Ek Pichmony, Gu Bon-Jae, Richter Jana K, Dey Debomitra, Saunders Steven R, Ganjyal Girish M
School of Food Science, Washington State University, Pullman, Washington, USA.
Faculty of Chemical and Food Engineering, Institute of Technology of Cambodia, Phnom Penh, Cambodia.
J Food Sci. 2023 Oct;88(10):4156-4168. doi: 10.1111/1750-3841.16742. Epub 2023 Aug 25.
Improving total dietary fiber content while maintaining the texture/expansion of extruded products is a challenge. Pectin has a dual function; it is a source of dietary fiber and it also functions as a hydrocolloid, which could improve the texture of high-fiber extruded foods. The objective of this study was to evaluate the impacts of pectin types from citrus peel on the expansion characteristics of starch-cellulose extrudates. High and low methoxyl pectin (HMP and LMP) was added to the starch-cellulose mixtures and extruded using a twin-screw extruder. The pasting properties of raw mixtures, extrusion properties, microstructure, and dietary fiber contents of the extrudates were studied. The inclusion of HMP in raw material improved the peak viscosity (629.7 ± 8.1 to 754.7 ± 80.1 mPa s) and maintained the final viscosity compared to the control (starch-cellulose mixture alone), unlike LMP. HMP relatively maintained the extrusion process parameters such as torque, back pressure, and specific mechanical energy as the control. Interestingly, the addition of 7% of HMP had a similar expansion ratio (3.41 ± 0.08 to 2.35 ± 0.06) compared to the control (3.46 ± 0.08 to 2.32 ± 0.09) under the extrusion conditions studied. The total dietary fiber content improved from 12.22 ± 0.01% to 18.26 ± 0.63% (w/w). HMP maintained the expansion characteristic of starch-cellulose extrudates and improved its total dietary fiber content relative to LMP. Adding HMP to the mixtures improved the extensibility of the melt, favoring bubble growth and expansion of the starch-cellulose extrudates. Fourier transform infrared spectroscopy data suggested that there could be intermolecular interactions between starch, cellulose, and pectin, but the nature of these interactions needs further investigation. PRACTICAL APPLICATION: The study provides practical information on the influence of the addition of high and low methoxyl pectin on starch-cellulose extrudates. The results can help the industry to produce snack products that are more nutritious but are still well accepted by the consumers.
在保持挤压产品质地/膨胀性的同时提高总膳食纤维含量是一项挑战。果胶具有双重功能；它是膳食纤维的来源，还可作为水胶体，这可能会改善高纤维挤压食品的质地。本研究的目的是评估柑橘皮果胶类型对淀粉 - 纤维素挤出物膨胀特性的影响。将高甲氧基果胶和低甲氧基果胶（HMP和LMP）添加到淀粉 - 纤维素混合物中，并用双螺杆挤出机进行挤压。研究了原料混合物的糊化特性、挤压特性、微观结构和挤出物的膳食纤维含量。与对照（仅淀粉 - 纤维素混合物）相比，在原料中加入HMP可提高峰值粘度（从629.7±8.1至754.7±80.1 mPa·s）并保持最终粘度，而LMP则不然。HMP与对照相比相对保持了挤压工艺参数，如扭矩、背压和比机械能。有趣的是，在所研究的挤压条件下，添加7%的HMP与对照（3.46±0.08至2.32±0.09）相比具有相似的膨胀比（3.41±0.08至2.35±0.06）。总膳食纤维含量从12.22±0.01%提高到18.26±0.63%（w/w）。相对于LMP，HMP保持了淀粉 - 纤维素挤出物的膨胀特性并提高了其总膳食纤维含量。向混合物中添加HMP改善了熔体的延展性，有利于淀粉 - 纤维素挤出物的气泡生长和膨胀。傅里叶变换红外光谱数据表明淀粉、纤维素和果胶之间可能存在分子间相互作用，但这些相互作用的性质需要进一步研究。实际应用：该研究提供了关于添加高甲氧基和低甲氧基果胶对淀粉 - 纤维素挤出物影响的实用信息。结果可帮助食品行业生产更营养但仍受消费者欢迎的休闲食品。
