Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The presence of mineral oils in dry foodstuff was found to originate from the packaging materials, namely,
paperboard manufactured from recovered fibres, and these oils subsequently migrate to the foodstuff via
the vapour phase. The presence of mineral oils in food is of concern as it originates from the use of paper
products not originally intended for food contact applications, i.e., before the paper is subjected to a
suitable recycling process. These mineral oils consist of technical grade compounds which may contain
aromatic compounds and other components with unknown toxicological effects. Although the related
authorities are currently considering the safe and legal limits of these contaminants in foodstuffs, as well
as establishing a standardised test method for monitoring mineral oils in food and packaging materials,
paperboard manufacturers wish to ensure that their products are safe for food contact applications. Since
recycling is unavoidable, particularly from an ecological and economical point of view, one of the
proposed solutions the industry is focussing on is the use of a functional barrier towards mineral oils – be
it an inner bag as a direct food-contact surface, or a barrier coating directly applied on the inner side of
the paperboard.
In this study, a permeation test method was established, and developed, to evaluate the
transmission rate of a volatile organic compound, acting as a mineral oil simulant, through model paper
and plastic packaging materials. This was correlated to the transmission rate of actual mineral oil through
the packaging materials, and therefore used as a highly accelerated tool to characterise packaging
materials in relation to their barrier properties. The test method, referred to as the “heptane vapour
transmission rate,” was subsequently used to derive the required transport parameters’ characteristics of
each of the tested materials, which enabled an evaluation of the potential shelf-life of the packaged
product. This research demonstrated that barrier-coated paperboards have the ability to behave in the
same way as, and often even better than, commercial plastic films, towards the migration of mineral oil.
Detailed information on the interaction between the packaging materials and mineral oil simulant,
n-heptane, was acquired from gravimetric sorption. Insight was obtained into a material’s ability to
function as a mineral oil barrier. It was established that the quick and easy permeation method was
sufficient for evaluating packaging materials as potential mineral oil barriers, and resulted in the
determination of transport parameters that were higher than that obtained by sorption. The obtained
transport parameters could therefore be considered a worst case scenario when predicting the package
content shelf-life. / AFRIKAANSE OPSOMMING: Daar is voorheen bevind dat die teenwoordigheid van mineraalolies in droë voedsel afkomstig is van die
verpakkingsmateriaal, naamlik karton, wat vervaardig is van herwonne papierprodukte, en daarna
migreer die olies na die voedsel deur die gasfase. Die teenwoordigheid van hierdie mineraalolies in kos
wek groot kommer aangesien dit afkomstig is van papierprodukte wat nie oorspronklik bedoel is vir
voedselkontak voor die herwinningsproses nie. Die olies bestaan uit industriële graad mineraalolies wat
moontlik aromatiese verbindings asook ander komponente bevat waarvan die toksiekologiese effekte
onbekend is. Terwyl die betrokke owerhede tans besig is om die veilige en wettige grense van hierdie
kontaminante in voedsel te oorweeg, asook die vestigting van 'n gestandaardiseerde toetsmetode vir die
kontrole van mineraalolies in die voedsel-verpakkingsmateriaal-kombinasie, wil karton- en
papiervervaardigers graag verseker dat hul produkte veilig is vir voedselkontak. Siende dat herwinning
onvermydelik is vanuit 'n ekologiese en ekonomiese oogpunt, is een van die voorgestelde oplossings in
die bedryf om te fokus op die gebruik van 'n funksionele keerfilm ten opsigte van mineraalolies, wat ‘n
sakkie binne-in die karton, wat dien as die direkte kos-kontakoppervlak, of 'n keerlaag, wat direk
aangewend word op die binnekant van die karton, kan behels.
Hierdie studie ondersoek die daarstel en deursypelingsontwikkeling van 'n toetsmetode om die
oordragtempo van 'n vlugtige organiese verbinding, wat optree as 'n mineraalolie simulant, deur middel
van model papier- en plastiekverpakkingsmateriale, te evalueer. Dit stem ooreen met die oordragtempo
van werklike mineraalolies deur die verpakkingsmateriaal en kan dus gebruik word as 'n hoogs versnelde
instrument om verpakkingsmateriale te karakteriseer met betrekking tot hul keereienskappe. Die
toetsmetode, die sogenaamde "heptaangasoordragtempo," is vervolgens gebruik om die vereiste
oordragparameters af te lei wat kenmerkend is van elk van die geëvalueerde verpakkingsmateriale en
wat sodoende gebruik kon word om die potensiële raklewe van die verpakte produk te bepaal. Hierdie
navorsing het getoon dat kartonprodukte met ‘n keerlaag die vermoë het om dieselfde op te tree as
kommersiële plastiekfilms en dikwels selfs beter, ten opsigte van die migrasie van mineraalolies.
Gedetailleerde inligting oor die interaksie tussen die verpakkingsmateriale en mineraalolie
simulant, n-heptaan, is verkry vanaf gravimetriese sorpsie. Dit gee insig in 'n materiaal se vermoë om te
funksioneer as 'n mineraalolie-keermiddel. Daar is vasgestel dat die vinnige en maklike deurwerking
metode voldoende is vir die evaluering van verpakkingsmateriale as potensiële mineraalolie-keermiddels,
en verleen oordragparameters wat hoër is as dié verkry deur sorpsie. Hierdie oordragparameters kan dus
as 'n ergste scenario vir die voorspelling van die raklewe van ‘n verpakte produk beskou word.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/20269 |
| Date | 03 1900 |
| Creators | Tiggelman, Ineke |
| Contributors | Pasch, H., Hartmann, P. C., Stellenbosch University. Faculty of Science. Dept. of Chemistry and Polymer Science. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Rights | Stellenbosch University |
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