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FSB1 – 2004
Food Science and Biotechnology in Developing Countries
We used two varieties of fresh sliced fruit: grafted and creole.
As inhibitors were used solutions: salt (9%), sugar (14%), citric acid (0.5% and 1%), ascorbic acid
(0.5% and 1%) and its combinations. The fruit was submerged in the solutions by 50 min. The
peroxidase and catalase activities were evaluated by the method proposed in (2 and 3), in addition to
color change in the exposition to air for 24 and 48 h.
The positive control was fruit submerged in distilled water.
The negative control was sterilized fruit.
Statistical analysis
The experimental data were analyzed statistically by analysis of variance, for statistical significance
(α= 0.050) using LSD test (Statistical Analysis System, SAS).
Results and discussion
Table 1 shows the results from color change at 24 hours in exposition to air, peroxidase and catalase
tests.
Table 1. Color change, peroxidase and catalase probe.
PEROXIDASE CATALASE
Color change at 24 hr in
exposition to air
AGENT CREOLE GRAFTED CREOLE GRAFTED CREOLE GRAFTED
Salt 9% + + + + - -
Sugar 14% + + + + + +
Salt-sugar - + + + - -
Salt-sugar- ascorbic - - + - - -
Salt-sugar- citric - - + + - -
Sugar - citric + + + + + +
Sugar - ascorbic + - - + + +
Salt- ascorbic + + + + - -
Salt - cítric - - + + - -
Salt-sugar-citric 0.5%-ascorbic
0.5%
- - + + - -
Salt/sugar-citric 1%-ascorbic acid
1%
- + + + - -
Ascorbic acid 1% + - - + + +
Citric acid + + + + + +
Positive control + + + + + +
Negative control - - - - - -
There was significant difference between the 2 fruit types. The creole´s enzymes were more resistant.
To inhibit the peroxidase, the best treatments were salt-sugar-citric acid and salt-sugar-ascorbic-citric
acid; to inhibit catalase was salt-sugar-ascorbic acid.
The worst treatment to inhibit these enzymes was salt, although in color change in exposition to air, it
was the best one. In the figure 1, it is shown some of the treatments applied.
The peroxidase is more sensitive to these chemical agents, and the catalase may be not so involve in
the enzymatic reaction, because of the results presented in the table.
The peroxidase and catalase are not the only enzymes that are involved in this reaction, because in
some treatments, the exposition to air did not change the color of the hawthorn and the tests of these
enzymes were negative.