Kohyama Noriko, Fujita Masaya, Ono Hiroshi, Ohnishi-Kameyama Mayumi, Matsunaka Hitoshi, Takayama Toshiyuki, Murata Masatsune
National Institute of Crop Science, NARO, Tsukuba, Ibaraki 305-8518, Japan.
J Agric Food Chem. 2009 Jul 22;57(14):6402-7. doi: 10.1021/jf901944m.
Barley grain products undergo browning when cooked. To evaluate effects of phenolic compounds on browning, various amounts of (+)-catechin, proanthocyanidins, or related phenolic compounds were added to aqueous barley extracts or barley pastes, which were heated at 90 degrees C for 1 or 2 h, respectively. In barley extract, (+)-catechin, procyanidin B3 (PCB3), prodelphinidin B3 (PDB3), and a trimer of gallocatechin-gallocatechin-catechin (PDT1) dose-dependently elevated absorbance at 420 nm after heating. PDB3 caused browning faster than PCB3 and (+)-catechin. In barley paste, PDB3 and PDT1 decreased the L* value and increased the a* and b* values of the paste dose-dependently after heating and PCB3 and (+)-catechin did so to a lesser extent. Caffeic acid promoted the browning in both of the extract and paste, while protocatechuic acid, eriodictyol, and (+)-taxifolin promoted it in the extract and myricetin and quercetin promoted it in the paste. Compounds promoting browning have catechol or pyrogallol structures in common.
大麦谷物制品在烹饪时会发生褐变。为了评估酚类化合物对褐变的影响，将不同量的（+）-儿茶素、原花青素或相关酚类化合物添加到大麦水提取物或大麦糊中，分别在90℃下加热1小时或2小时。在大麦提取物中，加热后（+）-儿茶素、原花青素B3（PCB3）、原花青定B3（PDB3）和表儿茶素-表儿茶素-儿茶素三聚体（PDT1）在420nm处的吸光度呈剂量依赖性升高。PDB3导致褐变的速度比PCB3和（+）-儿茶素快。在大麦糊中，加热后PDB3和PDT1剂量依赖性地降低了糊的L值，增加了a和b*值，而PCB3和（+）-儿茶素的作用程度较小。咖啡酸在提取物和糊中均促进褐变，而原儿茶酸、圣草酚和（+）-紫杉叶素在提取物中促进褐变，杨梅素和槲皮素在糊中促进褐变。促进褐变的化合物具有共同的儿茶酚或邻苯三酚结构。
