Proteolysis of Sorghum Endosperm Proteins when Mashing with Raw Grain Plus Exogenous Protease and Potassium Metabisulphite

Ng'andwe, Chisala C.; Hall, A. N.; Taylor, John R.N.

doi:10.1002/j.2050-0416.2008.tb00778.x

Cited by 18 publications

(17 citation statements)

References 26 publications

(36 reference statements)

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“…The sorghum phytate content fell within the range previously reported of 300–2000 mg per 100 g whole grain flour . The phytate content of the maize was higher than the average reported 610–988 mg per 100 g whole grain flour , but maize with a phytate content of 1443 mg per 100 g whole grain flour has been reported .…”

Section: Resultssupporting

confidence: 72%

Potential for improvement in yeast nutrition in raw whole grain sorghum and maize lager brewing and bioethanol production through grain genetic modification and phytase treatment

2012

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Brewing and bioethanol production with raw grain and exogenous enzymes produces wort with satisfactory hot water extract (HWE). However, the free amino nitrogen (FAN) and mineral content can be too low, owing to low protein digestibility (PD) and phytate-mineral chelation, respectively. This study evaluated the potential for improvement in yeast nutrition in raw whole sorghum and maize brewing and bioethanol production by genetic modification (GM) of sorghum to improve PD and reduce phytate content, and by treatment with exogenous phytase. While phytase addition decreased sorghum spent grain phytate content (88%) and content of minerals (17 to 59%; i.e. increased wort mineral content), it did not affect maize phytate spent grain mineral content or HWE significantly. However, phytase addition did increase maize wort FAN (20%), sorghum HWE (2.8 percentage points) and wort FAN (23%). GM sorghum gave reduced spent grain mineral contents (11-38%), increased HWE (5.5 percentage points) and wort FAN (71%). Hence, genetic modification of sorghum to improve PD and reduce phytate content has considerable potential in raw grain brewing and bioethanol production to improve yeast nutrition.

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Section: Resultssupporting

confidence: 72%

Potential for improvement in yeast nutrition in raw whole grain sorghum and maize lager brewing and bioethanol production through grain genetic modification and phytase treatment

2012

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“…Poor protein hydrolysis is related to the intrinsic structure of the sorghum kafirin storage protein . An earlier study in our laboratory showed that kafirin cross‐linking by disulphide bonding was a major factor contributing to poor sorghum protein digestibility .…”

Section: Resultsmentioning

confidence: 92%

Influence of sorghum grain type on wort physico-chemical and sensory quality in a whole-grain and commercial enzyme mashing process

et al. 2013

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Short title: Sorghum grain type and wort physico-chemical and sensory quality ABSTRACTTo determine the most suitable types of sorghum for whole grain adjunct in lager beer brewing, 14 cultivars of five different types: white tan-plant, white not tan-plant, red non-tannin, white tannin (Type II), and red tannin (Type III) were evaluated. The effects of grain type on wort physico-chemical and sensory quality with raw grain and malt plus commercial enzyme mashing were assessed. Tannin content correlated significantly and negatively with wort extract and fermentable sugars (p<0.001) and free amino nitrogen (FAN) (p<0.1). This is attributable to inactivation of the exogenous enzymes by the tannins during the mashing process. However, the Type II tannin sorghums had wort quality attributes closer to the non-tannin sorghum types, probably due to their relatively low tannin content (≤1%). Malting gave a great improvement in wort extract, fermentable sugars and FAN but substantially influenced wort sensory properties in terms of higher sourness, bitterness and astringency as well as the expected more malty flavour.Worts from raw red non-tannin sorghums were similar to those of white tan-plant sorghums in both physico-chemical and sensory quality. Thus, red non-tannin sorghums, in view of their better agronomic quality, have considerable potential as whole grain adjunct in lager brewing.

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“…Transmission electron microscopy (TEM). Sorghum grains were sectioned and then prepared for and viewed by TEM as described 12 . Protein bodies in the sub-aleurone layers of the normal and high protein digestibility sorghums were compared.…”

Section: Analysesmentioning

confidence: 99%

“…These results are in agreement with those for sorghum malts mashed on their own (Table II) and show that under a wide range of conditions FAN production from HPDS during mashing was only slightly higher than from NPDS. It is probable that the wet-heat treatment of mashing still caused intermolecular disulphide-bonded cross-linking of the kafirin proteins 4,12 in these HPDS, which reduces the susceptibility of kafirin to hydrolysis 3 .…”

Section: Raw Grain Maltmentioning

confidence: 99%

Influence of High Protein Digestibility Sorghums on Free Amino Nitrogen (FAN) Production during Malting and Mashing

Mugode¹,

Portillo²,

Hays³

et al. 2011

Journal of the Institute of Brewing

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In sorghum brewing, obtaining sufficient Free Amino Nitrogen (FAN) for rapid and complete fermentation remains a problem due to the high proportions of unmalted sorghum used and the poor digestibility of wet-heat treated sorghum protein. Sorghum mutant lines with high protein digestibility have been developed through breeding. These high protein digestibility sorghums (HPDS) have protein bodies with villi-like borders that apparently facilitate protease access. This work investigated FAN production from HPDS when malted and mashed, to assess their potential for use in sorghum brewing to improve wort FAN levels. When malted, HPDS contained substantially higher levels of FAN than normal protein digestibility sorghums (NPDS), 32 mg/100 g malt more. However, when the HPDS were mashed either as malt, or as grain or malt plus exogenous proteases, FAN production during mashing was not substantially higher than with NPDS subjected to the same treatments, only 6, 6-18 and 9-13 mg/100 g grain or malt, respectively. This is probably due to wet-heat induced cross-linking of the kafirin proteins reducing their susceptibility to proteolysis. Notwithstanding this, HPDS could be very useful for improving FAN levels in sorghum brewing if they are malted.

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Proteolysis of Sorghum Endosperm Proteins when Mashing with Raw Grain Plus Exogenous Protease and Potassium Metabisulphite

Cited by 18 publications

References 26 publications

Potential for improvement in yeast nutrition in raw whole grain sorghum and maize lager brewing and bioethanol production through grain genetic modification and phytase treatment

Potential for improvement in yeast nutrition in raw whole grain sorghum and maize lager brewing and bioethanol production through grain genetic modification and phytase treatment

Influence of sorghum grain type on wort physico-chemical and sensory quality in a whole-grain and commercial enzyme mashing process

Influence of High Protein Digestibility Sorghums on Free Amino Nitrogen (FAN) Production during Malting and Mashing

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