Thesis (MSc)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Pasta manufacturing is a process whereby wheat flour is converted into a shelf-stable food that is
more desirable than native wheat flour. It can be fortified and may serve as a valuable source of
nutrition in developing countries. Quality measures are of importance in the production process to
ensure a consistent and acceptable finished product.
Literature provides information on many aspects of wheat types, milling techniques and processing
of pasta. Protein content and quality of cultivated wheat varieties is of major importance to
produce quality pasta products. Wheat types of lower protein content are more readily available
than traditionally used durum wheat. As in all food products, the cost of final products is of major
importance. Bread wheat is generally less expensive than durum wheat. However, product quality
(and thus acceptability) may be lower. Direct measurements of product quality are currently limited
to protein content, moisture content, colour analyses and certain other characteristics measurable
in a laboratory, for example mechanical strength and firmness. Direct measurements of defects
that may affect final product quality, such as cracks and fissures on the strands of spaghetti,
different types of spots and lines on the strands, broken units, units sticking together and odd
shapes are not well documented.
During the first part of this study, spaghetti quality evaluation techniques were reviewed, improved
or developed and thereafter standardised. This developmental research was conducted to
establish valid and reliable measures (with a high degree of repeatability) for the evaluation of dry
and cooked pasta quality characteristics. A wide variety of available products on the South African
market were evaluated for different quality characteristics. From this evaluation standards were
drawn up, tested for validity and reliability by means of repeatability. Minimum sample sizes for the
evaluation of different quality characteristics were calculated and presented in the study, together
with reference photographs that can be used to evaluate spaghetti. This study found that colour evaluation by means of commercially available apparatus needs
revision. This study suggests the use of multiple layers when evaluating translucent food products
for colour. The occurrence of fissures and flour spots are of importance for the quality of the final
product. This study provides a set of valid and reliable measurements for measuring the quality of
dry and cooked spaghetti. Simple techniques can therefore be used to detect the presence or
absence of these defects.
Thereafter an empirical study was conducted to describe the differences between spaghetti
prepared from durum and non-durum wheat, dried at different temperatures and at different relative
humidity. Spaghetti samples of diverse perceived quality, from different manufacturers, were
purchased and evaluated. Standard methods and the newly developed testing methods were used
to test whether these methods effectively distinguish between spaghetti of diverse quality,
reflecting on the validity of the methods. Correlations were calculated between dependent and
independent variables in an attempt to find possible explanations for certain defects or quality
differences, and to test certain theories in the literature.
Certain relationships between quality characteristics were found, while others were questioned.
The most important proven relationships were between protein content and its effects on reducing
quality defects such as fissures, breakages and cooking losses. The relationship between ash
content and spaghetti colour could not be confirmed in this study. This study confirmed that
protein remains one of the most important variables to ensure consistent quality spaghetti. / AFRIKAANSE OPSOMMING: Pastavervaardiging is ‘n proses waartydens koring meel omskep word in a produk met ‘n stabiele
en lang rakleeftyd wat meer gewens is as die oorspronklike koring meel. Pasta kan gefortifiseer
word and kan dien as a waardevolle voedingsbron in ontwikkelende lande. Om ‘n konstante en
aanvaarbaare finale produk te verseker is kwaliteitmetings gedurende die produksie proses
belangrik.
Die literatuur voorsien heelwat inligting rakende aspekte van belang vir pastakwaliteit, byvoorbeeld
koringtipes, maaltegnieke en die vervaardigingsproses. Proteïninhoud en die kwaliteit daarvan is
van groot belang tydens die produksie van hoë kwaliteit pasta. Koringtipes met ‘n laer
proteïninhoud is meer geredelik beskikbaar as tradisionele durumkoring. Soos met alle
voedselprodukte, is die koste van die finale produk van groot belang. Oor die algemeen verhandel
broodkoring teen laer pryse as durumkoring. Die produkkwaliteit en aanvaarbaarheid van pasta
vervaardig van broodkoring kan egter laer wees as dié van durumkoring. Direkte metings van
produkkwalitiet is tans beperk tot proteïninhoud, voginhoud, kleuranalise en sekere eienskappe
meetbaar in ‘n laboratorium, byvoorbeeld meganiese sterkte en fermheid. Die direkte meting van
defekte wat finale produkkwaliteit kan beïnvloed, byvoorbeeld barste, krake, meel kolletjies, strepe
op spaghetti-eenhede, gebreekte eenhede, eenhede wat aan mekaar kleef en ongewone vorms, is
nie goed gedokumenteer nie.
Gedurende die eerste gedeelte van hierdie studie, is ‘n oorsig van spaghetti evaluasie tegnieke
beskikbaar in die literatuur gdoen, waarna sekeres verbeter is, ander ontwikkel is en finaal
gestandariseer is. Hierdie navorsing is uitgevoer om geldige en betroubare metings (met ‘n hoë
graad van herhaalbaarheid) vir die evaluasie van droë- en gaar pastakwalitietseienskappe vas te
stel. ‘n Wye verskeidenheid van produkte beskikbaar op die Suid-Afrikaanse mark is ge-evalueer
ten opsigte van verskillende kwaliteitseienskappe. Vanuit hierdie evaluasies is standaarde
saamgestel en getoets vir geldigheid en betroubaarheid deur middel van herhaalbaarheid. ‘n
Minimum steekproefgrootte per kwaliteitseienskap is bereken en word vermeld in hierdie studie.
Daarmeesaam word verwysingsfoto’s aangebied wat gebruik kan word tydens die evaluasie van spaghetti. Hierdie studie bied a stel geldige en betroubare meting vir die kwaliteit van droe en
gaan spaghetti. Eenvoudige tegnieke kan dus gebruik word om die voorkoms van hierdie defekte
te meet.
Met afloop van die verkennende studie, is ‘n empiriese studie gedoen om die verskille te beskryf
tussen pasta vervaardig van durum en brood koring, gedroog teen verskillende temperature en
relatiewe humiditeit. Spaghettimonsters met oënskynlike diverse kwaliteit, vervaardig deur
verskillende maatskappye, is aangekoop en ge-evalueer. Standaardmetings en nuutontwerpte
metings is gebruik om te bevestig of die metings kan onderskei tussen spaghetti met
uiteenlopende kwaliteit, wat reflekteer op die geldigheid van die metingsmetodes. Korrelasies is
bereken tussen afhanklike en onafhanklike veranderlikes in ‘n poging om moontlike verklarings vir
sekere defekte of kwaliteitsverskille te vind, en ook om sekere teoriëe in die literatuur te toets.
Die verband tussen sekere kwaliteitseienskappe is bevestig en bewys, terwyl ander bevraagteken
was. Die mees belangrike verband was proteïninhoud en die effek daarvan om die voorkoms van
defekte, soos barste, gebreekte eenhede en kookverliese te verlaag. Die verband tussen
asinhoud en spaghettikleur kon nie in hierdie studie bevestig word nie.
Hierdie studie het bevestig dat proteïn die mees belangrike veranderlike is wat oorweeg moet word
wanneer ‘n konstante hoë kwaliteit spaghettiproduk vervaardig word. Kleurevaluasie met behulp
van kommersieel-beskikbare apparaat vereis hersiening. Hierdie studie stel voor dat tydens kleur
evaluasie van voedsel wat lig deurlaatbaar is, dit in veelvoudige lae evalueer moet word. Die
voorkoms van defekte soos barste, krake of meel kolletjies is van belang ten opsigte van finale
produkkwaliteit. Hierdie studie bied riglyne vir die evaluasie van die genoemde defekte. Die
voorkoms van hierdie defekte is van groter belang as die graad waarteen die defek voorkom.
Eenvoudige tegnieke kan vervolgens gebruik word om die teenwoordigheid of afwesigheid van
hierdie defekte te bepaal.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/16613 |
| Date | 04 1900 |
| Creators | MacGregor, Elizabeth |
| Contributors | Vosloo, M.C., Vorster, S.H., University of Stellenbosch. Faculty of Agrisciences. Dept. of Consumer Science. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 161 leaves : ill. |
| Rights | University of Stellenbosch |
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