Browsing by Author "Goh KKT"

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    Does harvesting age matter? Changes in structure and rheology of a shear-thickening polysaccharide from Cyathea medullaris as a function of age
    (Elsevier Ltd, 2024-04-01) Bisht A; Goh KKT; Sims IM; Edwards PJB; Matia-Merino L
    A shear-thickening polysaccharide from the New Zealand Black tree fern (Cyathea medullaris, commonly known as mamaku) extracted from different age fronds (stage 1: young, stage 2: fully grown and stage 3: old) was characterised in terms of structure and rheological properties. Constituent sugar analysis and 1H and 13C NMR revealed a repeating backbone of −4)-β-D-GlcpA-(1 → 2)-α-D-Manp-(1→, for all mamaku polysaccharide (MP) samples from different age fronds without any alterations in molecular structure. However, the molecular weight (Mw) was reduced with increasing age, from ~4.1 × 106 to ~2.1 × 106 Da from stage 1 to stage 3, respectively. This decrease in Mw (and size) consequently reduced the shear viscosity (ηs-Stage 1 > ηs-Stage 2 > ηs-Stage 3). However, the extent of shear-thickening and uniaxial extensional viscosity of MP stage 2 was greater than MP stage 1, which was attributed to a greater intermolecular interaction occurring in the former. Shear-thickening behaviour was not observed in MP stage 3.
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    Effects of Incorporating Alkaline Hydrogen Peroxide Treated Sugarcane Fibre on The Physical Properties and Glycemic Potency of White Bread
    (MDPI (Basel, Switzerland), 2023-03-29) Binte Abdul Halim FN; Taheri A; Yassin ZAR; Chia KF; Goh KKT; Goh SM; Du J
    The consumption of dietary fibres can affect glycemic power and control diabetes. Sugarcane fibre (SCF) is known as insoluble dietary fibre, the properties of which can be affected by physical, chemical, and enzymatic treatments. In this study, alkaline hydrogen peroxide (AHP) treatments were conducted over time (0.5, 1, 3, and 5 h) at 12.6% (w/v) SCF and the effects on the physicochemical and structural properties of the SCF were evaluated. After making dough and bread with the SCF, with and without AHP treatments, the glycemic responses of the bread samples were evaluated. Shorter durations of AHP treatment (0.5 and 1 h) reduced lignin effectively (37.3 and 40.4%, respectively), whereas AHP treatment at 1 and 3 h duration was more effective in increasing particle sizes (50.9 and 50.1 μm, respectively). The sugar binding capacity, water holding capacity (from 2.98 to 3.86 g water/g SCF), and oil holding capacity (from 2.47 to 3.66 g oil/g SCF) increased in all AHP samples. Results from Fourier-transform infrared spectroscopy (FTIR) confirmed the polymorphism transition of cellulose (cellulose I to cellulose II). The morphology of SCF detected under scanning electron microscopy (SEM) indicated the conversion of the surface to a more porous, rough structure due to the AHP treatment. Adding SCF decreased dough extensibility but increased bread hardness and chewiness. All SCF-incorporated bread samples have reduced glycemic response. Incorporation of 1, 3, and 5 h AHP-treated SCF was effective in reducing the glycemic potency than 0.5 h AHP-treated SCF, but not significantly different from the untreated SCF. Overall, this study aims to valorize biomass as AHP is commonly applied to bagasse to produce value-added chemicals and fuels.
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    Effects of microwave, ultrasound, and high-pressure homogenization on the physicochemical properties of sugarcane fibre and its application in white bread
    (Elsevier Ltd., 2023-07-15) Abdol Rahim Yassin Z; Binte Abdul Halim FN; Taheri A; Goh KKT; Du J
    Sugarcane fibre (SCF) is known as an insoluble dietary fibre and a by-product from sugar manufacturing industry. The physicochemical and structural properties of SCF were modified using microwave irradiation at 5% and 10% SCF for 5 and 10 min (MW5%,15m, MW10%,5m, MW10%,15m), ultrasound at 30% amplitude, 7% SCF, for 1.5 h or 3 h (US1h, US2h), and high-pressure homogenization at 1% SCF, 2000 bar for 1 and 2 passes (HPH1p, HPH2p). Different types of disruption on the morphology of SCF were observed with different physical treatments confirmed by scanning electron microscopy. HPH2p treated SCF exhibited the largest particle size, and highest water and oil-holding capacities. Fourier-transform infrared spectroscopy results showed that all physical treatments were able to reduce hemicellulose and enhance cellulose content in SCFs, especially for HPH treatments. After making dough and bread with treated and untreated SCF, HPH2p SCF incorporated bread had the firmest texture, followed by MW10%,15m, while these two samples have the lowest specific volume. The maximum height of bread was significantly lower in breads incorporated with HPH2p, US1.5h and US3h. Subsequently, glycemic response decreased in all SCF-incorporated breads compared to white bread reference.
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    Process-structure-function relationship for mamaku suspension: Effect of drying methods on powder functionality
    (Elsevier Ltd., 2023-12-30) Bisht A; Goh KKT; Matia-Merino L
    The pith from mamaku tree fern entraps a unique shear-thickening biomacromolecule called mamaku polysaccharide (MP) that may alter the rheological profile in the gut. Here we examined the potential of using the whole pith—natural entrapment of MP in the tissue of pith—to develop a food ingredient with shear-thickening behaviour as an alternative to MP extract. In this study, fresh mamaku pith was collected and dried using an oven-dryer or freeze-dryer, and ground into a powder (ODP: oven-dried powder; FDP: freeze-dried powder). Both the ODP and FDP were characterised for their physical properties (colour, densities, surface morphology), rehydration in water, rheological behaviour and in vitro starch digestion. Freeze-drying resulted in a porous structure, while after oven-drying, the structure collapsed and an increase in density was observed. Upon rehydration with water, both FDP and ODP absorbed water, causing the powder particles to swell and release the water-soluble compounds into the continuous phase. The ability of FDP to release water-soluble MP into the continuous phase resulted in a rheological behaviour of a suspension similar to MP extract solution (shear-thickening behaviour). No shear-thickening was observed in ODP suspension because not enough MP was available in the continuous phase to form polymer-polymer interactions. In-vitro digestion of wheat biscuits mixed with rehydrated FDP suspension reduced starch digestion by ∼35% after 10 min, but starch digestion was unaffected by ODP suspension. This was due to the changes in the rheological behaviour resulting from the alteration in structural characteristics of the powder samples by the different drying methods.