Degradation Of Tannins Research Articles

Histopathologic and ultrastructural findings in oak (Quercus spp.) toxicity on 2 beef cattle farms in Colorado.

Natural oak toxicity, a phenomenon sporadically reported in the United States, is due to consumption of any part of most oak trees (Quercus spp.). Ruminants, mainly cattle, are disproportionately susceptible to oak toxicity. Toxicity is attributed to degradation of the oak plant hydrolysable tannins by rumen microbes and enzymes into absorbable low-molecular-weight metabolites, which are postulated to bind and damage endothelial cells by unknown mechanisms. The clinical manifestations of acute toxicosis are nonspecific or broadly suggestive of renal disease due to acute tubular injury. Here we document the clinical, gross, histopathologic, and novel ultrastructural features of natural acute oak nephrotoxicity in 3 beef calves on 2 farms in Colorado, USA. Gross postmortem findings included perirenal edema with renomegaly and hemorrhagic gastroenteritis. Histologically, renal tubular epithelial necrosis was severe, with hemorrhage and intratubular hyaline casts. Transmission electron microscopy revealed extensive involvement of proximal and distal convoluted tubules, with predominantly intact basement membranes, and glomerular and interstitial endothelial injury and necrosis. The ultrastructural details of toxic nephropathy and vasculopathy induced by oak metabolites in natural cases of bovine oak toxicosis have not been described previously, to our knowledge.

Effect of tannin degradation of mangrove(Sonneratia alba) fruit on nutrient digestibility, protozoa population and methane gas production

Effect of tannin degradation of mangrove(Sonneratia alba) fruit on nutrient digestibility, protozoa population and methane gas production

Effects of Phytase and Tannase Enzyme Supplementation on in Vitro Nutrient Digestibility and Tannin Degradation of Sorghum-Based Broiler Diets

An in vitro study was conducted to assess the effects of phytase and tannase enzyme supplementation on nutrient digestibility and tannin degradability in sorghum-based broiler diets. A two-stage in vitro experiment involving simulation of gastric and ileal digestion in vivo was used. Data were analysed using Statistical Analysis System (SAS, 2011). The data were analysed for descriptive statistics and Chi-square tests were performed to check for possible associations among variables. Analysis of variance were performed to determine the effects of sorghum inclusion level as well as the effects of exogenous phytase and tannase supplementation on nutrients digestibility and tannin degradability using the GLM procedure. All tests were done at p<0.05 level of significance. The results of this study indicated that phytase and tannase supplementation significantly influenced calcium, phosphorus, fat and crude protein digestibility (p< 0.01). Sorghum inclusion level had no significant effect on calcium, phosphorus, fat and crude protein digestibility. Sorghum inclusion level significantly influenced tannin degradability (p<0.01). Chi-square test showed that there was an association between sorghum inclusion level and tannin hence increasing sorghum level increased tannin degradability. Both enzyme supplementation and sorghum inclusion level had significant effect on crude fibre and tannin degradability.

Production and Characterization of Natural Tannin-Degrading Aspergillus strains

Among the different types of agrowastes, tannin biomass also contributes to significant amount. The tannin rich biomass can be exploited as the most economic substrate for the production of industrially important enzyme Tannase. Tannases are hydrolases which find applications in different industries such as leather, food, feed, beverage and pharmaceutical industry. Tannases are gaining importance as industrially-important biocatalyst. The present study focuses on the isolation of natural tannin degrading fungal strains including their characterization. Among the fifty fungal cultures isolated from soil samples, eleven tannase producing isolates were selected by qualitative screening. The selected isolates were cultivated by liquid surface fermentation for quantitative estimation of extracellular tannase activity. On the basis of quantitative screening, two isolates Aspergillus niger and Aspergillus flavus were identified as efficient tannase producers. To study natural tannin degradation efficiency of the isolates, different tannin rich agro-residues were tested as carbon source in the production medium for tannase production as well as substrate for the enzyme. Both isolates utilized natural tannins appreciably, producing significant tannase yield. Gauva leaves and ber leaves proved to be the best carbon source for Aspergillus niger and Aspergillus flavus respectively. The optimum incubation period for maximum tannin utilization was found to be 72 hrs for Aspergillus niger and 96 hrs for Aspergillus flavus. In conclusion, both fungal isolates exhibited potential for tannin biomass utilization and conversion to various valuable industrial products.

Changing the polyphenol composition and enhancing the enzyme activity of sorghum grain by solid-state fermentation with different microbial strains.

Solid-state fermentation (SSF) has been widely used in the processing of sorghum grain (SG) because it can produce products with improved sensory characteristics. To clarify the influence of different microbial strains on the SSF of SG, especially on the polyphenols content and composition, Lactiplantibacillus plantarum, Saccharomyces cerevisiae, Rhizopus oryzae, Aspergillus oryzae, and Neurospora sitophila were used separately and together for SSF of SG. Furthermore, the relationship between the dynamic changes in polyphenols and enzyme activity closely related to the metabolism of polyphenols has also been measured and analyzed. Microstructural changes observed after SSF provide a visual representation of the SSF on the SG. After SSF, tannin content (TC) and free phenolic content (FPC) were decreased by 56.36% and 23.48%, respectively. Polyphenol oxidase, β-glucosidase and cellulase activities were increased 5.25, 3.27, and 45.57 times, respectively. TC and FPC were negatively correlated with cellulase activity. A positive correlation between FPC and xylanase activity after 30 h SSF became negative after 48 h SSF. The SG surface was fragmented and porous, reducing the blocking effect of cortex. Cellulase played a crucial role in promoting the degradation of tannin (antinutrient) and phenolic compounds. Xylanase continued to release flavonoids while microbial metabolism consumed them with the extension of SSF time. SSF is an effective way to improve the bioactivity and processing characteristics of SG. © 2024 Society of Chemical Industry.

Mass Transfer of Natural Dye Extraction and the Degradation Rate

This research studied the effect of temperature on the mass transfer rate and degradation rate of natural dye extraction. As the representative, two natural dyes extracted from Senduduk and Susupan Gunung plants were employed. Senduduk and Susupan Gunung are weed plants that are often found in peatlands. Susupan Gunung is easily found in South Kalimantan, and local people use it as a natural dye for handicraft products. Senduduk is often found in the South Sumatra area also used as a natural dye for traditional fabrics. Senduduk and Susupan Gunung were extracted in a three-neck flask using water as a solvent at temperatures of 50°, 70°, and 90°C. Samples of the extract solution were taken at certain times until the tannin concentration was constant. The tannin concentration in the solution was analyzed using volumetric methods. Experimental data consists of tannin concentrations in solution at various times. The mass transfer coefficient, equilibrium constant, and tannin degradation rate constant were determined by minimizing the sum square of errors between experimental data and the model. Senduduk contains more tannin (0.0094 g/cm3 solution) than Susupan Gunung (0.0079 g/cm3 solution), and Senduduk has a higher mass transfer coefficient than Susupan Gunung. The higher the temperature, the greater the rate of tannin degradation. During the extraction process, extract of Senduduk and Susupan Gunung leaves are stable at 50°C, which tends to degrade faster at higher temperatures.

Monitoring of Chemical and Fermentative Characteristics during Different Treatments of Grape Pomace Silage

Grape pomace is a fibrous food with satisfactory quantities of residual sugars. It meets the desirable characteristics for conservation in the form of silage for later use in animal feed, mainly for ruminant herbivores. Fresh grape pomace was subdivided into three treatment groups: grape pomace as a control, grape pomace treated with an inoculum of lactic acid bacteria, and grape pomace treated with zeolite. The treatments were performed in micro-silos over 90 days. There was a significant change (p < 0.05) in the chemical characteristics, content of biologically active compounds, and fermentative characteristics during the silage of all treatments. After 30, 60 and 90 days of ensiling, silages treated with inoculum and zeolite had better fermentation quality indicated by significantly (p < 0.05) lower pH and ammonia-nitrogen contents compared with those of the control. Also, the additives have decreased the total polyphenols and tannins for 97% in average which confirmed that lactic acid bacteria and zeolite positively effect on the degradation of polyphenols and tannins in grape pomace silage. The Flieg score was calculated and the values were above 80% what refers to excellent silage. In conclusion, our results suggest that inoculant and zeolite supplementation improves the quality of grape pomace silage for later use in animal feed.

Exogenous Melatonin Promotes Cold Tolerance in Grape Seedlings: Physiological, Transcriptomic, and Functional Evidence.

Melatonin (MEL) is an antioxidant molecule that enhances plant tolerance to environmental stress. However, the mechanisms by which MEL regulates cold signaling pathways in grapes under cold stress remain elusive. Here, we investigated the physiological and transcriptomic changes in grape seedlings treated with exogenous MEL to determine their protective role under cold stress. Results showed that 150 μM MEL effectively attenuated cold-induced cell damage by reducing reactive oxygen species (ROS) and preserving the chloroplast structure and function. MEL also inhibited tannin degradation, which contributed to its protective effect. Exogenous MEL promoted the synthesis of endogenous MEL, abscisic acid, auxin, and cytokinin while inhibiting gibberellin. Transcriptomic profiling revealed 776 differentially expressed transcripts in MEL-treated samples compared to controls. Functional analysis of a candidate hub gene, VvHSFA6b, showed that its overexpression in grape calli enhances cold tolerance by activating jasmonic acid synthesis pathway genes, promoting JA accumulation, and inhibiting JAZ-repressed transcription factors.

Biochemical investigations of polyphenol degradation enzymes in the phototrophic bacterium Rubrivivax gelatinosus.

Phloroglucinol (1,3,5-trihydroxybenzene) is an important intermediate in the degradation of flavonoids and tannins by anaerobic bacteria. Recent studies have shed light on the enzymatic mechanism of phloroglucinol degradation in butyrate-forming anaerobic bacteria, including environmental and intestinal bacteria such as Clostridium and Flavonifractor sp. Phloroglucinol degradation gene clusters have also been identified in other metabolically diverse bacteria, although the polyphenol metabolism of these microorganisms remain largely unexplored. Here, we describe biochemical studies of polyphenol degradation enzymes found in the purple non-sulfur bacterium Rubrivivax gelatinosus IL144, an anaerobic photoheterotroph reported to utilize diverse organic compounds as carbon sources for growth. In addition to the phloroglucinol reductase and dihydrophloroglucinol cyclohydrolase that catalyze phloroglucinol degradation, we characterize a Mn2+-dependent phloretin hydrolase that catalyzes the cleavage of phloretin into phloroglucinol and phloretic acid. We also report a Mn2+-dependent decarboxylase (DeC) that catalyzes the reversible decarboxylation of 2,4,6-trihydroxybenzoate to form phloroglucinol. A bioinformatics search led to the identification of DeC homologs in diverse soil and gut bacteria, and biochemical studies of a DeC homolog from the human gut bacterium Flavonifractor plautii demonstrated that it is also a 2,4,6-trihydroxybenzoate decarboxylase. Our study expands the range of enzymatic mechanisms for phloroglucinol formation, and provides further biochemical insight into polyphenol metabolism in the anaerobic biosphere.

Solid-State Fermentation of Green Tea Residues as Substrates for Tannase Production by Aspergillus niger TBG 28A: Optimization of the Culture Conditions

Tea (Camellia sinensis) is an evergreen shrub that is recognized worldwide for its functional properties. The current global production of green tea is approximately 5.3 million tons per year. Green tea processing has severely affected the generation of agro-industrial waste. One strategy for reducing waste accumulation is the revalorization of agro-industrial wastes via solid-state fermentation (SSF). The aim of this study was to valorize green tea processing residues to produce tannase under SSF using an endemic strain from Western Ghats, Aspergillus niger TBG 28A. SSF was performed in Erlenmeyer flasks with spent green tea leaves inoculated with spores of A. niger TBG 28A. Bioprocess optimization was carried out by employing the Box–Benkhen experimental design, achieving a high enzymatic yield of 246.82 (U/g). The present study shows the complexity of the degradation of tannins and the different patterns of expression of fungal tannase obtained from A. niger TBG 28 A. The enzyme was further purified to obtain a fold purification of 16.35% and a molecular mass of 150 kDa. Producing tannase with a novel strain of A. niger TBG 28A is an interesting strategy to revalorize green tea waste.

Anaerobic phloroglucinol degradation by Clostridium scatologenes.

Polyphenols are abundant in nature, and their anaerobic biodegradation by gut and soil bacteria is a topic of great interest. The O2 requirement of phenol oxidases is thought to explain the microbial inertness of phenolic compounds in anoxic environments, such as peatlands, termed the enzyme latch hypothesis. A caveat of this model is that certain phenols are known to be degraded by strict anaerobic bacteria, although the biochemical basis for this process is incompletely understood. Here, we report the discovery and characterization of a gene cluster in the environmental bacterium Clostridium scatologenes for the degradation phloroglucinol (1,3,5-trihydroxybenzene), a key intermediate in the anaerobic degradation of flavonoids and tannins, which constitute the most abundant polyphenols in nature. The gene cluster encodes the key C-C cleavage enzyme dihydrophloroglucinol cyclohydrolase, as well as (S)-3-hydroxy-5-oxo-hexanoate dehydrogenase and triacetate acetoacetate-lyase, which enable phloroglucinol to be utilized as a carbon and energy source. Bioinformatics studies revealed the presence of this gene cluster in phylogenetically and metabolically diverse gut and environmental bacteria, with potential impacts on human health and carbon preservation in peat soils and other anaerobic environmental niches. IMPORTANCE This study provides novel insights into the microbiota's anaerobic metabolism of phloroglucinol, a critical intermediate in the degradation of polyphenols in plants. Elucidation of this anaerobic pathway reveals enzymatic mechanisms for the degradation of phloroglucinol into short-chain fatty acids and acetyl-CoA, which are used as a carbon and energy source for bacterium growth. Bioinformatics studies suggested the prevalence of this pathway in phylogenetically and metabolically diverse gut and environmental bacteria, with potential impacts on carbon preservation in peat soils and human gut health.

The Addition of Red Dragon Fruit and Lemon Peels for the Improvement of Fermented Beverage Products

Coconut water is part of the coconut fruit, that has bioactive compounds that are thought to own high inhibitor activity to the presence of tannin compounds. However, this compound is antinutritional because it can interfere with macromolecule out there within the body. Considering chance of tannins, these parts are often reduced by fermentation techniques using lactic acid bacteria. This analysis aims to review the addition of dragon fruit and lemon peels in fermentation coconut water using lactic acid bacteria in order to reduce tannin levels and its potential capability as antioxidants. Coconut water fermented drink was prepared by fermentation technique using lactic acid bacteria with the addition of variations in mass of dragon fruit peel and lemon peel consisting of 5 treatments. The optimum conditions for fermentation of coconut water were determined from the decrease in tannin levels, total acid, and the highest total lactic acid bacteria. The optimum conditions for fermentation of coconut water were then tested using an HPLC instrument. Finally, the antioxidantactivity was tested using the FRAP (Ferric Reducing Antioxidant Power) method. The results showed that the addition of dragon fruit and lemon peels in fermented coconut water can reduce tannin levels, can increase total acid levels and the number of lactic acid bacteria formed in coconut water fermented drinks. The best proportion was obtained in the treatment of rasio of mass 1:2 resulted in the highest decrease in tannin content of 83.94 mg/100 g followed by a total acid value of 1.13% and the number of lactic acid bacteria was 8.4 × 107 CFU/mL. The HPLC chromatogram showed that fermented coconut water using lactic acid bacteria contained organic acid compounds such as lactic acid, acetic acid, and ascorbic acid. The highest antioxidant activity test was 82.37 mmgAAE/g. This study confirmed that the addition of dragon fruit and lemon peels affected the degradation of tannins and increased antioxidant activity during coconut water fermentation using lactic acid bacteria.

Comparative analysis of β-glucosidase activity in non-conventional yeasts.

The objective of this study was to evaluate the β-glucosidase activity in the non-conventional yeasts under cellulose, glucose and sucrose substrates. The participation of the enzyme β-glucosidase and its contribution to the enzymatic degradation of tannins is known. Within the classification of tannins are ellagitannins, molecules of gallic acid and ellagic acid, which are considered as nutraceutical compounds due to the properties that they present and that they can be used in the design of food and new drugs, synthesis of materials with antimicrobial capacity. The extracellular β-glucosidase activity was mainly presented in the Candida and Pichia strains, being the glucose and sucrose media the most capable for inducing the activity that showed maximum values with P. pastoris in glucose (0.1682±0.00 µmol/min mg protein), and C. utilis in cellulose (0.1129±0.1349 µmol/min mg of protein), and sucrose (0.0657±0.0214 µmol/min mg protein). Additionally, I. terricola and P. kluyvery stood out in a qualitative cellulose degradation approach measured by Congo red method (9.60±0.04 mm and 9.20±0.05 mm respectively). These indicate that P. pastoris and C. utilis have potential as β-glucosidase producers, especially when growing under complex carbon sources for biomass conversion, new biofuels production and polyphenol degradation with more manageable bioreactor process.

Antioxidative properties of bayberry tannins with different mean degrees of polymerization: Controlled degradation based on hydroxyl radicals

The antioxidant properties of condensed tannins (CTs) are closely related to the mean degree of polymerization (mDP), and CTs with low mDP show stronger antioxidant effects. Therefore, obtaining CTs with a low mDP are very meaningful in improving their antioxidant properties and utilization. In this study, hydroxyl radicals generated by the decomposition of hydrogen peroxide under UV irradiation were used to degrade bayberry tannins in a clean and controllable manner. Taking the formaldehyde reactivity as an index to control the mDP of the degradation product, the changes in antioxidant properties of bayberry tannins with different mDP were studied by the method of 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH), and 2,2-azido-di(3-ethyl-benzothiazole-6-sulfonic acid)diammonium salt (ABTS). Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), gel permeation chromatography (GPC), carbon nuclear magnetic resonance (13C NMR), and reversed-phase HPLC-ESI-MS were used to characterize the mDP, molecular weight (Mw), and chemical structure of the degradation products of bayberry tannins in different degradation stages. Results showed that hydroxyl radicals could cause significant degradation of bayberry tannins, and the controllable degradation of bayberry tannins could be achieved with the formaldehyde reactivity as an index. At the degradation times of 0, 2, 4, 6, and 8 h, the mDP (Mw) of the degradation products were as follows: 5.22 (2457), 4.36 (1895), 3.36 (1534), 2.87 (1153), and 1.78 (813), respectively. The antioxidant activity of the degraded product increased with the decrease in the mDP, and the degraded products had the largest formaldehyde reactivity and the best oxidation resistance when degraded for 6 h. This study provided a new method to achieve clean and controllable degradation of tannins and supported those tannins with low mDP could provide higher antioxidant activity.

Necrosis of Microcystis aeruginosa causing tannin derivatives in Rhus chinensis stem.

Algal infestation in Korean lakes, rivers, and in agroecosystems is a catastrophic problem resulting in contaminated drinking and agricultural irrigation water. Developing allelochemical-based algicides has previously faced difficulties, including dosage requirements and chemical instability. Despite these challenges, these algicides have enormous potential for eco-friendly use. This study presents the efficient use of tannin derivatives as antialgal chemicals modeled on a tannin-rich stem extract of Rhus chinensis in a thermal processing application. Tannic acids are the key component of algal necrosis in R. chinensis stem extract, and although heat extraction from the stem increased the crude extraction yield 1.8-fold, the procedure induced the conversion of tannic acids to gallic acid, resulting in lower antialgal activity. Gallotannin showed stronger antialgal activity (The 50% lethal dosage (LD50 )=44.6mg L-1 ) than gallic acid (LD50 =99.2mg L-1 ), and the nonheated extract exhibited 3.7-fold lower LD50 (0.66 g L-1 ) than the heated extract (LD50 =2.45 g L-1 ), resulting in 2.6-fold higher content of gallotannin. These results demonstrate that heat treatment of R. chinensis stems during the extraction process is not beneficial to algal control because of the acceleration of thermal tannin degradation, despite it showing higher crude extract yields. Therefore, it is suggested extraction processes minimizing the loss of tannic acids should be the preferred methods used to develop tannin-based natural algicides for controlling algal infestation. Tannic acids showed higher toxicity into necrosis of M. aeruginosa than gallic acid where heat-processed extraction of R. chinensis stems produces more gallic acid content resulting in thermal degradation of tannic complexes than the extraction of nonthermal treatment. © 2022 Society of Chemical Industry.

Date Seeds Flour Used as Value-Added Ingredient for Wheat Sourdough Bread: An Example of Sustainable Bio-Recycling.

Our study proposed date seeds flour (DSF) as an innovative ingredient for sourdough bread production through sustainable bio-recycling. We isolated autochthonous lactic acid bacteria and yeasts from DSF and DSF-derived doughs to build up a reservoir of strains from which to select starters ensuring rapid adaptation and high ecological fitness. The screening based on pro-technological criteria led to the formulation of a mixed starter consisting of Leuconostoc mesenteroides, Lactiplantibacillus plantarum, and Saccharomyces cerevisiae strains, which allowed obtaining a mature type I sourdough after consecutive refreshments, in which an aliquot of the durum wheat flour (DWF) was replaced by DSF. The resulting DSF sourdough and bread underwent an integrated characterization. Sourdough biotechnology was confirmed as a suitable procedure to improve some functional and sensory properties of DWF/DSF mixture formulation. The radical scavenging activity increased due to the consistent release of free phenolics. Perceived bitterness and astringency were considerably diminished, likely because of tannin degradation.

Characterization of historical leather bookbindings by various thermal methods (TG/MS, Py-GC/MS, and micro-DSC) and FTIR-ATR spectroscopy

The goal of this study was to obtain information about the thermal stability, composition and molecular structure of four historical leather bookbindings dated between the 17th and 19th century and to identify correlations between their thermal, structural and chemical properties and deterioration mechanisms by using thermal analysis and decomposition methods (TG/MS, micro-DSC, Py-GC/MS), and infrared spectroscopy (FTIR-ATR). The TG/MS study revealed that the maximum thermal decomposition rate of the historical samples depended on the deterioration degree of leather. Micro-DSC was applied to determine the collagen population profile, i.e., “leather-like”, “parchment-like”, or “gelatin-like” behavior, which characterizes the deterioration pattern of the samples. The historical samples have higher amount of adsorbed water compared with the modern leather indicating their higher polarity. The significantly higher yield of carbon dioxide during the pyrolysis of historical leathers demonstrates that leather underwent various oxidation processes over time. The smaller yield of the pyrolysis products attributed to vegetable tannins detected in the chromatograms of historical leathers was related to the degradation of tannins (i.e., de-tanning), while the higher amount of 2-pyrrolidone and succinimide confirmed the oxidation of proline and hydroxyproline amino acid residues in the historical leathers. Leather de-tanning and collagen gelatinization were clearly evidenced by both micro-DSC and FTIR-ATR.

Polysaccharide hydrolyzing enzyme activity of bacteria, native to Apis florea gut

Introduction and Aim: Apis florea commonly known as “dwarf honey bee” harbors enormous gut bacteria that can digest complex carbohydrates and other food components. In this regard, the present investigation was focused on analyzing the polysaccharide degrading ability of bacteria isolated from the gut of honeybee, for their possible application in nutraceutical and pharmaceutical industries. Materials and Methods: Nine bacterial isolates were screened for carbohydrate degrading enzymes viz., amylase, pectinase, cellulase, tannase and laccase, using respective substrate by plate assay method. Further activities of amylase and pectinase were measured quantitatively by dinitrosalicylic acid (DNS) method. Results: All the nine selected isolates exhibited amylase and pectinase activities. However, only two isolates exhibited lignolytic and cellulolytic activity. None of the isolates showed tannin degradation. Maximum amylase activity (4.95 U/mg) was observed in Bacillus halotolerans af-M9 followed by Klebsiella oxytoca af-G4 (4.62 U/mg). With respect to pectinase activity Klebsiella pneumoniae af-E17 displayed higher activity (0.24 U/mg) followed by Klebsiella oxytoca af-G4 (0.20 U/mg). Conclusion: Habitat-specific innovations are being explored for novel compounds for therapeutic applications. This study throws a light on selection of carbohydrate degrading bacteria from a new source i.e., GUT of honeybee.

UV light-driven controlled photodegradation of condensed tannins from larch bark

Photocatalytic degradation of condensed tannins is a more efficient and cleaner way than traditional microbial and chemical degradations. In this work, the ultrasonic-assisted UV light-driven controlled degradation of larch tannins was studied, in which the effects of nano-TiO2 dosage and tannin concentrations on the degradation efficiency were investigated systematically. The structure and molecular weight of photocatalytic degradation products were characterized by time-of-flight mass spectrometry, gel permeation chromatography, and infrared spectrum. Results showed that the controlled photocatalytic degradation of condensed tannins could be achieved by controlling the formaldehyde reactivity of the degradation products. The optimized condition was reached when the tannin concentration was 4%, the nano-TiO2 catalyst load was 0.2%, and the degradation time was 5 h. Under these conditions, the condensed tannins of larch bark were mainly degraded to dimers, with formaldehyde reactivity reaching as high as 0.7931. Photocatalytic degradation can be a new method for the degradation of condensed tannins.

Sensory evaluation and storage stability of fat reduced shortdough biscuit using hydrolysable tannin encapsulated double emulsion as fat replacer

The aim of this study was to assess the organoleptic acceptability and storage stability of formulated fat reduced shortdough biscuit with hydrolysable tannin encapsulated double emulsion as fat replacer. The sensory acceptability of the biscuit samples was evaluated by using fuzzy logic and quantitative descriptive analysis. Primarily, none of the fat replaced samples showed astringency due to the presence of hydrolysable tannin. The 40% fat replaced shortdough biscuits was perceived best in accordance to the sensory attributes. The shelf life of the biscuits was obtained as 98 days considering moisture adsorption to be the limiting factor for safe storage. The degradation of hydrolysable tannins was modelled into zero order (Radj2 = 0.969) and first order kinetics (Radj2 = 0.995) that exhibited good fit with the experimental data. There was no significant change in colour; however, the hardness of shortdough biscuits decreased owing to the change in moisture content during storage. The low value of zero order and first order kinetics constant revealed slow rate of degradation for hydrolysable tannin in the shortdough biscuits. Thus, the developed fat reduced shortdough biscuits are healthier alternatives as compared to the control, possessing functional properties, without imparting undesirable flavour from hydrolysable tannin.