Lyophilised legume sprouts as a functional ingredient for diamine oxidase enzyme supplementation in histamine intolerance

Abstract

Diamine oxidase (DAO) is one of the key enzymes involved in the degradation of dietary histamine. An imbalance of histamine scavenging systems leads to histamine intolerance, a diet-related disorder that may be tackled by following a low-histamine diet. Recently, the supplementation with exogenous DAO enzyme of animal origin has received the green light as a novel food to enhance intestinal degradation of histamine. This work performed a screening for histamine-degrading capacity of Leguminosae species in order to explore its potential suitability as plant-derived active ingredient of enzymatic supplements. In vitro DAO activity was determined both in raw pulses and lyophilised sprouts by an enzymatic assay coupled to UHPLC-FLD and several germination and storage conditions were assessed. The sprouts of edible legumes showed an in vitro histamine-degrading capacity ranging from 36.0 to 408.3 mU g−1, much higher than that found for the non-germinated seeds (0.14–1.95 mU g−1). The germination of legume seeds for 6 days in darkness provided the maximum DAO activity. Only the freezing storage of the lyophilised sprouts kept the enzymatic activity intact for at least 12 months. These results demonstrate that certain edible legumes could be suitable for the formulation of DAO supplements for the treatment of histamine intolerance.