Comparative study of the inhibitory effects of wine polyphenols on the growth of enological lactic acid bacteria

This paper reports a comparative study of the inhibitory potential of 18 phenolic compounds, including hydroxybenzoic acids and their derivatives, hydroxycinnamic acids, phenolic alcohols and other related compounds, stilbenes, flavan-3-ols and flavonols, on different lactic acid bacteria (LAB) strains of the species Oenococcus oeni, Lactobacillus hilgardii and Pediococcus pentosaceus isolated from wine. In general, flavonols and stilbenes showed the greatest inhibitory effects (lowest IC?? values) on the growth of the strains tested (0.160-0.854 for flavonols and 0.307-0.855 g/L for stilbenes). Hydroxycinnamic acids (IC?? > 0.470 g/L) and hydroxybenzoic acids and esters (IC?? >1 g/L) exhibited medium inhibitory effect, and phenolic alcohols (IC?? > 2 g/L) and flavanol-3-ols (negligible effect) showed the lowest effect on the growth of the LAB strains studied. In comparison to the antimicrobial additives used in winemaking, IC?? values of most phenolic compounds were higher than those of potassium metabisulphite for O. oeni strains (e.g., around 4-fold higher for quercetin than for potassium metabisulphite), but lower for L. hilgardii and P. pentosaceus strains (e.g., around 2-fold lower for quercetin). Lysozyme IC?? values were negligible for L. hilgardii and P. pentosaceus, and were higher than those corresponding to most of the phenolic compounds tested for O. oeni strains, indicating that lysozyme was less toxic for LAB than the phenolic compounds in wine. Scanning electron microscopy confirmed damage of the cell membrane integrity as a consequence of the incubation with antimicrobial agents. These results contribute to the understanding of the inhibitory action of wine phenolics on the progress of malolactic fermentation, and also to the development of new alternatives to the use of sulphites in enology.     

己酸菌生长代谢因素与培养应用

论述了己酸菌在生长、繁殖、代谢过程中的主要因素是:营养物质(碳、氮、矿质元素)、水分、温度、酸度、酒精浓度及其他微生物等.又从实践的角度讲述了己酸菌在应用过程中应注意的事项.     

The inhibitory effects of wine phenolics on lysozyme activity against lactic acid bacteria

The lysozyme of hen's egg white is used in winemaking to control spontaneous lactic acid bacteria (LAB). A total of eight LAB strains, isolated from grape must and wine, were used to assess the inhibitory effects of wine phenolics on lysozyme activity. The presence of phenolics, extracted from grape pomace, in growth medium reduced the mortality rate due to the lysozyme activity. This effect was especially clear in the case of strains belonging to Lactobacillus uvarum, Pediococcus parvulus and Oenococccus oeni, which are more sensitive to lysozyme than L. plantarum and L. hilgardii strains. Cell lysis assays carried out on four strains sensitive to lysozyme and Micrococcus lysodeikticus ATCC 4698, used as a reference strain, confirmed the inhibition of grape pomace phenolics on the muramidase. There was no interference from non-flavonoids, flavanols and flavonol compounds, when they were tested individually, on the lysozyme activity against the strains. Anthocyanins extracted from grape skins slightly inhibited the activity only against M. lysodeikticus. However, proanthocyanidins extracted from seed berries, strongly inhibited the lysozyme. In this extract, dimers were the predominant oligomers of flavan-3-ol. The study demonstrated that the effectiveness of lysozyme against LAB in red winemaking is related to the amount of low molecular weight proanthocyanidins that are released when the grapes are macerating.     

复合发酵剂生产风干肠对产品质构及游离氨基酸的影响

采用从传统哈尔滨风干香肠中分离纯化的三种微生物制备成复合发酵剂,进行风干肠的生产,旨在缩短发酵时间,保证生产的稳定性以及提高产品的安全性。复合发酵剂由弯曲乳杆菌、木糖葡萄球菌和近平滑假丝酵母组成,接种量分别为肉重的106、107、107cfu/g。使用发酵剂生产的风干肠,pH在3d内达到理想水平,游离氨基酸含量明显提高,物性学特征也有所改善;水分活度没有显著变化。表明复合发酵剂生产风干肠有利于产品品质。      

Limited stability in cell culture medium and hydrogen peroxide formation affect the growth inhibitory properties of delphinidin and its degradation product gallic acid

In the present study we investigated the stability of anthocyanidins under cell culture conditions and addressed the question whether degradation products might contribute to the cellular effects assigned to the parent compounds. Substantial degradation was found already after 30 min, measured by HPLC/DAD. However, the decrease of detectable anthocyanidins exceeded by far the formation of the respective phenolic acids. From the formed phenolic acids only gallic acid (GA) exhibited growth inhibitory properties. However, also GA was found to be degraded rapidly. Furthermore, the incubation with delphinidin (DEL) or GA resulted in a substantial formation of hydrogen peroxide. The suppression of hydrogen peroxide accumulation by catalase modified significantly the growth inhibitory effects of DEL and GA, indicating that hydrogen peroxide formation might generate experimental artefacts. In summary, the results show that the phenolic acids formed by the degradation of cyanidin (CY), pelargonidin (PG), peonidin (PN) and malvidin (MV) do not contribute to the growth inhibitory effect of the parent compound. The degradation of DEL generates a phenolic acid with substantial growth inhibitory properties (GA). However, taken into account the small proportion of generated GA and its lacking stability, the contribution of GA to the growth inhibitory properties of DEL might be limited.     

Influence of starter culture ratios and warm room treatment on free fatty acid and amino acid in Swiss cheese

Quantification of water-soluble volatile free fatty acids (FFA) and free amino acids (FAA) was performed as a ripening index and an indirect measure of flavor development in Swiss-type cheeses. The objective of this research was to assess the effect of warm room treatment (WRT) and usage ratio of starter cultures, Streptococcus thermophilus and Lactobacillus helveticus vs. propionibacteria, on the concentration of FFA and FAA in pilot plant-scale Swiss cheese. A capillary gas chromatograph equipped with a flame ionization detector was used for the analysis of FFA in Swiss cheese. Free amino acids were analyzed by the Cd-ninhydrin method. Starter culture ratios did not affect development of FAA during the cheese ripening. However, duration of WRT had an effect on the concentration of FAA in the Swiss cheese. Free amino acids increased considerably during WRT. A continuous increase in FAA was shown during 70-d ripening time after WRT. The concentrations of C2:0 and C3:0 fatty acids were affected by starter culture ratios after 2-wk WRT, but these differences had mostly disappeared after 3-wk WRT. Similar concentrations of FFA and FAA reported in previous studies were developed in Swiss cheese with a 3-wk WRT and a 0.33:1 ratio of Streptococcus thermophilus and Lactobacillus helveticus to propionibacteria.     

柑桔培养基中乳酸菌的生长状况研究

采用正交试验对乳酸菌在脱脂乳和桔汁、桔皮汁等培养基及不同发酵温度、时间和菌种条件下，产酸和菌数等进行了测定。结果表明乳酸菌在柑桔培养基中生长良好     

The effects of freeze, dry, and wet grinding processes on rice flour properties and their energy consumption

This study attempted to replace the wet grinding process of rice with a freeze grinding process. The freeze grinding process involved soaking the rice samples in liquid nitrogen before grinding in a dry grinding machine. Three different types of grinders (hammer mill, roller mill, and pin mill) were used in both the freeze and the dry grinding processes. Wet grinding resulted in significantly (P < 0.05) smaller average particle size and a lower percentage of damaged starch than the alternative methods of grinding. Freeze grinding, especially using the hammer mill significantly reduced both the average particle size and the damaged starch content. Moreover, freeze grinding produced a higher yield after sieving in comparison with dry grinding using an identical grinder. In particular, freeze grinding with the hammer mill gave a significantly higher yield after sieving than dry grinding with the hammer mill. The wet grinding process had the significantly highest specific energy consumption (13,868 kJ/kg) due to the large consumption of electrical energy by the many machines in the process. The energy consumption of freeze grinding was similar to dry grinding. Consequently, the freeze grinding process was a viable alternative to the traditional wet grinding process.     

Growth inhibitory effects of anthranilic acid and its derivatives against Legionella pneumophila

Legionella pneumophila is the principal etiologic agent of Legionnaires' disease. We found that the growth of L. pneumophila was markedly inhibited by its own cell lysate and the inhibitory effect was abolished by heat-treatment of the lysate. The genomic library of L. pneumophila was constructed in Escherichia coli and screened to determine the gene involved in the growth inhibition. A clone harboring the gene encoding anthranilate synthase (TrpE), which is involved in tryptophan biosynthesis, exhibited an inhibitory effect on the growth of L. pneumophila. Anthranilic acid exogenously added also exhibited antibacterial activity against L. pneumophila. A series of single-gene-knockout mutants of L. pneumophila lacking tryptophan synthesis genes were constructed and assessed for their susceptibility to anthranilic acid. Although the growth of mutants deficient in anthranilate phosphoribosyltransferase (TrpD) and N-(5'-phosphoribosyl)anthranilate isomerase (TrpF) was not affected by exogenous anthranilic acid, the indole-3-glycerophosphate synthase (TrpC) deficient mutant exhibited an increased susceptibility compared with the parent strain. These observations strongly indicate that 1-(2-carboxyphenylamino)-1'-deoxyribulose-5'-phosphate (CPADR-5'-P), which is an intermediate of tryptophan synthesis from anthranilic acid, is responsible for the growth inhibition of L. pneumophila.     

对香豆酸、阿魏酸和低聚糖阿魏酸酯对酪氨酸酶的抑制效果

通过测定酶的稳态活力、迟滞时间和动力学参数,研究对香豆酸、阿魏酸及低聚糖阿魏酸酯对酪氨酸酶的抑制效果。结果表明,3种物质对酪氨酸酶单酚酶活性均有抑制作用,其中对香豆酸的抑制作用最强,其次为低聚糖阿魏酸酯和阿魏酸。对香豆酸、低聚糖阿魏酸酯和阿魏酸对单酚酶的IC_(50)值分别为0.75,3.20,9.30 mmol/L。对香豆酸和阿魏酸抑制二酚酶活性,IC_(50)值分别为4.3,12.7mmol/L;但低聚糖阿魏酸酯对二酚酶活力没有影响。对香豆酸能明显延长单酚酶反应的迟滞时间,阿魏酸影响很小,而低聚糖阿魏酸酯则缩短迟滞时间。动力学研究结果显示,阿魏酸和低聚糖阿魏酸酯对单酚酶的抑制作用表现为混合性抑制,而对香豆酸为竞争性抑制。     

搅拌器对谷氨酸菌高密度培养的影响

通过改进10m3种子罐的搅拌器,研究不同搅拌器对溶氧系数和谷氨酸高密度培养的影响。结果表明:由六弯叶圆盘涡轮搅拌器改造为六半圆叶圆盘涡轮搅拌器后,种子罐的溶氧系数是改造前的2.36倍,使谷氨酸菌高密度培养时的最终湿菌体量达到25.42%,是改造前的2.88倍。     

Conjugated linoleic acid content in fermented goat milk as affected by the starter culture and the presence of free linoleic acid

The effect of yoghurt starter cultures and probiotic Lactobacillus casei on the formation of conjugated linoleic acid (CLA) and microbial populations of fermented goat milk was investigated during 35 days of cold storage. The addition of hydrolysed sunflower oil as a source of free linoleic acid was investigated. The fermentation process enhanced the content of the cis9, trans11‐CLA isomer in milk, whereas the trans10, cis12‐CLA isomer was not detected in goat milk or control fermented milks. The use of both starters generated trans10, cis12‐CLA only when hydrolysed sunflower oil was supplemented. Populations of streptococci and lactobacilli were affected by the presence of hydrolysed sunflower oil.     

Sex effects on net protein and energy requirements for growth of Saanen goats

Requirements for growth in the different sexes remain poorly quantified in goats. The objective of this study was to develop equations for estimating net protein (NP_G) and net energy (NE_G) for growth in Saanen goats of different sexes from 5 to 45 kg of body weight (BW). A data set from 7 comparative slaughter studies (238 individual records) of Saanen goats was used. Allometric equations were developed to determine body protein and energy contents in the empty BW (EBW) as dependent variables and EBW as the allometric predictor. Parameter estimates were obtained using a linearized (log-transformation) expression of the allometric equations using the MIXED procedure in SAS software (SAS Institute Inc., Cary, NC). The model included the random effect of the study and the fixed effects of sex (intact male, castrated male, and female; n = 94, 73, and 71, respectively), EBW, and their interactions. Net requirements for growth were estimated as the first partial derivative of the allometric equations with respect to EBW. Additionally, net requirements for growth were evaluated based on the degree of maturity. Monte Carlo techniques were used to estimate the uncertainty of the calculated net requirement values. Sex affected allometric relationships for protein and energy in Saanen goats. The allometric equation for protein content in the EBW of intact and castrated males was log₁₀ protein (g) = 2.221 (±0.0224) + 1.015 (±0.0165) × log₁₀ EBW (kg). For females, the relationship was log₁₀ protein (g) = 2.277 (±0.0288) + 0.958 (±0.0218) × log₁₀ EBW (kg). Therefore, NP_G for males was greater than for females. The allometric equation for the energy content in the EBW of intact males was log₁₀ energy (kcal) = 2.988 (±0.0323) + 1.240 (±0.0238) × log₁₀ EBW (kg); of castrated males, log₁₀ energy (kcal) = 2.873 (±0.0377) + 1.359 (±0.0283) × log₁₀ EBW (kg); and of females, log₁₀ energy (kcal) = 2.820 (±0.0377) + 1.442 (±0.0281) × log₁₀ EBW (kg). The NE_G of castrated males was greater than that of intact males and lower than that of females. Using degree of maturity for estimating NP_G and NE_G, we could remove the differences between sexes. These results indicate that NP_G and NE_G differ among sexes in growing Saanen goats, and this difference should be accounted for by feeding systems. Including the degree of maturity as predictor cancels out those differences across sexes in protein and energy requirements.     

对大肠杆菌生物膜具有高抑制能力的乳酸菌的筛选

采用传统抑菌方法和体外生物膜模型,研究并筛选对大肠杆菌生物膜具有较强抑制能力的乳酸菌。结果表明,乳酸菌的抑菌性与抑制大肠杆菌生物膜形成能力之间并没有相关性。筛选得到了5株对保护人体免受大肠杆菌感染具有潜在应用价值的乳酸菌,即7-1、11-3、10-1、13-1、A-1,对生物膜形成量的抑制率分别为84. 59%、85. 19%、70. 09%、64. 59%和65. 20%,通过荧光显微镜观察发现它们均可以完全破坏生物膜的典型结构。通过耐酸耐胆盐实验,进一步筛选出了能很好适应胃肠环境压力的菌株,即菌株A-1(Lactobacillus acidophilus),为今后预防由大肠杆菌引起的感染提供了理论依据。     

Stimulatory and inhibitory effects of protein amino acids on growth rate and efficiency of mixed ruminal bacteria

Mixed ruminal bacteria were incubated in vitro with glucose, xylose, cellobiose, and various protein amino acids replaced isonitrogenously with 25% (i.e., 25 mg of N/L) of ammonia-N, to determine the growth rate and the amount of sugar consumed in the exponential growth phase. The growth rate and efficiency (grams of bacteria per gram of sugars) increased by 46 and 15%, respectively, when a mixture of 20 amino acids was added. On the other hand, neither growth rate nor efficiency increased when any one of these amino acids was added singly, except for Glu and Gln, each of which produced significant but small improvements. The stimulatory effect of the combined amino acids on bacterial growth declined when each of Leu, Trp, Tyr, Glu, Met, Phe, and Val was removed from the original group of 20. When a mixture of only these seven amino acids was used as a supplement, their stimulatory effects on growth rate and efficiency were only 21 and 25%, respectively, of the effects that the mixture of 20 amino acids showed. The effects increased to 76 and 72% on growth rate and efficiency, respectively, when Gly, Cys, and His were supplied in addition to the seven amino acids. The growth rate and efficiency of the ruminal bacteria were inhibited by an addition of each of Ile, Thr, Cys, Phe, Leu, Lys, or Val to ammonia-N, and the effects of the first five of these amino acids were highly significant. Isoleucine, threonine, and phenylalanine were each inhibitory even at a low concentration (1 mg of NL), while cysteine and leucine showed inhibitory effects at higher concentrations (more than 10 mg of N/L). A higher growth rate of the ruminal bacteria when supplemented with amino acid mixtures was accompanied with a higher growth efficiency, which was attributable to a relatively smaller proportion of energy expended on maintenance according to the Pirt derivation.     

Identification of ubiquitin in bovine milk and its growth inhibitory effects on human cancer cell lines

Bovine milk is associated with improved health and reduced risk of several diseases, among them cancer. Milk is a complex mixture of known and unknown components. The components and the mechanisms that contribute to the cancer-preventive effects are largely unknown. We set out to find new peptides in milk and identified ubiquitin (Ub) using matrix-assisted laser desorption ionization-time of flight mass spectrometry and Western blot. Using quantitative Western blot, we estimated the Ub concentration to be about 0.003 μmol/L in milk. We then decided to investigate the effect of treating human colon cancer CaCo-2 cells with Ub, using higher concentrations than in milk. CaCo-2 cells treated with 0.02 to 2.0 μmol/L Ub showed significantly decreased proliferation compared with untreated control cells. A higher growth inhibitory effect than in CaCo-2 cells was found in the neuroblastoma cell line SH-SY5Y treated with 0.02 to 0.2 μmol/L Ub. A bromodeoxyuridine DNA flow cytometric method was used to study cell cycle kinetics in Ub-treated CaCo-2 cells. The data point toward a prolongation of the G₁ phase. The levels of several cell cycle regulatory proteins were affected. Our data point to Ub possibly being one of the components in milk reducing the risk of cancer.     

菊花清除自由基动力学特性及对羟基自由基介导的2-脱氧核糖裂解的抑制作用

目的 研究不同因素对菊花清除自由基能力的影响,鉴定其功能性成分,探索菊花对羟基自由基引导的2-脱氧核糖裂解的抑制作用。方法 测定菊花提取液在不同浓度、温度和反应时间条件下对1,1-二苯基-2-苦基肼自由基(1,1-diphenyl-2-picrylhydrazyl radical,DPPH·)和2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐阳离子自由基[2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)ammonium salt cationic radical,ABTS⁺·]的清除率。采用高效液相色谱法,测定了菊花提取液与DPPH·和ABTS⁺·反应前后供试品溶液中木犀草苷、木犀草素葡萄糖醛酸苷、绿原酸、隐绿原酸、异绿原酸B、异绿原酸A、异绿原酸C的含量。采用体外Fenton反应实验体系,测定菊花提取液对2-脱氧核糖裂解的保护作用。结果 菊花样品浓度、温度和反应时间对DPPH·和ABTS⁺·的清除率均有影响。与DPPH·和ABTS⁺...     

Free Zn(2+) enhances inhibitory effects of EGCG on the growth of PC-3 cells

Epigallocatechin-3-gallate (EGCG), a major component of green tea, has both preventive and therapeutic beneficial actions in prostate cancer. In the present study, we compared the growth inhibitory effects and the antioxidant and ability to modify cell membrane permeation of zinc-EGCG complex and Zn2+/EGCG mixture on androgen-insensitive prostate cancer (PC-3) cells. It was noted that free Zn2+ enhanced the growth inhibitory effects of EGCG on PC-3 cells at 160 micromol/L concentration,whereas zinc-EGCG complex was ineffective. EGCG showed potent free radical scavenging ability in the presence of Zn2+. EGCG in the presence of Zn2+ was more effective than EGCG alone in enhancing the permeability of the cell membrane, whereas zinc-EGCG complex had no effect on PC-3 cell membrane permeability. These results indicate that though Zn2+ enhanced the action of EGCG on PC-3 cells, zinc-EGCG complex is highly unlikely to be formed in the presence of Zn2+ and EGCG to explain the potentiating action of Zn2+ on the growth inhibitory property of EGCG on PC-3 cells.