Ability of Selected Lactic Acid Bacteria to Ferment a Pearl Millet–Soybean Slurry to Produce Gruels for Complementary Foods for Young Children

Abstract: To assess the ability of lactic acid bacteria to improve some nutritional characteristics of the pearl millet–soybean slurry to prepare complementary foods for young children in African countries, inoculation was performed using strains previously selected for their ability to hydrolyse starch, phytate, or α-galactooligosaccharides (α-GOS). For the sake of comparison with the action of a natural microflora, fermentation was also performed by back slopping inoculation, that is, with a sample obtained from spontaneously fermented traditional pearl millet slurry obtained from a small scale processing unit in Burkina Faso (Ouagadougou). Starter cultures thrived on the slurry as shown by counts on MRS agar, TTGE fingerprints, and fermentation patterns. The fermentation of precooked slurries inoculated by back slopping or with mixed cultures containing the amylolytic strain Lb. plantarum A6 enabled partial starch hydrolysis. Corresponding gruels had a suitable consistency for young child feeding at high dry matter content, and a high energy density: 88.7 ± 4.2 and 75.8 ± 5.1 kcal/100 g of sweetened gruel, for the gruels inoculated by back slopping or with Lb. plantarum A6, respectively. Unexpectedly, no decrease in phytates was observed in any of the experiments, suggesting the presence of one or more inhibitory compounds in soybean. Furthermore, preprocessing conditions before fermentation affect the carbohydrate composition of slurry and have a more profound effect than fermentation on the reduction of the α-GOS content. Practical Application: This research aims to investigate the capacity of selected lactic acid bacteria to produce in a bioprocess high energy density and nutritious gruels for complementary feeding of young children from an African cereal (pearl millet) mixed with soybean.     

探讨定性检验麦芽糊精残留高温淀粉酶活性的三种方法

介绍了定性检验麦芽糊精成品中残留高温淀粉酶活性的三种方法：糖组分测试法、DE值测试法和黏度测试法。实验结果表明：通过测定麦芽糊精溶液95℃保温24h的糖组分、测定麦芽糊精溶液95℃保温8h的DE值或测定麦芽糊精与淀粉混合糊液50℃保温24h的黏度,都可以有效定性麦芽糊精产品是否残留高温淀粉酶活性,这三种测试方法可供麦芽糊精生产企业和用户选择。     

粳米配米机理的研究

为改善低质粳米食味品质,以不同品质粳米为原料,在分析大米和米饭的理化特性的基础上进行粳米配制技术的研究.结果表明:以一种米质较差、直链淀粉含量较高的粳米为主料,与米质较好、直链淀粉含量较低的辅料米按一定比例配制,能够改善低质米的综合品质.较高直链淀粉含量的大米与较低直链淀粉含量的大米混合,得到的米饭柔软,黏着性和咀嚼度好,食味值高,并且低直链淀粉米混合比例越高越好.     

果胶酶与高效淀粉酶液化澄清枸杞汁的效果对比研究

选用果胶酶和高效淀粉酶对枸杞汁进行澄清,在不同浓度、温度、pH和作用时间的条件下,比较了果胶酶和高效淀粉酶对枸杞汁澄清度及可溶性固形物含量的影响效果。结果表明:高效淀粉酶不具有良好的澄清效果,增加了枸杞汁的可溶性固形物含量;果胶酶的澄清效果优于高效淀粉酶,不增加枸杞汁的可溶性固形物含量,其最佳澄清工艺条件为:浓度0.004%,pH4.0,60℃,作用时间3h。     

Identification and antioxidative properties of transglycosylated puerarins synthesised by an archaeal maltogenic amylase

Puerarin is helpful for the prevention and treatment of various cardiovascular diseases. However, its insolubility often limits its uses. Transglycosylation reaction between 1% puerarin and 10% β-CD was catalysed by maltogenic amylase from archaeon Thermofilum pendens (TfMA) at 0.2 U/mg β-CD, 90 °C and pH 5.5, for 1 h in order to obtain puerarin glucosides of high water solubility. Seven puerarin derivatives with different number of additional α-glucosyl in the reaction solution were identified by HPLC–UV–MS analysis. Although less than puerarin, the transglycosylated puerarins still fully maintained their antioxidant activities, assessed by a radical scavenging test and a reducing power assay. Therefore, the transglycosylated puerarins exhibit a greater potential to be developed into new medicines and foods. This is the first report on the flavonoids glycosylation using the transglycosylation activity of archaeal maltogenic amylase.     

湿热处理对锥栗原淀粉及分离组分回生的影响

运用差示扫描量热分析仪研究了湿热处理对锥栗原淀粉、直链淀粉、中间成分和支链淀粉回生的影响。经湿热处理的锥栗原淀粉、支链淀粉在冷藏相同时间后的回生吸热峰起始温度(TO)、峰值温度(TP)、终止温度(TF)按湿热处理温度80、180、140和110℃递减,经湿热处理的锥栗直链淀粉在冷藏相同时间后的TO、TP、TF和吸热焓(ΔH)则按湿热处理温度80、180、110和140℃递减;经湿热处理的锥栗淀粉中间成分在冷藏相同时间后的TO、TP、TF和ΔH以80℃湿热处理时为最大,110、140和180℃湿热处理时的基本没有变化。经湿热处理的锥栗原淀粉、直链淀粉、中间成分和支链淀粉凝胶体系,在4℃冷藏前1周回生速度很快而后趋于平稳。     

A review of rapid microwave fixation technology: Its expanding niche in morphologic studies

Microwave (MW) fixation methods are important because excellent preservation of both cell structure and antigenicity can be attained several orders of magnitude faster than by routine chemical fixation methods. However, because of the limitations of commercial MW ovens, fixation results are often irreproducible. We present a standardization protocol for MW fixation in household MW ovens that emphasizes magnetron warm-up; the use of a water load during sample irradiation, of an agar/saline/Giemsa model to evaluate uniformity of irradiation within the MW cavity, and of specimen containers with one dimension less than 1.5 cm; and fast specimen handling to prevent conductive heating artifacts after irradiation. We describe a prototypic MW device that improves the precision of sample irradiation and fixes blocks of tissue and cells in suspension in milliseconds. The solutions used to immerse the specimen during irradiation influence the specimen morphology. Aldehyde- or osmium-containing solutions used simultaneously with MW irradiation resulted in the best morphologic preservation of specimens up to 1 cm³. Using MW fixation methods and a postembedding, ultrastructural immunogold-labeling approach, we have localized granule chymase and histamine in rat mast cells and amylase in rat parotid acinar cells.     

中温α-淀粉酶基因的克隆及在枯草芽孢杆菌中的高效表达

利用高效表达载体pWB980,实现了Bacillus subtilis BF7658中温α-淀粉酶基因amy在B．subtilis DB403中的高效表达,活力达到770U／mL．经多步纯化,重组酶AMY的比活达到35．8U／mg,纯化倍数为1．7,获得凝胶电泳条带单一的蛋白样品,经SDS—PAGE检测,重组酶AMY相对分子质量为4．8×10^4．对酶学性质进行分析,重组酶AMY的最适反应温度为60℃,最适反应pH为6．0．     

一株芝麻香型白酒高温大曲细菌Q2B1的鉴定及其产酶活性研究

大曲细菌关系到白酒酿造的品质,其中酶的含量与活性与白酒的风味紧密关联。以芝麻香型白酒高温大曲优势细菌代表菌株Q2B1为研究对象,利用分子生物学技术对其分类学地位进行研究,并通过全基因组研究技术对产酶相关功能基因与代谢通路进行研究。结果表明,菌株Q2B1被鉴定为贝莱斯芽孢杆菌（Bacillus velezensis）。利用传统的培养技术定性定量地检测其酶活力,发现菌株Q2B1可产淀粉酶和蛋白酶,活力分别为5.852 U/mL和26.770 U/mL;其产酶相关功能基因组长度为3 475 602 bp,包括蛋白酶编码基因以及淀粉酶编码基因,在基因水平上初步揭示了Q2B1菌株合成蛋白酶和淀粉酶的分子机理,为进一步合理开发白酒大曲微生物奠定理论基础,为提高白酒品质提供科学依据。     

Effects of boiling, warm-holding, mashing and cooling on the levels of enzyme-resistant potato starch

Summary The effects of boiling, warm-holding, cooling and mashing on the enzyme-resistant starch (ERS) content of potatoes was studied together with inter-tuber and inter-cultivar variation in ERS content. Inter-tuber variation in ERS content was small and mean values (on a dry matter basis) for boiled and raw potatoes were 10.7 and 74.2% (cultivar Rooster) and 10.8 and 74.3% (cultivar Anna). There was no significant difference between the ERS values of boiled potatoes of seven cultivars (range 10.0–10.8%). Warm-holding mashed potatoes at 65–70 °C for 1 hr raised ERS values from 2.20 to 4.80%. In a separate test slow cooling over 2 hr to 21 °C raised the ERS content from 3.65 to 6.35%. Multiple cook-cool (3×) gave ERS contents of 23.2 and 18.2% for boiled potatoes held for 24 hr at 4 or 20 °C. Mashing and freezing raised ERS values by 1–2%.