Friday, January 27, 2012

Malaysian Dragon Fruit Growing Going Strong

Despite disease outbreak in Malaysia; some dragon fruit farms managed to escape from the catastrophe.This is due to the patience and unrentless effort to combat the disease problems.Farmers had managed to move forward from their past experiences to uphold this lucrative industry.While researchers at their utmost doing research to support the industry be it in farm production or by products. Research must be geared up in order to find new innovations and technological advancements as to cater future problems like climate change and organic farming.
A technical visit was made to a 10-acre in Selangor, to observe what are the problems faced by the growers.There are few problems that I encountered;

1. Weed control is still a challenge and this is due to high cost in weedicides like BASTA. Manual circle weeding is very tedious and laborious.
2. High cost of fertilizers. Agricultural inputs like fertilizers, pesticides, fungicides and  other chemicals have risen very high to almost 50% increase.
3. Farm management especially mechanization. Large farms should consider machinery as to ease in spraying and in-field transportation.Appropriate planting distant had to be considered and proper planning in field design should be from experts.Such as water source, sunrise and sunset (angle of the sun), etc.
4. Harvesting and grading. There should be grades for fruits like A (450-500 g), B(350-450 g),C (less than 300g), D (small).
Mr. Kelvin from Singapore and  Dr.Zainudin during field visit 

Dragon fruit farm on hillside 

Intra rows - too close for machinery to go in 

Dragon planting intercrop with soursop and chempedak. Note weed problems.

Organic fertilizer used.

Close planting of dragon fruits.

Monday, January 16, 2012

PECTINS FROM DRAGON FRUIT (Hylocereus polyrhizus) PEEL

PECTINS FROM DRAGON FRUIT (Hylocereus polyrhizus) PEEL

NAZARUDDIN, R.1*, NORAZELINA, S.M.I.1, NORZIAH, M.H.2 and ZAINUDIN, M.3
1School of Chemical Sciences and Food Technology, Faculty of Science and Technology,
Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
2School of Industry Technology, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia
3Malaysian Agriculture Research and Development Institute, 43400 Serdang, Selangor, Malaysia
*Email: naza@ukm.my

ABSTRACT

The extraction of pectin from a by-product of dragon fruit processing, was identified as an alternative source for commercial
pectin. In this work, dried alcohol-insoluble residues (AIR) of dragon fruit peels were treated separately with ammonium
oxalate/oxalic acid 0.25 %, pH 4.6, 85oC; HCl 0.03 M, pH 1.5, 85oC; and deionised water, 75oC. The pectin obtained
from these methods were compared in term of yield, color, gelling characteristic and chemical structure. The highest yield
for the extracted pectin from dragon fruit peels was 20.1 % (dry weight basis) by ammonium oxalate/oxalic acid extraction,
contained 11.2 % moisture and 6.9 % ash. Extraction by deionised water yielded 15.4 % pectin, 11.3 % moisture and 11.6
% ash. Whereas, the acid extraction gave the lowest yield 15 %), 11.1 % moisture and 12 % ash. The amount of pectin
from all extraction conditions were comparable to pectin obtained from commercial apple (12 %) or citrus (25 %). Gel
hardness test was performed for gelling properties measurement. The Fourier Transform Infrared Spectroscopy (FTIR)
was useful in the identifying dragon fruit pectins. Different conditions used in the extraction do not show a difference in
the pectin structure. With a good recovery yield and gelling properties, ammonium oxalate-extracted dragon fruit pectin
present good characteristics to be exploited industrially as food additive.
ABSTRAK
Pengekstrakan pektin daripada sisa pemprosesan buah naga telah dikenal pasti sebagai sumber alternatif bagi pektin
komersial. Dalam kajian ini, pepejal tak larut alkohol (AIR) kering daripada kulit buah naga diperlakukan secara berasingan
dengan ammonium oksalat/asid oksalik 0.25 %, pH 4.6, 85oC; HCl 0.03 M, pH 1.5, 85oC; dan air ternyahion, 75oC. Pektin
yang diperolehi melalui kaedah ini dibandingkan dari segi hasil, warna, ciri penggelan dan struktur kimia. Hasil pektin
tertinggi daripada kulit buah naga ialah 20.1 % (berat kering) menggunakan ekstraksi ammonium oksalat/asid oksalik,
mengandungi 11.2 % air dan 6.9 % abu. Ekstraksi menggunakan air ternyahion menghasilkan 15.4 % pektin, 11.3 % air
dan 11.6 % abu. Manakala, ekstraksi asid memberikan hasil yang terendah (15 %), 11.1 % air dan 12 % abu. Pektin yang
terhasil daripada semua keadaan pengekstrakan adalah setanding dengan pektin epal (12 %) atau sitrus (25 %) komersial.
Ujian kekerasan gel dilakukan bagi mengukur sifat penggelan. Spektroskopi inframerah (FTIR) amat berguna bagi mengenal
pasti pektin buah naga. Keadaan berbeza yang digunakan dalam pengekstrakan tidak menunjukkan perbezaan dalam struktur
pektin. Dengan perolehan hasil serta ciri penggelan yang baik, pektin buah naga hasil pengekstrakan menggunakan
ammonium oksalat/asid oksalik mempunyai ciri yang baik untuk diterokai secara industri sebagai bahan tambah makanan.
Key words: Dragon fruit; Pectin; Alcohol insoluble residue; Extraction conditions

Source: Malays. Appl. Biol. (2011) 40(1): 1P9E-C23TINS