Use of natural antimicrobials and high pressure homogenization to control the growth of Saccharomyces bayanus in apple juice

This paper proposes a combined approach based on homogenization and antimicrobial compounds for the inhibition of Saccharomyces bayanus in apple juice. In a first phase, the experiments were performed in a laboratory medium combining homogenization (0-60 MPa), limonene (0-1800 ppm) and citrus extract (0-3 ppm) by a mixture design. Thus, two combinations (homogenization at 20 MPa + 900 ppm of limonene and homogenization at 20 MPa + 2 ppm of citrus extract) were chosen for validation in apple juice. Juice was inoculated at two different levels (2 and 4 log(10) cfu/ml), supplemented with the antimicrobials, homogenized and stored at 25 degrees C for 8 days for an accelerated shelf life test. Just after homogenization/preparation, juices were analyzed by a consumer test, to assess the purchase intent of 32 consumers. Concerning microbiological data, homogenization reduced by 2-4 log(10) cfu/ml colony count of S. bayanus, whereas citrus extract was able to control yeast growth for 4-8 days. Finally, consumer test pointed out panel acceptability for homogenized juice, containing citrus extract; the use of limonene was not advisable for its strong organoleptic impact. (C) 2011 Elsevier Ltd. All rights reserved.