkg and material temperatures (T) in the range of 123-155 °C. High molecular weight soluble DF contents slightly increase with increasing thermomechanical stress up to 16.1 ± 0.8 g/100 g dm as compared to CPP (11.5 ± 1.2 g/100 g dm), but total DF (TDF) contents (58.6 ± 0.8 g/100 g dm) did not change. DF structural analysis revealed extrusion-based changes in the portions of pectic polysaccharides (type I rhamnogalacturonan) in the soluble and insoluble DF fractions. Contents of thermolabile anthocyanins decrease linearly with SME and temperature from 1.80 ± 0.09 g/100 g dm in CPP to 0.24 ± 0.06 g/100 g dm (222 Whkg, 155 °C), but phenolic acids and flavonoids appear to be largely unaffected. Resulting techno-functional (water absorption and water solubility) and physical properties related to the sensory characteristics (expansion, hardness, and color) of pure CPP extrudates support the expectation that granulated CPP extrudates may be a suitable food ingredient rich in DF and PP.
有人建议，在挤压即食组织化谷物中用膳食纤维（DF）部分替代淀粉，以此作为降低这些食品高血糖指数的一种策略。在此，我们研究挤压加工对富含DF和多酚（PP）的纯黑果腺肋花楸果渣粉（CPP）的影响，重点关注DF组分的含量和分布、PP的稳定性以及挤出物的技术功能特性。使用同向旋转双螺杆挤出机，对不同含水量（c）的CPP施加不同的螺杆转速，这导致比机械能（SME）在145 - 222 Wh/kg范围内，物料温度（T）在123 - 155°C范围内。与CPP（11.5±1.2 g/100 g dm）相比，随着热机械应力增加，高分子量可溶性DF含量略有增加，最高可达16.1±0.8 g/100 g dm，但总DF（TDF）含量（58.6±0.8 g/100 g dm）没有变化。DF结构分析揭示了可溶性和不溶性DF组分中果胶多糖（I型鼠李半乳糖醛酸聚糖）部分基于挤压的变化。热不稳定花青素的含量随SME和温度线性下降，从CPP中的1.80±0.09 g/100 g dm降至0.24±0.06 g/100 g dm（222 Wh/kg，155°C），但酚酸和黄酮类化合物似乎基本未受影响。所得的纯CPP挤出物的技术功能（吸水性和水溶性）以及与感官特性（膨胀、硬度和颜色）相关的物理性质支持了颗粒状CPP挤出物可能是一种富含DF和PP的合适食品成分的预期。
