Related Experiment Video
Updated: Jul 3, 2026
11:37
RGB and Spectral Root Imaging for Plant Phenotyping and Physiological Research: Experimental Setup and Imaging Protocols
Published on: August 8, 2017
Water uptake mechanism in crispy bread crust.
Neleke H van Nieuwenhuijzen1, Marcel B J Meinders, R Hans Tromp
1TI Food and Nutrition (formerly WCFS), Nieuwe Kanaal 9a, 6709 PA Wageningen, The Netherlands.
Journal of Agricultural and Food Chemistry
|July 10, 2008
Summary
This study introduces a method to measure water sorption kinetics in bread crust, crucial for maintaining crispness in dry foods. Water uptake rates vary with relative humidity and experimental timescale, revealing complex relaxation processes.
Area of Science:
- Food Science and Technology
- Materials Science
- Physical Chemistry
Background:
- Crispness is a key quality attribute in dry solid foods like crispy rolls.
- Maintaining crispness depends on the kinetics of water uptake by the food crust.
- Understanding water sorption is vital for predicting and controlling food product quality.
Purpose of the Study:
- To propose and evaluate a method for assessing water sorption kinetics in bread crust.
- To investigate the influence of different experimental timescales on water uptake dynamics.
- To elucidate the mechanisms governing water uptake and desorption in bread crust.
Main Methods:
- Employed two distinct water sorption experiments: an oscillatory sorption test and a stepwise relative humidity (RH) increase test.
- Analyzed adsorption and desorption dynamics using time-dependent kinetic models.
- Determined water uptake rate parameters (k) and time-dependence parameters (C).
Main Results:
- Oscillatory sorption test dynamics were described by a single exponential function.
- A peak in water uptake rate (k) was observed at 50-70% RH.
- Rate parameters from stepwise RH experiments were approximately 10 times lower than those from oscillatory tests, with parameter C comparable to isotherm experiment rates.
Conclusions:
- The study successfully proposed a method for evaluating bread crust water sorption kinetics.
- Different experimental timescales significantly impact measured water uptake rates.
- Multiple relaxation processes occur simultaneously in bread crust during water uptake.
Related Concept Videos
02:34Water and Mineral Acquisition
Specialized tissues in plant roots have evolved to capture water, minerals, and some ions from the soil. Roots exhibit a variety of branching patterns that facilitate this process. The outermost root cells have specialized structures called root hairs that increase the root surface, thus increasing soil contact. Water can passively cross into roots, as the concentration of water in the soil is higher than that of the root tissue. Minerals, in contrast, are actively transported into root cells.
00:47Osmosis
Approximately 60% to 95% of the weight of living organisms is attributed to water. Therefore, maintaining appropriate water balance within cells is of paramount importance. Osmosis is the movement of water across a semipermeable membrane, such as a cell’s plasma membrane. In living organisms, water plays a crucial role as a solvent—a molecule that dissolves other molecules.Diffusion Versus OsmosisBoth diffusion and osmosis are types of passive transport—cellular transport that does not require...
01:30Osmosis
Osmosis is the movement of free water molecules through a semipermeable membrane. The water's concentration gradient across the membrane is inversely proportional to the solutes' concentration. Whereas diffusion transports material across membranes and within cells, osmosis transports only water across a membrane, and the membrane limits the diffusion of solutes in the water. Osmosis is a special case of diffusion.
Water, like other substances, moves from a high concentration of free water...
Water, like other substances, moves from a high concentration of free water...
02:03Xylem and Transpiration-driven Transport of Resources
The xylem of vascular plants distributes water and dissolved minerals that are taken up by the roots to the rest of the plant. The cells that transport xylem sap are dead upon maturity, and the movement of xylem sap is a passive process.
01:46The Apoplast and Symplast
Plant growth depends on its ability to take up water and dissolved minerals from the soil. The root system of every plant is equipped with the necessary tissues to facilitate the entry of water and solutes. The plant tissues involved in the transport of water and minerals have two major compartments - the apoplast and the symplast. The apoplast includes everything outside the plasma membrane of living cells and consists of cell walls, extracellular spaces, xylem, phloem, and tracheids. The...
00:53Tonicity in Plants
Tonicity describes the capacity of a cell to lose or gain water. It depends on the quantity of solute that does not penetrate the membrane. Tonicity delimits the magnitude and direction of osmosis and results in three possible scenarios that alter the volume of a cell: hypertonicity, hypotonicity, and isotonicity. Due to differences in structure and physiology, tonicity of plant cells is different from that of animal cells in some scenarios.Plants and Hypotonic EnvironmentsUnlike animal cells,...