Effect of Dilute Alkaline Steeping on Mold Contamination, Toxicity, and Quality Parameters of Buckwheat Malt

Abstract

Steeping in dilute sodium hydroxide (NaOH) was investigated with the primary aim of reducing molds and preventing toxicity of buckwheat malt. Samples of common buckwheat (Fagopyrum esculentum) obtained from Montenegrin farmers in the mountain area of northern Montenegro were steeped in 0.1, 0.2, and 0.3% NaOH. The effects of these solutions on mold contamination, ochratoxin A (OTA), out-of-steep moisture content (SMC), rootlet length, total nitrogen, total soluble nitrogen (TSN), free amino nitrogen (FAN), diastatic power (DP), and color of buckwheat malt were evaluated. Steeping in 0.1, 0.2, and 0.3% NaOH reduced the levels of molds from 105 to 103 CFU/g and steeping in 0.2% NaOH destroyed some of the mold genera. Steeping in 0.1, 0.2, and 0.3% NaOH reduced the level of OTA, especially in 0.2% NaOH, where the level of OTA after the malting process was below food safety regulations (5 μg/kg), and in 0.3% NaOH, where the level was below the limit of detection (0.1 μg/kg). Steeping in 0.1, 0.2, and 0.3% NaOH significantly (P < 0.05) increased levels of SMC, TSN, FAN, DP, wort color, and pH. However, it significantly reduced (P < 0.05) the level of extract and length of rootlets. The level of OTA contamination in stored buckwheat malt, which contained Penicillium genera, significantly increased (P < 0.05) over a period of 60 and 90 days. Steeping in 0.2% NaOH is proposed as a method for the reduction of mold and OTA contamination during buckwheat malting as well as prevention from further OTA production during storage.