Quinolizidine Alkaloids in Lupins

Quinolizidine alkaloids are secondary metabolic products that serve plants as defense and protection against herbivores. They are predominantly synthesized in lupins from the amino acid lysine. Plants store them in all parts, including their seeds. In total, about 170 known quinolizidine alkaloids exist.

Lupins, a Trending Product in Plant-based Nutrition

Thanks to their high-quality protein, essential amino acids and unsaturated fatty acids, lupins are a valuable component of vegetarian diets. They have become a popular food trend. In recent years, there hass been a growing trend in using them for both animal feed and food production. For example, as flour, in meat and milk substitutes, spreads, pasta and more.

Researchers make a distinction between wild-growing “bitter lupins” (higher alkaloid content) and cultivated “sweet lupins” (lower alkaloid content). Pre-treating the seeds through “de-bittering” can reduce the quinolizidine alkaloid content. Therefore, a bitter taste in lupin seeds or products made from them can be an indicator of quinolizidine alkaloids.

Human poisoning symptoms affect the nervous, circulatory and digestive systems. The quinolizidine alkaloids act as competitive acetylcholine inhibitors and can cause respiratory paralysis. An assumption is that doses exceeding 10 mg of quinolizidine alkaloids per kilogram of body weight may result in death.

Risk Assessment by the EFSA

The European Food Safety Authority (EFSA) has chosen the Margin of Exposure (MoE) approach for risk assessment. According to this, the lowest single effective oral dose of 0.16 mg sparteine/kg body weight was defined as the reference point for describing the risk following acute exposure to quinolizidine alkaloids. Insufficient data hinders the derivation of a health-related guideline for chronic intake. Consequently, establishing maximum levels for quinolizidine alkaloids was not possible either.

Current Warning Message on Lupin Seeds

In February, a notification ( No. 2024.0777) in the European Rapid Alert System for Food and Feed (RASFF) highlighted a lupin seed product in the German market with a total quinolizidine alkaloid content of 22 g/kg. This instance underscores the imperative of scrutinizing lupin seeds and associated products for quinolizidine alkaloid presence.

Contamination can extend beyond lupin-based products to affect other foods as well. It has been proven that quinolizidine alkaloids can be present in cow’s milk when the animals are fed with feed containing high concentrations of quinolizidine alkaloids.

Our Analytical Method for Quinolizidine Alkaloids 

Mérieux NutriSciences has validated and established highly specific LC-MS/MS determination methods for 10 quinolizidine alkaloids in numerous feed and food matrices.

We provide comprehensive analysis for a range of quinolizidine alkaloids, including spartein, lupinin, lupanin, hydroxylupanin, isolupanin, angustifolin, anagyrin, thermopsin, cytisine, and multiflorin. Our analysis covers various types of feedstuffs, such as lupin meal, lupin seeds, lupin flour, and compound feedstuffs, as well as food products containing high levels of lupin components, such as flour, cereals, and meat substitutes. Additionally, we offer analysis for quinolizidine alkaloids in moist foods with lower lupin content, including milk, dairy products, and milk substitutes.

Our Expertise in Plant-based Products Analysis

Mérieux NutriSciences offers a comprehensive suite of services, including testing, for food manufacturers specializing in plant-based products. Our expertise spans the analysis of pathogenic bacteria, allergens, plant-toxins, antinutrients, and endocrine disruptors, as well as quality aspects such as off-flavors, food fraud, and certification verification. We also cover the analysis of other alkaloids, classic contaminants, nutrient and vitamin profiles, as well as elemental and mineral composition.

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