| dc.description.abstract | The presence of acrylamide in several carbohydrates rich foods baked at high temperatures and
its classification as a suspected human carcinogen calls for a concerted effort to minimize its
presence in human diet. It is mainly formed in fried and baked carbohydrate rich foodstuffs such
as potato chips and crisps through maillard reaction at elevated temperatures.
This study was designed in three phases with each phase covering a specific objective. The first
part of the study involved a cross-sectional survey of commercial potato crisp outlets in Nairobi
and laboratory analysis of the samples purchased. Both purposive and simple random sampling
was used in choosing the districts to be surveyed. A total of 35 brands in duplicates were
purchased from retail outlets in Nairobi and 15 unbranded samples from the street vendors within
the five districts. The parameters analysed were moisture content, colour and acrylamide
content. The second objective involved assessing the exposure to acrylamide through
consumption of potato crisps in Nairobi, Kenya. Potato crisps consumption survey was carried
out among crisps consumers. The data were collected from the consumers at the retail outlets
where they bought the crisps. Consumption data were combined with contamination data arising
from analysis of crisps from retail outlets and street processors in the same region and dietary
acrylamide exposure was calculated using probabilistic approach. The third objective involved
the determination of the effect of variety and processing conditions on crisps from local potato
varieties. Four potato varieties; Tigoni, Kenya Mpya, Dutch Robjin and Sheherekea were planted
under standard conditions in KARI, Tigoni. Harvesting was done at maturity and the tubers were
sliced to three thicknesses of 1.0mm, 1.5mm and 2.0mm which were then each subjected to
frying temperatures of 160°C, 170°C and 180°C. The raw tubers were analyzed for dry matter
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content and reducing sugars while the processed potato crisps were analyzed for colour,
moisture, acrylamide and sensory properties.
Acrylamide levels significantly (P≤0.05) differed between the traded crisps brands ranging from
non-detectable levels to 8666 μg kg−1 in the branded samples while in the unbranded samples it
ranged from 5666 μg kg−1 in Vendor 7 to 9499 μg kg−1 in Vendor 6. There was a significant
difference (P≤0.05) in acrylamide levels between the branded and the unbranded (street) potato
crisps. The levels of acrylamide in the branded flavoured potato crisps ranged from nondetectable
levels to 5151 μg kg−1
The mean acrylamide intake was 1.57μg/kg bw/day while the 95th (P95) percentile was 5.1μg/kg
bw/day with Margins of Exposures (MOE) being respectively 197 and 61. The acrylamide intake
was significantly (P≤0.05) higher in street processed crisps (non-branded) with a mean value of
2.26 μg/kg bw/day and 95th percentile of 6.54 μg/kg bw/day, and MOE being respectively 137
and 47. The extremely lower MOEs exposure to acrylamide by the consumers could mainly be
attributed to higher contamination levels.
Acrylamide levels significantly (P≤0.05) differed between the varieties and ranged from 13480
μg kg−1 in Kenya Mpya to Dutch Robjin recording the lowest levels of the acrylamide 3150 μg
kg−1. Acrylamide levels significantly increased with frying temperature and slice thickness.
Important steps are therefore required to mitigate the high exposure by reducing level of
acrylamide contamination and decreasing consumption. Appropriate varieties and processing
parameters have to be chosen to ensure less acrylamide in potato crisps.
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