流变仪原位检测技术在饮料网络结构评价中的应用

Application of Technology Combined Rheometer and In-Situ Determination on Network Structure Evaluation of Beverages

建立了流变仪原位检测技术表征饮料网络结构强弱的方法,并研究其在乳酸菌饮品与红豆薏米饮品中的应用。采用浆式转子缓慢伸入原包装样品,在不破坏样品结构的基础上应用高级旋转流变仪测定饮料的频率扫描。实验结果表明,对于乳酸菌饮品,弹性模量可以区分体系网络结构的大小,也可区分储存温度与储存时间引起的饮料上下部网络结构的强弱差异,表现为下部强于上部,室温组强于37℃组强于55℃组。对于增稠剂主要为微晶纤维素钠与卡拉胶的红豆薏米饮品,弹性模量与频率的曲线斜率大小可以评价其网络结构的强弱,表现为斜率小于0.05时弱凝胶严重,0.05~0.09时弱凝胶一般严重,0.09~0.11时弱凝胶轻微,大于0.11时无弱凝胶;另外,上部比下部网络结构更强。因此,流变仪原位检测技术避免了对样品结构的破坏,可以评价饮料网络结构的强弱,指导饮料的研发与生产。

The method using the technology combined rheometer and in-situ determination to characterize the network structure strength of beverage was established,which was applied to evaluate the lactic acid bacteria beverage and the protein beverage with red bean and coix seed in this study. The rotor was immersed slowly into the sample in original packaging,followed by the experiments of frequency sweep on the beverage with advanced rotational rheometer not destroying the sample structure. The experimental results showed that for the lactic acid bacteria beverage,elastic modulus could distinguish the network structure. Morevoer,it could distinguish effects of the storage temperature and storage time on the network structure. The results were as follows： the lower part 〉upper part,room temperature 〉37 ℃ 〉55℃. The protein beverage with red bean and coix seed contained sodium microcrystalline cellulose and carrageenan as the thickeners. The slope of the dependence of elastic modulus on the frequency could evaluate the strength of network structure. The weak gel was serious,generally serious,slight,and none when slope was 〈0. 05,0. 05 ~ 0. 09,0. 09 ~ 0. 11 and 〉0. 11 respectively. Moreover,the upper part had a more stronger network structure than the lower part. In conclusion,the technology combined rheometer and in-situ determination could evaluate the network structure strength of beverages avoiding the damage of the sample structure and provide guidance on the RD and production of beverages.