Separation and identification of Egyptian sorghum non-tannin polyphenols

The extraction, isolation and identification of the non-tannin polyphenols of both low and high tannin sorghum varieties were studied. The results indicated that both low and high tannin varieties contained 4 identical low molecular weight fractions of non-tannin polyphenols. These fractions were not able to precipitate the gelatin and also gave negative results with the vanillin reagent. The other fractions were 6 in high tannin variety and 5 in low one.     

The effect of sorghum type and processing on the antioxidant properties of African sorghum-based foods

This work determined the effect of sorghum type and different processing technologies of traditional African sorghum foods on total phenols, tannin content and antioxidant activity. The products were prepared by fermentation, conventional and extrusion cooking of whole and decorticated ground grain. The tannin sorghum types, had higher ABTS and DPPH antioxidant activities, compared to the types without tannins. Antioxidant activity was significantly correlated with total phenols and tannins (r > 0.95). Decortication, reduced antioxidant activity of both tannin and non-tannin sorghum by 82–83% due to the removal of the pericarp and the testa, which decreased phenols. Processing, generally decreased antioxidant activity, however, conventionally cooked porridges had higher antioxidant activity than the extrusion cooked products. The retention of antioxidant activity, particularly in fermented and unfermented porridges, means that whole tannin sorghum can be processed into foods with potential health benefits.     

Effect of alkaline pretreatment and cooking on protein fractions of a high-tannin sorghum cultivar

A high-tannin sorghum cultivar (Karamaka) was used to study the effect of soaking in distilled water or 0.05%, 0.10% and 0.20% NaOH for 8 h, and soaking in distilled water or NaOH followed by cooking, on proximate composition, tannin content and protein fractions. Results showed that soaking the sorghum grains in water or NaOH for 8 h caused a slight increase in crude protein, whilst the tannin content significantly (p ? 0.05) decreased. The highest drop in tannin content was observed after soaking sorghum in 0.20% NaOH for 8 h at ambient temperature. Combining soaking and cooking further lowered the tannin content of sorghum, with a maximum reduction of 83.9%. Soaking in NaOH and cooking caused significant (p ? 0.05) increases in the albumin and globulin fractions, accompanied by a significant reduction in the glutelin fraction. This readjustment of sorghum protein fractions would indicate improvement in the quality of sorghum proteins.     

The production of the Chinese baijiu from sorghum and other cereals

Baijiu is a widely consumed spirit usually distilled from fermented sorghum. Here the use of other cereal grains (wheat, corn, rice and barley) is compared with sorghum. The concentration of ethyl acetate in spirit made from sorghum was found to be higher than in the spirits made using other grains, whereas the concentrations of aldehydes and higher alcohols were lower. Based on sensory evaluations, the flavours were more satisfactory when sorghum was used for making Baijiu. Of the other cereals, the flavour from wheat was better than those of corn, rice and barley for making Baijiu. The ester concentration of the spirit made from the rice was low, whereas aldehyde and alcohol contents were high. An abnormal flavour was found in spirits made from corn or barley. Further work with sorghum showed variations in tannin content, and a correlation between the tannin content and brewing performance. When the content of tannin was <1.94%, the ethyl acetate and ethyl octanoate content were positively correlated with tannin content. In contrast, the ethyl lactate and higher fatty acid ethyl esters content were negatively correlated with tannin content. The results of flavour analysis and sensory evaluation indicated that the ideal sorghum tannin content for producing Baijiu was between 1.0 and 2.0%. Copyright © 2017 The Institute of Brewing & Distilling     

Extractability,fractionation and nutritional value of low and high tannin sorghum proteins

Kafirins and glutelins were found to be the major, while albumins and globulins were the minor components of sorghum proteins. Marked differences were noticed in both amino acid composition and electrophoretic properties among the sorghum protein fractions. Albumins and globulins were more rich in most of essential amino acids than the other sorghum protein fractions. Dehulling of sorghum grain led to a marked reduction in tannins, and slight reduction in total protein. Low tannin sorghum, Giza 15 variety, had relatively high levels of protein extraction efficiency, albumins, globulins and kafirins, slightly low levels of glutelins and the same amino acids as the high tannin sorghum SX 121 variety.     

高粱单宁含量对清香型大曲白酒酒醅中细菌种群的影响

利用高通量测序技术对清香型大曲白酒含单宁高粱和不含单宁高粱酒醅中的细菌种群进行了分析,研究了高粱单宁含量对细菌种群的影响。分别采集发酵第1、3、7和21天的酒醅,提取细菌基因组DNA,并扩增了16S rDNA的V4区,扩增产物构建文库并进行高通量测序,测序结果进行生物信息学分析。结果表明,两种酒醅中的主要细菌种群有片球菌属（Pediococcus）、魏斯氏菌属（Weissella）、乳杆菌属（Lactobacillus）、芽孢杆菌属（Bacillus）、拟杆菌属（Bacteroides）、窄食单胞菌属（Stenotrophomonas）等。在发酵的第1天和第3天,不含单宁酒醅的细菌种群多样性高于含单宁酒醅的;但之后却完全相反。单宁含量对细菌种群差异的贡献率为22.39%,芽孢杆菌属（Bacillus）、肠球菌属（Enterococcus）、类芽孢杆菌属（Paenibacillus）与单宁含量呈显著负相关（P＜0.05）。     

Impact of cowpea addition on the Protein Digestibility Corrected Amino Acid Score and other protein quality parameters of traditional African foods made from non-tannin and tannin sorghum

Protein malnutrition is a problem in Africa where sorghum is a staple foodstuff. Improvement in the protein quality of traditional African sorghum (Sorghum bicolor L. Moench) foods through the addition of cowpea (Vigna unguiculata L. Walp), an indigenous African legume, was investigated. Two sorghum cultivars, a red, tannin-type (NS 5511) and a white tan-plant, non-tannin type (Orbit) were complemented with cowpea (70:30 ratio). Ugali (thick porridge), uji (fermented thin porridge) and injera (fermented flatbread) were prepared. The protein lysine scores of cowpea-complemented foods were about double the levels of sorghum-only foods. The in vitro protein digestibility of the foods increased by 13–62%. The increase in lysine and protein digestibility improvement resulted in three- and two-fold improvement in the Protein Digestibility Corrected Amino Acid Score (PDCAAS) of NS 5511, and Orbit foods, respectively. Addition of cowpea to tannin, as well as non-tannin sorghum is a viable option for improving the protein quality of a wide range of traditional African foods.     

Effects of reducing phytate content in sorghum through genetic modification and fermentation on in vitro iron availability in whole grain porridges

Improved iron availability from sorghum porridges will benefit many malnourished communities in rural Africa, where there is a high prevalence of iron deficiency. This research compared the efficacy of reducing sorghum phytate content by genetic modification (GM) and natural lactic acid fermentation on in vitro iron availability in porridges. GM low phytate, non-tannin (38% phytate reduction) and tannin (36% phytate reduction) sorghums and their null controls were processed into thick unfermented and fermented porridges. The inhibitory effect of the tannins seemed to prevent any increase in in vitro iron availability, regardless of the level of phytate reduction. Only the additive effect of GM in combination with fermentation in reducing the phytate content appeared to cause a substantial increase in in vitro iron availability in the GM fermented porridge (30%) made from the non-tannin line, compared to the GM unfermented porridge (8.9%) or the fermented porridge (17.6%) of the control sorghum. This could be of nutritional significance.     

粳糯高粱籽粒理化性质及酿酒特性分析

以6种高粱为材料,对高粱籽粒理化性质、出酒率和酒品质等进行测定,分析不同类型高粱品种酿酒特性。结果显示,糯性高粱籽粒吸水率和膨胀率均大于粳性,其中冀酿2号支链淀粉含量最高,为69.84%。粳性辽杂19容重、含水量、蛋白质含量最大,分别为787 g/L、9.66%、8.91%。粳性高粱淀粉颗粒表面光滑,结构较为松散,糯性淀粉浆起始温度、终止温度和热焓值均高于粳性。粳性辽杂19酒中乳酸乙酯含量最高,为227.98 mg/100 mL,其余酯类糯性的均小于粳性。粳性佳县高粱总淀粉、单宁、酒中乙酸乙酯的含量和出酒率均为最高,分别为77.42%、1.22%、229.29 mg/100 mL和41.61%。该研究揭示了粳糯高粱之间籽粒、淀粉理化性质和蒸煮特性存在较大差异,最终导致不同高粱酒香味物质含量不同,结合出酒率得出佳县高粱较适合于陕西省西凤酒的酿造。     

高粱性质对酿造清香型白酒的影响

高粱是白酒酿造的主要原料,由于品种或产地的因素,高粱性质往往有很大差异。为了研究不同性质的高粱对清香型白酒酿造过程中的工艺参数及所酿白酒品质造成的影响,我们选择了来源不同的两种高粱进行清香型白酒酿造实验。首先,我们对高粱性质进行了检测。然后,通过进行发酵酒醅的品温、水分、15对时酸度、酒精度的跟踪检测以及新产酒产量、总酸、总酯和挥发性组分的检验,并利用生物统计方法进行计算,得出两种高粱的玻璃质层的厚度、粗蛋白、粗脂肪、直链淀粉、支链淀粉及单宁含量等具有较大差异。此外,高粱性质的差异导致酒醅水分和品温差异,而且对新产酒中醇类物质的含量影响较大,对新产酒产量、酸酯等影响较小。     

不同品种高粱酿造清香型白酒的香味物质差异及其与理化品质的相关性

该实验以3种高粱（泸州红1号、金糯梁1号、澳洲AZ）为原料在不同酒厂开展清香型白酒酿造试验,通过测定香味物质含量解析不同酒样的香味物质组成差异并分析其与高粱理化成分的相关性。结果表明,酒样香味物质含量的结构组成受酒厂、高粱品种及两者交互作用的影响。从不同酒样中获得11个较可靠的差异香味物质;高粱的单宁和支链淀粉含量对酒样香味物质的含量及其结构组成具有显著影响（P<0.05）,以两者为自变量建立预测差异香味物质含量的回归方程,对预测变量的解释度为29.20%～66.30%。该结果可为酿酒高粱的选育应用提供依据,也突显开展多酒厂、多批次酿造试验评价酿酒效果的必要性。     

Effect of milling time on antioxidant compounds and activities of methanol extracts of sorghum [Sorghum bicolor (L.) Moench]

Antioxidant compounds and activities of methanol extracts of sorghum for different milling times were investigated. Total polyphenol, flavonoid, and tannin contents were measured using spectrophotometric methods. Methanol extracts were also evaluated for antioxidant activities based on DPPH and ABTS radical-scavenging activities. As milling rates increased, milling recovery and a value decreased, while L and b values increased. The extraction yield, antioxidant compound contents, and antioxidant activities of sorghum grain decreased with increasing milling rates. Methanol extracts from sorghum bran generally showed higher antioxidant activities than extracts from sorghum grain. The antioxidant content was higher in sorghum bran extracts than in grain extracts. A significant (p<0.05) correlation was observed between free radical-scavenging activity and the content of polyphenolic compounds. Sorghum bran exhibited antioxidant activities that may have important health benefits.     

Sorghum kafirin interaction with various phenolic compounds

The ability of various phenolic compounds to bind and precipitate kafirin, the prolamin protein of sorghum, was investigated with regard to effects on its nutritional and functional uses. The protein–phenolic compound interaction was quantified by haze formation and colorimetric determination of total polyphenol bound. Ferulic acid, catechin and extracted phenolics (flavonoids) from condensed tannin‐free sorghum did not complex kafirin. Only tannic acid and sorghum‐condensed tannins had the ability to complex kafirin. The sorghum‐condensed tannins interacted more strongly than tannic acid. The haze of sorghum‐condensed tannins–kafirin was permanent, indicating a strong interaction. The fact that sorghum‐condensed tannins can bind irreversibly to kafirin indicates that this may play a role in decreasing protein digestibility in high‐tannin sorghum and can cause haze formation in lager beer made from high‐tannin sorghum. However, in condensed tannin‐free sorghum, phenolic compounds may not appear to play a major role in decreasing protein digestibility, as these endogenous phenolics may not bind with kafirin. Copyright © 2003 Society of Chemical Industry     

Comparison of extraction methods and assay procedures for the determination of the apparent tannin content of common beans

The biological utilisation of legume seeds is limited by the presence of polyphenols, among other antinutritional factors. Tannins, compounds of the complex polyphenol family, interact with dietary proteins and digestive enzymes, decreasing the nutritional value of ingested foods. The quantification of polyphenols in grains and seeds is problematic due in part to the diversity of methods used and the presence of interfering factors. In this study the most commonly used assay procedures were compared and validated. Black bean polyphenols, fractionated by adsorption chromatography into tannins and non-tannins, were assayed with Prussian blue, Folin-Denis, and corrected and uncorrected vanillin tests. The results obtained suggest that the Prussian blue assay is the most convenient for tannin determination. In spite of its low specificity it reacted preferentially with this polyphenol group and correlated well with the other procedures. Neither the corrected nor the uncorrected vanillin assay is recommended for use in beans due to interference by non-tannin compounds present in raw extracts.     

高粱对酱香型白酒品质影响的研究进展

酱香型白酒属于纯粮固态发酵酒类,高粱作为原料是影响酱香型白酒品质的主要因素之一,其出酒率、风味、功能性等品质与酒用高粱原料的淀粉、蛋白质、脂质、单宁、香气成分等的含量息息相关。本文概述了酒用高粱种植与发展的基本情况,并深入探讨了酒用高粱的物理性质、营养组成和酿造性能,对研究酒用高粱原料与酱香型白酒品质间的关系具有重要意义。     

南北方几种高粱酿酒品质分析

对南北两地6个不同品种高粱的理化指标和酿造性能进行了检测。结果表明,6种高粱的淀粉和蛋白质含量都比较相近,差异在于其中的3种糯红高粱的直链淀粉均未检出,且支链淀粉含量很高,粗脂肪和单宁含量也较高,而3种北方粳高粱直链淀粉与支链淀粉比例接近,为1∶4.3,粗脂肪和单宁含量均较低。对样品高粱的吸水性能、糊化温度以及粘度进行检测,结果表明,其中的3种糯红高粱更适于酿酒。     

汽爆高粱全粉馒头的研制

目的:研究汽爆对高粱功能成分的影响以及汽爆高粱全粉添加量对面团和馒头质构特性的影响。方法:汽爆高粱以蒸汽为汽爆介质,研究0.8 MPa压力维压5 min的条件下高粱中功能成分的变化;将汽爆高粱全粉按不同比例添加到小麦面粉中制作馒头,用质构仪测定面团和馒头的质构特性,用白度仪测定馒头白度值,对馒头食用品质进行感官评价,并讨论了汽爆高粱全粉的适宜添加量。结果表明:高粱经汽爆处理后,高粱中的功能成分含量发生变化:不溶性膳食纤维和单宁含量明显下降,抗性淀粉、总多酚和总黄酮含量提高。添加适量的汽爆高粱全粉可改变小麦面团的特性及馒头的品质,在本实验中汽爆高粱全粉的适宜添加量为25%,此时硬化速率低,馒头的食用品质较好。结论:汽爆有利于降解不溶性膳食纤维和单宁含量,促进功能成分的溶出,抗性淀粉、总多酚和黄酮含量增加;汽爆高粱全粉可以添加到馒头中,可以为高粱的开发利用提供参考。     

Localization of phenolic acids and antioxidant activity in sorghum kernels

White and red of sorghum grains were sequentially pearled into 11 pearling fines and the corresponding 11 pearled kernels to study the localization of phenolic acids within sorghum grains. All fractions were analyzed for phenolic acids content by HPLC and antioxidant capacity by FRAP assays. Four phenolic acids identified in all fractions were caffeic, p-coumaric, ferulic, and sinapic acids. Data showed that the distribution of phenolic acids and antioxidant capacity in two sorghum genotypes was heterogeneous. Around 60% of the phenolic acids and the antioxidant capacity were recovered in the initial three pearling fine fractions that constituted about 20% surface removal. The concentrations of the phenolic acids decreased significantly with sequential pearling. Significant correlation between total phenolic acids and antioxidant capacity was observed with all fractions except for the first pearling fines from the red sorghum.     

单粮和多粮型白酒发酵过程的成分差异分析

为探索单粮（高粱）酿造和多粮（高粱、大米、小麦、糯米和玉米）酿造的白酒在发酵过程中挥发性成分的差异,采用顶空固相微萃取、液液微萃取结合气相色谱-质谱对不同原料酿造的馥合香型白酒酒醅中挥发性成分进行鉴定。结果表明：在两种酒醅中均检测到86?种挥发性成分,单粮酒醅中生成更多的酚类和酸类化合物,多粮酒醅中生成更多的醇类和含氮化合物。比较两种酒醅中关键差异化合物发现,单粮酒醅发酵生成更多的苯乙醛;而多粮酒醅发酵生成更多的乙酸己酯、肉豆蔻酸乙酯、苯甲醇、6-甲基-2-乙基吡嗪和2,3,5-三甲基吡嗪。除上述吡嗪类化合物以外,多粮酒醅中吡嗪类化合物总含量显著高于单粮酒醅（P＜0.05）,这可能是多粮酒醅不同于单粮酒醅的典型特征。     

不同品种高粱酿造浓香型白酒的香味物质组成差异及其影响因素

在两个酒厂对四种酿酒高粱开展浓香型白酒的多批次大生产酿造试验,采用高效气相色谱技术检测酒样香味物质含量,探究不同高粱酒样的香味物质组成差异及其影响因素。结果显示,酒样香味物质的结构组成受到酒厂、酿造批次和高粱品种等因素的影响,其中酿造批次的影响大于高粱品种。不同高粱酒样的差异香味物质种类及其数量随酒厂和酿造批次的不同而不同,从中筛查到6种较可靠的差异香味物质(2-甲基丁醇、仲丁醇、异丁醇、异戊醇、甲醇、丙酸),其中北方杂交粳高粱酒样的杂醇油含量明显高于糯高粱(金糯梁1号和机糯梁2号)。酒样香味物质的结构组成、酯类与醛类的总量以及丙酸和甲醇的含量均受入窖酒醅酸度的显著影响(P<0.05)。高粱的单宁含量显著影响醛类和异丁醇的含量(P<0.05),支链淀粉含量显著影响仲丁醇的含量(P<0.05)。获得了基于酒醅和高粱的理化成分为自变量预测差异香味物质含量的多元回归方程,对预测变量的解释度(R²)分别为23.00%～51.00%和14.60%～18.80%。本研究结果可为酿酒高粱的品种改良与推广以及酿酒工艺参数的优化完善奠定基础。