不同氧化度的魔芋葡甘露聚糖对凝固型酸奶品质的影响

Effect of Konjac Glucomannan with Different Oxidizing Degrees on the Quality of Set-type Yoghurt

“健康低脂”的食品理念近来广受大众欢迎。为改善低脂凝固型酸奶的凝胶强度低等问题,向酸奶中添加氧化魔芋葡甘露聚糖(Oxidized konjac glucomannan,OKGM)作为脂肪替代物,通过对酸奶理化性质、质构、流变学特性和微观结构等指标的分析,探究不同氧化度OKGM对酸奶品质的影响。结果表明,含高氧化度的OKGM(OK-60、OK-90、OK-120)的酸奶与未添加OKGM的酸奶相比,硬度从375.90 g提高至436.67 g,持水力从28.03%提高至31.89%,同时,能够提高流变学特性中的表观黏度和粘弹性。扫描电镜和激光共聚焦结果显示,高氧化度的OKGM缩小了酸奶凝胶结构间的孔隙,提高了酪蛋白胶束间的聚集,使其平均粒径从88.27 nm增加到125.33 nm。然而,天然的魔芋葡甘露聚糖(Konjac glucomannan,KGM)和低氧化度的OKGM(OK-30)则会降低酸奶的质构、表观黏度和粘弹性,破坏酸奶的凝胶结构,导致其稳定性下降。感官评价结果显示,高氧化度的OKGM使酸奶更有光泽,体系更加均匀,且在滋味上更具优势,这也为健康低脂酸奶的开发奠定了理论基础。

The food concept of"healthy low-fat"had attracted significant public attention in recent years.Oxidized konjac glucomannan(OKGM)was introduced as a fat replacer to address the issue of low gel strength in low-fat yoghurt.The effects of different oxidation degrees of OKGM on the quality of yoghurt were investigated by analyzing the physicochemical properties,texture,rheological properties and microstructure of yoghurt.The research demonstrated that yoghurt containing high oxidation degrees of OKGM(OK-60,OK-90,OK-120)increased the hardness from 375.90 g to 436.67 g and the water holding capacity from 28.03%to 31.89%compared to yoghurt without added OKGM.In addition,it improved the rheological properties of yoghurt including apparent viscosity and viscoelasticity.The results of scanning electron microscopy and confocal laser microscopy revealed that high oxidation degrees of OKGM reduced integral pores in yoghurt,promoted casein micelles aggregation,and increased average particle size from 88.27 nm to 125.33 nm.In contrast,natural konjac glucomannan(KGM)and lower levels of OKGM oxidation(OK-30)reduced texture,apparent viscosity,and viscoelasticity of the yoghurt,disrupted yoghurt gel structure and compromised its stability.The results of sensory evaluation showed that high oxidation levels improved the glossiness,uniformity,and overall taste of yoghurt,providing a theoretical basis for the development of high-quality,low-fat,and healthy yoghurt products.