Total Organic Acid Content Research Articles

Comparative study of phytochemicals and antioxidant potential of wild edible mushroom caps and stipes

A comparative study of the organic acids and phenolics composition and of the total alkaloids content of entire wild edible mushrooms (Russula cyanoxantha, Amanita rubescens, Suillus granulatus and Boletus edulis) and correspondent caps and stipes was performed. All species presented oxalic, citric, malic and fumaric acids, with A. rubescens exhibiting the highest total organic acids content. Organic acids were preferably fixed in the cap. Among phenolics, only p-hydroxybenzoic acid was found in A. rubescens and S. granulatus, in very low amounts. B. edulis was the species that presented the highest total alkaloid amounts. Except for this species, alkaloids mainly accumulated in the cap. All of the species exhibited a concentration-dependent scavenging ability against DPPH·. B. edulis revealed the highest antioxidant capacity. The cap seemed to be the part with highest antioxidant potential. Some relationships between chemical composition and antioxidant capacity were considered.

Overpressure retardation of organic acid generation and clastic reservoirs dissolution in central Huanghua Depression

Abstract There exist overpressures in the Paleogene of the central Huanghua Depression, Bohai Bay Basin, and the hydrocarbons of deep zones are dominantly accumulated in secondary pores of the overpressure formations. The diagenetic physical simulating experiments were done at different temperatures and under 25 Mpa and 55 Mpa, respectively to study the relationships between the overpressures and the organic acid generation in mudstones and the dissolution of reservoirs. The residual total organic acid contents in the samples under 25 MPa are lower than those under 55 MPa at the same temperatures, whereas the generated total organic acids contents under 25 MPa are higher than those under 55 MPa, suggesting that pressure retards the organic acid generating. The porosity data from the different pressure settings also supports the results. The main secondary porosity zone of Well GS48 with overpressures is 580 m deeper than that of Well QN2 with no overpressure; overpressures retard the organic acids generation and result in the delay of reservoirs dissolution. The hydrocarbon exploration in deep basins should be focused on the over-pressured formations.

Comparison of lactic acid contents between dried and frozen tarhana

The lactic acid content of tarhana produced with different dough treatments was determined. Trials were performed to see the effects of different parameters on organic acid produced during fermentation. In these trials, fermentation time, yogurt content and preservation method parameters were varied. Increasing fermentation time had a significant effect on lactic acid formation as well as total organic acid content of tarhana ( p < 0.01). In the samples of tarhana with 50% yogurt, total acidity increased 29.9% in the first 48 h of fermentation. During the subsequent 48 h the increase was only 3.6%. Lactic acid increased 17.7% during the first 48 h followed by an increase of 3.1% during the next 48 h of fermentation in these same samples. On the other hand, when yogurt content was increased from 50% to 75%, total acidity in the first 48 h was 17.0% greater than the samples with 50% yogurt. There was also a 20.2% increase in lactic acid as well. The highest acidity and lactic acid levels were determined in the samples using 75% yogurt. Yogurt level had a significant effect on all the analytic parameters ( p < 0.01). However, it is possible that increasing the amount of yogurt to this level would cause technological problems because of the increase in water and fat contents. Of the two preservative methods utilized in this study, sun drying produced higher organic acid (1.97 g/100 g) and lactic acid (1.29 g/100 g) levels than samples that were frozen (1.64 g/100 g; 1.06 g/100 g, respectively). Preservative methods had a significant effect on moisture, total acidity, lactic acid ( p < 0.01) and oil ( p < 0.05) content of tarhana.

Changes in extractive components and microbial proliferation during fermentation of fish sauce from underutilized fish species and quality of final products

To make use of underutilized fish species and produce high-quality condiments substitutable for those of mammalian origin, fish sauces were produced on a small industrial scale from three fish species, the flyingfish Cypselurus agoo agoo, the small dolphinfish Coryphaena hippurus, and the deepsea smelt Glossanodon semifasciatus, using salt and koji mold. During 180 days of fermentation, the pH decreased to approximately 4.5 and total nitrogen and free amino acids increased to approximately 2 g/100 mL and 6000 mg/100 mL, respectively. Halophilic and extreme halophilic bacterial counts dramatically increased from 106 to 108 colony forming units/mL between days 14 and 30 and decreased the reafter. In the final products, the pH and salt concentration decreased to between soy sauce and a Vietnamese fish sauce, Nuoc mam. The total amino acid and organic acid contents were almost the same as those of Nuoc mam and soy sauce. Sensory evaluation found these products to have lower smell, saltiness, and bitterness, and higher sweetness and umami taste than Nuoc mam. During fermentation, the histamine content increased in one or two of three fermentation tanks for each fish species. As a result, the histamine content of the final products was higher than that in Nuoc mam.

Screening of Antioxidant Compounds During Sprouting of Brassica oleracea L. var. costata DC

The changes in antioxidant compounds of Brassica oleracea L. var. costata DC seeds were monitored during the first twelve days of seedling development. Sprouts were screened at time intervals of two days for phenolic compounds and organic acids. The identified phenolic compounds included esters of sinapic acid with glucose, gentiobiose and kaempferol, as well as sinapoylcholine. The organic acids were oxalic, aconitic, citric, pyruvic, malic, shikimic, and fumaric acids. During germination, a depletion of phenolic compounds was observed, although no qualitative changes were seen. Among individual compounds, kaempferol, choline and glucose esters of sinapic acid showed a marked decrease between days two and six, whereas the changes in gentiobiose esters of sinapic acid were smaller. The total organic acids content increased rapidly during the first four days, with less significant variations thereafter. Malic acid, the major organic acid found in sprouts, greatly contributed to this result though oxalic, pyruvic, and fumaric acids also increased in the same manner. In contrast, aconitic, citric and shikimic acids showed decreases between days two and twelve of germination.

Changes in Crested Wheatgrass Root Exudation Caused by Flood, Drought, and Nutrient Stress

Root exudates can chelate inorganic soil contaminants, change rhizosphere pH, and may increase degradation of organic contaminants by microbial cometabolism. Root-zone stress may increase exudation and enhance phytoremediation. We studied the effects of low K+, high NH4+/NO3- ratio, drought, and flooding on the quantity and composition of exudates. Crested wheatgrass (Agropyron cristatum) was grown in Ottawa sand in sealed, flow-through glass columns under axenic conditions for 70 d. Root exudates were collected and analyzed for total organic carbon (TOC) and organic acid content to compare treatment effects. Plants in the low K+ treatment exuded 60% more TOC per plant per day (p = 0.01) than the unstressed control. Drought stress increased cumulative TOC exuded per gram dry plant by 71% (p = 0.05). The flooded treatment increased TOC exuded per gram dry plant by 45%, although this was not statistically significant based on the two replicate plants in this treatment. Exudation from the high NH4+/NO3- ratio treatment was 10% less than the control. Exudation rates in this study ranged from 8 to 50% of rates in four other published studies. Gas chromatography-mass spectrometry (GC-MS) analysis indicated that malic acid was the predominant organic acid exuded. Fumaric, malonic, succinic, and oxalic acids were also detected in the exudates of all treatments. These results demonstrate that nutrient and water stress have significant effects on the quantity and composition of root exudates. Cultural manipulations to induce stress may change the quantity of root exudates and thus increase the effectiveness of phytoremediation.

Organic Acids of Commercial Beers in China: A Chemometric Study

The concentration of six organic acids (acetic acid, lactic acid, pyruvic acid, malic acid, citric acid, and succinic acid) and pH were determined in 45 beer samples (23 from China and 22 from other countries) with the intention of associating the “moderate to very sour” character of Chinese local beers with particular acids. The content of acetic, lactic, and total organic acids in Chinese lagers was significantly higher, while citric acid was much lower, than that of foreign brands (P < 0.05). Using discriminant analysis, both stepwise and with all variables included, moderately strong classifications were obtained using the magnitude of the original gravity (low, medium, and high), the origin of the beer (Chinese or foreign), and the sourness intensity (slightly, moderately, and very sour) as the classification categories. These analyses supplied more information about organic acids in beer and its associated effect on the properties of lager beer.

Response of Neotyphodium lolii-infected perennial ryegrass to phosphorus deficiency

It has been demonstrated that endophyte-infected (EI) ryegrass performed better in response to N deficiency than its endophyte-free (EF) counterpart. When P is considered, there is a lack of related information. In this study, &lt;i&gt;Lolium perenne&lt;/i&gt; L. infected with &lt;i&gt;Neotyphodium lolii&lt;/i&gt; was employed to establish EI and EF populations. Soil-grown EI and EF ryegrass were tested for their responses to P deficiency. The results showed that the endophyte infection improved the adaptability of ryegrass to P deficiency. When P was limited, EI roots were significantly longer (EI, 398.8; EF, 323.4 m/pot) and heavier (EI, 30.58; EF, 23.20 g/pot) than EF roots; the root: shoot ratio of EI plants was greater than that of EF plants (&lt;i&gt;P&lt;/i&gt; &lt; 0.05). The content of total phenolics and organic acids was significantly greater for EI roots than for EF roots at low P supply; the concentration of both, however, was not improved by the endophyte infection. This suggested that it was the higher root dry weight (DW) that contributed to the higher content of total phenolics and organic acids for EI plants, and the endophyte infection might have negligible effects on chemical modification of perennial ryegrass. Endophyte infection did not increase P uptake rate but did significantly improve P use efficiency of ryegrass in response to P deficiency (EI, 0.734; EF, 0.622 g DW/mg P).

Perioperative Synbiotic Treatment to Prevent Postoperative Infectious Complications in Biliary Cancer Surgery

Use of synbiotics has been reported to benefit human health, but clinical value in surgical patients remains unclear. To investigate the effect of perioperative oral administration of synbiotics upon intestinal barrier function, immune responses, systemic inflammatory responses, microflora, and surgical outcome in patients undergoing high-risk hepatobiliary resection. Patients with biliary cancer involving the hepatic hilus (n = 101) were randomized before hepatectomy, into a group receiving postoperative enteral feeding with synbiotics (group A); or another receiving preoperative plus postoperative synbiotics (group B). Lactulose-mannitol (L/M) ratio, serum diamine oxidase (DAO) activity, natural killer (NK) cell activity, interleukin-6 (IL-6), fecal microflora, and fecal organic acid concentrations were determined before and after hepatectomy. Postoperative infectious complications were recorded. Of 101 patients, 81 completed the trial. Preoperative and postoperative changes in L/M ratio and DAO activity were similar between groups. Preoperatively in group B, NK activity, and lymphocyte counts increased, while IL-6 decreased significantly (P < 0.05). Postoperative serum IL-6, white blood cell counts, and C-reactive protein in group B were significantly lower than in group A (P < 0.05). During the preoperative period, numbers of Bifidobacterium colonies cultured from and total organic acid concentrations measured in feces increased significantly in group B (P < 0.05). Postoperative concentrations of total organic acids and acetic acid in feces were significantly higher in group B than in group A (P < 0.05). Incidence of postoperative infectious complications was 30.0% (12 of 40) in group A and 12.1% (5 of 41) in group B (P < 0.05). Preoperative oral administration of synbiotics can enhance immune responses, attenuate systemic postoperative inflammatory responses, and improve intestinal microbial environment. These beneficial effects likely reduce postoperative infectious complications after hepatobiliary resection for biliary tract cancer.

High oxygen combined with high carbon dioxide improvesmicrobial and sensory quality of fresh-cut peppers

The effects of high O 2 and high CO 2 throughout storage on the microbial and sensory quality of fresh-cut bell peppers from two commercial ‘California’ cultivars grown under different climatic conditions were studied. The ‘Meteor’ cultivar was minimally processed in Leuven (Belgium) and the ‘Requena’ cultivar in Cartagena (Murcia, Spain). The storage conditions were (kPa O 2/kPa CO 2/kPa N 2) 100/0/0, 80/15/5, 60/0/40, 50/15/35, 20/15/65 and 21/0.03/≅79 as control. Bell peppers freshly-cut in cubes were stored at 5 °C up to 9–10 days. Changes in total counts of mesophilic, psychrotrophic, yeasts and mould as well as Enterobacteriaceae were monitored. Individual and total sugars and organic acids contents, visual appearance, color, shriveling, off-aroma, crunchiness, flavor and overall quality were also evaluated. The results in both experiments showed that 80 or 50 kPa O 2 combined with 15 kPa CO 2 maintained the main sensory quality attributes and inhibited growth of the spoilage microorganisms and Enterobacteriaceae in minimally processed bell peppers.

(173) Phytonutrient Accumulation and Antioxidant Capacity at Eight Developmental Stages of Black Raspberry Fruit

To investigate phytonutrient accumulation in black raspberries, fruits of `Jewel' and `MacBlack' were harvested at stages from the onset of color development (S1) to ripe fruit (S7). S1–S7 samples were characterized for color reflectance and then frozen at –28 °C within an hour of harvest. Additional ripe fruit were maintained at 20 °C for 3 days to overripen (S8) before freezing. After storage, samples were analyzed for dry weight (DW), total soluble solids (TSS), fructose (FRU), glucose (GLU), and organic acid (ORG) contents; total phenolic (PHE) and anthocyanin (ACY) contents; individual cyanidin glycoside levels (ICG); and antioxidant capacity (FRAP and ABTS) by standard methodology. `Jewel' and `MacBlack' ripened similarly. Chroma values and DW percentage decreased while TSS levels, sugar contents (FRU+GLU), PHE, ACY, the ACY: PHE ratio, and ICG increased with progressive ripening stages (S1–S7). Values of PHE, ACY, and ICG were highly correlated (r &lt; +0.95) with FRAP and ABTS values. ACY levels in S6 fruit were 18% to 23% less than those of S7; lower S6 ACY levels were associated with reduced antioxidant capacity in `MacBlack', but not `Jewel'. Overripened fruit (S8) exhibited increased DW (11% to 25%) and decreased sugar contents (16% to 17%), consistent with moisture and respiratory losses after harvest. After correction for these losses, S7 and S8 levels of PHE, ACY, FRAP, and ABTS were similar in `MacBlack'. However, as `Jewel' overripened, ACY levels and antioxidant activity increased 44% and 22% to 26%, respectively. Our data suggests that significant changes in the antioxidant behavior of black raspberries can occur during the periods surrounding peak ripeness.

Effects of phenylalanine fermentation byproduct and sugarcane molasses on fermentation quality and rumen degradation of whole crop barley (Hordeum vulgare L.) silage in situ

AbstractPhenylalanine fermentation byproduct (PFB) is generated by purifying phenylalanine products from microbial fermentation in the food industry. We examined the function of PFB as an ensiling agent to improve the silage fermentation and nutritive value of forage crops. We investigated the fermentation quality and rumen degradability of whole crop barley (Hordeum vulgare L.) silage in situ. We ensiled this type of silage in a laboratory scale using five compositional ratios (v/v) of PFB (20%, 40%, 50%, 60% and 80%) and a mixture of sugarcane molasses (SCM). Controls included the same volumes of water as the mixture of sugarcane molasses. The following strains Lactococcus lactis ssp. lactis (IFO12007), Leuconostoc mesenteroides ssp. mesenteroides (IFO12060), Lactobaccillus plantarum (IF014713), Pedioccocus acidilactici (IFO3858), Clostridium butyricum (IFO3858) and silage yeast (strain MY; separated from whole crop rice silage in this laboratory) were cultivated at 30°C in the recommended media containing a substituted carbon source depending on the compositional ratios of PFB and SCM mixtures. The growth of these strains was determined by measuring the optical density at 600 nm (OD600). The growth of the lactic acid bacteria significantly (P &lt; 0.001) increased in the presence of all PFB additives as compared with the control. The growth of C. butyricum was significantly increased, whereas that of silage yeast was decreased under all conditions. The concentrations of lactate and total organic acids were significantly higher (P &lt; 0.001) whereas those of acetate were lower in all PFB silages. These results indicated that PFB improved the silage fermentation of forage crops. With leaf and stem fractions, the neutral detergent fiber (NDF) content was significantly (P &lt; 0.001) decreased by the PFB additive and the rumen degradability of DM and NDF in situ was also significantly increased (P &lt; 0.01 and P &lt; 0.001, respectively).

Effects of dietary inclusion of triticale, rye and wheat and xylanase supplementation on growth performance of broiler chickens and fermentation in the gastrointestinal tract

An experiment was performed over a period of 5 weeks with 576 one-day-old cockerels (Cobb 500), which were randomly divided into 6 experimental groups (12 replicate cages with 8 birds/cage). The objective of the experiment was to estimate whether different grain types (wheat, rye or triticale) and exogenous xylanase inclusion influence the performance and the gastrointestinal ecosystems of broiler chickens as regards intestinal viscosity, pH as well as the concentration of short-chain fatty acids (SCFA) and lactic acid (LA). The rye-based diets resulted in the poorest production results followed by wheat and triticale-based diets. Ileal viscosity decreased in the range: rye (140 cps), triticale (6.1 cps) and wheat (2.5 cps). Xylanase supplementation reduced ileal viscosity significantly only in birds fed with rye. The cereal type influenced the fermentation process in the broiler gastrointestinal tract more than the xylanase supplementation. The total concentration of organic acids was highest in the caeca, followed by the crop, ileum and gizzard. Lactic acid concentrations were highest in the content of the crop followed by ileum, gizzard and caeca. Propionate was only detected in caecal contents, whereas butyrate was also found in small amounts in the contents of the crop of birds from all treatments. The concentrations of acetate, butyrate and total organic acid concentration in caecal contents of chickens receiving the rye-based diets were lower than in birds fed the other cereals (P<0.001). Enzyme supplementation reduced the relative weight of the caeca in rye-fed birds (P=0.001).

Comparative effects of exopolysaccharides from lactic acid bacteria and fructo-oligosaccharides on infant gut microbiota tested in an in vitro colonic model with immobilized cells

The aim of this study was to compare the effects of purified exopolysaccharides from Lactobacillus rhamnosus RW-9595M with those of a well-known prebiotic (short-chain fructo-oligosaccharides) on infant colonic microbiota using a new three-stage chemostat model with immobilized infant faecal microbiota. Two continuous cultures with different faecal inocula were tested with different compositions of carbohydrate media. During the first fermentation (F1), fructo-oligosaccharides tested at a concentration of 9.8 g L(-1) increased the number of lactobacilli and decreased coliforms both in gel beads and in effluent from all three reactors, in agreement with data from the literature. During the second fermentation (F2), the effect of fructo-oligosaccharides tested at a lower concentration (7.5 g L(-1)) was reduced compared with F1. Fructo-oligosaccharides also increased total organic acid concentration and decreased ammonia production. Results obtained for exopolysaccharide tested at 1.5 g L(-1) indicate that exopolysaccharides from L. rhamnosus RW-9595M was not metabolized by infant microbiota and lacked any prebiotic effect.

Modified atmosphere packaging preserves quality of SO 2-free ‘Superior seedless’ table grapes

‘Superior seedless’ table grapes were stored for 7 days at 0 °C followed by 4 days at 8 °C + 2 days at 20 °C under modified atmosphere packaging (MAP). Two polypropylene films (PP) were used to generate the MAP, the micro-perforated PP-30 and an oriented PP (OPP). The OPP film was applied with and without fungicide (10 μL of trans-2-hexenal or 0.4 g Na 2S 2O 5 kg −1). As control a macro-perforated PP was used. PP-30 packages reached the lowest O 2 and the highest CO 2 levels. Control clusters showed the highest weight losses and decay while almost no losses occurred under MAP treatments. No changes in softness, skin and/or pulp browning, or cluster shatter were found. After shelf life MAP-treated clusters showed slight to moderate stem browning, except under SO 2 where practically no browning occurred while control clusters showed an extreme stem browning. After shelf life, MAP treatments showed good visual appearance and crunchiness, while control fruits were unmarketable. No off-flavors were detected for MAP treatments except for hexenal-treated berries. No remarkable changes for color, firmness, soluble solids content, pH, titratable acidity and maturity index were detected. Total sugars content at harvest was 200 g L −1 and only slight decreases were found after shelf life for most treatments. Total organic acids content at harvest was 15.4 mg 100 mL −1, which remained quite constant after cold storage and shelf life. The main phenolic compounds were flavan-3-ols (over 85% from the total content), hydroxycinnamic acid derivatives and flavonols, whose total amount at harvest was 140 mg kg −1 in a fresh weight basis. After shelf life only slight decreases in total phenolics occurred in all treatments. As a main conclusion, SO 2-free MAP kept the overall quality of clusters close to that at harvest, with few differences when SO 2 was added.

Altered Gut Flora and Environment in Patients with Severe SIRS

The gut is considered an important target organ of injury after severe insult such as sepsis, trauma, and shock. The impact of bacterial translocation or mesenteric lymph on systemic inflammatory response and multiple organ damage has been investigated in animals, but dynamic changes in the gut flora and environment have not been fully clarified in critically ill patients. In the present study, we quantitatively evaluated changes in the gut microflora and environment in patients with severe systemic inflammatory response syndrome (SIRS). Twenty-five patients with severe SIRS, who fulfilled the criteria for SIRS, had a serum CRP level >10 mg/dL, and were treated in the intensive care unit for more than 2 days, were included in our study. SIRS was a result of sepsis in 18 patients, trauma in 6, and burn in 1. A fecal sample was used for quantitative evaluation of microflora (bacterial counts of 10 key groups including Bifidobacterium and Lactobacillus) by plate or tube technique and of the gut environment (pH and 9 organic acids by high speed liquid chromatography). Data obtained from patients were compared with corresponding data from healthy volunteers. Analysis of fecal flora confirmed that patients with severe SIRS had significantly lower total anaerobic bacterial counts (especially 2-4 log fewer "beneficial" Bifidobacterium and Lactobacillus) and 2 log higher "pathogenic" Staphylococcus and Pseudomonas group counts than those of healthy volunteers. Concentrations of total organic acids (especially "beneficial" short-chain fatty acids such as acetic acid, propionic acid, and butyric acid) in the feces were significantly decreased in the patients, whereas pH was markedly increased. The gut flora and environment are significantly altered in patients with severe SIRS. Abnormal gut flora and environment may affect systemic inflammatory response after severe insult.

Determination of 'unmeasured' anions in acidotic ICU patients

Metabolic acidosis is one of the most frequent acid-base disorders occurring in the ICU. Major causes of metabolic acidosis in critically ill patients are hyperchloremia, hyperlactatemia and the presence of anions of unknown identity, the so-called 'unmeasured' anions. The latter is associated with increased mortality and several diseases: sepsis, shock, liver dysfunction and renal failure. The physicochemical approach described by Stewart can be applied to quantify metabolic acidosis. Accordingly, the strong ion gap (SIG) is a quantitative measure of 'unmeasured' anions. We hypothesised that derangements in amino acid and organic acid metabolism and abnormal uric acid concentrations could be an explanation for the SIG. From 32 adult ICU patients with metabolic acidosis, defined as a pH less than 7.35 and a base excess less than -5 mmol/l, the SIG was calculated in a single arterial blood sample. Two groups were compared: patients with SIG 5 mEq/l. 'Unmeasured' anions were examined quantitatively by ion-exchange column chromatography, reverse-phase HPLC and gas chromatography/mass spectrometry measuring, respectively, 25 amino acids, uric acid and organic acids. Some organic acids were determined semi-quantitatively. The Mann–Whitney U test was applied for significance (considered P < 0.05) in all cases. For nominal data, the chi-square test was used. Aspartic acid, isoleucine, ornithine, uric acid, succinic acid, fumaric acid, p-OH-phenyllactic acid and the semi-quantified organic acids 3-OH-isobutyric acid, pyroglutamic acid and homovanillic acid were all significantly elevated in the SIG >5 group (n = 12, mean = 8.3 mEq/l) compared with the SIG 5 group who was in a prolonged fasted state at ICU admission, 3-OH-butyric acid was extremely high: 4.0 mEq/l, corresponding to 25% SIG. Overall, the averaged difference between both groups in total amino acid, uric acid and organic acid concentration contributed to the SIG for, respectively, 3.5% (268 μEq/l, not significant), 2.2% (169 μEq/l, P = 0.021) and 1.0% (79 μEq/l, P = 0.025). The total organic acid concentration consisted of glycolic acid, oxalic acid, methylmalonic acid, succinic acid, fumaric acid, malic acid, adipic acid and p-OH-phenyllactic acid. Comparison of patient characteristics of both groups showed that age, sex, APACHE II score, pH, base excess and lactate were not significant. However, renal insufficiency, sepsis and mortality were more prominent in the SIG >5 group. Also, the apparent strong ion difference (due to a significantly lower plasma chloride), phosphate and urea were significantly elevated in the SIG >5 group. This study demonstrates that total amino acids, uric acid and organic acids form a minor contribution (6.8%, corresponding to 517 μEq/l) to the SIG in acidotic ICU patients.

Organic acids in two Portuguese chestnut ( Castanea sativa Miller) varieties

The organic acids composition of two different chestnut ( Castanea sativa Miller) varieties (Judia and Longal) were determined by HPLC/UV. In order to check the influence of the processing over these compounds, samples treated in three distinct manners (roasted, boiled and fried) were also analysed. The results showed that chestnut is characterized by the presence of seven organic acids: oxalic, cis-aconitic, citric, ascorbic, malic, quinic and fumaric acids. The organic acid quantitative profile allows the distinction of the two varieties. Longal variety samples presented higher organic acids contents than those from Judia variety. The contents of the pair malic plus quinic acids may be useful for the discrimination of the two varieties. Roasting, boiling and frying procedures lead to significant reduction of total organic acids contents.

Influence of controlled-pH and uncontrolled-pH operations on recombinant benzaldehyde lyase production by Escherichia coli

To select the host microorganism having the highest benzaldehyde lyase (BAL) production capacity, pUC18∷ bal gene was transferred into four Escherichia coli strains. As the highest enzyme activity was obtained with E. coli K12 (ATCC 10798) carrying pUC18∷ bal gene, BAL production medium was designed for K12. Using the designed medium containing 8.0 kg m −3 glucose, 5.0 kg m −3 (NH 4) 2HPO 4 and the salt solution, the effects of uncontrolled-pH and controlled-pH operations were investigated at uncontrolled-pH pH UC 7.2 and controlled-pH values pH C 5.0, 6.4, 6.7, 7.0, 7.2 and 7.8 in 3.0 dm 3 bioreactor systems with a V R = 1.65 dm 3 working volume at the air inlet rate of Q o/ V R = 0.5 vvm and agitation rate of N = 500 min −1. The uncontrolled-pH (pH UC 7.2) operation produced the highest cell concentration and BAL activity as C X = 2.3 kg m −3 and A = 860 U cm −3, respectively. Among the controlled-pH operations, the highest cell concentration and enzyme activity were obtained at pH C 7.0 operation, respectively, as C X = 2.1 kg m −3 and A = 775 U cm −3. The accumulation of the metabolic by-product acetic acid and the total organic acid concentrations were the highest at pH C 7.2 and 7.8 operations. On the other hand, there was no significant difference in the acetic acid concentration profiles of pH C 5.0, 6.4, 6.7 and 7.0 operations; however, the highest total organic acid concentration was attained at pH C 5.0 because of the lactic acid excretion, and the lowest total organic acid was obtained at pH C 6.7. K L a values varied between 0.01 and 0.03 s −1. To compare the mass transfer and biochemical reaction rates, the maximum possible oxygen utilization rate, possible mass transfer rate, Damköhler number, and effectiveness factor, were also calculated. Damköhler number increased with the cultivation time indicating that mass transfer resistances were becoming more effective than biochemical reaction resistances. The yield and maintenance coefficients as well as the kinetic constants for BAL production process were also reported.

The effect of level and type of cereal non-starch polysaccharides on the performance, nutrient utilization and gut environment of pigs around weaning

The influence of non-starch polysaccharides (NSP) level and solubility on performance, digestion site and gut environment was investigated in 20 Swedish Yorkshire litters between 3 and 9 weeks of age. The litters were distributed among five diets based on cereals and cereal by-products. The control diet (C) had a medium content of NSP (147 g/kg dry matter (DM)), whereas diets H and Hi had a high content of NSP (188–250 g/kg DM), and diets L and Li had a low content of NSP (95–109 g/kg DM) after dilution with starch. The proportion of insoluble (i) NSP was higher in diet Hi and Li (0.80–0.85) than in diets C, H and L (0.68–0.73). The pigs offered diet Li showed the highest (P<0.05) feed intake and grew faster (P<0.05) than pigs offered diets C, L and H. In the post-weaning period feed:gain was highest for pigs offered the C and H diets and lower for pigs offered the low NSP diets and diet Hi. During week 6, the coefficient of caecal (CCAD) and total tract (CTTAD) apparent digestibility of organic matter (OM) was lower (P<0.05) in diet Hi compared to the other diets, and the CCAD and CTTAD of crude protein (CP) was higher (P<0.05) in diet L compared to the high NSP diets. During week 7, the CCAD and CTTAD of OM was lower (P<0.05) in diet Hi compared to the low NSP diets and diet C. The CCAD of CP and starch was higher (P<0.05) in diet L compared to the control diet. Diet L showed higher (P<0.05) values of digestible energy compared to the high NSP diets, both in the 6 and 7 weeks old piglets. NSP solubility influenced (P<0.05) the caecal digestibility of arabonixylans and total NSP in the 6 and 7 weeks old piglets, as well as the caecal digestibility of total dietary fibre in the 7 weeks old piglets. The content of total organic acids (OA) was linearly related to the pH level at the ileum ( R 2 = 0.70), caecum ( R 2 = 0.57) and colon ( R 2 = 0.83). The experimental diets altered the molar proportions of lactic acid and short chain fatty acids (SCFA), of total OA, as well as the molar proportions of acetic, propionic and butyric acids, of total SCFA, in the stomach, ileum, caecum and colon of the piglets. In conclusion, NSP solubility influenced the digestibility of cell wall polysaccharides at the caecum but not at the total tract. Diet Hi promoted production of lactic acid in the stomach and small intestine and butyric acid in the large intestine.