Quality Assessment of Different Sorghum Varieties for Their Brewing Potential

Four sorghum varieties (SK 5912, KSV 4, KSV 8, ICSV 400) were malted and extracted under similar conditions to assess their quality for brewing. The results showed that, in general, the sorghum varieties had high malting loss which was attributed to the high germination temperature used. The sorghum varieties also developed low levels of amylolytic activity (α‐amylase and β‐amylase), and with similar ratios. When the sorghum malts were mashed at different temperatures with the aid of commercial enzyme preparations, it was observed that mashing temperatures were more important in sugar release than additions of commercial enzymes. This was because at the lower mashing temperature, sorghum starch was not adequately gelatinised. However, when commercial enzyme preparations were added, low levels of enzymes were very effective in reducing wort viscosity and producing free amino nitrogen (FAN). Although, both commercial enzyme preparation and mashing temperature influenced sugar production, the malts produced glucose and maltose at similar ratios. Therefore good quality malts can be produced from sorghum, however mashing will employ commercial enzymes and mashing regimes are not yet optimised.     

DURATION OF FINAL WARM STEEP AS A CRUCIAL FACTOR IN PROTEIN MODIFICATION IN SORGHUM MALTS

Cold water soluble protein (CWS-protein), cold water soluble protein modification index, total non-protein nitrogen (TNPN), small peptide accumulation, free alpha amino nitrogen, carboxy-peptidase and proteinase activities, all protein modification indicators in malts from two improved Nigerian sorghum cultivars were estimated after six days of malting. Grains were steeped in distilled water for a total of 48 h under four different final warm steep (40°C) treatment periods. Cultivar and duration of final warm water steep, plus their pair-wise interactions highly significantly influenced all these protein modification indices. Sorghum ICSV 400 generally exhibited higher FAN, CWS-protein solubilising activity and accumulation, superior amylolytic potential over proteolysis and better protein modification potential over KSV 8. Lower TNPN and TNPN-FAN difference exhibited by ICSV 400 in spite of its higher FAN suggests superior anabolic protein turnover probably due to more efficient peptide translocation process. Proteolytic activities recorded for both cultivars were inconsistent with levels of N-substances obtained suggesting roles for factors other than proteolysis in grain protein modification.     

EFFECTS OF AIR REST PERIOD ON THE MOBILISATION OF SORGHUM RESERVE PROTEINS

The influence of air rest treatment period on the mobilisation of storage proteins of two improved Nigerian sorghum cultivars ICSV 400 and KSV 8 was evaluated. Grains were steeped in distilled water for a total period of 48 h at 30°C with a 6 h final warm steep at 40°C under four different cycles incorporating 1, 2, 3 or 4 h air rest period respectively. Cold water soluble protein, cold water soluble protein modification index, total cold water solubles, total free alpha amino acid nitrogen, carboxy-peptidase and proteinase activities were determined after 6 days malting. All these protein modification indices were highly significantly affected by length of air rest and cultivar, plus their pair-wise interactions. The levels of all these variables were also higher in sorghum cultivar ICSV 400 compared to KSV 8 except for proteinase activity. Significant differences in grain storage protein complexity and structure coupled with probable differences in key proteinase iso-forms are advanced as possible explanation for the higher proteinase activity recorded in KSV 8 malts.     

Physicochemical,techno-functional and structural properties of gluten-free crackers developed from sorghum (Sorghum bicolor (L.)) varieties

The present study was conducted to develop gluten-free crackers using six different white varieties of sorghum, namely CO30, K12, Parbhani Moti (PM), Parbhani Shakti (PS), ICSV15021 and M35-1. The physico-chemical, mineral and functional properties of developed crackers were studied. The crackers from soft wheat flour serve as a control. Highest protein (7.35 g/100 g), iron (6.63 mg/100 g) and potassium (199.86 mg/100 g) were found in ICSV15021 crackers, whereas highest total dietary fibre (9.01 g/100 g), magnesium (31.13 mg/100 g), copper (1.47 mg/100 g), zinc (1.92 g/100 g) and manganese (1.32 mg/100 g) were found in PS crackers. All exhibited A-type crystallinity pattern except PS crackers (V-type pattern). Overall acceptability of K12 sorghum crackers was found to be similar to control. In conclusion, this study evidenced that gluten-free sorghum crackers exhibited higher nutrients and mineral composition and can be regarded as health-promoting functional food, which is also cost-effective than commercially available gluten-free products.     

Relationship between some Sorghum Malt Quality Characteristics and Nature of Alkaline Steep Liquor

Two Nigerian sorghum cultivars, SK5912 and ICSV400 were used to evaluate the relationships between nature of alkaline steep liquor and some malt quality characteristics over a five day germination period. Patterns of development of the malt quality indices examined were significantly influenced by the nature of alkaline steep liquor, cultivar and duration of germination, plus all their possible interactions at p<0.001. Maximum diastatic activity development was attained in ICSV400 and SK5912 when grains were steeped in NaOH and Ca(OH)₂ respectively. Ca(OH)₂ treatment seemed to cause significant enhancement of diastatic enzyme development in SK5912 compared to other treatments presumably due to Ca²⁺ stabilisation of α-amylase. Mean malt cold water extract (CWE) and hot water extract (HWE) were generally similar within both cultivars for the treatments except for ICSV400 where CWE appeared to be remarkably enhanced by NaOH treatment. Data on cold water soluble carbohydrates (CWS-Carbohydrates), CWS — Carbohydrate/CWE and CWS — Carbohydrate/HWE ratios showed that solubilised carbohydrate matter produced during malting constituted significantly higher proportion of total HWE in ICSV400 in contrast to SK5912.     

Variety and germination time effect on total β‐glucan,water‐insoluble β‐glucan,water‐soluble β‐glucan components and β‐glucanase levels in improved sorghum varieties SK5912, KSV8 and ICSV400 before and after malting and their relationships to wort viscosity

The effects of variety and germination time on β‐glucan components – total β‐glucan (TBG), water insoluble β‐glucan (WIBG) and water soluble β‐glucan (WSBG) and β‐glucanase (BG) levels – before and after malting in improved sorghum varieties SK5912, KSV8 and ICSV400 and their relationships to wort specific viscosity (SV) were studied. This study was part of efforts to aid local malting and brewing industries in the application of sorghum varieties that are abundantly available to reduce costs. At the fifth day of germination, variety ICSV400 had the lowest TBG, WIBG and WSBG levels in its raw and malt samples. Variety SK5912 had the highest TBG, WIBG and WSBG levels in its raw samples, while variety KSV8 had the highest levels of TBG, WIBG and WSBG in its malt samples. Similarly, variety ICSV400 malts developed the highest BG levels, while the KSV8 malts gave the lowest level. The effect of variety, germination time and variety × germination time interaction was significant (p < 0.05) on the TBG, WIBG and BG levels and was not significant on the WSBG levels. Weak and significant correlation of TBG levels with SV (0.25, p < 0.05 for SK5912; 0.24, p < 0.05 for KSV8; and 0.31, p < 0.05 for ICSV400) was observed in all the samples, suggesting that the low β‐glucan levels may not be primarily and solely responsible for any viscosity impediments associated with sorghum worts during run‐off. With improvement in the effective utilization of sorghum, ICSV400 appeared the most suitable variety for malting and brewing in Nigeria.Copyright © 2016 The Institute of Brewing & Distilling     

ENHANCEMENT OF AMYLOLYTIC POTENTIAL OF SORGHUM MALTS BY ALKALINE STEEP TREATMENT

The effect of alkaline steep liquor on sorghum maltability was investigated using three improved Nigeria sorghum cultivara. Germination was for four days at 30°C after steeping under four different regimes. Grain germinability, root length and malting loss were significantly (P < 0.001) repressed by steeping in alkaline liquor for all the cultivars. However, the extent of this repression seemed in all cases significantly dependent on cultivar and steep regime plus their possible interactions. Similarly, the development of diastatic enzymes activities appeared to be highly significantly dependent on steep liquor, steep regime, cultivar, plus their possible pairwise and three way interactions. For ICSV400, highest diastatic power and α-amylase development were attained on steeping grains in alkaline liquor under a continuous steep regime incorporating final warm steep treatment. Conversely, exposure of KSV8 and SK5912 to a regime incorporating air-resting and final warm steep significantly enhanced diastatic power and α-amylase development. β-Amylase activity was in all cases enhanced by alkaline steeping. In fact, β-Amylolytic activity constituted over 70% of total diastatic activity in most alkaline steeped ICSV400 malts. However, SK5912 exhibited relatively low hot water extract in spite of the improved amylolytic activity.     

Current Developments in Malting and Brewing Trials with Sorghum in Nigeria: A Review

Initially, large‐scale lager beer brewing with sorghum malts proved highly intractable due to a number of biochemical problems including: high malting losses estimated at 10–30% as against 8–10% for barley; high gelatinisation temperatures which limited starch solubilisation/ hydrolysis by the amylolytic enzymes during mashing; low extract yield/low diastatic power (DP) due to inadequate hydrolytic enzyme activities especially β‐amylase; low free α‐amino nitrogen (FAN) due to inadequate proteolysis limiting yeast growth during fermentation; high wort viscosities/beer filtration problems due to low endo‐β‐1,3; 1–4‐glucanase activities on the endosperm cell walls causing the release of some β‐glucans. Strident research efforts using improved Nigerian sorghum malt varieties (SK5912, KSV8 and ICSV400) have reported some encouraging results. The knowledge of the biochemical integrity of the endo‐β‐glucanases of the sorghum malt is helping to elucidate their mode of activity in the depolymerisation of the β‐glucans. This is bound to ensure process efficiency in sorghum beer brewing, reduce beer production costs and ultimately, produce a Pilsner‐type of lager beer with 100% sorghum malt.     

Nutritional Quality of Sorghum Seeds: Storage Proteins and Amino Acids

One sorghum commercial genotype (MASSA 03) and nine ICRISAT high-lysine genotypes from India were analyzed for storage protein content, distribution profile, and soluble amino acid concentrations. Storage proteins fraction were extracted and separated by SDS-PAGE. Soluble amino acids contents were determined by HPLC. Variations in intensity and appearance and disappearance of protein bands were observed among the sorghum genotypes suggesting genetic variability. Amino acid profile also indicated large variations in the amino acid concentrations. The high lysine and threonine soluble concentrations observed in the seeds of the sorghum genotypes encouraged the use of these genotypes as potential food source due to the better balanced amino acids profile.     

EFFECTS OF AIR REST PERIODS ON MALTING SORGHUM RESPONSE TO FINAL WARM WATER STEEP

The effects off various lengths of air rests on response off malting sorghum main root length, malting loss, diastatic activity, α- and β-amyloytic activity and extract to final warm water steep at 40°C was investigated. Grains were steeped in distilled water for a total of 48 h at 30°C with a 6 h final warm water steep under four different cycles incorporating 1, 2, 3 or 4 h air rest periods. All malt quality properties evaluated were significantly affected by the length of air rest, the cultivar and their pair-wise interactions. Main rootlet length and malting loss reduced progressively as the length of air rest increased. Reducing power, α- and β-amylolytic activity and extract generally increased as the length of air rest was increased for both sorghum cultivars ICSV 400 and KSV 8 examined. The steep cycle incorporating 3 h length of air rest was found by experiment to give the optimum levels of malt quality indices analysed while at the same time causing considerable reduction in average main rootlet length and total malting loss for both grain cultivars.     

动植物源蛋白体外消化产物结构性质及ACE抑制活性

为揭示动植物源蛋白对于血压调节功能上的差异是否由蛋白肽的血管紧张素转化酶（angiotensin conversion enzyme,ACE）抑制活性所引起,动植物蛋白经体外消化后,对蛋白肽的ACE活性抑制进行研究。采用胃蛋白酶-胰蛋白酶两步消化法,水解植物蛋白（大米、燕麦、大豆、豌豆）、红肉蛋白（猪肉、牛肉）和白肉蛋白（鸡肉）。测定所获蛋白肽的水解度、分子质量分布、氨基酸组成及其ACE抑制率。结果表明,随着蛋白质水解度的增加和分子质量的减小,3类蛋白消化产物的ACE活性抑制率均相应增大。其中,植物蛋白消化产物ACE抑制率最高（60.41%）,红肉蛋白最低（40.13%）。对蛋白质消化产物的氨基酸组成进行分析,结果表明,植物蛋白和白肉蛋白消化产物的疏水性氨基酸含量均显著高于红肉蛋白。3类蛋白中消化产物的疏水性氨基酸含量越高,则ACE抑制活性越高,说明疏水性氨基酸含量高可能是植物蛋白肽具有高的ACE抑制活性的主要原因之一。     

Grain and malt quality properties of some improved Nigerian sorghum varieties

To determine their grain and malt quality properties, ten improved Nigerian sorghum varieties were subjected to several tests. The parameters that were tested included thousand corn weight, germinative energy, germinative capacity, water sensitivity, malting losses, hot and cold water extracts and free amino nitrogen (FAN). Results obtained showed variations among the sorghum varieties in most of the parameters assessed. While variety SK5912 was heaviest (40.25 g), variety Nafelen 6 had the lowest weight (22.45 g). For germinative capacity, variety KSV8 gave the highest value (97.0%), while variety ICSV400 gave the lowest value (90.5%). Variety KAT487 was the most water sensitive (5%), while four varieties simultaneously gave the lowest value. Boboje gave the lowest malting loss (13.77%), while the highest loss (37.74%) was given by White Kaura. For the extracts, variety SK5912 gave the highest value, as was the case also with FAN. Generally, there were significant differences across the different varieties of sorghum for malting loss, FAN, cold water extract and hot water extract at both p < 0.05 and p < 0.01. The results showed significant agreement with previous reports, with the key findings being that grain size mostly correlated positively with high expression of the critical malting parameters. Copyright © 2014 The Institute of Brewing & Distilling     

Nutritional quality and antioxidant activity of marama-sorghum composite flours and porridges

Marama bean, an underutilised legume in southern Africa, is a good source of protein, fat and phenolic compounds, the latter known to have potential health benefits. Marama flours, sorghum meal, marama-sorghum composite flours and porridges were analysed for proximate composition, amino acid composition, energy value, fatty acid composition, total phenolic content and antioxidant activity. Compositing sorghum meal (70%) with marama flours (30%) significantly increased the protein and fat contents in flours and porridges. Energy values of marama-sorghum composite porridges were 11-24% higher than sorghum porridge. Lysine content was 3-4 times higher in marama-sorghum porridges than in sorghum porridge. There was an increase in oleic acid as sorghum meal was composited with marama flour. There was a positive correlation between the total phenolic content and antioxidant activity in all samples. Use of marama flour in sorghum composite flours and porridges improved the nutritional quality and antioxidant activity.     

PROMOTING SORGHUM RESERVE PROTEIN MOBILISATION BY STEEPING IN ALKALINE LIQUOR

Mobilisation of sorghum storage reserve proteins by steeping in alkaline liquor for 48 h under four different regimes was evaluated. Germination was for 4 days at 30°C. Cold water soluble protein (CWS-protein), CWS-protein modification index, total non protein nitrogen (TNPN), peptide accumulation, FAN, endo- and exo-protease activities—all key indicators of protein mobilisation were highly significantly affected by steep regime, steep liquor and cultivar as well as their pairwise interactions. Mean FAN and TNPN were significantly higher (P < 0.0005) for malts derived from alkaline steep liquor except for KSV 8 which exhibited significant inhibition of TNPN development. Similarly, alkaline steeping promoted protein solubilisation and CWS-protein modification. While parallel improvements in amylolysis and proteolysis were recorded for ICSV 400, proteolysis in KSV 8 and SK 5912 seemed more enhanced except for SK 5912 exposed to air rest cycles. Steeping in alkaline liquor also caused significant repression of the proteases in KSV 8. Conversely, steeping SK 5912 under similar conditions promoted rather than inhibited development of these enzymes. Poor correlation between protein degradation products and enzyme development suggest major roles for factors other than proteolysis in sorghum reserve protein mobilisation.     

Potato Quality as Affected by Source of Magnesium Fertilizer: Nitrogen, Minerals, and Ascorbic Acid

TWO SOURCES of magnesium fertilizer, Epsom salt and dolomite, were compared as to their effect on nitrogen, mineral, and ascorbic acid contents of Katahdin potatoes. Both Mg sources increased significantly (p < 0.05) the total, nonprotein, and protein nitrogen of both cortex and pith tissues. The pith tissue was significantly (p < 0.05) higher than the cortex in total and nonprotein nitrogen. Potatoes fertilized with Epsom salt were higher in nitrogen than those receiving dolomite. Both sources of Mg significantly (p < 0.05) increased Al and Fe contents of tubers, and the greater increase occurred with Epsom salt. Tubers from soils receiving dolomite were significantly (p < 0.05) higher in manganese and cadmium contents than those receiving Epsom salt. No significant differences were observed in ascorbic acid content with either Mg source.     

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

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. Copyright © 2012 The Institute of Brewing & Distilling     

体外模拟胃肠消化过程中山楂的活性成分及抗氧化性规律

为了研究体外模拟山楂胃肠消化过程中的活性成分及抗氧化性变化规律。本实验通过体外模拟山楂口腔消 化液、胃消化液、肠消化液、肠透析液以及山楂提取液5 种样品,测定其黄酮、多酚、多糖和有机酸含量变化,及 5 种样品对1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基、2,2’-联氮-二（3-乙基-苯并噻 唑-6-磺酸）二铵盐（2,2’-azinobis-(3-ethylbenzothiazoline-6-sulphonate),ABTS）自由基、羟自由基清除能力及铁离 子还原能力。结果表明：5 种样品在模拟消化过程中活性成分具有相似的变化趋势,其中经口腔和胃消化后多糖和 有机酸比消化前含量显著增加;5 种样品清除DPPH自由基、ABTS＋?及还原铁离子能力的变化趋势相似,其中口腔 和胃消化液抗氧化能力最强,肠透析液抗氧化能力最弱,而清除羟自由基能力的结果略有不同。从本研究中可以看 出山楂在体内的消化产物具有较好的抗氧化活性。     

Tannins of Grain Sorghum: Luteoforol (Leucoluteolinidin), 3',4,4',5,7-Pentahydroxyflavan

SUMMARY– The principal tannin of sorghum is a leuco-anthocyanin yielding luteolinidin (3',4',5,7-tetrahydroxy-flavylium) when heated with mineral acid. The precursor, luteoforol, has most of the properties of 3',4,4',5,7-penta-hydroxyflavan prepared by reduction of eriodictyol. Luteoforol, when treated with concentrated mineral acid in the cold, gives a purple color with Λ_max550nm. A method for the determination of luteoforol in sorghum, based on this property, is described. The results with a number of varieties of sorghum are compared with those obtained by the AOAC Folin-Denis method. The contribution of luteoforol to the "tannin" so determined varies from 1 to < 25%. Except for one sample of Kaffir corn, which contained leucocyanidin as well as luteoforol, no other tannins were detected. The "tannin" content varied widely, (from 0.05 to 0.67% as tannic acid), a white-skinned variety having the least. The uniformity of commercial samples can be rapidly evaluated by single-grain determinations of luteoforol.     

酶解与体外模拟胃肠消化对脱脂羊奶粉ACE抑制活性的影响

本研究旨在探究商业蛋白酶酶解与体外模拟胃肠消化对高消化率的脱脂羊奶粉释放ACE抑制肽的影响,以评价脱脂羊奶粉酶解必要性及所需酶解程度。采用中性蛋白酶、碱性蛋白酶、复合蛋白酶和风味蛋白酶对脱脂后的圭山羊奶粉进行酶解反应,并对脱脂羊奶粉及其酶解物进行体外模拟胃肠消化,测定酶解液及模拟胃肠消化液的多肽含量、ACE抑制活性以及分子量分布。研究发现,羊奶粉经过体外模拟胃肠消化后,消化液的多肽含量与ACE抑制率分别达到20.81 mg/mL和62.55%;而经过碱性蛋白酶和风味蛋白酶的适度酶解,其模拟胃肠消化液多肽含量与ACE抑制活性反而下降;经过复合蛋白酶的适度酶解,其模拟胃肠消化液的多肽含量与ACE抑制活性小幅度提高,分别达到22.67 mg/mL和69.29%;经过中性蛋白酶的适度酶解,其模拟胃肠消化液多肽含量与ACE抑制活性均显著提高,分别达到23.76 mg/mL和81.10%。分子量分布结果显示,经过体外模拟胃肠消化后,<1000 Da的小分子肽由酶解液中的70.77%提高到90%。综上,圭山羊奶粉经过体内胃肠消化就可以释放出较多的ACE抑制肽,而经过中性蛋白酶酶解至水解度8%后...     

高粱复配米脂肪体外消化产物及其氧化稳定性

为探究高粱复配米脂肪体外消化产物及其氧化稳定性,将熟化高粱与大米按质量比1:4和1:1复配进行模拟体外消化,采用气相色谱-质谱联用法分析复配米饭的脂肪消化产物,并以脂质过氧化物值和丙二醛浓度为指标探究其氧化稳定性。结果表明,1:1和1:4复配米经胃肠液消化后含有25种脂肪酸,主要为棕榈酸、硬脂酸和亚油酸。不饱和脂肪酸占到34.34%和28.50%,人体必需脂肪酸亚油酸和α-亚麻酸含量分别为91.41、3.05和59.36、1.83μg/g,均显著高于大米组（P<0.05）。此外,1:1和1:4复配米消化后肠液过氧化值为33.83和43.16 nmol/g、丙二醛含量为28.17和27.72 nmol/g,总氧化程度均低于高粱组。综上,食用高粱复配米比单纯食用大米改善了摄入的饮食脂肪酸组成,又比单纯食用高粱减少了人体对脂质氧化产物的吸收积累。