DOSES OF GAMMA IRRADIATION AFFECTING POSTHARVEST QUALITY OF
FINGERROOT DURING STORAGE

MISS HUYNH MINH NGUYET

A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR
THE DEGREE OF BACHELOR OF SCIENCE (FOOD TECHNOLOGY)
SCHOOL OF BIORESOURCES AND TCHNOLOGY
KING MONGKUT’S UNIVERSITY OF TECHNOLOGY THONBURI
HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION
2019

I

ABSTRACT
Gamma irradiation has become one of the effective food technology to reduce risk of food
poisoning and preserve quality. The effect of doses of gamma irradiation on postharvest quality
has been repoted in various fruits and vegetables. This study was aimed to investigate the
changes in postharvest quality of fingerroot rhizome and fresh – cut fingerroot after irradiation
by different doses of gamma ray. In experiment on fingerroot rhizome, all samples were treated
with gamma ray at 0 (control), 1.0, 2.0 and 4.0 kGy and then stored at 13°C for 12 days of
storage. The results showed that there were no significant differences in physical properties of
fingerroot which were weight loss and colour peel change value during storage. Moreover,
gamma irradiation did not affect on total phenolic content, total flavonoid content and DPPH
radical scavenging activity of fingerroot rhizome as compared to the control. However, samples
at doses of 2.0 and 4.0 kGy resulted in the reduction of vitamin C content stored at 13°C. Thus,
gamma irradiation with dose of 1.0 kGy obtained better conditions in controlling postharvest
quality of fingerroot rhizome than other treatments. On the other hand, all samples of fresh – cut
fingerroot were irradiated by gamma ray with doses of 0 (control), 0.5 and 2.0 kGy and stored at
4°C during 8 days. The data revealed that irradiation did not obviously change in colour value of
fresh – cut fingerroot at storage period, in comparison with the unirradiated sample. Neither
radiation treatment nor storage condition had siginificant effect on browning value, sensory
evaluation and internal gases inside package of fresh – cut fingerroot. All treatmetns increased
total phenolic content, but vitamin C content decreased gradually during storage and reached its
lowest values at the end of the storage period. In addition, fresh – cut fingerroot treated with 0.5
and 2.0 kGy showed a significant reduction microorganism more than the non – irradiated
sample at every stages of period. Therefore, gamma irradiation at 0.5 kGy effectively maintained
pos
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