The Impact of Kilning on Enzymatic Activity of Buckwheat Malt
Blaise Patricia Nic Phiarais1,2, Hilde Henny Wijngaard1,2 and Elke Karin Arendt1,3
1 Department of Food and Nutritional Sciences, National University of Ireland, University College Cork, College Road, Cork, Ireland.
2 Bio Transfer Unit, National University of Ireland, University College Cork, College Road, Cork, Ireland.
3 Corresponding author. E-mail: e.arendt@ucc.ie
J. Inst. Brew. 111(3), 290-298, 2005 | VIEW ARTICLE
ABSTRACT
This study investigated the impact of kilning on β-amylase, β- amylase (total and soluble), β-glucanase and protease activities in buckwheat malt. Common buckwheat (Fagopyrum esculentum) was steeped at 10°C for 12 h, germinated at 15°C for 4 days and kilned at 40°C for 48 h. Moisture content and enzymatic activities were determined throughout the kilning period. Results showed moisture content was reduced from 44% to 5% after 48 h of kilning at 40°C. β-Amylase was found to exist in a soluble and latent form in buckwheat. Maximum activity of (a) β-amylase, (b) total β-amylase, (c) soluble β-amylase, (d) β- glucanase and (e) protease activity occurred after (a) 8, (b) 7, (c) 30, (d) 0, and (e) 8 h of kilning, respectively. The final malt exhibited very little β-glucanase and cellulase activity. Proteolytic activity was low in buckwheat malt when compared to the barley malt control. All enzymatic activities were found to decrease during the kilning stage. Results indicated that after prolonged kilning at 40°C, inactivation of hydrolytic enzymes occurred; two-stage kilning for shorter periods is recommended. Although, amylolytic activity was low in malted buckwheat, buckwheat malt shows potential as an ingredient for the brewing and cereal industry.
Key words:
Buckwheat, enzyme activity, free amino nitrogen (FAN), kilning, malting, total nitrogen (TN), total soluble nitrogen (TSN).
Publication no. G-2005-1108-310 ©2005 The Institute & Guild of Brewing