Citation
Wong, Mei Chee
(2004)
Physico-Chemical and Biochemical Changes of Capsicum Annuum Var. Kulai During Development and Using Modified Atmosphere Packaging System.
Masters thesis, Universiti Putra Malaysia.
Abstract
The objective of this study is to determine the optimal hawesting stage for
Capsicum annuum var. kulai. Capsicum annuum var. kulai was harvested
weekly from day 21 to day 49 after anthesis and analysed for its physico
chemical and biochemical changes during growth, maturation and ripening.
Analysis were carried out at five stages: immature green (d 21), mature
green (d 28), breaker (d 35), red (d 42) and ripen red (d 49). Physicochemical
and biochemical parameters were analysed. They included
determining of the fruit colour, weight loss, firmness, ethylene and carbon
dioxide (C02) production, pigment contents, carotenoid contents, organic
acids contents, sugars, starch, pectin, capsaisinoids contents, and cell wall
degradative enzymes activities. This study also aims to determine the
effects of Modified Atmosphere Packaging (MAP) in prolonging its shelf life.
Experiments were carried out using packaging materials such as Pow Vinyl
Chloride (PVC) cling wrap, Low Density Polyethylene (LDPE), High Density Polyethylene (HDPE) and Propylene (PP) to determine the effects of
diirent packaging materials on shelf life of Capsicum annuum var. kulai.
The effects of combined LDPE and MAP on shelf life of Capsicum annuum
var. kulai were also evaluated. Results showed capsicum annuum var. kulai
was fully developed between day 35 and day 42 after anthesis, but no
significant changes in fresh weight from day 35 to day 42 after anthesis were
recorded. Whist the dour of the fruits turned from breaker (day 35) to red
(day 42). Pungency components such as capsaicin and dihydrocapsaicin
reached maximum on day 42 after anthesis and began to decrease
thereafter. Therefore, in order to maintain pungency components, the fruits
should be harvested before day 42 of anthesis. Specific activity of
degradative enzymes such as polygalacturonase (PG), pectin
methylesterase (PME), a-D-mannosidase, p-D-galacturonase, cellulase and
xylanase were identified at various stages of growing, maturation and
ripening. PG activity which reached maximum at day 42 after anthesis was
found to be relatively higher than PME and cellulase activity in capsicum
annuum. Cellulase, xylanase, p-D-galacturonase and a-D-mannosidase
activities did not show any effect in promoting softening of the fruit.
Production of ethylene and COZ which are important during ripening of
Capsicum annuum, increased fmm 4.54 to 12.24 pUhr/kg and 1.72 to 3.14
pUhr/kg respectively. Physical appearance of LDPE packaged Capsicum
annuum did not change significantly until after 30 days of fruits storage. This
was indicated by delay in shriveling, insignificant loss of fresh weight,
firmness, absence of pedicel and calyx discdouration and decay. Study on
firmness and freshness of capsicum showed no significant changes when stored under combined sealed LDPE bag for 30 days compared to
perforated LDPE bag. It was also found that sealed LDPE bag was able to
prolong fruit freshness which moisture loss was recorded less than 0.45%
during the 30 days storage. Capsaicin and dihydrocapsaicin, which are
important for pungency of the fruits, did not show any significant changes
during the storage. In addition, physical appearance and natural nutrients of
capsicum were maintained when packed in sealed LDPE bags. Results also
indicated that sealed LDPE bag was found to be the best for extension of the
storage life of Capsicum annuum var. kulai up to 30 days after harvesting at
day 42 from anthesis.
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