Thesis (MSc Food Sc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Hectolitre mass (HLM) measurements allow rapid and accurate determination of grain
density. HLM devices from different countries (Australia, Canada, France, Germany,
South Africa, the United Kingdom and the United States of America [USA]) have been
investigated for their effect on the HLM measurements of oats. In addition, the potential
of near infrared (NIR) hyperspectral imaging has been evaluated to distinguish between
oat samples with different HLM values. Comparing HLM measurements obtained from
the respective devices, the USA and the South African devices resulted in significantly
(P<0.05) lower HLM values compared to the other devices where as the German device
resulted in higher values (P<0.05) than the other devices. HLM values from all the
devices were highly correlated with intra-class correlation (ICC) consistency values of at
least 0.90. These high correlations would allow direct replacement of the South African
device with any of the other devices. The equipment selected as replacement should
ideally be calibrated according to the ISO 7971-3 standard (i.e. the device currently
used in Germany).
HLM values significantly (P<0.05) increased when oat samples were rubbed before
measurements were made, indicating the importance of continuation of this sample
preparation step. The investigation on the effect of the operator on HLM determinations
showed that the unskilled operator measured HLM values significantly different to those
obtained by the skilled operator. This emphasises the importance of training in spite of
HLM measurements being a simple procedure.
A poor correlation (r = 0.18) was found between protein content and HLM values of
oat samples. Moisture content significantly affected the HLM values of oats and results
clearly showed a decrease in HLM values with increasing moisture content. Scanning
electron microscope (SEM) micrographs revealed that the starch granules became
swollen and that they increased in size with an increase in moisture content, resulting in
a decrease in HLM. NIR hyperspectral imaging offers the testing of individual grains
non-destructively. This is often required by plant breeders because they subsequently
need to plant selected grains. NIR offers this option to plant breeders. NIR
hyperspectral imaging, which combines NIR spectroscopy with digital imaging, was
used to distinguish between six oat samples with varying HLM values. NIR
spectroscopic differences were observed between the images of the two samples with
the highest and lowest HLM values (60.2 and 49.35 kg.hL-1). Less distinct differences
were observed in the NIR hyperspectral images of two samples differing by less than
2.0 kg.hL-1. Although mixed oat samples were used, these preliminary results established the
possible use of NIR hyperspectral imaging in evaluating oat samples from breeding
trials. The use of this technique could also be extended to evaluation of other quality
characteristics of oats. / AFRIKAANSE OPSOMMING: Hektolitermassa- (HLM-)metings maak snelle en akkurate bepaling van korreldigtheid
moontlik. HLM-toestelle van verskillende lande (Australië, Kanada, Frankryk, Duitsland,
Suid-Afrika, die Verenigde Koninkryk en die Verenigde State van Amerika) is ondersoek
vir hulle uitwerking op die HLM-metings van hawer. Daarby is die potensiaal van nabyinfrarooi-
(NIR-)hiperspektrale beelding geëvalueer om tussen hawermonsters met
verskillende HLM-waardes te onderskei. Tydens vergelyking van HLM-metings verkry
van die onderskeie toestelle, het die Amerikaanse en die Suid-Afrikaanse toestelle
beduidend (P<0.05) laer HLM-waardes opgelewer in vergelyking met die ander toestelle
terwyl die Duitse toestel hoër waardes (P<0.05) as die ander toestelle getoon het. Daar
was hoë korrelasies tussen die HLM waardes verkry van die apparate met
intraklaskorrelasie (IKK) konsekwentheidwaardes van ten minste 0.90. Hierdie hoë
korrelasies sou direkte vervanging van die Suid-Afrikaanse toestel met enige van die
ander toestelle moontlik maak. Die toerusting gekies as vervanging sou ideaal gesproke
in ooreenstemming met die ISO 7971-3 standaard gekalibreer kon word (bv. die toestel
wat tans in Duitsland gebruik word).
HLM-waardes het beduidend (P<0.05) verhoog toe hawermonsters gevryf is voor
metings gemaak is, wat dui op die belang van verlengde gebruik van hierdie stap
tydens die voorbereiding van monsters. Die ondersoek na die uitwerking van die
operateur op HLM-bepalings het getoon dat die onervare operateur HLM-waardes
beduidend verskillend gemeet het teenoor dié verkry deur die ervare operateur. Dit
beklemtoon die belang van opleiding ten spyte daarvan dat HLM-metings ’n eenvoudige
prosedure is.
’n Swak korrelasie (r = 0.18) is aangetref tussen proteïeninhoud en HLM-waardes
van hawermonsters. Voginhoud het die HLM-waardes van hawer beduidend beïnvloed
en resultate het duidelik ’n styging in HLM-waardes met verhoging van die voginhoud
getoon. Aftaselektronmikroskoop- (AEM-)mikrobeelde het aangedui dat die
styselgranules swel en in grootte toeneem met verhoging van die voginhoud, wat
aanleiding gee tot ’n verlaging in HLM. NIR-hiperspektrale beelding maak die toets van
individuele korrels op niedestruktiewe wyse moontlik. Dit word dikwels deur
plantkwekers vereis aangesien hulle na toetsing uitgesoekte korrels moet plant. Nabyinfrarooi
bied hierdie opsie aan plantkwekers. NIR-hiperspektrale beelding, wat NIRspektroskopie
met digitale beelding kombineer, is gebruik om te onderskei tussen ses
hawermonsters met wisselende HLM-waardes. NIR-spektroskopiese verskille tussen die beelde van die twee monsters met die hoogste en laagste HLM-waardes (60.2 en
49.35 kg.hL-1) is waargeneem. Minder duidelike verskille is in die NIR-hiperspektrale
beelde van twee monsters wat met minder as 2.0 kg.hL-1 verskil het, waargeneem.
Alhoewel gemengde hawermonsters gebruik is, het hierdie voorlopige resultate die
moontlike gebruik van NIR-hiperspektrale beelding by die evaluering van
hawermonsters van kweekproewe vasgestel. Die gebruik van hierdie tegniek sou ook
uitgebrei kon word tot die evaluering van ander kwaliteitseienskappe van hawer.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/20093 |
| Date | 03 1900 |
| Creators | Emvula, Sakeus |
| Contributors | Manley, Marena, Stellenbosch University. Faculty of AgriSciences. Dept. of Food Science. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 139 p. : ill. |
| Rights | Stellenbosch University |
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