EFFECT OF HARVEST MATURITY AND DRYING METHODS ON THE QUALITY OF DEHYDRATED BITTER GOURD (Momordica charantia L.) RINGS
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Date
2008
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Abstract
A study entitled “Effect of harvest maturity and drying methods on the
quality of dehydrated bitter gourd (Momordica charantia L.) rings” was conducted
at the Division of Post Harvest Technology, IARI, New Delhi during 2006-2008. Four
bitter gourd cultivars namely Pusa Do-Mousami, Pusa Vishesh, Pusa Hybrid-1 and Pusa
Hybrid-2 were studied to find out the optimum harvest maturity of their fruits for
preparation of better quality of dehydrated bitter gourd rings.
The 12 day after fruit set of bitter gourd was found optimum harvest maturity for
preparation of dehydrated rings with maximum retention of total chlorophyll and
ascorbic acid as well as better drying and rehydration ratio prepared from all the four
cultivars. The thickness of 1.5 cm of fresh fruit slice was found to be the best for
maximum retention of nutritional quality and better sensory score in respect of colour,
flavour, texture and overall acceptability in comparison to 1.0 cm and 2.0 cm thick fruit
slices.
To optimize the pretreatments in all the four cultivars for retaining high content
of total chlorophyll, ascorbic acid, β-carotene, total carotenoids and better drying
characteristics as well as sensory qualities, the bitter gourd rings were treated with
different blanching treatments, viz. control (T0), water blanching (T1), blanching in 2 per
cent salt solution (T2), water blanching followed by soaking in 0.2 per cent KMS
solution for 15 min (T3), and soaking in 0.3 per cent KMS solution for 15 min followed
by blanching in water (T4), then dried at 58 ±20 C in a cabinet drier, up to a final
moisture content of 4-5 per cent. Among the treatments water blanching followed by
soaking in 0.2 per cent KMS solution for 15 min (T3) in PH-2 cultivar was found to be
the best for retaining high quantity of ascorbic acid, total chlorophyll, β-carotene, total
carotenoids and low contents of reducing and total sugars in the dehydrated bitter gourd
rings. However, among the cultivars, Pusa Hybrid-2 was found the best for preparation
of dehydrated bitter gourd rings.
Further to find out the most appropriate drying conditions, the treated samples
were subjected to three different drying methods, i.e., cabinet drier, solar drier and low
temperature drier. Among them, cabinet drier was found to be best drying method for
dehydration of bitter gourd rings, as it took less time to dry the material to a low
moisture content at which the product retained higher content of ascorbic acid, total
chlorophyll, β-carotene and total carotenoids with longer shelf life.
With regards to packaging material and mode of pack used for packaging and
storage study of dehydrated bitter gourd rings, the packaging material of 260 g ALPE
pouches with nitrogen gas followed by storage at low temperature was found to be the
best storage condition for retaining better nutritional qualities in comparison to other
packaging materials of 200g HDPE and 200g LDPE pouches. However, the ascorbic
acid, total chlorophyll, β-carotene, total carotenoids, rehydration ratio and sensory score
decreased with advancement of storage period, while moisture content, reducing sugars,
total sugars and NEB increased during the six months of storage.
Description
t-8062