# Properties of Green Tea Waste as Cosmetics Ingredients and Rheology Enhancers
###### Abstract  
Green tea waste (GTW) is a naturally abundant material, and it has not been widely reused into more valuable materials. The composition of GTW was identified using NMR for carbohydrate composition, an element analyzer for protein content, acetone and hot water extraction for evaluating extractives, and Klason lignin for lignin content. GTW can be converted into nanoparticles by carboxymethylylation as pretreatment of the degree of substitutions (DS) and high-pressure homogenizer for nanoparticle making. GTW was prepared using various DS 0 until DS 0.4. The results showed that GTW DS has a more than \(-30\) mV zeta potential, suitable for stable nanemulsion formulations. The particle size of GTW DS decreases with increasing carboxyl content in the hydrogel, which has a width and length from GTW DS 0.3 to DS 0.4. As a humectant, the water retention value (WRV) of GTW with various DS was increased; DS 0.3 is the best. DS 0.4 has the highest viscosity, storage, and loss modulus as rheology modifiers. carboxymethylation; green tea waste; high-pressure homogenizer; humectant; nanoparticle; natural cosmetics +
Footnote †: journal: Medical  
changed [14]. The processing method of tea stems is to collect the tea stems in bags and use them to absorb peculiar smells instead of activated carbon [6]. People can also place it in a new car or newly renovated room to remove odors [6]. Tea dregs treatment is more difficult than the stem of tea [3]. In 2012, Japan's famous tea beverage company \"ITOEN\" produced 51,000 tons of tea residue from tea beverage processing [6]. The residue was processed into compost with around 65%, 17% heat recovery, and the rest was used as feed or additive [6]. Although various studies on tea waste have had several results, most have focused on one type of tea waste [15]. They do not provide effective and systematic solutions. Tea residue and tea stems differ from each other as waste [16]. In another way, the pyrolysis carbon from green tea leaves is a potential candidate for use as a high-performance Lithium-Ion Battery [LIB] anode material [16]. In 100 g of green tea, the water-soluble content is 9.07 g phenolic and 28.16 mg ascorbate [17]. At dried weight, the green tea chemical contains 15-20% proteins, 5-7% carbohydrates, 5% minerals and trace elements, and 1-4% amino acids. In recent years, many medical and scientific studies have shown that green tea has antioxidant effect, antiviral, antibacterial, antimutagenic, chemopre effective, and antiproliferative [18; 19; 20]. Commercial tea comprises 3-6% caffeine and 25-40% polyphenols containing flavanols, flavonols, flavanones, and phenolic acids [19; 20; 21; 22]. Tea flavonoids can protect against different types of cancer [19; 21]. Tea residue is well of in polysaccharides [including cellulose and hemicellulose], lignin, pigments, theanine, polyphenols, caffeine, polyphenols, tea saponin, and vitamins [19; 21]. Cellulose is the most abundant biopolymer on earth, with productivity reaching ten tones/year shows myriad potential applications in the energy sector, advanced material, medical and personal care field, environment issues, and food industry sector [23; 24]. Cellulose is responsible for reinforcing the wood cell wall and protecting the organelle of the wood cell [25]. Due to its complex structure in wood cell walls interlinked with lignocellulosic components, it is challenging to obtain pure, high-purity cellulose [26]. Recently, studies have focused on the extraction of cellulose in nano-dimension structure, which further categorizes the cellulose into several nomenclatures such as cellulose nanofibrils (CNF), cellulose nanocrystals (CNC), and micro fibrillated cellulose (MFC). Those variations depend on the methods used to isolate the cellulose [27]. Food side streams, or food byproducts, are already established as a source of natural ingredients. Some ingredients, such as palm kernel oil, are widely used in cosmetic and personal care products.