Boerewors is a South-African fresh sausage, made from beef and pork and
flavoured with salt, pepper and various spices, especially coriander. It may
contain a maximum of 450 mg/kg SO2 as preservative. Until recently, the use
of SO2 has had GRAS (Generally Regarded as Safe) status. Investigations
have indicated certain asthmatic individuals were placed at risk by relatively
small amounts of sulphites. The increased demand for minimally processed,
extended shelf-life foods have renewed interest in exploitation of natural
antimicrobials for food preservation uses.
The aim of this study was to evaluate the efficacy of Citrox as a natural
preservative in Boerewors. Citrox comprises of a range of phyto-alexins
derived from the pith and rind of green Bergamont oranges and fruit acids.
Seven Boerewors models were made following a typical commercial
procedure: the control containing no preservative, current dosage of SO2 in
Boerewors (450 mg/kg), two dosages of Citrox on its own at 1% and 2%
addition, a reduced amount of SO2 (100 mg/kg) on its own and Citrox in
combination with reduced amounts of SO2 (1% Citrox + 100 mg/kg SO2 and
2% Citrox + 100 mg/kg SO2). The models were stored at 4 ºC for 6 days
under retail display conditions. The models were evaluated every 48 hours for
microbiological growth as expressed by total aerobic plate count (TAPC),
coliform count, Staph. aureus count, yeast and mould count. The models were
also evaluated every 48 hours for colour changes as expressed by the colour
a* value (redness), colour b* value (yellowness) and colour L* value
(lightness). The models were evaluated after 6 days, and again after 100 days
storage at -18 ºC, for lipid oxidation as expressed by TBARS (thiobarbituric
acid reactive substance). The models were also evaluated organoleptically by
a sensory panel. It was established that all the treatments had significantly lower counts than
the control over the 6 day storage period on TAPC. There was no significant
difference in the counts of 450 mg/kg SO2, 2% Citrox, 100 mg/kg SO2 + 1%
Citrox and 100 mg/kg SO2 + 2% Citrox. The 450 mg/kg SO2 and 100 mg/kg
SO2 + 2% Citrox had significantly lower coliform counts than the control.
Against yeasts and moulds, 100 mg/kg SO2 + 2% Citrox had significantly
lower counts than the control and 450 mg/kg SO2.
Citrox had a negative effect, on its own and in combination with 100 mg/kg
SO2 on the colour of the Boerewors. The colour a* values were significantly
lower than those for the control and 450 mg/kg SO2. There was very little
effect on the colour L* value, most values stayed relatively stable over the 6
days, the 2% Citrox and 100 mg/kg SO2 + 2% Citrox showed the highest
values. For all the models, there were a slight decrease in the colour b* value.
At the end of the 6 days, all models had similar values.
Over the 6-day fresh display period there was no significant difference in the
TBARS values for all the models. After 100 days storage at -18 ºC, 450 mg/kg
SO2 had significantly lower values than the control and the rest of the models.
The control had the same values as the rest of the models, which led to the
conclusion that although the Citrox had no anti-oxidant capabilities, it also did
not increase lipid oxidation.
The sensory panel found that the models containing 2% Citrox had a slight
sour flavour (can be explained by the fruit acids in Citrox in combination with
the vinegar added to the Boerewors formulation), however the average scores
for these models were still found to be âliked slightlyâ to âliked moderatelyâ.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-10182011-124045 |
| Date | 18 October 2011 |
| Creators | Van Schalkwyk, Charles Petrus Benjamin |
| Contributors | Prof CJ Hugo, Prof A Hugo |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-10182011-124045/restricted/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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