Department of Food Science and Technology, Faculty of Nutrition Science, Food Science and Technology/National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Food Science, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
Department of Food Science and Technology, Faculty of Nutrition Science, Food Science and Technology/National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Food Chem. 2018 Apr 15;245:958-965. doi: 10.1016/j.foodchem.2017.11.077. Epub 2017 Nov 22.
Tomato juice and paste are special type of dispersions, composed of suspended particles (pulp) dispersed in a colloidal liquid medium (serum). The bright red appearance of soluble solid separated by high speed centrifugation denoted the presence of lycopene in this fraction. Since lycopene is a hydrophobic compound it is not expected to appear in the water soluble fraction. HPLC analysis indicated presence of substantial amount of lycopene in soluble fraction which was confirmed by the appearance of lycopene crystals when observed under Transmission Electron Microscope (TEM). Considerable amount of pectin in the soluble fraction led to hypothesis that pectin facilitated the formation of hydrocolloidal system of suspended lycopene during processing. Enzyme treatment confirmed this hypothesis when pectinase effectively disrupted colloidal system and precipitated lycopene. Necessity of the divalent ions to retain the suspension signified the electrostatic interactions in the matrix surrounding lycopene crystals.
番茄酱和番茄糊是一种特殊的分散体系，由悬浮颗粒（果肉）分散在胶体液相（血清）中组成。高速离心分离出的可溶性固体的亮红色表示该部分存在番茄红素。由于番茄红素是一种疏水化合物，预计它不会出现在水溶性部分。高效液相色谱分析表明，可溶性部分中存在大量的番茄红素，这一点通过在透射电子显微镜（TEM）下观察到番茄红素晶体的出现得到了证实。可溶性部分中大量的果胶导致了这样一种假设，即在加工过程中果胶有助于形成悬浮番茄红素的水胶体系统。当果胶酶有效地破坏胶体系统并沉淀番茄红素时，酶处理证实了这一假设。二价离子保留悬浮液的必要性表明了围绕番茄红素晶体的基质中的静电相互作用。
