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木薯是发酵乙醇的主要原料之一,传统木薯酒精发酵过程中需要添加硫酸来抑制杂菌生长,过多添加硫酸容易腐蚀设备和污染环境,本研究以木薯为主要原料,通过添加酶制剂和乳酸链球菌素等抑制杂菌,木薯经粉碎后首先添加α-淀粉酶、糖化酶进行液化和糖化,然后添加果胶酶、纤维素酶和乳酸链球菌素进行发酵。通过单因素试验和正交试验,优化发酵复合酶制剂添加量,当果胶酶添加量为140 U/g,纤维素酶添加量为8 U/g,乳酸链球菌素添加量为0.5%时,木薯发酵酒精的酒精度为16.2%,明显高于不添加或添加单种酶制剂的酒精度,复合酶制剂可以有效提高木薯发酵酒精浓度。 相似文献
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为实现木薯酒精发酵中原材料利用的降本增效,该研究将木薯作为原料进行酒精发酵条件实验,确定液化温度为95.0℃时,液化时间为70.0 min;糖化温度为60.0℃时,糖化时间为40.0 min;在上述条件下木薯淀粉最高产酒率为54.01%,淀粉的利用率达89.25%。在此基础上,研究了酶制剂废液(包括糖化酶废液、淀粉酶废液)应用于木薯酒精生产。结果表明,添加糖化酶废液后,每吨酒精可以节省淀粉酶1320 mL,糖化酶316.8 mL,同时可免去尿素、硫酸镁等营养盐的添加,出酒率提高至54.64%。因此,采用酶制剂废液可大大减少木薯酒精生产中新鲜糖化酶和淀粉酶的用量,降低了营养盐的添加,同时原料出酒率也得到了有效提高。本研究不仅为酶制剂工业生产中酶制剂废弃资源的有效利用提供了新途径,也为木薯酒精发酵工业发展提供了新的理论支持。 相似文献
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木薯渣分批补料酶水解及酒精发酵的研究 总被引:2,自引:0,他引:2
木薯渣是木薯淀粉加工后的废弃物,碳水化合物含量高。实验利用复合酶对木薯渣中淀粉和纤维素等碳水化合物非热水解进行了探索,结果表明:木薯渣具有较好的酶解性能;随着底物浓度的增大,酶解液糖浓度也不断提高,酶解得率逐渐降低;与间歇糖化工艺相比,16%底物在相同的水解条件和相同的酶添加量的条件下,采用4%的起始底物浓度,每隔12 h进行补料,葡萄糖得率从53.6%提高到72.4%;以不添加任何营养物质的水解液为原料进行酒精发酵,24h乙醇浓度达到24.9 g/L,乙醇得率达到42%,发酵效率为82%,乙醇产率达到1.04 g/(L.h),葡萄糖利用率达到97%。 相似文献
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介绍了利用新鲜木薯生产乙醇的新工艺:用真菌α淀粉酶和降粘酶预处理新鲜木薯醪液,后加入颗粒淀粉水解酶STARGENTM进行酵母酒精发酵.该工艺可直接利用新鲜木薯进行酒精发酵;相比传统高温工艺,该发酵新工艺过程中新鲜木薯醪液粘度显著降低,有更多可发酵性糖被利用,并且最终发酵效率显著提高. 相似文献
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Paulinus N Okolie Emmanuel N Ugochukwu 《Journal of the science of food and agriculture》1988,44(1):51-61
The cell wall degrading enzymes polygalacturonase (EC 3.2.1.15),pectinase (EC 3.1.1.11), cellulose (EC 3.2.1.4) and xylanase (EC 3.2.1.8), as well as α-amylase (EC 3.2.1.1) and phosphorylase (EC 2.4.1.1), were monitored during fermentation of cassava (Manihot esculenta Crantz) with Citrobacter freundii. All the enzymes were detected in cassava at the start. During fermentation, initial decreases in polygalacturonase, cellulase and xylanase were followed by increases which peaked as the tissue softened. There were significant (P<0.05) increases in pectinase, xylanase, cellulase, polygalacturonase and phosphorylase in inoculated cassava and the fermentation medium relative to controls (uninoculated cassava and medium) during the softening period. The control cassava did not ferment, indicating that the textural changes in inoculated cassava were due to enzymes secreted by C freundii. Studies on the effect of enzyme inhibition on fermentation showed that the pectic enzymes and cellulase were of primary importance and that inhibition of α-amylase and phosphorylase had no effect on the process. 相似文献
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以新鲜甜木薯为原料,跟踪监测木薯酒发酵过程中的理化指标,并采用高效液相色谱法分析木薯酒发酵期间的有机酸组成及动态变化情况,进一步分析酒发酵过程中的酸味强度。结果表明,发酵过程中,木薯酒中的还原糖含量先快速上升至最高点最后趋于平稳(54.67 mg/mL);酒精度先上升后平稳(7.11%vol);总酸含量先缓慢减少至2.21 mg/mL,再缓慢增加,后快速增加,与pH值变化趋势相反。酒石酸、乳酸、乙酸、柠檬酸、琥珀酸是木薯酒发酵中重要有机酸,分别占木薯酒总有机酸含量的2.66%~12.31%,41.50%~63.53%,18.21%~23.82%,1.22%~27.77%,3.17%~15.89%,其他有机酸是酒中的辅助酸味特征成分。乳酸和乙酸是木薯酒的主体酸,其味道强度值(TAV)占总TAV值的65.82%~95.84%,发酵84 h的木薯酒有最高的味道强度值,其可达到223.87。 相似文献
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Huch Née Kostinek M Hanak A Specht I Dortu CM Thonart P Mbugua S Holzapfel WH Hertel C Franz CM 《International journal of food microbiology》2008,128(2):258-267
Two Lactobacillus strains, Lactobacillus plantarum BFE 6710 and Lactobacillus fermentum BFE 6620, were used to start cassava fermentations in a pilot study under field production conditions in Kenya, to determine their potential to establish themselves as predominant lactobacilli during the fermentation. Predominant strains from three fermentations were isolated throughout the 48 h fermentation period. The use of these strains in high numbers clearly resulted in 1 to 2 log higher lactic acid bacteria (LAB) counts over the course of the fermentation when compared to the uninoculated control. 178 predominant LAB isolates were grouped based on their phenotypic characteristics, and were characterised to strain level by RAPD-PCR, followed by PFGE strain typing. Overall, L. plantarum strains represented the majority of the isolates, followed by Weissella confusa and Lactococcus garvieae strains. The results of RAPD-PCR and PFGE strain typing techniques indicated that L. plantarum BFE 6710 was successful in asserting itself as a predominant strain. In contrast, L. fermentum BFE 6620 failed to establish itself as a predominant organism in the fermentation. The success of the L. plantarum strains to predominate in the cassava fermentation demonstrates the potential for development of Lactobacillus starter cultures to industrialise the Gari production process. 相似文献
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The use of a starter culture in the fermentation of cassava for the production of "kivunde", a traditional Tanzanian food product 总被引:2,自引:0,他引:2
Kimaryo VM Massawe GA Olasupo NA Holzapfel WH 《International journal of food microbiology》2000,56(2-3):179-190
Three cassava fermentation methods (spontaneous fermentation, back-slopping and the use of starter culture) for the production of kivunde, executed in three trials at 30 degrees C, were compared in terms of cyanide level reduction, microbiology and product quality improvement. Among the isolates from spontaneously fermented cassava batches, four strains were selected on the basis of their enzymatic activities and acid production. All were identified as Lactobacillus plantarum and were used as starters in this study. Lowest residual cyanide levels were detected after 120 h fermentation time in samples fermented with the starter culture and were below the maximum value of 10 mg/kg recommended by the Codex/FAO for cassava flour. This finding seems to be related to the alpha-glucosidase activity of the inoculated strains of which API-zyme (Bio-Merieux) tests showed activities of between 20 and > or = 40 nmol/4 h. The total residual cyanide levels of the spontaneous and back-slopping fermentations at 96 h were respectively 43.5 and 47.7 mg/kg dry weight of cassava. Extension of the fermentation period to 5 days, lead to further substantial reduction in the residual cyanide level in both these processes, but not below the recommended maximum value as in the case of starter culture fermented products. The spontaneous and back-slopping fermented cassava showed signs of deterioration after 3 days of fermentation. There was a sharp drop of pH and an increase of titratable acidity for all three batches during the first 48 h followed by a slow rise of pH and drop in titratable acidity towards the end of fermentation. The samples fermented with the starter culture had a smooth texture and pleasant fruity aroma, as opposed to the course and dull appearance and more complex flavour of the samples of spontaneous and back-slopping batches. During fermentation with starter culture, Enterobacteriaceae and yeasts and moulds could not be isolated throughout the period of fermentation (detection limit: 10 colony forming units/g). The present findings indicate the suitability of these Lb. plantarum strains as starter cultures for cassava fermentation in the kivunde process. The paper highlights the potential for the improvement of a traditional African fermented food (kivunde) through the use of a starter culture. 相似文献
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以木薯水解液作为发酵培养基基质,通过木葡萄糖酸醋杆菌(Komagataeibacter xylinus)发酵制备细菌纤维素(BC),利用单因素实验研究了温度、装液量、初始pH、木薯水解液添加量、接种量等对细菌纤维素产量的影响,并对发酵过程中的细菌纤维素产量、还原糖消耗量、pH、细菌纤维素含水率与复水率等指标进行了检测,采用元素分析、红外光谱分析、热重分析、扫描电镜、X射线晶体衍射(XRD)等对发酵得到的细菌纤维素进行表征。结果表明,木薯水解液发酵生产细菌纤维素的最优条件为:温度30℃、装液量75 mL、初始pH6.0、木薯水解液添加量3%、接种量6%;在细菌纤维素发酵过程中,pH从5.51下降到2.66,还原糖含量从32.1 g/L降到10.2 g/L,发酵9 d可得到5.75 g/L的细菌纤维素;所得细菌纤维素的含水率为96%~98%,复水率为50%~58%;元素分析结果表明细菌纤维素主要由C、H、O三种元素构成,符合纤维素中各元素含量;红外光谱揭示了细菌纤维素的特征吸收峰;热重分析表明细菌纤维素在290℃处具有最大失重,失重率达32.33%;扫描电镜观察到细菌纤维素的直径在100~500 nm之间;XRD分析得到细菌纤维素的结晶度为93.4%。因此木薯水解液是可以替代葡萄糖作为发酵生产细菌纤维素的碳源。 相似文献
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Golden Nka Odey Won Young Lee 《International Journal of Food Science & Technology》2020,55(2):813-822
The study investigated the effect of fermentation of cassava roots on the quality characteristics of flour and pasta. Cassava roots were fermented under natural condition for a period of 12, 36 and 60 h. Physicochemical properties, microbial analysis, pasting properties, in vitro digestibility, X-ray diffraction analysis of cassava flour, cooking properties, texture profile analysis (TPA) and sensory properties of the pasta were examined. The moisture content, carbohydrate, water absorption capacity, swelling and solubility index of fermented flour increased with an increase in fermentation period. Also, as fermentation progressed, increase in pasting viscosities of cassava flour was observed. The resistant starch (RS) content of cassava flour decreased with increasing period of fermentation. The duration of fermentation process significantly affected textural properties and cooking loss of cassava pasta. Sensory assessment showed that cassava roots fermented for 36 h gave pasta with the most acceptable qualities. 相似文献