Stability of Mannitol to Lactobacillus plantarum Degradation in Green Beans Fermented with Lactobacillus cellobiosus

Mannitol, in fermented green bean juice, was converted to lactic acid by Lactobacillus plantarum when the initial pH was raised to 3.9. However, at pH 3.5, mannitol was stable to anaerobic degradation by a 10⁶ CFU/ml inoculum of 19 strains of L. plantarum and four isolated homofermentative lactobacilli. Several strains were capable of limited mannitol degradation at an initial pH 3.7. Completely fermented beans were microbiologically stable for at least 6 months under anaerobic conditions at 27°C. It is possible that heterolactic acid-fermented vegetables are microbiologically stable provided fermentable sugars are removed and the pH is lowered below pH 3.7.     

Behaviour of Escherichia coli O157:H7 during the fermentation of Datta and Awaze, traditional Ethiopian fermented condiments, and during product storage at ambient and refrigeration temperatures

The survival of E. coli O157:H7 in fermenting foods and its prolonged survival in refrigerated fermented foods is documented. This prompted the study to evaluate survival of E. coli O157:H7 during the fermentation of Datta and Awaze, traditional Ethiopian condiments. Datta was prepared by wet milling a variety of spices along with green or red chilli and fermenting it by lactic acid bacteria. Awaze is a slurry made of red pepper, garlic and ginger to which various other spices were added and fermented by lactic acid bacteria (LAB) and yeasts. The Datta or Awaze slurry was separately inoculated with three strains of E. coli O157:H7 and the fermentation was allowed to proceed at ambient (20–25°C) temperatures for 7 days. When fermenting Datta or Awaze was initially inoculated at low inoculum level (3 log cfu/g), the test strains were not recovered after 24 h of fermentation. At higher initial inoculum level (6 log cfu/g), however, counts of the test strains in Datta at day 7 were less by about 1.5 log unit than the initial inoculum level. In fermenting Awaze, all test strains were completely eliminated in 7 days. The pH of the fermenting green and red Datta was reduced from 5.2 to 4.4 and that of Awaze dropped from 4.9 to 3.8 during this time. In another experiment, the fermented products were separately inoculated with the E. coli O157:H7 test strains at levels of 6 log cfu/g and incubated at ambient and refrigeration (4°C) temperatures for 7 days. In fermented Datta, two of the three strains were not recovered by enrichment after 6 days of storage at ambient temperatures. In fermented Awaze, all strains were below countable levels at day 5, but could still be recovered by enrichment at day 7. At refrigeration storage, counts of the test strains in Datta and Awaze products were <3 log cfu/g at day 7. The inhibition of our E. coli O157:H7 test strains in Datta and Awaze may be due to the antimicrobial activity of spices and other metabolites produced by LAB which may be effective at low pH.     

An assessment of the protein quality and vitamin b content of commonly used fermented products of legumes and millets

Fermented products of legumes, Bengal gram dhal (Cicer arietinum) and green gram dhal (Phaseolus aureus), and millets, bajra (Pennisetum typhoideum), jowar (Sorghum vulgare) and ragi (Eleucine coracana), were analysed for protein quality and vitamin B content. Fermentation reduced total crude protein by 6-8 % in the legume products and 4-6% in the millet products of bajra and ragi. No reduction in crude protein was observed in fermented jowar products. Temperature of batters increased considerably on fermentation, while pH decreased. The protein efficiency ratio (PER) and the true digestibility (TD) of legume products were not altered by fermentation, the biological value (BV) and net protein utilisation, (NPU), of Bengal gram dhokla improved significantly (P<0.05). The TD of fermented jowar increased significantly (P < 0.05) but not that of ragi, bajra and the legume products. BV and NPU of both jowar and ragi products increased significantly on fermentation (P<0.05) but not that of bajra. The thiamin and riboflavin contents of both the legume and millet products increased with increase in fermentation time. Steaming and cooking after fermentation reduced the thiamin and riboflavin content. However, fermentation after cooking of millet batters increased the levels of both vitamins markedly.     

Effect of Fermentation on Soluble Proteins and In Vitro Protein Digestibility of Sorghum, Green Gram and Sorghum-Green Gram Blends

Changes in pH, titratable acidity and proteins of meals of sorghum, green gram and sorghum-green gram blend (70:30, w/w) during fermentation at 25°C up to 5 days were monitored. The pH of fermenting meals decreased sharply with concomitant increase in the titratable acidity within 24 hr. The proteins, free amino acids, soluble proteins and in vitro protein digestibility markedly increased within 24 hr fermentation. Supplementation of green gram with sorghum decreased the acidity and improved the contents of crude protein, soluble proteins and free amino acids of fermented sorghum meal.     

鲊肉粉的加工工艺研究

以米粉和猪肉为主要原料,加入一定的辅料拌匀后,经自然发酵制作鲊肉粉。通过单因素试验和响应面试验优化鲊肉粉的发酵工艺条件。结果表明,鲊肉粉制作最佳工艺条件为：发酵温度30 ℃,发酵时间10 d,粉肉质量比2.5,米粉粒度20目,在此工艺条件下,发酵所得的鲊肉粉的pH值为（4.61±0.03）,感官评分为（92.24±1.16）分。通过响应面试验能很好的优化鲊肉粉的加工工艺,为鲊肉粉的工业化生产提供技术指导。     

Effect of Levilactobacillus brevis TISTR 860 and Lactiplantibacillus plantarum TISTR 951 on gamma-aminobutyric acid content in fermented rice flour and rice noodles (Kanomjeen)

This research aimed to reduce the fermentation time of fermented rice flour for fermented rice noodles (Kanomjeen) to 24 h by adding the initial starter cultures, which are Levilactobacillus brevis TISTR 860 (LB) and Lactiplantibacillus plantarum TISTR 951 (LP) alone in rice slurry to achieve the quality and high gamma-aminobutyric acid (GABA) content. The initial pH value of rice slurry was adjusted to 4.5 and enriched with 2% of monosodium glutamate (MSG) before fermentation. LP was able to produce lactic acid and reduced pH better than LB but produced GABA in less content. Expanding fermentation time induced decreasing in viscosity and whiteness of flour. Fermented rice noodles provided better tensile strength and elasticity. In conclusion, LB could produce GABA in the amount of 21.80 mg/100 g dry basis in 24 h with good quality.     

保加利亚乳杆菌ND02发酵乳清过程中的代谢特性

利用L. bulgaricus ND02对乳清进行发酵,研究其在发酵乳清过程中的代谢特性。通过分析乳清发酵过程中代谢物的动态变化规律,评估代谢产物对发酵乳清生理功效的影响。采用液质联用技术检测L. bulgaricus ND02发酵乳清过程中代谢物质,并采用多变量统计方法对差异代谢物进行筛选与分析。通过数据库比对鉴定得到异亮氨酸、多肽、甲基-D-吡喃半乳糖苷、油酸、琥珀酸、黄嘌呤和胞嘧啶腺苷酸等37个显著差异代谢物（P<0.05）。其中,半胱氨酸、Tyr-Trp、苯乳酸和胞嘧啶核苷酸等23个代谢物在发酵乳清中的相对含量显著增加（P<0.05）。 L. bulgaricus ND02在发酵乳清过程中产生了大量的氨基酸、寡肽、有机酸和核苷酸,这些物质赋予发酵乳清特殊的生理功效和营养价值。     

粳米鲊海椒的抗氧化活性及其对小鼠肝脏脂质过氧化作用的影响

粳米鲊海椒是以新鲜红辣椒经过破碎后与米粉等配料以一定比例混合并添加适量盐后厌氧发酵一定时间而成的一种中国西南地区地方特色的自然乳酸发酵辣椒制品。由于辣椒富含多酚,以及发酵过程中结合型多酚可能会释放等,因此研究了鲊海椒化学抗氧化活性及对肝脏脂质过氧化作用的影响。对不同发酵时段鲊海椒研究结果显示,总还原力和氧自由基吸收能力（oxygen radical absorbance capacity,ORAC）在发酵15 d后即达到较高水平,其峰值分别出现在发酵15 d和发酵60 d。进一步抗氧化活性分析显示,发酵15 d样品清除1,1-二苯基-2-三硝基苯肼自由基的能力强于发酵60 d样品,但无显著差异（P＞0.05）。细胞抗氧化作用研究显示,发酵60 d样品羰基含量显著低于对照＋偶氮二异丁脒盐酸盐组（P＜0.05）,对牛血清白蛋白氧化抑制率是发酵15 d样品的2.38 倍;红细胞溶血延迟时间随处理质量浓度增加快速下降,发酵15 d样品下降速率快于发酵60 d样品,质量浓度为0.5 mg/mL时溶血延迟时间相对最长,发酵15 d和60 d样品差异不显著（P＞0.5）;发酵60 d样品对肝脏脂质过氧化的抑制作用显著强于发酵15 d样品（P＜0.05）,表明延长发酵时间有利于提升细胞抗氧化能力。相关性分析结果显示,不能用多酚含量判断样品的细胞抗氧化作用。本研究表明不能单独用化学抗氧化方法评价抗氧化能力,通过建立细胞模型综合评价食物的抗氧化性能更客观判断食物的抗氧化能力。     

FERMENTED COWPEA FLOUR: PRODUCTION AND CHARACTERIZATION OF SELECTED PHYSICO-CHEMICAL PROPERTIES

A simplified solid-substrate fermentation and milling process for preparing flour from nondecorticated cowpeas (cv. White Acre) was developed. Yield of fermented flours compared to starting substrate was about 73%. Total solids loss (ca. 21–23%) was due to soaking (6%), boiling (11%), fermentation (2–4%) and grinding (2%). Moisture loss during drying was approximately 5%. The pH of fermented flours ranged from 6.4 to 6.9. Fermented flours had less packed density but greater unpacked density than the control flour. About 41–44% of flour particles passed through a 0.297-mm sieve; 65–72% of these particles were in the exclusion range of 0.037–0.074 mm. An increase in color saturation of fermented flours was due mainly to increased b* (yellowness) values. Fermented flours contained about 28% protein, 1.8–2.0% fat, 4.9–6.2% moisture, 2.7% ash, and 61–63% total carbohydrate.     

Effect of some traditional processing operations on the functional properties of African breadfruit seed (Treculia africana) flour

The effect of germination, fermentation, roasting and defatting on the proximate composition, water absorption capacity (WAC), oil absorption capacity (OAC), foaming capacity (FC), foaming stability (FS), emulsion capacity (EC), emulsion stability (ES), packed bulk density (PBD), least gelation concentration (LGC) and protein solubility (PS) of breadfruit seed flour (BSF) was investigated. WAC, OAC, FC, EC, PBD and LGC obtained are 190-380%; 130.3-200.5%; 2.3-60.4%; 12.4-52.9%; 0.4-0.6 g/ml; 6-12% (w/v) and 200-420%; 176.4-320.6; 4.2-70.8%; 20.2-60.4%; 0.5-0.7 g/ml; 0.5-0.8% (w/v) in the full fat and defatted flours respectively. Foams were more stable in the untreated; least in fermented and roasted samples. Defatting improved the FC, FS and EC; roasting and fermentation reduced EC of full fat BSF; Processing and defatting had no effect on the PBD; roasting and germination increased LGC while defatting and fermentation reduced it. Full fat flours had the lowest PS at pH 4 and the highest at pH 8. Fermented full fat BS flour had the highest PS at pH 5 and 8. Defatted germinated, raw dried and roasted BSF had lowest PS at pH 4; PS of fermented BSF is lowest at pH 3 and highest at pH 2.     

Effect of Liquid Smoke on the Growth of Lactic Acid Starter Cultures used to Manufacture Fermented Sausage

Fermented sausage was manufactured using a commercial lactic acid starter culture and varying levels of liquid smoke. Samples were taken during the 24 hr fermentation period and the lactic bacterial count, pH and titratable acidity determined. Final pH values, titratable acidity and lactic bacterial counts were not affected by recommended use levels of liquid smoke, although exponential growth was delayed. Growth studies in a broth medium containing liquid smoke suggest that liquid smoke has the potential for inhibiting the lactic starter cultures used to make fermented sausage.     

Evaluation of the effect of supplementing fermented milk with quinoa flour on probiotic activity

In this work, we investigated the effect of supplementing fermented milk with quinoa flour as an option to increase probiotic activity during fermented milk production and storage. Fermented milk products were produced with increasing concentrations of quinoa flour (0, 1, 2, or 3 g/100 g) and submitted to the following analyses at 1, 14, and 28 d of refrigerated storage: postacidification, bacterial viability, resistance of probiotics to simulated gastrointestinal (GI) conditions, and adhesion of probiotics to Caco-2 cells in vitro. The kinetics of acidification were measured during the fermentation process. The time to reach maximum acidification rate, time to reach pH 5.0, and time to reach pH 4.6 (end of fermentation) were similar for all treatments. Adding quinoa flour had no effect on fermentation time; however, it did contribute to postacidification of the fermented milk during storage. Quinoa flour did not affect counts of Bifidobacterium animalis ssp. lactis BB-12 or Lactobacillus acidophilus La-5 during storage, it did not protect the probiotic strains during simulated GI transit, and it did not have a positive effect on the adhesion of probiotic bacteria to Caco-2 cells in vitro. Additionally, the adhesion of strains to Caco-2 cells decreased during refrigerated storage of fermented milk. Although the addition of up to 3% quinoa flour had a neutral effect on probiotic activity, its incorporation to fermented milk can be recommended because it is an ingredient with high nutritive value, which may increase the appeal of the product to consumers.     

THE LACTIC ACID FERMENTATION OF THREE DIFFERENT GRAPE LEAVES GROWN IN TURKEY

Leaves of three different cultivars of Vitis vinifera L., Ekşikara, Hesapali and Siyah pekmezlik were fermented in 10% brine and 10% brine + 1% citric acid concentration for 5 weeks. Percent dry matter, average weight, protein and dimethyl sulfide content of fresh leaves were determined. During the fermentation time, chemical properties of brine (titratable acidity, pH, salt content) were determined at certain intervals. Fresh leaves of Ekşikara had the highest amount of dry matter (31.69%), followed by Siyah pekmezlik (27.89%) and Hesapali (25.36%).The protein content of fresh leaves decreased approximately 50% as a result of the fermentation. Fermented Hesapali leaves had the highest (2,955 kcal/100 g), while Siyah pekmezlik leaves had the lowest (2,384 kcal/100 g) energy values. Ekşikara leaves in 10% brine + 1% citric acid had the lowest pH value (2.09), while Siyah pekmezlik had the highest pH value (2.57) on the fifth week of the fermentation. The highest titratable acidity was measured in Hesapali (10% brine + 1% citric acid). Hesapali leaves in both types of brine showed the highest taste scores, while Ekşikara leaves were preferred for their more acceptable odor. Siyah pekmezlik leaves are not recommended for brining as the fermented leaves of this cultivar obtained the lowest sensory scores.     

Angiotensin‐converting enzyme inhibition,antioxidant activity and cytotoxicity of bioactive peptides from fermented bovine colostrum

Fermented bovine colostrum rich in bioactive peptides was obtained using Candida lipolytica strains in co‐culture with kefir grains. During fermentation, the pH and total titratable acidity of the product were daily measured. The hydrolysis degree and the electrophoretic pattern of water‐soluble extracts (WSE) of fermented colostrum were analysed. Fractions enriched in peptides with a molecular weight lower than 10 kDa were separated by ultracentrifugation. They showed better modulation of angiotensin‐converting enzyme (ACE) inhibition and cell proliferation, but lower radical scavenging capacity, compared to corresponding WSE.     

Effect of Aqueous Extract of the Seaweed Gracilaria domingensis on the Physicochemical,Microbiological, and Textural Features of Fermented Milks

The effects of the Gracilaria domingensis seaweed aqueous extract in comparison with gelatin on the physicochemical, microbial, and textural characteristics of fermented milks processed with the mixed culture SAB 440 A, composed of Streptococcus thermophilus, Lactobacillus acidophilus, and Bifidobacterium animalis ssp. lactis, were investigated. The addition of G. domingensis aqueous extract did not affect pH, titratable acidity, and microbial viability of fermented milks when compared with the control (with no texture modifier) and the products with added gelatin. Fermented milk with added the seaweed aqueous extract showed firmness, consistency, cohesiveness, and viscosity index at least 10% higher than those observed for the control product (P < 0.05). At 4 h of fermentation, the fermented milks with only G. domingensis extract showed a texture comparable to that observed for products containing only gelatin. At 5 h of fermentation, firmness and consistency increased significantly (P < 0.05) in products with only seaweed extract added, a behavior not observed in products with the full amount of gelatin, probably due to the differences between the interactions of these ingredients with casein during the development of the gel network throughout the acidification of milk. The G. domingensis aqueous extract appears as a promising gelatin alternative to be used as texture modifier in fermented milks and related dairy products.     

CHARACTERIZATION OF FERMENTED CASSAVA STARCHES

Fermented and nonfermented cassava (Manihot utilissima Pohl) starches from Colombia and Brazil were studied. The DSC thermograms obtained at high water contents (water:starch 3.1 to 4.2) showed that starch fermentation decreased both the temperature of gelatinization (Tmax) and that of final gelatinization. No significant differences were found between the enthalpies of gelatinization of fermented and non-fermented starches. Differences in ΔH corresponding to the first endothermic transition of fermented and nonfermented samples were detected at low water contents (water:starch 1.0 to 0.4). Pastes obtained with nonfermented starches were more viscous than those corresponding to fermented samples. This behavior could be related to the greater solubility of the fermented samples, leading to a smaller size of hydrated granules.     

Inhibitory power of kefir: the role of organic acids

Milk and MRS broth fermented with kefir grains from different households were examined for inhibitory activity toward gram-negative and gram-positive strains. Fermented milk obtained with 10 g per 100 ml of inoculum (final pH 3.32 to 4.25) and MRS broth fermented with 1 and 10 g per 100 ml of inocula (final pH 4.18 to 5.25) had inhibitory power demonstrated by spot test and agar well diffusion assay. This inhibitory effect could be assigned to the undissociated form of lactic and acetic acid produced during the fermentation process. Kefir supernatants inhibited the growth of Escherichia coli 3 in nutrient broth at 37 degrees C for 24 h. However, supernatants of yogurt or milk artificially acidified with lactic and acetic acids allowed the growth of E. coli 3 in the same conditions. A bacteriostatic effect of milk fermented with kefir grains over E. coli 3 was also demonstrated.     

自然与乳酸菌强化发酵过程中红酸汤品质变化

利用红酸汤为原料,以总酸、亚硝酸盐、pH、还原糖、可溶性固形物、水分、抗坏血酸为检测指标,分析不同发酵时间自然与乳酸菌强化发酵的红酸汤品质变化规律。结果表明,在整个发酵过程中,自然与乳酸菌强化发酵的红酸汤中还原糖、抗坏血酸、可溶性固形物均呈逐渐下降的趋势;总酸含量和pH均在第6天达到峰值,分别为10.11 g/kg和3.04与10.26 g/kg和2.84;水分含量在第6天达到最低,分别为84.83%与84.18%;亚硝酸盐含量最高分别为0.052 2 mg/kg与0.030 4 mg/kg,未超标。因此,与自然发酵相比,乳酸菌强化发酵明显减少亚硝酸盐含量,缩短了红酸汤发酵周期,但自然发酵红酸汤品质更好。     

AMINO ACID CHANGES IN THE KOREAN TRADITIONAL FERMENTATION PROCESS FOR BLUE MUSSEL, MYTILUS EDULIS

The effect of fermentation period on biochemical composition of fermented blue mussel was investigated in three fermentation stages. Fermented blue mussel sauces (FBMSs) were prepared with 25% NaCl (w/w) at 20C for different fermentation periods. The FBMSs were desalted below 1% (w/w) by an electrodialyzer. It was observed that content of protein increased and carbohydrate decreased throughout the fermentation. In addition, the changes of free amino acids were investigated, and the levels of amino acids such as glycine, alanine, proline, aspartic acid and glutamic acid were higher, which may be important for the taste of fish and shellfish sauce.     

利用高通量测序分析云南豆豉中细菌群落多样性

发酵食品是人类饮食的重要组成之一,其中豆豉风味独特,富含多种生理活性物质。微生物在食品发酵过程中起着极为重要的作用。作者选择云南豆豉为研究对象,使用焦磷酸高通量测序,可以全面地分析豆豉中的细菌群落,能够得到其中稀少群落(rare biosphere)的信息。乳酸杆菌是丰度最高的细菌,占总序列数的72%,在豆豉发酵中起重要作用;芽孢杆菌也是重要的细菌,占序列总数的10%。此外,还发现了属于人类致病菌(Shigella flexneri)和植物病原菌(Erwinia persicina)的序列,显示出传统方法制作的豆豉中存在着食品安全隐患。