Kim Sung-Gun, Yoo Byoungseung
Department of Food Science and Biotechnology, Dongguk University, Seoul, Korea.
Int J Lang Commun Disord. 2015 May-Jun;50(3):397-402. doi: 10.1111/1460-6984.12141. Epub 2014 Dec 3.
Although extensive literature is available on the viscosity of thickened beverages with food thickeners, no attempt has been made to study the effect of setting time on the viscosity of pudding-like cold-thickened beverages with xanthan gum (XG)-based thickeners by using a rheometer. In particular, it is of considerable practical importance to investigate the effect of setting time on their viscosity at 5°C because some cold-thickened beverages will be prepared in the kitchen in bulk and stored at 5°C before serving or consuming rather than serving immediately upon mixing with thickeners.
To examine the effect of different setting times (15-120 min) on the viscosity of cold-thickened beverages prepared with various XG-based food thickeners, and also to compare the viscosity differences among the various cold beverages and XG-based food thickeners in beverage-thickener mixture systems.
METHODS & PROCEDURES: Four commercially available XG-based food thickeners (A-D) and three cold beverages (water, orange juice and milk) were used for the preparation of cold-thickened beverages. The thickened sample was portioned into six samples for the designated setting times and then stored at 5°C over setting time. Their apparent viscosity (η(a,50)) at 50 s(-1) was measured using a rheometer.
OUTCOMES & RESULTS: The largest increases in η(a,50) values for thickened beverages, except for water, were observed at 15 min (p < 0.05), showing a pudding-like fluid, and at longer time periods their η(a,50) values gradually increased or were constant with an increase in setting time. The percentage increase in viscosity values at different setting times (15-120 min) as compared with the control (0 min) was less pronounced in the thickened orange juice and milk samples with thickener A over setting time, indicating that the thickened beverages with thickener A had more stable structure compared with those with other thickeners (B-D) over time. Statistical analysis showed that changes in the viscosity of cold-thickened beverages over setting time are greatly influenced by the type of beverages and thickeners.
CONCLUSIONS & IMPLICATIONS: Cold-thickened beverages should be carefully prepared with instant commercial XG-based food thickeners because they produced different thickening patterns over setting time which clinicians must consider for a safe and easy swallowing. The information presented in this study will provide both clinicians and patients with additional knowledge to prepare cold-thickened beverages with the corrected viscosity for safe swallowing.
尽管关于使用食品增稠剂的增稠饮料的粘度已有大量文献，但尚未有人尝试使用流变仪研究凝固时间对基于黄原胶（XG）的增稠剂制备的布丁状冷增稠饮料粘度的影响。特别是，研究凝固时间对其在5°C时粘度的影响具有相当重要的实际意义，因为一些冷增稠饮料会在厨房大量制备并在5°C下储存，直到上桌或食用，而不是在与增稠剂混合后立即上桌。
研究不同凝固时间（15 - 120分钟）对使用各种基于XG的食品增稠剂制备的冷增稠饮料粘度的影响，并比较饮料 - 增稠剂混合体系中各种冷饮料和基于XG的食品增稠剂之间的粘度差异。
使用四种市售的基于XG的食品增稠剂（A - D）和三种冷饮料（水、橙汁和牛奶）制备冷增稠饮料。将增稠后的样品分成六个样本，设定指定的凝固时间，然后在5°C下储存至凝固时间结束。使用流变仪测量它们在50 s⁻¹时的表观粘度（η(a,50)）。
除水之外，增稠饮料的η(a,50)值在15分钟时出现最大增幅（p < 0.05），呈现出布丁状流体，在更长时间段内，其η(a,50)值随着凝固时间的增加逐渐上升或保持恒定。与对照（0分钟）相比，在凝固时间内，增稠剂A增稠的橙汁和牛奶样品在不同凝固时间（15 - 120分钟）的粘度增加值百分比不太明显，这表明随着时间推移，与其他增稠剂（B - D）相比，增稠剂A增稠的饮料具有更稳定的结构。统计分析表明，冷增稠饮料粘度随凝固时间的变化受饮料和增稠剂类型的显著影响。
冷增稠饮料应使用即食型市售基于XG的食品增稠剂精心制备，因为它们在凝固时间内产生不同的增稠模式，临床医生在确保安全和易于吞咽时必须考虑这一点。本研究提供的信息将为临床医生和患者提供更多知识，以便制备具有正确粘度的冷增稠饮料以确保安全吞咽。
