Influence of temperature and germination time on diastatic power of blue and red maize (Zea mays L.) malts

Abstract

Maize endosperm consists of about 70 % starch, which makes it an excellent substrate for fermentation. However, due to its low diastatic power, it is used in brewing as an adjunct, mainly. In order to include both red and blue maize as an enzyme source in the brewing process, the effect of temperature and time germination on the diastatic power of malts was studied. The research consisted in a completely randomized three-factor experimental design where the involved factors were colour of maize (blue and red), germination temperature (15, 20, and 25 °C), and germination time (3, 4, 5, 6, 7, 8, and 9 days). The response variables were germination percentage, acrospire length, malting yield, and diastatic power. Data was analysed through Analysis of variance and Comparison Multiple Tukey’s Test. Results showed that both temperature and germination time encouraged the acrospire length, which had a negative effect on malting yield. Regarding to diastatic power, it maintained an increase from third to seventh germination day, at the three tested temperatures. Additionally, as the germination temperature increased, the diastatic power also increased. The highest diastatic power for blue and red maize malts were 39 and 42 °L, respectively, and it was reached when these malts were germinated for 7 days at 25 °C. It was concluded that, by germinating both blue and red maize under the resulting optimum conditions, the obtained malts would be capable of converting their own starch.

Influence of different conventional processing methods on the resistant starch content and diastatic power of Bambara groundnut (Vigna subterranean) starch

“…This increment may be due to the availability of more diastase enzymes (α-and βamylases), which are produced and secreted during the germination of the seeds compared when compared to native, boiled and dried starches since the germination process mobilized and increased enzymatic activity as previously reported (Guzmán-Ortiz et al, 2018). The Values obtained in this present study (8.25-9.34°L) were lower compared to 39 and 42°L reported for blue and red maize malts, respectively after malted for 7 days at 25 o C but similar to 9 and10°L for blue and red maize at 15 o C after malted for 3 days (Hernández-Carapiaa, et al, 2021). The temperature and time of germination also affected the DP values which did increase with an increase in temperature.…”