Thesis (MScAgric)--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: Although kudu (Tragelaphus strepsiceros) and impala (Aepyceros melampus) are found in the
same geographical area, there is variation in their diets as kudu are predominantly browsers,
feeding on tree and shrub leaves, while impala are known as mixed feeders as they graze
and browse. Therefore this poses the question whether the diet would influence their meat
quality. The objective of this investigation was to evaluate the physical measurements and
chemical composition of M. longissimus dorsi, M. biceps femoris, M. semimembranosus, M.
semitendinosus and M. supraspinatus for kudu and impala, two southern African antelope
species. The effects of age (adult and sub-adult) and gender (male and female) were also
determined. The sensory characteristics of the M. longissimus dorsi muscle for sub-adult
kudu and impala were investigated. Correlations between the various physical
measurements and chemical composition of the meat were verified. Physical measurements
and chemical composition of the M. longissimus dorsi muscle were tested for correlations with
the sensory ratings of the meat.
Dressing percentage of impala (59.88%) (n=28) was higher than that of kudu (57.60%) (n=35).
The main effects (species, gender and age) showed no differences for drip loss and cooking
loss. However, muscles differed in terms of cooking loss with impala M. semitendinosus
having the highest (38.28%) value and kudu M. longissimus dorsi having the lowest value
(30.77%). For impala, the highest Warner–Bratzler shear (WBS) values were measured for M.
semimembranosus (5.90 kg/1.27cmø), followed by M. biceps femoris, M. longissimus dorsi,
and M. semitendinosus with the lowest WBS values measured for M. supraspinatus (3.61
kg/1.27cmø). All impala muscles had lower L* values and appeared darker in colour than
kudu muscles, except for M. supraspinatus. Adult animals also had lower L* values than the
sub-adult group. Kudu had significantly higher a* and b* values (more red) than impala.
Chroma values were higher for kudu, thus appearing brighter in colour. The respective
muscles of kudu and impala investigated differed significantly in terms of physical
characteristics. However, gender and age did not have an effect on the physical
measurements.
Moisture content was higher in kudu meat (76.46%) than in impala meat (75.28%). Muscles
differed for both moisture and fat content. The highest fat was found in M. supraspinatus
followed by M. biceps femoris, M. semitendinosus, M. semimembranosus and M. longissimus
dorsi. Protein content did not differ between species (kudu: 21.66%; impala: 22.26%), gender
(male: 21.98%; female: 21.95%) and age groups (adult: 21.74%; sub-adult: 22.18%). Kudu M.
longissimus dorsi (1.62%) had lower fat content than impala M. longissimus dorsi (2.22%) and
female animals had a higher fat content than male animals. Sub-adults (1.20 ± 0.02%) had
higher ash content than adults (1.10 ± 0.03%). The M. supraspinatus had the lowest protein and also the highest fat content, with M. semimembranosus having the lowest fat content but
the highest value for protein.
Myoglobin content did not differ between species, although females had higher (6.58 ± 0.20
mg/g) myoglobin content than males (5.11 ± 0.25 mg/g). Glycolitic muscles had the lowest
myoglobin content with the highest values found in M. supraspinatus, an oxidative muscle.
An interaction was noted between species and muscle for myoglobin content. Myoglobin
content in impala M. longissimus dorsi was higher than that in kudu M. longissimus dorsi;
however for all other muscles the myoglobin content was lower in impala.
Gender did not affect mineral content. Potassium levels were highest for kudu while
phosphorus was more prevalent in impala meat. Adult and sub-adult groups differed in terms
of potassium, calcium and zinc content. Potassium and calcium content were higher for subadult
animals while zinc content was higher in adult animals.
In impala meat, stearic acid (22.67%) was the major fatty acid, followed by palmitic acid
(16.66%). In contrast, oleic acid (24.35%) was the most profuse fatty acid in kudu, followed
by linoleic acid (22.95%). The SFA’s as a percentage of the total fatty acids differed between
impala (51.12%) and kudu meat (34.87%). Kudu meat had a higher concentration of total
PUFA (38.88%) than impala (34.06%) meat. The PUFA: SFA ratio for kudu meat (1.22) was
more favourable than that for impala meat (0.73). The ratio of n-6 PUFA’s to n-3 PUFA’s for
kudu and impala were determined as 2.22 and 3.76 respectively. From the current findings it
is evident that kudu and impala meat have advantageous fatty acid profiles and can be a
healthy substitute for other red meats.
Kudu meat (72.62 ± 1.86 mg/100g) had higher cholesterol than impala meat (55.35 ± 1.84
mg/100g). It is recommended that further studies be done in order to confirm the cholesterol
content of kudu meat.
Within species, no gender differences for any of the sensory characteristics tested were noted.
The impala meat had a more intense game aroma than the kudu meat, while kudu meat was
found to be more juicy than impala meat. It can therefore be concluded that the marketing of
game meat should be species-specific as there are distinct flavour and aroma differences
between kudu and impala meat. / AFRIKAANSE OPSOMMING: Alhoewel koedoes (Tragelaphus strepsiceros) en rooibokke (Aepyceros melampus) in
dieselfde geografiese area voorkom, is daar variasie in hulle diëte. Koedoes is hoofsaaklik
blaarvreters, terwyl rooibokke bekend staan as gemengde vreters aangesien hulle grassowel
as blaarvreters is. Die vraag ontstaan dus of die verskil in diëet die kwaliteit van hulle
vleis sal beϊnvloed. Die doel van hierdie ondersoek was dus om die fisiese metings en
chemiese samestelling van die M. longissimus dorsi, M. biceps femoris, M.
semimembranosus, M. semitendinosus en M. supraspinatus vir koedoes en rooibokke te
bepaal. Die invloed van ouderdom (volwasse en onvolwasse) en geslag (manlik en vroulik)
op hierdie eienskappe is ook geëvalueer. Die sensoriese eienskappe van die M. longissimus
dorsi van onvolwasse koedoes en rooibokke is ook ondersoek. Korrelasies tussen die fisiese
metings en chemiese samestelling van die vleis is ondersoek. Die fisiese metings en
chemiese samestelling van die M. longissimus dorsi is getoets vir korrelasies met die
resultate van die sintuiglike evaluering van die vleis.
Die gemiddelde uitslagpersentasie van rooibokke (59.88%) (n=28) was hoër as die van
koedoes (57.60%) (n=35). Daar was geen verskille in drupverlies en kookverlies vir die
hoofeffekte (spesie, geslag en ouderdom) nie. Spiere het wel verskil in terme van kookverlies,
met die hoogste waarde gemeet vir rooibok M. semitendinosus (38.28%) en die laagste
waarde vir koedoe M. longissimus dorsi (30.77%). In rooibokke was die hoogste Warner-
Bratzler skeurkrag waardes gemeet vir M. semimembranosus (5.76 kg/1.27cmø), gevolg deur
M. biceps femoris, M. longissimus dorsi, en M. semitendinosus met die laagste Warner-
Bratzler skeurkrag waardes gemeet vir M. supraspinatus (3.78 kg/1.27cmø). Alle
rooibokspiere het laer L* waardes gehad en was donkerder van kleur as koedoespiere,
behalwe vir M. supraspinatus. Laer L* waardes is ook verkry vir volwasse diere in
vergelyking met onvolwasse diere. Die a* en b* waardes was hoër in koedoe- as in
rooibokvleis, m.a.w. koedoevleis het rooier vertoon. Die onderskeie koedoe- en rooibokspiere
het betekenisvol verskil in terme van fisiese eienskappe, terwyl geslag en ouderdom geen
effek op die fisiese eienskappe gehad het nie.
Voginhoud was hoër in koedoe- (75.52%) as in rooibokvleis (74.52%). Verkille tussen spiere
is opgemerk vir beide vog- en vetinhoud. M. supraspinatus het die hoogste vetinhoud gehad,
gevolg deur M. biceps femoris, M. semitendinosus, M. semimembranosus en M. longissimus
dorsi. Geen verskille is opgemerk tussen spesies (koedoe: 21.66%; rooibok: 22.26%),
geslagte (manlik: 21.98%; vroulik: 21.95%) en ouderdomme (volwasse: 21.74%; onvolwasse:
22.18%) in terme van proteϊeninhoud nie. Die vetinhoud van koedoe M. longissimus dorsi
(1.62%) was laer as dié van rooibok M. longissimus dorsi (2.22%) en die vetinhoud van
vroulike diere was hoër as dié van manlike diere. Onvolwasse diere (1.20 ± 0.02%) het ‘n
hoër asinhoud as dié van volwasse diere (1.10 ± 0.03%) getoon. In terme van die onderskeie spiere het M. supraspinatus die laagste proteϊen- en die hoogste vetinhoud gehad, terwyl M.
semimembranosus die laagste vet- en die hoogste proteϊeninhoud gehad het.
Die mioglobieninhoud was nie beϊnvloed deur spesie nie, terwyl vroulike diere ‘n hoër (6.58 ±
0.20 mg/g) mioglobieninhoud as manlike diere (5.11 ± 0.25 mg/g) gehad het. Die M.
supraspinatus, ‘n oksidatiewe spier het die hoogste mioglobieninhoud gehad, terwyl
glikolitiese spiere die laagste mioglobieninhoud gehad het. ’n Interaksie tussen spesie en
spier was opgemerk vir mioglobieninhoud. Rooibok M. longissimus dorsi het ‘n hoër
mioglobieninhoud as koedoe M. longissimus dorsi gehad, terwyl die mioglobieninhoud vir al
die ander spiere laer was in rooibokke.
Mineraalinhoud was nie deur geslag beϊnvloed nie. Kaliumvlakke was hoër in koedoevleis,
terwyl fosforvlakke hoër was in rooibokvleis. Kalium- en kalsiuminhoud was hoër in
onvolwasse diere terwyl die sinkinhoud hoër was in volwasse diere.
Steariensuur (22.67%), gevolg deur palmitiensuur (16.66%) was die mees algemene vetsure
in rooibokvleis. In teenstelling hiermee was oleϊensuur (24.35%), gevolg deur linoleϊensuur
(22.95%) die mees algemene vetsure in koedoevleis. Die totale versadigde vetsure was laer
in koedoevleis (34.87%) in vergelyking met rooibokvleis (51.12%), terwyl die totale polionversadigde
vetsure in koedoevleis (38.88%) hoër was as dié van rooibokvleis (34.06%).
Die verhouding van n-6 tot n-3 poli-onversadigde vetsure vir koedoe en rooibok was 2.22 en
3.76 onderskeidelik. Hierdie resultate bevestig dat koedoe- en rooibokvleis oor ‘n
vetsuurprofiel beskik wat ’n gesonde alternatief bied tot ander rooivleise.
Die cholesterolinhoud van koedoevleis (72.62 ± 1.86 mg/100g) was hoër as dié van
rooibokvleis (55.35 ± 1.84 mg/100g). Dit word egter aanbeveel dat verdere studies gedoen
word om die cholesterolinhoud van koedoevleis te bevestig.
Binne spesies was daar geen geslagsverkille vir enige van die sensoriese eienskappe nie.
Rooibokvleis het ‘n meer intense wildsvleis aroma as koedoevleis gehad, terwyl koedoevleis
meer sappig was as rooibokvleis. Hierdie resultate dui daarop dat die bemarking van
wildsvleis spesie-spesifiiek moet wees aangesien daar defnitiewe geur en aroma verskille
tussen koedoe- en rooibokvleis is.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/18597 |
| Date | 12 1900 |
| Creators | Mostert, Analene C. |
| Contributors | Hoffman, L.C., Stellenbosch University. Faculty of Agrisciences. Dept. of Animal Sciences. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | xi, 106 leaves : ill. |
| Rights | Stellenbosch University |
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