Possibilities of reducing amounts of vicine and convicine in faba bean suspensions and sourdoughs

Marjo Pulkkinen,Jutta Varis,Kati Katina,Rossana Coda,Anna-Maija Lampi,Vieno Piironen

doi:10.1007/s00217-019-03282-4

Marjo Pulkkinen, Jutta Varis + Show 4 more

Open Access

https://doi.org/10.1007/s00217-019-03282-4

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Abstract

Vicine and convicine may be removed from faba bean by hydrolysis to the corresponding aglycones, divicine and isouramil. For total elimination of their toxicity, further degradation of the aglycones should be shown. The aim of the study was to investigate hydrolysis of vicine and convicine using the enzymatic activity in faba bean in flour suspensions and selected lactic acid bacteria used as starters for faba bean fermentation. In addition, the effect of acidity on the stability of vicine and convicine was investigated. Sourdoughs were used in a baking process to obtain breads as final products. Vicine, convicine, and their aglycones were analyzed using reversed phase high pressure liquid chromatography with UV detection (RP-HPLC-UV). Incubation of the suspensions showed rather small vicine and convicine losses. Acidity itself did not cause losses under the conditions studied, apart from that of convicine at low pH. In sourdough fermentation with strains of Lactobacillus plantarum and Pediococcus pentosaceus, losses of vicine and convicine were dependent on the fermentation temperature and the β-glucosidase activity of the starter. Compared to fermentation at 20 °C, more intense acidification at 25 °C resulted in decrease of vicine up to 85% and convicine up to 47%. Levels of vicine and convicine in breads were comparable to levels in sourdoughs. Furthermore, the aglycones were not detected from breads.

Highlights

Grain legumes have been minor crops among the high-yield cereals and oilseeds that have notable fertilizer requirements
The losses of vicine and convicine were rather low during the short incubations of faba bean flours, indicating low activity of the endogenous β-glucosidase for these substrates (Fig. 1a)
87–94% of vicine and 89–95% of convicine was left in the suspensions of Kontu flour after incubation for 4 h at the pH values and temperatures tested

Summary

Introduction

Grain legumes have been minor crops among the high-yield cereals and oilseeds that have notable fertilizer requirements. Alternatives for imported soybean are needed, and grain legumes, including pea, faba bean, lupine and lentil could be grown locally in Europe [1]. Faba bean has a high protein yield and an acceptable yield stability compared to other protein-rich crops [1]. There is growing interest in plantbased proteins in human nutrition [2]. Addition of faba bean flour to cereals can increase their protein content and supplement nutritional quality by, for example, complementing the amino acid profile. Faba bean contains certain harmful compounds that have not been reduced notably via plant breeding [3, 4]

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