EFFECT OF THE USE OF DIFFERENT LACTIC STARTERS ON THE MICROBIOLOGICAL AND PHYSICOCHEMICAL CHARACTERISTICS OF NATURALLY BLACK TABLE OLIVES OF GEMLIK CULTIVAR

The effect of different lactic acid bacteria cultures on the physicochemical and microbiological characteristics of brined black olives of Gemlik cultivar at low fermentation temperature was studied. Fermentation was carried out according to the traditional Gemlik method with modifications like low salt concentration and lactic starter addition. The brines with 7% salt concentration were inoculated with lactic acid bacteria ( Lactobacillus brevis, Leuconostoc cremoris and L. paramesenteroides ), which were previously isolated from olive fruits at low temperatures and a commercial strain of Lb. plantarum. Fermentation procedures were carried out at controlled temperatures (between 10–12C). Lactic acid bacteria survival was accompanied by yeast development, no Pseudomonas and Enterobacter species were detected in all treatments during fermentation. The highest total titratable acidity, lowest pH and least yeast growth were determined at the brines and fermentation products, which were inoculated with L. cremoris.

PRACTICAL APPLICATIONS

The use of suitable starter cultures is necessary to improve the microbiological control of the naturally black table olive process, help to standardize the fermentation, increase the lactic acid yield and accordingly provide the production of olives with high quality. The requirements mentioned for starter cultures include a rapid and predominant growth, homofermentative metabolism, tolerance to salt, acid and polyphenols, and few growth factor requirements. Especially at the regions where olives were picked later when environmental temperatures are lower, the use of a starter culture that has the ability to grow at low temperatures may be necessary. Use of such starter cultures may help to increase acidification, to control some types of spoilage and to shorten the fermentation process.     

Proteolytic activities in togwa,a Tanzanian fermented food

Proteolytic activities were investigated in sorghum-based togwa prepared by natural fermentation and using starter cultures previously isolated from the native product, i.e., Lactobacillus brevis, Lactobacillus cellobiosus, Lactobacillus fermentum, Lactobacillus plantarum, Pediococcus pentosaceus, and Issatchenkia orientalis in coculture with either L. brevis or L. plantarum.Both proteinase and aminopeptidase activities were substantially higher in naturally fermented togwa than in those with starters (14-30%, 12-70%, respectively). A variable but substantial part of the proteinase activity followed the particulate fraction of togwa; aminopeptidase activity was mainly in that fraction. The breakdown of relatively high molecular mass protein (64 kDa) in togwa was detected by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE); the products were mainly in the 14-30 kDa range. Reversed-phase fast-protein liquid chromatography (RP-FPLC)-protein/peptide patterns changed during fermentation with some variation between togwa of different cultures. Supplementation of gruel with malt increased the concentration of total protein [from 9.5% to 11.0% (w/w) on dry weight basis)] and of most of the free amino acids. Fermentation had no effect on total protein content; however, the concentration of most of the amino acids was reduced, except for the proline content that increased. Natural fermentation also increased the concentration of glutamic acid and ornithine. Fermentation by P. pentosaceus increased aspartic acid, while L. cellobiosus, L. fermentum, and L. brevis in coculture with I. orientalis increased the concentration of citrulline.     

EFFECT OF LACTIC ACID FERMENTATION OF CASSAVA ON FUNCTIONAL AND SENSORY CHARACTERISTICS OF FUFU FLOUR

The effects of lactic acid fermentation of cassava on the functional and sensory characteristic of fufu flour were investigated. Two strains of Lactobacillus plantarum were used as starter cultures for the fermentation of cassava to fufu for 96   h. The resultant wet fufu samples were dried at 65C in a cabinet dryer for 48   h, and were analyzed for functional and sensory characteristics.
Fermentation reduced the water-binding capacity of the fufu flour from 176.6% to between 118 and 125%. The pasting characteristics of the traditional and starter culture-fermented fufu flour samples were not significantly different from that of the unfermented cassava flour. When subjected to sensory evaluation, the traditional and starter culture-fermented cassava fufu flour were not significantly different in terms of color, odor and texture, but the cassava fufu flour produced, using starter culture SL19, had the highest overall acceptability ( P <  0.05).

PRACTICAL APPLICATIONS

Traditionally, processing of cassava to fufu is usually carried out by using the old stock from a previous fermentation to initiate the fermentation of a new batch. This old method usually results in fufu that has a strong odor that may not be acceptable to some consumers. The use of starter culture like Lactobacillus plantarum will reduce the strong odor of fufu ; this will increase its acceptability by consumers and ensure the overall quality. Also, the functional properties of fufu are not affected. The development of lactobacilli strains could help in optimizing the traditional processes, therefore increasing the economic returns.     

Improvement of the quality and abatement of the biogenic amines of grass carp muscles by fermentation using mixed cultures

BACKGROUND: To improve the quality of processed grass carp (Ctenopharyngodon idellus) products and control the accumulation of hazardous substances therein, minced grass carp slices were salted for 6 h at room temperature and then inoculated with mixed starter cultures of Lactobacillus casei, Streptococcus lactis, Saccharomyces cerevisiae Hansen and Monascus anka and fermented for 12 h at 30 °C. The changes in some characteristics and biogenic amine contents of the fermented muscles were investigated. RESULTS: During the 12 h fermentation at 30 °C, muscles inoculated with mixed starter cultures showed a rapid decrease in pH from 6.0 to 5.1 and suppression of the growth of enterobacteria and pseudomonads. The fermented muscles exhibited better colour, appearance, flavour and overall acceptability than the control (P < 0.05). The changes in non‐protein nitrogen and free amino acid contents of the fermented muscles and in their sodium dodecyl sulfate polyacrylamide gel electrophoresis profiles indicated that severe hydrolysis of muscle proteins occurred during fermentation. The accumulation of biogenic amines in the muscles was efficiently reduced by fermentation with mixed starter cultures. CONCLUSION: Fermentation with mixed starter cultures of L. casei, S. lactis, S. cerevisiae Hansen and M. anka significantly improved the characteristics of grass carp muscles and controlled the accumulation of biogenic amines. Copyright © 2009 Society of Chemical Industry     

乳杆菌发酵剂对酸肉挥发性风味成分的影响

分别采用植物乳杆菌、清酒乳杆菌和类植物乳杆菌作为发酵剂对酸肉发酵过程中挥发性风味成分的影响。 电子鼻分析结果表明,酸肉的整体风味随发酵时间的增加差异显著;利用固相微萃取-气相色谱-质谱技术对酸肉发 酵过程中的挥发性风味物质进行检测,结果表明,酯类物质的相对含量显著增加,且增加的主要是乙酯类物质,发 酵结束时,添加植物乳杆菌、类植物乳杆菌和清酒乳杆菌组酸肉的乙酯类物质相对含量（56%、53%和60%）均显 著高于对照组（47%）,说明乳杆菌发酵剂的添加有利于酸肉中乙酯类物质的形成;通过Heatmap聚类分析发现, 发酵结束时,添加乳杆菌发酵剂的3 组酸肉整体风味比较接近,但与对照组差异较大,说明乳杆菌发酵剂的添加影 响了酸肉的风味品质。此外,发酵过程中添加发酵剂的酸肉中乳酸菌数量增加较快,肠杆菌数量显著降低,这保证 了酸肉的食用安全性。     

发酵方式对玉米粉品质和风味特性的影响

以未经发酵的玉米粉为对照,对自然发酵、植物乳杆菌、酿酒酵母菌及复配菌种（植物乳杆菌和酿酒酵母菌）发酵制得的玉米粉品质进行分析。结果表明：相比未发酵玉米粉,发酵后玉米粉中粗蛋白、粗脂肪、粗纤维和粗灰分含量显著降低（P<0.05）,总淀粉含量显著上升（P<0.05）;发酵使玉米粉的糊化温度显著升高（P<0.05）,自然发酵和复配菌种发酵后的玉米粉衰减值和回生值显著降低（P<0.05）,玉米粉的稳定性和抗老化性能提高;植物乳杆菌和复配菌种发酵对玉米粉的微观结构影响较大;酿酒酵母菌和复配菌种发酵产生的香气和代谢产物有效改善了发酵玉米粉的不良气味。通过不同发酵方式的对比得知,植物乳杆菌、酿酒酵母菌和复配菌种发酵可以将玉米粉自然发酵所需的13 d分别缩短至72、18 h和48 h,有效提高了生产效率。经复配菌种发酵后制得品质、风味且加工性能更加优良的玉米粉。     

Functional properties of selected starter cultures for sour maize bread

This paper focuses on the functional properties of maize sour-dough microflora selected and tested for their use as starter cultures for sour maize bread. Lactic acid bacteria and yeasts isolated from spontaneously fermented maize dough were selected based on dominance during fermentation and presence at the end of fermentation. Functional properties examined included acidification, leavening and production of some antimicrobial compounds in the fermenting matrix. The organisms previously identified as Lactobacillus plantarum, Lb. brevis, Lb. fermentum, Lb. acidophilus, Pediococcus acidilactici, Leuconostoc mesenteroides and Leuconostoc dextranicum and Saccharomyces cerevisiae were used singly and as mixed cultures in the fermentation (fermentation time: 12h at 28+/-2 degrees C) of maize meal (particle size >0.2mm). The pH fell from an initial value of 5.62-3.05 in maize meals fermented with Lb. plantarum; 4.37 in L. dextranicum+S. cerevisiae compared with the value for the control (no starter) of 4.54. Significant differences (P 相似文献   

Evaluation of lysine and methionine production in some Lactobacilli and yeasts from ogi

Lysine and methionine producing cultures of Lactobacillus and yeasts in batch fermentation of ogi were selected by growth in the presence of the analogues, S-2-aminoethyl]-L-cysteine (thialysine) and ethionine respectively. The study shows that 42.5% of the Lactobacillus and 83.3% of the yeast isolates tested were capable of lysine production while 25.0% of the Lactobacillus and 87.8% of the yeast isolates produced methionine. The lysine and methionine yields of Lactobacillus were significantly (P <0.01) higher than that of yeasts. The majority of the yeast isolates excreted most of the lysine and methionine produced. More lysine was produced than methionine in all tested isolates.     

不同乳酸菌发酵对甘薯淀粉加工浆液营养功能成分及感官特性的影响

选用植物乳杆菌（Lactobacillus plantarum,Lp）、保加利亚乳杆菌（Lactobacillus bulgaricus,Lb）、嗜热链球菌（Streptococcus thermophilus,St）、戊糖片球菌（Pediococcus pentosus,Pp）、干酪乳杆菌（Lactobacillus casei,Lc）及商业Lp（SZ）分别对甘薯淀粉加工浆液进行发酵,比较不同乳酸菌发酵对甘薯淀粉加工浆液营养功能成分（蛋白质、灰分、可溶性膳食纤维、不溶性膳食纤维、总膳食纤维、总酸、总糖、乳酸、短链脂肪酸、总酚、游离氨基酸）及感官特性（电子鼻、电子舌、气相色谱-质谱、感官评价）的影响。结果表明：6 种乳酸菌发酵后,浆液中蛋白质、糖类、可溶性膳食纤维、不溶性膳食纤维及总膳食纤维含量显著下降;不同乳酸菌均表现出良好的发酵性能,发酵后浆液pH值从6.62下降到3.67～3.88,总酸质量浓度由0.29 g/100 mL提高至2.69～3.67 g/100 mL,且乳酸及短链脂肪酸含量显著上升;Lb和Lc发酵显著提高了浆液中总酚含量,分别提升了18.44%和17.78%;在发酵液中共检出16 种游离氨基酸,其中必需游离氨基酸含量显著上升;气相色谱-质谱结果表明,乳酸菌发酵可有效提升甘薯淀粉加工浆液中风味物质的种类和含量,改善其风味和口感,其中Pp、St和SZ发酵浆液的总体感官品质最好。上述研究结果可为乳酸菌发酵应用于甘薯淀粉加工浆液制备饮料的研发奠定理论支撑。     

Effect of Select Parameters of the Sourdough Rye Fermentation on the Activity of Some Mixed Starter Cultures

The effect of select parameters (i.e., rye flour ash content, temperature, and dough yield) of the sourdough fermentation on the fermentation activity of different starter cultures (lactic acid bacteria Lactococcus lactis ssp. Lactis, Weissella confusa, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus helveticus, and yeast Kluyveromyces marxianus subsp. Marxianus) was determined. The major metabolic end products of fermentation (D, L-lactic acid, acetic acid, ethanol and glycerol) and the evolution of total phenolic content and folic acid during bread making were measured. Lactobacillus helveticus and Kluyveromyces marxianus allowed obtaining sourdoughs with the highest lactic acid/acetic acid ratios. The mixed starter culture with Lactococcus lactis and Saccharomyces cerevisiae generated the most important quantities of D/L lactic acid. The maximum values of ethanol concentration were obtained in case of the sourdoughs from whole rye flour fermented at lower temperature (30°C) with mixed starter cultures containing Sacchomyces cerevisiae. The fermentation process and type of starter culture are also tools to increase the bioactive compounds, enabling the increase of the phenolic content of the sourdough.     

Involvement of Lactic Acid Bacteria in the Fermentation of TEF (Eragrosfis tef), an Ethiopian Fermented Food

Tef injera, a pancake-like acidic food is prepared from fermented tef ( Eragrostis tef ), flour. A complex group of microorganisms is involved in the fermentation. Fermentation is initiated by members of the Enterobacteriaceae. Their activities during the first 18 hr of fermentation reduce the pfi of the dough to about 5.8. They are then succeeded by Leuconostoc mesenteroides and Streptococcus faecalis. As the pH is further reduced to about 4.7, Pediococcus cerevisiae, Lactobacillus brevis, Lactobacillus plantarum and Lactobacillus fermentum become the predominating flora and remain so until the fermentation is terminated at 72 hr. These lactic acid bacteria are responsible for the acidic characteristics of the dough. Yeasts only appear in significant numbers at a latter stage of the fermentation.     

发酵剂对泡萝卜品质的影响

为确定不同发酵剂对泡萝卜品质的影响,将6 种不同微生物群落组成的发酵剂接种泡萝卜7 d,分析发酵过程中基本理化指标、质构特性、亚硝酸盐、17 种氨基酸和有机酸含量的变化。结果表明,接种发酵剂2的泡萝卜品质最佳,在接种第4天即可达到成熟。发酵至第7天,发酵剂3接种泡萝卜硬度略高于其他组（P＞0.05）,且发酵过程中亚硝酸盐含量远低于国家限量卫生标准。发酵过程中,泡萝卜所含氨基酸、有机酸种类丰富,其中接种发酵剂2泡萝卜在发酵7 d甜味和鲜味氨基酸显著高于其他组（P＜0.05）,谷氨酸含量最高,为（0.18±0.01）mg/g,有机酸含量也显著高于其他组（P＜0.05）,给予泡萝卜良好的风味品质。综合分析,发酵剂2能为高品质泡萝卜专用发酵剂的开发提供理论依据。     

Identification of lactic acid bacteria isolated from kimchi and studies on their suitability for application as starter culture in the production of fermented sausages

The aim of the investigation was to identify strains of lactobacilli coming from kimchi with properties suitable for use as starter cultures in sausage fermentation. A total of 31 strains of lactobacilli were isolated from kimchi on the 4-6th day of fermentation at 20°C using MRS agar plates and identified on the basis of morphological, biochemical, and physiological characteristics. The isolates were identified as Leuconostoc mes.mes./dent (12.9%), Lactobacillus curvatus (9.7%), Lactobacillus brevis (35.5%), Lactobacillus sake (25.8%), and Lactobacillus plantarum (16.1%). Thus, 51.6% of the isolates were homo-fermentative or facultative hetero-fermentative bacteria and the rest (48.4%) were hetero-fermentative bacteria. Among them L. brevis, L. curvatus, L. plantarum, and L. sake were investigated for their growth profile and metabolism characteristics in the fluid (submerged) model-medium modified according to the special conditions of fermented sausages. Relatively good growth properties were found for L. brevis, L. plantarum, and L. sake with maximum numbers of 8.18, 8.51 and 8.17cfu/ml, respectively, whereas L. curvatus could not adapt to the special environmental conditions. Regarding souring properties, L. brevis showed little ability to decrease pH, whereas L. curvatus, L. plantarum, and L. sake showed relatively good acidifying properties. According to the results of glucose fermentation and its products, only L. plantarum exhibited homo-fermentative characteristics. As a result only L. plantarum among the isolates from kimchi had an ability to adapt to the complex environment of fermented sausage, which will thereby allow them to act as starter cultures and natural preservatives in sausage production.     

Ogi Quality of Sorghum Flour Dry-Milled from Fermented Sorghum Grains

Sorghum flour, dry-milled from fermented sorghum grains, and ogi samples were evaluated for starch and damaged starch contents, titratable acidity and amylograph pasting viscosity. Reduction in starch content due to fermentation resulted in a corresponding increase in titratable acidity. Fermented sorghum flour, dry-milled from grains steeped in souring water, had a titratable acidity of 0.77% and an index of gelatinization value of 285 B.U. while wet-milled ogi had corresponding values of 0.88% and 210 B.U., respectively. Quality parameters in the dry-milling of fermented grains for ogi manufacture re high-lighted.     

Effect of fermentation with mixed starter cultures on biogenic amines in bighead carp surimi

The effects of one group mixed starter cultures, combined with Lactobacillus casei, Streptococcus lactis, Saccharomyces cerevisiae Hansen, and Monascus anka, and a batch without starter as control on biogenic amines accumulation in the bighead carp surimi during fermentation were investigated. Determination of five different biogenic amines was carried out by reverse‐phase high‐performance liquid chromatography with UV detection. Results showed that mixed starter cultures decreased the pH quickly from initial pH value of 6.4 to 5.2, inhibited the growth of contaminant microorganisms, such as Enterobacteriaceae and Pseudomonas, present in the raw materials, and suppressed the accumulation of histamine, tyramines, spermine and spermidine. Fermentation inoculated with combination of Lactobacillus casei, Streptococcus lactis, Saccharomyces cerevisiae Hansen, and Monascus anka with negative‐decarboxylase activity may prevent biogenic amine formation in the fermented ssurimi and improve hygienic quality of fermented surimi.     

Headspace flavour compounds produced by yeasts and lactobacilli during fermentation of preferments and bread doughs.

Production of volatile flavour compounds during fermentation with pure cultures of Saccharomyces cerevisiae and Candida guilliermondii, Lactobacillus brevis and Lactobacillus plantarum have been investigated, using wheat doughs and several preferements as substrates. For yeast, preferments consisted of 10% (w/v) glucose, maltose and sucrose solutions, whereas for lactobacilli they consisted of supplemented and unsupplemented (3% and 10% (w/v)) glucose solutions, and a 10% (w/v) wheat flour slurry. Seven volatile compounds (acetaldehyde, acetone, ethyl acetate, ethanol, hexanal+isobutyl alcohol, and propanol) were detected when using yeasts. All these compounds, except propanol, appeared for all the substrates assayed, with ethanol as the predominant component. Generally, S. cerevisiae produced higher amounts of the different components than C. guilliermondii. Both yeasts produced larger amounts of volatile flavour compounds during fermentation in glucose and sucrose solutions than in maltose or wheat dough. In general the yeasts examined produced more flavour components than the lactobacilli. For the lactobacilli the highest number of volatile flavour compounds were observed for substrates containing flour.     

乳酸菌发酵对草鱼肉理化特性和蛋白质降解变化的影响

研究了乳酸片球菌、乳杆菌-Lo3、乳杆菌-B5407和清酒乳杆菌4种不同乳酸菌在发酵草鱼肉时鱼肉理化特性及蛋白质降解变化的规律和特征。结果表明:添加乳酸菌后,鱼肉pH值迅速由最初的6.25降至2d时的5.06～5.40,对照组则为5.98;接种发酵剂的草鱼肉的TBA和TVB-N值的上升较缓慢,整个发酵过程中显著低于对照组(P<0.05);腌制草鱼肉的蛋白质在发酵期发生了轻微的降解,游离氨基酸略有增加;贮藏期间游离氨基酸量显著增加,肌浆蛋白和肌原纤维蛋白均发生了强烈的水解,接菌组的蛋白降解显著多于对照组,其中,接种乳酸片球菌和乳杆菌-B5407组降解程度最大。     

The use of a starter culture in the fermentation of cassava for the production of "kivunde", a traditional Tanzanian food product

Three cassava fermentation methods (spontaneous fermentation, back-slopping and the use of starter culture) for the production of kivunde, executed in three trials at 30 degrees C, were compared in terms of cyanide level reduction, microbiology and product quality improvement. Among the isolates from spontaneously fermented cassava batches, four strains were selected on the basis of their enzymatic activities and acid production. All were identified as Lactobacillus plantarum and were used as starters in this study. Lowest residual cyanide levels were detected after 120 h fermentation time in samples fermented with the starter culture and were below the maximum value of 10 mg/kg recommended by the Codex/FAO for cassava flour. This finding seems to be related to the alpha-glucosidase activity of the inoculated strains of which API-zyme (Bio-Merieux) tests showed activities of between 20 and > or = 40 nmol/4 h. The total residual cyanide levels of the spontaneous and back-slopping fermentations at 96 h were respectively 43.5 and 47.7 mg/kg dry weight of cassava. Extension of the fermentation period to 5 days, lead to further substantial reduction in the residual cyanide level in both these processes, but not below the recommended maximum value as in the case of starter culture fermented products. The spontaneous and back-slopping fermented cassava showed signs of deterioration after 3 days of fermentation. There was a sharp drop of pH and an increase of titratable acidity for all three batches during the first 48 h followed by a slow rise of pH and drop in titratable acidity towards the end of fermentation. The samples fermented with the starter culture had a smooth texture and pleasant fruity aroma, as opposed to the course and dull appearance and more complex flavour of the samples of spontaneous and back-slopping batches. During fermentation with starter culture, Enterobacteriaceae and yeasts and moulds could not be isolated throughout the period of fermentation (detection limit: 10 colony forming units/g). The present findings indicate the suitability of these Lb. plantarum strains as starter cultures for cassava fermentation in the kivunde process. The paper highlights the potential for the improvement of a traditional African fermented food (kivunde) through the use of a starter culture.     

Biochemical characterization of lactic acid bacteria isolated from spontaneous fermentation of 'Almagro' eggplants

A total of 149 strains of lactic acid bacteria isolated from the spontaneous fermentation of 'Almagro' eggplants were characterized and identified. Of the isolates, 148 were determined as belonging to the genus Lactobacillus. A coccoid, gram-positive database-negative isolate was obtained in the early stages of fermentation. The Lactobacillus strains were divided into six groups based on sugar fermentation patterns and other physiological and morphological characteristics, and were identified as Lactobacillus plantarum biotype 1 (54.4%), Lactobacillus brevis biotype 2 (19.5%), Lactobacillus fermentum (9.4%), Lactobacillus brevis biotype 3 (5.4%), Lactobacillus pentosus (4.7%) and nine strains, which were not included in the previous species, were grouped as Lactobacillus spp. (6.0%). Fermentation was initiated by Lactobacillus brevis biotype 2 and Lactobacillus fermentum. During the fermentation Lactobacillus plantarum became the predominant species.     

Comparison of the expansion ability of fermented maize flour and cassava starch during baking

The modifications occurring during the fermentation (at 20 or 35 °C) and drying (under the sun or in an oven at 40 °C) of maize flour (ogi) and cassava starch along with their expansion ability during baking were characterised and compared. A high temperature accelerated the fermentation but favoured lactic acid synthesis for maize ogi and butyric acid for cassava starch. The increase in acidity was higher for maize, but dried maize ogi did not evidence any expansion ability whatever the experimental conditions. Cassava starch that had been fermented at 20 °C then sun‐dried presented the highest expansion ability. It was associated with low paste viscosities and high swelling and solubilisation values. When the fermentation was carried out at 35 °C, an annealing of cassava starch occurred that delayed starch gelatinisation and which could be involved in its lower baking expansion ability. © 2000 Society of Chemical Industry