Determination of folate content in Swedish brown beans (Phaseolus vulgaris L.) from Öland : the impact of cultivar, year of production and region of origin

Sammanfattning: The term folate refers to all naturally occurring derivates of pteroic acid that are biologically active, except folic acid. Over 150 vitamers are possible, but only around 50 are found in foods. Pulses are beneficial from an environmental aspect due to their nitrogen fixation availability, but also from a nutritional point of view, since they are protein rich and contain high amounts of essential micronutrients such as folate. Swedish brown beans (Phaseolus vulgaris) are mainly grown on the island of Öland, but test cultivations have recently been performed successfully on the island of Gotland and in parts of Skåne. The beans demand high (>6.5) pH due to the symbiosis with the rhizobia bacteria, high humidity during germination and flowering and dry conditions during harvest and drying. In this study the folate content was determined by a microbiological assay in the cultivars Karin and Kat-ja, to examine if the content differed between cultivars, years and regions. If such a relation would exist, the aim was to explain the differences by meteorological con-ditions. Furthermore, the aim was to determine the water content of the beans, to examine if it would be related to the factors cultivar, year or region. The content of folate was determined to be 157±26 µg/100 g in Swedish brown beans from Öland. The factors cultivar and region did not have an impact on the folate content in the beans. The folate content differed between years, plausibly explained by different meteorological conditions between the years. The beans from 2009 contained the highest contents of folate, when the meteorological conditions were optimal. The water content in Katja differed between years, with the highest amounts in the beans from 2009, indicating that water binding substances such as proteins and carbohydrates were present to a higher degree. The water content differed between Katja and Karin, indicating the presence of different amounts of water binding substances in the cultivars.