富含多酚高粱茶的工艺研究

研究高粱茶加工过程中各加工单元对高粱中多酚含量的影响。结果表明,正交实验优化的最佳工艺参数为:浸泡料液比1∶10,浸泡温度10℃,浸泡时间4 h,蒸料时间45 min,干燥温度为100℃,干燥时间为1 h,焙烤温度为185℃,焙烤时间为35 min。高粱茶产品的色泽呈土黄色,具有焙烤的焦糊香气,多酚物质保留多,表现出较强的抗氧化能力。     

甘薯活性多糖抗突变作用的体外实验研究

为了探讨甘薯的保健作用,本文利用鼠伤寒沙门氏菌营养缺陷型回复突变试验（Ames试验）对甘薯活性多糖进行了体外抗突变作用的研究。结果表明：甘薯活性多糖具有显著的抗突变作用,当其剂量为20mg/平皿时对2－AF、B[a]p和AFB1的致突变性抑制率均达到70％以上,并且呈明显的剂量－效应关系;甘薯活性多糖的抗突变作用主要是通过阻断致突变物使正常细胞变为突变细胞而实现的,也包括部分去突变作用,但促进突变细胞修复的作用不明显;随着121℃高温处理时间和紫外光（30W,25cm)照射时间的增加,甘薯活性多糖的抗突变作用有所减小,而在pH3．5－pH7．5下处理30min后对其抗突变作用影响不大,超过这个pH范围,抗突变作用都有所减小。     

抗突变保健食品的研究进展

食物中的抗突变成分在预防和减少肿瘤形成中起着重要作用,本文系统地介绍了抗突变保健食品的评价方法,国内外研究中已检测出的食物抗突变成分及抗突变机理,目前研究中存在的问题,旨在为抗突变保健食品的开发和研制提供参考。     

大麦麸皮多酚类提取物抗氧化活性和抗突变性

大麦麸皮含有以原飞燕草色素等原花色素为主的多酚类物质。该多酚类提取物和原飞燕草色素具有抑制亚油酸氧化能力,用TBA法和硫氰酸铁法比较,其效果等于或低于BHA和BHT,但高于生育酚和抗坏血酸。与儿茶素类比较,原飞燕草色素对红细胞空壳、微粒体和LDL脂质抗氧化作用及对超氧化物和DPPH自由基消除作用,均优于原矢车菊色素,而与(-)-ECG和(-)-EGCG相当。此外,原飞燕草色素具有比原矢车菊色素更强抑制MNNG和Trp-p-1抗突变性,但略低于(-)-EGCG和(-)-EGC。     

Starch properties as affected by sorghum grain chemistry

To determine the relationship between sorghum grain polyphenol content, grain structure, and starch properties, starch was isolated from 10 sorghum varieties using an alkali steep and wet‐milling procedure. SV2, a tannin‐free variety with white pericarp, gave a white starch. Varieties having red or white pericarp and higher polyphenol levels gave pink starches. Hunter colour values (L, a, b) of starches were not correlated with grain polyphenol content. Grain appearance in terms of pericarp colour, or presence or absence of pigmented testa, did not relate to the intense pink colouration of sorghum starches. Starch amylose content was significantly negatively correlated (r = −0.88, p < 0.001) to grain floury endosperm texture. Sorghum starches had higher peak viscosity (PV) in pasting than commercial maize starch. The time taken to reach peak viscosity from the initial viscosity rise was less for sorghum starches than maize starch. However, sorghum starches had a higher rate of shear thinning (R_st) than maize starch. There was a significant positive correlation between grain polyphenol content and starch PV (r = 0.75, p < 0.05). Starch gel hardness was negatively correlated to pasting properties of R_st and paste breakdown (r = −0.78 and −0.77 respectively) at p < 0.01. Peak gelatinisation temperature (T_p) occurred over a narrow range from 66 to 69 °C. T_p was negatively correlated to the floury endosperm portion of the grain (r = −0.77) at p < 0.01. It is concluded that sorghum grain polyphenol content and grain characteristics influence its starch properties. © 2000 Society of Chemical Industry     

Antimutagenicity and mutagen-binding activation of mutagenic pyrolyzates by microorganisms isolated from japanese miso

The microbiological flora of miso, a traditional fermented food in Japan, were investigated. Bacteria, a yeast and a mould were isolated and identified as Pediococcus acidilactici, Leuconostoc paramesenteroides, Micrococcus halobius, Zygosaccharomyces rouxii and Aspergillus sp. P acidilactici strains were dominant bacteria in miso. The binding and antimutagenic activities of all microbial strains towards mutagenic pyrolysates were investigated. The lyophilised cells of strains of the bacteria and yeast showed the largest antimutagenic effect on 3-amino-l-methyl-[⁵H]pyrido[4,3-b]indole (Trp-P-2), but the mould was less antimutagenic than the bacteria and yeast. Most strains tested had no effective antimutagenic activity against 2-amino-3-methyl imidazo[4,5-f] quinoline (IQ). Trp-P-2 was effectively bound by all non-mould strains but binding of IQ to cells was much less effective. Among the strains tested, Leuconostoc paramesenteroides No 28 indicated the highest binding activity, not only to Trp-P-2 but also to IQ (30% binding capacity). As the concentration of Trp-P-2 was increased, the limits of binding ability of P acidilactici No 23, Z rouxii No 6 and Aspergillus sp 1 were 650, 500 and 400μg per 5 mg respectively. The binding ability and antimutagenicity for Trp-P-2 of all strains was reduced by autoclaving at 100°C for 5 min or 121°C for 15 min, by 6–20% and 7–28%, respectively. Aspergillus sp 1 was unaffected by autoclaving. The binding ability and antimutagenicity of cell walls towards Trp-P-2 was very high, being more than 85 YO effective, but it was lower than that of cytoplasm.     

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。     

Effect of defatting and decortication on distribution of fatty acids,phenolic and antioxidant compounds in sorghum (Sorghum bicolor) bran fractions

Sorghum bran components could be a potential source of nutrients and phytochemicals for industrial applications. The effect of defatting with hexane and different degrees of decortication on distribution of fatty acids, phenolic compounds, colour (L, a and b) and antioxidant activity (DPPH) of red (RS) and white (WS) sorghums was studied. The decortication process was carried out at time intervals of 1–6 min. Defatted and nondefatted fractions were analysed. The content of polyunsaturated fatty acids (PUFA) was higher than monounsaturated fatty acids (MUFA); the content of MUFA was higher than saturated fatty acids (SFA). Linoleic, oleic and palmitic acids predominated in all fractions. Significant differences in the content of palmitic and linolenic acids between sorghums were found. RS had higher content of palmitic, and WS was higher in linoleic acid. Defatted samples contained lower amounts of phenolic compounds and higher antioxidant activities, than nondefatted samples. RS was a better source of total phenolic compounds and antioxidant activity compared with WS, but WS presented a more suitable profile of fatty acids. In conclusion, fractions of both types of sorghums can be used in cereal‐based products to enhance their phytochemical profile.     

Antimutagenicity of curcumin and related compounds against genotoxic heterocyclic amines from cooked food: The structural requirement

Curcumin (a major constituent of widely-used spice and colouring agent, turmeric) was found to be very effective in antagonising the S9-mediated mutagenicity of several food-derived heterocyclic amines. In order to understand the chemical basis of antimutagenic properties of curcumin against these mutagens, we have studied the structure–activity relationship between curcumin and its naturally-occurring derivatives, namely demethoxycurcumin and bisdemethoxycurcumin, and other structurally-related natural and synthetic analogues of curcumin, namely tetrahydrocurcumin, dibenzoylmethane, dibenzoylpropane, vanillin, ferulic acid, isoferulic acid and caffeic acid, using Ames Salmonella/reversion assay, against different classes of cooked food mutagens. We conclude that unsaturation in the side chain, a methoxy group on the benzene ring and a central β-diketone moiety in the curcumin molecule are the important structural requirements responsible for high antimutagenic potential of curcumin against cooked food heterocyclic amines.     

Effect of malt pretreatment on phytate and tannin level of two sorghum (Sorghum bicolor) cultivars

The seeds of two cultivars of Sudanese sorghum (Sorghum bicolor), namely Wad Ahmed and Tabat, were germinated for 4 days to obtain 1‐, 2‐ and 4‐day‐old malts. Sorghum malt (5% and 10%) was added to sorghum flour. The mixtures were incubated at 30 °C with shaking for 30, 60, 90 and 120 min. Malting loss was very slight for both cultivars and for all incubation periods. Phytic acid and tannin contents were assayed for all treatments. The results revealed that phytate and tannin contents were significantly (P ≤ 0.05) reduced when sorghum flour was pretreated with malt. When a mixture containing 10%, 4‐day‐old malt and sorghum flour was incubated for 120 min, it significantly (P ≤ 0.05) reduced phytate and tannin contents by 92% and 98%, respectively, for Wad Ahmed cultivar, while for Tabat they were reduced by 93% and 96%, respectively. The rate of reduction of phytate and tannin content increased with incubation time and malt age and concentration.     

Extraction of polyphenols and hydrolysis of birdproof sorghum starch

The presence of polyphenols in the testa and pericarp of birdproof sorghum has an inhibitory effect on enzyme activity during hydrolysis of sorghum starch. In this communication the effect of different NaOH concentrations at various temperatures on the extraction of polyphenols from birdproof sorghum is described. It was found that a 0.25 M NaOH solution extracted all the polyphenols within 75 min at 22°C. The enzymic hydrolysis of birdproof sorghum starch (without polyphenols) was also investigated. A recovery of up to 92±0.6% glucose from the available starch was obtained. The change in sugar composition during hydrolysis was monitored by h.p.l.c.     

Induction of chitinase in response to Aspergillus infection in sorghum (Sorghum bicolor (L) Moench)

Chitinase is an antifungal protein which is induced in higher plants during infection and stress. In this paper the induction of chitinase activity in response to infection by Aspergillus parasiticus (NRRL 2999) in six sorghum (Sorghum bicolor (L) Moench) genotypes and its association with aflatoxin production were investigated. Chitinase was induced in all six genotypes (two each of red, yellow and white sorghum) when infected by A parasiticus (NRRL 2999). The induction of chitinase activity was highest in the white cultivars, followed by the yellow and red genotypes, compared with healthy grains. In the white cultivars the chitinase activity increased on the 6th and 9th days after infection and was four‐ to fivefold higher than in healthy grains. The total aflatoxin produced was lower in the red genotypes than in the yellow and white genotypes. The white genotypes showed maximum total aflatoxin production at 6 days after infection. The aflatoxins produced in the white genotypes were comparable to those in the red genotypes. There was a significant positive correlation between chitinase activity and aflatoxin production in red sorghum (r² = 0.600, p ≤ 0.001) and white sorghum (r² = 0.411, p ≤ 0.001). Maximum chitinase activity was observed on day 12 in all genotypes under healthy conditions. Copyright © 2004 Society of Chemical Industry     

Isolation of 3 flavonoids from Mentha longifolia (L.) Hudson subsp. longifolia and determination of their genotoxic potentials by using the E. coli WP2 test system

Flavonoids, abundant in most of plant species, are widely used in medicine and development studies on phytotherapeutic drugs due to their various biological activities. In the present study, 3 flavonoids, apigenin-7-O-glucoside, apigenin-7-O-rutinoside, and apigenin-7-O-glucuronide, were isolated from Mentha longifolia (L.) Hudson subsp. longifolia by using E. coli WP2 genotoxicity assay guided fractionation procedures. Later, the mutagenic and antimutagenic properties of each flavonoid were evaluated by using the same genotoxicity assay. The results showed that all the test compounds have significant antimutagenic activity at tested concentrations with or without S9 activation. The inhibition rates were between 25.3% (apigenin-7-O-glucoside with S9-2.0 μM/plate) and 59.0% (apigenin-7-O-rutinoside without S9-2.0 μM/plate). In conclusion, the results revealed that the 3 flavonoids from Mentha longifolia (L.) Hudson subsp. longifolia have significant antimutagenic activity, and the findings of the present study are valuable for further investigations, focus on the phytotherapeutic drug discovery. PRACTICAL APPLICATION: Apigenin derivatives can be thought as genetically safe at tested concentrations because they did not show mutagenic activity. Furthermore, they have also significant antimutagenic activity. These are valuable for further research focus on phytotherapeutic drug discovery and development.     

Appropriate sample for determination of protein in sorghum (Sorghum bicolor (L.) Moench) raised in agricultural trials

Sampling of cereal foods from bulk samples for analyses of nutrients is a well-known procedure, but a satisfactory sampling scheme for such analyses from breeding and agronomic trials has not been defined. However, selection of five plants from each experimental plot is a common procedure among agricultural scientists. The validity of using grains from such a sample for analysis of protein was tested in the present investigation. Values obtained by analysis of pooled samples of five randomly selected ear-heads or the average values of five such ear-heads were not significantly different from those obtained by analyses of sampled aliquots from net plot.     

十二种中国高粱的高粱蜡和高级烷醇含量分析

从全国各主产区采集12种有代表性的高粱样品,测定高粱籽粒中蜡和高级烷醇的含量,结果显示,高粱籽粒中蜡含量在0.2050%～0.3700%之间,其中内杂5号、白杂8号和辽杂1号等品种的高粱蜡含量较高。高粱籽粒中二十八烷醇含量为0.0304%～0.0778%,吉林吉杂97、吉林四杂1号和天津杂交高粱等为二十八烷醇含量较高的品种。高粱籽粒中含有三十烷醇0.0351%～0.0922%,其中吉杂97、四杂25号和辽杂1号等为三十烷醇含量较高的品种。     

Effects of phenolics in sorghum grain on its bitterness,astringency and other sensory properties

Despite the fact that condensed tannins are potentially important antioxidants, there is a general belief that tannins in sorghum confer objectionable sensory attributes. The objective of this study was to determine differences in the sensory attributes of sorghums containing different levels of total phenolic compounds. A trained sensory panel described and quantified the sensory attributes of different sorghums (condensed‐tannin containing and tannin‐free). All the sorghum cultivars were perceived as bitter and astringent. Bran infusions of tannin sorghums were perceived as darker, clearer, more bitter and more astringent than those of the tannin‐free sorghums, while those of tannin‐free sorghums were perceived as sweeter and cloudy. Sorghum whole‐grain rice from the tannin sorghums which had relatively soft endosperm texture (PAN 3860 and Ex Nola 97 GH) was perceived as dark, hard, chewy, bitter and astringent, while that from tannin‐free sorghums having relatively hard endosperm texture (Segaolane and Phofu) was perceived as soft, sweet and had a maize‐flavour. Surprisingly, the bitterness and astringency, as well as other sensory attributes of NS 5511 (tannin sorghum), were perceived as similar to PAN 8564 (tannin‐free sorghum) even though NS 5511 had more than twice the total phenol content of PAN 8564. This suggests not all condensed‐tannin containing sorghums have objectionable sensory attributes. Copyright © 2007 Society of Chemical Industry