Removal Of Tannins Research Articles

Determination of phenolics and proteins causing sediment formation in pomegranate juice using “Tannase+Lactonase” and “Protease”

In this study, pomegranate juice (PJ) was treated with “tannase+lactonase [human-derived (H-PON-1) or rabbit-derived (R-PON-1)]” or “protease [aspartic protease (AP) or cysteine protease (CP)].” After treatment, effects of tannins, proteins and amino acids on sediment formation were determined during storage at 20℃. Among proteins, prolamin showed the highest effect in PJ treated with “tannase+H-PON-1/R-PON-1” and CP. While amino acids did not affect sediment formation in “tannase+H-PON-1/R-PON-1” or AP treatments, only glycine increased sediment content in CP treatment. Removal of galloyl and/or HHDP groups from HHDP-galloyl-glucose-isomer, pedunculagin-2 and punigluconin by “tannase+H-PON-1/R-PON-1” was very effective in preventing sediment formation. Prolamin:galloyl glucose isomer ratio and HHDP-galloyl-hexoside-2 and HHDP-galloyl-glucuronide contents should be 23.244±1.162 and, 1.254±0.063 and 0.679±0.034 mg/L to prevent sediment, respectively. Since common parameters preventing sediment formation in both methods that target removal of tannins and/or proteins were punigluconin content and prolamin:punicalagin-2 ratio, these two parameters must also be considered in sediment-free PJ production.

Effect of the membrane processing on tannin removal from soluble fraction of Persian gum

SummaryTannins, which are known as anti‐nutrient compounds with capability of limiting proteins and minerals bioavailability, are present in Persian gum. Ultrafiltration (UF, polysulfone membrane, 30 and 90 kDa, 1, 2 and 5 bar) and nanofiltration (NF, polysulfone, 400 Da, 2.5 and 5 bar) were used to remove tannin from the soluble fraction of Persian gum. The results revealed that the highest amount of tannin removal was achieved in UF (5 bar) and NF (5 bar). However, the use of the membrane process significantly decreased the apparent viscosity of the permeate, which might have an undesirable effect on the functionality of the gum. The effects of membrane molecular weight cut‐off, feed temperature, ultrasound pre‐treatment, feed concentration and pH, on the amount of tannic acid reduction, and changes in permeate flux, volume concentration factor difference, tannin reduction efficiency, and permeate apparent viscosity were evaluated. The results showed that total tannin removal efficiency was increased by ultrasound pre‐treatment, reduction of feed pH, and higher membrane molecular weight cut‐off. Increasing the feed temperature and concentration enhanced the apparent viscosity of permeate, although its value was lower than the control sample.

Tannin removal from Persian gum and investigation of physicochemical properties: Comparing different methods

Persian gum (PG) is a novel natural exudate gum and the main challenge regarding PG is tannin content of gum which limits its application in food and pharmaceutical industries. In fact, tannins are known as anti-nutrient compounds because they limit bioavailability of proteins and minerals. Hence, in this study, the effect of microwave radiation (180, 450, 600 W for 5 min), autoclaving (121 °C for 20 min), boiling (5, 10 and 15 min) and soaking either in water or saline solutions (mono- and divalent salts) was evaluated to remove tannins from Persian gum. Moreover, the effect of tannin removal on the physicochemical properties was investigated by evaluation of rheological properties (flow behavior and viscoelastic tests), zeta potential and Fourier transform infrared spectroscopy (FTIR) data. Our outcomes demonstrated that the highest tannin removal efficiency found to be 75.67 ± 0.25, 74.32 ± 0.54 and 67.08 ± 0.19 % which belonged to soaking in water (180 min), soaking in CaCl2 solution (1% w/v, 90 min) and boiling (15 min) treatments of brownish PG granules, respectively (p < 0.05). Interestingly, removal of tannin increased apparent viscosity of PG dispersion. Based on oscillatory tests, boiling treatment caused exhibition of solid-like behavior, in contrast to control sample. Tannin removal reduced zeta potential and the lowest reduction belonged to the gums soaked in water (from -32.3 to -28.7 mV); however, formation of ion-bridging in the presence of CaCl2 caused a remarkable decrease. FTIR analysis declared that in the boiled sample, a decrease was detected in vibration intensity within the range of 3200–3500 cm−1 (-OH groups) which can be due to heat degradation. Findings of the present research confirmed that soaking in water is a low-cost and practical method for tannin removal of PG, which almost had no negative effect on physiochemical properties of gum.

Evaluating polyphenol and ascorbic acid contents, tannin removal ability, and physical properties during hydrolysis and convective hot-air drying of cashew apple powder

Abstract Cashew apple is a source of by-products in the cashew industry. Powder products provide convenience to the process of use, transport, and preservation of nutrients. In this study, the production of soluble powder from cashew apples was developed through the investigation of hydrolysis process (time, temperature, and enzyme tannase) and convective drying conditions (temperature and maltodextrin content). The following indicators are evaluated, such as the total polyphenol content (TPC), total tannin content, total ascorbic acid, solubility, turbidity, and color. The results have shown that TPC increased by 1.67 times, and more than 50% of tannins was removed after the hydrolysis process. At the same time, the efficiency of the process over 30% under all processing conditions was evaluated. These results are the foundation for the development of cashew apple powder and related products, thereby improving the economy of the cashew industry in Vietnam and the world.

Valorization of faba bean peels for fungal tannase production and its application in coffee tannin removal

This study describes the optimization of the production conditions of Penicillium commune tannase on unutilized food waste, green bean peels, using the central composite of the response surface methodology. It also focuses on applying purified tannase to reduce tannins in coffee. The proposed design recommended a temperature of 29.07 °C, pH of 6.74, a tannin level of 6.76%, and 3.31% bean peels for maximum tannase production (313.40 U/g/min) by solid-state fermentation. This waste can be used as a sustainable and low-cost substrate for tannase enhancement by ≈5 folds. Applying purified tannase in instant coffee beverage resulted in a ≈ 23% reduction in tannins and a ≈ 16% increase in reducing sugars, with no significant changes in caffeine and phenolic compound contents. Tannase had a detrimental effect on the volume and stability of the coffee foam. This study will pave the way for tannase industrial production and its promising use in low-bitter coffee production.

Exergoeconomic analysis of ultrasound-assisted extraction of tannins from acorn fruit

Acorn fruit (AF) is a valuable yet tannin-rich forest byproduct. The removal of bitter-tasting tannins is essential for its use as food. This study investigated exergoeconomic analysis of ultrasound-assisted extraction (USAE) with varying amplitudes (20%-60%-100%) and duty cycle conditions (20%-60%-100%) to extract tannins from AF. Conventional solvent extraction (CSE) was used as comparison. AF, mixed with water (1:10 w/v), subjected to ultrasound until tannin content reached 0.0274 mg TAE/mg DM. The study evaluates process conditions' impact on performance and tannin's unit extraction cost. Exergoeconomic analysis was conducted by considering the exergy values, operating costs, investment costs, and extraction time. CSE requires 300 min for target tannin content, while USAE reduces this time to 40-fold. The highest energy efficiency (84.44 ± 2.97) and exergy efficiency (83.68 ± 3.61) were determined at 20% amplitude-20% duty cycle. USAE reduces extraction costs by 25% compared to CSE. USAE has the potential for rapid tannin extraction and cost reduction.

Removal of Tannins from Cashew (Anacardium Occidentale l.) Apple Juice in Binh Phuoc (Viet Nam) by Using Enzymatic Method

Objective: The study was conducted to identify the optimum condition for maximum tannin removal in cashew apple juice by enzymes. Tannin is the cause of astringency and reduces sensory value, which lead to underestimating the by-product of the cashew nut industry. The result of the study will help to utilize and convert cashew apples into a nutritious juice product, contributing to zero waste life and sustainable food production. Method: The study was conducted by examining the parameters of the detannying process by tannase enzyme and tannase combined with pectinase. The parameters for tannase adding are juice pH (4 – 6), incubation time (40 min – 160 min), temperature (25 – 45oC) and enzyme concentration (0.1 – 0.4%). Regarding combinations of tannase and pectinase, pectinase concentration was examined in the range of 0.6 – 1.2%. Result: The combination of pectinase 0.8% and tannase 0.2%, 80 minutes of incubation, 35oC at juice pH (4.61) can remove tannin up to 56.09%. Conclusion: Using the combination of pectinase and tannase in tannin removal from cashew apple juice has shown high efficiency, which can reduce the astringency in this fruit and apply in juice processing, contributing to zero waste agricultural production.

POTENT ANTIBACTERIAL EFFECTS OF TERMINALIA SUPERBA ENGL. AND DIELS (COMBRETACEAE) BARK EXTRACTS

Antibiotic misuse has caused widespread multi-resistance in Enterobacteriaceae. Our study investigates Terminalia superba (T. superba) extracts against Extended-spectrum beta-lactamases (ESBL)-producing strains. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined using broth microdilution (Mueller-Hinton, 106 CFU/mL). The extract concentrations ranged from 0.078 to 80 mg/mL. We evaluated T. superba extracts β-lactamase inhibition of nitrocefin hydrolysis, estimated inhibition percentages, and IC50 values for each extract. The double-disk test confirmed the presence of ESBLs in the strains, as all of them exhibited hydrolytic activity. The results indicated that the T. superba extracts displayed dose-dependent inhibitory effects on beta-lactamase. Among them, the hydro-ethanolic extract displayed potent inhibitory activity against β-lactamases produced by ESBL-E. coli (IC50 = 0.065 mg/mL), ESBL-K. pneumoniae (IC50 = 0.076 mg/mL), and ESBL-P. mirabilis (IC50 = 0.082 mg/mL). However, following the removal of tannins, the hydro-ethanolic extracts anti-β-lactamase activity was reduced. Our findings highlight the remarkable in vitro activity of T. superba extracts against ESBL-producing Enterobacteriaceae, suggesting their potential clinical utility in addressing infections caused by these drug-resistant pathogens. The exploration of T. superba extracts as a possible source of effective anti-ESBL agents could contribute significantly to combating antibiotic resistance.

Tannin Removal of Cashew Apple Juice by Powdered Gelatin Treatment and Its Utilization in Bacterial Cellulose Production.

In this study, cashew apple juice was treated with different levels of powdered gelatin (2%, 5%, and 10%) to remove tannins. The results showed that the addition of 5% gelatin removed 99.2% of condensed tannins while did not affect reducing sugars of juice. Subsequently, tannin-free cashew apple juice (CA) was aerobically fermented for 14days with Komagataeibacter saccharivorans strain 1.1 (KS) and Gluconacetobacter entanii HWW100 (GE) in comparison with Hestrin-Schramm (HS) medium as control. The dry weight of bacterial cellulose (BC) obtained from the KS strain (2.12 and 1.48g/L for CA and HS media, respectively) was higher than that from the GE strain (0.69 and 1.21g/L for CA and HS media, respectively). Although GE showed low BC production yield, its viability in both media after 14-day fermentation was notable (6.06-7.21 log CFU/mL) compared to KS strain (1.90-3.30 log CFU/mL). In addition, the XRD and FT-IR analysis showed that there was no significant difference in the crystallinity and functional groups of BC films when cultured on CA and HS medium, while the morphology by SEM exhibited the phenolic molecules on the film surface. Cashew apple juice has been shown to be a viable and cost-effective medium for the BC production.

Insight on tannin content inhibition to amylase hydrolysis of acorn nut flour to glucose and the protein-substitute sacrifice strategy

Acorn nut flour (ANF) is universally considered as a feasible and alternative non-food starchy feedstock for fermentation industries, with an annual production of over 2 million tons in China, while it contains around 7.17% tannin content with potential effective inhibition to enzyme proteins involved in the common amylase hydrolysis of starch to fermentable glucose. Compared with corn and potato starch, the obvious damping and inhibitory rate was experimentally detected with at least 35% decline during the enzymatic hydrolysis of ANF. This decline was completely resolved by the extraction and removal of tannin from ANF, or by improving α-amylase loading; meanwhile, the return and addition of extracted tannin markedly weakened α-amylase liquefaction of varied starchy feedstocks. These data provided a solid evidence for acorn nut tannin bio-inhibition to α-amylase hydrolysis of ANF. Bovine serum albumin (BSA) and milk protein successfully substituted α-amylase as sacrifice-proteins that resolved effectively the tannin bio-barrier to α-amylase hydrolysis of ANF, and improved the enzymatic hydrolysis and glucose yield to over 86%. Finally, the common and cost-effective milk protein substitute was recommended, providing the technical guidance for new food-substitute bioresources and acorn-based industry.

Efficient removal of tannins from anaerobically-treated palm oil mill effluent using protein-tannin complexation in conjunction with electrocoagulation

Despite the significant removal of chemical oxygen demand (COD) by anaerobic digestion, anaerobically-treated palm oil mill effluent (POME) still contains tannins and other phenolic compounds, resulting in residual COD and a brownish color. In this study, we investigated the removal of tannins from anaerobically treated POME using protein-tannin complexation in conjunction with electrocoagulation. The amino acid composition of the protein, aqueous pH, and protein: tannin ratios were found to be important parameters affecting the tannin removal efficiency. Pig blood protein was superior to casein protein in removing tannins, possibly because it had aspartic acid as the major amino acid component. At an optimal condition with a pig blood protein: tannin ratio of 0.33 (w/w), a current density of 30 mA/cm2, pH 5, and an electrolysis time of 10 min, the removals of tannins, COD, and color were 93%, 96%, and 97%, respectively.

Removing tannins and debittering brewer’s spent yeasts by Tween 80

Introduction: Yeast extract from brewer's spent yeast cells is a promising nutrition source for many applications in the food industry and biomass production. However, because of the impurities that cause the bitter and astringent flavor attributed to hop resins during fermentation, brewer's spent yeasts in the industry have not been widely used. Contaminants have been withdrawn by using a variety of techniques. However, most reported methods have focused on removing iso-alpha acid rather than tannin, which has anti-digestive and antimicrobial properties. This study focuses on removing tannins and evaluating their impact on reusing brewer's spent yeast in biomass production. Methods: In this work, Tween 80 was employed for the removal of tannins and other bitter substances from brewer’s spent yeasts. In addition to biochemical approaches, the efficiency of cultivating probiotics with autolysates from yeasts cleaned by various buffers is used to evaluate the effectiveness of eliminating tannins and bitter compounds. Results: In tannin removal, the outstanding efficiency of Tween 80 was four times higher than that of water and hypotonic 0.5% NaCl solution. The debittering efficiency increases from 77% to 83.6% by using Tween 80. Therefore, the cell density of Lactobacillus fermentum 4C cultures with the autolysate from Tween 80-treated spent yeast cells increased by 16.5% and 10.2% compared to that of cultures washed with distilled water or 0.5% NaCl, respectively. The autolysate of Tween 80-treated yeast cells is rich in protein and α-amino nitrogen. It shows advantages in culturing different strains of probiotics. Conclusions: By skipping the first stage of biomass creation, the reuse of spent yeasts in the production of yeast extracts will not only address environmental issues but also have a positive economic impact.

Antioxidant and anticancer activities of Annona muricata L. and Antidesma bunius L. leaves, and molecular networking analysis using LC-MS/MS metabolomics

Several natural products are known to have anticancer activity, which helps prevent cancer. This study explores the potential use of different extracts of Annona muricata L. and Antidesma bunius L. leaves as an anticancer drug by testing its anti-oxidative and anticancer properties. Furthermore, metabolomics of these plant extracts was performed to characterize them. This project studied the bioactivities and phytochemistry of plants found in Mt. Makiling, Philippines. Hexane, ethyl acetate, and methanol leaf extracts of Annona muricata L. (Guyabano) and Antidesma bunius L. (Bignay) were screened for their anticancer and antioxidant properties. Extracts of each plant species were subjected to a clean-up procedure (removal of tannins and chlorophyll) and were analyzed using the same tests as the crude. The growth inhibitory effect against A-549 human lung carcinoma cells was determined using MTT assay, while the total antioxidant activity was determined using DPPH assay. All extracts exhibited both anticancer and antioxidant activity of varying degrees. Ethyl acetate crude extract of Annona muricata L. showed the highest percent growth inhibition against lung cancer cells, while methanol crude extract of Antidesma bunius L. showed the highest total antioxidant activity. The effect of the clean-up procedure varied per extract; some exhibited an enhanced activity while others exhibited a decreased activity upon clean-up. The extracts’ responses to free radicals and lung cancer cells can be attributed to phytochemicals like alkaloids, indoles, and phenols identified using qualitative phytochemical tests and LC-MS/MS analysis. Results suggest that Annona muricata L. and Antidesma bunius L. leaf extracts are potential anticancer and antioxidant agents.

Comparing the efficiency of six clearing methods in developing seeds of Arabidopsis thaliana

Key messageClearSee alpha and FAST9 were optimized for imaging Arabidopsis seeds up to the torpedo stages. The methods preserve the fluorescence of reporter proteins and seed shape, allowing phenotyping embryos in intact seeds.Tissue clearing methods eliminate the need for sectioning, thereby helping better understand the 3D organization of tissues and organs. In the past fifteen years, clearing methods have been developed to preserve endogenous fluorescent protein tags. Some of these methods (ClearSee, TDE, PEA-Clarity, etc.) were adapted to clear various plant species, with the focus on roots, leaves, shoot apical meristems, and floral parts. However, these methods have not been used in developing seeds beyond the early globular stage. Tissue clearing is problematic in post-globular seeds due to various apoplastic barriers and secondary metabolites. In this study, we compared six methods for their efficiency in clearing Arabidopsis thaliana seeds at post-globular embryonic stages. Three methods (TDE, ClearSee, and ClearSee alpha) have already been reported in plants, whereas the others (fsDISCO, FAST9, and CHAPS clear) are used in this context for the first time. These methods were assessed for seed morphological changes, clearing capacity, removal of tannins, and spectral properties. We tested each method in seeds from globular to mature stages. The pros and cons of each method are listed herein. ClearSee alpha appears to be the method of choice as it preserves seed morphology and prevents tannin oxidation. However, FAST9 with 60% iohexol as a mounting medium is faster, clears better, and appears suitable for embryonic shape imaging. Our results may guide plant researchers to choose a suitable method for imaging fluorescent protein-labeled embryos in intact Arabidopsis seeds.

Comparing carriers as a support media of white-rot fungi in natural tannins removal

• The growth of white-rot fungi was tested on polyethylene carriers containing cellulose; • Basidiomycetes could cover fully the carriers with the highest cellulose percentage; • B. adusta could grow up to 60% of carrier surface in not-sterile conditions; • B. adusta growth was associated with 25±4% Quebracho tannin sCOD removal; • B. adusta and A. tubingensis could grow together and remove Quebracho sCOD up to 15±4% In the last decades, White-rot Fungi bioremediation potential has been widely investigated, providing remarkable results toward several recalcitrant molecules. However, full-scale applications based on fungi are not employed yet and little is known about their optimal operating conditions, such as i) their ability to grow without sterile conditions, ii) co-substrate requirements and iii) the accurate carrier design for fungal growth. In this study, several batch tests were performed as preliminary steps to evaluate the possible design of a pilot-scale reactor based on fungal biomass to be operated under not-sterile conditions in the removal of Quebracho natural tannin. The tests were performed to verify fungal affinity, including Basidiomycetes and Ascomycetes for innovative cellulose-containing carriers compared to commonly employed PolyUrethane Foam Cubes. In particular, four fungi, including three Basidiomycetes White-rot Fungi, Bjerkandera adusta, Phanerochaete chrysosporium and Tyromyces chioneus and the Ascomycota strain Aspergillus tubingensis , were employed. As a first step, fungi were tested to evaluate their ability to attach and grow onto 12 types of innovative carriers made by High-Density PolyEthylene and containing cellulose in different percentages. Other tests were performed without sterile conditions. In particular, fungal abilities i) to attach and grow onto two different types of support, including cellulose-containing carrier and polyurethane foam cubes and ii) to biotransform recalcitrant molecules (Quebracho natural tannin) iii) to grow and operate synergistically in a consortium of two fungi, were evaluated. The main parameters evaluated were soluble Chemical Oxygen Demand (sCOD) reduction and dry weight increase. Basidiomycetes showed high affinity for cellulose-containing carrierswith the highest cellulose percentage (7%) achieving full colonization and 60% coverage, in sterile conditions and not- sterile conditions, respectively. These results were associated with a Quebracho sCOD removal of 25±4%, without sterility. When combined, the two selected strains, Bjerkandera adusta and Aspergillus tubingensis were able to grow on carriers and to remove up to 15±4% of tannins recalcitrant sCOD. This study provides evidence of i) Basidiomycetes high affinity for cellulose-containing carriers that could favour fungi attachment in sterile and not-sterile conditions, t .and ii) the feasibility of a combined use of Ascomycetes and Basidiomycetes in bioremediation.

Study on Cutting Cultivation Technology and Rooting Mechanism of Cyclocarya paliurus

Abstract Cyclocarya paliurus is an important rare and multipurpose tree species in China. In view of the difficulty of asexual propagation of Cyclocarya paliurus, this paper explores the technical system of Cyclocarya paliurus cutting propagation from the aspects of cutting collection position and time, tannin removal pretreatment, hormone treatment, sand storage treatment, cutting matrix, environmental factors and physical factors, and discusses its internal physiological changes in the process of cutting rooting. This paper attempts to clarify the physiological characteristics of Cyclocarya paliurus in the process of cutting propagation and rooting. The results of this study can provide technical support and theoretical basis for the cuttings propagation of Cyclocarya paliurus. The results show that the rooting rate of cuttings inserted on the mixture of perlite and vermiculite is up to 32.2 %. In summer, when the middle and upper parts of branches were treated with 300 mg/L rooting powder No. 1 and GGR-6 (Green Growth Regulator-6) mixture, the rooting rate was up to 44.4 %; in winter, the rooting rate of the base of branches was 36.7 % under the same treatment. During the rooting process of Cyclocarya paliurus, a large number of nutrients such as soluble sugar, starch and soluble protein were consumed. SOD (Superoxide Dismutase), POD (Peroxidase), and PPO (Polyphenol oxidase) are closely related to cutting and rooting. High activity SOD and POD are conducive to the expansion of cuttings, and high activity SOD and PPO are conducive to improving the stress resistance of cuttings. Hormone treatment can improve the enzyme activity and make the enzyme activity change in the direction conducive to rooting. The change of endogenous hormone content in cuttings reflects the rooting ability of Cyclocarya paliurus. Substrate heating and hormone treatment can regulate the content of endogenous hormone in cuttings during the rooting process, so as to affect the rooting effect, the stable total nitrogen content in cuttings was conducive to root formation.

Effectiveness of Tannin Removal by Alkaline Pretreatment on Sorghum Ethanol Production

Sorghum has been proposed as a complement or replacement for corn in ethanol production. One difference between sorghum and corn is the presence of tannins, which may affect enzymatic activity. High-tannin sorghum hybrid XM217 was used to analyze the effect of tannin removal by the alkaline pretreatment of sorghum for ethanol production. A laboratory-scale dry-milling process was used on treated sorghum/corn blends to generate mash that was fermented by Saccharomyces cerevisiae and then compared to a 100% untreated sorghum control. Cellulase was added to a similar set of mash to determine the feasibility of the tannin-removal treatment as a pretreatment method for cellulosic ethanol production. Theoretical ethanol yield increased from 68.2 ± 1.5% to 78.5 ± 2.5% for alkaline-pretreated sorghum vs. untreated sorghum, with a corresponding increase in mean ethanol concentrations from 8.02 ± 0.15 to 9.39 ± 0.26% w/v. The average theoretical ethanol yield increased from 69.8 ± 1.7% to 94.6 ± 1.9% when using cellulase with untreated and treated sorghum. The use of alkaline tannin removal resulted in a significant increase in the theoretical ethanol yield obtained when using 100% sorghum, when compared to the theoretical ethanol yield obtained when using 100% corn. The combination of cellulase and alkaline tannin removal improved the yield of ethanol in all cases compared to the experiments without cellulase.

Comparing Carriers as a Support Media of White-Rot Fungi in Natural Tannins Removal

Comparing Carriers as a Support Media of White-Rot Fungi in Natural Tannins Removal

Soaking and germination procedures actually impact polyphenols, tannins, and phytate contents in some Egyptian pulses

Whereas the nutritional value of pulses is generally recognized, the presence of antinutritional elements in their composition limits their use. Effect of soaking and germination process on removal or reducing of (total phenolic, tannins and phytic acid) content of commonly consumed pulses in Egypt were studied. Four pulses namely faba bean (Vicia Faba) Giza 843, chickpea (Cicer arietinum) Giza 1, cowpea (Vigna unguiculata) krymy 7 and soybean (Glycine max) Giza 111 were used in this research. The total phenolic compounds, tannins, and phytic acid content of four pulses were significantly decreased after soaking for 12 hours and germination treatment for varied periods (24, 48, and 72 hours). On a dry weight basis, the phenolic compounds content of raw pulses was 370.9, 132.5, 763.4, and 249.4 mg/100g, for faba bean, chickpea, cowpea, and soybean respectively, while tannin content was 684.5, 488.1, 390.9, and 225.5 mg/100g, and phytic acid content was 1050.6, 719.2, 987.2, and 1076.2 mg/100g. Soaking for 12 hours significantly decreased the concentration of total phenolics, tannins and phytic acid contents of the investigated pulses by 4.0-22.7%, 7.1-26.5% and 7.0-15%, respectively. Germination process for 72 hours reduced total phenolics, tannins and phytic acid contents of studied pulses by 21.4 -56.9%, 23.9-64.8% and 54.6-65.0%, respectively. From the obtained results it could be concluded that the reduction of antinutritional factors content was increased with the progress of both soaking and germination periods in all studied pulses.

Nutrient requirement of tannery wastewater containing tannins

Biological wastewater treatment methods are extensively used in the treatment of industrial effluents among which Activated Sludge Process (ASP) holds a prominent position. To carry out the degradation of organic matter, the micro-organisms present in the activated sludge need sufficient amount of nutrients and oxygen in the aerobic treatment process. Hence, this study was undertaken to assess and optimize the nutrient requirement in the treatment of vegetable tanning process wastewater (VTW) generated from tanneries. The characterization of VTW revealed that the observed Biochemical Oxygen Demand (BOD):Nitrogen (N):Phosphorus (P) ratio of VTW was 100:1.42:0.07, which is deficient in both N and P. Aerobic reactor study was conducted with BOD:N:P ratio of 100:1.42:0.07, 100:5:0.1, 100:5:1, 100:5:3 and 100:5:5 separately. For N:P of 5:0.1, removal efficiencies of BOD 5 , COD and tannin were 49.0 %, 37.3 % and 30.2 %, respectively, whereas, for N:P of 5:3, BOD 5 ,COD and tannin removal efficiency was 59.7 %, 50.9 % and 38.0 %, respectively. However, further increasing the N:P ratio to 5:5, BOD 5 ,COD and tannin removal efficiencies were 60.9 %, 51.2 % and 38.7 %, respectively. It was observed from the results that for N:P ratio of 5:3 to 5:5, the improvement in removal efficiencies was marginal. Hence, BOD:N:P ratio of 100:5:3 was considered as optimum Respirometry study revealed that oxygen uptake was 62.5 mg O 2 during the 24 h and 18 % of MLSS growth was observed. From modified Stover–Kincannon model the kinetic constants U max of 3.74 g/L day and K B of 54.08 g/L.d were arrived at; The k value was obtained from first order and zero order equation was 16.95 mg/L h −1 and 0.026 h −1 , respectively for tannin as substrate for the optimized ratio BOD:N:P ratio of 100:5:3. This study emphasizes that proper balance of N and P is needed for synthesis of sufficient biomass for degradation in biological treatment.