低GI挤压重组米的制备及其品质特性比较

Preparation and Characterization of Extruded Rice with a Low Glycemic Index

大米是我国居民的日常主食,但其高血糖生成指数(Glycemic Index,GI)使得肥胖及高血糖人群望而却步。为解决该问题,该文采用挤压工艺制备外观品质和食用口感俱佳的低GI重组米,以大米粉为主基料,通过将桑叶提取物与抗性淀粉复配作为重组米中降低GI值的主要功能成分,并通过添加单甘酯、燕麦麸皮以及大豆多糖对重组米的品质特性进行调节。研究发现,添加了桑叶提取物和抗性淀粉的重组米的葡萄糖释放速率(≤0.025 min^(-1))显著低于天然大米(0.060 min-1),预测血糖生成指数(Expected Glycemic Index,eGI)≤46.93。重组米的结构均紧凑致密,颗粒完整性良好。单甘酯和燕麦麸皮的添加可以增强重组米的硬度,降低粘附性;而大豆多糖的添加则使得重组米外观形貌较好,且米饭口感更为软糯。基于感官评定,添加了大豆多糖并以桑叶提取物与抗性淀粉为功能成分的重组米的总体评价较高,其感官特性与天然大米更为相近,因此该制备方案较佳,更适于制备低GI重组米。

Rice is the primary staple food for people in China.However,people with obesity and the diabetes are discouraged from consuming rice due to its high glycemic index(GI).A low-GI extruded rice was prepared using the extrusion technique.The rice had good appearance,quality,and taste.Extrusion technique was employed to ensure that the extruded rice closely resembles natural rice.Rice flour was used as the main material,and a mixture of mulberry leaf extract and resistant starch was added for their bioactive function of GI reduction.Monoglycerides,oat bran,and soybean polysaccharides were added to modify the properties of the extruded rice.The glucose release rate during in vitro digestion significantly decreased(from 0.060 to 0.025 min^(-1))when the mixture of mulberry leaf extract and resistant starch was added,and the estimated GIs for the finished extruded rice samples were≤46.93.Moreover,their structure was compact and tightly packed and their morphology was intact.The addition of monoglycerides and oat bran enhanced the hardness of the extruded rice and reduced its adherence,whereas the addition of soy polysaccharides improved its appearance and made the extruded rice softer and more glutinous.The total sensory evaluation score for the extruded rice prepared with soybean polysaccharides,mulberry leaf extract,and resistant starch as the functional components was the highest,and its sensory characteristics were closest to that of natural rice amongst the modified,low-GI versions.This suggests that this preparation method is superior and more suitable for low-GI extruded rice.