This research was supported by CARS-tea and the Innovation Project for the Chinese Academy of Agricultural Sciences (CAAS-ASTIP-TRI).

1. Production of matcha-embedded suspension
<ol>
	<li>Place 4 g of carboxymethyl chitosan (see Table of Materials) in 100 mL of distilled water to prepare a 0.04 g/mL of carboxymethyl chitosan stock solution. To dissolve carboxymethyl chitosan heat to 60 &#176;C on constant temperature heating magnetic stirrer.</li>
	<li>Dissolve 4 g of whey protein (see Table of Materials) in 50 mL of distilled water to prepare a 0.08 g/mL of whey protein stock solution.</li>
	<li>After the solutions cool, store them in a freezer and refrigerate them overnight to fully saturate the polymer molecule.</li>
	<li>Place 8 g of matcha and 4 g NaCl (see Table of Materials) in a beaker and add 50 mL of sterile boiled water to prepare matcha slurry. Assist the dissolution process using a glass stirring rod. Sterile water is deionized water that has been boiled in a pot for 15 min.</li>
	<li>Mix matcha slurry with 50 mL of carboxymethyl chitosan solution and blend with a magnetic stirring apparatus at 300 rpm at room temperature.</li>
	<li>Drip 25 mL of whey protein into the mixture and stir at 300 rpm for 30 min to create an embedded suspension. (see Figure 1). The suspension should be prepared concurrently with the noodle production and stored at a temperature of 4 &#176;C on the same day. 
	NOTE: The pH of the matcha-embedded suspension solution was left unadjusted, thus solely influenced by the matcha or wall material.</li>
</ol>
2. Microwave treatment of wheat flour
<ol>
	<li>Distribute 300 g of wheat flour in a round plastic container. Cover the container with plastic wrap and place it in the microwave oven at 700 W for 60 s. Afterward, keep the container with flour outside until it feels cool.</li>
</ol>
3. Production of matcha noodles
<ol>
	<li>Dough mixing: Pour 125 mL of pre-formed matcha-embedded suspension and 15 mL of water into 300 g of microwave-treated wheat flour slowly. Gently pull the flour into the center, bit by bit, until the embedded suspension is incorporated.
	<ol>
		<li>For non-microwave-treated wheat flour, use 125 mL of water instead of matcha-embedded suspension to prepare noodles, which are labeled as blank noodles (control). Add 125 mL of water and 8 g of matcha to non-microwave-treated wheat flour to prepare noodles and designate these as matcha noodles (M-noodles).</li>
	</ol>
	</li>
	<li>Kneading the dough: Knead the noodle dough with a dough mixer for 7 min. The dough should be smooth and pliable, not wet or sticky when done.</li>
	<li>Resting: Return the ball of dough to its mixing bowl and cover it with a damp tea towel. Let it rest for 30 min at room temperature.</li>
	<li>Prepare noodles as described below.
	<ol>
		<li>Divide the dough into 4 equal pieces, then rewrap 3 and set aside. Lightly flour the unwrapped piece, lifting it occasionally to ensure that it does not stick.</li>
		<li>Adjust the press roller spacing of the dough press to 3.5 mm. Place the dough on a dough press to sheet, and then compound. Press the dough sheet repeatedly until it reaches a smooth and pliable consistency.</li>
		<li>Thin the dough sheet to 1 mm. Starting from 3.5 mm, adjust the press roller spacing to 2 mm and then 1 mm. Press the sheet 3x in each roller spacing.</li>
		<li>Cover loosely with clingfilm, and then repeat steps 3.4.1-3.4.3 with the remaining dough. 
		NOTE: In order to ensure that the pressing process of each batch of samples is consistent, the press roll spacing is adjusted once, and the next spacing is adjusted after each sample is passed.</li>
		<li>Slit the noodle strands into 22 cm long, 1 mm thick, and 3.0 mm wide samples (see Figure 2). Dust about 3.75 g semolina to make sure noodles do not stick together.</li>
	</ol>
	</li>
</ol>
4. Sensory evaluation and physical property analysis
<ol>
	<li>Sensory evaluation
	<ol>
		<li>Place 30 g of noodles in 600 mL of boiling water and cook for 5 min. Immerse cooked noodles in cold water immediately, before testing.</li>
		<li>Perform sensory evaluation of noodle samples using quantitative descriptive analysis (QDA) as outlined in Li et al.12. Ensure that the sensory characteristics of the samples are evaluated by 12 trained panelists using a nine-point hedonic scale with 9 denoting like extremely and 1 denoting dislike extremely.</li>
	</ol>
	</li>
	<li>Color measurement
	<ol>
		<li>Cut cooked as well as fresh samples into pieces of about 10 cm and place them under the instrumental aperture of the colorimeter.</li>
		<li>Press the instrumental button to measure the color of the fresh noodles and repeat the test 6x for each sample.</li>
	</ol>
	</li>
	<li>Texture analyzer
	<ol>
		<li>Determine the texture property of cooked as well as fresh noodles using a texture analyzer and calculate based on texture profile analysis (TPA).</li>
		<li>Place five strands of noodles on the test bench and repeat the test 6x for each sample.</li>
	</ol>
	</li>
</ol>
5. Data analysis
<ol>
	<li>Analyze the data by variance analysis (ANOVA) and consider the difference significant when p &#60; 0.05.</li>
</ol>

Advancements in Production of Color-Stable Matcha Fresh Noodles

<ol>
	<li>Yu, K., Zhou, H. M., Zhu, K. X., Guo, X. N., Peng, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increasing+the+physicochemical+stability+of+stored+green+tea+noodles:+Analysis+of+the+quality+and+chemical+components.">Increasing the physicochemical stability of stored green tea noodles: Analysis of the quality and chemical components.</a> Food Chem. 278, 333-341 (2019).</li><li>Nguyen, T. T. L., Gilbert, R. G., Gidley, M. J., Fox, G. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+contribution+of+&#946;-glucan+and+starch+fine+structure+to+texture+of+oat-fortified+wheat+noodles.">The contribution of &#946;-glucan and starch fine structure to texture of oat-fortified wheat noodles.</a> Food Chem. 372, 131291 (2022).</li><li>Baskaran, D., Muthupandian, K., Gnanalakshmi, K. S., Pugazenthi, T. R., Ayyadurai, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physical+properties+of+noodles+enriched+with+whey+protein+concentrate+(wpc)+and+skim+milk+powder+(smp).">Physical properties of noodles enriched with whey protein concentrate (wpc) and skim milk powder (smp).</a> J Stored Prod Postharvest Res. 2 (6), 127-130 (2011).</li><li>Chen, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+starch+noodles+made+from+three+typical+Chinese+sweet-potato+starches.">Evaluation of starch noodles made from three typical Chinese sweet-potato starches.</a> J Food Sci. 67 (9), 3342-3347 (2002).</li><li>Reshmi, S. K., Sudha, M. L., Shashirekha, M. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Noodles+fortified+with+citrus+maxima+(pomelo)+fruit+segments+suiting+the+diabetic+population.">Noodles fortified with citrus maxima (pomelo) fruit segments suiting the diabetic population.</a> Bioactive Carb Dietary Fibre. 22, 100213 (2020).</li><li>Phuah, Y. Q., Chang, S. K., Ng, W. J., Lam, M. Q., Ee, K. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+on+matcha:+Chemical+composition,+health+benefits,+with+insights+on+its+quality+control+by+applying+chemometrics+and+multi-omics.">A review on matcha: Chemical composition, health benefits, with insights on its quality control by applying chemometrics and multi-omics.</a> Food Res Int. 170, 113007 (2023).</li><li>Hou, G. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Asian noodles: science, technology, and processing. , (2010).</li><li>Asenstorfer, R. E., Appelbee, M. J., Mares, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+protein+on+darkening+in+yellow+alkaline+noodles.">Impact of protein on darkening in yellow alkaline noodles.</a> J Agri Food Chem. 58 (7), 4500-4507 (2010).</li><li>Asenstorfer, R. E., Appelbee, M. J., Kusznir, C. A., Mares, D. 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H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+characterization+of+whey+protein+isolate-chlorophyll+microcapsules+by+spray+drying:+Effect+of+WPI+ratios+on+the+physicochemical+and+antioxidant+properties.">Preparation and characterization of whey protein isolate-chlorophyll microcapsules by spray drying: Effect of WPI ratios on the physicochemical and antioxidant properties.</a> J Food Eng. 267, 109729 (2020).</li><li>Ramdha, T., Ching, S. H., Prakash, S., Bhandari, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+alginate-biopolymers+(protein,+hydrocolloid,+starch)+composite+microgels+prepared+by+the+spray+aerosol+technique+as+a+carrier+for+green+tea+polyphenols.">Evaluation of alginate-biopolymers (protein, hydrocolloid, starch) composite microgels prepared by the spray aerosol technique as a carrier for green tea polyphenols.</a> Food Chem. 3371, 1131382 (2022).</li><li>Pasrija, D., Ezhilarasi, P. N., Indrani, D., Anandharamakrishnan, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microencapsulation+of+green+tea+polyphenols+and+its+effect+on+incorporated+bread+quality.">Microencapsulation of green tea polyphenols and its effect on incorporated bread quality.</a> LWT - Food Sci Tech. 64, 289-296 (2015).</li><li>Li, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+superfine+green+tea+powder+on+the+thermodynamic,+rheological+and+fresh+noodle+making+properties+of+wheat+flour.">Effect of superfine green tea powder on the thermodynamic, rheological and fresh noodle making properties of wheat flour.</a> LWT - Food Sci Techn. 46 (1), 23-28 (2012).</li><li>Kun Yu, K., Zhou, H. M., Zhu, K. X., Guo, X. N., Peng, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physicochemical+changes+in+the+discoloration+of+dried+green+tea+noodles+caused+by+polyphenol+oxidase+from+wheat+flour.">Physicochemical changes in the discoloration of dried green tea noodles caused by polyphenol oxidase from wheat flour.</a> LWT - Food Sci Tech. 130, 109614 (2020).</li><li>Doxastakis, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Technological+properties+and+non-enzymatic+browning+of+white+lupin+protein+enriched+spaghetti.">Technological properties and non-enzymatic browning of white lupin protein enriched spaghetti.</a> Food Chemistry. 101 (1), 57-64 (2007).</li><li>Xu, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+heat+treatment+on+polyphenol+oxidase+activity+and+textural+properties+of+jackfruit+bulb.">Effects of heat treatment on polyphenol oxidase activity and textural properties of jackfruit bulb.</a> J Food Process Preserv. 40 (5), 943-949 (2016).</li><li>Yadav, D. N., Patki, P. E., Sharma, G. K., Bawa, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+microwave+heating+of+wheat+grains+on+the+browning+of+dough+and+quality+of+chapattis.">Effect of microwave heating of wheat grains on the browning of dough and quality of chapattis.</a> Int J Food Sci Tech. 43 (7), 1217-1225 (2008).</li><li>Xue, C. 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The authors have nothing to disclose.

Compared to instant noodles, fine-dried noodles, and other similar products, fresh noodles have a greater capacity to preserve their original taste and flavor, making them highly promising in the market. A previous study has shown that green tea could enhance the overall quality of fresh noodles to a certain degree16. Therefore, incorporating tea into the flour product system of fresh noodles aims to prioritize both high quality and health benefits, in line with the contemporary trend of promoting...

Noodles are a staple of traditional grain-based cuisine in China, with approximately 40% of the wheat production in Asian countries being utilized for noodle processing1. Nevertheless, the basic nutritional component of wheat flour is insufficient to satisfy the increasing nutritional needs of consumers. Therefore, several investigators have opted to replace a portion of the wheat flour in noodles with alternative natural ingredients, such as oat bran2, milk protein3, sweet potato4, and citrus maxima5, in order to enhance the nutritional and functional qualities of the noodles. Matcha is an abundant bioactive compound possessing antioxidant and anti-inflammatory properties, which have the potential to mitigate the risk of cardiovascular disease and prevent chronic illnesses6. Consequently, there has been a burgeoning interest in investigating the integration of matcha into traditional culinary fare, including Chinese steamed bread, rice cake, and particularly fresh noodles.
However, fresh noodles are prone to time-dependent darkening, leading to unfavorable changes in the visual appearance of the product, which poses a significant challenge to the storage of fresh noodles7. It is widely agreed that the discoloration observed during the storage of fresh noodles is mainly caused by the presence of polyphenol oxidase (PPO)7,8. Additionally, it was indicated that the soluble protein fraction is involved in the process of non-polyphenol oxidase (non-PPO) darkening9. Extensive efforts have been devoted in recent years to mitigate the darkening of PPO during storage. Previous studies have suggested that acid inhibitors and heat treatment applied to raw noodles could effectively achieve this objective by denaturing proteins and consequently inhibiting enzyme activity10,11. Chlorophyll is susceptible to changes in pH, temperature, and heat, and the vibrant green hue of green tea noodles is primarily attributed to chlorophyll10. It is evident that there are limitations in effectively controlling the color of green tea noodles through the direct addition of acid inhibitors and heat treatment.
In addition to the thermal processing of wheat flour, the preservation of chlorophyll in matcha noodles is a critical factor to consider. Several methods have been proposed to prolong the storage time of chlorophyll and preserve its pigment, including the use of alkalinizing agents, copper complexations, and low-temperature storage12. Unfortunately, the majority of processes necessitate a pH level close to nature in order to reduce the occurrence of unfavorable chemical reactions. The stability concern may be potentially mitigated by the copper complex of chlorophyll derivatives, which exhibit a green color reminiscent of natural chlorophyll. However, individuals exhibit a preference for natural chlorophyll over artificial colors. Microencapsulation techniques have emerged as a viable solution to the challenge of improving bioactive compounds&#39; stability by providing barriers against environmental conditions such as oxygen, pH, ionic strength, and temperature13,14,15. Until now, tea extract, catechins, and chlorophyll have been continuously studied for their stability and controlled release properties when embedded in different wall materials14. However, the incorporation of microcapsules into noodles has not yet been proposed15.
In this study, we described a method that embeds matcha with whey protein and carboxymethyl chitosan and microwave-treating wheat flour to obtain color-stable matcha fresh noodles. The addition of microencapsulated bioactive compounds to food facilitates the creation of novel functional food products while preserving the inherent qualitative attributes. We present the results obtained using this processing protocol to investigate alterations in color values of matcha noodles following storage. The specific objective of the study was to determine the optimal approach for preparing matcha noodles that demonstrate both exceptional color and flavor.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Carboxymethyl chitosan</td>
			<td>Mackin</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Colorimeter</td>
			<td>3nh</td>
			<td>NH-300+</td>
			<td></td>
		</tr>
		<tr>
			<td>Dough mixer</td>
			<td>ACA</td>
			<td>AM-CG108</td>
			<td></td>
		</tr>
		<tr>
			<td>Freezer</td>
			<td>Haier</td>
			<td>BCD-252KS</td>
			<td></td>
		</tr>
		<tr>
			<td>Heating magnetic stirrer</td>
			<td>Yuhua</td>
			<td>DF-101S</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnetic stirrer</td>
			<td>Keezo</td>
			<td>KMS-521D</td>
			<td></td>
		</tr>
		<tr>
			<td>Matcha</td>
			<td>Jinhua Feicui</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Microwave</td>
			<td>Panasonic</td>
			<td>NN-GF351X</td>
			<td></td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>China National Salt Industry Corporation</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Noodle maker</td>
			<td>Tianxi</td>
			<td>JCD-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Texture analyzer</td>
			<td>Lotun Science</td>
			<td>TA-XT plus</td>
			<td></td>
		</tr>
		<tr>
			<td>Wheat flour</td>
			<td>Queen</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Whey protein</td>
			<td>Yuanye</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

preparation of matcha fresh noodles with stable color using embedding method and microwave treatment

Matcha, as a healthy food additive, has been widely utilized in traditional foods such as noodles, cookies, and bread. However, there are several challenges that must be addressed in the quality of matcha-incorporated foods, with the most significant being the prevention of matcha discoloration. In this study, we introduce a novel approach involving the incorporation of matcha with whey protein (0.08&#160;g/mL) and carboxymethyl chitosan (0.04&#160;g/mL), accompanied by microwave treatment at 700 W for 60 s of wheat flour to produce color-stable matcha fresh noodles. All steps involved in the production process of matcha fresh noodles are presented in the article, including matcha embedding treatment, microwave treatment of wheat flour, kneading the dough, leaving to prove, dividing the dough, rolling out the dough and slicing the sheets by noodle press. The findings revealed a 72.13% reduction in discoloration of fresh matcha noodles following embedding and microwave treatment, compared to untreated fresh matcha noodles. Moreover, the combined process did not have any detrimental impact on the sensory attributes of matcha noodles, including their aroma and taste. Therefore, the novel method proposed in this study holds significant potential for enhancing the color stability of fresh matcha noodles during preparation.

This protocol allowed for the sensory and physical property analysis of processed matcha-incorporated foods and noodles, beginning with matcha treatment and continuing through the intermediate stages of processing to the final product. This protocol was coupled with embedding and microwave to produce matcha noodles (Figure 3). The fresh noodles with unencapsulated matcha, with embedded matcha and microwave treatment, and without any matcha were marked as M-Noodles, ME-Noodle...

Author Spotlight: Enhancing Flavor Interaction of Food Using Matcha Microcapsules 

The protocol describes a method for embedding matcha with whey protein and carboxymethyl chitosan and microwave-treating wheat flour to obtain color-stable matcha fresh noodles.

Preparation of Matcha Fresh Noodles with Stable Color using Embedding Method and Microwave Treatment

Matcha, as a healthy food additive, has been widely utilized in traditional foods such as noodles, cookies, and bread. However, there are several ...

preparation-matcha-fresh-noodles-with-stable-color-using-embedding

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541 Views.  Tea Research Institute Chinese Academy of Agricultural Sciences. The protocol describes a method for embedding matcha with whey protein and carboxymethyl chitosan and microwave-treating wheat flour to obtain color-stable matcha fresh noodles. 

Video: Author Spotlight: Enhancing Flavor Interaction of Food Using Matcha Microcapsules 

Preparation of Silica Nanoparticles Through Microwave-assisted Acid-catalysis

Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle diameters ranging from 30-250 nm by varying the reaction conditions. Through the selection of a microwave compatible solvent, silicic acid precursor, catalyst, and microwave irradiation time, these microwave-assisted methods were capable of overcoming the previously reported shortcomings associated with synthesis of silica nanoparticles using microwave reactors. The siloxane precursor was hydrolyzed using the acid catalyst, HCl. Acetone, a low-tan &#948; solvent, mediates the condensation reactions and has minimal interaction with the electromagnetic field. Condensation reactions begin when the silicic acid precursor couples with the microwave radiation, leading to silica nanoparticle sol formation. The silica nanoparticles were characterized by dynamic light scattering data and scanning electron microscopy, which show the materials&#39; morphology and size to be dependent on the reaction conditions. Microwave-assisted reactions produce silica nanoparticles with roughened textured surfaces that are atypical for silica sols produced by St&#246;ber&#39;s methods, which have smooth surfaces.

Silica nanoparticles were prepared using acid-catalysis of a siloxane precursor and microwave-assisted synthetic techniques resulting in the controlled growth of nanomaterials ranging from 30-250 nm in diameter. The growth dynamics can be controlled by varying the initial silicic acid concentration, time of the reaction, and temperature of reaction.

Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle ...

Quantitative Proteomics Using Reductive Dimethylation for Stable Isotope Labeling

Stable isotope labeling of peptides by reductive dimethylation (ReDi labeling) is a method to accurately quantify protein expression differences between samples using mass spectrometry. ReDi labeling is performed using either regular (light) or deuterated (heavy) forms of formaldehyde and sodium cyanoborohydride to add two methyl groups to each free amine. Here we demonstrate a robust protocol for ReDi labeling and quantitative comparison of complex protein mixtures. Protein samples for comparison are digested into peptides, labeled to carry either light or heavy methyl tags, mixed, and co-analyzed by LC-MS/MS. Relative protein abundances are quantified by comparing the ion chromatogram peak areas of heavy and light labeled versions of the constituent peptide extracted from the full MS spectra. The method described here includes sample preparation by reversed-phase solid phase extraction, on-column ReDi labeling of peptides, peptide fractionation by basic pH reversed-phase (BPRP) chromatography, and StageTip peptide purification. We discuss advantages and limitations of ReDi labeling with respect to other methods for stable isotope incorporation. We highlight novel applications using ReDi labeling as a fast, inexpensive, and accurate method to compare protein abundances in nearly any type of sample.

Stable isotope labeling of peptides by reductive dimethylation (ReDi labeling) is a rapid, inexpensive strategy for accurate mass spectrometry-based quantitative proteomics. Here we demonstrate a robust method for preparation and analysis of protein mixtures using the ReDi approach that can be applied to nearly any sample type.

Stable isotope labeling of peptides by reductive dimethylation (ReDi labeling) is a method to accurately quantify protein expression differences between ...

A Simple Method for the Size Controlled Synthesis of Stable Oligomeric Clusters of Gold Nanoparticles under Ambient Conditions

Reducing dilute aqueous HAuCl4 with sodium thiocyanate (NaSCN) under alkaline conditions produces 2 to 3 nm diameter nanoparticles. Stable grape-like oligomeric clusters of these yellow nanoparticles of narrow size distribution are synthesized under ambient conditions via two methods. The delay-time method controls the number of subunits in the oligoclusters by varying the time between the addition of HAuCl4 to alkaline solution and the subsequent addition of reducing agent, NaSCN. The yellow oligoclusters produced range in size from ~3 to ~25 nm. This size range can be further extended by an add-on method utilizing hydroxylated gold chloride (Na+[Au(OH4-x)Clx]-) to auto-catalytically increase the number of subunits in the as-synthesized oligocluster nanoparticles, providing a total range of 3 nm to 70 nm. The crude oligocluster preparations display narrow size distributions and do not require further fractionation for most purposes. The oligoclusters formed can be concentrated &#62;300 fold without aggregation and the crude reaction mixtures remain stable for weeks without further processing. Because these oligomeric clusters can be concentrated before derivatization they allow expensive derivatizing agents to be used economically. In addition, we present two models by which predictions of particle size can be made with great accuracy.

We describe a simple method for producing highly stable oligomeric clusters of gold nanoparticles via the reduction of chloroauric acid (HAuCl4) with sodium thiocyanate (NaSCN). The oligoclusters have a narrow size distribution and can be produced with a wide range of sizes and surface coats.

Reducing dilute aqueous HAuCl4 with sodium thiocyanate (NaSCN) under alkaline conditions produces 2 to 3 nm diameter nanoparticles. Stable grape-like ...

Development of a Backbone Cyclic Peptide Library as Potential Antiparasitic Therapeutics Using Microwave Irradiation

Protein-protein interactions (PPIs) are intimately involved in almost all biological processes and are linked to many human diseases. Therefore, there is a major effort to target PPIs in basic research and in the pharmaceutical industry. Protein-protein interfaces are usually large, flat, and often lack pockets, complicating the discovery of small molecules that target such sites. Alternative targeting approaches using antibodies have limitations due to poor oral bioavailability, low cell-permeability, and production inefficiency.
Using peptides to target PPI interfaces has several advantages. Peptides have higher conformational flexibility, increased selectivity, and are generally inexpensive. However, peptides have their own limitations including poor stability and inefficiency crossing cell membranes. To overcome such limitations, peptide cyclization can be performed. Cyclization has been demonstrated to improve peptide selectivity, metabolic stability, and bioavailability. However, predicting the bioactive conformation of a cyclic peptide is not trivial. To overcome this challenge, one attractive approach it to screen a focused library to screen in which all backbone cyclic peptides have the same primary sequence, but differ in parameters that influence their conformation, such as ring size and position.
We describe a detailed protocol for synthesizing a library of backbone cyclic peptides targeting specific parasite PPIs. Using a rational design approach, we developed peptides derived from the scaffold protein Leishmania receptor for activated C-kinase (LACK). We hypothesized that sequences in LACK that are conserved in parasites, but not in the mammalian host homolog, may represent interaction sites for proteins that are critical for the parasites&#39; viability. The cyclic peptides were synthesized using microwave irradiation to reduce reaction times and increase efficiency. Developing a library of backbone cyclic peptides with different ring sizes facilitates a systematic screen for the most biological active conformation. This method provides a general, fast, and facile way to synthesize cyclic peptides.

A simple and general method for the synthesis of cyclic peptides using microwave irradiation is outlined. This procedure enables the synthesis of backbone cyclic peptides with a collection of different conformations while retaining the side chains and the pharmacophoric moieties., and therefore, allows to screen for the bioactive conformation.

Protein-protein interactions (PPIs) are intimately involved in almost all biological processes and are linked to many human diseases. Therefore, there is ...

Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of Phosphorus(I)

We present herein the optimized synthesis of a triphosphenium bromide salt. Apart from being a versatile metathesis reagent, this unusually stable low-valent-phosphorus-containing compound acts as a useful P+ transfer agent. Unlike traditional methods employed to access low-coordinate phosphorus species which usually require pyrophoric phosphorus-containing precursors (white phosphorus, Tris(trimethylsilyl)phosphine, etc.), or harsh reducing agents (alkali metals, potassium graphite, etc.), the current approach does not involve pyrophoric or explosive reagents and can be done on large scales (&#62;20 g) in excellent yields by undergraduates with basic air-free synthetic training. The bromide counter ion is readily exchanged with other anions such as tetraphenyl borate (described herein) using typical salt metathesis reagents to obtain materials with desired properties and reactivities. The versatility of this P+ transfer approach is exemplified by the reactions of these triphosphenium precursors with an N-heterocyclic carbene and an anionic bisphosphine, each of which readily displace the neutral bisphosphine to give an NHC-stabilized phosphorus(I) cation and a phosphorus(I) containing zwitterion, respectively.

Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of PhosphorusI

The synthesis of a triphosphenium bromide salt is described and its use as a P+ transfer agent is outlined by reactions with an N-heterocyclic carbene and an anionic bisphosphine, yielding an NHC-stabilized P(I) cation and a P(I) containing zwitterion, respectively.

We present herein the optimized synthesis of a triphosphenium bromide salt. Apart from being a versatile metathesis reagent, this unusually stable ...

Green and Low-cost Production of Thermally Stable and Carboxylated Cellulose Nanocrystals and Nanofibrils Using Highly Recyclable Dicarboxylic Acids

Here we demonstrate potentially low cost and green productions of high thermally stable and carboxylated cellulose nanocrystals (CNCs) and nanofibrils (CNF) from bleached eucalyptus pulp (BEP) and unbleached mixed hardwood kraft pulp (UMHP) fibers using highly recyclable dicarboxylic solid acids. Typical operating conditions were acid concentrations of 50 - 70 wt% at 100 &#176;C for 60 min and 120 &#176;C (no boiling at atmospheric pressure) for 120 min, for BEP and UMHP, respectively. The resultant CNCs have a higher thermal degradation temperature than their corresponding feed fibers and carboxylic acid group content from 0.2 - 0.4 mmol/g. The low strength (high pKa of 1.0 - 3.0) of organic acids also resulted in CNCs with both longer lengths of approximately 239 - 336 nm and higher crystallinity than CNCs produced using mineral acids. Cellulose loss to sugar was minimal. Fibrous cellulosic solid residue (FCSR) from the dicarboxylic acid hydrolysis was used to produce carboxylated CNFs through subsequent mechanical fibrillation with low energy input.

Here we demonstrate a novel method for green and sustainable productions of highly thermally stable and carboxylated cellulose nanocrystals (CNC) and nanofibrils (CNF) using highly recyclable solid dicarboxylic acids.

Here we demonstrate potentially low cost and green productions of high thermally stable and carboxylated cellulose nanocrystals (CNCs) and nanofibrils ...

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles

Bicyclic aziridinium ions were generated by the removal of an appropriate leaving group through internal nucleophilic attack by nitrogen atom in the aziridine ring. The utility of bicyclic aziridinium ions, specifically 1-azoniabicyclo[3.1.0]hexane and 1-azoniabicyclo[4.1.0]heptane tosylate highlighted in the aziridine ring openings by the nucleophile with the release of the ring strain to yield the corresponding ring-expanded azaheterocycles such as pyrrolidine, piperidine and azepane with diverse substituents on the ring in regio- and stereospecific manner. Herein, we report a simple and convenient method for the preparation of the stable 1-azabicyclo[4.1.0]heptane tosylate followed by selective ring opening via a nucleophilic attack either at the bridge or at the bridgehead carbon to yield piperidine and azepane rings, respectively. This synthetic strategy allowed us to prepare biologically active natural products containing piperidine and azepane motif including sedamine, allosedamine, fagomine and balanol in highly efficient manner.

Bicyclic aziridinium ions such as 1-azoniabicyclo[4.1.0]heptane tosylate were generated from 2-[4-tolenesulfonyloxybutyl]aziridine, which was utilized for the preparation of substituted piperidines and azepanes via regio- and stereospecific ring-expansion with various nucleophiles. This highly efficient protocol allowed us to prepare diverse azaheterocycles including natural products such as fagomine, febrifugine analogue and balanol.

Bicyclic aziridinium ions were generated by the removal of an appropriate leaving group through internal nucleophilic attack by nitrogen atom in the ...

Preparation of Functional Silica Using a Bioinspired Method

The goal of the protocols described herein is to synthesize bioinspired silica materials, perform enzyme encapsulation therein, and partially or totally purify the same by acid elution. By combining sodium silicate with a polyfunctional bioinspired additive, silica is rapidly formed at ambient conditions upon neutralization. 
The effect of neutralization rate and biomolecule addition point on silica yield are investigated, and biomolecule immobilization efficiency is reported for varying addition point. In contrast to other porous silica synthesis methods, it is shown that the mild conditions required for bioinspired silica synthesis are fully compatible with the encapsulation of delicate biomolecules. Additionally, mild conditions are used across all synthesis and modification steps, making bioinspired silica a promising target for the scale-up and commercialization as both a bare material and active support medium.
The synthesis is shown to be highly sensitive to conditions, i.e., the neutralization rate and final synthesis pH, however tight control over these parameters is demonstrated through the use of auto titration methods, leading to high reproducibility in reaction progression pathway and yield. 
Therefore, bioinspired silica is an excellent active material support choice, showing versatility towards many current applications, not limited to those demonstrated here, and potency in future applications.

Here, we present a protocol to synthesize bioinspired silica materials and immobilize enzymes therein. Silica is synthesized by combining sodium silicate and an amine &#39;additive&#39;, which neutralize at a controlled rate. Material properties and function can be altered either by in situ enzyme immobilization or post-synthetic acid elution of encapsulated additives.

The goal of the protocols described herein is to synthesize bioinspired silica materials, perform enzyme encapsulation therein, and partially or totally ...

Microwave-Assisted Preparation of 1-Aryl-1H-pyrazole-5-amines

A synthetic process for the preparation of a variety of 1-aryl-1H-pyrazole-5-amines was developed. The microwave-mediated nature of this method makes it efficient in both time and resources and utilizes water as the solvent. 3-Aminocrotononitrile or an appropriate &#945;-cyanoketone is combined with an aryl hydrazine and dissolved in 1 M HCl. The mixture is then heated in a microwave reactor at 150 &#176;C, typically for 10-15 min. The product can be readily obtained by basifying the solution with 10% NaOH and isolating the desired compound with a simple vacuum filtration. The use of water as a solvent in this reaction lends to its ease and utility in production, and this method is easily reproducible with a variety of functional groups. Typical isolated yields range from 70-90%, and reactions can be performed on the milligram to gram scale with little to no change in observed yields. Some of the applications of these molecules and their derivatives include pesticides, anti-malarials, and chemotherapeutics, among many others.

Microwave-Assisted Preparation of 1-Aryl-1H-pyrazole-5-amines

1-Aryl-1H-pyrazole-5-amines are prepared from aryl hydrazines combined with either 3-aminocrotononitrile or an &#945;-cyanoketone in a 1 M HCl solution using a microwave reactor. Most reactions are done in 10-15 minutes and pure product can be obtained via vacuum filtration with typical isolated yields of 70-90%.

A synthetic process for the preparation of a variety of 1-aryl-1H-pyrazole-5-amines was developed. The microwave-mediated nature of this method makes it ...

A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis

Heteroarylation introduces heteroaryl fragments to organic molecules. Despite the numerous available reactions reported for arylation via transition metal catalysis, the literature on direct heteroarylation is scarce. The presence of heteroatoms such as nitrogen, sulfur and oxygen often make heteroarylation a challenging research field due to catalyst poisoning, product decomposition and the rest. This protocol details a highly efficient direct &#945;-C(sp3) heteroarylation of ketones under microwave irradiation. Key factors for successful heteroarylation include the use of XPhos Palladacycle Gen. 4 Catalyst, excess base to suppress side reactions and the high temperature and pressure achieved in a sealed reaction vial under microwave irradiation. The heteroarylation compounds prepared by this method were fully characterized by proton nuclear magnetic resonance spectroscopy (1H NMR), carbon nuclear magnetic resonance spectroscopy (13C NMR) and high-resolution mass spectrometry (HRMS). This methodology has several advantages over literature precedents including broad substrate scope, rapid reaction time, greener procedure and operational simplicity by eliminating the preparation of intermediates such as silyl enol ether. Possible applications for this protocol include, but are not limited to, diversity-oriented synthesis for the discovery of biologically active small molecules, domino synthesis for the preparation of natural products and ligand development for new transition metal catalytic systems.

Heteroaryl compounds are important molecules utilized in organic synthesis, medicinal and biological chemistry. A microwave-assisted heteroarylation using palladium catalysis provides a rapid and efficient method to attach heteroaryl moieties directly to ketone substrates.

Heteroarylation introduces heteroaryl fragments to organic molecules. Despite the numerous available reactions reported for arylation via transition metal ...