机械加工对燕麦β-葡聚糖理化特性及体外发酵的影响

Effects of mechanical processing on the physicochemical properties of oatβ-glucan and its in vitro fermentation

目的:研究机械加工对燕麦β-葡聚糖理化特性和体外发酵特性的影响。方法:通过钢切、压片、研磨等机械加工方式分别制得燕麦粗粒、燕麦片、燕麦粉,采用扫描电镜观察微观结构,测定燕麦β-葡聚糖的含量、溶出率和相对分子质量,体外模拟结肠环境进行燕麦发酵。结果:燕麦粗粒的β-葡聚糖总含量和溶出率均高于燕麦米,而燕麦片和燕麦粉的β-葡聚糖总含量低于燕麦米,但溶出率高于燕麦米。燕麦米具有较低的发酵速率,产酸产气速率明显低于燕麦粗粒、燕麦片、燕麦粉,虽然发酵产生的总短链脂肪酸含量最低,但丙酸和丁酸含量显著高于其他3组。结论:机械加工可以通过改变燕麦细胞壁结构完整性及β-葡聚糖的含量和溶出率,进而影响其体外发酵特性,适度加工有助于燕麦健康功效的发挥。

Objective:To evaluate the effects of mechanical processing on the physicochemical properties of oatβ-glucan and its in vitro fermentation.Methods:Oat coarse grains,oat flakes,and oat flour were respectively produced through mechanical progressing methods such as steel cutting,table pressing,and grinding.Then,scanning electron microscopy was used to observe the microstructure,the content,dissolution rate and relative molecular weight of oatβ-glucan were determined,and the colon environment was simulated in vitro for fermentation.Results:The totalβ-glucan content and dissolution rate of steel-cutting oat were higher than those of untreated sample.The totalβ-glucan content of oat flake and oat flour were lower than untreated oat,but the dissolution rate was higher than it.Untreated oat showed a lower fermentation rate,with a significantly lower acid and gas production rate than those of steel-cutting oat,oat flake,and oat flour.The total short chain fatty acid content of untreated oat produced by fermentation was the lowest,but the content of propionic acid and butyric acid was significantly higher than the other three groups.Conclusion:Mechanical progressing can affect the in vitro fermentation characteristics of oats by altering the integrity of their cell wall structure,as well as the content and dissolution rate ofβ-glucan.Moderate processing can contribute to the health benefits of oats.