Browsing by Author "Bronlund JE"

Now showing 1 - 6 of 6
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    Chewing behavior and bolus properties as affected by different rice types
    (World Academy of Science, Engineering and Technology, 2012) Moongngarm A; Bronlund JE; Grigg N; Sriwai N; Wong, ATC; Chin, KS; XU, MM
    The study aimed to investigate the effect of rice types on chewing behaviours (chewing time, number of chews, and portion size) and bolus properties (bolus moisture content, solid loss, and particle size distribution (PSD)) in human subjects. Five cooked rice types including brown rice (BR), white rice (WR), parboiled white rice (PR), high amylose white rice (HR) and waxy white rice (WXR) were chewed by six subjects. The chewing behaviours were recorded and the food boluses were collected during mastication. Rice types were found to significantly influence all chewing parameters evaluated. The WXR and BR showed the most pronounced differences compared with other rice types. The initial moisture content of un-chewed WXR was lowest (43.39%) whereas those of other rice types were ranged from 66.86 to 70.33%. The bolus obtained from chewing the WXR contained lowest moisture content (56.43%) whilst its solid loss (22.03%) was not significant different from those of all rice types. In PSD evaluation using Mastersizer S, the diameter of particles measured was ranged between 4 to 3500μm. The particle size of food bolus from BR, HR, and WXR contained much finer particles than those of WR and PR.
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    Contribution of the proximal and distal gastric phases to the breakdown of cooked starch-rich solid foods during static in vitro gastric digestion.
    (Elsevier, 2022-07) Nadia J; Bronlund JE; Singh H; Singh RP; Bornhorst GM
    In vitro gastric digestion studies commonly focus on the acidic environment of the stomach (the distal phase), neglecting that the contact time between food and salivary amylase can be extended during bolus' temporary storage in the proximal stomach (the proximal phase). Consequently, the role of the proximal phase of gastric digestion on the breakdown of solid starch-based foods is not well understood. This study aimed to address this question using a static in vitro digestion approach. Cooked starch-rich foods of different physical structures (wheat couscous, wheat pasta, rice couscous, rice noodle, and rice grain) were subjected to 30 s oral phase digestion, followed by prolonged incubation of the oral phase mixture (pH 7) for up to 30 min representing different proximal phase digestion times. Each proximal phase sample was sequentially incubated in excess simulated gastric fluid (distal phase, pH 2) for up to an additional 180 min. The proximal phase aided solid food breakdown through starch hydrolysis that caused leaching of particles <2 mm. The distal phase led to softening of food particles, but the softening process was not enhanced with longer proximal phase. In foods with smaller initial size (couscous and rice couscous), a proximal phase of 15 min or longer followed by 180-min distal phase increased starch hydrolysis in the liquid and suspended solid fractions of the digesta, indicating the influence of food structure on acid hydrolysis during in vitro gastric digestion.
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    Influence of different box preparations on creep performance of corrugated fibreboard boxes subject to constant and cycling relative humidity environments
    (John Wiley and Sons, Ltd, 2022-06-01) Gray-Stuart EM; Wade K; Redding GP; Parker K; Bronlund JE
    To understand the effect of load and relative humidity (RH) on box creep in cool storage conditions, standard tests are performed. However, these test conditions are oversimplified compared with actual shipping conditions. Our aim is to develop test conditions that more closely mimic those encountered during refrigerated conditions to investigate their influence on creep performance and box lifetime. We compared three box preparations: (i) empty boxes used as a control, (ii) filled boxes, and (iii) boxes with only two side panels exposed to the atmosphere. A controlled environment test facility was used to subject sets of 24 boxes to 30% of their ultimate failure load under different cyclic and constant relative humidity conditions. Results indicate that filled boxes had substantially reduced performance in terms of secondary creep rate and lifetime. The fill in the box contributed to out-of-plane displacement of the side panels which manifested earlier than in the control, resulting in a higher creep rate. Boxes with only two exposed panels had lower moisture uptake and performed substantially better than the control. These findings demonstrate how creep performance and box lifetime depend on the box conditions including fill and the area of the box that is exposed for moisture transfer. Alternative box preparations which mimic supply chain conditions are worthy of investigation in creep analysis as they will help predict more accurately box performance in the cold supply chain.
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    Modelling the role of oral processing on in vivo aroma release of white rice: Conceptual model and experimental validation
    (Elsevier Ltd, 2021-04) How MS; Jones JR; Morgenstern MP; Gray-Stuart E; Bronlund JE; Saint-Eve A; Trelea IC; Souchon I
    A conceptual model was developed to relate oral processing parameters and aroma release of cooked white rice. The conceptual model indicates that aroma release is dependent on the increase of particle surface area, the dilution effect of saliva and the diffusion of aroma from food residues that can be trapped in the buccal-pouches in the mouth. The model was validated against in vivo retro-nasal aroma release data during the consumption of rice flavoured with two aroma compounds (2-nonanone and ethyl propanoate) by five panellists. The oral processing behaviour of each subject was characterised at four different stages during oral processing by measuring bolus particle size, saliva content and the amount of residue particles that could be washed from the mouth after bolus expectoration. The results showed that aroma release for all subjects were dependent on the particle breakdown pathways used in oral processing. Subjects who reduced the rice to smaller particle sizes, higher pasted fraction and higher bolus residues had higher aroma release as expected from the conceptual model. Accounting for the physiological variables of subjects, the physicochemical parameters of aroma compounds and using a larger number of subjects in future studies will improve the model reliability.
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