engleski

Development of enzymatic activity in wheat grain during germination process

This paper investigated development of enzymatic power in wheat grain during germination process (expressed as α-amylase activity and total diastatic power). The aim was to determine the optimal germination time in order to achieve the best results for investigated indicators in relation to the recommended values. Wheat samples underwent germination process in controlled conditions, regarding temperature and air humidity, over a period of 7 days. Obtained results for total distatic power were in range from 240° WK in starting sample to 420° WK at the end of the germination process. Results for α- amylase activity were in range from 0 DU/dm in starting sample to 60 DU/dm at the end of germination process. It was determined that germination time ranging from 158 to 168 h (from 5.5th – 6th day of germination) is optimal to obtain recommended values for wheat malt (diastatic power 250 – 420 °WK, α-amylase activity 40 - 60 DU/dm). Satisfying results were achieved on the half of the 4th day of germination (diastatic power ≈ 300 °WK, α-amylase activity ≈ 28 DU/dm). Furthermore, it was determined that by extending the germination time beyond 168 h no significant up growth of any of investigated indicators occurred, though other investigated indicators of malt quality were distorted. In conclusion, obtained results indicate that optimal germination time for synthesis of enzymes that affect the total diastatic power of malt (except β-amylase which is activated only during the germination process) and α- amylase synthesis, is between 156 - 168 h. In case of compromising these indicator values with the rest of important malt quality indicators, the optimal germination time ranges from 120 - 140 h.

wheat, germination, alpha-amylase activity, diastatic power, malting, optimization

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