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Papers by Natta Laohakunjit

Effect of gamma radiation at 0, 300, 600 and 900 Gy on sensory evaluation of dragon fruits was ob... more Effect of gamma radiation at 0, 300, 600 and 900 Gy on sensory evaluation of dragon fruits was observed by using 12 semi trained panelists. The potential of the gamma irradiation for the oriental fruit fly quarantine treatment could be affected on quality of sweet aroma, fruit firmness, sweetness, sourness, and overall acceptance. After treated with gamma ray for 5

LWT - Food Science and Technology, 2016

Journal of Food Science and Technology, 2016

วารสารวิจัยและพัฒนา มจธ, 2011

Bioscience, Biotechnology, and Biochemistry, 2015

Sulfated polysaccharides (SPs) from Gracilaria fisheri of Thailand, which were extracted in low-t... more Sulfated polysaccharides (SPs) from Gracilaria fisheri of Thailand, which were extracted in low-temperature (25 °C) water showed the highest content of phenolic compounds compared with those extracted at high temperature (55 °C). Crude SP antioxidant activity was evaluated by measuring the DPPH free radical scavenging effect which is directly related to the level of phenolic compounds. The sulfate content, total sugar, and SPs yield were also directly related to the extraction temperature. All extracts contained galactose as a major monosaccharide. High antioxidant activity of crude SP, positively correlated with the phenolic compound contents (R(2) = 0.996) contributed by the existence of sulfate groups and phenolic compounds. In purified SP, F1 fraction exhibited strong radical scavenging ability, but it was not significantly different compared to crude SP extracted at 25 °C. This indicated that the appropriate density and distribution of sulfate groups in the SP extract showed the best antioxidant activity.

International Journal of Biological Macromolecules, 2015

Ulva intestinalis, a tubular green seaweed, is a rich source of nutrient, especially sulphated po... more Ulva intestinalis, a tubular green seaweed, is a rich source of nutrient, especially sulphated polysaccharides. Sulphated polysaccharides from U. intestinalis were extracted with distilled water, 0.1N HCl, and 0.1N NaOH at 80°C for 1, 3, 6, 12, and 24h to study the effect of the extraction solvent and time on their chemical composition and antioxidant activity. Different types of solvents and extraction time had a significant influence on the chemical characteristics and antioxidant activity (p&lt;0.05). Monosaccharide composition and FT-IR spectra analyses revealed that sulphated polysaccharides from all solvent extractions have a typical sugar backbone (glucose, rhamnose, and sulphate attached at C-2 or C-3 of rhamnose). Sulphated polysaccharides extracted with acid exhibited greater antioxidant activity than did those extracted with distilled water and alkali. The results indicated that solvent extraction could be an efficacious method for enhancing antioxidant activity by distinct molecular weight and chemical characteristic of sulphated polysaccharides.

The effects of irradiation on volatile compounds of mango fruits were investigated. Mango (Mangif... more The effects of irradiation on volatile compounds of mango fruits were investigated. Mango (Mangifera indica L.) fruits treated with chitosan or non-treated chitosan were gamma radiated at doses of 0 or 0.3 KGy and then stored at 13°C. Volatile compounds were identified by headspace gas chromatography and mass spectra after storage 1, 10, 20, and 30 days. Major volatile compounds included the terpenes; δ-thujene, α-pinene, δ-3-carene, mycrene, α-terpinolene and α-phellandrene. The predominant terpene was α-terpinolene. Production of terpenes after 10 days of storage was significantly lower in irradiated mangoes treated with chitosan or not treated with chitosan compared to non-irradiated fruit. There was a transient increase in terpenes in fruit treated with benomyl.

Essential oils from 5 species: holy basil, turmeric, hairy basil, kaffir lime and sweet basil wer... more Essential oils from 5 species: holy basil, turmeric, hairy basil, kaffir lime and sweet basil were extracted by simultaneous steam distillation-extraction. Refractive index values were 1.52, 1.51, 1.48, 1.51 and 1.47, respectively. Kaffir lime gave the highest yield at 0.45 %(w/w) followed by turmeric, holy basil, sweet basil and hairy basil at 0.36, 0.09, 0.05 and 0.04, respectively. For toxicity towards the maize weevil (Sitophilus zeamais), results showed that turmeric, sweet basil, holy basil and hairy basil essential oils, at concentration greater than 15 μl.cm-2, were highly toxic produced 100% mortality within 1 day after treated fumigation. However, turmeric essential oil at 7.5 μl.cm-2, lowest concentration used in this study, gave 100% mortality within 5 day after treated as fumigant. Repellent efficacy of essential oils to maize weevil showed that essential oil from hairy basil at 1-8 μl.cm-2 was the most potent repellence of 80.1-100% followed dy sweet basil, turmeric, h...

HortScience: a publication of the American Society for Horticultural Science

Journal of Composites and Biodegradable Polymers, 2014

Bioscience, biotechnology, and biochemistry, 2012

The aim of this study was to purify an acidic α-glucan-protein complex from the fruiting bodies o... more The aim of this study was to purify an acidic α-glucan-protein complex from the fruiting bodies of Pleurotus sajor-caju by using the cell wall-degrading enzymes, xylanase and cellulase. The acidic glucan-protein complex was separated from a polysaccharide extract by using DEAE Toyopearl 650M anion-exchange and Sepharose CL-6B chromatography. Its homogeneity was ensured by high-performance size-exclusion chromatography and agarose gel electrophoresis. The acidic glucan-protein complex had a molecular weight of approximately 182 kDa. Fourier transform infrared spectroscopy of the acidic glucan-protein complex revealed an α-glycosidic bond and the typical characteristics of polysaccharides and proteins. The amino acid composition of the protein moiety was dominated by proline, glycine, glutamic acid and aspartic acid, indicating that the protein was highly flexible and had a negative charge. Atomic force microscopy proved that the acidic α-glucan-protein complex existed in a spherical ...

Food and Bioprocess Technology, 2015

ABSTRACT The effect of storage temperatures on the volatile profile and physico-chemical qualitie... more ABSTRACT The effect of storage temperatures on the volatile profile and physico-chemical qualities of minimally processed durian (MPD) was investigated. The numbers of identified volatile compounds were 26 and 36 in MPD stored at 10 °C for 11 days and 30 °C for 3 days, respectively. Major sulphur-containing compounds ethanethiol, diethyl disulphide, diethyl trisulphide, and 3,5-dimethyl-1,2,4-trithiolane (isomer 1 and isomer 2) accounted for approximately 70 % of the total volatiles. These five major sulphur compounds were prominently changed during storage which related to physico-chemical qualities of MPD, especially firmness and weight loss. During storage, colour did not change, but firmness of MPD decreased from 2.95 to 2.40 kg force. Weight loss of stored MPD increased by 3-7 % and total soluble solids, sucrose, glucose, and fructose increased 1.7-, 0.5-, 1.3-, and 0.9-folds of initial values, respectively. Principal component analysis explained that 79.88 % (10 °C) and 80.48 % (30 °C) of the total variance confirmed the correlation between volatile fingerprint and physico-chemical properties of MPD, which the five sulphur-containing volatiles could be contributed as a novel chemical ripeness marker for stored MPD.