| dc.description.abstract | A novel on-package color indicator has been
fabricated based on bromophenol blue, and tests have been
conducted to assess the freshness of guava (Psidium
guajava L.). Bromophenol blue (BPB) was immobilized
onto bacterial cellulose membrane via absorption method.
The BPB/cellulose membrane as color indicator works
based on pH decrease as the volatile organic compounds
(e.g. acetic acid), produced gradually in the package
headspace during developing of guava. Subsequently the
color of the indicator will change from blue to green for
over-ripe indication, which can be visible to the naked eye.
The results showed that the color indicator could be used to
determine the state of freshness of the guava at ambient
condition (28–30 C). The color change of the indicators
reflects the pH of headspace of the guava packaging. Furthermore,
it also in similar trends to the change of several
parameters (soluble solids content, texture and sensory
evaluation) that normally used to characterize the freshness
of guava. Therefore, the indicator can be used for real time
visual monitoring of freshness state of packaged guavas. | en_US |
