Day Li, Swanson Barry G
CSIRO Animal, Food and Health Sciences, Werribee, VIC 3030, Australia.
School of Food Science, Washington State Univ., Pullman, WA 00164-6376, USA.
Compr Rev Food Sci Food Saf. 2013 Sep;12(5):546-564. doi: 10.1111/1541-4337.12023.
Fortification of extrusion feed formulations with proteins from selected sources will improve the health-promoting quality of snack and breakfast foods. Molecular interactions among proteins, starch, lipids, water, and other constituents in the extrusion "melt" are the basis for extrudate appearance as well as textural, sensory, and physical properties. Covalent disulfide and sulfhydryl bonding as well as electrostatic, hydrogen, and hydrophobic affinity developing among molecules during extrusion determine extrudate sensory quality, digestibility, and nutrient availability. Extrudate quality is dependent on the physical profile of the feed material from particle size to moisture concentration, the mechanical profile of the twin-screw extruder from screw speed to die aperture, and the temperature, pressure, and shear leading to specific mechanical energy delivered in the extruder. Methods to assess extrudate physical and sensory quality are presented. Protein concentration, feed moisture, and extrusion temperatures are most important to expansion, density, and texture of extrudates. Fortification with whey and wheat proteins results in acceptable extrusion of snack and breakfast foods. Extrusion generally improves protein quality and digestibility while retaining active nutrients.
用选定来源的蛋白质强化挤压饲料配方，将提高休闲食品和早餐食品的健康促进品质。挤压“熔体”中蛋白质、淀粉、脂质、水和其他成分之间的分子相互作用是挤出物外观以及质地、感官和物理性质的基础。挤压过程中分子间形成的共价二硫键和巯基键以及静电、氢键和疏水亲和力决定了挤出物的感官品质、消化率和营养利用率。挤出物质量取决于从颗粒大小到水分浓度的进料材料物理特性、从螺杆速度到模孔的双螺杆挤出机机械特性，以及导致挤出机中传递特定机械能的温度、压力和剪切力。介绍了评估挤出物物理和感官品质的方法。蛋白质浓度、进料水分和挤压温度对挤出物的膨胀、密度和质地最为重要。用乳清蛋白和小麦蛋白强化可使休闲食品和早餐食品获得可接受的挤压效果。挤压通常会提高蛋白质质量和消化率，同时保留活性营养成分。
