水葫芦内生菌分离及真菌代谢产物初探

从水葫芦的根茎叶器官中分离纯化出7株内生菌（6株细菌,1株真菌）,经分子生物学鉴定,内生真菌为毛霉科匍枝根霉属中的匍枝根霉;并对7株内生菌粗提物以4株细菌（金黄色葡萄球菌、大肠埃希氏杆菌、苏云金芽孢杆菌和枯草芽孢杆菌）和5株农业病原菌（苹果腐烂菌、葡萄白腐真菌、白菜黑斑病菌、棉花枯萎病菌、高粱炭疽病菌）为指示菌株,采用滤纸片法进行抑菌活性测定.结果发现只有内生真菌对4株细菌有一定的抑菌活性,对5株农业病原菌中的葡萄白腐真菌有微弱的抑制活性,而细菌没有表现出明显的抑菌活性.通过对分离获得的内生真菌进行发酵、分离和纯化的研究,并根据质谱和核磁共振等谱学数据鉴定了一个过氧化麦角甾醇的化学结构.     

小米糠多酚提取工艺研究

为了使小米糠得到充分利用，本文以山西省沁县产的晋谷21号小米糠为原料，通过比较超声法、微波法、冷浸法、热回流、闪式法五种提取方法的小米糠多酚得率以及抗氧化能力的大小，选择超声提取法并通过单因素及响应面实验对小米糠多酚提取工艺进行优化，最后使用HPLC-ESI-MS对小米糠多酚成分进行定性分析。结果表明，超声提取得到的小米糠多酚得率最高，为1.55%，浓度6 g/L时对DPPH·自由基的清除率可达80.45%；小米糠多酚的最佳提取工艺条件为：液料比10:1 mL/g、颗粒度60目、提取温度48 ℃、提取时间48 min 、超声功率240 W、乙醇体积分数70%，在此条件下小米糠多酚得率为1.726%；通过HPLC-ESI-MS 分析，小米糠多酚中含有香草酸-4-O-β-D-葡萄糖苷和阿魏酸甲酯[]。     

Optimization of agro‐residual medium for α‐amylase production from a hyper‐producing Bacillus subtilis KCC103 in submerged fermentation

BACKGROUND: Although submerged fermentation (SmF) is the conventional method in industry, use of low‐cost agro‐residues for α‐amylase production in SmF has not been well established. Here we optimized agro‐residue‐based medium and culture conditions for α‐amylase production in SmF using a hyper‐producing Bacillus subtilis KCC103. RESULTS: B. subtilis KCC103 produced α‐amylase in SmF by utilizing agro‐residues. Wheat bran (WB) and sunflower oil cake (SFOC) were selected as the best substrates using shake flasks. Medium containing WB (carbohydrate rich) and SFOC (rich in protein and free amino acids) at 1:1 (w/w) ratio produced high levels (90 IU mL⁻¹) of α‐amylase at 30–36 h in a shake flask. The α‐amylase yield was 14‐fold enhanced (1258 IU mL⁻¹) by optimizing process parameters and medium composition following response surface methodology in a bioreactor. The optimal conditions were: WB 1.27%, SFOC 1.42%, pH 7, 37 °C and 10–12 h. Both in shake flask and bioreactor α‐amylase synthesis was not repressed by the release of simple sugars into the medium. CONCLUSION: KCC103 with catabolite derepression and hyperproducing ability is useful for economic α‐amylase production using low‐cost agro‐residual substrates in conventional SmF. Since the production time (10–12 h) is much shorter than other strains this would improve productivity and further reduce the cost of α‐amylase production. Copyright © 2008 Society of Chemical Industry     

Evaluation of the stability of blends of sunflower and rice bran oil

Blends of sunflower oil (SFO) and rice bran oil (RBO) were evaluated for their stability. Additionally, known amounts of natural antioxidants extracted from RBO were added to SFO, and their protective effect was compared to that of the blends. The results found indicate that by raising the amount of RBO, from 10 to 50%, an increase of OLO, OLP, PPL, OOO, PPO, OPO, 18:1 and 16:0 occurred, followed by a decrease of LLL, LLO, and 18:2. These changes in fatty acid and triacylglycerol (TAG) composition led to an increase of the oil stability index at 120 °C and a reduction of polymer TAG formation in the heated blends at 180 °C during 8 h. A comparable protective effect of natural antioxidants to that of blending was observed in a 50 : 50 blend, by remarkably increasing the induction period.     

应用基因工程改良L-乳酸菌株

以大肠杆菌、酵母茼、乳酸细菌和米根霉等具有代表性的乳酸发酵菌种为例，介绍了基因工程方法在提高L-乳酸产量度纯度等方面的研究进展及取得的成果。     

Texture and other Physicochemical Properties of Whole Rice Bread

ABSTRACT: Samples of experimental rice breads baked in a home bread machine were evaluated by physicochemical methods and compared with a local commercial whole-wheat bread. The results showed that rice breads had less specific volume, harder texture, and were more prone to retrogradation during storage than whole wheat bread. All stored breads showed a peak at about 52 °C by differential scanning calorimetry (DSC) analysis, which is characteristic of retrograded starch. However, the δH for rice bread was about 3 times the value of whole-wheat bread, suggesting its strong tendency to retrograde. X-ray diffraction (XRD) evaluation also indicated the appearance of a strong 20 peak between 16.7 °C to 17.0 °C in rice bread than in whole-wheat bread, which is consistent with starch retrogradation.     

利用大曲酒尾、酒糟发酵生产食醋的研究

以白酒生产的副产物大曲酒尾和酒糟为原料,采用黑曲霉、醋酸菌为发酵菌种,进行醋酸发酵生产食醋,经加工后可得优质食醋。本工艺不但解决了白酒厂酒糟污染问题,而且可获得较好的经济效益。     

Lignin Effect on Calcium Absorption in Rats

The effect of lignin on calcium absorption was studied in a rat model. Lignin preparations were isolated directly from wheat bran and from kale by two treatments, enzymatic and acidic. Calcium absorption in the presence or absence of isolated wheat bran lignin, isolated kale lignin, commercially available pine lignin, and wheat bran was determined by femur uptake of 45Ca. The fractional calcium absorption of wheat bran was significantly lower than for the control. However, there were no differences in calcium absorption between the various lignin sources and the control without lignin. Thus, lignin is probably not inhibitory to calcium absorption in plant foods.     

小麦麸皮戊聚糖氧化胶凝性质研究

分别采用过氧化氢与过氧化物酶(H2O2/POX),与葡萄糖、葡萄糖氧化酶与过氧化物酶(Glu/GOX/POX)酶氧化体系,以及(NH4)2S2O8、KBrO3化学氧化体系,研究小麦麸皮不同戊聚糖组分P-WSPI、P-WSPII、P-AEP Na、P-AEPca的氧化胶凝性质.研究发现,除P-WSPII组分不能发 生氧化交联反应外,在H2O2/POX、Glu/GOX/POX酶氧化体系以及(NH4)2S2O8化学氧化体系作用下,戊聚糖组分P-WSPII、P-AEPNa、P-AEPca均可不同程度地发生氧化交联反应.其中P-WSPI组分具有较好的氧化交联反应效果,其次是P-AEPca,以P-AEPNa组分的氧化交联反应效果较差.各戊聚糖组分在KBrO3化学氧化剂作用下,不能发生氧化交联反应.戊聚糖组分中阿魏酸含量的高低影响戊聚糖氧化交联反应的程度,即阿魏酸含量较高的戊聚糖组分具有较明显的氧化胶凝反应,阿魏酸含量较低的戊聚糖组分具有不太明显的氧化胶凝反应.     

生物预处理对机械制浆能耗及纸张性能的影响

本文综述了白腐菌（真菌的一种）预处理对机械制浆能耗及纸张强度和光学性能的影响，同时讨论了真菌种类、木材在、木片尺寸、生物处理添加物等因素的影响结果。