Parker M L, Ng A, Smith A C, Waldron K W
Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, United Kingdom.
J Agric Food Chem. 2000 Dec;48(12):6284-91. doi: 10.1021/jf0004199.
Chufas (Cyperus esculentus) are edible tubers that, like Chinese waterchestnut (CWC), are very crisp when raw and do not soften when cooked. The present study compares the mechanical properties of chufas with those of potato and CWC in relation to the carbohydrate and phenolic compositions of the cell walls. The cutting toughness of raw chufa was higher than that of raw CWC and potato; its value decreased on boiling, as also observed with CWC, but remained over twice that of raw potato. Chufa cell walls were rich in xylose, arabinose, glucose, uronic acid, and galactose, with minor quantities of mannose. The cell walls of the parenchyma exhibited a uniform pH-dependent autofluorescence indicating the presence of cinnamic acid derivatives. Analysis of these revealed that peeled tuber cell walls are rich in ferulic acid, whereas p-coumaric acid dominates the monomeric phenol fraction of the skin. Cell wall material from both skin and peeled tubers contains a significant amount of different diferulic acids ( approximately 20% of the wall ferulic acid), consisting mainly of the 8-O-4'-, 8-5'-, and 5-5'-dimers. These are potentially available to form thermally stable cross-links between polysaccharides within the wall and between cells. This may confer thermal stability of texture.
荸荠（莎草科荸荠属）是可食用的块茎，与中国菱角一样，生时非常脆，煮熟后也不会变软。本研究比较了荸荠与马铃薯和中国菱角在细胞壁碳水化合物和酚类成分方面的机械性能。生荸荠的切割韧性高于生中国菱角和马铃薯；与中国菱角一样，其值在煮沸后降低，但仍为生马铃薯的两倍多。荸荠细胞壁富含木糖、阿拉伯糖、葡萄糖、糖醛酸和半乳糖，含有少量甘露糖。薄壁组织的细胞壁表现出均匀的pH依赖性自发荧光，表明存在肉桂酸衍生物。对这些成分的分析表明，去皮块茎细胞壁富含阿魏酸，而对香豆酸则在表皮的单体酚类成分中占主导地位。来自表皮和去皮块茎的细胞壁材料含有大量不同的二阿魏酸（约占细胞壁阿魏酸的20%），主要由8-O-4'、8-5'和5-5'二聚体组成。这些物质有可能在细胞壁内的多糖之间以及细胞之间形成热稳定的交联。这可能赋予质地热稳定性。
