The composition of maturing Omani dates

✍ Scribed by Myhara, Robert M. (author);Karkalas, John (author);Taylor, Mark S. (author)

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 121 KB
• Volume: 79
• Category: Article
• ISSN: 0022-5142
• DOI: 10.1002/(sici)1097-0010(199908)79:11<1345::aid-jsfa366>3.0.co;2-v

✦ Synopsis

The composition of two varieties of Omani dates, fard and khalas, was determined as maturity progressed. Free sugars and dietary ®bre content were examined in detail. Highperformance liquid chromatography (HPLC) of the extracts showed that at the early green stage (Arabic kimri), dates contained small amounts of glucose and fructose. At the intermediate yellow (khalal) and red (rutab) stages, large amounts (500±565 g kg À1 dry weight) of sucrose had accumulated, but no additional glucose or fructose was detected. At the ®nal mature (tamar) stage, all sucrose was converted to glucose and fructose (b800 g kg À1 dry weight). Dietary ®bre, determined as non-starch polysaccharides (NSPs) by gas chromatography (GC), decreased from 250 g kg À1 (kimri) to 50gkg À1 (tamar) on a dry weight basis. The principal monomers of NSPs were glucose, galactose, xylose, mannose, arabinose and rhamnose. On a dry weight basis, pectin, protein and ash contents decreased as the dates matured. On a fresh weight basis, changes in NSPs, pectin, protein and ash could be attributed to loss of moisture and the accumulation of sucrose initially, or of invert sugar later as maturation progressed.