仙人掌（Opuntia ficus-indica）刺梨经对流干燥后提取物的抗氧化性能研究。
Study of the antioxidant properties of extracts obtained from nopal cactus (Opuntia ficus-indica) cladodes after convective drying.
机构信息
Departamento de Ingeniería Química, Facultad de Química, Edificio 'E', Lab-213, Universidad Nacional Autónoma de México (UNAM), 04510 México, DF, Mexico.
出版信息
J Sci Food Agric. 2011 Apr;91(6):1001-5. doi: 10.1002/jsfa.4271. Epub 2011 Feb 2.
BACKGROUND
The process of convective drying was evaluated in terms of the bioactive compounds contained in nopal samples before and after dehydration. Total polyphenol, flavonoid, flavonol, carotene and ascorbic acid contents were determined in undehydrated and dehydrated samples. Two drying temperatures (45 and 65 °C) and two air flow rates (3 and 5 m s(-1) ) were evaluated. The rheology of samples under the best drying conditions was also studied, since it provides important information regarding processing (mixing, flow processing) as well as the sensory attributes (texture) of rehydrated samples.
RESULTS
Non-Newtonian shear-thinning behaviour was observed for samples dried at 45 °C, while samples dried at 65 °C showed shear-thickening behaviour, possibly caused by thermal chain scission of high-molecular-weight components.
CONCLUSION
The best conditions for bioactive compound preservation were a drying temperature of 45 °C and an air flow rate of 3 m s(-1) , resulting in 40.97 g phenols, 23.41 g flavonoids, 0.543 g β-carotene and 0.2815 g ascorbic acid kg(-1) sample as shown in table 3.
背景
在对仙人掌样本进行脱水前后，评估了其所含的生物活性化合物的对流干燥过程。在未脱水和脱水样本中测定了总多酚、类黄酮、黄酮醇、类胡萝卜素和抗坏血酸的含量。评估了两种干燥温度（45 和 65°C）和两种空气流速（3 和 5 m s(-1) ）。还研究了最佳干燥条件下的样本流变学，因为它提供了有关加工（混合、流动加工）以及复水样本感官属性（质地）的重要信息。
结果
在 45°C 下干燥的样品表现出非牛顿剪切稀化行为，而在 65°C 下干燥的样品表现出剪切增稠行为，这可能是由于高分子量成分的热链断裂引起的。
结论
生物活性化合物保存的最佳条件是干燥温度为 45°C，空气流速为 3 m s(-1) ，结果如表 3 所示，样品中含有 40.97 g 酚类、23.41 g 类黄酮、0.543 g β-胡萝卜素和 0.2815 g 抗坏血酸。
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