Potato Research

Abstract Knowledge of the parental origin of crop species is a prerequisite for formulating effective strategies for genetic conservation, management, and utilisation of genotypes in breeding programmes and genetic studies. In the case of the potato, although pedigree information is well documented, the possible lack of accurate pedigree data for certain cultivars constitutes a loss of opportunity to exploit the selection gain, the precise targeting of a market niche, or other breeding objectives. In this study, the genetic profiles of 1249 varieties were examined using a set of 35 polymorphic simple sequence repeats (SSR) markers with the available pedigree information to achieve pedigree validation. The maximum likelihood (LOD) was used to validate pedigree information of potato accessions for which the genetic data of at least one parent was available in the dataset. Our results showed that among the accessions for which both parents were genotyped, 81.7% presented a validated pedigree, while 18.3% presented a pedigree conflict (for at least one parent). Among the accessions for which only one parent was available in the dataset, 91.3% presented a validated pedigree, while 8.7% presented a pedigree conflict. Then, pedigree reconstruction was investigated to determine the most likely parent candidates for varieties whose pedigree is either questionable or lacking information.

Abstract High levels of acrylamide have been detected in French fries and potato crisps. The main pathway for acrylamide formation is from free asparagine and reducing sugars in the Maillard reaction. Asparagine provides the backbone of the acrylamide molecule. The rate of acrylamide formation increases significantly when asparagine is heated with carbonyl compounds such as reducing sugars. According to current knowledge, thermal load applied during processing in terms of temperature and duration has a significant influence on acrylamide formation in potato products depending on the concentrations of total reducing sugars and free asparagine in potato tubers. Glucose and fructose contents are generally regarded as a good indicator of the acrylamide forming potential of potato tubers. The latest regulation from the European Commission requires that food business operators take mitigation measures to lower the acrylamide content of their products below benchmark values. Therefore, efforts should be directed to reduce the amount of acrylamide formed in potato products. Excessive accumulation of acrylamide in potato products can be prevented during processing if the exposure of the product surface to high temperatures is limited. This is possible with temperature-programmed frying, which targets outer crust layers and cooked interiors for French fries. The same effect can be obtained by blanching potato strips in the microwave for a few seconds before deep frying. Combined technologies, such as partial baking followed by radio frequency post-drying, can also be used to control acrylamide formation during processing.

Abstract Potato (Solanum tuberosum L.) is an important commercialised food crop in Kenya. Recently, Kenya has realised a huge increase in the number of formally released potato varieties. The performance of these varieties is not clear and their adoption across various growing environments is low. This study explored how availability, access, quality and systems of seed and storability and market demand of potatoes influence farmers’ decisions on choice of varieties they grow and how they select seed for planting in the different seasons. Focus group discussions (83 farmers) and a household survey (225 farmers) were conducted in three major potato growing areas (Lelan, Saboti and Kaptama) in north-western Kenya. Results showed that farmers mainly used farm-saved seed and only 4.9% had used certified seed, while 71% indicated that certified seed was not available locally. Almost all farmers ensured they used healthy seed by visually examining the seed tubers while most farmers also examined the health of the crop in the field before harvest. Farmers renewed their seed depending on the number of cycles used, infection, decline in yield and availability of clean seed. Seed was usually renewed for up to after 5 years of recycling, and generally involved the varieties Shangi, Kabale and Arka. Farmers ranked five variety traits: tuber yield, disease resistance, market demand, early maturity and storability as most important in the choice of a variety. Farmers understood the importance of dormancy and had methods for managing dormancy, but their knowledge was biased to the few varieties they had, particularly Shangi, the predominant variety in the market. Despite agronomic attributes, market demand featured as a primary determinant of variety choice amongst farmers. The findings from this paper can guide use of seed, adoption of new varieties and future breeding of potato varieties for Kenya.

Abstract In supermarkets in the Netherlands, well over 150 potato products are displayed. They can be distinguished by heating characteristics (boiled or fried), appearance (e.g., intact tuber pieces or formed hash browns), dehydrated (e.g., snacks and flour) and storage temperature (e.g., ambient and frozen). Fancier products (frozen formed versus chilled blanched) require more processes and operations in factories and are more expensive; consumers appreciate them because they offer more convenience. Heatmapping and hierarchical clustering were carried out twice within the domain of classes of products and their attributes. In a theoretical triangulation, consumers give high scores to low prices and a wide range of products, tastes and sizes where processors give these attributes a low score. Processes in factories include dehydration, heating, cooling and transformation. Examples of the latter are modification of starch to increase the range of applications in the food industry, forming of mash and shreds to produce croquettes and hash browns and expansion to make snacks. Processes require operations such as washing, cutting, blanching and packing. In total, between the arrival of the tubers at the gate and leaving as packed products to outlets, 66 operations are distinguished. French fries undergo some 30 operations and to produce flakes, 8 suffice. Heatmapping and hierarchical clustering differentiate a group of physical operations (with attributes associated with heating and cooling that require much energy) and mechanical ones (related to separation, grading, sorting for instance and size reduction of which shredding is an example that require little energy). The wide range of operations in large factories, reducing the moisture content and longtime storage at low temperatures, distinguishes potato from wheat that has fewer operations while increasing the moisture content in relatively small bakeries and the product, bread, stored for about one day in ambient conditions.