利用甘薯酸浆中分离的乳酸菌发酵薯汁酸奶的研究

以自然发酵甘薯酸浆中分离的乳酸菌L·paracasei subsp·paracasei L1发酵薯汁,研究利用L·paracasei subsp·paracasei L1发酵薯汁生产薯汁酸奶的条件,开发出具有独特风味、良好保健作用和广阔市场前景的乳酸菌饮品。      

对甘薯淀粉具有絮凝活性的乳酸菌的分离鉴定及其特性研究

从自然发酵甘薯酸浆中分离筛选到一株对甘薯淀粉颗粒具有高絮凝活性的乳酸菌L1,经鉴定该菌为副干酪乳杆菌副干酪亚种(Lactobacillus paracasei subsp. paracasei)。该菌株产絮凝剂的适宜pH值为6.5～8.5,适宜培养温度为25～35℃。葡萄糖、蔗糖、麦芽糖及乳糖均可作为该菌株的良好碳源,其适宜氮源为酵母粉或牛肉膏。通过对絮凝活性分布的研究,确定菌株所产的絮凝剂主要存在于菌体上。     

固定化乳酸菌发酵胡萝卜酸奶工艺研究

通过固定化乳酸菌发酵胡萝卜酸奶,建立新的胡萝卜酸奶发酵工艺。经过单因素试验和正交试验,确定固定化乳酸菌发酵胡萝卜酸奶的配方和发酵工艺。胡萝卜酸奶的配方：奶粉9g、胡萝卜13g、白砂糖8g、蒸馏水100mL。胡萝卜酸奶发酵工艺：固定化德氏乳杆菌保加利亚亚种与固定化唾液链球菌嗜热亚种的比为2:1 接种发酵液(菌种的总添加量为6g/100mL)、在37℃发酵培养7h、然后4℃冷藏12h。结果表明,采用固定化乳酸菌新技术可以发酵生产营养丰富、口感良好的胡萝卜酸奶。     

豆腐乳中乳酸菌的分离鉴定与发酵特性研究

目的分离鉴定农家自制传统发酵豆腐乳中的乳酸菌,探讨其作为豆类乳酸菌发酵饮品菌株的可行性。方法利用MRS(man rogosa sharp)培养基分离豆腐乳中的乳酸菌,通过形态学观察、生理生化特性和16S rDNA基因序列分析进行鉴定,并将所分离到的乳酸菌与适合于豆类植物发酵的植物乳杆菌FJAT-7926(Lactobacillus plantarum FJAT-7926)和干酪乳杆菌FJAT-7928 (Lactobacillus casei FJAT-7928)进行发酵特性的对比研究。结果从豆腐乳中分离出1株乳酸菌,命名为FJAT-46777,该菌株菌体细胞为圆端直杆状或圆端弯曲杆状,无芽孢,革兰氏阳性,过氧化氢酶阴性,生理生化特征与发酵乳杆菌(Lactobacillus fermentum)一致,对菌株的16S rDNA基因进行扩增测序、分子系统发育树分析,也表明其为发酵乳杆菌。发酵乳杆菌FJAT-46777发酵的豆乳中乳酸菌增殖速度最快,最终活菌数最高,为9.42 lg(CFU/mL); pH值下降最快,最终pH值最低,为3.91;滴定酸度上升速度最快,最终滴定酸度最高,为62~ΟT。结论分离自豆类自然发酵食品中的发酵乳杆菌FJAT-46777,对豆类植物为主的基质具有更优良的发酵特性,发酵时间快,乳酸菌含量高,产酸能力强,适用于发酵豆乳的开发。     

副干酪乳杆菌副干酪亚种L1的培养条件及絮凝活性研究

酸浆是我国传统的鲜薯(或绿豆)淀粉生产工艺中用于淀粉分离净化的生物絮凝剂。本实验对从自然发酵的甘薯酸浆中分离的、对甘薯淀粉具有高絮凝活性的副干酪乳杆菌副干酪亚种L1的培养条件和絮凝活性进行了研究。结果表明,副干酪乳杆菌副干酪亚种L1为兼性厌氧菌,在改良TJA培养基初始pH为7.0,在25℃培养48～60h时,菌体的生长状况和絮凝活性最好;Na+、K+对L1的絮凝活性有显著的增强作用,但对高温和胰蛋白酶敏感。     

副干酪乳杆菌副干酪亚种L1的培养条件及絮凝活性研究

酸浆是我国传统的鲜薯（或绿豆）淀粉生产工艺中用于淀粉分离净化的生物絮凝剂。本实验对从自然发酵的甘薯酸浆中分离的、对甘薯淀粉具有高絮凝活性的副干酪乳杆菌副干酪亚种L1的培养条件和絮凝活性进行了研究。结果表明,副干酪乳杆菌副干酪亚种L1为兼性厌氧菌,在改良TJA培养基初始pH为7.0,在25℃培养48～60h时,菌体的生长状况和絮凝活性最好;Na+、K+对L1的絮凝活性有显著的增强作用,但对高温和胰蛋白酶敏感。      

干酪乳杆菌发酵制备酸奶味香精基料的研究

以黄油为底物,利用干酪乳杆菌对其进行发酵,通过单因素试验和正交试验,以感官评价和酸价为指标,探究出生产酸奶味香精基料的最佳工艺条件.结果表明:添加以乳清粉为辅底物,黄油与乳清粉比例为2:1,黄油浓度为25％,干酪乳杆菌接种量为15％,发酵温度为37℃,发酵时间为28 h的条件下所制得的酸奶味香精基料风味最佳.     

副干酪乳杆菌对甘薯浆液中淀粉絮凝机理研究

为探讨酸浆法分离甘薯淀粉传统工艺中的淀粉沉降分离机理,进一步制备高效生物絮凝剂。本实验采用Zeta 电位测定、粒度分析及离子键检测研究副干酪乳杆菌对甘薯淀粉絮凝沉淀的作用。结果表明：絮凝过程基于“架桥”机理,淀粉颗粒与菌体间靠离子键结合,絮凝作用使悬浊液中淀粉平均粒径减小,密度增大,导致淀粉颗粒凝聚沉降;通过热处理和酶处理实验分析菌体起絮凝作用的活性成分组成,表明副干酪乳杆菌活性成分为蛋白类物质。     

副干酪乳杆菌FMLP4菌株在泡菜和酸奶发酵中的应用初探

目的:本文研究副干酪乳杆菌FM-LP-4对发酵泡菜和酸奶品质及体外抗氧化能力的影响。方法:利用副干酪乳杆菌FM-LP-4作为发酵菌株发酵泡菜,保加利亚乳杆菌、嗜热链球菌和干酪乳杆菌FM-LP-4混合发酵酸奶,检测发酵泡菜和酸奶的发酵时间、抗氧化能力等指标的变化,同时对发酵产品进行感官评定。结果:副干酪乳杆菌FM-LP-4能显著缩短泡菜发酵时间(p<0.05),降低硝酸盐含量(p<0.05),并能显著提高发酵泡菜的硬度和体外抗氧化能力(p<0.05),感官评分高于自然发酵泡菜。综合分析,接种量3.0%~5.0%为蔬菜发酵的合适接种量。副干酪乳杆菌FM-LP-4能显著提高发酵酸奶的粘度(p<0.05)、保水率和体外抗氧化能力(p<0.05),同时提高酸奶的感官评分。综合分析,保加利亚乳杆菌、嗜热链球菌和副干酪乳杆菌FM-LP-4的接种比例为1:1:1时为酸奶发酵的合适接种比例。结论:副干酪乳杆菌FM-LP-4在抗氧化功能产品开发中具有较好的应用前景。     

干酪乳杆菌在酸奶生产中的应用研究

用干酪乳杆菌生产新型发酵酸奶,通过单因素实验、正交实验、验证性实验等方法对不同的发酵条件进行实验研究,以风味、酸度、活菌数量为产品指标,确定出最佳的发酵工艺条件。结果表明,接种量为5%,发酵时间9h,发酵温度为36℃时为理想工艺参数组合。     

甘薯酸浆中微生物絮凝性研究

酸浆是我国传统的鲜薯(或绿豆)淀粉生产工艺中用于淀粉分离净化的生物絮凝剂.为了研究酸浆中微生物的絮凝性,本研究以甘薯酸浆为研究对象,模拟实际生产中酸浆的发酵工艺,对自然发酵甘薯酸浆中微生物消长规律进行分析.结果表明,酸浆中乳酸菌含量最高,其次为酵母菌,霉菌含量最低.在酸浆絮凝活性最高时,对其中的微生物进行分离纯化,从中共分离出1株乳酸菌、2株酵母菌和1株霉菌.通过对各菌株絮凝性的研究发现,只有乳酸杆菌L1具有絮凝活性,并且其絮凝活性物质分布在菌体上,酵母菌Y1对乳酸菌的生长具有促进作用,二者呈互生关系.     

红薯乳酸菌发酵酸奶的研制

以红薯液、牛乳为原料,发酵制得营养丰富、口味独特的红薯酸牛奶;将保加利亚乳杆菌和嗜热链球菌按1∶1的比例3%的接种量接入原料中,结果表明:红薯液与牛乳以5:5混合、发酵温度39℃、发酵时间12 h比较适宜.     

发酵红薯饮料的研究

探讨了不同乳酸菌在红薯基质中的产酸情况以及基质的酶解处理对产酸的影响,同时将发酵基质调糖后制成饮料以评价其品质。结果表明,在实验涉及的5种乳酸菌中,干酪乳杆菌产酸量最高且能保持基质原来的颜色;基质的酶解处理未能提高产酸量;发酵基质调制的饮料在色、香、味及接受性等方面均较佳。     

Characteristics of mung bean starch isolated by using lactic acid fermentation solution as the steeping liquor

Physicochemical properties of commercial mung bean starch isolated with lactic acid fermentation solution (LFS) and starches laboratory-prepared by using NaOH, Na₂SO₃ and distilled water as steeping liquors were examined with the aim of elucidating the effect of different steeping liquors on the properties of starches. Results indicated that the amylose content, granular morphology and X-ray diffraction pattern of starches isolated with different steeping liquors did not show obvious differences. However, the LFS-isolated starch had significantly (p < 0.05) higher weight percentage of longer B chains and B₁ chains, a lower weight percentage of A chains and a lower ratio of short-to-long chains in amylopectin than those of the other preparations. Moreover, the LFS-isolated starch showed significantly (p < 0.05) lower pasting viscosity, a higher onset temperature, a narrower temperature range and a lower enthalpy of gelatinization than the other preparations. No significant differences on the physicochemical properties mentioned above were found among the laboratory-prepared starches. The results suggest that mung bean starch is degraded during isolation with lactic acid fermentation solution, which leads to the loss of starch granules with less integrity.     

Selective enumeration and identification of mixed cultures of Streptococcus thermophilus,Lactobacillus delbrueckii subsp. bulgaricus,L. acidophilus,L. paracasei subsp. paracasei and Bifidobacterium lactis in fermented milk

This study describes selective plating methodologies for enumeration of mixed cultures of Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, L. acidophilus, L. paracasei subsp. paracasei and Bifidobacterium lactis in fermented milk based on selective antibiotic-free media. Enumeration of S. thermophilus was performed using M17-lactose. MRS-fructose was suitable for enumeration of L. bulgaricus and MRS-maltose for differentiation between L. acidophilus and L. paracasei. The selective enumeration of B. lactis was obtained using MRS-raffinose containing 0.05% LiCl. The bacterial counts obtained using selective methods were equivalent to those under optimum culture conditions at a probability level of 95%. Performance of the methods was verified in fermented milk products where identification of the enumerated species was confirmed by species-specific polymerase chain reaction. This study shows that combination of species-specific polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) analysis has great detection and identification potential for verification of accurate species labelling in fermented milk without prior isolation of the bacteria.     

副干酪乳杆菌坚韧亚种FX-6发酵提取物对鲜虾的保鲜评价

将经过0.5%FX-6发酵提取物浸泡处理的鲜虾于4℃冷藏,隔天测定其p H、TVB-N值、细菌总数等鲜度指标及进行感官评价。同时,以相同浓度的山梨酸钾、乳酸链球菌素为阳性对照组。实验结果表明:随着鲜虾冷藏时间的延长,其p H、TVB-N值、细菌总数等鲜度指标均出现不同程度的上升,以TVB-N值为25 mg/100 g和菌落总数为106 CFU/g作为判断货架期终点的界限,空白对照组冷藏第6 d时其TVB-N值和菌落总数已超过界限,0.5%山梨酸钾、0.5%乳酸链球菌素组第8 d时超过界限,而0.5%FX-6发酵提取物组则在第10 d时才超过界限。因此,综合各项鲜度指标及感官评分可知,经过0.5%山梨酸钾、0.5%乳酸链球菌素处理后的鲜虾的货架期可由4 d延长至6 d,而0.5%FX-6发酵提取物能够延长鲜虾货架期至8 d。说明0.5%FX-6发酵提取物对鲜虾具有较好的保鲜效果,优于0.5%山梨酸钾、0.5%乳酸链球菌素。      

Cryoprotective effect of turanose on lyophilized Lactobacillus paracasei subsp. paracasei,L. casei 431

Food Science and Biotechnology - The lyophilization process is the most convenient and successful method to preserve probiotics, although microorganisms are exposed to conditions of extremely low...     

玉米肽对益生菌酸奶影响的研究

研究了玉米肽对发酵乳的发酵时间、粘度、风味、口感以及稳定性的影响,研究表明,添加1.2%的玉米肽对促进酸乳发酵有良好效果,发酵时间比对照样要缩短1h多,酸乳菌和益生菌的活菌数都能超过成品酸乳标准要求。添加玉米肽对发酵乳的粘度影响不大,对发酵乳的稳定性影响也不大,但对发酵乳的口感和风味有一定影响,主要体现在稠厚感和苦涩味上,并且样品在贮存期内各项性能都比较稳定。      

Effect of antioxidant activity and functional properties of Chingshey purple sweet potato fermented milk by Lactobacillus acidophilus, L. delbrueckii subsp. lactis, and L. gasseri strains

In this study, individual selected lactic acid bacteria strains Lactobacillus acidophilus (LA), L. delbrueckii subsp. lactis (LDL), and L. gasseri (LGA) were grown in Chingshey purple sweet potato (CPSP) substrate/media. CPSP is rich in anthocyanin, which possesses antioxidant activity and in vitro cell assay. The antioxidant ability and functional properties of the fermented milk were examined. High-performance liquid chromatographic (HPLC) method was used to analyze the free amino acid, organic acids, and anthocyanin content. Total phenolic compounds, scavenging effects of 1,1-diphenyl-2-picyl-hydrazyl (DPPH) radicals, and scavenging effects of superoxide anion radicals were determined to evaluate the antioxidant ability of the samples. The cell proliferation of the fermented PSP milk was evaluated by 3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyl Tetrazolium Bromide (MTT) assay. The result indicated that the antioxidant ability of the fermented CPSP milk through LA, LDL, and LGA strains was significantly higher than CPSP. The main anthocyanins present in the samples are cyanidin and delphinidin. MTT assay has revealed that incubation with both PSP and fermented CPSP milk prevented the cell death of macrophage-like RAW264.7 cells. The potential health benefit of fermented PSP milk through LA, LDL, and LGA strains makes the further application of CPSP in health food highly worthwhile. PRACTICAL APPLICATION: (1) In our study, we have employed the γ-aminobutyric acid (GABA), organic acid contents, total phenol content, anthocyanins content, DPPH, oxygen radical absorbance capacity, superoxide dismutase activity assay, and cytotoxicity assay to assess the functional properties of fermented CPSP milk by different lactic acid bacteria. (2) Our results have revealed that the fermented CPSP milk samples possess high GABA concentrations, organic acid contents, anthocyanins contents, and antioxidant activity. This will provide potential opportunity to develop different functional food products from fermented CPSP milk. (3) The potential health benefit of fermented CPSP milk makes the further application of CPSP in health food highly worthwhile.