Amounts Of Organic Acids Research Articles

Barley malt wort fermentation by exopolysaccharide-forming Weissella cibaria MG1 for the production of a novel beverage

The growing interest of governments and industry in developing healthy and natural alternative foods and beverages that will fulfil the consumer drive towards a healthy lifestyle and clean-label, natural diet has led to an increase in traditional lactic acid bacteria fermentation research. In particular, this research aims to address the organoleptic modulation of beverages using in situ-produced bacterial polysaccharides. Weissella cibaria MG1 is capable of producing exopolysaccharides (dextran) and oligosaccharides (glucooligosaccharides) during sucrose-supplemented barley-malt-derived wort fermentation. Up to 36·4g l(-1) of dextran was produced in an optimized system, which improved the rheological profile of the resulting fermentate. Additionally, small amounts of organic acids were formed, and ethanol remained below 0·5%(v/v), the threshold volume for a potential health claim designation. The results suggest that the cereal fermentate produced by W.cibaria MG1 could be potentially used for the production of a range of novel, nutritious and functional beverages. Using conventional raw materials and traditional processes, novel LAB-fermented beverages can be produced representing an innovative mechanism towards fulfilling the aim to decrease government and personal costs as well as potentially ameliorating consumer lifestyle regarding dietary-related disease.

Fermentation characteristics of yeasts isolated from traditionally fermented masau (Ziziphus mauritiana) fruits

Yeast strains were characterized to select potential starter cultures for the production of masau fermented beverages. The yeast species originally isolated from Ziziphus mauritiana (masau) fruits and their traditionally fermented fruit pulp in Zimbabwe were examined for their ability to ferment glucose and fructose using standard broth under aerated and non-aerated conditions. Most Saccharomyces cerevisiae strains were superior to other species in ethanol production. The best ethanol producing S. cerevisiae strains, and strains of the species Pichia kudriavzevii, Pichia fabianii and Saccharomycopsis fibuligera were tested for production of flavor compounds during fermentation of masau fruit juice. Significant differences in the production of ethanol and other volatile compounds during fermentation of masau juice were observed among and within the four tested species. Alcohols and esters were the major volatiles detected in the fermented juice. Trace amounts of organic acids and carbonyl compounds were detected. Ethyl hexanoate and ethyl octanoate were produced in highest amounts as compared to the other volatile compounds. S. cerevisiae strains produced higher amounts of ethanol and flavor compounds as compared to the other species, especially fatty acid ethyl esters that provide the major aroma impact of freshly fermented wines. The developed library of characteristics can help in the design of mixtures of strains to obtain a specific melange of product functionalities.

Influence of oxidation on fulvic acids composition and biodegradability

Oxidation is well-known process of transforming natural organic matter during the treatment of drinking water. Chlorine, ozone, and chlorine dioxide are common oxidants used in water treatment technologies for this purpose. We studied the influence of different doses of these oxidants on by-products formation and changes in biodegradable dissolved organic carbon (BDOC) and molecular weight distribution (MWD) of fulvic acids (FA) with different BDOC content.Chlorination did not significantly change the MWD of FA and disinfection by-products formation. However, higher molecular weight compounds, than those in the initial FA, were formed. It could be a result of chlorine substitution into the FA structure. Chlorine dioxide oxidized FA stronger than chlorine. During ozonation of FA, we found the highest increase of BDOD due to the formation of a high amount of organic acids and aldehydes. FA molecules were transformed into a more biodegradable form. Ozonation is the most preferable process among those observed for pre-treatment of FA before biofiltration.

효모의 종류를 달리하여 제조한 Black Raspberry 발효주의 품질 특성

시판 효모 4가지(Fermivin, FM; Saf-instant yeast red, SI; Angest wine active dry yeast, AW; Angest instant yeast high sugar, AI)를 이용하여 복분자 발효주를 제조하고, 품질 특성을 비교하였다. 환원당 함량은 FM(2.7%)과 AI(2.8%)가 SI(2.4%)와 AW(2.5%)보다 높았으며, 검출된 주요 유리당인 glucose의 함량은 AW와 AI에서 유의적으로 높았다. 알코올 함량은 AW(11.95%)에서 가장 높고, SI(11.75%)에서 가장 낮았다. pH는 FM(pH 3.73)에서 가장 낮았으며, 총 산도는 효모별로 차이가 없었다. 모든 시료에서 검출된 주요 유기산은 citric acid였으며, 효모별로 검출된 유기산 함량은 달랐다. Malic acid의 경우 SI(2.92 mg/mL)에서 가장 많았고 AI(1.83 mg/mL)에서 가장 적었다. L, a, b 값은 SI에서 높고 AI에서 낮았으며, 탁도는 효모에 따라 차이가 없었다. 복분자 발효주의 total phenolics와 total anthocyanin 함량은 효모 별로 차이가 없었으나, 국내에서 판매되는 수입산 레드 와인보다 높았다. 항산화능 역시 효모별로 차이가 없었으나 FM, AI, AW, SI 순으로 높았으며, 항산화능 지표에는 total phenolics와 anthocyanin의 함량뿐만 아니라 anthocyanin 조성도 영향을 미쳤다.

Interaction of acid exudates in chickpea with biological activity of Bacillus thuringiensis towards Helicoverpa armigera

The gram pod borer, Helicoverpa armigera, is one of the most important constraints to chickpea production. High acidity of chickpea exudates is associated with resistance to pod borer, H. armigera; however, acidic exudates in chickpea might influence the biological activity of the bacterium, Bacillus thuringiensis (Bt), applied as a foliar spray or deployed in transgenic plants for controlling H. armigera. Therefore, studies were undertaken to evaluate the biological activity of Bt towards H. armigera on chickpea genotypes with different amounts of organic acids. Significantly lower leaf feeding, larval survival and larval weights were observed on ICC 506EB, followed by C 235, and ICCV 10 across Bt concentrations. Leaf feeding by the larvae and larval survival and weights decreased with an increase in Bt concentration. However, rate of decrease in leaf feeding and larval survival and weights with an increase in Bt concentration was greater on L 550 and ICCV 10 than on the resistant check, ICC 506EB, suggesting that factors in the resistant genotypes, particularly the acid exudates, resulted in lower levels of biological activity of Bt possibly because of antifeedant effects of the acid exudates. Antifeedant effects of acid exudates reduced food consumption and hence might reduce the efficacy of Bt sprays on insect-resistant chickpea genotypes or Bt-transgenic chickpeas, although the combined effect of plant resistance based on organic acids, and Bt had a greater effect on survival and development of H. armigera than Bt alone.

Catalytic hydroprocessing of fast pyrolysis bio-oil from Chlorella

Catalytic hydroprocessing of the bio-oil obtained through fast pyrolysis of Chlorella was carried out in a bench-scale continuous-flow fixed-bed reactor equipped with a Ni-Co-Pd/γ-Al2O3 catalyst. The effects of the hydrogenation temperature and the H/oil molar ratio on the moisture content, calorific value, viscosity and cetane number of the refined bio-oils were investigated at the pressure of 2×106 Pa, It was shown that the yield of the refined oil reached 89.6%, and the calorific value and cetane number were increased by 17.94% and 71.2% respectively, while the viscosity was decreased by 66.32% at the temperature of 300°C, the pressure of 2×106 Pa and the H/oil molar ratio of 120. The elemental analysis and GC-MS analysis results of the bio-oil before and after hydrogenation show that the H/C atomic ratio was increased from 1.55 to 1.97, while the oxygen, nitrogen and sulfur contents were significantly decreased. The deoxidation degree reached 80.46%. The amounts of organic acids, esters, ketones and aldehyde in the refined oils were obviously decreased, while those of alcohols and alkanes were markedly increased.

복분자의 효소 추출 공정의 최적화 및 성분 변화

The objective of this study is to investigate the optimal condition for macerating enzymatic extraction process that leads to the highest yield and the largest extracted amount of bio-active contents from Rubus coreanus Miq.fruit. The optimal extraction conditions were found as the following: The initial amount of the water added to the fruit was 20~30% by weight. The mixing ratio used for the macerating enzyme was 4: 1: 2 (w: w: w) for cellulase:pectinase:amylogucosidase, and the amount of the macerating enzyme added was 2%by weight. The extraction process was done at a temperature of 45~50℃ for 10 hours. The extraction yields on Rubus coream Miq. fruit by macerating enzymatic extraction process was increased by 84.3% compared to that of hot-water extraction process. The amounts of organic acids and vitamin found in the extract were also higher. The amount of polyphenol and anthocyanim contents in extract were 185% and 257% of those from hot-water extraction, respectively. These results suggest that macerating enzymatic extraction is an effective method to boost extraction yield and to increase the amount of extraction of bio-active contents from Rubus coreanus Miq. fruit.

Online atmospheric pressure chemical ionization ion trap mass spectrometry (APCI-IT-MS<sup>n</sup>) for measuring organic acids in concentrated bulk aerosol – a laboratory and field study

Abstract. The field application of an aerosol concentrator in conjunction with an atmospheric pressure chemical ionization ion trap mass spectrometer (APCI-IT-MS) at the boreal forest station SMEAR II at Hyytiälä, Finland, is demonstrated in this study. APCI is a soft-ionization technique allowing online measurements of organic acids in the gas and particle phase. The detection limit for the acid species in the particle phase was improved by a factor of 7.5 to 11 (e.g. ∼40 ng m3 for pinonic acid) by using the miniature versatile aerosol concentration enrichment system (mVACES) upstream of the mass spectrometer. The APCI-IT-MS was calibrated in the negative ion mode with two biogenic organic acid standards – pinic acid and pinonic acid. Pinic acid was used as a surrogate for the quantification of the total amount of organic acids in the ambient aerosol based on the total signal intensities in the negative ion mode. The results were compared with the total organic signal of a C-ToF-AMS during the HUMPPA-COPEC 2010 field campaign. The campaign average contribution of organic acids measured by APCI-IT-MS to the total submicron organic aerosol mass was estimated to be about 60%, based on the response of pinic acid. Very good correlation between APCI-IT-MS and C-ToF-AMS (Pearson's R = 0.94) demonstrates soft-ionization mass spectrometry as a complimentary technique to AMS with electron impact ionization. MS2 studies of specific m/z ratios recorded during the HUMPPA-COPEC 2010 field campaign were compared to MS2 studies of selected monoterpene oxidation products formed in simulation chamber experiments. The comparison of the resulting fragments shows that oxidation products of the main VOCs emitted at Hyytiälä (α-pinene and Δ3-carene) cannot account for all of the measured fragments. Possible explanations for those unaccounted fragments are the presence of unidentified or underestimated biogenic SOA precursors, or that different products are formed by a different oxidant mixture of the ambient air compared to the chamber ozonolysis.

Root exudation pattern of Typha latifolia L. plants after copper exposure

Typha latifolia L. is an aquatic plant that has been widely exploited for the aims of phytoremediation. The main reason why we have chosen this plant species for the current study is its capacity to accumulate and detoxify heavy metals. The main topic of the investigation focused on the root uptake of copper (II) nitrate and copper (II) sulfate and the impact of different chemical copper species on the excreted organic acids. Oxalic, malic, acetic and lactic acids were determined using capillary electrophoresis; a comparison between the concentration and the time course during 7 days of treatment was performed. There is a correlation between the total copper (II) sulfate concentration in the roots and the total amount of the excreted organic acids. In addition to that organic acids are involved in the detoxification mechanisms of Typha latifolia for copper (II) nitrate and copper (II) sulfate. Different from so far investigated plant species the highest amounts of organic acids are excreted from T. latifolia roots not in the first hours after treatment, but up to 7 days later.

Adsorption of organic acids on magnetite nanoparticles, pH-dependent colloidal stability and salt tolerance

The adsorption of different organic acids and their influence on the pH-dependent charging, salt tolerance and so the colloidal stability of magnetite nanoparticles are compared. Adsorption isotherms of citric acid – CA, gallic acid – GA, poly(acrylic acid) – PAA, poly(acrylic-co-maleic acid) – PAM and humic acid – HA were measured. The pH-dependent charge state of MNPs was characterized by electrophoretic mobility and their aggregation by dynamic light scattering. The salt tolerance was tested in coagulation kinetic experiments. Although the adsorption capacities, the type of bonding (either H-bonds or metal ion-carboxylate complexes) and so the bond strengths are significantly different, the following general trends have been found. Small amount of organic acids at pH<∼8 (the pH of PZC of magnetite) – relevant condition in natural waters – only neutralizes the positive charges, and so promotes the aggregation and sedimentation of nanoparticles. Greater amounts of organic acid, above the charge neutralization, cause the sign reversal of particle charge, and at high overcharging promote stabilization and dispersing. The thicker layer of PAA, PAM and HA provides better electrosteric stability than CA and GA. GA undergoes surface polymerization, thereby improving stabilization. The organic acids studied here eliminate completely the pH sensitivity of amphoteric magnetite, but only the polyanionic coverage provides significant increase in resistance against coagulating effects of salts at neutral pH commonly prevailing in natural waters.

흑미 첨가 막걸리의 항산화 및 발효 특성

본 연구는 흑미를 첨가하여 막걸리를 제조하여 항산화 및 발효특성을 살펴보았다. 항산화 활성은 대조구에 비해 흑미 첨가구가 높았으며 특히 DPPH 라디칼 소거능은 안토시아닌 함량과 비례하였다. 발효 3일째, pH는 급격히 감소하였으며 대조구에 비해 흑미 첨가구가 낮았다. 환원당과 유리당은 1일째 급격히 증가하였다가 그 이후 감소하는 경향을 나타내었는데 이는 발효 초기에 당화 효소 활성으로 쌀의 전분이 glucose와 maltose 등으로 분해되기 때문이다. 모든 유기산은 발효 동안 증가하였으며 lactic acid가 가장 높은 증가율을 나타내었다. 발효 동안 흑미 첨가 막걸리의 lactic acid와 succinic acid는 대조구와 큰 차이를 보이지 않았다. 발효 초기 젖산균수가 증가하여 3일째 최대에 달하였으며 이는 lactic acid가 급증한 시기와 일치하였다. 또한 흑미 첨가량이 많을수록 젖산균수가 높았다. 색도는 흑미의 붉은색의 영향으로 대조구에 비해 흑미 첨가구의 a값이 높았다. 관능검사 결과 외관은 흑미 첨가구가 높은 점수를 받았으나 전체적으로 단맛과 신맛의 영향을 받아 대조구와 20% 첨가구를 선호하는 것으로 나타났다. 흑미를 첨가할수록 항산화 성분은 증가하나 관능평가 결과로 보았을 때 흑미는 20% 수준 첨가하는 것이 바람직한 것으로 나타났다.

Influence of Different pH Conditions and Phosphate Sources on Phosphate Solubilization by Pantoea agglomerans DSM3493

Pantoea agglomerans DSM3493 was isolated from green house soils collected from Chungchugnam-do province, Gongju-Gun area in South Korea and phosphate solubilization and organic acid production of the strain were assessed using three types of insoluble phosphate sources (Ca phosphate, Fe phosphate and Al phosphate) under three different pH conditions (7, 8 and 9). The highest Ca phosphate solubilization (651 μg mL -1 ) was recorded at pH 7 followed by pH 8 and 9 (428 and 424 μg mL -1 respectively). The solubilization rate was found to be 80.4, 98.1 and 88.7 μg mL -1 (for Fe phosphate containing medium) and 9.3, 12.1 and 29.8 μg mL -1 (for the Al phosphate containing medium) respectively at pH 7, 8 and 9. Though increasing pH of the medium caused reduction in the rate of solubilization of Ca phosphate, solubilization of Fe and Al phosphates enhanced with increasing pH. By contrast, the highest amount of organic acid was produced with Ca phosphate while the lowest was recorded with the presence of Al phosphate. Among the organic acids, gluconic acid production was found to be the highest, followed by oxalic acid and citric acid regardless the source of phosphate. Results can thus be concluded that the production of organic acids appears to play a significant role in the inorganic phosphate solubilization.

Acid-Mediated Prevention of Aspartimide Formation in Solid Phase Peptide Synthesis

Aspartimide formation is one of the major obstacles that impedes the solid phase synthesis of large peptides and proteins. Until now, no cost-effective strategy to suppress this side reaction has been developed. Here it is demonstrated that addition of small amounts of organic acids to the standard Fmoc cleavage agent piperidine efficiently prevents formation of aspartimide side products. This effect is shown to be virtually independent of the acid strength.

Experimental and modeling investigation of the low-temperature oxidation of n-heptane

The low-temperature oxidation of n-heptane, one of the reference species for the octane rating of gasoline, was investigated using a jet-stirred reactor and two methods of analysis: gas chromatography and synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) with direct sampling through a molecular jet. The second method allowed the identification of products, such as molecules with hydroperoxy functions, that are not stable enough to be detected using gas chromatography. Mole fractions of the reactants and reaction products were measured as a function of temperature (500–1100K), at a residence time of 2s, at a pressure of 800Torr (1.06bar) and under stoichiometric conditions. The fuel was diluted in an inert gas (fuel inlet mole fraction of 0.005). Attention was paid to the formation of reaction products involved in the low-temperature oxidation of n-heptane, such as olefins, cyclic ethers, aldehydes, ketones, species with two carbonyl groups (diones), and ketohydroperoxides. Diones and ketohydroperoxides are important intermediates in the low-temperature oxidation of n-alkanes, but their formation have rarely been reported. Significant amounts of organic acids (acetic and propanoic acids) were also observed at low temperatures. The comparison of experimental data and profiles computed using an automatically generated detailed kinetic model is satisfactory overall. A route for the formation of acetic and propanoic acids was proposed. Quantum calculations were performed to refine the consumption routes of ketohydroperoxides toward diones.

The effect of clear cutting on podzolisation and soil carbon dynamics in boreal forests (Middle Taiga zone, Russia)

Boreal forests are one of the most important terrestrial carbon sink, and a large portion of C is allocated in soil for long-term storage. However forest harvesting may quickly affect soil carbon stocks and dynamics, especially where organic substances drive the soil-forming processes, such as in Podzols. To evaluate the effects of clear cutting on carbon dynamics and podzolisation process over a short time period, a pristine boreal forest (Komi Republic, Russian Federation) and a recently clear cut site (5year-old) were selected. Soils are polygenic: podzolisation occurs within the clay-depleted eluvial horizon, formed by a previous lessivage process. Because podzolisation can start only after the eluvial horizon has reached a sort of threshold, bisequal soils allow to individuate comparable pedogenic conditions prior to anthropogenic disturbances.After harvesting, C storage tended to increase in the upper part of the soil profile (organic layer and podzolic sequum) from 2.2 to 5.0kgm−2. The abundance of woody materials on the forest floor together with an increase in soil water saturation, discernible by the vegetation survey and iron fractionation, prevented litter degradation and allowed organic matter accumulation at the soil surface. Fulvic acids (FA) in the organic layer of the pristine site showed a low incorporation of polysaccharide and proteinaceous moieties, confirming a higher degradation of the humified fraction than at the clear cut site. The lack of disturbances allowed a selection of FA with the more oxidised and mobile fractions accumulating in the deeper horizons, as currently observed in Podzols. Almost no differences were instead found in the chemical composition of FA along the profile from the clear cut site. A larger portion of FA showed the tendency to migrate through the profile after clear cutting even below the Bhs horizon (C-fulvic acid/C-humic acid >1) with a marked increase in the FA-carbon stocks with respect to the pristine forest soil (0.66 and 0.30kgm−2 down to 30cm, respectively).Clear cutting also affected Al and Fe dynamics. The reducing conditions acted upon soil mineral surfaces and enhanced Fe mobilisation probably both in the ionic form and complexed with organic matter. The Al dynamics was instead more related to short term transformations of the layer silicate phases. Traces of a poorly crystalline chlorite were detectable in the Bhs in the pristine forest, but at the clear site only hydroxy-interlayered vermiculite was present. The high amounts of organic acids that migrated through the Bhs after clear cutting may have partially complexed the Al from pedogenic chlorite, giving rise to hydroxy-interlayered behaviour, as normally occurs in Podzol eluvial horizons from where the organic Al-complexes migrate.Our findings suggested that if this trend proceeds further the whole podzolic sequum may migrate downwards. This may have important implication on C budget, as organic carbon will be transferred deeper in the soil profile limiting its losses at least over a short time period.

Effect of organic acids on the growth and lipid accumulation of oleaginous yeast Trichosporon fermentans.

BackgroundMicrobial lipids have drawn increasing attention in recent years as promising raw materials for biodiesel production, and the use of lignocellulosic hydrolysates as carbon sources seems to be a feasible strategy for cost-effective lipid fermentation with oleaginous microorganisms on a large scale. During the hydrolysis of lignocellulosic materials with dilute acid, however, various kinds of inhibitors, especially large amounts of organic acids, will be produced, which substantially decrease the fermentability of lignocellulosic hydrolysates. To overcome the inhibitory effects of organic acids, it is critical to understand their impact on the growth and lipid accumulation of oleaginous microorganisms.ResultsIn our present work, we investigated for the first time the effect of ten representative organic acids in lignocellulosic hydrolysates on the growth and lipid accumulation of oleaginous yeast Trichosporon fermentans cells. In contrast to previous reports, we found that the toxicity of the organic acids to the cells was not directly related to their hydrophobicity. It is worth noting that most organic acids tested were less toxic than aldehydes to the cells, and some could even stimulate the growth and lipid accumulation at a low concentration. Unlike aldehydes, most binary combinations of organic acids exerted no synergistic inhibitory effects on lipid production. The presence of organic acids decelerated the consumption of glucose, whereas it influenced the utilization of xylose in a different and complicated way. In addition, all the organic acids tested, except furoic acid, inhibited the malic activity of T. fermentans. Furthermore, the inhibition of organic acids on cell growth was dependent more on inoculum size, temperature and initial pH than on lipid content.ConclusionsThis work provides some meaningful information about the effect of organic acid in lignocellulosic hydrolysates on the lipid production of oleaginous yeast, which is helpful for optimization of biomass hydrolysis processes, detoxified pretreatment of hydrolysates and lipid production using lignocellulosic materials.

Analysis of Nutritional Constituents in Twenty Citrus Cultivars from the Mediterranean Area at Different Stages of Ripening

Twenty Citrus cultivars grown in the Mediterranean climate were analysed at different stages of fruit maturity to determinate changes in organic acids, vitamin C and sugars. High-performance liquid chromatographic methods were used to identify and quantify of these compounds. The influences of variety, rootstocks and different stages of fruit maturity were observed. Generally, the vitamin C content was higher in varieties grafted on Troyer citrange that the corresponding cultivars grafted on Cleopatra mandarin. At commercial harvest stage, lemons, clementine mandarins and sweet oranges, showed the highest concentrations of vitamin C; citrons, limes and lemons, the higher amounts of organic acids; and mandarins and hybrids the highest amounts of sugars. Since sugars and acids played an important role in fruit flavor and their nature and concentration largely affect taste characteristic and organoleptic quality, we hope to relate genotypes and differences in final fruit quality. We have found clear differences in the content of sugars, ascorbic and organic acids for the different groups in agreement with the Citrus classification. Also climatic and cultural factors have affected to fruit quality, and anticipate or delay the collection generally results in a loss of bioactive compounds. The fruit quality was affected differently and we have observed differences in accordance with the rootstocks used but, the major differences in nutritional composition must be attributed mainly to genetic factors. The data presented are an important factor to chose varieties with a high potential as nutraceutical source.

Ruminal acidosis in feedlot cattle: Interplay between feed ingredients, rumen function and feeding behavior (a review)

Ruminal acidosis in feedlot cattle is a common metabolic disorder of digestive origin with significant economic and welfare implications. The main risk factors are high grain, low roughage diets because of their high rate and extent of degradation by rumen microbes. Diet formulation should therefore consider the proportion, method of processing and type of grain; the proportion, fiber concentration and particle size of forages; and the use of feed additives. Grain and forage characteristics, and feed additives, may determine the rate and amount of organic acids produced in the rumen. In addition, diet formulation may also affect feeding behavior, i.e. feed intake and chewing behaviors, which has a great influence on ruminal fluid acid–base balance. Feeding characteristics associated with low ruminal fluid pH are: high dry matter intake and ingestion of large meals because of the greater amount of acid production per period of time, high eating rate because of lower feed ensalivation, short time spent chewing while eating and ruminating because of lower daily saliva production, and large variations in feeding behavior patterns throughout the day such as less frequent meals and rumination. The ruminal acid–base balance requires synchronization in time between acid production and neutralization through saliva, as well as elimination through absorption, wash-out from the rumen, and metabolization. Greater proportions of roughage in the diet and greater particle size leads to slower eating rate and longer chewing time which favors saliva production, and smaller meals which reduce the amount of acid production. Adaptation of feeding behavior to diets with greater proportion of concentrates also plays an important role, as smaller meals and more even distribution of intake throughout the day lead to a better synchronization in time between acid production and elimination or neutralization. Monensin increases the frequency of meals and reduces meal size which is beneficial for ruminal fluid pH, whereas sodium bicarbonate at high concentrations produces the opposite effects and reduces rumination. In addition to diet formulation, feeding management and the social environment may also affect feeding behavior and consequently, ruminal fluid pH. Delivering the feed twice daily results in better synchronization in time between feed intake (acid production), rumination (saliva production), and elimination of fermentation products from the rumen. In contrast, feeding programs that restrict feed amount and time available allow animals to become hungry, whereas restricted feeding space increases competition among group mates. Both situations lead to fewer and larger meals eaten at a faster rate, and consequently, greater risk of ruminal acidosis.

Germination, growth, photosynthesis and ionic balance inSetaria viridisseedlings subjected to saline and alkaline stress

Guo, R., Zhou, J., Hao, W., Gong, D., Zhong, X., Gu, F., Liu, Q., Xia, X., Tian, J. and Li, H. 2011. Germination, growth, photosynthesis and ionic balance in Setaria viridis seedlings subjected to saline and alkaline stress. Can. J. Plant Sci. 91: 1077–1088. Setaria viridis seeds and seedlings were subjected to saline and alkaline stress to determine their effects on germination and growth indices, and physiological parameters. The treatments consisted of solutions of NaCl:Na2SO4for saline stress and NaHCO3:Na2CO3for alkaline stress, at different concentrations. Germination, growth, photosynthesis, chlorophyll fluorescence and ionic balance were determined to elucidate the difference in the mechanism of saline and alkaline stress damage to S. viridis seedlings, and their physiological adaptive mechanism to stress. Germination indices decreased and, germ and root growth were severely inhibited with increased concentrations, especially under alkaline stress. We also found that alkaline stress had a more severe effect on S. viridis seedlings than saline stress, which was demonstrated by greater reduction in relative growth rate, water content and root system activity. Similarly, the reduction in photosynthesis and chlorophyll fluorescence was greater under alkaline than saline stress. Alkaline stress also appeared to exacerbate the ionic imbalance generated by saline stress; alkaline stress caused a heavy precipitate of phosphate and metal ions, excluding Na+and K+, and the loss of NO3−and H2PO4−, which caused a sharp decrease in ionic activity and free concentrations of various ions. Our results suggest that damage caused by alkaline stress might come from greater influx of Na+than caused by saline stress. Setaria viridis responds by synthesizing greater amounts of organic acids than are required to counter salinity to address the intracellular ion imbalance; this process is at the cost of the plant's already diminished energy resource.

Part I. The Use of Lactobacillus Plantarum Starter Cultures to Inhibit Rootlet Growth during Germination of Barley, Reducing Malting Loss, and its Influence on Malt Quality

The reduction of malting loss has been an ambition for many decades, with the aim to achieve higher yields in the malting process. Organic acids have been shown to possess restricting effects on rootlet growth if exceeding critical concentrations. Lactic acid bacteria are able to produce high amounts of organic acids. In the present study, the potential of a broad selection of Lactobacillus plantarum strains as starter cultures to reduce malting loss and their subsequent impact on malt quality were examined. Starter cultures were prepared in a modified de Man, Rogosa, and Sharp medium and added to the grain immediately after steeping. A chemically acidified solution was added to mimic the impact of acids produced by the L. plantarum strains on rootlet growth suppression. The bacterial fermentation broths of all L. plantarum strains tested reduced malting loss to a similar extent accompanied by lower friability values and increased β-glucan contents. Malting loss could be reduced from approx. 7.3 to 2.3%. Resteeping in the chemically acidified solution reduced malting loss to approx. 3.5%. In both cases, the reduction in malting loss was accompanied with lower enzyme activities, in particular α-amylase, limit dextrinase, and β-glucanase. Although the quality of malt produced with reduced malting loss was diminished compared with control malt, parameters such as soluble nitrogen, free amino nitrogen, β-glucan, and friability were still in a range that can be seen as sufficient for brewing purposes.