Effects of Aerobic and Anaerobic Germination on the Debranching Enzyme, Limit Dextrinase, in Barley Malt

McCafferty, Calum A.; Perch-Nielsen, Niklaus; Bryce, James H.

doi:10.1094/asbcj-58-0047

Cited by 7 publications

(6 citation statements)

References 4 publications

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“…Despite the pioneering studies on barley which date back to over a century, for example, in the 1900s 53 , in the 1920s 19 , in the 1950s 29,51 , in the 1960s 33 and studies by scientists of the 1970s to the present day 4,6,[12][13][14]18,[20][21][22][23]27,28,[30][31][32][35][36][37][38]40,41,44 , the complexity and incompleteness of our knowledge of grain physiology have resulted in continuous research on cereals, with research studies on barley and malt receiving the most attention when compared to other cereals. This is because of the pivotal role malted barley plays in many applications in the food, alcoholic and non-alcoholic beverage, baked products and the spirit industries.…”

Section: Effect Of Different Steeping Conditions On Endosperm Modificmentioning

confidence: 99%

“…The friabilitimeter was introduced in the early 1980s as a mechanical test to assess the uniformity of endosperm modification of malt samples 24 , although friability scores do not always correlate to brewhouse performance 1,26,27,45,47 . The extensive research into barley has led to a better and in-depth understanding of the physiology of barley and malt 4,6,[12][13][14]18,[20][21][22][23]25,[27][28][29][30]31,32,[35][36][37][38]40,41,44 . As a result, experimental observations and conclusions have been drawn and accepted as a pattern of behaviour for barley and malt.…”

Section: Effect Of Different Steeping Conditions On Endosperm Modificmentioning

confidence: 99%

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Effect of Different Steeping Conditions on Endosperm Modification and Quality of Distilling Malt

Bryce

Goodfellow

Agu

et al. 2010

Journal of the Institute of Brewing

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J. Inst. Brew. 116(2), 125-133, 2010This study showed that when barley was steeped in water for either 8 h or 16 h, hydration of endosperm materials was suboptimal and modification of endosperm materials of barley malt was inadequate. The malt produced under these steeping regimes gave poor friability scores and produced a large number of whole grains. When barley was steeped for 24 h on a continuous basis, or when a regimented standard steeping method was used, the malt produced gave higher friability scores and a much lower number of whole grains. An important relationship was found between friability scores and whole grain results for the malt samples produced under these conditions. Optic barley, whose endosperm was more difficult to hydrate, gave a strong negative correlation between friability scores and number of whole grains at R 2 = 0.8689. Oxbridge, whose endosperm was more easily hydrated, gave a much stronger negative correlation between friability scores and number of whole grains at R 2 = 0.9769. Rapid visco-analysis (RVA) results also confirmed that steeping the barley samples for only 8 h or 16 h produced malt that modified poorly as the RVA peak viscosities were very high. RVA pasting results further confirmed that when barley was steeped for 24 h on a continuous basis, or when a standard regimented steeping method was used, good quality malt was produced and no differences were found in the RVA peak viscosities of the barley malt samples produced under the two different steeping conditions. The results of protein breakdown (proteolysis) during these experiments, measured in terms of total soluble nitrogen (TSN) production, or soluble nitrogen ratio (SNR) further confirmed that optimal proteolysis was achieved when barley was steeped for either 24 h on a continuous basis, or with a standard steep. Optimal results were also found for hot water extractable materials such as hot water extract (HWE) and free amino nitrogen (FAN) when barley was steeped for 24 h or the standard steep. The 24 h continuous steep for barley produced quality malt comparable to that obtained when the standard regimented steep was used for steeping barley. For both Optic and Oxbridge barley, with a 24 h continuous steep, produced malt that gave significantly higher fermentabilities and PSY values, regardless of germination time, than those obtained using a standard regimented steep. Therefore steeping barley for 24 h on a continuous basis prior to malting will produce good quality malt for some barley samples/varieties. This will help to reduce water usage during steeping, will save steeping time thereby reducing malting time and will reduce the amount of water for effluent treatment. All of these factors result in an overall cost saving for the malting industry.

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Section: Effect Of Different Steeping Conditions On Endosperm Modificmentioning

confidence: 99%

Section: Effect Of Different Steeping Conditions On Endosperm Modificmentioning

confidence: 99%

Effect of Different Steeping Conditions on Endosperm Modification and Quality of Distilling Malt

Bryce

Goodfellow

Agu

et al. 2010

Journal of the Institute of Brewing

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“…Normal aerobic germination was carried out using a Seeger micromalting plant 4,25 . Anaerobic germination was based on Dixon's enzymic malt (patent 582,423, November 1946) and achieved by tightly packing partially malted grains into 60 mL plastic containers, which were then sealed and incubated at 37°C.…”

Section: Malt Productionmentioning

confidence: 99%

“…Anaerobically produced malt is known to have a high 'free' activity equivalent to activities found following extraction of 5 d aerobic malt with DTT 25 . Limit dextrinase activities of the anaerobically produced malt extracted in the presence of DTT indicated that the almost all of limit dextrinase was present in the free form (results not shown).…”

Section: The Effect Of Prolonged Extraction Of Limit Dextrinase From mentioning

confidence: 99%

“…Malt often has a free enzyme activity making up less than 20% of the potential total activity 14 , although activation of free enzyme approaching 35% has been found in barley malts of variety Static and Chariot 31 . In malt, free limit dextrinase activity was increased above these levels by germinating grains under anaerobic (reducing) conditions, an environment which could have increased the activity of cysteine proteases 3,25 , which may have degraded the limit dextrinase inhibitor. Anaerobically germinated grain, following a period of normal malting, produced grains containing a free limit dextrinase activity constituting over 80% of the total limit dextrinase activity.…”

Section: Introductionmentioning

confidence: 99%

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Limit Dextrinase - Does Its Malt Activity Relate to Its Activity During Brewing?

McCafferty

Jenkinson

Brosnan

et al. 2004

Journal of the Institute of Brewing

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Limit dextrinase (EC 3.2.1.142) hydrolyses α‐1,6 glucosidic bonds in amylopectin and branched dextrins. Measurement of limit dextrinase activity during fermentation of unboiled wort at the pH of the wort has shown that its activity increases almost 10 fold during the first 10–15 h of fermentation and this increase in activity is unaffected by the presence of leupeptin, a cysteine protease inhibitor. The increase in activity seen when assays were carried out at pH 5.5 was much smaller and was reduced by leupeptin. The activity of limit dextrinase declined slowly during the latter part of the fermentation. It was established that the optimum pH for rapid extraction and assay of malt limit dextrinase in the absence of a reducing agent is approximately 4.5, but in the presence of dithiothreitol, at pH 5.5, activities 2–3 times higher can be obtained after 5 h extraction (600–700 mU/g dry weight). Limit dextrinase activities after 1 h extraction at mashing temperatures were below 20 mU/g dry weight if the mash pH was below 5.0. It is concluded that at pHs below 5.0, where limit dextrinase activity is below its optimum for activity, limit dextrinase activity increases due to dissociation of the inhibitor/enzyme complex. The protection from mashing temperatures of 65°C afforded by the inhibitor is lost at these lower pHs.

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2012

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Effects of Aerobic and Anaerobic Germination on the Debranching Enzyme, Limit Dextrinase, in Barley Malt

Cited by 7 publications

References 4 publications

Effect of Different Steeping Conditions on Endosperm Modification and Quality of Distilling Malt

Effect of Different Steeping Conditions on Endosperm Modification and Quality of Distilling Malt

Limit Dextrinase - Does Its Malt Activity Relate to Its Activity During Brewing?

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