Phenolic compounds of green tea: Health benefits and technological application in food

Potentialities of Tannase-Treated Green Tea Extract in Nutraceutical and Therapeutic Applications

Green tea has garnered widespread interest in the past decades due to its content of health-beneficial polyphenols and catechins, besides reportedly exhibiting activities for the prevention, and possibly treatment, of many modern-life-associated afflictions. Hence, the functional food potential of health-beneficial beverages such as green tea is widely and commercially promoted. Biotransformation of green tea extract using enzymes such as tannase ostensibly enhances its beneficial well-being properties and disease-preventing functionalities. The tannase-treated green tea catechins may exhibit enhanced, amongst others, antioxidant, anti-tumour, anti-wrinkle, anti-inflammatory, anti-obesity and anti-sarcopenia properties compared to native green tea extract. Nonetheless, the health benefits and therapeutic and toxicological effects associated with these compounds, before and after tannase treatment, present a scientific gap for detailed studies. Accordingly, the review surveys the literature from the late twentieth century until the year 2023 related to the aforementioned important aspects.

Optimizing catechin extraction from green tea waste: Comparative analysis of hot water, ultrasound-assisted, and ethanol methods for enhanced antioxidant recovery

This study aimed to develop an efficient method for the extraction of bioactive compounds from green tea waste (GTW) toward its potential application in the food industry. GTW, which is generated during the harvesting and processing of green tea products, accounts for a global annual loss of nearly 1 million tonnes. Notably, this waste is rich in polyphenolic compounds, particularly catechins, which are renowned for their significant health benefits. We assessed the optimization of catechin extraction from GTW employing hot water extraction (HWE), ultrasound-assisted extraction (UAE), and ethanol extraction (EthE) techniques at different sample-to-solvent ratios (1:100, 1:50, and 1:20 w/v). The extraction temperature was set at 80°C for both HWE and UAE; however, for EthE, the temperature was slightly lower at 70°C, adhering to the boiling point of ethanol. High-performance liquid chromatography was used to determine the extraction efficiency by quantifying various catechins (i.e., catechin, epicatechin [EC], epicatechin gallate [ECG], epigallocatechin [EGC], and epigallocatechin gallate [EGCG]). In terms of the concentration for individual catechins, EC was found to be the highest concentration detected, ranging from 30.58 ± 1.17 to 37.95 ± 0.84 mg/L in all extraction techniques and ratios of solvents, followed by EGCG (9.71 ± 1.40-20.99 ± 1.11 mg/L), EGC + C (7.95 ± 0.66-12.58 ± 0.56 mg/L), and ECG (1.85 ± 0.71-6.05 ± 0.06 mg/L). The findings of DPPH (2,2-diphenyl-1-picryl-hydrazyl) free radical assay illustrated that HWE demonstrated the highest extraction efficiency at all ratios, ranging from 61.41 ± 1.00 to 70.36 ± 1.47 mg/L. The 1:50 ratio exhibited the highest extraction yield (25.98% ± 0.75%) compared to UAE (24.16% ± 0.95%) and EthE (22.59% ± 0.26%). Moreover, this method of extraction (i.e., HWE) produced the highest total catechins and %DPPH reduction. Consequently, HWE was the most efficient method for extracting catechins from GTW, underscoring its potential for valorizing waste within the food manufacturing industry.

Effects of Different Phenolic Compounds on the Redox State of Myoglobin and Prevention of Discoloration, Lipid and Protein Oxidation of Refrigerated Longtail Tuna (Thunnus tonggol) Slices

Effects of different phenolic compounds on the redox state of myoglobin and their potential for preserving the color and chemical quality of refrigerated longtail tuna (Thunnus tonggol) slices were studied. Purified myoglobin from dark muscle (15.83 kDa) was prepared. Catechin, EGCG, quercetin, and hyperoside affected the absorption spectra and redox state of metmyoglobin (metMb) at 4 °C for up to 72 h differently. Reduction of metMb to oxymyoglobin (oxyMb) was notably observed for two flavonols (EGCG and quercetin) at 50 and 100 ppm. Based on the reducing ability of metMb, EGCG and quercetin were selected for further study. Longtail tuna slices were treated with EGCG and quercetin at 200 and 400 mg/kg. Color (a* and a*/b*), proportion of myoglobin content, and quality changes were monitored over 72 h at 4 °C. Tuna slices treated with 200 mg/kg EGCG showed better maintenance of oxyMb and color as well as lower lipid oxidation (PV and TBARS) and protein oxidation (carbonyl content) than the remaining samples. Nevertheless, EGCG at 400 mg/kg exhibited lower efficacy in retaining the quality of tuna slices. Thus, EGCG at 200 mg/kg could be used to maintain the color and prolong the shelf life of refrigerated longtail tuna slices.

Effects of adding green tea extract on the oxidative stability and shelf life of sunflower oil during storage

This study aimed to compare different concentrations effect of green tea extract (GTE) (200, 400, and 800 ppm) with TBHQ (75 ppm) in extend the shelf-life of sunflower oil (SO) and to evaluate the protective effect of GTE on the oxidation of refined SO. The sample's peroxide value (PV), acidity value (AV), anisidine value (pAV), Totox value (TV), oxidative stability, and total phenol content (TPC) were analyzed at specific intervals during 12-month at 25 °C and 60-day at 60 °C. The optimum kinetic model corresponding to the first order for PV, TV, and pAV was obtained at 25, 35, and 45 °C. SO containing GTE (800 ppm) had a similar performance to TBHQ at 25 °C and 60 °C and possessed a longer shelf life than samples treated with TBHQ. Due to synthetic antioxidant's health risk and toxicity, GTE can be a good substitute for TBHQ in the edible oil industry.

Sustainable papaya plant waste and green tea residue composite films integrated with starch and gelatin for active food packaging applications

This study explores the sustainable utilization of wastes from a papaya plant (papaya peels (PP), papaya seeds (PS), leaf-stem (PL)) and dried green tea residues (GTR) for the synthesis of bioplastics. The dried GTR were individually blended with each papaya waste extract and then boiled in water to get three composite papaya plant waste-green tea supernatants. Potato starch and gelatin-based functional films were prepared by integrating each with the composite papaya waste-green tea supernatant liquid. This work introduces a dissolved organic matter (DOM) study to the field of bioplastics, with the goal of identifying the organic components and macromolecules inherent in the PW supernatants. When compared with the films prepared solely from papaya waste (PW) supernatants, PW-GTR composite supernatant films prevent UV light transmission with superior antioxidant and mechanical properties. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction spectroscopy (XRD), and atomic force microscopy (AFM) were utilized to characterize the starch and gelatin PW-GTR films. Owing to the exceptional antioxidant, UV barrier, and remarkable biodegradable properties of the starch/PW/GTR and gelatin/PW/GTR composite films, make them ideal for use in food packaging applications.

Undifferentiated Cells of Tessaria absinthioides with High Nutritional Value and Health-Promoting Phytochemicals. An Approach Based on Plant Cellular Agriculture

In vitro cultures of undifferentiated plant cells of Tessaria absinthioides, a native herb popularly recognized and used for its health benefits, were studied as potential food supplements. These tissues were incubated under two light conditions, and the biomass obtained was freeze-dried and oven-dried. To evaluate their nutritional value, their physicochemical and functional properties were determined. Although in some cases there were significant differences in the results according to the drying methodology applied, all these tissues presented a high proportion of proteins (23.6-28.3%), a low percentage of fats (< 2%) constituted mainly by phytosterols, and a significant amount of crude fibers (6.9-9.0%) and ashes (> 10%). In addition, the freeze-dried calli resulted in a product with better functional properties. On the other hand, their phytochemical profiles and antioxidant capacity were studied and compared with tissues from wild specimens and with green tea and chamomile as reference extracts.

Physicochemical, Antioxidant, and Antimicrobial Properties of Three Medicinal Plants from the Western Part of the Rhodope Mountains, Bulgaria

The present study examined the physicochemical, antioxidant, and antimicrobial properties of three medicinal plants: thyme (Thymus callieri Borbás ex Velen), cotton thistle (Onopordum acanthium L.), and hawthorn fruit (Crataegus monogyna Jacq.) from the Western Rhodope Mountains, Bulgaria. The first stage determined the physicochemical characteristics (moisture, ash, carbohydrates, proteins, and vitamin C) of the three herbs. The second stage investigated four types of extracts (aqueous, oil, methanolic, and ethanolic) of each herb and evaluated their total phenolic content, the presence of phenolic compounds (flavonoids and phenolic acids), their antioxidant activity, and antimicrobial properties. Thyme was characterised by the highest ash, protein, and vitamin C content (6.62%, 11.30%, and 571 mg/100 g, respectively). Hawthorn fruit showed the highest moisture and carbohydrate content (8.50% and 4.20%, respectively). The 70% ethanolic extracts of the three herbs exhibited the highest levels of phenolic compounds and, consequently, pronounced antioxidant activity, compared to the other three types of extracts. The aqueous, oil, methanolic, and ethanolic thyme extracts demonstrated the highest total phenolic content-TPC (27.20 mg GAE/g, 8.20 mg GAE/g, 31.70 mg GAE/g, and 310.00 mg GAE/g, respectively), compared to the extracts of the other two plants. These results were consistent with the highest antioxidant activity of the thyme extracts determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, the oxygen radical absorbance capacity (ORAC) assay, and the hydroxyl radical averting capacity (HORAC) assay (except for the oil extract examined using the DPPH method). The results from the high-performance liquid chromatography (HPLC) analysis revealed that the flavonoid quercetin-3-ß-glucoside had the highest concentration in thyme (374.5 mg/100 g), while myricetin dominated in the cotton thistle (152.3 mg/100 g). The phenolic acid content analysis showed prevalence of rosmaric acid in the thyme (995 mg/100 g), whereas chlorogenic acid was detected in the highest concentration in the cotton thistle and hawthorn fruit (324 mg/100 g and 27.7 mg/100 g, respectively). The aqueous, methanolic, and ethanolic extracts showed moderate to high antibacterial potential but limited antifungal activity. None of the oil extracts inhibited the test microorganisms used in the study.

Investigation of the antimicrobial, antioxidant, hemolytic, and thrombolytic activities of Camellia sinensis, Thymus vulgaris, and Zanthoxylum armatum ethanolic and methanolic extracts

Camellia sinensis is rich in antioxidants such as polyphenols; Thymus vulgaris contains bioactive compounds (flavonoids, terpenoids, and tannins) and Zanthoxylum armatum is primarily composed of volatile oils, amides, alkaloids, flavonoids, lignan, and coumarin. The antibacterial, antifungal, biofilm inhibition, antioxidant, hemolytic, and thrombolytic activities of Camellia sinensis, Thymus vulgaris, and Zanthoxylum armatum ethanol and methanol extracts at different concentrations (30%, 50%, and 80%) were determined. The antioxidant activity and content were measured as free radical scavenging assay (DPPH), total flavonoid content (TFC), and total phenolic content (TPC). Furthermore, hemolytic and thrombolytic analysis was carried out to determine toxicity. In antimicrobial assays, 80% methanol thyme extract showed highest (15.31 mm) antibacterial activity against Bacillus subtilis, and 80% ethanol green tea extract showed optimal antibacterial activity against Staphylococcus aureus. Ethanol 30% green tea extract resulted in highest (26.61 mm) antifungal activity against Aspergillus niger. The maximum (54.73%) biofilm inhibition was resulted by methanol 50% thyme extract for Escherichia coli. In antioxidant activity and content, methanol 50% green tea extract had highest (80.82%) antioxidant activity, whereas, ethanol 80% green tea extract had maximum (1474.55 mg CE/g DW) TFC and methanol 80% green tea extract had maximum (593.05 mg GAE/g) TPC. In toxicological assays, methanol 30% green tea extract had highest (25.28%) thrombolytic activity, and ethanol 80% tejphal extract had maximum (18.24%) hemolytic activity. This study has highlighted the significant antimicrobial, antioxidant, hemolytic, and thrombolytic activities of Camellia sinensis, Thymus vulgaris, and Zanthoxylum armatum extracts that could be beneficial to treat various diseases (cancer, diabetes, and respiratory diseases) and may be utilized as functional ingredient in the preparation of functional foods and drinks.

Tea's anti-obesity properties, cardiometabolic health-promoting potentials, bioactive compounds, and adverse effects: A review focusing on white and green teas

Tea is one of the most commonly consumed beverages in the world. Morocco, Japan, and China have consumed green tea for centuries. White tea, which is a variety of green teas, is very popular in China and is highly revered for its taste. Presently, both teas are consumed in other countries around the world, even as functional ingredients, and novel research is constantly being conducted in these areas. We provide an update on the health benefits of white and green teas in this review, based on recent research done to present. After a general introduction, we focused on tea's anti-obesity and human health-promoting potential, adverse effects, and new approaches to tea and its bioactive compounds. It has been found that the health benefits of tea are due to its bioactive components, mainly phenolic compounds. Of these, catechins are the most abundant. This beverage (or its extracts) has potential anti-inflammatory and antioxidant properties, which could contribute to body weight control and the improvement of several chronic diseases. However, some studies have mentioned the possibility of toxic effects; therefore, reducing tea consumption is a good idea, especially during the last trimester of pregnancy. Additionally, new evidence will provide insight into the possible effects of tea on the human gut microbiota, and even on the viruses responsible for SARS-CoV-2. A beverage such as this may favor beneficial gut microbes, which may have important implications due to the influence of gut microbiota on human health.

Investigation of Chemical Constituents and Antioxidant Activity of Biologically Active Plant-Derived Natural Products

The aim of this publication is to present rapid screening methods (visual/colorimetric) that will enable quick identification of the presence of biologically active compounds in aqueous solutions. For this reason, 26 plant extracts obtained by ultrasound-assisted extraction were analysed for the content of these compounds. Higher plants, used as a raw material for extraction, are common in Europe and are easily available. The article proposes a comparison of various protocols for the identification of various compounds, e.g., phenolic compounds (phenols, tannins, anthocyanins, coumarins, flavones, flavonoids), vitamin C, quinones, quinines, resins, glycosides, sugars. Initial characterisation of the composition of plant extracts using fast and inexpensive methods allows you to avoid the use of time-consuming analyses with the use of advanced research equipment. In addition, the antioxidant activity of plant extracts using spectrophotometric methods (DPPH, ABTS, FRAP assay) and quantitative analysis of plant hormones such as abscisic acid, benzoic acid, gibberellic acid, indole acetic acid, jasmonic acid, salicylic acid, zeatin, zeatin riboside, and isipentenyl adenine was performed. The obtained results prove that the applied visual methods show different sensitivity in detecting the sought chemical compounds. Therefore, it is necessary to confirm the presence or absence of bioactive substances and their concentration using modern analytical methods.

A comprehensive review of nano-delivery system for tea polyphenols: Construction, applications, and challenges

Tea polyphenols (TPs) are important bioactive compounds in tea and have excellent physiological regulation functions. However, the extraction and purification of TPs are key technologies affecting their further application, and the chemical instability, poor bioavailability of TPs are major challenges for researchers. In the past decade, therefore, research and development of advanced carrier systems for the delivery of TPs has been greatly promoted to improve their poor stability and poor bioavailability. In this review, the properties and function of TPs are introduced, and the recent advances in the extraction and purification technologies are systematically summarized. Particularly, the intelligent delivery of TPs via novel nano-carriers is critically reviewed, and the application of TPs nano-delivery system in medical field and food industry is also described. Finally, the main limitations, current challenges and future perspectives are highlighted in order to provide research ideas for exploiting nano-delivery carriers and their application in TPs.

The chemical profiling and assessment of antioxidative, antidiabetic and antineurodegenerative potential of Kombucha fermented Camellia sinensis, Coffea arabica and Ganoderma lucidum extracts

The scientific interest in the medicinal properties of Kombucha beverages, a carbonated drink with live microorganisms, has increased recently. Hence, the aim of this study was to determine the chemical profile and to examine the antioxidant, antidiabetic and antineurodegenerative potential of unfermented and also Kombucha fermented Camellia sinensis (green tea), Coffea arabica (coffee), and Ganoderma lucidum (Reishi) extracts. The extracts were prepared as follows: the first (unfermented) set contained 1 L of water, 50 g of sucrose and 20 g of dried and ground green tea, coffee, or Reishi basidiocarp, while the second (fermented) set contained all of the aforementioned ingredients individually inoculated with Kombucha and fermented for 21 days. The chemical analysis was conducted using liquid chromatography-mass spectrometry (LC-MS). The antioxidant activity was assessed by DPPH, total reducing power (TRP), and β-carotene bleaching assays. The inhibition of α-amylase and α-glucosidase activity was used to estimate the antidiabetic potential, while the level of inhibition of acetylcholinesterase (AChE) and tyrosinase (TYR) was used to evaluate the antineurodegenerative activity. The results suggested that the fermented extracts of green tea, coffee, and Reishi exert significant antioxidant effects, although they were lower compared to the unfermented extracts. The unfermented green tea extract exhibited the highest DPPH-scavenging activity (87.46%) and the highest preservation of β-carotene (92.41%), while the fermented coffee extract showed the highest TRP (120.14 mg AAE per g) at 10 mg mL^-1. Although the extracts did not inhibit the activity of α-amylase, they were quite effective at inhibiting α-glucosidase, especially the unfermented Reishi extract, inhibiting 95.16% (at a concentration of 10 mg mL^-1) of α-glucosidase activity, which was slightly higher than the positive control at the same concentration. The most effective AChE inhibitor was unfermented green tea extract (68.51%), while the fermented coffee extract inhibited 34.66% of TYR activity at 10 mg mL^-1. Altogether, these results are in accordance with the differences found in the extracts' chemical composition. Finally, this is the first report that highlights the differences in the chemical profile between the unfermented and Kombucha fermented green tea, coffee and Reishi extracts, while it also reveals, for the first time, the antineurodegenerative potential of Kombucha fermented Reishi extract. The examined extracts represent potent functional foods, while their more detailed mechanisms of action are expected to be revealed in future research.

Green tea could improve elderly hypertension by modulating arterial stiffness, the activity of the renin/angiotensin/aldosterone axis, and the sodium-potassium pumps in old male rats

Hypertension is a major health problem common in the elderly people. Green tea is a popular beverage recommended in folk medicine for lowering blood pressure. However, the molecular mechanisms involved in the antihypertensive effects of green tea are not fully understood. Therefore, the aim of this study was to investigate the antihypertensive effects of green tea on high-salt diet-induced hypertension in old male rats. Forty old male rats were divided into five groups: control, hypertensive, and hypertensive-green tea (2, 4, and 6 g/kg). Heart rate (HR) and systolic blood pressure (SBP) were measured. Cardiac and renal histology were also performed. Lipid profile, NO, angiotensin II (Ang II), and aldosterone were determined, and the expression of eNOS, ATIR and ATIIR, aldosterone receptor, and Atp1a1 were measured. Green tea could significantly decrease HR and SBP, lipid profiles, renin-angiotensin II-aldosterone system activity, and Ang II signaling in kidney tissue of hypertensive rats (p < .01). It also increased Atp1a1, Nrf2, and eNOS expression along with antioxidant enzymes activity and NO concentration (p < .05) and decreased NF-ĸB and iNOS expression and IL-1β levels in the heart, kidneys, and aorta of rats with hypertension. It can be concluded that green tea can improve salt-induced blood pressure by modulating the function of the renin-angiotensin-aldosterone system, enhancing the synthesis of nitric oxide in the endothelium, increasing antioxidant activity and suppressing inflammation in the heart and kidney, improving the expression of the sodium-potassium pump, and reduction in serum lipids and glucose in aged male rats. PRACTICAL APPLICATIONS: The results of this study showed that green tea could improve hypertension in elderly rats by modulating (1) the expression of the sodium-potassium pump in the heart, kidney, and aortic tissues, (2) the activity of the renin-angiotensin II-aldosterone system in kidney, (3) enhancing antioxidant and anti-inflammatory activities in the heart, aorta, and kidneys, (4) enhancing the synthesis of nitric oxide in the endothelium, and (5) lowering lipid profile. The results of these studies show that the consumption of green tea and its products can be a good candidate for the prevention of cardiovascular diseases such as hypertension in the elderly. In addition, attention to its bioactive compounds can be considered by researchers as an independent therapeutic strategy or adjunctive therapy for the treatment of hypertension.

The Effects of the Cultivar and Environment on the Phenolic Contents of Hazelnut Kernels

Different climatic conditions are known to affect the synthesis of primary and secondary metabolites. Therefore, the phenolic contents in new growing areas could affect the quality and flavor of hazelnuts. The aim of this study was to determine the variability of the phenolic contents of the kernels in different commercial hazelnut cultivars depending on their growing area. Five cultivars ('Tonda Gentile delle Langhe', 'Merveille de Bollwiller', 'Pauetet', 'Tonda di Giffoni', and 'Barcelona' (syn. 'Fertile de Coutard')) grown in different European collection orchards were included in the study. High-performance liquid chromatography coupled with mass spectrometry was used to identify and quantify the phenolic compounds. Thirteen phenols were identified in the hazelnut kernels, including 7 flavanols, 2 hydroxybenzoic acids, 3 flavonols, and one dihydrochalcone. Catechin and procyanidin dimers were the main phenolic compounds found in the hazelnut kernels. The highest contents of catechin and total flavanols were determined in cultivars cultivated in Spain and northern Italy, and the lowest in Slovenia and France. Flavanols were the major phenolic groups independent of the place of cultivation, as they accounted for more than 50% of all phenolic compounds identified. The flavanols were followed by hydroxybenzoic acids, flavonols, and dihydrochalcones. Higher contents of flavanols and flavonols were found in kernels from areas characterized by higher natural irradiation, which stimulates their accumulation. The contents of hydroxybenzoic acids correlated with altitude, which stimulated phenolic acid synthesis. A negative correlation was observed between the dihydrochalcone content and annual rainfall, probably due to hydric stress.

Essential Oil Variability in Iranian Populations of Heracleum persicum Desf. ex Fischer: A Rich Source of Hexyl Butyrate and Octyl Acetate

Heracleum persicum Desf. ex Fischer seeds are a rich source of essential oils (EOs) with high antimicrobial and antioxidant effects. In order to determine the phytochemical variability in various Iranian H. persicum populations, seed samples were collected from 10 different climatic locations. The current study indicated that hexyl butyrate (20.9–44.7%), octyl acetate (11.2–20.3%), hexyl-2-methylbutyrate (4.81–8.64%), and octyl 2-methyl butyrate (3.41–8.91%) were the major components of the EOs. The maximum (44.7%) and the minimum (20.9%) content of hexyl butyrate were obtained from Kaleibar and Sari populations, respectively. Moreover, the octyl acetate content ranged from 2% (in Mahdasht) to 20.3% in Torghabeh population. The CA and PCA analysis divided the 10 Iranian H. persicum populations into three major groups. Populations from Khanghah, Kaleibar, Shebeilo, Showt, Mahdasht, and Amin Abbad showed a distinct separation in comparison with the other populations, having high contents of hexyl butyrate (39.8%) and low contents of octyl acetate (13.5%) (Chemotype II). According to correlation analysis, the highest correlation coefficient was among habitat elevation and hexyl butyrate content. In addition, the mean annual precipitation was negatively correlated with the content of hexyl butyrate. Although octyl acetate content showed high correlation with soil EC and mean annual temperature, it was not statistically significant. In general, in order to have plants with a high content of hexyl butyrate, it is recommended to harvest these plants from regions with high altitude and low rainfall such as Kaleibar.

The Release of Non-Extractable Ferulic Acid from Cereal By-Products by Enzyme-Assisted Hydrolysis for Possible Utilization in Green Synthesis of Silver Nanoparticles

The present work was undertaken to elucidate the potential contribution of biosynthetically produced ferulic acid (FA) via enzymatic hydrolysis (EH) of rye bran (RB) to the formation of silver nanoparticles (AgNPs) during green synthesis. An analytical approach accomplished by multiple reaction monitoring (MRM) using triple quadrupole mass selective detection (HPLC-ESI-TQ-MS/MS) of the obtained hydrolysate revealed a relative abundance of two isomeric forms of FA, i.e., trans-FA (t-FA) and trans-iso-FA (t-iso-FA). Further analysis utilizing high-performance liquid chromatography with refractive index (HPLC-RID) detection confirmed the effectiveness of RB EH, indicating the presence of cellulose and hemicellulose degradation products in the hydrolysate, i.e., xylose, arabinose, and glucose. The purification process by solid-phase extraction with styrene-divinylbenzene-based reversed-phase sorbent ensured up to 116.02 and 126.21 mg g-1 of t-FA and t-iso-FA in the final eluate fraction, respectively. In the green synthesis of AgNPs using synthetic t-FA, the formation of NPs with an average size of 56.8 nm was confirmed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) techniques. The inclusion of polyvinylpyrrolidone (PVP-40) in the composition of NPs during synthesis favorably affected the morphological features, i.e., the size and shape of AgNPs, in which as big as 22.4 nm NPs were engineered. Meanwhile, nearly homogeneous round-shaped AgNPs with an average size of 16.5 nm were engineered using biosynthetically produced a mixture of t-FA and t-iso-FA and PVP-40 as a capping agent. The antimicrobial activity of AgNPs against Gram-positive and Gram-negative bacteria, including Pseudomonas aeruginosa, E. coli, Enterococcus faecalis, Bacillus subtilis, and Staphylococcus aureus was confirmed by the disk diffusion method and additionally supported by values of minimum inhibitory (MIC) and bactericidal (MBC) concentrations. Given the need to reduce problems of environmental pollution with cereal processing by-products, this study demonstrated a technological solution of RB rational use in the sustainable production of AgNPs during green synthesis. The AgNPs can be considered as active pharmaceutical ingredients (APIs) to be used for developing new antimicrobial agents and modifying therapies in treating multi-drug resistant (MDR) pathogens.

Fermented Soy Products and Their Potential Health Benefits: A Review

In the growing search for therapeutic strategies, there is an interest in foods containing natural antioxidants and other bioactive compounds capable of preventing or reversing pathogenic processes associated with metabolic disease. Fermentation has been used as a potent way of improving the properties of soybean and their components. Microbial metabolism is responsible for producing the β-glucosidase enzyme that converts glycosidic isoflavones into aglycones with higher biological activity in fermented soy products, in addition to several end-metabolites associated with human health development, including peptides, phenolic acids, fatty acids, vitamins, flavonoids, minerals, and organic acids. Thus, several products have emerged from soybean fermentation by fungi, bacteria, or a combination of both. This review covers the key biological characteristics of soy and fermented soy products, including natto, miso, tofu, douchi, sufu, cheonggukjang, doenjang, kanjang, meju, tempeh, thua-nao, kinema, hawaijar, and tungrymbai. The inclusion of these foods in the diet has been associated with the reduction of chronic diseases, with potential anticancer, anti-obesity, antidiabetic, anticholesterol, anti-inflammatory, and neuroprotective effects. These biological activities and the recently studied potential of fermented soybean molecules against SARS-CoV-2 are discussed. Finally, a patent landscape is presented to provide the state-of-the-art of the transfer of knowledge from the scientific sphere to the industrial application.

Recent advances in biobased and biodegradable polymer nanocomposites, nanoparticles, and natural antioxidants for antibacterial and antioxidant food packaging applications

Inorganic nanoparticles (NPs) and natural antioxidant compounds are an emerging trend in the food industry. Incorporating these substances in biobased and biodegradable matrices as polysaccharides (e.g., starch, cellulose, and chitosan) and proteins has highlighted the potential in active food packaging applications due to more significant antimicrobial, antioxidant, UV blocking, oxygen scavenging, water vapor permeability effects, and low environmental impact. In recent years, the migration of metal NPs and metal oxides in food contact packaging and their toxicological potential have raised concerns about the safety of the nanomaterials. In this review, we provide a comprehensive overview of the main biobased and biodegradable polymer nanocomposites, inorganic NPs, natural antioxidants, and their potential use in active food packaging. The intrinsic properties of NPs and natural antioxidant actives in packaging materials are evaluated to extend shelf-life, safety, and food quality. Toxicological and safety aspects of inorganic NPs are highlighted to understand the current controversy on applying some nanomaterials in food packaging. The synergism of inorganic NPs and plant-derived natural antioxidant actives (e.g., vitamins, polyphenols, and carotenoids) and essential oils (EOs) potentiated the antibacterial and antioxidant properties of biodegradable nanocomposite films. Biodegradable packaging films based on green NPs-this is biosynthesized from plant extracts-showed suitable mechanical and barrier properties and had a lower environmental impact and offered efficient food protection. Furthermore, AgNPs and TiO₂ NPs released metal ions from packaging into contents insufficiently to cause harm to human cells, which could be helpful to understanding critical gaps and provide progress in the packaging field.

Comparative study of phenolic profile, antioxidant and antimicrobial activities of aqueous extract of white and green tea

The sole difference between white tea (WT) and green tea (GT) is the former that made only from the buds and young leaves of the Camelia sinensis plant, whilst the latter is made from matured tea leaves. The phytochemical profiles, phenolic compounds, antioxidant, and antimicrobial activity of two varieties of Camellia sinensis teas, white and green, were compared in this study. Total antioxidant capacity, reducing power, DPPH radical scavenging, and Fe+2 chelating activities were used to determine antioxidant activities in water extract of GT and WT. The largest level of phenolic content was discovered in WGTE compared with the lowest amount was found in WWTE (290.67 mg/100 g tea and 185.96 mg/100 g tea, respectively). Phenoilc acids (gallic, benzoic, chlorogenic, ellagic, and ρ-coumaric acids) and flavonoids (rutin and kampherol) were found in the two extracts. The findings of DPPH radical scavenging assays were 84.06 and 82.37% inhibition. In vitro antimicrobial activity was indicated that (WWTE and WGTE) had a high level of activity against Staphylococcus aureus, and gave negative activity against Salmonella typhimurium, and Aspergillus Niger. The WT and GT extracts are a great source of natural antioxidants with biological effects on human health.

Bioactive compounds: Application of albumin nanocarriers as delivery systems

Enriched products with bioactive compounds (BCs) show the capacity to produce a wide range of possible health effects. Most BCs are essentially hydrophobic and sensitive to environmental factors; so, encapsulation becomes a strategy to solve these problems. Many globular proteins have the intrinsic ability to bind, protect, encapsulate, and introduce BCs into nutraceutical or pharmaceutical matrices. Among them, albumins as human serum albumin (HSA), bovine serum albumin (BSA), ovalbumin (OVA) and α-lactalbumin (ALA) are widely abundant, available, and applied in many industrial sectors, becoming promissory materials to encapsulate BCs. Therefore, this review focuses on researches about the main groups of natural origin BCs (namely phenolic compounds, lipids, vitamins, and carotenoids), the different types of nanostructures based on albumins to encapsulate them and the main fields of application for BCs-loaded albumin systems. In this context, phenolic compounds (catechins, quercetin, and chrysin) are the most extensively BCs studied and encapsulated in albumin-based nanocarriers. Other extensively studied subgroups are stilbenes and curcuminoids. Regarding lipids and vitamins; terpenes, carotenoids (β-carotene), and xanthophylls (astaxanthin) are the most considered. The main application areas of BCs are related to their antitumor, anti-inflammatory, and antioxidant properties. Finally, BSA is the most used albumin to produced BCs-loaded nanocarriers.

Protective Effect of Liposomal Epigallocatechin-Gallate in Experimental Gentamicin-Induced Hepatotoxicity

Our study aimed to assess the effect of liposomal epigallocatechin-gallate (LEGCG) compared with epigallocatechin-gallate (EGCG) solution on hepatic toxicity induced by gentamicin (G) administration in rats. Five groups were evaluated, a control group (no G administration) and four groups that received G (1 mL, i.p, 80 mg/kg b.w. (body weight/day), for 7 days) to which we associated daily administration 30 min before G of EGCG (G-EGCG, 2.5 mg/0.1 kg b.w.), LEGCG (G-LEGCG, 2.5 mg/0.1 kg b.w.) or silymarin (100 mg/kg b.w./day). The nitro-oxidative stress (NOx), catalase (CAT), TNF-α, transaminases, creatinine, urea, metalloproteinase (MMP) 2 and 9, and liver histopathological changes were evaluated. LEGCG exhibited better efficacy than EGCG, improving the oxidant/antioxidant balance (p = 0.0125 for NOx and 0.0032 for CAT), TNF-α (p < 0.0001), MMP-2 (p < 0.0001), aminotransferases (p = 0.0001 for AST and 0.0136 for ALT), creatinine (p < 0.0001), urea (p = 0.0006) and histopathologic liver changes induced by gentamicin. Our study demonstrated the beneficial effect of EGCG with superior results of the liposomal formulation for hepatoprotection in experimental hepatic toxicity induced by gentamicin.

Protective Effect of Liposomal Epigallocatechin-Gallate in Experimental Gentamicin-Induced Hepatotoxicity

Our study aimed to assess the effect of liposomal epigallocatechin-gallate (LEGCG) compared with epigallocatechin-gallate (EGCG) solution on hepatic toxicity induced by gentamicin (G) administration in rats. Five groups were evaluated, a control group (no G administration) and four groups that received G (1 mL, i.p, 80 mg/kg b.w. (body weight/day), for 7 days) to which we associated daily administration 30 min before G of EGCG (G-EGCG, 2.5 mg/0.1 kg b.w.), LEGCG (G-LEGCG, 2.5 mg/0.1 kg b.w.) or silymarin (100 mg/kg b.w./day). The nitro-oxidative stress (NOx), catalase (CAT), TNF-α, transaminases, creatinine, urea, metalloproteinase (MMP) 2 and 9, and liver histopathological changes were evaluated. LEGCG exhibited better efficacy than EGCG, improving the oxidant/antioxidant balance (p = 0.0125 for NOx and 0.0032 for CAT), TNF-α (p < 0.0001), MMP-2 (p < 0.0001), aminotransferases (p = 0.0001 for AST and 0.0136 for ALT), creatinine (p < 0.0001), urea (p = 0.0006) and histopathologic liver changes induced by gentamicin. Our study demonstrated the beneficial effect of EGCG with superior results of the liposomal formulation for hepatoprotection in experimental hepatic toxicity induced by gentamicin.

Protective Effect of Liposomal Epigallocatechin-Gallate in Experimental Gentamicin-Induced Hepatotoxicity

Our study aimed to assess the effect of liposomal epigallocatechin-gallate (LEGCG) compared with epigallocatechin-gallate (EGCG) solution on hepatic toxicity induced by gentamicin (G) administration in rats. Five groups were evaluated, a control group (no G administration) and four groups that received G (1 mL, i.p, 80 mg/kg b.w. (body weight/day), for 7 days) to which we associated daily administration 30 min before G of EGCG (G-EGCG, 2.5 mg/0.1 kg b.w.), LEGCG (G-LEGCG, 2.5 mg/0.1 kg b.w.) or silymarin (100 mg/kg b.w./day). The nitro-oxidative stress (NOx), catalase (CAT), TNF-α, transaminases, creatinine, urea, metalloproteinase (MMP) 2 and 9, and liver histopathological changes were evaluated. LEGCG exhibited better efficacy than EGCG, improving the oxidant/antioxidant balance (p = 0.0125 for NOx and 0.0032 for CAT), TNF-α (p < 0.0001), MMP-2 (p < 0.0001), aminotransferases (p = 0.0001 for AST and 0.0136 for ALT), creatinine (p < 0.0001), urea (p = 0.0006) and histopathologic liver changes induced by gentamicin. Our study demonstrated the beneficial effect of EGCG with superior results of the liposomal formulation for hepatoprotection in experimental hepatic toxicity induced by gentamicin.

Hepatoprotective effects of methanolic extract of green tea against Thioacetamide-Induced liver injury in Sprague Dawley rats

ETHNOPHARMACOLOGICAL RELEVANCE

Since ancient times, herbal medicines have been applied in the treatment of cancer. Tea, derivative from the dried leaves of Camellia sinensis (L.) Kuntze plant is the most popular beverage globally after water and is available in various forms. Green tea has been expansively investigated for its beneficial properties of cancer prevention and therapy. The goal of the research: The current study was conducted to evaluate the hepaprotective character of methanolic green tea extract and its mechanism of action contrary to thioacetamide (TAA)-produced liver fibrosis of Sprague Dawley rats.

MATERIALS AND METHODS

Thirty rodents were equally placed in 5 clusters including normal control, TAA group as a positive control, silymarin as standard drug control, and treatment groups consisting of high dose and a low dose Camellia sinensis. Rats in experimental clusters by mouth fed with C. sinensis at 250 mg/kg or 500 mg/kg daily for 2 months. After 60 days, all rats were sacrificed. Blood specimens were gathered for liver biochemical examination. Livers of all groups were dissected out and subjected to histopathological examination through the Hematoxylin and Eosin stain, Masson trichrome, and immunohistochemistry stains (PCNA). Liver tissue homogenate was also analyzed for antioxidant activity parameters.

RESULTS

Gross morphological examination showed a regular liver architecture in C. sinensis fed collections compared to the TAA sets. Histology of rat's liver fed with C. sinensis showed an important decrease in the liver index with hepatic cells propagation, mild cellular injury, and immunostaining showed significant down-expression of proliferating cell nuclear antigen (PCNA). TAA produced liver fibrosis through a significant increase in serum alanine transferase, aspartate aminotransferase, alkaline phosphatase, and bilirubin. Total protein and albumin also decreased in the TAA group. Moreover, the reduction of antioxidant enzyme activity including superoxide dismutase and catalase as well as the increase in malondialdehyde was detected in the TAA control group. Meanwhile, an abnormal level of liver biochemical parameters was restored closer to the normal levels in serum of the C. sinensis-fed clusters. In addition, C. sinensis fed assemblies showed elevated antioxidative enzymes activity with a reduction in malondialdehyde level comparable to the levels in silymarin-treated rats.

CONCLUSIONS

Green tea potentially inhibited the progression of liver cirrhosis, down -regulation of PCNA proliferation, prevented oxidation of hepatocytes, recovered SOD and CAT enzymes, condensed MDA and reduced cellular inflammation.

Capillary electrophoresis-UV analysis using silica-layer coated capillary for separation of seven phenolic acids and caffeine and its application to tea analysis

Abstract

This work presents an innovative silica-layer coated capillary with comparison study of the silica-layer coated capillary and the fused-silica capillary for the separation of seven phenolic acids viz. p-hydroxyphenylacetic acid (PHPA), p-coumaric acid (PCA), p-hydroxybenzoic acid (PHBA), caffeic acid (CFA), (3,4-dihydroxyphenyl)acetic acid (DHPA), gallic acid (GLA), and 2,3,4-trihydroxybenzoic acid (THBA), together with caffeine (CF), by capillary electro-chromatography (CEC) and micellar electrokinetic chromatography (MEKC), respectively. The running buffer was 25.0 mM borate at pH 9.0, with addition of 50.0 mM sodium dodecyl sulfate for the MEKC mode. The non-coated capillary could not separate all seven phenolic acids by CEC or MEKC. This was achieved using the coated capillary for both CEC and MEKC. The innovative coated capillary with CEC had plate number N ≥ 2.0 × 104 m−1 and resolution Rs ≥ 1.6 for all adjacent pairs of peaks. The capillary was also able to separate GLA and THBA which are structural isomers. Although MEKC mode provided comparable efficiency and selectivity, the reduced EOF of the coated capillary led to longer separation time. The linear calibration range of the seven phenolic acids and caffeine were different but the coefficients of determinations (r2) were all > 0.9965. The precisions of the relative migration times and peak area ratios of analyte to internal standard were 0.1–1.8% and 1.8–6.8%, respectively. There were no statistical differences in the efficiency of separation of the phenolic acids and caffeine for three coated capillaries. It was applied to the analysis of caffeine and phenolic acids in brewed tea using tyramine as the internal standard. The tea samples were diluted prior to analysis by CEC. The separation was less than 15 min. Caffeine, gallic acid and p-coumaric acid were detected and quantified. Caffeine and gallic acid contents were 10.8–15.0 and 2.6–4.8 mg g−1 dry tea leaves, respectively. p-Coumaric acid was detected in only one of the samples with a content of 0.4 mg g−1. Percent recoveries of spiked diluted samples were 90 ± 9 to 106 ± 13%, respectively.

Article highlights

Graphical abstract

Campylobacter Biofilms: Potential of Natural Compounds to Disrupt Campylobacter jejuni Transmission

Microbial biofilms occur naturally in many environmental niches and can be a significant reservoir of infectious microbes in zoonotically transmitted diseases such as that caused by Campylobacter jejuni, the leading cause of acute human bacterial gastroenteritis world-wide. The greatest challenge in reducing the disease caused by this organism is reducing transmission of C. jejuni to humans from poultry via the food chain. Biofilms enhance the stress tolerance and antimicrobial resistance of the microorganisms they harbor and are considered to play a crucial role for Campylobacter spp. survival and transmission to humans. Unconventional approaches to control biofilms and to improve the efficacy of currently used antibiotics are urgently needed. This review summarizes the use plant- and microorganism-derived antimicrobial and antibiofilm compounds such as essential oils, antimicrobial peptides (AMPs), polyphenolic extracts, algae extracts, probiotic-derived factors, d-amino acids (DAs) and glycolipid biosurfactants with potential to control biofilms formed by Campylobacter, and the suggested mechanisms of their action. Further investigation and use of such natural compounds could improve preventative and remedial strategies aimed to limit the transmission of campylobacters and other human pathogens via the food chain.

Use of Green Tea Extract and Rosemary Extract in Naturally Cured Pork Sausages with White Kimchi Powder

The impact of green tea extract powder and rosemary extract powder, alone or in combination, on the quality characteristics of naturally cured pork sausages produced with white kimchi powder as a nitrate source was evaluated. Ground pork sausages were assigned to one of seven treatments: control (0.01% sodium nitrite and 0.05% sodium ascorbate), treatment 1 (0.3% white kimchi powder and 0.05% green tea extract powder), treatment 2 (0.3% white kimchi powder and 0.1% green tea extract powder), treatment 3 (0.3% white kimchi powder and 0.05% rosemary extract powder), treatment 4 (0.3% white kimchi powder and 0.1% rosemary extract powder), treatment 5 (0.3% white kimchi powder, 0.05% green tea extract powder, and 0.05% rosemary extract powder), and treatment 6 (0.3% celery juice powder, 0.05% green tea extract powder, and 0.05% rosemary extract powder). Naturally cured products had lower (p<0.05) cooking yield and residual nitrite content than control sausages. However, compared to the control, naturally cured products with white kimchi powder (treatments 1 to 5) showed similar the pH, oxidation-reduction potential, CIE L* values, CIE a* values, nitrosyl hemochrome content, total pigment content, and curing efficiency to the control. When the amount of green tea extract powder or rosemary extract powder was increased to 0.1% (treatments 2 and 4), lipid oxidation was reduced (p<0.05). These results indicate that green tea extract powder, rosemary extract powder, and white kimchi powder may provide an effective solution to replace synthetic nitrite and ascorbate used in traditionally cured products.

Green Synthesis, Characterization, and Evaluation of the Antimicrobial Activity of Camellia sinensis Silver Nanoparticles

An extremely worrying and alarming increase in the level of multiple drug resistance is reported in Sudan, in which bacterial strains are becoming resistant to many commonly available antibiotics. Eventually, it is becoming extremely difficult to treat debilitating infections. In search of promising solutions to this arising crisis, Camellia sinensis silver nanoparticles were synthesized using the green synthesis method. The synthesis of the Camellia sinensis silver nanoparticles is confirmed using analytical methods as ultraviolet-visible spectroscopy, X-ray diffractometer, and scanning electron microscopy. Using the ultraviolet-visible spectroscopy, an absorption band of 412 nm was observed. Furthermore, scanning electron microscopy revealed the presence of silver nanoparticles which fell within the range of 1–100 nm, and X-ray diffractometer analysis showed three intense peaks with a maximum intense peak at 24.3 theta. Nanoparticles distribution between 12 nm and 64 nm was observed with an average diameter of 18.115 nm. It also revealed orthorhombic-shaped nanoparticles. The synthesized nanoparticles showed antimicrobial activity against Staphylococcus aureus with a zone of inhibition of 7 mm, but none was detected against Escherichia coli. The obtained physicochemical properties were correlated with the antibacterial activity of the silver nanoparticles.

Configural learning memory can be transformed from intermediate-term to long-term in pond snail Lymnaea stagnalis

A lab bred W-strain of Lymnaea stagnalis exhibits configural learning (CL). CL is a form of higher order associative learning wherein when snails experience two contrasting stimuli together such as predatory odour (CE: crayfish effluent) and food odour (C: carrot odour) they learn and associate risk with food. The memory for CL has been shown to last 3 h. Here, we show that when only a single CL-training session is given only a 3 h memory is formed. Memory is not present 24 h after the training session. However, memory can be enhanced and snails show long term memory (24 h memory) when trained for a second time within a 7-day time period after the first CL-training. We further hypothesised that Green tea exposure will enhance memory persistence as catechins in green tea are shown to be cognitive enhancers. We thus subjected snails to CL training followed by green tea exposure which resulted in enhanced memory persistence and it occurred during memory consolidation phase. Thus, we show for the first time that CL intermediate-term memory can be transformed to long-term memory by green tea and multiple trainings in a lab bred strain of Lymnaea.

Kombucha Tea-A Double Power of Bioactive Compounds from Tea and Symbiotic Culture of Bacteria and Yeasts (SCOBY)

Kombucha is a low alcoholic beverage with high content of bioactive compounds derived from plant material (tea, juices, herb extracts) and metabolic activity of microorganisms (acetic acid bacteria, lactic acid bacteria and yeasts). Currently, it attracts an increasing number of consumers due to its health-promoting properties. This review focuses on aspects significantly affecting the bioactive compound content and biological activities of Kombucha tea. The literature review shows that the drink is characterized by a high content of bioactive compounds, strong antioxidant, and antimicrobial properties. Factors that substantially affect these activities are the tea type and its brewing parameters, the composition of the SCOBY, as well as the fermentation parameters. On the other hand, Kombucha fermentation is characterized by many unknowns, which result, inter alia, from different methods of tea extraction, diverse, often undefined compositions of microorganisms used in the fermentation, as well as the lack of clearly defined effects of microorganisms on bioactive compounds contained in tea, and therefore the health-promoting properties of the final product. The article indicates the shortcomings in the current research in the field of Kombucha, as well as future perspectives on improving the health-promoting activities of this fermented drink.

Therapeutic Properties of Edible Mushrooms and Herbal Teas in Gut Microbiota Modulation

Edible mushrooms are functional foods and valuable but less exploited sources of biologically active compounds. Herbal teas are a range of products widely used due to the therapeutic properties that have been demonstrated by traditional medicine and a supplement in conventional therapies. Their interaction with the human microbiota is an aspect that must be researched, the therapeutic properties depending on the interaction with the microbiota and the consequent fermentative activity. Modulation processes result from the activity of, for example, phenolic acids, which are a major component and which have already demonstrated activity in combating oxidative stress. The aim of this mini-review is to highlight the essential aspects of modulating the microbiota using edible mushrooms and herbal teas. Although the phenolic pattern is different for edible mushrooms and herbal teas, certain non-phenolic compounds (polysaccharides and/or caffeine) are important in alleviating chronic diseases. These specific functional compounds have modulatory properties against oxidative stress, demonstrating health-beneficial effects in vitro and/or In vivo. Moreover, recent advances in improving human health via gut microbiota are presented. Plant-derived miRNAs from mushrooms and herbal teas were highlighted as a potential strategy for new therapeutic effects.

Polysaccharides and polyphenol in dried Morinda citrifolia fruit tea after different processing conditions: Optimization analysis using response surface methodology

The increasing popularity of Morinda citrifolia has many medical and health benefits because of its rich polysaccharides (PSC) and polyphenols (PPN). It has become popular to brew the dry M. citrifolia fruit slice as tea in some regions of China. In this study, optimize the extraction parameters of M. citrifolia fruit tea polysaccharides and polyphenols using response surface methodology. The results indicated the highest PSC yield of 17% at 46 °C for 11 min and the ratio of water/M. citrifolia fruit powder was 78 mL/g. The optimum extraction of PPN was at 95 °C for 10 min and the ratio of water/M. citrifolia fruit powder 90 mL/g, with 8.93% yield. Using dry M. citrifolia fruit slices as a tea is reported for the first time. Based on the results, the maximum level of PSC can be obtained under condition by infusing about four dried M. citrifolia fruit slice with average thickness and size in warm boiled water for 11 min, taking a 300 mL cup (300 mL of water) for example. The maximum level of PPN can be obtained by adding three slices of dried M. citrifolia fruit slice to boiled water for 10 min. Considering the powder used in our study, the further pulverization of cutting into powder is more conducive to material precipitation. This study provides a scientific basis for obtaining PSC and PPN from dry M. citrifolia fruit slice tea by brewing.

Green and white teas as health-promoting foods

Tea is one of the most consumed beverages around the world and as such, it is constantly the object of novel research. This review focuses on the research performed during the last five years to provide an updated view of the current position of tea regarding human health. According to most authors, tea health benefits can be traced back to its bioactive components, mostly phenolic compounds. Among them, catechins are the most abundant. Tea has an important antioxidant capacity and anti-inflammatory properties, which make this beverage (or its extracts) a potential aid in the fight against several chronic diseases. On the other hand, some studies report the possibility of toxic effects and it is advisable to reduce tea consumption, such as in the last trimester of pregnancy. Additionally, new technologies are increasing researchers' possibilities to study the effect of tea on human gut microbiota and even against SARS CoV-2. This beverage favours some beneficial gut microbes, which could have important repercussions due to the influence of gut microbiota on human health.

Plant-derived antioxidants incorporated into active packaging intended for vegetables and fatty animal products: a review

Nowadays, the food industry is focused on improving the shelf life of products by controlling lipid oxidation using natural antioxidants. The study of natural antioxidants is a field that attracts great interest because of their greater safety compared to synthetic ones. Plant-derived antioxidants being eco-friendly and effective are increasingly playing an important role in food preservation. When incorporated into active packaging, plant-derived antioxidants have no direct contact with foods, and will not change the colour or taste of the foods. They will, however, inhibit the development of rancidity, retard formation of toxic oxidation products, maintain nutritional quality, and prolong the shelf life of products. This review summarises research on the development of plant-derived antioxidants in food packaging. Antioxidants are found in plants such as green tea, olive leaves, ginkgo leaves, rosemary, Indian gooseberry, cinnamon, savoury, bay leaves, mango leaves, sage and clove etc. Antioxidants can scavenge free radicals and inhibit the activity of polyphenol oxidase. Therefore, they can inhibit lipid oxidation and browning of fruit and vegetables. These active substances can be obtained through extracting the plants using solvents with different polarities. The oxidation resistance of active substances can be determined by DPPH radical scavenging capacity, oxygen radical absorbance capacity, PPO enzyme inhibition capacity and other methods. In recent years, research on the preparation of food packaging with plant-derived antioxidants has also made significant progress. One development is to encapsulate plant-derived antioxidants such as tea polyphenols with capsules containing inorganic components. Thus, they can be blended with polyethylene granules and processed into active packaging film by industrial production methods such as melting, extrusion and blowing film. This research promotes the commercial application of active packaging incorporated with plant-derived antioxidants.

Antimicrobial Polyamide-Alginate Casing Incorporated with Nisin and ε-Polylysine Nanoparticles Combined with Plant Extract for Inactivation of Selected Bacteria in Nitrite-Free Frankfurter-Type Sausage

The effects of combining a polyamide-alginate casing incorporated with nisin (100 ppm and 200 ppm) and ε-polylysine (500 ppm and 1000 ppm) nanoparticles and a mixed plant extract as ingredient in sausage formulation (500 ppm; composed of olive leaves (OLE), green tea (GTE) and stinging nettle extracts (SNE) in equal rates) were studied to improve the shelf life and safety of frankfurter-type sausage. The film characteristics and microbiological properties of sausage samples were evaluated. Sausage samples were packaged in polyethylene bags (vacuum condition) and analysed during 45 days of storage at 4 °C. Control sausages were also treated with 120 ppm sodium nitrite. Polyamide-alginate films containing 100 ppm nisin and 500 ε-PL nanoparticles had the highest ultimate tensile strength compared to other films. However, 100 ppm nisin and 500 ε-PL nanoparticles decreased water vapour permeability of films. The results also revealed that nisin nanoparticles had significantly (p < 0.05) low inhibitory effects against Escherichia coli, Staphylococcus aureus, molds and yeasts and total viable counts compared to control and ε-PL nanoparticles. Furthermore, 1000 ppm ε-PL nanoparticles displayed the highest antimicrobial activity. Based on the obtained results, the films containing ε-PL nanoparticle could be considered as a promising packaging for frankfurter-type sausages.

Catechins in green tea powder (matcha) are heat-stable scavengers of acrolein, a lipid peroxide-derived reactive carbonyl species

Lipid peroxidation-derived reactive carbonyl species (RCS) such as acrolein and 4-hydroxynonenal pose health risks. We characterized the RCS-scavenging reactions of tea catechins in an aqueous solution and in baked cake. Acrolein's reaction with each of the major tea catechins (epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate) resulted in the formation of mono-, di-, and tri-acrolein conjugates of each catechin as revealed by our LC-linear ion trap MS analysis. The formation of the acrolein-conjugates of the four catechins was confirmed in the reaction of acrolein with green tea powder (matcha) extract. The addition of matcha tea powder to cake dough significantly suppressed the accumulation of RCS during cake baking. The mono-acrolein conjugates of the four major catechins were detected in the baked cake. The RCS-scavenging capability of tea catechins offers a new functionality of matcha tea powder, and its heat stability demonstrates the usefulness of matcha as a food additive.

Optimum Additive Composition to Minimize Fat in Functional Goat Meat Nuggets: A Healthy Red Meat Functional Food

Optimally designed functional foods are considered the most important part of a balanced and healthy diet. Goat meat nuggets, an otherwise healthy option, are packed with undesirable saturated and unsaturated fats. The present work suggests an optimal functional formulation to reduce the surplus fat content of goat meat nuggets by adding two optimally calculated functional ingredients, namely, fenugreek leaves (FL) and psyllium husk (PH). Response surface optimization was performed to determine the optimal content of the functional ingredients (FL and PH), resulting in minimum fat content without affecting the overall acceptability (OA) and other properties representing the taste and texture (e.g., ash content, pH, crude fiber content, and moisture content) of the nuggets. Functional additives at optimum levels successfully reduced the fat content of the weight-conserved nuggets by almost 39% compared with the control nuggets. Minimal and acceptable effects were observed regarding OA and other properties representative of the taste and texture of the nuggets. An optimally designed, fat-attenuated goat meat nugget formulation is therefore prescribed, which complies with the nutritional standards of a balanced diet.