Fate of hydroxyapatite nano particles during in vitro gastrointestinal digestion : a thesis presented in partial fulfilment of the requirements for the degree of Master in Food Technology at Massey University, Riddet Institute and Massey Institute of Food Science and Technology, Palmerston North, New Zealan
Loading...
Date
2018
DOI
Open Access Location
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Massey University
Rights
The Author
Abstract
There is an increasing change in population demographics towards an aging
population in the world, which had led to the availability of various commercial
nutritionally supplemented products. Hydroxyapatite (HA), with chemical
formula Ca10(PO4)6(OH)2, is an insoluble calcium salt used for calcium
supplementation because of its similarity to the minerals found in human bone
and teeth. The insoluble calcium salts are preferred over the soluble ones because
of their high heat stability during milk processing under high heat treatment.
However, the drawback of insoluble calcium salts is the tendency to sediment
during storage resulting in unfavourable gritty texture. Thus, reduction in particle
sizes into micron to nano-size improves the dispersion of these insoluble salts.
However, the application of nano-sized particles in food products have raised
concerns from both the regulatory organizations and consumers on the
implications related to both the environmental and health safety aspects. Thus,
the objective of the study is to determine the digestion behaviour of nano-sized
needle/rod shaped HA (nHA) when added into skim milk during in vitro
gastrointestinal digestion. Determination of calcium such as soluble and ionic
calcium was conducted to determine the dissolution of nHA. The structural
changes and the crystallographic changes of nHA were determined using electron
microscopy and x-ray diffraction techniques. The results of in vitro gastric
digestion showed presence of undissolved nHA particles even after 240 min of
gastric and 120 min of intestinal digestion when examined under TEM, while the
XRD analysis detected the presence of crystalline nHA in the first 120 min of
gastric digestion. Thus, the possible mechanisms leading to the incomplete
dissolution of nHA under acidic conditions of the stomach are discussed
subsequently.
Description
The following figures have been removed for copyright reasons, but may be accessed through their sources listed in the References:
Figures 2.2 (Yada et al., 2014, Fig.1), 2.3 (Rivera-Munoz, 2011), 2.4 (Sakae et al., 2015, Fig. 2 & 3), 2.5 (Ehrlich et al., 2009, Fig. 3), 2.6 (Lynn & Bonfield, 2005, Fig. 1), 2.7 (Ehrlich et al., 2009, Fig. 6), 2.8 (Mafé et al., 1992, Fig. 1), 2.9 (Gaucheron et al., 2005, Fig. 2). Composite Figure 2.10 remains for clarity's sake.
Keywords
Hydroxyapatite, Solubility, Food additives, Biotechnology, Skim milk, Digestion