Dr. Gan is an Assistant Professor & Presidential Young Scholar at the Department of Food Science and Nutrition, Faculty of Science, The Hong Kong Polytechnic University (PolyU), HK SAR, China. He was previously a Principal Scientist at the Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), Singapore, and also an Adjunct Assistant Professor at the Department of Food Science & Technology, Faculty of Science, National University of Singapore (NUS). His main research interest focuses on R & D of food functional ingredients and probiotics with nutrition & health translational potential.
Kombucha is traditional drink made from the fermentation of a black tea infusion, and is believed... more Kombucha is traditional drink made from the fermentation of a black tea infusion, and is believed to offer a variety of health benefits. Recently, exploring kombucha made from alternative substrates has become a research hotspot. In this paper, two novel kombucha beverages were produced with bamboo leaf or mulberry leaf for the first time. Moreover, the effects of fermentation with leaf residues (infusion plus residues) or without leaf residues (only infusion) on the antioxidant properties of kombucha were compared. The ferric-reducing antioxidant power assay, Trolox equivalent antioxidant capacity assay, Folin–Ciocalteu method, and high-performance liquid chromatography were utilized to measure the antioxidant capacities, total phenolic contents, as well as some compound concentrations of the kombucha. The results showed that two types of kombucha had high antioxidant capacities. Moreover, kombucha fermented with bamboo leaf residues (infusion plus residues) significantly enhanced ...
Sprouts are recognized as nutritional and functional vegetables. In this study, 17 selected seeds... more Sprouts are recognized as nutritional and functional vegetables. In this study, 17 selected seeds were germinated simultaneously. The antioxidant capacity and total phenolic content (TPC) were determined for seeds and sprouts of all species. Both seed and sprout of white radish, with the highest antioxidant capacity, and TPC among all the 17 species, were further determined for phenolic metabolomics. Four phenolic classes with 316 phenolic metabolites were identified. 198 significantly different metabolites with 146 up-regulated and 52 down-regulated were confirmed, and high amounts of phenolic acids and flavonoids were found to be accumulated in the sprout. Several metabolism and biosynthesis, including phenylpropanoid, favone and flavonol, phenylalanine, and various secondary metabolites, were significantly activated. Significant correlations were found among FRAP, DPPH, ABTS, TPC, and phenolic profiles. Therefore, white radish sprout could be served as antioxidant and could be a ...
ObjectiveNigella sativa (N. sativa) from the family Ranunculaceae has medicinal properties. Previ... more ObjectiveNigella sativa (N. sativa) from the family Ranunculaceae has medicinal properties. Previous studies have reported promising findings showing that N. sativa may benefit cardiometabolic health; however, current evidence on its cardiometabolic effects on those with prediabetes and type 2 diabetes mellitus (T2DM) is still unclear. Hence, we conducted a systematic review and meta-analysis to assess the efficacy of N. sativa on cardiometabolic parameters in population with prediabetes and T2DM.MethodsPubMed/Medline, ISI Web of Science, Scopus, and Cochrane library were systematically searched up to June 20, 2022. Meta-analyses using random-effects models were used.ResultsEleven randomized controlled trials (RCTs) were included in the meta-analysis. N. sativa intervention resulted in significant changes in fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), c-reactive protein (CRP), and malondialdehyde (MDA), w...
Kombucha is a popular beverage with various bioactivities (such as antioxidant activity), which c... more Kombucha is a popular beverage with various bioactivities (such as antioxidant activity), which can be attributed to its abundant bioactive compounds, especially polyphenols. Kombucha is conventionally prepared by fermentation of a sugared black tea infusion without tea residue. In this study, the effects of black tea residue and green tea residue on kombucha were studied, and its antioxidant activities, total phenolic contents, as well as concentrations of polyphenols at different fermentation stages were evaluated using ferric-reducing antioxidant power, Trolox equivalent antioxidant capacity, Folin-Ciocalteu method and high-performance liquid chromatography with a photodiode array detector. The results showed that fermentation with tea residue could markedly increase antioxidant activities (maximum 3.25 times) as well as polyphenolic concentrations (5.68 times) of kombucha. In addition, green tea residue showed a stronger effect than black tea residue. Overall, it is interesting ...
Atanas G. Atanasov and Dongdong Wang acknowledge the support by the Polish KNOW (Leading National... more Atanas G. Atanasov and Dongdong Wang acknowledge the support by the Polish KNOW (Leading National Research Centre) Scientific Consortium “Healthy Animal - Safe Food,” decision of Ministry of Science and Higher Education No. 05-1/KNOW2/2015 and the European Union under the European Regional Development Fund (Homing/2017-4/41). Antoni Sureda was supported by the Institute of Health Carlos III (Project CIBEROBN CB12/03/30038).
Critical Reviews in Food Science and Nutrition, 2021
Tea, as a beverage, has been reputed for its health benefits and gained worldwide popularity. Tea... more Tea, as a beverage, has been reputed for its health benefits and gained worldwide popularity. Tea polyphenols, especially catechins, as the main bioactive compounds in tea, exhibit diverse health benefits and have wide applications in the food industry. The development of tea polyphenol-incorporated products is dependent on the extraction, purification, and identification of tea polyphenols. Recent years, many green and novel extraction, purification, and identification techniques have been developed for the preparation of tea polyphenols. This review, therefore, introduces the classification of tea and summarizes the main conventional and novel techniques for the extraction of polyphenols from various tea products. The advantages and disadvantages of these techniques are also intensively discussed and compared. In addition, the purification and identification techniques are summarized. It is hoped that this updated review can provide a research basis for the green and efficient extraction, purification, and identification of tea polyphenols, which can facilitate their utilization in the production of various functional food products and nutraceuticals.
Abstract Background Dark tea is a post-fermented tea with unique organoleptic characteristics. A ... more Abstract Background Dark tea is a post-fermented tea with unique organoleptic characteristics. A unique microbial fermentation procedure is involved in dark tea processing that is considered a major factor to manage the quality of dark tea. Dark tea is gaining increasing attention recently because it contains various bioactive compounds with diverse biological functions. Scope and approach This review summarizes the microbial fermentation process, main bioactive compounds, and important biological functions or health benefits of dark tea, emphasizing its protective effects against different diseases and relevant molecular mechanisms, and proposes the perspectives in research and application of dark tea. Key findings and conclusions Functional core microorganism-mediated bioconversion is crucial for the formation of dark tea's main quality components during the fermentation period. Dark tea contains a variety of bioactive compounds, including alkaloids, free amino acids, peptides, polyphenols, pigments, polysaccharides, and volatile compounds. Consumption of dark teas has been linked to multiple health benefits, such as antioxidant, anti-obesity, anti-diabetic, anti-cancer, cardiovascular protective, gastrointestinal protective, hepatoprotective, neuroprotective, and photoprotective activities. Future studies focusing on the health mechanisms of dark teas and the potential applications of dark tea in the food, pharmaceutical, and medical industries are guaranteed.
Although spice extracts are well known to exhibit antibacterial properties, there is lack of a co... more Although spice extracts are well known to exhibit antibacterial properties, there is lack of a comprehensive evaluation of the antibacterial effect of spices against antibiotic-resistant bacteria. In the present study, ethanolic extracts from a total of 67 spices were comprehensively investigated for their in vitro antibacterial activities by agar well diffusion against two common food-borne bacteria, Staphylococcus aureus and Salmonella enteritidis, with multi-drug resistance. Results showed that S. aureus was generally more sensitive to spice extracts than S. enteritidis. Of the 67 spice extracts, 38 exhibited antibacterial activity against drug-resistant S. aureus, while only four samples were effective on drug-resistant S. enteritidis. In addition, 11 spice extracts with inhibition zones greater than 15 mm were further verified for their broad-spectrum antibacterial properties using another 10 drug-resistant S. aureus strains. It was found that five spice extracts, including gal...
Ficus pumila L. has been used as a functional plant for a long time in East Asia, especially its ... more Ficus pumila L. has been used as a functional plant for a long time in East Asia, especially its fruits, as a dietary component in Japan and parts of China. A series of bioactive compounds, including phenolic acids, flavonoids, terpenoids, alcohols, and steroids, have been extracted from the stems, leaves, flowers, and fruits of Ficus pumila L. Accumulated studies have demonstrated that Ficus pumila L. has multiple therapeutic activities, including antioxidant, anti-inflammatory, antibacterial, antitumor, hypoglycemic, and cardiovascular protective effects. Moreover, Ficus pumila L. has extensive applications, such as in the food industry and ecological city construction. Herein, we summarize the latest knowledge about the bioactive compounds and therapeutic activities of Ficus pumila L., and its applications in the food industry and ecological city construction are also discussed. We hope that this comprehensive review can attract more attention to Ficus pumila L. and be helpful fo...
Douchi is a traditional salt-fermented soybean food with various bioactivities, such as anti-oxid... more Douchi is a traditional salt-fermented soybean food with various bioactivities, such as anti-oxidation, anti-diabetes, and anti-hypertension, which are greatly affected by the activities of protease and β-glucosidase during koji production. Edible mushroom by-products are ideal ingredients for enhancing food flavor and nutritional quality due to their unique nutritional characteristics of high protein, rich amino acids, and low calories. However, there is no research on the preparation of Douchi by the mixed fermentation of edible mushroom by-products and soybeans. In this study, response surface methodology (RSM) was used to optimize the fermentation conditions of edible mushroom by-product Douchi koji (EMDK) with protease and β-glucosidase activities as indicators, and the changes in the main bioactive compounds and antioxidant activities of unfermented raw samples (URS), Douchi koji without edible mushroom by-product (DKWE), and EMDK were compared. The results of single-factor te...
Kombucha is traditional drink made from the fermentation of a black tea infusion, and is believed... more Kombucha is traditional drink made from the fermentation of a black tea infusion, and is believed to offer a variety of health benefits. Recently, exploring kombucha made from alternative substrates has become a research hotspot. In this paper, two novel kombucha beverages were produced with bamboo leaf or mulberry leaf for the first time. Moreover, the effects of fermentation with leaf residues (infusion plus residues) or without leaf residues (only infusion) on the antioxidant properties of kombucha were compared. The ferric-reducing antioxidant power assay, Trolox equivalent antioxidant capacity assay, Folin–Ciocalteu method, and high-performance liquid chromatography were utilized to measure the antioxidant capacities, total phenolic contents, as well as some compound concentrations of the kombucha. The results showed that two types of kombucha had high antioxidant capacities. Moreover, kombucha fermented with bamboo leaf residues (infusion plus residues) significantly enhanced ...
Sprouts are recognized as nutritional and functional vegetables. In this study, 17 selected seeds... more Sprouts are recognized as nutritional and functional vegetables. In this study, 17 selected seeds were germinated simultaneously. The antioxidant capacity and total phenolic content (TPC) were determined for seeds and sprouts of all species. Both seed and sprout of white radish, with the highest antioxidant capacity, and TPC among all the 17 species, were further determined for phenolic metabolomics. Four phenolic classes with 316 phenolic metabolites were identified. 198 significantly different metabolites with 146 up-regulated and 52 down-regulated were confirmed, and high amounts of phenolic acids and flavonoids were found to be accumulated in the sprout. Several metabolism and biosynthesis, including phenylpropanoid, favone and flavonol, phenylalanine, and various secondary metabolites, were significantly activated. Significant correlations were found among FRAP, DPPH, ABTS, TPC, and phenolic profiles. Therefore, white radish sprout could be served as antioxidant and could be a ...
ObjectiveNigella sativa (N. sativa) from the family Ranunculaceae has medicinal properties. Previ... more ObjectiveNigella sativa (N. sativa) from the family Ranunculaceae has medicinal properties. Previous studies have reported promising findings showing that N. sativa may benefit cardiometabolic health; however, current evidence on its cardiometabolic effects on those with prediabetes and type 2 diabetes mellitus (T2DM) is still unclear. Hence, we conducted a systematic review and meta-analysis to assess the efficacy of N. sativa on cardiometabolic parameters in population with prediabetes and T2DM.MethodsPubMed/Medline, ISI Web of Science, Scopus, and Cochrane library were systematically searched up to June 20, 2022. Meta-analyses using random-effects models were used.ResultsEleven randomized controlled trials (RCTs) were included in the meta-analysis. N. sativa intervention resulted in significant changes in fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), c-reactive protein (CRP), and malondialdehyde (MDA), w...
Kombucha is a popular beverage with various bioactivities (such as antioxidant activity), which c... more Kombucha is a popular beverage with various bioactivities (such as antioxidant activity), which can be attributed to its abundant bioactive compounds, especially polyphenols. Kombucha is conventionally prepared by fermentation of a sugared black tea infusion without tea residue. In this study, the effects of black tea residue and green tea residue on kombucha were studied, and its antioxidant activities, total phenolic contents, as well as concentrations of polyphenols at different fermentation stages were evaluated using ferric-reducing antioxidant power, Trolox equivalent antioxidant capacity, Folin-Ciocalteu method and high-performance liquid chromatography with a photodiode array detector. The results showed that fermentation with tea residue could markedly increase antioxidant activities (maximum 3.25 times) as well as polyphenolic concentrations (5.68 times) of kombucha. In addition, green tea residue showed a stronger effect than black tea residue. Overall, it is interesting ...
Atanas G. Atanasov and Dongdong Wang acknowledge the support by the Polish KNOW (Leading National... more Atanas G. Atanasov and Dongdong Wang acknowledge the support by the Polish KNOW (Leading National Research Centre) Scientific Consortium “Healthy Animal - Safe Food,” decision of Ministry of Science and Higher Education No. 05-1/KNOW2/2015 and the European Union under the European Regional Development Fund (Homing/2017-4/41). Antoni Sureda was supported by the Institute of Health Carlos III (Project CIBEROBN CB12/03/30038).
Critical Reviews in Food Science and Nutrition, 2021
Tea, as a beverage, has been reputed for its health benefits and gained worldwide popularity. Tea... more Tea, as a beverage, has been reputed for its health benefits and gained worldwide popularity. Tea polyphenols, especially catechins, as the main bioactive compounds in tea, exhibit diverse health benefits and have wide applications in the food industry. The development of tea polyphenol-incorporated products is dependent on the extraction, purification, and identification of tea polyphenols. Recent years, many green and novel extraction, purification, and identification techniques have been developed for the preparation of tea polyphenols. This review, therefore, introduces the classification of tea and summarizes the main conventional and novel techniques for the extraction of polyphenols from various tea products. The advantages and disadvantages of these techniques are also intensively discussed and compared. In addition, the purification and identification techniques are summarized. It is hoped that this updated review can provide a research basis for the green and efficient extraction, purification, and identification of tea polyphenols, which can facilitate their utilization in the production of various functional food products and nutraceuticals.
Abstract Background Dark tea is a post-fermented tea with unique organoleptic characteristics. A ... more Abstract Background Dark tea is a post-fermented tea with unique organoleptic characteristics. A unique microbial fermentation procedure is involved in dark tea processing that is considered a major factor to manage the quality of dark tea. Dark tea is gaining increasing attention recently because it contains various bioactive compounds with diverse biological functions. Scope and approach This review summarizes the microbial fermentation process, main bioactive compounds, and important biological functions or health benefits of dark tea, emphasizing its protective effects against different diseases and relevant molecular mechanisms, and proposes the perspectives in research and application of dark tea. Key findings and conclusions Functional core microorganism-mediated bioconversion is crucial for the formation of dark tea's main quality components during the fermentation period. Dark tea contains a variety of bioactive compounds, including alkaloids, free amino acids, peptides, polyphenols, pigments, polysaccharides, and volatile compounds. Consumption of dark teas has been linked to multiple health benefits, such as antioxidant, anti-obesity, anti-diabetic, anti-cancer, cardiovascular protective, gastrointestinal protective, hepatoprotective, neuroprotective, and photoprotective activities. Future studies focusing on the health mechanisms of dark teas and the potential applications of dark tea in the food, pharmaceutical, and medical industries are guaranteed.
Although spice extracts are well known to exhibit antibacterial properties, there is lack of a co... more Although spice extracts are well known to exhibit antibacterial properties, there is lack of a comprehensive evaluation of the antibacterial effect of spices against antibiotic-resistant bacteria. In the present study, ethanolic extracts from a total of 67 spices were comprehensively investigated for their in vitro antibacterial activities by agar well diffusion against two common food-borne bacteria, Staphylococcus aureus and Salmonella enteritidis, with multi-drug resistance. Results showed that S. aureus was generally more sensitive to spice extracts than S. enteritidis. Of the 67 spice extracts, 38 exhibited antibacterial activity against drug-resistant S. aureus, while only four samples were effective on drug-resistant S. enteritidis. In addition, 11 spice extracts with inhibition zones greater than 15 mm were further verified for their broad-spectrum antibacterial properties using another 10 drug-resistant S. aureus strains. It was found that five spice extracts, including gal...
Ficus pumila L. has been used as a functional plant for a long time in East Asia, especially its ... more Ficus pumila L. has been used as a functional plant for a long time in East Asia, especially its fruits, as a dietary component in Japan and parts of China. A series of bioactive compounds, including phenolic acids, flavonoids, terpenoids, alcohols, and steroids, have been extracted from the stems, leaves, flowers, and fruits of Ficus pumila L. Accumulated studies have demonstrated that Ficus pumila L. has multiple therapeutic activities, including antioxidant, anti-inflammatory, antibacterial, antitumor, hypoglycemic, and cardiovascular protective effects. Moreover, Ficus pumila L. has extensive applications, such as in the food industry and ecological city construction. Herein, we summarize the latest knowledge about the bioactive compounds and therapeutic activities of Ficus pumila L., and its applications in the food industry and ecological city construction are also discussed. We hope that this comprehensive review can attract more attention to Ficus pumila L. and be helpful fo...
Douchi is a traditional salt-fermented soybean food with various bioactivities, such as anti-oxid... more Douchi is a traditional salt-fermented soybean food with various bioactivities, such as anti-oxidation, anti-diabetes, and anti-hypertension, which are greatly affected by the activities of protease and β-glucosidase during koji production. Edible mushroom by-products are ideal ingredients for enhancing food flavor and nutritional quality due to their unique nutritional characteristics of high protein, rich amino acids, and low calories. However, there is no research on the preparation of Douchi by the mixed fermentation of edible mushroom by-products and soybeans. In this study, response surface methodology (RSM) was used to optimize the fermentation conditions of edible mushroom by-product Douchi koji (EMDK) with protease and β-glucosidase activities as indicators, and the changes in the main bioactive compounds and antioxidant activities of unfermented raw samples (URS), Douchi koji without edible mushroom by-product (DKWE), and EMDK were compared. The results of single-factor te...
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