Effects of malting on β‐glucanase and phytase activity in barley grain

Abstract

The effects of malting on b-glucan and phytate were investigated in one naked and one covered barley by a full factorial experiment with three factors (steeping temperature, moisture content and germination temperature) each with two levels. Analysis of total content of b-glucan in the malted samples showed small changes after steeping at the high temperature (48°C), while steeping at the lower temperature (15°C) gave a signi®cantly lower content. This trend was even stronger for b-glucan unextractable at 38°C. Analysis of the activity of b-glucanase for the samples steeped at 15°C showed a strong increase over the time of germination, while those steeped at 48°C had a much slower development. The other two factors in¯uenced the outcome to a small extent, mainly because the steeping temperature was the most important factor overall where any changes in b-glucan and b-glucanase were observed. When b-glucan was extracted at 100°C, a larger yield was obtained, and this was in¯uenced by the steeping temperature in a much stronger way than for b-glucan extracted at 38°C. Determination of average molecular weight for b-glucan extracted at 100°C gave a lower value for samples steeped at 15 than at 48°C. The design did not have any large effects on phytate degradation and phytase activity. However, it indicated that selective control of the enzymes might be possible, since phytase activity was barely affected by the parameters studied, while b-glucanase was heavily affected.

Effects of variety and steeping conditions on some barley components associated with colonic health

“…This resulted in a limited degradation of total AX, β‐glucan MW and also phytate, since the activity of endo‐xylanase, β‐glucan solubilase (increases β‐glucan availability for degradation) and phytase are higher after 3 days of germination. This can explain the small changes in the β‐glucan MW and MW distributions (data not shown), which was also reported in other studies . To properly understand the effect of the steeping conditions in the whole range of β‐glucan MW, a method with a lower MW limit of detection is required.…”

“…The combination of high steeping temperature and addition of lactic acid to the steeping water was found to contribute to a low β‐glucanase activity and a preserved content of β‐glucan. The malting was performed based on a method previously described by us …”

Factors Influencing β‐Glucan Levels and Molecular Weight in Cereal‐Based Products

“…Malting involves soaking (steeping), germination, and drying of the whole kernel. Rimsten et al (2002) observed steeping of grains at lower temperature (15°C) and increased β-glucanase activity had an impact on β-glucan content. This gives rise to a filtration problem in the brewery and it may precipitate in maturing of beer, causing chill haze (Bamforth and Barclay 1993).…”

The effect of germination and metallic salts on the stability of enzymes of three high yielding varieties of maize (Zea mays L.) in respect of Bangladesh

“…The higher protease activity was found at 48 hours in BHM-3, BHM- Koshiba and Minamikawa (1983). In cereal seeds, germination increase oligosaccharides and amino acids concentration as observed in barley (Rimsten et al, 2003), wheat (Yang et al, 2001) and rice (Manna et al, 1995). It was established that a number of dry matters reduced in germinated wheat and the content of mineral substances, protein and activity of fermented α-and β-amylases, cellulases, proteases, and maltase were greater than in non-germinated wheat, observed by Kraujutiene et al (2010).…”