Structure and immunomodulatory activity of Lentinus edodes polysaccharides modified by probiotic fermentation

Plant-based fermentations provide an untapped source for novel biotechnological applications.In this study,a probiotic named Lactobacillus fermentum 21828 was introduced to ferment Lentinus edodes.Polysaccharides were extracted from fermented and non-fermented L.edodes and purified via DEAE-52 and Sephadex G-100.The components designated F-LEP-2a and NF-LEP-2a were analyzed by FT-IR,HPGPC,HPAEC,SEM,GC-MS and NMR.The results revealed that probiotic fermentation increased the molecular weight from 1.16×10^(4) Da to 1.87×10^(4) Da and altered the proportions of glucose,galactose and mannose,in which glucose increased from 45.94%to 48.16%.Methylation analysis and NMR spectra indicated that F-LEP-2a and NF-LEP-2a had similar linkage patterns.Furthermore,their immunomodulatory activities were evaluated with immunosuppressive mice.NF-LEP and F-LEP improved immune organ indices,immunoglobulin(Ig G and Ig M)and cytokines concentrations;restored the antioxidation capacity of liver;and maintained the balance of gut microbiota.F-LEP displayed better moderating effects on the spleen index,immunoglobulin,cytokines and the diversity of gut microbiota than NF-LEP(200,400 mg/kg).Our study provides an efficient and environment-friendly way for the structural modification of polysaccharides,which helps to enhance their biological activity and promote their wide application in food,medicine and other fields.

Fermented Lentinus edodes extract containingα-glucan ameliorates concanavalin A-induced autoimmune hepatitis in mice

Autoimmune hepatitis(AIH)is a chronic inflammatory liver disease that threatens human health worldwide.The aim of this study was to detect the protective effect of a fermented Lentinus edodes extract containingα-glucan(FLA),in a concanavalin A(Con A)-induced AIH mouse model and to determine the underlying liver-protective mechanism.The results showed that compared with the model group,the level of proinflammatory cytokines in serum of FLA pretreated mice was significantly decreased,and the degree of inflammatory cell infiltration in liver,thymus and spleen was significantly reduced.Quantitative polymerase chain reaction,immunohistochemistry,and Western blotting showed that FLA pre-treatment inhibited the Con A-induced apoptosis of hepatocytes by down-regulating the expression of BAX and up-regulating the expression of BCL-2.Further research found that FLA may improve liver injury in mice by activating NRF2 signaling pathway and inhibiting TRAF6/NF-κB signaling pathway.Thus,FLA may improve liver injury in mice by shifting gut microbial composition to reduce the release of inflammatory cytokines in the serum and prevent the necrosis of hepatocytes.Up-regulation of NRF2 signaling pathway,down-regulation of TRAF6/NF-κB signaling pathway,and an increase in the relative abundance of Lactobacillus_johnsonii and Ligilactobacillus_murinus play a protective role in liver.

PEG-mediated Transformation of Lentinus edodes

Expression vector p301-bG1 contains a Sw gene and a bialaphos resistance gene both driven by glyceraldehydes-3-phosphate dehydrogenase (GPD) gene promoter isolated from Lentinus edodes ( Berk.) Sing. Using p301-bG1, PEG-mediated transformation of protoplast of L. edodes was studied. Mixed with PEG-purified plasmid DNA, the protoplasts of L. edodes were treated with PEG solution and cultured on CYM regeneration plate containing 40 mug/mL bialaphos. Bialaphos-resistant and GUS-positive transformants were obtained using this transformation system. Although the transformation efficiency was relatively low, the protocols release large expenses on expensive instrument and restriction enzymes, providing a simple and economical method for mushroom breeding at the molecular level.

香菇(Lentinus edodes)对重金属镉(Cd)的吸收规律及控制技术研究

通过在香菇培养料中投放一定浓度的重金属镉(Cd),研究香菇子实体对Cd的吸收富集规律。结果表明,香菇子实体对培养料中Cd的吸收富集规律为y=541.77x2.938(2R2=0.9135)(x、y分别为培养料、香菇中Cd的含量),富集系数达到10.39～18.00,当香菇子实体中Cd的含量为y=1.5mg·kg-1时,培养料中Cd的临界含量值x=0.1347mg·kg-1。分别选择3个香菇主栽品种、两种不同栽培方式进行比较试验,研究香菇对Cd的积累特性。结果表明,Cd低富集的品种为"庆元9015",比对镉积累最多的"庆科20"Cd含量降低33.19%,Cd低富集的栽培方式为"离地层架栽培方式"。据此形成了香菇中重金属Cd的综合控防技术,为香菇质量安全控制提供依据。

固定香菇(Lentinus edodes)菌柄废弃物吸附Cd和Pb后的解吸试验研究

利用6种不同的解吸剂对吸附了Pb^(2+)和Cd^(2+)的固定香菇小球进行解吸。结果表明,HCl溶液做解吸剂最佳,可以分别在90 min和60 min内将大量的Pb^(2+)和Cd^(2+)从聚乙烯醇-海藻酸钠(PVA-SA)固定香菇小球上解吸出来。利用模拟二级动力学方程描述HCl溶液对PVA-SA固定香菇小球上Pb^(2+)和Cd^(2+)的解吸过程,决定系数R^2分别为0.996 9和0.998 9。Cd^(2+)的解吸率在HCl浓度为0.1 mol·L^(-1)时达到平衡,解吸率为80%;Pb^(2+)的解吸率在HCl浓度为1.0 mol·L^(-1)时达到最大,为99.01%。微观形态研究表明,未吸附重金属的PVA-SA固定香菇小球表面粗糙多孔,小球通过物理性吸附或形成无机沉淀将重金属沉积在细胞壁上后,表面变得密实。经HCl解吸后的PVA-SA固定香菇小球表面粗糙度和孔隙度都恢复到吸附前的状态。PVA-SA固定香菇小球对Pb^(2+)和Cd^(2+)进行吸附后,利用HCl进行解吸,再吸附,如此3次循环使用后,其吸附率略有降低,但仍可达到85.24%和69.07%。

Mathematical Modeling and Effect of Various Hot-Air Drying on Mushroom(Lentinus edodes)

An experimental study was performed to determine the characteristics and drying process of mushroom （Lentinus edodes） by 6 different hot-air drying methods namely isothermal drying, uniform raise drying, non-uniform raise drying, uniform intermittent drying, non-uniform intermittent drying and combined drying. The chemical composition （dry matter, ash, crude protein, crude fat, total sugars, dietary fiber, and energy）, color parameters （L, a＊, b＊, c＊, and h~） and rehydration capacities were determined. Among all the experiments, non-uniform intermittent drying reached a better comprehensive results due to the higher chemical composition, better color quality associated with high bright （26.381＋5.842）, high color tone （73.670＋2.975）, low chroma （13.349a：3.456） as well as the highest rehydration （453.76% weigh of dried body）. Nine kinds of classical mathematical model were used to obtained moisture data and the Midili-kucuk model can be described by the drying process with the coefficient （R2 ranged from 0.99790 to 0.99967）, chi-square （X2 ranged from 0.00003 to 0.00019） and root mean square error （RMSE ranged from 0.000486 to 0.0012367）.

STRUCTURE,MOLECULAR WEIGHT AND BIOACTIVITIES OF(1→3)-β-D-GLUCANS AND ITS SULFATED DERIVATIVES FROM FOUR KINDS OF LENTINUS EDODES

Lentinan samples,(1→3)-β-D-glucans containing 4.6-15.2 wt% proteins,coded as L-I_1 L-I_2 L-I_3 and L-I_4(L-I)were isolated from four kinds of Lentinus edodes.These glucans were treated with acetone to remove the protein in orderto obtain free protein glucans coded as LNP-I_1,LNP-I_2.LNP-I_3 and LNP-I_4(LNP-I).The free-protein polysaccharideswere sulfated to give derivatives(S-LNP-I)with degree of substitution(DS)from 0.4-0.8.The structural features andweight-average molecular weight(M_w)of the samples were investigated by using infrared spectroscopy,elemental analysis,^(13)C-NMR,size exclusion chromatography combined with laser light scattering(SEC-LLS)and viscometry.The effects ofstructure and conformation of the polysaccharides on antitumor activities were assayed in vivo(Sarcoma 180 solid tumors)and in vitro(Sarcoma 180,HL-60,MCF-7 and Vero tumors).The results indicated that the predominant species of thesamples L-I and LNP-I in 0.2 mol/L NaCl aqueous solution existed as triple-helical chains with high rigidity and in dimethylsulfoxide(DMSO)as single-flexible chains.Interestingly,the antitumor activities of LNP-I are lower than those of the nativeglucans(L-I),whereas their sulfated derivatives have higher inhibition ratio against Sarcoma 180 than LNP-I.The resultsreveal that the binding of protein,sulfated modification and the triple helix conformation are important factors in theenhancement of the antitumor activities of polysaccharides on the whole.

CRITICAL CONCENTRATIONS OF α(1→3)-D-GLUCAN FROM LENTINUS EDODES IN NaOH AQUEOUS SOLUTION

Critical concentrations of α-(1→3)-D-glucan L-FV-Ⅱ from Lentinus edodes were studied by viscometry andfluorescence probe techniques. The dependence of the reduced viscosity on concentration of the glucan in 0.5 mol/L NaOHaqueous solutions with or without urea showed two turning points corresponding to the dynamic contact concentration c_s andthe overlap concentration c~* of the polymer. The values of c_s and c~* were found to be 1×10^(-3) g cm^(-3) and 1.1×10^(-2) g cm^(-3),respectively, for L-FV-Ⅱ in 0.5 mol/L NaOH aqueous solutions. The two critical concentrations of L-FV-Ⅱ in 0.5 mol/LNaOH aqueous solutions were also found to be 1.2×10^(-3) g cm^(-3) fbr c_s and 9.2×10^(-3) g cm^(-3) for c~* from the concentrationdependence of phenanthrene fluorescence intensities. The overlap concentration c~* of L-FV-Ⅱ in 0.5 mol/L NaOH aqueoussolutions was lower than that of polystyrene with same molecular weight in benzene, owing to the fact that polysaccharidetends to undergo aggregation caused by intermolecular hydrogen bonding. A normal viscosity behavior of L-FV-Ⅱ in 0.5 mol/L urea/0.5 mol/L NaOH aqueous solutions can still be observed in an extremely low concentration range at 25℃.

Flavor changes in Lentinus Edodes enzymatic hydrolysate maillard reaction products with different sugars by gas chromatography‐ion mobility spectrometry

The characteristic flavor of the enzymatic hydrolysate of Lentinus edodes,which was involved in the Maillard reaction by xylose,fructose,glucose,sucrose,mannose,maltose,vitamin C(VC)and L-arabinose,was determined and analyzed by gas chromatography-ion mobility spectroscopy(GC-IMS).The characteristic flavor fingerprints of Maillard reaction products(MRPs)of L.edodes enzymatic hydrolysate were constructed.The differences in the characteristic flavors of Maillard reaction with different reducing sugars and VC were compared.The main characteristic flavor,characteristic peak,characteristic marker substance and content were determined,a principal component analysis(PCA)of volatile organic compounds(VOCs)was carried out.The results showed that there were 42 kinds of monomers and some dimers of volatile compounds in the samples including 17 aldehydes,5 alcohols,7 ketones,2 esters,2 acids,7 other compounds and 2 ethers.The volatile VOCs of the sample with added sucrose,VC and L-arabinose were significantly higher than those of the enzymatic hydrolysate of L.edodes.After the Maillard reaction,the flavor of the hydrolysate was significantly improved,and the main components changed significantly.

不同生长期香菇培养料中木质纤维素的变化特征

为探究不同生长期香菇培养料中木质纤维素的变化特征,促进其高效降解利用,以香菇培养料为研究对象,采用范式抽提法、X-射线衍射法、傅里叶变换红外光谱法和光学显微成像法对各生长期香菇培养料的木质纤维素含量、纤维素结晶度、木质纤维素相关的官能团和纤维形态变化进行分析。结果表明,随着香菇生长进程的推进,木质纤维素各组分含量显著下降,纤维素生殖生长阶段降解较多,半纤维素、木质素、综纤维素降解具有明显的阶段性,进入转色后降解速度加快。二茬菇时纤维素、半纤维素、木质素和综纤维素含量分别比原料降低了34.73%、61.58%、57.15%、42.33%。各生长期的香菇培养料均具有典型的纤维素X射线衍射特征,纤维素结晶区被破坏,典型衍射峰的结晶度持续减少。傅里叶变换红外光谱显示,木质纤维素的红外光谱特征官能团主要吸收峰的位置未发生改变,但振动强度减弱,与木质纤维素各组分的降解利用规律一致;特征峰比值I1723/I1510、I1383/I1510、I1157/I1510呈现不断减少趋势,而I897/I1510在转色和一茬菇呈增大趋势,表明香菇对木质纤维素各组分的降解程度不同,该生长期木质素相比纤维素有着更快的降解速率。纤维长度及宽度总体上呈现降低的趋势,二茬菇与其他生长期存在显著性差异。经显微镜观察,二茬菇纤维壁及内腔遭到破坏,明显区别于原料。因此,香菇对培养料木质纤维素具有较强的持续的降解作用,可显著降低木质纤维素含量,破坏纤维素结晶区,使得红外光谱吸收峰及纤维形态发生改变。

不同生长阶段香菇栽培料木质纤维素降解利用研究

为深入了解香菇生长发育过程中栽培料木质纤维素的变化,对不同生长阶段香菇栽培料中木质纤维素含量及其相关降解酶活性进行了测定,利用傅里叶变换红外光谱(FTIR)、X-射线衍射法(XRD)和显微镜观察研究了木质纤维素微观结构分子基团、纤维素相对结晶度(CrI)和纤维表面形态的变化。结果表明,在香菇生长发育过程中,栽培料中的纤维素、半纤维素和木质素含量显著下降,木质纤维素含量(w,后同)由85.27%降低至52.23%,其与相应的降解酶系活性负相关,木质纤维素降解与纤维破坏程度呈现一定的相关性。FTIR结果显示,不同生长阶段香菇栽培料中木质纤维素特征官能团峰值发生变化,木质素降解速率高于半纤维素、低于纤维素。随着香菇的生长发育,栽培料中CrI显著降低,纤维素晶体结构受到了一定程度的破坏。结果表明,香菇首先利用栽培料中非木质纤维素组分供菌丝生长,同时分泌胞外降解酶破坏纤维结构,将大分子组分降解为小分子组分,从而满足其生长所需,高木质纤维素降解酶活性对应高木质纤维素降解率。该研究结果可为促进香菇栽培料中木质纤维素的降解利用提供依据。

香菇菌糠中木质纤维素的挤压降解及结构表征

为开发香菇(Lentinus edodes)菌糠的新型加工处理方式,促进其高效转化利用,以香菇菌糠为研究对象,采用范式抽提法、傅里叶变换红外光谱法、X-射线衍射法和光学显微成像对经挤压处理香菇菌糠的木质纤维素含量、木质纤维素官能团、纤维素相对结晶度和纤维形态变化进行分析。结果表明,香菇菌糠经过挤压处理后木质纤维素各组分均有不同程度减少,40%水分挤压和50%水分挤压后木质纤维素含量分别降低了13.863%、11.264%,纤维素含量分别降低了19.003%、16.630%,综纤维素含量分别降低了17.357%、11.343%,木质素含量分别降低了6.574%、11.099%,纤维素相比半纤维素、木质素呈现出更快的降解速度;与50%水分挤压相比,40%水分挤压对半纤维素、综纤维素的降解作用更显著,降解率分别提高了12.131%、6.783%。傅里叶变换红外光谱显示,木质纤维素的红外光谱特征官能团主要吸收峰的位置未发生改变,但吸收峰特征及强度发生变化,表明挤压处理对香菇菌糠中木质纤维素各组分有降解作用,其中半纤维素在低水分条件下更易发生降解,与木质纤维素各组分的挤压降解规律一致。挤压前后的香菇菌糠均具有典型的纤维素X射线衍射特征,挤压后纤维素结晶区被破坏,40%水分挤压和50%水分挤压后纤维素相对结晶度分别降低了21.10%、18.00%。纤维长度、宽度及长宽比呈现出降低趋势,经显微镜观察,挤压后香菇菌糠纤维壁及内腔进一步遭到破坏,膨松状态片状结构明显增多增大。因此,挤压处理可有效降解香菇菌糠木质纤维素,破坏其生物质结构,使得红外光谱吸收峰、纤维素结晶度及纤维形态发生改变,其中,40%水分挤压的降解作用更佳。

香菇杂交菌株抗木霉能力筛选及可靠性分析

香菇育种中,抗木霉能力是筛选优良菌株的重要指标。为了提高菌株抗木霉能力筛选效率,通过香菇与木霉菌株在培养皿中的对峙培养,利用拮抗带宽度、香菇拮抗半径和木霉入侵距离3种方法对256株香菇杂交菌株进行抗木霉能力筛选。每种方法各筛选61株抗性强的菌株(合计101株)进行栽培试验,比较抗木霉能力的一致性、相关性和可靠性。结果表明,香菇拮抗半径、拮抗带宽度和木霉入侵距离3种方法测定的菌株抗木霉能力趋势线一致,相关系数分别为-0.699、0.536和-0.675,存在极显著较大相关,栽培污染群体指数分别为6.3、4.6和9.9,说明拮抗带宽度测定方法筛选的菌株抗木霉能力更强,其次为香菇拮抗半径,最差为木霉入侵距离。

谷氨酰胺转氨酶交联对香菇蛋白理化特性和加工特性的影响

为开发和利用香菇蛋白,研究谷氨酰胺转氨酶交联对香菇蛋白理化特性和加工特性的影响。结果表明,添加0%~20%的谷氨酰胺转氨酶,香菇蛋白总巯基、游离巯基、β-折叠逐渐降低,荧光强度、粒径、β-转角和表面疏水性呈先升高后降低的趋势。随着剪切速率的增加,蛋白的剪切应力增加,表观黏度降低,说明谷氨酰胺转氨酶交联促进了大分子聚合物的生成,且交联蛋白表现出与初始蛋白相似的致密质地,表明它们形成了稳定的三维网络结构。随着添加量增加(4%~12%),蛋白质的网状结构越来越繁密。此外,适量的谷氨酰胺转氨酶使香菇蛋白的溶解性、乳化性、热稳定性和持油性都得到了显著提高。结果表明,谷氨酰胺转氨酶交联不同程度地改善了香菇蛋白的理化特性和加工特性。

酶解香菇调味酱的研制及流变学特性研究

该研究旨在开发一种新型酶解香菇调味酱。结果表明,产品的最佳配方为食盐4.0%、白砂糖1.5%、I+G 0.6%、柠檬酸0.06%、复配增稠剂(黄原胶∶海藻酸钠为4∶6)0.8%、香料油10%。香菇调味酱的流体类型为剪切稀化的假塑性流体,具有触变性,表现为类固体的凝胶特性。此外,该香菇调味酱对DPPH自由基、羟基自由基和超氧阴离子自由基有一定的清除能力。香菇调味酱的蛋白质、脂肪、还原糖和总酸含量分别为24.81,10.20,1.80 g/100 g和6.70 g/kg。

香菇柄贡菜牛肉酱制作工艺研究

文章以香菇柄、贡菜和牛肉为主要原料制作香菇柄贡菜牛肉酱。选定了对产品品质影响最大的香菇柄添加量、牛肉添加量、豆瓣酱添加量和蒜蓉辣椒酱添加量作为实验对象,通过单因素实验和正交实验确定了主料和辅料的最优配比。结果表明,各原料最佳配比为香菇柄添加量15%、牛肉添加量25%、豆瓣酱添加量10%和蒜蓉辣椒酱添加量15%,按照此配比制作的产品感官评价结果最好。在香菇柄牛肉酱中加入贡菜,既能赋予产品更高的营养价值,也能使产品的口感更加脆爽,制作的香菇柄贡菜牛肉酱鲜香麻辣,色泽诱人,符合大众的口味。

基于火候和配方调控的香菇基素鲍鱼制备工艺研究

该研究通过单因素试验和正交试验探究不同火候和工艺配方对香菇基素鲍鱼感官品质的影响并确定其最佳生产条件。经过感官评价小组的综合评分,最终确定香菇基素鲍鱼的最佳工艺配方为电磁炉功率1 500 W、鲍鱼素添加量1.5%、调味料添加量14%、淀粉添加量3%。该条件下生产的香菇基素鲍鱼符合食品安全国家标准GB 2760—2014,色泽均匀,香味浓郁协调,咸鲜适中,口感脆嫩弹牙,有一定鲍鱼肉质感,能够迎合大众口味,具有规模化生产的潜力。

改进YOLOv5的香菇子实体生育期识别方法

在香菇栽培中,需要评估其生长发育状态,以便调控栽培环境和采取适当的栽培措施。针对香菇生育期子实体外观特征变化不显著,机器自动采收时部分成熟期香菇子实体易误检和漏检的问题,该研究提出了一种基于改进YOLOv5的香菇子实体生育期识别方法。首先替换YOLOv5模型中上采样模块,采用一种包含上采样预测模块和特征重组模块的轻量级上采样模块;其次在YOLOv5l模型中添加小目标检测层,增加模型对香菇子实体生育期特征信息的提取,提高模型区分香菇生育期和识别小香菇的能力。试验结果表明,改进的YOLOv5l模型具有较好的检测能力,平均帧率为45.25帧/s,平均精确度均值为92.70%,与YOLOv5相比平均精确度均值提升2.5个百分点。该研究方法能够满足对香菇子实体不同生育期识别的精度与速度要求,为香菇子实体生育期识别提供了一种方法参考。

不同香菇品种拮抗反应·ISSR标记与农艺性状分析

为区分常用香菇品种L808和申香215,以香菇武香一号为对照,对3个品种进行了拮抗试验、ISSR分析和农艺性状比较,结果表明:武香一号与L808和申香215拮抗反应明显,L808与申香215品种间无明显拮抗反应;在农艺性状比较方面,同一栽培条件下,品种L808和申香215在形状、颜色性状上无明显区别,但是在菌丝体长速、生长发育各个阶段时间节点、子实体大小、单菇重、生物学效率等性状上存在明显差异;在ISSR分子标记中申香215和L808存在特异性条带,能够有效区分2个品种。

香菇速食酸汤块的研制及其品质分析

为拓宽贵州特色风味发酵酸汤的开发及利用领域,研制一款兼有酸汤、香菇风味且食用方便、营养健康的速食汤块。首先通过单因素试验和正交试验确定其最优配比,再分析产品的理化指标、质构特性和挥发性成分。结果表明,香菇速食酸汤块的最优配方(以添加水的质量计)为35%酸汤、40%香菇和1.82%辅料(味精∶姜末∶食盐为1∶1∶2.4)。最终产品的蛋白质、脂肪和还原糖含量分别为(3.77±0.016),(4.04±0.32),(3.97±0.19)g/100 g;菌落总数≤1×10^(3) CFU/g,大肠菌群、金黄色葡萄球菌等均未检出。汤块中菌菇复水后的咀嚼度高于新鲜香菇(P<0.05),而弹性和硬度无显著差异,说明加工后的产品具有较好的弹性和口感;产品的颜色呈瓦红色,比传统酸汤的色泽更鲜亮;氮氧化物(R2)、无机硫化物、吡嗪类、萜烯类物质(R7)是汤料中主要的风味组分。研制的香菇速食酸汤块色泽良好,整体风味独特,品质较好,不仅丰富了地方民族风味酸汤系列产品,而且对香菇的精深加工产业提供了有益参考。