Acrylamide Contamination In Commercial Potato Crisps In Kenya: Levels Of Intake And Effects Of Processing Parameters In Local Cultivars

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 xii | P a g e 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. .