Joe M. Regenstein
Received: 26 February 2017 /Accepted: 8 May 2017 /Published online: 15 May 2017
Springer Science+Business Media New York 2017
Abstract Calcium is one of the most important elements in
the human body. Insoluble calcium particles are often used in
calcium-fortified food products, such as calcium-fortified
milk, dairy beverages or protein powders. However, their sus-
pension may be unstable often leading to precipitation in such
products. In this study, three different kinds of insoluble cal-
cium particles, i.e. hydroxyapatite (HA), tricalcium phosphate
(TCP) and calcium carbonate (CaCO
phiphilic phospholipids using a solvent-exchange method.
Suspension stability of these insoluble calcium particles was
effectively improved with phospholipid coating, especially for
HA and TCP, as more phospholipids were coated on the sur-
face of these two calcium particles than CaCO
coating increased the electrostatic repulsions between parti-
cles, preventing the particles from aggregating and precipitat-
ing. In addition, the digestibility of phospholipid-coated insol-
uble calcium particles was tested in simulated gastric juice,
and the dissolution time of these insoluble calcium particles
was prolonged through phospholipid coating.
Calcium is one of the most important elements in the human
body, regulating a series of physiological and biochemical
functions [1–3]. Calcium-fortified foods are popular, especial-
ly dairy products. Insoluble calcium supplements have been
used to produce calcium-fortified milk and dairy beverages, as
they do not affect the heat stability of dairy proteins unlike
soluble calcium salts [2, 4, 5]. However, insoluble calcium
supplements are often unstable leading to precipitates.
Addition of stabilizers is feasible, but may raise the cost and
spoil the taste. As a result, there is a need to develop new
methods to improve the stability of calcium-fortified foods.
Proteins have been one of the most commonly used stabi-
lizers. For example, Tercinier and coworkers studied the ad-
sorption of milk proteins onto hydroxyapatite (HA) particles
and the subsequent improvement of suspension stability [3, 6,
7]. Wen et al. found that small amount of adsorbed protein
would decrease the stability of insoluble calcium suspensions,
and a critical concentration of protein was needed to stabilize
the suspension .
In addition to being an important component of cell mem-
branes, phospholipids are also biomolecules with potential
applications in human nutrition and medicine [9–11].
Phospholipids are amphiphilic molecules and are often used
as surfactants in dairy products such as infant formula emul-
sions and milk powders. For infant formula emulsions the
addition of lecithin decreased interfacial tension between the
oil and aqueous phases, and improved the emulsion stability
as well as oxidative stability [12, 13]. Adding soy lecithin to
milk powder before spray drying can improve the wettability
and solubility of such product [14, 15]. When considering the
surfactant properties, biological safety and nutritional value,
the application of phospholipids to increase the stability of
suspensions of insoluble calcium particles might be feasible.
Electronic supplementary material The online version of this article
(doi:10.1007/s11483-017-9484-5) contains supplementary material,
which is available to authorized users.
* Peng Zhou
State Key Laboratory of Food Science and Technology, Jiangnan
University, Wuxi, Jiangsu Province 214122, People’s Republic of
Department of Food Science, Cornell University,
Ithaca, NY 14853-7201, USA
Food Biophysics (2017) 12:279–288
Enhancement of the Stability of Insoluble Calcium Particles Using
a Phospholipid Coating