Decrease In Citric Acid Concentration Research Articles

Deciphering the effect of citric acid on arsenic adsorption with phosphorene in aqueous solution

This paper presents the first attempt to explore the potential of phosphorene as an adsorbent for arsenic [AS(III) and As(V)] removal under competition adsorption with citric acid (CA). In this study, the phosphorene was prepared by the exfoliation method. Results showed that CA reduced As(III) adsorption due to the lower stability constant of organic-As(III) complexes. The adsorption capacity with phosphorene was enhanced with a decrease in the initial concentration of CA. The adsorption rates for As(III) and As(V) were 0.033 and 0.069 min− 1, respectively, according to kinetics analysis. The maximum adsorption capacity obtained using the Langmuir model was 8.9 mg g− 1 for As(III) at pH 7 with 0.1 mM CA addition, and the As(V) adsorption capacity of phosphorene was 20 mg g− 1.

Effect of pH on malolactic fermentation in southern Italian wines

This study investigated the influence of pH on malolactic fermentation (MLF) in white wines (adjusted to pH 3.2, 3.4 and 3.8, respectively) from Falanghina grapes and red wines (adjusted to pH 3.4 and 3.8, respectively) from Tintilia grapes. The wines were inoculated with Oenococcus oeni and Lactobacillus plantarum strains, and a mix of them (50:50), in red Tintilia only. The time required to complete MLF in wines from white Falanghina grapes at pH 3.4 and 3.8 was lower with O. oeni, while MLF did not occur at pH 3.2. In red Tintilia, MLF was always completed within 35 days; at high pH (3.8) a significant increase in histamine was detected, while the decrease in citric acid concentration caused an increase in volatile acidity. Sensorial analysis showed an enhancement of red berry and spicy notes in red Tintilia at pH 3.8. PCA on white Falanghina showed that wines at pH 3.2 were located on the negative side of PC1 with higher scores for dry vegetable, sulphide, violet and toasted attributes. Wines at pH 3.4 and 3.8 were located on the positive side of the PC1 with butter and apple attributes. L. plantarum enhanced floral notes in white Falanghina wines and showed a good organoleptic impact on red Tintilia wines, which sensorial intensity was improved by a commercial mix (50:50) of O. oeni and L. plantarum.

Lactic acid bacteria involved in cocoa beans fermentation from Ivory Coast: Species diversity and citrate lyase production

Microbial fermentation is an indispensable process for high quality chocolate from cocoa bean raw material. lactic acid bacteria (LAB) are among the major microorganisms responsible for cocoa fermentation but their exact role remains to be elucidated. In this study, we analyzed the diversity of LAB in six cocoa producing regions of Ivory Coast. Ribosomal 16S gene sequence analysis showed that Lactobacillus plantarum and Leuconostoc mesenteroides are the dominant LAB species in these six regions. In addition, other species were identified as the minor microbial population, namely Lactobacillus curieae, Enterococcus faecium, Fructobacillus pseudoficulneus, Lactobacillus casei, Weissella paramesenteroides and Weissella cibaria. However, in each region, the LAB microbial population was composed of a restricted number of species (maximum 5 species), which varied between the different regions. LAB implication in the breakdown of citric acid was investigated as a fundamental property for a successful cocoa fermentation process. High citrate lyase producer strains were characterized by rapid citric acid consumption, as revealed by a 4-fold decrease in citric acid concentration in the growth medium within 12h, concomitant with an increase in acetic acid and lactic acid concentration. The production of citrate lyase was strongly dependent on environmental conditions, with optimum production at acidic pH (pH<5), and moderate temperature (30–40°C), which corresponds to conditions prevailing in the early stage of natural cocoa fermentation. This study reveals that one of the major roles of LAB in the cocoa fermentation process involves the breakdown of citric acid during the early stage of cocoa fermentation through the activity of citrate lyase.

Chemostat study of citric acid production from glycerol by Yarrowia lipolytica

The aim of the study was to examine how the dilution rate and the chemical composition of the production medium impacts on the synthesis of citric acid by the Yarrowia lipolytica strain Wratislavia AWG7 from glycerol in a chemostat culture. The yeast Y. lipolytica Wratislavia AWG7, an acetate (acet −) and morphological (fil −) mutant, was cultured in a nitrogen- and phosphorus-limited medium at the dilution rate of 0.009–0.031 h −1 in the chemostat. Under steady-state conditions, the increase in the dilution rate was paralleled by the decrease in citric acid concentration (from 86.5 to 51.2 g L −1), as well as by the increase in the volumetric rate (from 0.78 to 1.59 g L −1 h −1) and specific rate (from 0.05 to 0.18 g g −1 h −1) of citric acid production. The yield of the production process varied from 0.59 to 0.67 g g −1. In a 550-h continuous culture of the yeast test, at a dilution rate of 0.01 h −1, in a medium with enhanced concentrations of carbon, nitrogen and phosphorus sources, the concentration of citric acid, the concentration of biomass and the volumetric rate of citric acid production were 97.8 g L −1, 22.2 g L −1 and 0.98 g L −1 h −1, respectively. The yield of the process decreased to 0.49 g g −1. The number of dead cells did not exceed 1% while that of the budding cells accounted for about 20%. Owing to the low content of isocitric acid and polyols, the fermentation process was characterized by a high purity. This study has produced the following finding: the double mutant Y. lipolytica AWG7 is an effective citric acid producer, with the ability to preserve its properties unchanged during the long run of the continuous chemostat process. This is a valued technological feature of such mutants.

The evaluation of markers of prostatic inflammation and function of the prostate gland in patients with chronic prostatitis

Introduction:The aim of the study was to determine the numbers of polymorphonuclear (PMN) leukocytes and PMN elastase and citric acid concentrations in chronic prostatitis patients regardless of etiology and in those with Chlamydia trachomatis infection of the prostate gland.Materials and Methods:The study involved 46 patients with chronic prostatitis. Expressed prostatitc secretions (EPS) were obtained to determine the leukocyte count, PMN elastase (ELISA) and citric acid concentrations (UV method), and the occurrence of C. trachomatis infection (ligase chain reaction).Results:Increased PMN cell counts (≥10 per high-power field) were found in 73.9% of patients and increased PMN elastase concentration (<250 ng/ml) in 78.3%. In 44.4% of the patients the elastase concentration indicated moderate (250–1000 ng/ml) and in 55.6% acute infection (≥1000 ng/ml). Decreased citric acid concentration (<18.12 mg/ml) in the EPS was found in 65.2% of the men. C. trachomatis prostate infection was detected in 17.4% of the patients and all of these men had higher inflammation parameters and lower citric acid concentrations.Conclusions:C. trachomatis prostate inflammation was accompanied by an increase in inflammation markers and a decrease in citric acid concentration.

EFFECT OF SOLUBLE SOLIDS AND TEMPERATURE ON ASCORBIC ACID DEGRADATION IN LEMON JUICE STORED IN GLASS BOTTLES

ABSTRACTLemon juice at concentrations of 9°, 20°, 30°, 40° and 50°Brix was stored at 10°, 20° and 36°C for 16 weeks and sampled regularly for total soluble solids (TSS), pH, titratable acidity and ascorbic acid. No significant differences were found in the first two of these factors as a function of storage time. There was a small but significant decrease in citric acid concentration over 16 weeks. Ascorbic acid loss was greater at higher temperatures; at a constant temperature, the loss was smaller as TSS increased. Ascorbic acid degradation data fitted zero‐, first‐ and second‐order models equally well at all five TSS. Rate constants in 9°Brix juice were significantly higher than those for the other four concentrations at all three temperatures. Ea values of 47.8 and 24.1 kJ mol−1 were calculated for ascorbic acid degradation in 9° and 20°Brix juices. The effect of temperature far outweighed the effect of TSS on ascorbic acid degradation. Over the 16‐week storage period, maximum retention of ascorbic acid (95.7%) was obtained in the 50°Brix lemon juice concentrate stored at 10°C.

Water-Stress-Induced Changes in the Growth and Metabolism of Growing and Non-Growing Root Zones of Barley Seedlings

Experiments were conducted on 7-day-old barley (Hordeurn vulgare L. cv. KN 16) seedlings using polyethylene glycol (PEG-6000) to induce water stress. Growth, amount of PEG absorbed, and glucose, sucrose, free proline and organic acid contents were measured in growing (non-vacuolated) and non-growing (vacuolated) root tissues and shoots. Relative water content (RWC) and water potential were used to indicate the degree of stress. Lowering of RWC reduced growth and decreased the root : shoot ratio. Sugar content of the non-growing root zone changed with a pattern almost the reverse of that occurring in the growing root zone. The glucose level changed much more than the sucrose level in both growing and non-growing roots and shoots. Stress-induced proline accumulation was greater in the growing than in the non-growing root zones. The citric and malic acid contents increased in growing roots only above stress levels of -0.6 MPa. In growing roots, citric and malic acid concentrations began to decrease at - 0.35 MPa and - 0.8 MPa or lower stress levels, respectively. High water potential (-0.35 MPa) caused a decrease in malic acid concentration but low water potential (- 0.80 to - 0.89 MPa) caused a decrease in citric acid concentration in shoots.

温州ミカン果肉中の有機酸に及ぼす土壌の種類の影響

Effects of soils on the process and mechanism of organic acid formation in satsuma mandarin fruit were investigated.1. Citric acid concentration of the pulp was higher in fruit from the Tertiary rock soil than in fruit from the granite soil through the maturation period except late August. On the other hand, malic acid concentration of the pulp of Tertiary soil fruit was higher than that of granite soil fruit at an early stage of fruit growth. The concentrations of the fruits from both types of soils, however, became similar thereafter.As to the concentrations of the other minor organic acids, no effects of soils were found at any stage of the fruit maturation.2. The total amount of citric acid per fruit of the pulp of Tertiary soil fruits were higher than that of granite soil fruits. The stages at which the citric acid content was maximum were earlier in the granite soil fruits than in the Tertiary soil fruit. This finding shows that the granite soil brings about earlier fruit maturation. Malic acid content did not show any differences between the fruits from both types of soils at early stages of fruit development. No differences due to soil types were found for minor acid content.3. From the above results, it was concluded that the changes in the concentration and content of total organic acids in the pulp were due mainly to the change of citric acid. Thus, the effects of dilution due to fruit enlargement and also of the total amount of citric acid per fruit of the pulp on the concentration of citric acid were examined. As a result, the following two conclusions were obtained. (1) In July, when acid synthesis is most active, the daily increase in citric acid concentration due to the increase in synthesis of this acid is 30% higher in fruits from the Tertiary rock soil than in fruits from the granite soil. (2) In September, when the conversion of organic acid metabolism occurs, the total amount of citric acid per fruit of the pulp still increases in the Tertiary soil fruits, so that the daily decrease in citric acid concentration is smaller in Tertiary soil fruits than in the fruits from the granite soil. These two features may be the causes of the fact that the concentration of citric acid or the total amount of organic acids per fruit of the pulp remains high in the Tertiary soil fruit compared to that of granite soil fruit.