乳酸菌肉品发酵剂的选择

从发酵肉制品中分离、纯化乳酸菌132株,对它们的主要发酵特性进行了测定,以生产干发酵香肠誓前篓,从中选出4株乳酸菌优选菌株R17、P20、P30和J33。4株菌生长速度有显著差异,温度对其生长速度有显著的影响。其中R17和P20之间没有拮抗关系,可以作为混合发酵剂。P30和J33可以作为单菌发酵剂。     

耐热乳酸菌肉品天然发酵剂的筛选鉴定

为获得发酵性能优良且具有较好耐热性的肉品发酵剂乳酸菌,通过溶钙圈法分离,乳酸纸层析、耐盐耐硝性、生物胺检测、产黏性、发酵葡萄糖产气、产H2S、抑菌实验初筛和产酸能力、耐热能力实验复筛,最终从5种传统发酵肉筛选出2株具有良好发酵特性和耐热性的菌株Y9、FL6。结合形态学、生理生化特征和16S rRNA序列分析鉴定后确定Y9为植物乳杆菌,FL6为戊糖片球菌。这两株菌都能在含6g/dL NaCl和150mg/kgNaNO2的MRS培养基中良好生长,其产酸速度快,24h内能将pH值降到4.0左右,还能抑制大肠杆菌和金黄色葡萄球菌的生长。经过水浴80℃处理1min后,发现菌株Y9、FL6活菌数依然维持在103、105CFU/mL左右,表现出较好的高温耐受力,可将两株菌复配后经喷雾干燥制成发酵剂菌粉。     

发酵白菜乳酸菌的培养基及发酵剂的筛选

成功地筛选出理想液体培养基1号、生产种子培养基2号;利用选定的三株乳酸菌组成不同配比的发酵剂发酵白菜。依据pH值、感官指标等综合评定,筛选出理想发酵剂sp1:sp2:sp3=1:1:1接种发酵白菜效果最好。     

功能性乳酸菌发酵剂在食品发酵工业中的应用

功能性乳酸茼发酵剂是具有一种或几种固有功能特性的发酵剂，其在感官、技术、营养或健康方面的各种优势使之在食品发酵工业中的应用潜力巨大：它可用于食品防腐、提高食品安全性，改善食品质构和风味，加速奶酪成熟，可产生功能因子、去除毒副因子从而使食品具有保健功效；某些抗噬菌体发酵剂还可解决乳品工业中的噬菌体污染问题。通过基因工程或菌株筛选可以获得所需的功能性发酵剂．它使人们可以更好地控制发酵过程，为消费者提供新型健康食品，此外还有利于食品企业的多样化生产。     

乳酸菌发酵剂高密度培养的研究

研究了乳酸菌生长繁殖的环境条件(温度、接种量、起始pH等)和培养基组成(氮源、碳源、缓冲盐等),优化确定了乳酸菌发酵剂的适宜培养条件为:起始pH值为6.5,培养温度为37℃,培养基配比为麦芽糖∶乳糖(1∶1)2%、牛肉膏1.0%、缓冲盐A0.5%、NaCl0.25%、MgSO40.1%,接种量4%,进一步探索了半连续法进行高密度培养,结合优化的培养条件,可使乳酸菌的液体发酵活菌密度至1.1×1012CFU/mL。     

浓缩乳酸菌发酵剂的制备

本文着重叙述国外四种制备乳酸菌浓缩发酵剂的方法，即：离心分离法、化学中和法、缓冲盐法及渗析法，其特点及存在的问题，以促进我国开展浓缩乳酸菌发酵剂的研究和生产。     

基因工程对乳酸菌发酵剂的改良应用

介绍了基因工程技术在乳品发酵工业中的应用，并对利用基因工程技术改良乳酸菌发酵剂产生双乙酰的能力、蛋白水解能力、胞外多糖的形成、抗杂菌和病原菌污染特性4个方面的进行研究阐述，还将要介绍了基因工程食品可能存在的不安全问题及解决方法。     

浓缩乳酸菌发酵剂的现状

总结了浓缩乳酸菌发酵的应用及研究概况，并对不同的加工方法加以分析。     

浓缩型乳酸菌发酵剂的工业化生产

对乳品发酵剂工业化生产中的重要技术，诸如高活力菌体的增殖培养、发酵过程控制与分析、细胞富集和生物保存等问题进行了探讨．以期为我国进一步发展浓缩型乳酸菌发酵剂提供理论依据。     

发酵肉制品中发酵剂的研究

本文介绍了发酵肉制品中常见的几种发酵剂的种类、作用及其对发酵肉制品的品质、风味、组织状态的影响。     

不同酸奶发酵剂的发酵性能比较

前期在单菌株筛选的基础上,获得7种保加利亚乳杆菌与嗜热链球菌组合的酸奶发酵剂。利用这7种发酵剂发酵制备酸奶,评价他们的产酸性能、后酸化能力,并分析所制备酸奶的物性学特性、乙醛和双乙酰产量,最后进行感官评价,以评价这些发酵剂的工业应用潜力。结果表明,7种酸奶发酵剂具有各自独特的发酵性能,可用于不同风味和质地酸奶的生产,具有工业开发潜力。     

开菲尔功能菌组的复合及发酵特性研究

研究了开菲尔粒子中不同分离菌种的发酵情况,对不同比例的乳酸菌、酵母发酵产物的质量指标(如风味、酸度和发泡性)进行了评价,不同比例分离菌种(30～50g/L)在均质乳中(30℃,16h)连续发酵培养,分析检测其中的蛋白质、脂肪、粗多糖、酒精、黏度和VB含量。结果表明,L-1∶L-2∶L-3∶L-4∶L-5∶Y-1∶Y-2=1∶1∶1∶1∶1∶1发酵产物经评价其质量和感官特性最接近开菲尔。     

Effect of selected autochthonous starter cultures on processing and quality characteristics of Greek fermented sausages

Selected autochthonous starter (SAS) cultures (i.e. Lactobacillus sakei 8416, Lactobacillus sakei 4413, and L. sakei 8426, L. plantarum 7423 and L. curvatus 8427) were used as starter cultures in addition to a control treatment in the production of fermented sausages. The SAS cultures had a rapid growth and dominated the fortuitous population of LAB during the whole fermentation and ripening process improving the sensory attributes in comparison to control. Apart from the treatment produced with L. sakei 8416, all other SAS cultures prevented the lipid oxidation to values lower than 1 mg malonaldehyde/kg. The Micrococcaceae count and the redness of the sausages was not affected by the smoking and the acidification during the fermentation in the treatments produced with L. sakei 8416 and L. sakei 4413. The treatment of L. sakei 4413 had the lowest (*P < 0.05) content of all biogenic amines. In comparison to the control, the reduction of tyramine was 13%, tryptamine 55%, cadaverine 60% and putrescine 72%. Sausages produced with SAS cultures L. sakei 4413 and L. sakei 8416 had the highest scores for all sensory attributes. The results indicated that the SAS culture of L. sakei 4413 is the best autochthonous starter culture for fermented sausages.     

Prevalence and impact of single-strain starter cultures of lactic acid bacteria on metabolite formation in sourdough

Flavour of type II sourdoughs is influenced by the ingredients, processing conditions, and starter culture composition. It is, however, not fully clear to what extent different sourdough lactic acid bacteria (LAB) contribute to flavour. Therefore, two types of flour (rye and wheat) and different LAB starter culture strains were used to prepare sourdoughs, thereby leaving the yeast microbiota uncontrolled. All LAB starter culture strains tested were shown to be prevalent and to acidify the flour/water mixture to pH values between 3.1 and 3.9 after 24 h of fermentation. Multiple aldehydes, alcohols, ketones, and carboxylic acids were produced by the sourdough-associated microbiota throughout the fermentation period. Based on the organoleptic evaluation of breads produced with these sourdoughs, five LAB strains were selected to perform prolonged wheat and rye fermentations as to their capacity to result in an acidic (Lactobacillus fermentum IMDO 130101, Lactobacillus plantarum IMDO 130201, and Lactobacillus crustorum LMG 23699), buttermilk-like (Lactobacillus amylovorus DCE 471), or fruity flavour (Lactobacillus sakei CG1). Upon prolonged fermentation, higher metabolite concentrations were produced. For instance, L. sakei CG1 produced the highest amounts of 3-methyl-1-butanol, which was further converted into 3-methylbutyl acetate. The latter compound resulted in a fruity banana flavour after 48 h of fermentation, probably due to yeast interference. Rye fermentations resulted in sourdoughs richer in volatiles than wheat, including 3-methyl-1-butanol, 2-phenylethanol, and ethyl acetate.     

Influence of an autochthonous starter culture and a commercial starter on the characteristics of Tenerife pasteurised goats’ milk cheese

Two batches of Tenerife cheese were produced from pasteurised goats’ milk, one with a commercial starter and another with an autochthonous starter consisting of three selected strains of lactic acid bacteria isolated from artisanal Tenerife cheese. Influence of starter on the characteristics of the cheeses was evaluated. Owing to the composition of the starters, lactobacilli and leuconostocs varied significantly between both cheeses. However, the type of starter did not significantly affect the physicochemical and proteolytic properties of the cheeses. In general, cheeses made with autochthonous starter received higher scores for sensory attributes, especially for aroma, than those made with commercial starter.     

Selection criteria for lactic acid bacteria to be used as functional starter cultures in dry sausage production: An update

Lactic acid bacteria (LAB) have long been used as starter cultures in the production of fermented dry sausages and other meat-derived commodities. These cultures are generally designed to meet food safety, shelf-life, technological effectiveness and economic feasibility criteria. Besides all these traditional properties, novel starter cultures should take into account the risks posed by the formation of biogenic amines in food, and the development and spreading of bacterial resistance to antibiotics. Further, 'functional starters' could protect consumers from harmful bacteria either by a rapid acidification or by the production of antimicrobials (bacteriocins). Specially-selected cultures may also provide probiotic benefits, and, if properly modified, they may even be endorsed with nutraceutical traits. The present review discusses the technological and new selection criteria that should be taken into account when selecting LAB starter cultures for the production of fermented dry sausages.     

新疆传统乳制品中优良乳酸菌的筛选及多菌株发酵剂的研究

从新疆地区采集的46份传统乳制品中分离获得的612株乳酸菌,根据菌株来源、培养条件,形态特征、凝乳状态和产酸特性,选择其中20株乳酸菌进行生理生化鉴定和酸奶发酵试验,结果表明,分离株中3株为链球菌,4株为乳球菌,13株为乳杆菌,平均发酵产酸速率在8.11~12.43oT/h,不同菌株在酸乳冷藏期间表现出不同的后酸化活性,冷藏15d滴定酸度提高了6.3%~55.7%。不同菌株凝乳时黏度在272~1085cp,多数菌株发酵乳在冷藏期间黏度呈上升趋势,球菌的产黏能力普遍低于杆菌。气相色谱分析结果显示不同菌株发酵乳中丁二酮在3.51~68.74mg/L,乙醛在3.51~68.74mg/L,丙酮在0.87~48.35mg/L,乙酸乙酯在0~103.68mg/L,异戊醇都未检出。经过混合菌株发酵生产酸乳比较,发现以S.thermophilusX1、S.thermophilusX5、L.plantarumY5和L.delbrueckii bulgaricussubsp.Y10按1∶1∶1∶1比例组合作为发酵剂,生产的酸乳组织状态较好、风味独特、后酸化弱。