Comparison of Enzymic, Gas-Liquid Chromatographic, and High Performance Liquid Chromatographic Methods for Determining Sugars and Organic Acids in Strawberries at Three Stages of Maturity

Abstract

Free sugars and major nonvolatile organic acids present in strawberries at 3 degrees of ripeness were determined by 3 analytical methods: enzymic, gasliquid chromatographic, and high performance liquid chromatographic. Results showed that variability in sugar composition due to both degree of ripeness and method of analysis was greater for sucrose than for glucose and fructose. Sucrose was almost completely hydrolyzed in the overripe fruit. Acid results showed that there was little variation in citric acid levels due to ripeness or method of analysis; malic acid, however, decreased greatly in overripe fruit. Malic acid also showed high variability due to method of analysis. The glucose:fructose ratios for the underripe, ripe, and overripe fruit were 0.86,0.92, and 0.60, respectively. The citric:malic ratios were 1.58, 2.39, and 14.86 for the underripe, ripe, and overripe stages, respectively.