Micromechanism of ultrahigh pressure extraction of active ingredients from green tea leaves

Research progress and application of pectin: A review

Pectin, an acidic polysaccharide, is naturally present primarily in the cell walls and inner layers of higher plants. Pectin is extensively used in food, pharmaceutical, cosmetic, and other industries owing to its exceptional attributes encompassing superior gelation, emulsification, antioxidant activity, stability, biocompatibility, and nontoxicity. Due to the increasing demand for pectin, there is a short supply in the domestic pectin market. Currently, the domestic production of pectin is heavily reliant on imports, thus emphasizing the urgent need to enhance its local manufacturing capabilities. Due to the diverse sources of pectin and variations in extraction and purification methods, its content, physicochemical properties, and biological activity are influenced, consequently impacting the market application of pectin. Therefore, this paper comprehensively reviews the extraction and purification process of pectin, in vivo metabolism, and biological activities (including antitumor, immunomodulatory, anti-inflammatory, antioxidant, hypoglycemic and hypolipidemic effects, antimicrobial properties, accelerated wound healing potential, promotion of gastrointestinal peristalsis, and alleviation of constipation as well as cholesterol-lowering effect). Furthermore, it explores the diverse applications of pectin in food science, biomedicine, and other interdisciplinary fields. This review serves as a valuable resource for enhancing the efficiency of pectin content improvement and exploring the potential value and application of pectin in a more scholarly and scientifically rigorous manner.

A review on polysaccharide biosynthesis in Cordyceps militaris

Cordyceps militaris (C. militaris) is an edible parasitic fungus with medicinal properties. Its bioactive polysaccharides are structurally diverse and exhibit various metabolic and biological activities, including antitumor, hypoglycemic, antioxidant, hypolipidemic, anti-inflammatory, immunostimulatory, and anti-atherosclerotic effects. These properties make C. militaris-derived polysaccharides a promising candidate for future development. Recent advancements in microbial fermentation technology have enabled successful laboratory cultivation and extraction of these polysaccharides. These polysaccharides are structurally diverse and exhibit various biological activities, such as immunostimulatory, antioxidant, antitumor, hypolipidemic, and anti-atherosclerotic effects. This review aims to summarize the structure and production mechanisms of polysaccharides from C. militaris, covering extraction methods, key genes and pathways involved in biosynthesis, and fermentation factors that influence yield and activity. Furthermore, the future potential and challenges of utilizing polysaccharides in the development of health foods and pharmaceuticals are addressed. This review serves as a valuable reference in the fields of food and medicine, and provides a theoretical foundation for the study of polysaccharides.

Green leaf proteins: a sustainable source of edible plant-based proteins

The rise in the global population, which is projected to reach 9.7 billion by 2050, has resulted in an increased demand for proteins in the human diet. The green leaves of many plants are an affordable, abundant, and sustainable source of proteins suitable for human consumption. This article reviews the various sources of green leaf proteins that may play an important role in alleviating global malnutrition, including those from alfalfa, amaranth, cabbage, cassava, duckweed, moringa, olive, radish, spinach, sugar beet, and tea. The structure of green leaves and the location of the proteins within these leaves are described, as well as methods for extracting and purifying these proteins. The composition, nutritional profile, and functional attributes of green leaf proteins are then discussed. The potential advantages and disadvantages of using green leaf proteins as functional food ingredients are highlighted. The importance of obtaining a better understanding of the composition and structure of different green leaves and the proteins extracted from them is highlighted. This includes an assessment of non-protein nitrogen and anti-nutritional compounds that may be present. Furthermore, the impact of isolation and purification techniques on the functionality of the plant protein ingredients obtained must be carefully evaluated.

High hydrostatic pressure treatment induced microstructure changes and isothiocyanates biosynthesis in kale

Effects of high-pressure processing (HPP) on the myrosinase activity, glucosinolate (GLS) content, isothiocyanate (ITC) conversion rate, color, and bacterial count of kale leaves were investigated. Thermal process at 100 °C were used as negative control groups. The sample processed at 600 MPa exhibited the highest myrosinase activity and ITC conversion rate of 70.4%, while the GLS content was significantly lower than those in the raw and the thermally processed samples. However, processing of the samples at elevated temperatures results in gradual loss of myrosinase activity. SEM images showed that HPP induces irregular crushing damage to the veins, edges, and surfaces of the leaves, thereby promoting the conversion process in the myrosinase-GLS-ITC system. Additionally, HPP caused less significant color change of the kale leaves than thermal treatment. HPP achieved the same level of pasteurization as thermal treatment in terms of bacterial count.

Improving the Extraction of Catechins of Green Tea (Camellia sinensis) by Subcritical Water Extraction (SWE) Combined with Pulsed Electric Field (PEF) or Intense Pulsed Light (IPL) Pretreatment

The aim of this study was to find the optimum condition of pulsed electric field (PEF) and intense pulsed light (IPL) for the enhancement of subcritical water extraction (SWE), which is an eco-friendly extraction method, for extracting tea catechins from green tea leaves (Camellia sinensis). The leaves were treated with PEF under conditions of electric field strength (1, 2 and 3 kV/cm) during 60 s. Moreover, IPL was applied at various voltages (800, 1000, and 1200 V) for 60 s. The SWE was performed for 5 min at varying temperatures (110, 130, 150, 170, and 190 °C). The maximum yield of total catechin was 44.35 ± 2.00 mg/g dry green tea leaves at PEF treatment conditions of 2 kV/cm during 60 s, as well as the SWE temperature of 130 °C. In the case of IPL treatment, the largest amount of total catechin was 48.06 ± 5.03 mg/g dry green tea leaves at 800 V during 60 s when the extraction temperature was 130 °C. The total catechin content was increased by 15.43% for PEF and 25.09% for IPL compared to the value of untreated leaves. This study verified that PEF and IPL had a positive effect on the enhancement of tea catechins extraction from green tea leaves using SWE.

Health Benefits and Chemical Composition of Matcha Green Tea: A Review

Japanese matcha is a type of powdered green tea, grown in a traditional way. Shading of the plants during the growth period enhances the processes of synthesis and accumulation of biologically active compounds, including theanine, caffeine, chlorophyll and various types of catechins. Green tea contains four main catechins, i.e., (-)-epicatechin (EC), (-)-epicatechin-3-gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin-3-gallate (EGCG), of which the latter is the most active and abundant and matcha is their best condensed source. Due to its unique chemical composition and prized flavour, which sets it apart from other tea beverages, it is considered the highest quality tea. Its health-promoting properties are attributed to the high content of antioxidant and anti-inflammatory substances. Studies confirming the high antioxidant potential of tea beverages claim that it originates from the considerable content of catechins, a type of phenolic compound with beneficial effects on human health. Due to its potential for preventing many diseases and supporting cognitive function, regular consumption of matcha may have a positive effect on both physical and mental health. The aim of this review was to compile the health benefits of matcha tea. It is the first such review to be undertaken, and presents its main bioactive compounds in a systematic manner.

Enhanced Antioxidant Capacity of Puffed Turmeric (Curcuma longa L.) by High Hydrostatic Pressure Extraction (HHPE) of Bioactive Compounds

Turmeric (Curcuma longa L.) is known for its health benefits. Several previous studies revealed that curcumin, the main active compound in turmeric, has antioxidant capacity. It has been previously demonstrated that puffing, the physical processing using high heat and pressure, of turmeric increases the antioxidant and anti-inflammatory activities by increasing phenolic compounds in the extract. The current study sought to determine if high hydrostatic pressure extraction (HHPE), a non-thermal extraction at over 100 MPa, aids in the chemical changes and antioxidant functioning of turmeric. 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) analyses were conducted and assessed the content of total phenol compounds in the extract. The chemical changes of curcuminoids were also determined by high performance liquid chromatography (HPLC). Among the three variables of ethanol concentration, pressure level, and treatment time, ethanol concentration was the most influential factor for the HHPE of turmeric. HHPE at 400 MPa for 20 min with 70% EtOH was the optimal extraction condition for the highest antioxidant activity. Compositional analysis revealed that 2-methoxy-4-vinylphenol was produced by puffing. Vanillic acid and ferulic acid content increased with increasing HHPE time. Synergistic effect was not observed on antioxidant activity when the turmeric was sequentially processed using puffing and HHPE.

Trends in the extraction, purification, characterisation and biological activities of polysaccharides from tropical and sub-tropical fruits - A comprehensive review

Tropical and sub-tropical fruits are tremendous sources of polysaccharides (PSs), which are of great interest in the human welfare system as natural medicines, food and cosmetics. This review paper aims to highlight the recent trends in extraction (conventional and non-conventional), purification and analytic techniques of fruit polysaccharides (FPSs). The chemical structure and biological activities, such as immunomodulatory, anti-cancer, anti-oxidant, anti-inflammatory, anti-viral, anti-coagulant and anti-diabetic effects, of PSs extracted from 53 various fruits were compared and discussed. With this wide coverage, a total of 172 scientific articles were reviewed and discussed. This comprehensive survey from previous studies suggests that the FPSs are non-toxic and highly biocompatible. In addition, this review highlights that FPSs might be excellent functional foods as well as effective therapeutic drugs. Finally, the future research advances of FPSs are also described. The content of this review will promote human wellness-based food product development in the future.

Antimicrobial and Fermentation Potential of Himanthalia elongata in Food Applications

Himanthalia elongata is a brown oceanic seaweed rich in bioactive compounds. It could play an important role in food production because of its antimicrobial and antioxidant properties. Three strains belonging to the Lactobacillus casei group (Lactobacillus casei, Lactobacillus paracasei, and Lactobacillus rhamnosus) and a Bacillus subtilis strain were used for the solid-state fermentation of commercial seaweeds, and bacterial growth was monitored using the plate count method. High-pressure processing (HPP) was also employed (6000 bar, 5 min, 5 °C) before extraction. The antimicrobial activity of the extracts was tested in terms of the main food pathogenic bacteria (Salmonella spp., Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, and Bacillus cereus), and the phenolic content was estimated using the Folin-Ciocalteau method. In addition, targeted UHPLC-MS² methods were used to unravel the profile of phlorotannins. H. elongata allowed the growth of the L. casei group strains and B. subtilis, showing the fermentability of this substrate. Significant antimicrobial activity toward L. monocytogenes was observed in the extracts obtained from unfermented samples, but neither fermentation nor HPP enhanced the natural antimicrobial activity of this seaweed species. The content in the phenolic compounds decreased because of the fermentation process, and the amount of phenolics in both the unfermented and fermented H. elongata extracts was very low. Despite phlorotannins being related to the natural antimicrobial activity of this brown seaweed, these results did not support this association. Even if fermentation and HPP were not proven to be effective tools for enhancing the useful compounds of H. elongata, the seaweed was shown to be a suitable substrate for L. casei group strains as well as for B. subtilis growth, and its extracts exhibited antimicrobial activity toward foodborne pathogens.

Extraction of bioactive ingredients from fruiting bodies of Antrodia cinnamomea assisted by high hydrostatic pressure

The aim of this study was to use high hydrostatic pressure treatment to enhance the extraction efficiency of the active components from the fruiting bodies of Antrodia cinnamomea, and compare with those obtained by shake and ultrasonic extraction methods. The conditions of high pressure extraction (HPE) at 600 MPa, a liquid/solid ratio of 40:1, and 3 min of treatment yielded triterpenoids and adenosine concentrations of 410.41 mg/100 mL and 0.47 mg/100 mL, respectively, which did not differ significantly from those with the two other treatments-shake extraction at 180 rpm for 8 h and ultrasonic extraction at 50 Hz for 60 min. The HPE extracts significantly attenuated reactive oxygen species, nitric oxide and prostaglandin E₂ production in lipopolysaccharide-stimulated RAW 264.7 cells than shake extracts did. SEM micrographs revealed that high-pressure caused physical morphological damage to the mycelium of fruiting bodies, such as distortion and disruption of mycelial cells, and increased the mass-transfer effectiveness of the solvent and solute. HPE can be employed as an efficient extraction technique for production of bioactive ingredients that might have a potential application in food and related industries.

Enhancement of Bioactivity of Natural Extracts by Non-Thermal High Hydrostatic Pressure Extraction

Natural extracts, like those obtained from medicinal herbs, dietary plants and fruits are being recognized as important sources of bioactive compounds with several functionalities including antioxidant, anticancer, and antimicrobial activities. Plant extracts rich in phenolic antioxidants are currently being successfully used for several pharmaceutical applications and in the development of new foods (i.e., functional foods), in order to enhance the bioactivity of the products and to replace synthetic antioxidants. The extraction method applied in the recovery of the bioactive compounds from natural materials is a key factor to enhance the bioactivity of the extracts. However, most of the extraction techniques have to employ heat, which can easily lead to heat-sensitive compounds losing their biological activity, due to changes caused by temperature. Presently, high hydrostatic pressure (HHP) is being increasingly explored as a cold extraction method of bioactive compounds from natural sources. This non-thermal high hydrostatic pressure extraction (HHPE) technique allows one to reduce the extraction time and increase the extraction of natural beneficial ingredients, in terms of nutritional value and biological activities and thus enhance the bioactivity of the extracts. This review provides an updated and comprehensive overview on the extraction efficiency of HHPE for the production of natural extracts with enhanced bioactivity, based on the extraction yield, total content and individual composition of bioactive compounds, extraction selectivity, and biological activities of the different plant extracts, so far studied by extraction with this technique.

Ultrahigh pressure extraction of bioactive compounds from plants-A review

Extraction of bioactive compounds from plants is one of the most important research areas for pharmaceutical and food industries. Conventional extraction techniques are usually associated with longer extraction times, lower yields, more organic solvent consumption, and poor extraction efficiency. A novel extraction technique, ultrahigh pressure extraction, has been developed for the extraction of bioactive compounds from plants, in order to shorten the extraction time, decrease the solvent consumption, increase the extraction yields, and enhance the quality of extracts. The mild processing temperature of ultrahigh pressure extraction may lead to an enhanced extraction of thermolabile bioactive ingredients. A critical review is conducted to introduce the different aspects of ultrahigh pressure extraction of plants bioactive compounds, including principles and mechanisms, the important parameters influencing its performance, comparison of ultrahigh pressure extraction with other extraction techniques, advantages, and disadvantages. The future opportunities of ultrahigh pressure extraction are also discussed.

Enzyme and high pressure assisted extraction of tricin from rice hull and biological activities of rice hull extract

Enzymatic hydrolysis was performed in conjunction with high hydrostatic pressure (HPP) treatment to extract tricin from rice hull. Enzymatic hydrolysis performed with Celluclast (0.5%, w/w) prior to HPP (500 MPa) treatment yielded maximum tricin content (32.9 mg/kg rice hull). The tricin content obtained by conventional solvent extraction and HPP treatment alone were 14.7 and 19.7 mg/kg rice hull, respectively. The rice hull extract containing tricin displayed antioxidant, anti-inflammatory, and antiadipogenic activities. The efficacy of rice hull extract obtained by either HPP or combination of enzymatic hydrolysis and HPP treatments was significantly greater than that of extract prepared by traditional solvent extraction.

Efficient extraction strategies of tea (Camellia sinensis) biomolecules

Tea is a popular daily beverage worldwide. Modulation and modifications of its basic components like catechins, alkaloids, proteins and carbohydrate during fermentation or extraction process changes organoleptic, gustatory and medicinal properties of tea. Through these processes increase or decrease in yield of desired components are evident. Considering the varied impacts of parameters in tea production, storage and processes that affect the yield, extraction of tea biomolecules at optimized condition is thought to be challenging. Implementation of technological advancements in green chemistry approaches can minimize the deviation retaining maximum qualitative properties in environment friendly way. Existed extraction processes with optimization parameters of tea have been discussed in this paper including its prospects and limitations. This exhaustive review of various extraction parameters, decaffeination process of tea and large scale cost effective isolation of tea components with aid of modern technology can assist people to choose extraction condition of tea according to necessity.

Polyphenols from fresh frozen tea leaves (Camellia assamica L.,) by supercritical carbon dioxide extraction with ethanol entrainer - application of response surface methodology

Fresh frozen tea leaves (Camellia assamica L.) were extracted with SC-CO2 to obtain polyphenols rich in EGCG and compared with conventional solvent extraction. Extraction parameters such as temperature, pressure and solvent to material ratio were critical factors in extraction and optimized by response surface methodology (RSM). The maximum yield of extractable solids using SC-CO2 with ethanol entrainer was carried out at pressures 150 to 350 bar, temperatures from 40 °C to 60 °C and solvent to material ratio 100 to 200. The theoretical yield was 3.91 % (w/w), while experimental yield was 4.20 ± 0.27 % (w/w) at temperature of 50 °C, pressure 250 bar and solvent to material ratio of 200. The chemical compositions of extracted solids were investigated by HPLC which showed 722.68-848.09 ± 1.12 mg of EGCG/g of extractable solids were separated in SC-CO2. Also, 54.62 ± 1.19 mg of EGCG/g of extractable solids was separated using conventional extraction which is quantitatively lesser than SC-CO2 extraction yield. Thus, SC-CO2 extraction was proved to be effective technique in obtaining extracts rich in EGCG (>95 %).

Changes in the structure and antioxidant properties of onions by high pressure treatment

Onions have antioxidant properties and they are an important source of bioactive compounds such as phenols. The aim of this work was to study the effect of high hydrostatic pressure (HHP) (100-600 MPa/1-3 min/25 °C) on the microstructure and antioxidant properties of onions (cv. Doux) and its relationship with changes in the extractability of potential health-related compounds. Cryo scanning electron microscopy was used to study the microstructure. Vitamin C, total phenolic content and antioxidant activity (DPPH˙, ABTS˙(+), FRAP) were also analyzed. Tonoplast, plasmalemma and cell walls were affected by the HHP treatment and it favored the diffusion of the cellular content to the intercellular spaces. Vitamin C did not show significant changes, whereas the extracted phenolic content and antioxidant activity increased at pressures of 300 or 600 MPa. Therefore, it could be concluded that HHP produced changes in membrane permeability and disruption of cell walls favoring the release of phenolic compounds from tissue and, in consequence, improving their extractability.