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.     

Characterization of Lactobacillus strains and monitoring by RAPD-PCR in controlled fermentations of "Almagro" eggplants

The characterization of 23 Lactobacillus strains was performed. The strains were assayed for biogenic amine-forming capacity, hydrogen peroxide production, pectin esterase, cellulase and polygalacturonase production, growth rate, acidifying capacity and salt tolerance. Three strains were selected which belonged to the species, Lactobacillus brevis, Lactobacillus plantarum and Lactobacillus fermentum. Different starter cultures prepared as combinations of these three strains were assayed in pilot scale fermentations and Randomly Amplified Polymorphic DNA (RAPD) analysis, using a previously selected random primer, was applied for monitoring the inoculated strains. The course of fermentations was similar in all batches but sensorial analysis of eggplants fermented using a mixed culture of the three strains displayed the best results, and no differences were obtained when compared with commercial eggplants.     

直投式功能菌剂发酵佛手瓜腌菜工艺优化研究

目的：对直投式功能菌剂发酵生产佛手瓜腌菜的工艺进行优化研究。方法：研究直投式佛手瓜腌制在不同直投式功能菌剂添加量、食盐添加量、发酵温度、发酵时间等条件下,佛手瓜发酵时腌菜液中总酸含量的动态变化。根据动态变化和正交试验法确定直投式功能菌剂发酵腌菜的最佳条件。结果：直投式功能菌剂发酵腌菜的最佳条件为：蔗糖添加量3%、直投式功能菌剂添加量0.1%、发酵温度30℃、食盐添加量7%、发酵时间4d,此时产酸量达0.73g/100g。结论：采用直投式功能菌剂生产发酵佛手瓜腌菜,发酵周期短,发酵效果好。     

Evaluation of malolactic-deficient strains of Lactobacillus plantarum for use in cucumber fermentations

In the fermentation of cucumbers, naturally occurring strains of Lactobacillus plantarum decarboxylate malic acid (MDC⁺) to form lactic acid and CO₂. Since CO₂ buildup in the brine contributes to bloater damage of the cucumbers, it is desirable to have strains of L. plantarum that do not decarboxylate malic acid (MDC^-1). Two MDC^- mutants, obtained by N-methyl-N′-nitro-N-nitrosoguanidine mutagenesis of different MDC⁺ strains, and their parent strains of L. plantarum wre evaluated in laboratory fermentations of filter-sterilized cucumber juice and of whole cucumbers as to growth rate, end-products, residual malic acid, and competitiveness with the natural flora. Effects of temperature (15 to 40°C) and NaCl concentration (0-6%) on growth in cucumber juice were determined. One MDC^-1 strain, designated MOP3-M6, was selected for further development because of its relative dominance in cucumber ferementations, high residual malic acid concentration after fermentation and greater salt tolerance as compared to its closest rival mutant culture. Growth lag and generation times averaged 1·6 and 1·2 times greater, respectively, for the MOP3-M6 mutant than its parent. However, this mutant may still have application as a starter culture for cucumber fermentation, particularly under relatively aseptic conditions.     

直投式发酵剂生产四川泡菜的研究

通过分析接入乳酸菌直投式发酵剂和自然发酵四川泡菜发酵过程中亚硝酸盐含量、乳酸菌菌数和产品品质的动态变化,确定直投式菌剂发酵泡菜时的菌粉添加量和食盐用量。结果表明:添加4%食盐,接入0.04%直投式发酵剂,室温25℃,发酵7d后制得的泡菜酸甜适口,色泽好。添加到直投式发酵剂终产品中的亚硝酸盐含量显著低于自然发酵组,仅为2.11μg/mL,且其乳酸菌菌数远高于自然发酵组,肠膜明串珠菌和植物乳杆菌菌数分别达到6.42×107cfu/mL和3.13×107cfu/mL。     

Green olive fermentation using spontaneous and <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> cultures

The aim of this work was to evaluate the performance of spontaneous and Lactobacillus cultures in Spanish style fermentation of olive fruits. A fermentation with Lactobacillus plantarum ATCC 8014 was carried out for comparison. Fermentation was performed at room temperature during 120 days in two different concentrations of NaCl (2.4–13.6 % w/v) and sucrose (0–0.82 % w/v) in the brines. The pH, chlorides, lactic acid, reducing sugar and lactic bacteria in selective medium were investigated during the olive fermentation. After 120 days of fermentation, the formulation with 12 % NaCl in the brine hampered the growth of lactic bacteria, avoiding the consumption of reducing sugars. However, low salt concentrations (≤4 %) promoted a decrease in pH, an increase of the lactic acid and the growth of lactic bacteria, providing best environmentally suitable for the fermentation process. Whereas using concentrations of 12 % NaCl and 0.7 % sucrose showed better chemical conditions, ensuring the safety of the product produced. Multivariate analysis showed that the olives with both cultures were in close relation to lactic acid and reducing sugar and different from lactic bacteria.     

Pickling and storage of caperberries (Capparis spp.)

 Caperberries (0.7–1.9 cm diameter), collected in June 1996, were pickled for 1 month in 5% and 10% brine. Some physical, chemical and microbiological analyses were made during their fermentation and storage. While lactic acid bacteria (LAB) increased during fermentation in 5% brine, they did not increase after 15 days in 10% brine. In some cases, total bacterial (TB) growth decreased. In both brines, yeasts/moulds and coliforms (except for 5% brine on day 15) were not present after 15 and 20 days, respectively. For both caper species, the most suitable salt concentration, for LAB activity was 5–10% NaCl, and the best length of fermentation with respect to product colour, flavour, acidity, pH and LAB activity in brine was 20–25 days. The texture was maintained well during storage. Acidity and pH were markedly affected by the concentration of brine. The quality of all samples was maintained with a 15% concentration of old or fresh brine during storage. The colour of the samples, especially those of C. ovata, stored with old brine was darker that of fresh berries. As no "off" flavour was observed, it was concluded that pickled caper berries can be stored in fresh brine with a 15% NaCl concentration.     

Effect of brine replacement and salt concentration on the fermentation of naturally black olives

This study was undertaken to modify the traditional fermentation of naturally black olives in order to obtain higher quality black table olives. After holding olives in tap water or low salt brine prior to fermentation, acidification of the cover brine and fermentation at two different salt concentrations (6 and 14 g/ 100 ml NaCl) were applied to Gemlik variety olives in three batches. Fermentations were monitored using physical, chemical and microbiological analyses and effects of the above changes to fermentation were investigated. Yeasts were the predominant microorganisms in all of the batches. Growth enhancement of lactic acid bacteria by brine replacement occurred in the fermentation with 6 g/ 100 ml NaCl cover brine but not with 14 g/100 ml NaCl brine. The highest level of titratable acidity (0.59 g/100 ml) formed during fermentation with 6 g/100 ml NaCl brine followed by fermentation with 6 g/100 ml NaCl brine (0.43 g/100 ml) where the brine was replaced after 48 days. The lowest level of titratable acidity (0.36 g/100 ml) was formed using a high salt brine. Reducing sugars were consumed effectively by microorganisms in all the batches and residual levels in the brines were 0.05–0.1 g/100 g ml. NaCl contents of the final products were 5.20 g/ 100 g (olives with high salt brine) and 3.27–3.58 g/100 g (olives with low salt brine). Moisture contents of the processed olives were in the range 49.58–50.79 g/ 100 g. The water activity (a_w) value of olives fermented with the high salt brine was found to be 0.947 while a_w values of olives fermented with the low salt brine were 0.962–0.964. Protein content of the olives ranged between 1.76–1.95 g/100 g and the ash contents were found to be 2.41–2.81 g/100 g in olives with low salt brine and 4.70 g/100 g in olives with high salt brine. According to sensory evaluations of the final products, no differences between the treatments were found (P > 0.05).     

不同盐质量分数泡白菜发酵过程中乳酸菌群落结构的变化

设计3种不同盐质量分数的泡白菜,包括低盐(2%)、中盐(5%)、高盐(8%),利用可培养方法结合多种分子生物学手段研究其发酵过程中乳酸菌的群落结构。结果表明:盐质量分数越低,乳酸菌增长速率越快。本研究从3种不同盐质量分数泡白菜发酵过程中分离筛选得到了563株乳酸菌,并采用16S rDNA测序、多重聚合酶链式反应、聚合酶链反应-限制性片段长度多态性、API 50CH等多种不同的鉴定方法进行鉴定,鉴定结果表明这563株乳酸菌属于5个属11个种。结果表明,低盐泡白菜发酵前期的优势菌为Lactococcus lactis、Lactobacillus pentosus和Leuconostoc,发酵后期则由Lactobacillus pentosus主导;中高盐泡白菜发酵前期由Lactobacillus pentosus和Weissella主导,发酵后期主要由Lactobacillus pentosus完成。     

两株乳酸菌的发酵特性及在发酵驴肉肠中的应用

戊糖片球菌(Pediococcus pentosaceus,P.p)与干酪乳杆菌(Lactobacillus casei,L.c)常作为发酵剂应用于发酵香肠的制作,但能否作为驴肉香肠的发酵剂以及发酵剂的配比、菌液浓度等一直没有明确的指标限制。本研究对P.p、L.c的生长曲线、产酸率、耐盐性等特性进行研究分析并进行混菌培养试验,两种乳酸菌均符合发酵肉制品发酵剂的要求并可作为混合发酵剂。将发酵剂不同配比、菌液浓度、添加量等进行单因素试验,pH和感官品评作为评价指标进行四因素三水平的正交试验,得到在当前加工条件下较优的发酵条件:混合乳酸菌发酵剂菌种配比为L.c:P.p=1:1,菌种菌液浓度1×106 CFU/mL,发酵剂添加量1%,发酵温度35℃,发酵时间20 h,此条件下发酵驴肉肠色泽呈枣红色,pH为4.83,符合良好发酵香肠的感官标准。     

Contribution of starter culture to the sensory characteristics of fermented Almagro eggplants

Trial fermentations were performed using three experimental starter cultures with a view to selecting the most appropriate starter for use in the manufacture of Almagro eggplants. The lactic acid bacterial strains used in the starters had previously been isolated from spontaneous fermentations. The combined action of the obligate heterofermentative species Lactobacillus brevis and the facultative heterofermentative species L. plantarum yielded Almagro eggplants with sensory properties preferred by panelists. Conversely, another obligate heterofermentative species, namely, L. fermentum, present in certain starter formulations tested, appeared to encounter difficulty growing during fermentation and exerted little influence on the sensory characteristics of the eggplants produced.     

Use of selected autochthonous lactic acid bacteria for Spanish-style table olive fermentation

The present work presents a successful attempt to achieve an enhanced and more predictable fermentation process in Spanish-style green olive technology by selection and use of autochthonous starter cultures. During the first phase of this work, two Spanish-like fermentations of green table olives of cultivar (cv) "Nocellara del Belice", coming from irrigated and not irrigated fields, were monitored, in order to highlight the best agricultural conditions for drupe production and to isolate lactic acid bacteria strains with relevant technological properties. Among 88 identified isolates, one Lactobacillus pentosus strain showed remarkable biochemical features and high acidification rate in synthetic brine. In the second phase, the selected strain was used as starter culture in three different trials to establish the best conditions for its use. Microbial counting, as well as starter tracking by M13 RAPD-PCR, reflected the optimal adaptation of the strain to the environment. Spontaneous fermentation needed a 14-day long lag phase to reach the same population as the inoculated trials. Moreover, sensory traits of table olives obtained with adjunct culture showed better characteristics compared to those processed in the other trials, in particular concerning the presence of off-odours.     

Pickling and storage of caperberries (Capparis spp.)

Caperberries (0.7–1.9?cm diameter), collected in June 1996, were pickled for 1 month in 5% and 10% brine. Some physical, chemical and microbiological analyses were made during their fermentation and storage. While lactic acid bacteria (LAB) increased during fermentation in 5% brine, they did not increase after 15 days in 10% brine. In some cases, total bacterial (TB) growth decreased. In both brines, yeasts/moulds and coliforms (except for 5% brine on day 15) were not present after 15 and 20 days, respectively. For both caper species, the most suitable salt concentration, for LAB activity was 5–10% NaCl, and the best length of fermentation with respect to product colour, flavour, acidity, pH and LAB activity in brine was 20–25 days. The texture was maintained well during storage. Acidity and pH were markedly affected by the concentration of brine. The quality of all samples was maintained with a 15% concentration of old or fresh brine during storage. The colour of the samples, especially those of C. ovata, stored with old brine was darker that of fresh berries. As no "off" flavour was observed, it was concluded that pickled caper berries can be stored in fresh brine with a 15% NaCl concentration.     

Olive Fermentation and Processing: Scientific and Technological Challenges

ABSTRACT: The 3 main commercial table olive preparations are the Spanish-style green olives, the Greek-style naturally black olives, and the Californian-style black ripe olives. In all cases, fruits undergo fermentation in brine solution, which preserves them and increases palatability. Lactic acid bacteria dominate in brines of green olives, while mainly fermentative yeasts are found in brines of black ones. The fermentation is spontaneous and begins as soon as olives are put into brine. Research on table olives has been going on for 100 years, but many questions remain. Previous work has focused on the efficient utilization of starter cultures in order to control the fermentation, to guarantee the absence of spoilage, and to govern the relationship between olive flavor and microorganisms. Nowadays, there is concern over environmental problems that the fermentation solutions represent, in particular their high NaCl content. Fermentation or simply storing olives in water without salt presents some problems. The high concentration of sodium benzoate used for storing black ripe olives by the American industries is not advisable for European processes due to the residual amount of preservative in the final product. Fermentation of green olive wash waters, in order to obtain valuable products, is being pursued, but polymeric inhibitors are problematic and undesirable microorganisms grow. The consumption of organic foods is increasing and black olives fit the definition since they are processed without chemical treatment. However, the hydrolysis of the bitter compound oleuropein, either by microorganisms or acids, needs to be studied.     

响应面法优化海带酱的米曲霉和黑曲霉发酵工艺

为研究海带酱的最佳发酵工艺,在考察湿海带与湿黄豆比例、米曲霉与黑曲霉比例、盐浓度和盐水添加量等单因素对海带酱氨基态氮影响的基础上,采用响应面法对海带酱的米曲霉和黑曲霉发酵工艺进行优化。结果表明,海带酱的最佳发酵条件为:湿海带与湿黄豆比例为3:1,米曲霉与黑曲霉比例为2:1,盐浓度为14.5%,盐水添加量为77%,该条件下海带酱中氨基态氮值达到最高,为0.76%±0.04%,与理论预测值基本一致。这表明使用最佳发酵条件制作海带酱,可提高氨基态氮含量,增强海带酱的鲜味。同时,该海带酱营养成分为:能量171.33±1.15 kJ/100 g,蛋白质3.22±0.04 g/100 g,脂肪1.92±0.03 g/100 g,碳水化合物5.68±0.06 g/100 g,钠2633.00±1.00 mg/100 g;其中,氨基态氮含量符合GB/T 24399-2009《黄豆酱》标准。本研究可为发酵酱制品的进一步开发与利用提供一定的技术指导。     

Screening of commercial meat starter cultures at low pH and in the presence of bile salts for potential probiotic use

The survival of lactic acid bacterial strains from eight meat starter cultures under conditions similar to those in the gastrointestinal tract was determined. The conditions in stomach were simulated by using pH 1-5 phosphate-buffered saline. The conditions in small intestine were simulated by using MRS broth over a pH range 4-7 and two bile salt concentrations (0.15% and 0.30%). The survival capacity at pH 3 was strain dependent. 0.30% bile salts were critical for screening bile salt tolerant strains at pH 6. Strains of Lactobacillus sake (RM10) and Pediococcus acidilactici (P2) had the best survival capacities under acidic conditions and at the higher concentration of bile salts.     

Effect of freezing on the spontaneous fermentation and sensory attributes of Almagro eggplants

A study of the physico-chemical and microbiological processes taking place during the spontaneous fermentation of eggplant fruits that had been frozen after blanching revealed a delay in the onset of the active fermentation stage, which has been ascribed to the adverse effect of the freezing temperature employed on the lactic acid bacteria involved in fermentation. The species most affected by freezing were L. fermentum and L. brevis biotype 2. Despite this finding, the pattern of fermentation was similar to the fermentation process in unfrozen eggplants. Freezing of the fruits did not significantly affect the sensory acceptability of the product and, in fact, in some cases, Almagro eggplants made from frozen fruits were preferred to commercially manufactured products.     

THERMAL AND RHEOLOGICAL PROPERTIES OF BRINE FROM FERMENTED AND SULFITE‐PRESERVED CUCUMBERS1

Pickling cucumbers may be temporarily preserved by fermentation in brine (6–8% NaCl) or without fermentation in salt‐free, sulfite solution (300 ppm sulfite, pH 3.5). Brines obtained from preservation processes are often discarded. Due to environmental concerns, there is increasing consideration for further use of the brine solutions by recycling for use in bulk storage or filtration and incorporation into finished products. Thermal and rheological properties are fundamental to the reuse of the brine. The effect of temperature was determined on the rheological (5–45C) and thermal properties (5–75C) of brine. The properties of the brine samples were found to be significantly different (P < 0.05) from each other and from water. Salt content was the most important factor affecting the thermal and rheological properties of brine. At the same conditions, the values of the properties (thermal conductivity, specific heat, and thermal diffusivity, viscosity) were about 5 to 23% less than the corresponding values for water.     

Production of tyramine in "moromi" mash during soy sauce fermentation

The concentrations of 7 non-volatile amines, tyramine (Tym), histamine (Him), phenethylamine (Phm), putrescine (Put), cadaverine (Cad), spermidine (Spd) and spermine (Spm) in the liquid part of "moromi" mash during soy sauce fermentation were studied. These amines, except for him and Cad, were detected during fermentation by the conventional production method in the laboratory. Put and Spd were detected at the beginning, and Tym, Phm and Spm appeared later; these 5 amines increased gradually during the fermentation. Put, Spd, Spm and Cad were present in the raw starting material for soy sauce; thus, Tym and Phm were produced by the fermentation. When "moromi" mash was added to liquid medium and cultivated, Tym was detected in some "moromi" mash and the other amines were not detected. Tym-producing bacterial strains were isolated from the liquid culture media of Tym-positive "moromi" mash. The Tym-producing strain was a gram-positive coccus. The conditions for production of amines by Tym-producing bacterial strains were examined. These strains grew and produced tyramine under various conditions, which may occur during soy sauce fermentation. Namely, Tym was produced at pH 5-10, at salt concentrations of less than 8%, under either aerobic or anaerobic conditions. During soy sauce fermentation, it is assumed that Tym would be produced by these strains during the early stages of soy sauce aging within a short period when the salt concentration and pH conditions are optimal for growth. Based on the bacteriological properties, the strains were identified as Enterococcus faecium. With the exception of Phm and Him, which did not exist in the starting raw material, non-volatile amines (including Put, Cad, Spd and Spm) were not produced and microorganisms producing them are not believed to be present during "moromi" fermentation.     

Induced lactic acid fermentation of untreated green olives of the Conservolea cultivar by Lactobacillus pentosus

Inoculation of untreated green olives of the Conservolea cultivar (Olea europea media rotunda) with a commercial strain of Lactobacillus pentosus with/without glucose supplement was studied. Despite an initial loss in viability of 0.5 log cycles on average, due to lack of adaptation of the starter to the saline environment of the brine, cultures grew well and initiated an accelerated fermentation process. Inoculation reduced the survival period of Enterobacteriaceae, and consequently potential spoilage, and caused a quicker acidification of brines and decrease in pH compared with control uninoculated processes. The diffusion of phenolic compounds was slow, hindered by the epidermis of the fruits, and had no effect on the growth of the starter. HPLC analysis revealed that lactic and acetic acids were among the end‐products during the fermentation of green olives. Citric, tartaric and malic acids were also detected but at much lower concentrations. Results obtained from this work can be applied directly to industry for the effective use of starter cultures on natural fermentation processes of green olives without prior lye treatment. © 2003 Society of Chemical Industry