Abstract: Freezing and thawing are two essential steps for the traditional way of ‘Ruan’er’ pear consumption. Ethephon is widely used in the acceleration of climacteric fruit ripening. This study investigated the effects of two thawing methods (room temperature air and water bath) on fruit quality and the contents of phenolic compounds in naturally ripened and ethephontreated ‘Ruan’er’ pear. The results showed that room temperature air thawing could significantly improve titratable acidity (TA), total soluble solids (TSS) content and TSS/TA ratio in naturally ripened fruit compared with water bath thawing. In addition, the fruit maintained higher VC and showed lower stone cell content during room temperature air thawing. Furthermore, room temperature air thawing reduced the TA and TSS content in ethephon-treated fruit compared with water bath thawing but had no effect on TSS/TA ratio, VC content or stone cell content. Both thawing methods had no significant effect on the total phenolic content in naturally ripened fruit but increased the total phenolic content in ethephontreated fruit. Different thawing methods had different effects on the major individual phenolic compounds with ferulic acid and chlorogenic acid being undetectable in two thawed samples. Similarly, different thawing methods had different effects on the antioxidant properties of the fruit. The antioxidant potency composite (APC) index of water bath-thawed fruit was the highest, followed in decreasing order by air thawed fruit and naturally ripened fruit. The APC index of ethephon-treated fruit was higher than that of naturally ripened fruit and the same result was observed when frozen fruits were thawed by each method.

Key words: ‘Ruan’er’ pear, thawing methods, quality, phenolic compounds, antioxidant activity