Pharmacological and Toxicological Appraisal of Promising Enzyme-tyrosinase Isolated from Soil Bacteria-an Update

Aims: The membrane associated tyrosinase is an enzymatically active monomeric glycoprotein which is purified to only a low degree. It has gained importance in the present era due to its antioxidant and immunomodulatory properties as well as applications in industry. Moreover its role in the synthesis of melanin in skin for protection from UV radiations also paved the way towards the better understanding of this enzyme. Study Design: Biochemical and molecular characterization of tyrosinase producing soil bacterium had been followed by the assessment of its antioxidant, cytotoxic and anti-cancer activities. Place and Duration of Study: Whole work had been completed at the Microbiology and Molecular biology labs of IMBB during 2018- 2019. Methodology: Tyrosinase producing species were identified by biochemical characterization followed by their genomic DNA sequencing and BLAST analysis while crude tyrosinase was characterized by Bradford's methods, tyrosinase activity and total protein activity, followed by their molecular characterization on SDS-PAGE. The antioxidant and free radical scavenging properties of tyrosinase were evaluated via DPPH, ABTS and FRAP assays and cell proliferation inhibition and the cytotoxicity was calculated via antitumor and MTT assays. Results: P. putida, B. cereus, B. mycoides, M. luteus, K. pneumonia were found to be tyrosinase producing species while their SDS-PAGE analysis showed that the molecular mass of crude tyrosinase was about 39 kDa. Protein contents, total tyrosinase and specific tyrosinase activity was found to be highest in tyrosinase from B. mycoides [0.008±0.06 mg/ml, 1500±0.06 U/ml and 346820.8±0.03 U/mg of tyrosinase respectively]. The results of biological activities of crude tyrosinase vary from bacteria to bacteria. Tyrosinase from P. putida showed higher antioxidant [66.4±0.01% in DPPH assay, 32.04±0.06%in ABTS assay and 320.6±0.06 in FRAP assay], antitumor [67.8±0.01%] and cytotoxic activity [39±1.0% cell viability], followed by B. Cereus tyrosinase [64.7±0.06% antioxidant power in DPPH assay, 53.41±0.03% in ABTS assay and 159.6±0.06% in FRAP assay, 46.46±0.01% antitumor and 43±0.75% cell viability]. Conclusion: The study revealed that tyrosinase isolated from different bacterial strains depicted optimal percentage of anti-oxidative, anti-proliferative and cellular viability and can be used in the near future for medical and industrial purposes.

Download Full-text

Approach to Optimization of FRAP Methodology for Studies Based on Selected Monoterpenes

Molecules ◽

10.3390/molecules25225267 ◽

2020 ◽

Vol 25 (22) ◽

pp. 5267

Author(s):

Karolina A. Wojtunik-Kulesza

Keyword(s):

Biological Activities ◽

Tween 20 ◽

Plant Metabolites ◽

Frap Assay ◽

Antioxidant Power ◽

Secondary Plant Metabolites ◽

Reduction Activity ◽

High Volatility ◽

Ferric Reducing Antioxidant Power ◽

Analgesic Activities

Terpenes, wide-spread secondary plant metabolites, constitute important parts of many natural compounds that hold various biological activities, including antioxidant, calming, antiviral, and analgesic activities. Due to their high volatility and low solubility in water, studies of compounds based on terpenes are difficult, and methodologies must be adjusted to their specific characteristics. Considering the significant influence of iron ions on dementia development, the activity of terpenes in reducing Fe3+ represents an important area to be determined. Previously obtained results were unreliable because ferric-reducing antioxidant power (FRAP) methodology was not adjusted regarding studying terpenes. Taking this fact into account, the aim of this study was to optimize the method for monoterpene assessment. The study included three modifications, namely, (1) slightly adjusting the entire FRAP procedure, (2) replacing methanol with other solvents (heptane, butanone, or ethyl acetate), and (3) adding Tween 20. Additionally, a thin layer chromatography (TLC) -FRAP assay was performed. The obtained results revealed significant improvement in the reduction activity of selected terpenes (linalool, α-phellandrene, and α-terpinene) in studies with Tween 20, whereas replacing methanol with other solvents did not show the expected effects.

Download Full-text

Assessment of Volatiles and Polyphenol Content, Physicochemical Parameters and Antioxidant Activity in Beers with Dotted Hawthorn (Crataegus punctata)

Foods ◽

10.3390/foods9060775 ◽

2020 ◽

Vol 9 (6) ◽

pp. 775 ◽

Cited By ~ 2

Author(s):

Alan Gasiński ◽

Joanna Kawa-Rygielska ◽

Antoni Szumny ◽

Justyna Gąsior ◽

Adam Głowacki

Keyword(s):

Antioxidant Activity ◽

Volatile Compounds ◽

Solid Phase Microextraction ◽

High Performance ◽

Solid Phase ◽

Total Content ◽

Dpph Assay ◽

Frap Assay ◽

Abts Assay ◽

Hawthorn Fruit

Beer with the addition of dotted hawthorn (Crataegus punctata) fruit and juice was prepared and analysed. The content of carbohydrates, glycerol and ethanol in beers was determined by high-performance liquid chromatography (HPLC). Analysis of the total content of polyphenols was also performed using the Folin-Ciocalteu method, as well as determining antioxidant capacity by DPPH• and ABTS+• assay, and the ability to reduce iron ions by FRAP assay. Content of volatile compounds was analysed by means of solid-phase microextraction and gas chromatography coupled with mass spectroscopy. Beers with addition of hawthorn, both juice and fruit, had higher antioxidative potential and higher polyphenols concentration compared to control beer. The content of polyphenols in beers was in the range 200.5–410.0 mg GAE/L, and the antioxidant activity was in the range of 0.936–2.04 mmol TE/L (ABTS+• assay), 0.352–2.175 mmol TE/L (DPPH• assay) and 0.512–1.35 mmol TE/L (FRAP assay). A sensory evaluation of beers was also carried out. Beer with hawthorn fruit addition obtained the best scores in sensory analysis for criteria such as aroma, taste and overall quality. This beer had the highest content of volatile compounds (287.9 µg/100 mL of beer), while the control beer had lowest concentrations (35.9 µg/100 mL of beer).

Download Full-text

Simultaneous Detection and Validation of Analytical Markers of Swertia chirata by HPLC-DAD to Evaluate the Potency of Extracts and Fractions against Antioxidant Potential

Asian Journal of Chemistry ◽

10.14233/ajchem.2021.23085 ◽

2021 ◽

Vol 33 (5) ◽

pp. 977-982

Author(s):

Deepak Singh Janoti ◽

Kumud Upadhyaya

Keyword(s):

Ethyl Acetate ◽

Simultaneous Detection ◽

Water Extract ◽

Ethyl Acetate Fraction ◽

Antioxidant Potential ◽

Dpph Assay ◽

Frap Assay ◽

Hydroalcoholic Extract ◽

Abts Assay ◽

Swertia Chirata

The present study is based on the selection of extract and fraction of Swertia chirata plant for the antioxidant potential with HPLC fingerprinting, which includes the simultaneous detection and quantification of four analytical markers protocatechuic acid (PCA), swertiamarin (SM), mangiferin (MF) and amarogentin (AG) by HPLC-DAD. The yield of water extract (SWA), hydroalcoholic extract (SHA) and fractions of hydroalcoholic extracts were evaluated for their antioxidant potential against 2,2-diphenyl-1-picrylhydrazyl-hydrate free radical assay (DPPH assay), 2,2′-azino-bis(3- ethylbenzothiazoline-6-sulfonic acid radical scavenging assay (ABTS assay), total reducing assay (TRA), ferric reducing antioxidant potential assay (FRAP assay), total antioxidant capacity assay (TAC assay). The hydroalcoholic extracts (SHA) can be a better choice as compared to water extract (SWA) due to higher yield of extract (13.680 ± 0.548%) and higher antioxidant activity against DPPH assay, ABTS assay, TRA assay, FRAP assay and TAC assay. In hydroalcoholic extract (SHA), ethyl acetate fraction (SEA) showed most potent activity against DPPH (IC50 = 0.008 ± 0.002 mg/mL) and ABTS (0.025 ± 0.001 mg/mL). n-Hexane fraction of SHA showed higher FRAP (28.664 ± 3.153 μmol/mL) and TAC (3.263 ± 0.325 μmol/mL) value (equivalent to ascorbic acid in μmol/mL) but showed very low yield (0.468 ± 0.018%), SBU showed higher TRA value (0.413 ± 0.309 mg/mL). The ethyl acetate fraction (SEA) can be a choice for antioxidant as it showed second highest FRAP (19.547 ± 2.119 μmol/mL) and TAC (2.750 ± 0.466 μmol/mL) with better yield (2.473 ± 0.594%) as compared to n-hexane (SH) fractions (0.468 ± 0.018%).

Download Full-text

The interaction effect and optimal formulation of selected polyherbal extracts towards antioxidant activity

Food Research ◽

10.26656/fr.2017.4(6).281 ◽

2020 ◽

Vol 4 (6) ◽

pp. 2042-2048

Author(s):

N.F.A. Rahim ◽

N. Muhammad ◽

N. Abdullah ◽

B.A. Talip ◽

K.H. Poh

Keyword(s):

Interaction Effect ◽

Curcuma Longa ◽

Antioxidant Properties ◽

Radical Scavenging ◽

Total Phenolic ◽

Past Study ◽

Dpph Assay ◽

Frap Assay ◽

Antioxidant Power ◽

Curry Leaves

Past study showed that lemongrass (Cymbopogon citratus), curry leaves (Murrya koenigii), turmeric (Curcuma longa) and ginger (Zingiber officinale) contain phytochemicals associated with antioxidant properties. However, all the herbs are tested individually and rarely mix together. This study was conducted to examine the antioxidant properties and interaction effect when combined. The plants studied were decocted with distilled water. Eighteen formulations of aqueous extracts were established using simplex lattice mixture design that was generated by Design Expert software. The antioxidant properties were analyzed by 2-diphenyl-2-picryl hydrazyl radical scavenging (DPPH), ferric reducing antioxidant power (FRAP), total phenolic content (TPC) and total flavonoid content (TFC) assays. The result showed that the mixture of lemongrass and curry leaves extracts gave the highest reading in DPPH assay (91.14%), FRAP assay (215.66 mM) and TFC (22.62 µg Rutin/mL). In the DPPH assay, the ratio of one to one (1:1) mixture of lemongrass with other plants extracts showed antagonistic interaction. There were five (5) formulations that showed synergistic interaction in all assays. However, there were two (2) formulations that showed antagonistic interactions on both DPPH and FRAP assays. No additive effect was observed in all formulations. The suggested optimum formulation contains 53.7% lemongrass, 43.4% curry leaves, 2.9% ginger and 0.0% turmeric. Most of the mixtures presented synergistic interactions. This indicated the potential of plant extract mixtures to be developed into nutraceutical products in the future by conducting in-vivo study.

Download Full-text

Iron (FeII) Chelation, Ferric Reducing Antioxidant Power, and Immune Modulating Potential ofArisaema jacquemontii(Himalayan Cobra Lily)

BioMed Research International ◽

10.1155/2014/179865 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 21

Author(s):

Rasleen Sudan ◽

Madhulika Bhagat ◽

Sahil Gupta ◽

Jasvinder Singh ◽

Anupurna Koul

Keyword(s):

Methanol Extract ◽

Biological Activities ◽

Reducing Power ◽

Humoral Response ◽

Ferrous Ions ◽

Frap Assay ◽

Methanol Fraction ◽

Antioxidant Power ◽

Crude Methanol Extract

This study explored the antioxidant and immunomodulatory potential of ethnomedicinally valuable species, namely, Arisaema jacquemontiiof north-western Himalayan region. The tubers, leaves, and fruits of this plant were subjected to extraction using different solvents.In vitroantioxidant studies were performed in terms of chelation power on ferrous ions and FRAP assay. The crude methanol extract of leaves was found to harbour better chelating capacity (58% at 100 μg/mL) and reducing power (FRAP value1085.4±0.11 μMFe3+/g dry wt.) than all the other extracts. The crude methanol extract was thus further partitioned with solvents to yield five fractions. Antioxidant study of fractions suggested that the methanol fraction possessed significant chelation capacity (49.7% at 100 μg/mL) and reducing power with FRAP value of 1435.4 μM/g dry wt. The fractions were also studied for immune modulating potential where it was observed that hexane fraction had significant suppressive effect on mitogen induced T-cell and B-cell proliferation and remarkable stimulating effect on humoral response by 141% and on DTH response by 168% in immune suppressed mice as compared to the controls. Therefore, it can be concluded thatA. jacquemontiileaves hold considerable antioxidant and immunomodulating potential and they can be explored further for the identification of their chemical composition for a better understanding of their biological activities.

Download Full-text

Total Phenolic Content and Antioxidant Capacity of Selected Canned Fruits

Journal of Agricultural Science ◽

10.5539/jas.v9n13p96 ◽

2017 ◽

Vol 9 (13) ◽

pp. 96

Author(s):

Hanis Mastura Yahya ◽

Wendy Ann Roger ◽

Hasnah Haron

Keyword(s):

Antioxidant Capacity ◽

Food Processing ◽

Total Phenolic Content ◽

Phenolic Content ◽

Total Phenolic ◽

Dpph Assay ◽

Frap Assay ◽

Antioxidant Power ◽

Ferric Reducing Antioxidant Power

Fruits are high in polyphenols which are compounds associated with the protection against diseases such as diabetes and cancer. However, food processing including canning can leads to the loss of polyphenol in the fruits. Thus, the aim of this study was to evaluate the total phenolic content (TPC) and antioxidant capacity of canned fruits commercially available in the local supermarkets in Malaysia. The TPC was determined by using Folin-Ciocalteu method while the antioxidant capacity was evaluated by using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH assay) and Ferric Reducing Antioxidant Power (FRAP assay). Five types of different canned fruits with the total of 21 samples including longan, lychee, rambutan, pineapple and orange were selected for the analysis. The samples were analyzed in two forms which were, the homogenized (fruits and syrup) and syrup samples. Canned pineapples have the highest TPC for both homogenized (95.16±30.16 mg GAE/100 g) and syrup sample (108.62±33.88 mg GAE/100 g). For antioxidant capacity, canned pineapple also had the highest value for the homogenized sample (41.79±4.20 umol TE/100 g) while lychee was the highest (46.84±12.81 umol TE/100 g) for syrup sample assessed by DPPH assay. For FRAP assay, lychee was highest in antioxidant capacity for both homogenized sample (40.61±10.55 umol TE/100 g) and syrup sample (33.58±7.56 umol TE/100 g). A positive and significant (P < 0.001) correlation was found between TPC and antioxidant capacity (DPPH and FRAP). In conclusion, canned pineapple and lychee were the highest sources of polyphenol as compared to other types of canned fruits. Further investigation is warranted to determine the specific polyphenol present in the canned fruits.

Download Full-text

Comparative Analysis of In-Vitro Biological Activities of Methyl Eugenol Rich Cymbopogon khasianus Hack., Leaf Essential Oil with Pure Methyl Eugenol Compound

Current Pharmaceutical Biotechnology ◽

10.2174/1389201021666200217113921 ◽

2020 ◽

Vol 21 (10) ◽

pp. 927-938 ◽

Cited By ~ 7

Author(s):

Roktim Gogoi ◽

Rikraj Loying ◽

Neelav Sarma ◽

Twahira Begum ◽

Sudin K. Pandey ◽

...

Keyword(s):

Chemical Composition ◽

Essential Oil ◽

Biological Activities ◽

Methyl Eugenol ◽

Dpph Assay ◽

Pure Compound ◽

Allium Cepa Assay ◽

Anti Inflammatory ◽

Lemongrass Essential Oil

Background: The essential oil of methyl eugenol rich Cymbopogon khasianus Hack. was evaluated and its bioactivities were compared with pure methyl eugenol. So far, methyl eugenol rich essential oil of lemongrass was not studied for any biological activities; hence, the present study was conducted. Objective: This study examined the chemical composition of essential oil of methyl eugenol rich Cymbopogon khasianus Hack., and evaluated its antioxidant, anti-inflammatory, antimicrobial, and herbicidal properties and genotoxicity, which were compared with pure compound, methyl eugenol. Material and Methods: Methyl eugenol rich variety of Cymbopogon khasianus Hack., with registration no. INGR18037 (c.v. Jor Lab L-9) was collected from experimental farm CSIR-NEIST, Jorhat, Assam (26.7378°N, 94.1570°E). The essential oil wasobtained by hydro-distillation using a Clevenger apparatus. The chemical composition of the essential oil was evaluated using GC/MS analysis and its antioxidant (DPPH assay, reducing power assay), anti-inflammatory (Egg albumin denaturation assay), and antimicrobial (Disc diffusion assay, MIC) properties, seed germination effect and genotoxicity (Allium cepa assay) were studied and compared with pure Methyl Eugenol compound (ME). Results: Major components detected in the Essential Oil (EO) through Gas chromatography/mass spectroscopy analysis were methyl eugenol (73.17%) and β-myrcene (8.58%). A total of 35components were detected with a total identified area percentage of 98.34%. DPPH assay revealed considerable antioxidant activity of methyl eugenol rich lemongrass essential oil (IC50= 2.263 μg/mL), which is lower than standard ascorbic acid (IC50 2.58 μg/mL), and higher than standard Methyl Eugenol (ME) (IC50 2.253 μg/mL). Methyl eugenol rich lemongrass EO showed IC50 38.00 μg/mL, ME 36.44 μg/mL, and sodium diclofenac 22.76 μg/mL, in in-vitro anti-inflammatory test. Moderate antimicrobial activity towards the 8 tested microbes was shown by methyl eugenol rich lemongrass essential oil whose effectiveness against the microbes was less as compared to pure ME standard. Seed germination assay further revealed the herbicidal properties of methyl eugenol rich essential oil. Moreover, Allium cepa assay revealed moderate genotoxicity of the essential oil. Conclusion: This paper compared the antioxidant, anti-inflammatory, antimicrobial, genotoxicity and herbicidal activities of methyl eugenol rich lemongrass with pure methyl eugenol. This methyl eugenol rich lemongrass variety can be used as an alternative of methyl eugenol pure compound. Hence, the essential oil of this variety has the potential of developing cost-effective, easily available antioxidative/ antimicrobial drugs but its use should be under the safety range of methyl eugenol and needs further clinical trials.

Download Full-text

Majra Honey Abrogated the Normal and Cancer Cells Proliferation Inhibition by Juniperus procera Extract and Extract/Honey Generated AgNPs

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520620666200213104224 ◽

2020 ◽

Vol 20 (8) ◽

pp. 970-981

Author(s):

Hamed A. Ghramh ◽

Essam H. Ibrahim ◽

Mona Kilnay

Keyword(s):

Anticancer Activity ◽

Cancer Cells ◽

Biological Activities ◽

Sugar Content ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Bioactive Molecules ◽

Sds Page ◽

Splenic Cells ◽

Juniperus Procera

Background: Juniperus procera and Majra honey are well-known as a folk medicine in many countries. Objectives: This work aimed to study the immunomodulatory effects after mixing Majra honey, J. procera water leaves extract and silver Nanoparticles (AgNPs) on immune or cancer cells. Methods: Juniperus procera water leaves extract and 20% Majra honey were prepared. Both the extract and honey were used separately to synthesize AgNPs. AgNPs were characterized using UV/Vis spectrophotometry and electron microscopy. Bioactive molecules in honey and the extract were explored using Fourier Transform Infrared (FT-IR) spectroscopy. Protein profile of honey was explored using Sodium Dodecyl Sulfate- Polyacrylamide Gel Electrophoresis (SDS-PAGE) and honey sugar content was determined using High- Performance Liquid Chromatography (HPLC). Biological activities of honey and the extract were tested. Results: The results demonstrated the ability of the extract/honey to produce AgNPs in a spherical shape. The extract/honey contained many functional groups. SDS-PAGE of Majra honey showed many protein bands. HPLC revealed honey is of good quality and no external additives are added to it. The extract and extract+ AgNPs inhibited the growth of normal rat splenic cells while honey stimulated it. The extract+honey turned stimulatory to the splenic cells’ growth and significantly diminished the inhibitory potential of the extract containing AgNPs. Both the extract and honey have antimicrobial activities, this potential increased in the presence of AgNPs. Honey and Honey+AgNPs inhibited HepG2 cancer cell proliferation while Hela cell growth inhibited only with honey+AgNPs. Conclusion: Both honey and the extract have antibacterial and immunomodulatory potentials as well as the power to produce AgNPs. Majra honey alone showed anticancer activity against HepGe2 cells, but not against Hela cells, and when contained AgNPs had anticancer activity on both cell lines. Mixing of Majra honey with J. procera extract showed characterized immunomodulatory potentials that can be described as immunostimulant.

Download Full-text

Biological Activities of Carlina Oxide Isolated from the Roots of Carthamus caeruleus

The Natural Products Journal ◽

10.2174/2210315509666190117152740 ◽

2020 ◽

Vol 10 (2) ◽

pp. 145-152 ◽

Cited By ~ 1

Author(s):

Imane Rihab Mami ◽

Rania Belabbes ◽

Mohammed El Amine Dib ◽

Boufeldja Tabti ◽

Jean Costa ◽

...

Keyword(s):

Antifungal Activity ◽

Essential Oil ◽

Skin Diseases ◽

Antioxidant Activities ◽

Biological Activities ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Penicillium Expansum ◽

Natural Food ◽

Antioxidant Power

Background: Carthamus caeruleus belongs to the Asteraceae family. The roots are traditionally used as healing agents. They help to heal burns and treat skin diseases. They are also used against joint inflammation and are very effective against diseases such as irritable bowel syndrome for cancer patients. Objectives: The purpose of this work was i) to study the chemical composition of i) the essential oil and hydrosol extract of Carthamus caeruleus, ii) to isolate the major component of both extracts and iii) to evaluate their antioxidant, antifungal and insecticidal activities. Methods: The essential oil and hydrosol extract obtained from the roots were studied by GC and GC/MS. The antioxidant activities were performed using two different methods i) Radical scavenging activity (DPPH) and ii) the Ferric-Reducing Antioxidant Power (FRAP), using BHT as a positive control. Whereas, the antifungal activity of the essential oil and Carlina oxide was investigated against plant fungi. The fumigation toxicity of C. caeruleus essential oil besides Carlina oxide was evaluated against adults of Bactrocera oleae better known as the olive fly. Results: The essential oil and hydrosol extract were mainly represented by acetylenic compounds such as carline oxide and 13-methoxy carline oxide. Carlina oxide was isolated and identified by 1H and 13C NMR spectroscopic means. The results showed that Carlina oxide presented interesting antioxidant and antifungal properties, while C. caeruleus root essential oil had better insecticidal activity. Furthermore, Carlina oxide has demonstrated promising in vivo antifungal activity to control infection of apples by Penicillium expansum. Conclusion: Carlina oxide can be used as a natural food preservative and alternative to chemical fungicides to protect stored apple against Penicillium expansum.

Download Full-text

Changes in Amino Acid Profiles and Bioactive Compounds of Thai Silk Cocoons as Affected by Water Extraction

Molecules ◽

10.3390/molecules26072033 ◽

2021 ◽

Vol 26 (7) ◽

pp. 2033

Author(s):

Chuleeporn Bungthong ◽

Sirithon Siriamornpun

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Biological Activities ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Silk Protein ◽

Extraction Time ◽

Antioxidant Power ◽

Silk Cocoon ◽

Amino Acid Profiles

Silk proteins have many advantageous components including proteins and pigments. The proteins—sericin and fibroin—have been widely studied for medical applications due to their good physiochemical properties and biological activities. Various strains of cocoon display different compositions such as amino-acid profiles and levels of antioxidant activity. Therefore, the objectives of this study were to find a suitable silk protein extraction method to obtain products with chemical and biological properties suitable as functional foods in two strains of Bombyx mori silk cocoon (Nangsew strains; yellow cocoon) and Samia ricini silk cocoon (Eri strains; white cocoon) extracted by water at 100 °C for 2, 4, 6 and 8 h. The results showed that Nangsew strains extracted for 6 h contained the highest amounts of protein, amino acids, total phenolics (TPC) and total flavonoids (TFC), plus DPPH radical-scavenging activity, ABTS radical scavenging capacity, and ferric reducing antioxidant power (FRAP), anti-glycation, α-amylase and α-glucosidase inhibition. The longer extraction time produced higher concentrations of amino acids, contributing to sweet and umami tastes in both silk strains. It seemed that the bitterness decreased as the extraction time increased, resulting in improvements in the sweetness and umami of silk-protein extracts.

Download Full-text