Thesis (MSc (Consumer Science)--Stellenbosch University, 2008. / The purpose of this study was to investigate the chemical composition mineral and cholesterol
content of the different cuts (breast, drumstick and thigh) of raw guinea fowl meat. The study
also aimed at establishing the effect of cooking method on guinea fowl quality attributes by
investigating the effect of different cooking methods on the chemical composition and sensory
attributes of the different cuts. The effect of injecting a brine solution on the chemical
composition and sensory attributes were also investigated.
There were no differences in terms of moisture content of the various cuts raw guinea fowl meat
The breast had significantly higher protein content when compared to drumstick and thigh
(P<0.05). The fat content was similar for all the cuts (P>0.05). Whilst the drumstick had
significantly the lowest value for ash content when compared to the thigh. Saturated fatty acids
(SFAs) and total unsaturated fatty acids (TUFAs) were not different (P>0.05) in all the cuts.
Drumstick had significantly higher monounsaturated fatty acids compared to other cuts (P<0.05),
and it had the highest polyunsaturated fatty acids (P<0.05). The breast had the lowest (P<0.05)
n-6 fatty acid value (44.25) and had relatively the lowest Polyunsaturated:Saturated (P:S) fatty
acid ratio of 1.74 when compared to the other cuts. High n-6:n-3 ratios, ranging from 7.05 to
16.58, were also found in all the cuts. Cholesterol was lowest (P<0.05) in the breast. Seventeen
amino acids were found, including the eight of the nine essential amino acids. Significant
differences were found in amino acid values for the different cuts. Values of iron were
significantly higher in the drumstick and thigh cuts (P<0.05), whilst drumstick had the highest
zinc content of all the cuts (P<0.05).
On investigating the effect of three cooking methods (baking-bag, foil-wrap, open-roasting at
140ºC for 65 minutes) on the chemical composition, the open-roasting method produced higher
moisture content (P<0.05) consistently for all cuts, with the breast having the highest and the
drumstick the lowest (P<0.05). The moisture content of the baking-bag method on the other
hand was consistently the lowest (P>0.05). This effect was significant for the breast, which had
lost the most moisture (P<0.05). The baking-bag method consistently resulted in a higher protein
content, which is attributed to the higher moisture loss (P<0.05) in comparison with the other
methods, resulting in a more concentrated product. With regard to the fat content no effect
resulting from the cooking methods could be observed (P>0.05), but the cuts’ natural fat content
was reflected especially in the open–roasting method (P<0.05) giving further support to the understanding that the open-roasting method indeed made the least inroads on the chemical
composition of guinea fowl meat under these restraints: controlled for cooking time and
temperature, internal temperature not controlled.
All the cuts cooked according to all the methods, had the favourable >0.4
Polyunsaturated:Saturated fatty acids (P:S) ratio, ranging from 0.91 to 1.42 between cuts and
treatments. The n-6:n-3 ratio was below the recommended beneficial value, namely <4:1, in all
the cuts irrespective of all the cooking methods, ranging from 2.47 to 3.08.
The study of the effect of the three cooking methods (baking-bag, foil-wrap and open-roast) on
the sensory attributes of the breast meat revealed that aroma-intensity of the three cooking
treatments did not differ significantly (P>0.05). Foil-wrap produced a more tender and juicier
product (P<0.05), while, when using the baking-bag method, values for flavour decreased
(P<0.05). It is proposed that a higher internal temperature (which was not controlled) was
attained when using the baking-bag method (temperature and time controlled) resulting in loss
of volatile flavour components.
The effect of the three cooking methods (baking-bag, foil-wrap and open-roast) on the proximate
composition (moisture, protein, fat and ash) of raw and cooked breast meat was investigated. As
anticipated raw breast meat had higher moisture content (74.55%, P<0.05) than the cooked
cuts, with open-roasting showing the highest (68.55%) value and foil-wrap close second
(68.12%). These values differed significantly from the baking-bag method (66.06%, P<0.05).
An investigation on the effect of brine infusion on the sensory attributes and chemical
composition (proximate and fatty acid composition, and mineral content) of breast meat, baked
in foil-wrap, was carried out using descriptive sensory analysis with the injected breast and the
control as variable. There were no significant differences (P>0.05) between the injected and the
control samples for any of the sensory attributes of aroma, tenderness, initial juiciness,
sustained juiciness and flavour. Judge:treatment variations were observed for all the attributes,
and samples differed for all attributes except for aroma. It is proposed that the use of the hand
injector could not effectively distribute the brine solution, hence the recommendation to repeat
the experiment using an electronic multineedle-injector. No effect was observed for the
proximate composition (P>0.05). Further research pertaining to cooking methods of meat of
free-range guinea fowl is recommended to address certain issues that have been highlighted.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/1898 |
| Date | 12 1900 |
| Creators | Tlhong, Tumelo Maud |
| Contributors | Hoffman, L. C., Vosloo, M. C., Moelich, E., Mellett, F., Stellenbosch University. Faculty of Science. Dept. of Consumer Science. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | Stellenbosch University |
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