Institut für ökologische Chemie, Pflanzenanalytik und Vorratsschutz
Potatoes are staple foods and important sources of industrial raw materials such as starch. Depending on the intended use, the most important properties of potatoes for society, consumers, industry and breeders, are high nutrient or starch contents, suitability for processing, edibility and yield, as well as agronomic characteristics,.In 2020, 360 billion tons of potatoes were produced worldwide; Germany was the second largest potato producer in the EU with 11.7 billion tons (faostat.com). In addition to the consumption of fresh potato tubers, their processed products (starch, potato chips, chips, flakes, granules) are an important basis for human nutrition and industrial applications (paper, textiles, construction additives, ceramic materials, bioplastics, flocculants and many more). However, the high-quality protein fraction that is produced during industrial starch production cannot be efficiently utilized to date, as glycoalkaloids (GAs), which are harmful to health, accumulate in the protein fraction. In its statement no. 010/2018, the German Federal Institute for Risk Assessment (BfR) classified a daily intake of 0.5 mg TGA/kg body weight and a content of less than 100 mg TGA/kg fresh potato weight as safe (NOAEL: NO observed adverse effect level). The CONTAM panel in the EFSA study set a limit of 1mg TGA/kg body weight/day as the LOAEL (LOWEST observed adverse effect level). For this reason, the amount of GAs enriched in the protein fraction from potatoes is a critical factor in its utilization. Removing the GAs from the protein fraction is an expensive and energy-intensive process.Reducing the GAs in the potato would make it possible to utilize the protein fraction from starch production or potato waste and thus expand the value chain of the processing industry enormously. For the consumer, potatoes and potato products would become nutritionally more valuable and waste-free, as parts containing GAs, especially the peel, could now also be consumed. It is assumed that 90% of potatoes are consumed as peeled food (EFSA), whereby potentially health-promoting substances in the peel are lost. A reduction in GAs could lead to the inclusion of peels with their fiber, secondary metabolites such as polyamines and polymers in many potato products.Plant secondary metabolites are small molecules that are synthesized by the plant either constitutively or in response to biotic or abiotic stress factors. They play an important role in adapting to changing environmental conditions (temperature, drought, waterlogging) and in resistance and defense mechanisms. GAs are important factors in the defense against plant pests and pathogens. A reduction of these substances could result in an increased susceptibility of the potato to diseases and pests, with negative consequences for harvest quality and quantity if appropriate plant protection measures are not taken. In the interests of an environmentally friendly and resource-conserving bioeconomic approach, synthetic plant protection products (PPPs) should be avoided. An economically and ecologically sensible alternative is the breeding of other plant defense substances to protect the plant and ensure yield and quality.Potato tubers from the current market range contain hundreds of secondary metabolites with are major differences between potato varieties. Only a few of the metabolites have been identified and characterized for their biological functionality. In 2022, our groupo from JKI-ÖPV to identify new compounds in potato tubers. Bioassays with a very common compound showed clear negative effects on insect pests, pathogenic fungi and oomycetes (Gorzolka et al., in preparation). The substance content in the tuber peel varies greatly depending on the variety and is 0 - 0.5 % of the dry weight. They are therefore present in considerable quantities and could have plant protective effects. These and other metabolites in the tuber could compensate for the feared reduction in resistance and resilience of the potato in the event of a reduction in GAs and thus ensure yield and quality despite low GA contents.The aim of the project isA) Reduction of the alkaloid content in potato tubers to expand the value chainB) To increase the resistance of potato plants through the discovery of new bioactive ingredients and the breeding combination of various new and known resistance mechanisms against various potato pathogens.C) Creation of a permanently storable ÖkoTILLING population
Federal Ministry of Food and Agriculture
