Effect of Conditioning Methods on Mechanical Properties of Raw Bael Fruit

Background: Bael is an important indigenous fruit, which is rich in nutritional and health promoting factors. Development of value-added products from this fruit poses a problem as the fruit has a hard rind and is difficult to be removed by hand. Methods: The objective of this investigation was to evaluate the effect of different conditioning methods as normal water dipping (25-27°C), chilling (10-11°C), freezing (4-5°C) and hot water dipping (90-95°C) on firmness and other mechanical properties of raw and matured bael fruit, with a goal of devising some methods for easy removal of the rind. The fruits after conditioning were subjected to puncture test by universal testing machine. Distinct peaks were observed on the force-displacement traces which indicated the rupture force and firmness of the fruits. The changes observed in rupture force, deformation and firmness in conditioned samples were compared. Result: Rupture force measured for control sample (kept under ambient conditions) was 344.4±27.13 N and was found to be lower than that of the conditioned samples. The minimum rupture force of 192.6±14.41 N was observed in frozen sample. No significant difference in rupture force could be observed between the normal water dipped sample and chilled samples. Hot water dipped sample required a rupture force of 215.3±29.2 N, which was not significantly (p greater than 0.05) less than those of other treatments but, the green color of the fruits degraded to brown. The change in other mechanical properties also remained similar. The results would be useful for preparing the raw bael fruit for further processing and value addition.

Thermal and Mechanical Stabilities of Core-shell Microparticles Containing a Liquid Core

Thorough understanding of the behaviour of core-shell microparticles with a liquid core is essential for determining their performance in applications under different operation conditions. This paper reports the behaviour of core-shell particles with a liquid core under thermal and mechanical loads. First, we formulated an analytical model for the heating process of a core-shell microparticle with a liquid core. Next, we utilised an axisymmetric model of an elastic spherical shell upon compression to describe the deformation of a core-shell microparticle. Finally, we conducted experiments to validate these models. Both thermal and mechanical models agree well with the experimental data. The maximum temperature a core-shell microparticle can withstand depends on the liquid, the geometry, and the material of the shell. The critical compression force before rupture of a core-shell microparticle depends on the Poisson’s ratio of the shell material and the shell thickness relative to the outer shell radius. The rupture force and rupture temperature increase with increasing shell thickness.

Thermal and Mechanical Stabilities of Core-shell Microparticles Containing a Liquid Core

Thorough understanding of the behaviour of core-shell microparticles with a liquid core is essential for determining their performance in applications under different operation conditions. This paper reports the behaviour of core-shell particles with a liquid core under thermal and mechanical loads. First, we formulated an analytical model for the heating process of a core-shell microparticle with a liquid core. Next, we utilised an axisymmetric model of an elastic spherical shell upon compression to describe the deformation of a core-shell microparticle. Finally, we conducted experiments to validate these models. Both thermal and mechanical models agree well with the experimental data. The maximum temperature a core-shell microparticle can withstand depends on the liquid, the geometry, and the material of the shell. The critical compression force before rupture of a core-shell microparticle depends on the Poisson’s ratio of the shell material and the shell thickness relative to the outer shell radius. The rupture force and rupture temperature increase with increasing shell thickness.

A Study on Rupture Resistance of Groundnut (cv. SAMNUT 22) Kernel

This study was done to assess the influence of compression loading rate and kernel size on the rupture resistance of groundnut (cv. SAMNUT 22) kernel. These groundnut kernel mechanical parameters (rupture force, deformation at rupture, rupture power, firmness and toughness) were evaluated under three loading rates (15 mm min-1, 20 mm min-1 and 25 mm min-1), and three size categories (small, medium and large). The groundnut kernels were harvested at peak maturity stage, and tested in accordance to ASTM International standards. Results obtained from the tests showed that the rupture resistance of SAMNUT 22 kernel was highly dependent on its size and the loading rate. Generally, as the loading rate increases, the mechanical parameters values declined significantly (p ≤ 0.05). Rupture force, deformation at rupture point, rupture power and the firmness increased as the kernel size increases; but in contrast, the kernel toughness decreases as its size increased. An average force of 57.96 N ruptured the large kernel, while a lower force of 27.35 N ruptured the small kernel. Moreover, the large kernel recorded the highest firmness (59.03 N mm-1), when compared to the medium (51.69 N mm-1) and small (44.98 N mm-1) size kernel. In terms of rupture power, the small kernel power ranged from 0.1002 W (15 mm min-1) to 0.084 W (25 mm min-1); medium size kernel ranged from 0.115 W (15 mm min-1) to 0.074 W (25 mm min- 1); while the large size kernel ranged from 0.135 W (15 mm min-1) to 0.104 W (25 mm min-1). These results portrayed importance of sorting of the groundnut kernels before processing unit operation, as it will help to conserve power and energy during the processing operation.

The activation efficiency of mechanophores can be modulated by adjacent polymer composition

Chemical modifications of the linking units between a mechanophore and the polymer backbone can significantly enhance or reduce the rupture force of the mechanophore.

Investigation of the Influence of Calcium Salts and Gelling Time on the Structural Mechanical Properties of Fruit Jam

Alginate beads attract attention as a encapsulation matrix of bioactive substances in food. However, the stability of beads depends on calcium ion and sodium alginate concentration, gelling time and others factors. The aim of this study is to investigate the influence of different types of calcium salts on the structural and mechanical parameters - the rupture force and rupture deformation at different gelling times of the pear jam prepared with soluble dietary fibers and inulin. The relationships between the rupture force and rupture deformation of the fruit jams were established. By increasing the gelling time from 24 hours to 48 hours, the rupture deformation of jams with 7% calcium lactate were reduced and in those with 7% CaCl2 the rupture forces increases. Any change in rupture force was observed for the jam with 3.5% CaCl2. This study demonstrated the practical application of different calcium salts for preparation of stable pear jam.

The Effect of Starch and Amidated Pectin on Rheological Behavior of Iota-Carrageenan Gels

Experiments were conducted to study the rheological behavior of iota-carrageenan Gels to which potato starch and low-esterified amidated pectin were added. The rheological measurements of carrageenan jellies were performed by a texture analyzer at different concentrations of gelling agent (iota-carrageenan) and fixed concentrations of starch (1.3 %) and pectin (0.3%). Following the experiments, rheological patterns related to rupture force, rupture deformation and firmness of the gels were evaluated. Potato starch and low esterified amidated pectin at certain concentrations do not show synergistic effects with iota-carrageenan. The addition of low esterified amidated pectin or potato starch in iota-carrageenan gel results in a significant reduction in deformation and a minimal reduction in the rupture force.

The Local Environment of Iron Determines the Rupture Force of Rubredoxin and Not Hydrogen Bond Networks

<div> <div> <div> <p>The surprisingly low rupture force and remarkable mechanical anisotropy of rubredoxin have been known for several years. Exploiting the first combination of steered molecular dynamics and the quantum chemical Judgement of Energy DIstribution (JEDI) analysis, the distribution of strain energy in the central part of rubredoxin is elucidated in real-time with unprecedented detail. In contrast to common belief that hydrogen bonds between neighboring amino acid backbones and the sulfur atoms of the central FeS4 unit in rubredoxin determine the low mechanical resistance of the protein, we demonstrate that structural anisotropy as well as the contribution of angle bendings in the FeS4 unit are instead the key factors responsible for the low rupture force in rubredoxin. In addition to clarifying the structural basis for the mechanical unfolding of an important metalloprotein, this study paves the way for in-depth investigations of an intriguing new class of mechanophores involving metal ions. </p> </div> </div> </div>

The Local Environment of Iron Determines the Rupture Force of Rubredoxin and Not Hydrogen Bond Networks

<div> <div> <div> <p>The surprisingly low rupture force and remarkable mechanical anisotropy of rubredoxin have been known for several years. Exploiting the first combination of steered molecular dynamics and the quantum chemical Judgement of Energy DIstribution (JEDI) analysis, the distribution of strain energy in the central part of rubredoxin is elucidated in real-time with unprecedented detail. In contrast to common belief that hydrogen bonds between neighboring amino acid backbones and the sulfur atoms of the central FeS4 unit in rubredoxin determine the low mechanical resistance of the protein, we demonstrate that structural anisotropy as well as the contribution of angle bendings in the FeS4 unit are instead the key factors responsible for the low rupture force in rubredoxin. In addition to clarifying the structural basis for the mechanical unfolding of an important metalloprotein, this study paves the way for in-depth investigations of an intriguing new class of mechanophores involving metal ions. </p> </div> </div> </div>