不同发酵基质对红曲重要代谢产物的影响

功能红曲由于含有包括Monacolin K、伽马-氨基丁酸、色素等诸多生物活性成分而逐渐成为受人欢迎的功能性食品.但是,红曲产品中桔霉素的污染限制了红曲相关企业的健康发展.本实验考察了不同培养基质对红曲发酵产品重要代谢产物的影响.检测的内容包括:Monacolin K、伽马-氨基丁酸、色价以及桔霉素.结果显示大米复配麦麸较单纯使用大米为发酵基质的红曲产品其Monacolin K的含量增加了1倍.大米复配豆粕为发酵基质有效地消除了桔霉素的污染.     

红曲发酵加工工艺及桔霉素控制研究进展

红曲是红曲霉以大米为基质发酵而来的产品,富含红曲色素、monacolin K(MK)和γ-氨基丁酸等功能性代谢产物。桔霉素是红曲霉在代谢过程中所产生的一种真菌毒素,摄入桔霉素可对肾脏、肝脏、心脏和生殖系统产生毒性作用。本文对红曲发酵技术、桔霉素检测技术及控制技术等方面进行阐述,分析当前红曲发酵生产尚存的不足之处,并对红曲霉未来研究方向及红曲工业前景作出展望,以期为红曲生产提供参考。     

以合成桔霉素的关键基因为靶标的PCR检测方法与UPLC法检测红曲中桔霉素含量的一致性分析

为了解菌株中桔霉素生物合成基因与其发酵产品红曲中桔霉素含量的相关性,本实验以25株不同来源的红曲菌为研究对象,以桔霉素合成的关键基因为标靶,设计6对引物进行PCR扩增;同时采用传统生产工艺制备红曲,采用免疫亲和柱纯化与UPLC结合的方法测定红曲中桔霉素的含量。对比PCR扩增结果与UPLC检测结果表明,PCR方法得到的结果与UPLC检测结果具有高度一致性,即PCR扩增桔霉素合成关键基因为阳性的菌株,其发酵制备的红曲中桔霉素含量超过了QB/T 2847-2007功能性红曲米(粉)的桔霉素限量标准50 μg/kg,而PCR结果中桔霉素合成关键基因为阴性的,桔霉素含量均低于仪器检测限15.92 μg/kg,远低于QB/T 2847-2007功能性红曲米(粉)的桔霉素限量标准。结果表明,本研究采用的PCR方法可以作为判断传统工艺条件下生产的红曲产品中桔霉素是否超标的依据,也为了解菌株分泌桔霉素的能力提供了基本信息。     

8株红曲菌生产特性研究

采用固态和液态两种发酵方法对8株野生红曲菌进行发酵,分析对比其产色素能力、产生理活性物质莫纳可林(Monacolin K)能力及产桔霉素情况,以筛选出可在发酵食品工业上安全应用的优良红曲菌菌株。结果表明:8株红曲菌生产特性存在显著性差异,其中L2菌株红曲色素产量和Monacolin K产量最高,而真菌毒素桔霉素产量最低,是一株可安全应用于发酵食品工业的优良菌株。     

烘干和辐照对功能性红曲Monacolin K含量的影响

针对功能性红曲生产过程中的烘干及辐照两道工序对功能性红曲中Monacolin K含量的影响因素进行了研究.发现烘干温度越高,酸式结构的Monacolin K越多地脱水转化成内酯式结构的Monacolin K,在100℃下烘干15 h,总Monacolin K含量从7 748.01 mg/kg下降到5 663.92mg/kg,下降幅度26.9%左右.烘干时间对Monacolin K的降低及酸式Monacolin K的比例也有明显的影响.功能性红曲产品经钴-60辐照后总Monacolin K含量下降10%以上,酸式结构和内酯式结构的Monacolin K的含量均下降,酸式结构下降的幅度比内酯式结构下降的幅度更大.     

红曲霉菌的研究进展

该文重点阐述了3个问题红曲固态培养技术、液态培养技术及利用基因工程技术改造红曲霉菌种,提高功能性红曲中莫纳可林K及降低红曲产品中桔霉素含量.提出了应在红曲行业引入GMP和HACCP的管理体系;并就红曲米工厂的现状提出了一些建议.     

辐照对红曲米中桔霉素及Monacolin K含量的影响

利用1~20 kGy 6种不同~(60)Co辐照剂量处理红曲米及其提取液,采用高效液相色谱法(HPLC)检测样品中桔霉素(Citrinin)和Monacolin K含量,比较不同辐照剂量下固体红曲米及其提取物的差异。试验结果表明:经辐照强度为20 kGy辐照处理后,固体红曲米中桔霉素的含量减少了43%,Monacolin K及其类似物总含量减少了5%。在辐照强度超过5 kGy时红曲米提取液中桔霉素全部降解;辐照强度超过10 kGy提取液中的Monacolin K及其类似物完全降解。在辐照条件下Monacolin K的稳定性好于桔霉素,因此辐照处理可以在Monacolin K较少降解的条件下有效除去红曲米中的桔霉素。     

低产桔霉素红曲霉菌种的选育研究

从16株红曲霉菌种中筛选出HS—9作为诱变育种的出发菌株，选育出的HS—9-125的桔霉素、Monacolin K和色价含量分别为0．65mg／kg、4．855mg／g和3580U／g，该红曲霉菌株可望用于高Monacolin K、高色价红曲的安全生产。     

两种红曲菌固态发酵产莫纳可林K和桔霉素的比较

红曲菌可产生具有降血脂功能的莫纳可林K,但部分菌株产生的桔霉素引起了人们对红曲产品安全性的担忧。选取11株紫色红曲菌和10株红色红曲菌,通过高效液相色谱法分析各菌株固态发酵所产红曲米中莫纳可林K和桔霉素的含量。结果表明,11株紫色红曲菌和4株红色红曲菌可产生桔霉素,1株紫色红曲菌和9株红色红曲菌可产生莫纳可林K。其中5株红色红曲菌所生产的红曲中莫纳可林K和桔霉素含量符合QB/T 2847—2007《功能性红曲(米粉)》。该结果可为修改红曲产品相关标准提供有价值的信息。     

功能性红曲中功能成分的研究进展

为了更好地利用红曲,介绍了红曲中红曲色素、洛伐他汀和桔霉素等的组成、提取与检测方法,同时还介绍了桔霉素的降解方法,并综述红曲中其它功能成分有麦角甾醇、酶类活性物质和γ-氨基丁酸等,同时,对功能性红曲潜在的价值空间做出了展望.     

高产开环型monacolin K红曲霉菌株的筛选及其在红曲酒酿造中的应用

该研究采用38株红曲霉菌株固态发酵制备功能红曲米,采用高效液相色谱法测定红曲米中monacolin K和桔霉素含量,筛选高产开环型莫纳可林K(monacolin K)红曲霉菌株,通过形态观察及分子生物学技术对筛选菌株进行鉴定,并将其应用于红曲酒酿造,分析红曲酒的品质。结果表明,筛选得到1株高产开环型monacolin K、不产桔霉素的菌株ABQ2,经鉴定,其为丛毛红曲霉（Monascus pilosus）。采用该菌株发酵制备功能红曲米中的monacolin K含量达到25.10 mg/g,开环率为90.5%,且桔霉素未检出。采用菌株ABQ2酿造的红曲酒酒精度为12%vol,酸度为1.91 g/100 mL,monacolin K含量为0.48 mg/mL,其理化指标均符合相关行标要求;与小曲酒相比,红曲酒中总酯含量（433.65 mg/L）极显著增加（P<0.01）,其中乳酸乙酯和乙酸乙酯含量最高,高级醇类含量（145.52 mg/L）略低,主要为正丙醇、异丁醇、正戊醇、β-苯乙醇等。     

Degradation kinetics of monacolin K in red yeast rice powder using multiresponse modeling approach

The effects of storage temperature (4, 20, 30, 40, 50 °C) and atmospheric conditions in packages (vacuum, atmospheric) on degradation kinetics of monacolin K, an antihypercholesterolemic agent, in red yeast rice powder were investigated using multiresponse modeling approach. Storage of red yeast rice powder at 4 °C under vacuum package was found to enhance retention of monacolin K. Multiresponse modeling revealed degradation path of monacolin K acid form into their dehydromonacolin K and unknown product under vacuum package, while oxidized product was also formed under atmospheric package. Monacolin K lactone form and precursor were degraded into dehydromonacolin K lactone form, while degradation of dehydromonacolin K lactone form to unknown was more pronounced at temperature higher than 30 °C. Oxidized product was also generated from monacolin K lactone form in atmospheric package. High activation energy of monacolin K degradation in acid form indicated that degradation of monacolin K to their dehydromonacolin K was more susceptible to temperature change as compared to lactone form.     

Optimization of Extraction Conditions of Citrinin from Red Yeast Rice by Orthogonal Design and Quantification of Citrinin by High-Performance Liquid Chromatography

An orthogonal experimental design was utilized to optimize extraction condition of mycotoxin citrinin from red yeast rice. The results showed that the combination of the following conditions was the optimum extraction condition: 50 % ethanol as extraction solvent, 1:5 as the solid-to-liquid ratio, and vortex for 5 min followed by 20 min ultrasonication as extraction manner. Under the optimum extraction condition, citrinin in 11 commercial red yeast rice products was extracted and quantified by optimized high-performance liquid chromatography (HPLC) conditions which consisted of acetonitrile and acidic water (pH 2.5) as mobile phase, flow rate of 1 mL/min, and fluorescence detector. The quantification results showed that seven products contained citrinin; the highest content of citrinin was 57.28 μg/g. The citrinin contamination rate in collected red yeast rice samples was 63.6 %. This investigation indicates that the optimized extraction method followed by HPLC fluorescence detection is a sensitive and effective method to quantify citrinin. The results also indicate that most red yeast rice products in China contain citrinin. However, there are no national criteria about citrinin limit in red yeast rice and the related products. Therefore, a national regulation standard in terms of quantification method should be set up to limit citrinin contamination and to control the circulation of red yeast rice products in China.     

Preparation of Monascus-fermented ginkgo seeds: optimization of fermentation parameters and evaluation of bioactivity

Food Science and Biotechnology - In this study, a high monacolin K yield was achieved through solid-state fermentation of Ginkgo biloba seeds. Monascus purpureus suspension made from red yeast rice...     

pH精制区带逆流色谱分离制备红曲中的酸式莫那可林K

建立了pH精制区带逆流色谱分离制备红曲中功能成分酸式莫那可林K的新方法。首先用体积分数95%乙醇提取红曲中的莫纳可林K,然后经过碱化处理使内酯式莫那可林K转化为酸式,最后采用溶剂系统V(石油醚):V(乙酸乙酯):V(甲醇):V(水)=5:5:4:6,上相添加HCl(10mmol/L)作为固定相,下相添加氨水(10mmol/L)为流动相进行pH精制区带逆流色谱分离。分离所得的酸式莫那可林K经HPLC检测纯度,并用UV,ESI-MS和~1H-NMR鉴定其化学结构。从2.0g粗提物一次分离得到纯度为93.4%的酸式莫那可林K147mg。     

Characteristics of Monascus sp. isolated from Monascus fermentation products

To screen for the strains suitable for industrial applications, 15 Monacus sp. were isolated from various Monascus fermentation products. The isolated strains were belonging to Monascus pilosus, Monascus purpureus, Monascus albidulus, and Monascus femeus based on the ITS sequence and morphological characteristics. They produced globular and hyaline conidia, and red, orange, or hyaline ascomata except for M. fumeus, in which ascomata was not observed in malt extract media. Each strain produced monacolin K and citrinin at different levels on different media: 15.79–20.05 mg/L of monacolin K and 0–255 μg/L of citrinin in submerged culture of monacolin K producing media, 1.27–2.69 mg/L and about 507.4 μg/L in YES medium, 0–0.78 g/kg and 0–9.7 mg/kg in Monascus red rice products, suggesting that it is necessary to adopt the similar conditions to a specific application for screening as well. These various isolated strains would be great resources for industrial application to develop Monascus fermented functional products.     

Study on red fermented rice with high concentration of monacolin K and low concentration of citrinin

Red fermented rice (RFR), known as Asian traditional fermentation foodstuff, is now used as natural colorants and a dietary supplement all over the world. However, the discovery of citrinin in RFR has led to a controversy about the safety of RFR. In this paper, a mutant strain, Monascus spp. M12-69, was acquired by treatment with mutagenic agents from a wild strain M12 of Monascus screened from RFR samples gathered around China. According to the classification guide of Hawksworth and Pitt on Monascus genus, they belong to Monascus pilosus Sato. The conditions of solid state fermentation of M12-69 were optimized. At the optimum conditions, the concentrations of monacolin K and citrinin in RFR, which was dried at 50 degrees C to a constant weight, were 2.52 mg/g and 0.13 ng/g, respectively. These results reveal that Strain M12-69 is a potential strain, which can be used to produce RFR with high concentration of monacolin K and low concentration of citrinin.     

5种金属离子对紫色红曲霉主要次生代谢物谱的调节作用

目的:研究金属离子对紫色红曲霉生长和主要次生代谢物合成的调节作用。方法:将紫色红曲霉孢子接种到含不同浓度的金属离子（Cu2+、Zn2+、Mg2+、Mn2+、Co2+）的固体培养基,观察不同离子对其生长和色素合成的影响;同时,将不同浓度的上述离子及金属螯合剂8-羟基喹啉分别接种到液体培养基中,测定紫色红曲霉生物量、红曲色素、莫纳克林K、γ-氨基丁酸和桔霉素等主要次生代谢物含量及发酵液中代谢物谱变化。结果:Cu2+（0.5 mmol/L）处理导致水溶红、橙、黄色素产量分别提升了2.01、2.07和1.73倍;醇溶色素分别增加了2.83、1.74和1.95倍;莫纳克林K和桔霉素分别增加了1.78和5.53倍。Zn2+（0.5 mmol/L）促使水溶、醇溶色素分别增加了93.3%、78.6%、57.6%和2.9、1.54、0.54倍。莫纳克林K和桔霉素则分别增加了0.92和6.91倍。0.5 mmol/L的Mg2+处理导致生物量有所下降,但无显著差异;水溶、醇溶色素则分别增加了2.68、2.25、2.02倍和1.26、1.23、1.82倍;莫纳克林K则增加了51.8%。0.25 mmol/L的Mg2+则使桔霉素提升了1.79倍。Mn2+（0.5 mmol/L）刺激水溶、醇溶色素产量分别增加了48.3%、29.9%、24.8%和131.1%、83.6%、49.2%,莫纳克林K增加了1.01倍。而桔霉素则在1 mmol/L Mn2+刺激下增加了92.3%。Co2+（0.5、1 mmol/L）导致生物量分别降低了47.9%和53.7%,而醇溶色素则分别提高了4.07、5.04、2.62倍和3.07、3.41、2.70倍,对莫纳克林K合成无作用;桔霉素产量分别降低了90.8%和93.9%。上述离子均不利于γ-氨基丁酸的合成。金属离子螯合剂8-羟基喹啉（20 μmol/L）使红曲霉生物量降低了26.9%,水溶色素分别下降了40.6%、34.3%和26%。莫纳克林K和桔霉素分别降低了56.7%和90.1%。发酵液的波谱（200~600 nm）扫描结果发现,金属离子仅调节代谢物的产量,并不改变紫色红曲霉代谢物种类。结论:金属离子不仅影响紫色红曲霉的生长,并显著调节其主要次生代谢物谱。     

十种添加物对红曲菌monacolin K产量的促进效果分析

为了提高红曲菌液态发酵产monacolin K的能力,本文对紫色红曲菌(Monascus Purpureus)M1进行培养基成分优化从而提高monacolin K产量。在实验室原培养基成分中添加山药粉、桔皮粉、酵母菌液、酵母上清液、酵母破壁液、破壁后的酵母菌液、亮氨酸、谷氨酸、乙醇等物质,对不同培养基中红曲菌的次级代谢产物产量进行测定。结果表明:添加谷氨酸可以极显著(p<0.01)提高monacolin K产量,提高了5.60倍;添加山药粉、酵母菌液、酵母上清液、酵母破壁液、破壁后的酵母菌液能提高红曲红和红曲黄色素的色价,其中添加酵母菌液对红曲红色素提高效果极显著(p<0.01),提高51.4%;通过扫描电镜检测谷氨酸培养基和普通培养基中红曲菌菌丝体的差异发现添加了谷氨酸的菌丝体更膨大,其细胞壁与原生质体之间缝隙增大,推测其细胞膜的通透性增加,进而导致细胞内积累的monacolin K能转移到胞外,使发酵液中monacolin K产量提高。