Aroma components at various stages of litchi juice processing

BACKGROUND: Considering the importance of flavour on the quality of litchi juice, a study was conducted on how processing and operating stages influence the aroma components of clear litchi juice during processing. RESULTS: The aroma fractions isolated by solid‐phase micro‐extraction were analysed by capillary gas chromatography–mass spectrometry. According to statistical analyses, the amount of total and seven characteristic aroma compounds (geraniol, citronellol, phenylethyl alcohol, D ‐limonene, nonanal, geranial and linalool) increased significantly after enzyme hydrolysis, but decreased significantly during the process of enzyme inactivation, ultra‐filtration and sterilisation. CONCLUSION: The aromatic fraction of litchi juice decreased greatly during processing. The major losses in aromatic composition of clear litchi juice were related to the ultra‐filtration and sterilisation processes. With regard to the retention of aroma, an ultra‐filtration membrane with a larger pore size is better than a membrane with a smaller pore size, and a high‐voltage pulsed electric field was better than thermal sterilisation. Copyright © 2009 Society of Chemical Industry