LAUSR

ABSTRACT This study characterized the effect of thermal sterilization on the volatiles in flat peach juice. In three independent trials, juice samples prepared with flat peaches from Shihezi, Xinjiang, China were divided into groups sterilized at 65, 75, and 85°C for 30 min. The chemical compositions were identified by gas chromatography–mass spectrometry combined with headspace solid-phase microextraction and analyzed by hierarchical clustering and principal component analysis. Fourteen volatiles (seven esters, four alcohols, two aldehydes, and one ketone) were identified as characteristic in fresh peach juice. Esters of thermally treated samples were significantly decreased by threefold (P < 0.001) compared to fresh peach juice (69.19%). At 75 and 85°C, only 21.00 and 21.40% of the esters were retained in the juice. Alkanes increased from zero to 22.80 to 30.20%. The ketones increased from 0.60 to 6.50% and 8.60%. The changes in esters, alkanes and ketones were the main factors that caused the differences in aroma and flavor between the fresh and thermal-sterilized juices. Principal component analysis showed that these 14 characteristic volatiles were strongly influenced by temperature changes. In particular, changes in alcohols were highly correlated with thermal processing. These results provide a reference for peach juice processing.