Abstract:

【Objective】 Fruit flavor compounds including volatile compounds, sugars and organic acids of five mid-season apple cultivars were analyzed and the formation of these cultivars’ flavor quality was studied. The results could offer the reference for the utilization in production of the mid-season apple cultivars and provide a theoretical basis for the mid-season apple breeding by formulating the evaluation index system. 【Method】 The volatile compounds, sugars, organic acids of the fruits of tested cultivars were identified and quantified using static headspace and gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). 【Result】 The results showed that forty volatile compounds were detected from the samples of testing cultivars, and the main compounds were alcohols, aldehydes and esters. There were eleven characteristic compounds (CICs) in Royal Gala, nine in Mollies Delicious, eleven in NY543, seven in Meilong and seven in Qiukouhong. These CICs smelled differently. Three sugars and six organic acids were detected from the samples of five cultivars. Fructose was the most dominant sugar, followed by glucose and sucrose, while malic acid was the principal organic acid, followed by succinic, oxalic, acetic, citric and tartaric acid. A great difference was found in the contents of sugars and organic acids among five apple cultivars, whereas their kinds were similar. Fructose, glucose and sucrose contributed to the sweetness taste of fruit in common, while malic acid contributed to sourness. The fruits of tested cultivars were different in the content of total sugars, sugars/malic acid ratio and taste evaluation. Such difference in taste evaluation accorded with the differences in total sugar content and sugars/malic acid ratio.【Conclusion】 The odour of different CICs formed respective aroma of the tested cultivars. Three sugars and malic acid were the factors which influenced the fruit sweetness and sourness of five cultivars. Total sugars and sugars/malic acid ratio could be used in the taste evaluation criteria of the five mid-season apple cultivars.

Key words: apple, mid-season apple cultivars, flavor compounds, flavor quality