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Pontamine fast scarlet 4B bifluorescence and measurements of cellulose microfibril angles

Thomas J, Idris NA, Collings DA

J Microsc, 2017 10;268(1):13-27.
PMID: 28654160 DOI: 10.1111/jmi.12582

Pontamine fast scarlet 4B is a red paper and textiles dye that has recently been introduced as a fluorescent probe for plant cell walls. Pontamine exhibits bifluorescence, or fluorescence dependent on the polarization of the excitation light: Because cellulose is aligned within the cell wall, pontamine-labelled cell walls exhibit variable fluorescence as the excitation polarization is modulated. Thus, bifluorescence measurements require polarized excitation that can be directly or indirectly modulated. In our confocal microscopy observations of various cellulose samples labelled with pontamine, we modulated excitation polarization either through sample rotation or by the confocal's scanfield rotation function. This variably rotated laser polarizations on Leica confocal microscopes, but not those from other makers. Beginning with samples with directly observable microfibril orientations, such as purified bacterial cellulose, the velamen of orchid roots and the inner S2 layer of radiata pine compression wood, we demonstrate that modelling the variations in pontamine fluorescence with a sine curve can be used to measure the known microfibril angles. We then measured average local microfibril angles in radiata pine samples, and showed similar microfibril angles in compression and normal (opposite) wood. Significantly, bifluorescence measurements might also be used to understand the degree of local cellulose alignment within the cell wall, as opposed to variations in the overall cellulose angle.
Fulltext Inter-esterified palm products as alternatives to hydrogenation

Idris NA, Dian NL

Asia Pac J Clin Nutr, 2005;14(4):396-401.
PMID: 16326647

Inter-esterification is one of the processes used to modify the physico-chemical characteristics of oils and fats. Inter-esterification is an acyl-rearrangement reaction on the glycerol molecule. On the other hand, hydrogenation involves addition of hydrogen to the double bonds of unsaturated fatty acids. Due to health implications of trans fatty acids, which are formed during hydrogenation, the industry needs to find alternatives to hydrogenated fats. This paper discusses some applications of inter-esterified fats, with particular reference to inter-esterified palm products, as alternatives to hydrogenation. Some physico-chemical properties of inter-esterified fats used in shortenings are discussed. With inter-esterification, more palm stearin can be incorporated in vanaspati. For confectionary fats and infant formulations, enzymatic inter-esterification has been employed.
Antioxidative properties of Pandanus amaryllifolius leaf extracts in accelerated oxidation and deep frying studies

Nor FM, Mohamed S, Idris NA, Ismail R

Food Chem, 2008 Sep 15;110(2):319-27.
PMID: 26049222 DOI: 10.1016/j.foodchem.2008.02.004

The potential uses of Pandanus amaryllifolius leaf extract as a natural antioxidant were evaluated in refined, bleached and deodorized (RBD) palm olein, using accelerated oxidation and deep frying studies at 180°C from 0 to 40h. The extracts (optimum concentration 0.2%) significantly retarded oil oxidation and deterioration (P<0.05), comparably to 0.02% BHT in tests such as peroxide value, anisidine value, iodine value, free fatty acid, oxidative stability index (OSI), polar and polymer compound contents. In sensory evaluation studies, different batches of French fries were not significantly different (P<0.05) from one another for oiliness, crispiness, taste and overall acceptability when the same oil was used for up to the 40th hour of frying. P. amaryllifolius leaf extract, which had a polyphenol content of 102mg/g, exhibited an excellent heat-stable antioxidant property and may be a good natural alternative to existing synthetic antioxidants in the food industry.
Fulltext The Orchid Velamen: A Model System for Studying Patterned Secondary Cell Wall Development?

Idris NA, Aleamotuʻa M, McCurdy DW, Collings DA

Plants (Basel), 2021 Jul 02;10(7).
PMID: 34371560 DOI: 10.3390/plants10071358

Understanding the mechanisms through which plants generate secondary cell walls is of more than academic interest: the physical properties of plant-derived materials, including timber and textiles, all depend upon secondary wall cellulose organization. Processes controlling cellulose in the secondary cell wall and their reliance on microtubules have been documented in recent decades, but this understanding is complicated, as secondary walls normally form in the plant's interior where live cell imaging is more difficult. We investigated secondary wall formation in the orchid velamen, a multicellular epidermal layer found around orchid roots that consists of dead cells with lignified secondary cell walls. The patterns of cell wall ridges that form within the velamen vary between different orchid species, but immunolabelling demonstrated that wall deposition is controlled by microtubules. As these patterning events occur at the outer surface of the root, and as orchids are adaptable for tissue culture and genetic manipulation, we conclude that the orchid root velamen may indeed be a suitable model system for studying the organization of the plant cell wall. Notably, roots of the commonly grown orchid Laelia anceps appear ideally suited for developing this research.
Changes of headspace volatile constituents of palm olein and selected oils after frying French fries

Omar MN, Nor NN, Idris NA

Pak J Biol Sci, 2007 Apr 01;10(7):1044-9.
PMID: 19070048

Changes of aroma constituents of palm olein and selected oils after frying French fries have been studied. The aroma constituents of used oils were collected using a solid-phase microextraction (SPME) headspace technique with an absorbent of a divinylbenzene/carboxen (DVB/CAR) (50/30 microm) on polydimethylsiloxane (PDMS) fibre. The extracted volatiles were desorbed from the fibre in the injection port of the gas chromatograph at 250 degrees C and the aroma constituents were identified by GC-MS. Analytical data showed that volatile constituents of palm olein, soybean oil, corn oil and sunflower oil changed while frying continued from 2 to 40 h, respectively. In palm olein, the 2t,4t-decadienal content decreased from 14.7 to 5.5 microg g(-1) (40 h) whilst hexanal increased from 7.9 microg g(-1) (2 h) to 29.2 microg g(-1) (40 h), respectively. Similar result was also obtained from soybean oil after frying French fries. The 2t,4t-decadienal content decreased from 15.9 microg g(-1) (2 h) to 3.2 microg g(-1) after 40 h frying whilst hexanal increased from 10.2 microg g(-1) (2 h) to 34.2 microg g(-1) (40 h). Meanwhile, in corn oil, it was found that 2t,4t-decadienal decreased from 15.6 microg g(-1) (2 h) to 3.2 microg g(-1) (40 h) whilst hexanal increased from 11.3 microg g(-1) (2 h) to 33.8 microg g(-1) when frying time reached 40 h. In sunflower oil, it was found that 2t,4t-decadienal, decreased from 16.8 microg g(-1) (2 h) to 1.2 microg g(-1) (40 h) while hexanal increased from 9.5 microg g(-1) (2 h) to 32.4 microg g(-1) when frying time reached 40 h. It also showed that used oils exhibited off-odour characteristics due to the increasing amount ofhexanal while their freshness characteristics diminished due to the decreasing amount of 2t, 4t-decadienal.
Physico-chemical properties and performance of high oleic and palm-based shortenings

Ramli MR, Lin SW, Yoo CK, Idris NA, Sahri MM

J Oleo Sci, 2008;57(11):605-12.
PMID: 18838833

Solid fat from fractionation of palm-based products was converted into cake shortening at different processing conditions. High oleic palm stearin with an oleic content of 48.2 % was obtained from fractionation of high oleic palm oil which was produced locally. Palm product was blended with different soft oils at pre-determined ratio and further fractionated to obtain the solid fractions. These fractions were then converted into cake shortenings named as high oleic, N1 and N2 blends. The physico-chemical properties of the experimental shortenings were compared with those of control shortenings in terms of fatty acid composition (FAC), iodine value (IV), slip melting point (SMP), solid fat content (SFC) and polymorphic forms. Unlike the imported commercial shortenings as reported by other studies and the control, experimental shortenings were trans-free. The SMP and SFC of experimental samples, except for the N2 sample, fell within the ranges of commercial and control shortenings. The IV was higher than those of domestic shortenings but lower when compared to imported and control shortenings. They were also observed to be beta tending even though a mixture of beta and beta' was observed in the samples after 3 months of storage. The shortenings were also used in the making of pound cake and sensory evaluation showed the good performance of high oleic sample as compared to the other shortenings.
The Effectiveness of Tuberculosis Education Programme in Kelantan, Malaysia on Knowledge, Attitude, Practice and Stigma Towards Tuberculosis among Adolescents

Idris NA, Zakaria R, Muhamad R, Nik Husain NR, Ishak A, Wan Mohammad WMZ

Malays J Med Sci, 2020 Dec;27(6):102-114.
PMID: 33447138 DOI: 10.21315/mjms2020.27.6.10

Background: Tuberculosis (TB) is contagious and the transmission risk is high in congregate settings like school. Incidence of TB among adolescents is significantly high hence an education programme was developed to improve knowledge, attitude, practice and stigma (KAPS) among them.
Methods: This school-based, non-randomised controlled study was conducted among secondary school students with a total of 236 respondents. The KAPS score were assessed before and 1 month after using self-administered validated KAPS questionnaire on TB. Analysis was done using repeated measures ANOVA.
Results: The mean percentage score (SD) for baseline knowledge, attitude, practice and stigma score for the respondents were 54.0 (4.48), 65.6 (1.74), 70.0 (1.43) and 66.0 (6.88), respectively. There was a significant difference (P < 0.001) in the knowledge and stigma score for intervention group compared to control group, adjusted for gender, ethnicity and smoking status 4 weeks post-TB educational programme. However, with regards to attitude and practice score, there was no significant difference (P = 0.210 and P = 0.243, respectively).
Conclusion: TB education programme was effective in improving knowledge and stigma related to TB. This health education programme can be used as one of the strategies for the prevention and control of TB in schools.