JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 139
·期 15
·51928
·
IF 3.125
Xietian Yu,Li Lin,Liping Mei,Chengyi Sun,Zhijie Zhu,Xianfeng Du,Peirong Chen
Corn starch/polyvinyl alcohol (PVA) composite films containing different concentrations of tea polyphenols (TP) were fabricated by casting. Scanning electron microscopy and atomic force microscopy images showed that when the TP content was less than 8%, the films were relatively uniform, but with increasing TP concentration, the films became rougher and uneven. Fourier transform infrared, 13 C nuclear magnetic resonance, and X-ray diffraction techniques were used to investigate the interactions between TP, starch, and PVA. The incorporation of TP deepened the color and increased the opacity and solubility of the films. The tensile strength and elongation at break first increased and then decreased with increasing TP content. Furthermore, the addition of TP increased the antioxidant activity of the films, specifically, their ability to scavenge 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azinobis (3-ethylberizothiazoline-6-sulfonic acid). The addition of TP can effectively enhance the performance of starch composite films and their potential for application in antioxidant food packaging.
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APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2021
·Vol. 193
·期 10
·3062-3078
·
IF 2.926
Wei Yanli,Chen Xi,Yang Ting,Wan Junfen,Cao Xuejun
Aqueous two-phase systems (ATPS) have the advantages of environmentally friendly, high mass transfer efficiency, and mild extraction conditions. However, it is difficult to recycle these polymers, which limits the large-scale application of ATPS. In this study, a novel recyclable ATPS was constructed with thermo-responsive polymer P N and pH-responsive polymer P ADB4.78 for the partition of tea saponin. P N represents poly-( N -isopropylacrylamide), and P ADB4.78 represents poly-(acrylic acid-dimethylamine ethyl methacrylate-butyl methacrylate), where 4.78 in the subscript indicate the isoelectric point of the polymer. The recoveries of P N and P ADB4.78 were 95.36% and 93.48%, respectively, after two cycles. Meanwhile, the phase formation mechanism of ATPS was studied by surface tension and low-field nuclear magnetic resonance (LF-NMR). The effects of polymer concentration, pH, temperature, types and concentrations of salt were investigated on tea saponin partition. In the 1.5% (w/v) P N /3.5% (w/v) P ADB4.78 ATPS, the optimal partition coefficient ( K ) of crude tea saponin were 0.15 in the presence of 1.5 mM KCl at pH 7.6 and 25 °C while the extraction recovery (ER b ) reached 92.13%. The K and ER b of tea saponin from tea seeds were 0.12 and 94.50% with 7.5 mM LiBr at pH 8.0 and 25 °C, respectively.
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FOOD CHEMISTRY
·
2021
·
IF 7.514
Qing-Qing Cao,Fang Wang,Jie-Qiong Wang,Jian-Xin Chen,Jun-Feng Yin,Lijun Li,Fan-Ke Meng,Yong Cheng,Yong-Quan Xu
The effects of brewing water on the sensory attributes and physicochemical properties of tea infusions made from Chinese teas were investigated. The tea infusions brewed in water with higher pH and total dissolved solids (TDS), generally had a darker color and lower overall sensory acceptability. Moreover, those infusions had less catechins, particularly galloylated-catechins, and lower antioxidant capacity. The teas with less fermentation contained more galloylated-catechins and had higher antioxidant capacity, but were much more susceptible to high mineral brewing water. Green tea was proved to be the most susceptible one, whereas dark tea the most stable one. Green tea infusions prepared with higher pH/TDS water were more rapidly oxidized, resulting in a darker color due to polymerization of catechins, when exposed to the air. These findings suggested that low mineral brewing water was better for Chinese tea, both from the sensory and health benefit perspectives.
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JOURNAL OF FOOD SCIENCE
·
2020
·Vol. 85
·期 11
·3786-3796
·
IF 2.479
Hao-Xiang Gao,Jie Yu,Nan Chen,Wei-Cai Zeng
The effects and action mechanism of tea polyphenols (TP) on the quality of rapeseed oil during frying process were investigated. Results showed that compared with control, TP (0.04%, w / w ) exhibited the remarkable ability to inhibit the deterioration of acid value, peroxide value, anisidine value, viscosity, and color of frying oil. By using gas chromatography-mass spectrometry, frying oil with TP showed the higher content of unsaturated fatty acids (72.79%) and lower content of trans fatty acids (3.36%) than those of control. Meanwhile, frying oil with TP had a higher total phenolic content than control at the same frying time. In addition, the thermo gravimetric-differential scanning calorimetry results showed that TP could increase the oxidation stability of rapeseed oil. Furthermore, according to the Fourier transform infrared and molecular dynamic simulation results, TP could reduce the breaking degree of = C–H bond, C–O–C bond, and C = C bond in oil molecules, and inhibit the oxidation of oil components by inhibiting the generation of free radicals and eliminating free radicals. All present results suggested that TP showed the potential value to be used for protecting the quality of oil during the frying process in food and chemical industries. Practical Applications The inhibitory effect of tea polyphenols on the deterioration of quality of rapeseed oil during frying was found and the mechanism had also preliminarily interpretation. This work provided a method for monitoring the quality of fry oil and provided the theoretical basis for the use of tea polyphenols in frying.
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ENVIRONMENTAL TECHNOLOGY
·
2020
·
IF 2.213
Xiaolin Li,Yongxing Zhan,Lianghu Su,Yudong Chen,Mei Chen,Longjiang Zhang,Guangyin Zhen,Zhihua Han,Xiaoli Chai
Dark tea-iron nanoparticles (DT-Fe NPs) were prepared using extracts of dark tea leaves as a reducing agent, and further underwent thermal treatment in air. The H2S removal performances of thermal-treated DT-Fe NPs for biogas were further evaluated using a custom-designed fixed-bed reactor (reaction temperature of 250°C, H2S content of 1%). Significant morphology and chemical composition differences were observed when DT-Fe NPs were treated at different temperatures (300–800oC). X-ray diffractometer analysis revealed that a phase transition from γ-Fe2O3 to α-Fe2O3 occurred under heat treatment. When the thermal treatment temperature was 300°C, only α-Fe2O3 was detected. Both α-Fe2O3 and γ-Fe2O3 were present in the sample treated at 400°C. When the thermal treatment temperature was 500–800°C, γ-Fe2O3 in the sample was completely converted to α-Fe2O3. The H2S removal capacity is 14.72 mg H2S/g for DT-Fe NPs without treatment. However, the value increased significantly to 408.30 mg H2S/g after 400°C thermal treatment, which can be explained by the formation of highly active γ-Fe2O3. The reaction product of thermal-treated DT-Fe NPs at 400°C and H2S were further characterized by X-ray diffractometer and X-ray photoelectron spectroscopy. The results showed that it is composed of FeS2 and FeS, in which 72.6% of the sulphur existed as disulphide and 27.4% as monosulphide.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2020
·
IF 4.192
Xiaoyun Jiang,Dingmin Zhang,Yongling Lu,Lishuang Lv
Increasing evidence has identified the unsaturated aldehyde acrolein (ACR) as the potential factor that causes deoxyribonucleic acid cross-linking and the development of chronic diseases. The objective of this study was to investigate the mechanism by which theophylline (TP) scavenges ACR for the first time. TP efficiently scavenged ACR through forming adducts, which was demonstrated in a system in which TP was incubated with ACR at different ratios for different times for liquid chromatography with tandem mass spectrometry. Then, the mono- and di-ACR-TP adducts were purified, and their structures were elucidated by high-resolution mass spectrometry and nuclear magnetic resonance analysis. We found that the ACR residue on mono-ACR-TP further trapped one more ACR and formed di-ACR-TP adducts. Furthermore, mono- and di-ACR-TP had similar time-dependent ACR-scavenging activity to TP. Finally, we demonstrated that green tea, coffee, and cocoa inhibited ACR by trapping ACR to form mono- and di-ACR-TP adducts during the incubation of green tea, coffee, and cocoa with ACR.
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Journal of Food Measurement and Characterization
·
2020
·Vol. 14
·期 4
·2134-2144
·
IF 1.648
Huang Xin,Wang Li,Chen Jingyu,Jiang Chengyu,Wu Shijia,Wang Hongxin
Tea polyphenols (TPPs), as the most important functional component in tea extract, are easily contaminated by many heavy metals during tea processing, transportation and storage. TPPs with heavy metals can cause serious health problems and economic losses. In this study, to efficiently remove heavy metals from TPPs without affecting their active compounds and antioxidant functions, we prepared the amino-functionalized modified silica gel (AFSG) to remove Pb, Cu and Cd from TPPs, and determined removal rate of heavy metals, total polyphenolic content (TPC) and antioxidant activity of TPPs before and after adsorption. The static adsorption experiments showed that the adsorption isotherms were consistent with Langmuir model, in which the maximum sorption capacities of Pb, Cu and Cd were 140.23, 100.75 and 48.03 mg/g (25 °C, pH 5.0), respectively. Compared with before adsorption, the contents of Pb, Cu and Cd in 3 TPPs samples decreased significantly after adsorption on AFSG column (p < 0.01). However, the TPC and antioxidant capacity of the 3 TPPs samples had no significant effect before and after adsorption (p > 0.05). Meanwhile, the desorption and regeneration experiment showed that after 6 times of cyclic adsorption, the removal ability of Pb, Cu and Cd in TPPs by AFSG column could still reach 98.1%, 99.59% and 99.78%, respectively. Therefore, these results suggested that AFSG column could effectively remove heavy metals from TPPs without affecting the TPC and its antioxidant activity, it has potential applications in the removal and detection of heavy metals in TPPs.
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Foods
·
2023
·Vol. 12
·期 19
·3702
·
IF 5.2
Qincao Chen,Penghui Yu,Ziyi Li,Yuhang Wang,Yafang Liu,Yin Zhu,Haihui Fu
Aroma is a vital factor influencing tea quality and value. It is a challenge to produce a kind of black tea with a floral/fruity aroma, good taste, and without a green/grassy odor simultaneously using small- and medium-leaf tea species. In this study, the effect of re-rolling treatment on the aroma quality of small-leaf Congou black tea was investigated using the methods of the equivalent quantification of aroma and gas chromatography–mass spectrometry (GC-MS). Sensory evaluation showed that re-rolling treatment improved the aroma quality of Congou black tea by conferring upon it floral and fruity scents. In total, 179 volatile compounds were identified using GC-MS, of which 97 volatiles showed statistical differences (Tukey s-b(K),p< 0.05). Re-rolling treatment significantly reduced the levels of alcoholic fatty acid-derived volatiles (FADVs) and volatile terpenoid (VTs), but increased the levels of aldehydic and ester FADVs, most amino acid-derived volatiles (AADVs), carotenoid-derived volatiles (CDVs), alkene VTs, and some other important volatile compounds. Based on the odor characteristics and fold changes of differential volatile compounds, hexanoic acid, hexyl formate, cis-3-hexenyl hexanoate, (Z)-3-hexenyl benzoate, hexyl hexanoate, phenylacetaldehyde, benzyl alcohol, β-ionone, α-ionone, dihydroactinidiolide, ipsenone, β-farnesene, β-octalactone, melonal, etc., were considered as the potential key odorants responsible for the floral and fruity scents of re-rolled black tea. In summary, this study provides a novel and simple processing technology to improve the aroma quality of small-leaf Congou black tea, and the results are beneficial to enriching tea aroma chemistry.Keywords:black tea;aroma;re-rolling;GC-MS;fermentation
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Foods
·
2023
·Vol. 12
·期 18
·3420
·
IF 5.2
Minyu Cai,Liyan Huang,Sashuang Dong,Nanxin Diao,Weilian Ye,Zhiye Peng,Xiang Fang
Summer green tea (SGT) has a low cost and high annual yield, but its utilization rate is limited due to suboptimal quality. The aim of this study is to enhance the flavor of SGT using fermentation withA. nigerRAF106 while examining changes in its metabolites during this process. The results revealed an elevation in the content of alcohol, alkanes, and nitroxides in tea leaves following the process of fermentation. The predominant volatile compounds identified in tea leaves after undergoing a 6-day fermentation period were linalool, (Z)-α, α, 5-trimethyl-5-vinyltetrahydrofuran-2-methanol, (E)-linalool oxide (furan type), linalool oxide (pyran type), and theapyrrole. These compounds exhibited significant increases of 31.48%, 230.43%, 225.12%, 70.71%, and 521.62%, respectively, compared to the non-fermented control group (CK). The content of non-ester catechins, soluble sugars, and total flavonoids reached their peak on the 4th day of fermentation, exhibiting significant increases of 114.8%, 95.59%, and 54.70%, respectively. The content of gallic acid and free amino acids reached their peak on the 6th day of fermentation, exhibiting significant increases of 3775% and 18.18%, respectively. However, the content of ester catechin decreased by 81.23%, while caffeine decreased by 7.46%. The content of lactic acid, acetic acid, and citric acid in tea after fermentation was 421.03%, 203.13%, and 544.39% higher than before fermentation, respectively. The present study offers a fresh approach for the advancement of SGT.Keywords:summer green tea;Aspergillus niger;fermentation;flavor
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FOOD CHEMISTRY
·
2023
·
IF 8.8
Xiaohui Wang,Jingjie Cao,Xin Cheng,Xuyang Liu,Wenfeng Zhu,Yan Li,Xiaochun Wan,Shengkeng Chen,Linlin Liu
Solar withering is essential for the aroma formation of oolong tea, but due to the rainy and humid weather in plantation areas, solar withering became insufficient which seriously limits high-grade oolong tea production. This study aims to investigate ultraviolet B (UV-B) effects on the aroma characteristics of oolong tea and its feasibility in improving tea aroma quality. Sensory evaluation, odorant quantitation, and aroma characteristic analysis suggested UV-B application during the aeration process provided similar effects as solar withering in improving the aroma quality of oolong tea. UV-B application significantly increased fruity and floral odorants (4-hexanolide, α -farnesene, and β -ocimene by 44%, 74%, and 37%, respectively), and decreased green and fatty odorants (hexanal, ( E )-2-octenal, and ( Z )-4-heptenal by 42%, 45%, and 27%, respectively). These indicate UV-B is crucial for the flowery and fruity aroma formation of oolong tea, which can be potentially applied to oolong tea production, especially under unsunny weather.
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FOOD CHEMISTRY
·
2023
·
IF 8.8
Yanyan Cao,Chuangsheng Huang,Yating Guo,Yingxin Xu,Shuying Gong,Qiang Chu,Ping Chen
Longjing tea is renowned for its fresh aroma and high value. However, during storage, the emergence of an off-flavor known as “stale odor” can significantly impact the flavor quality and economic benefits of Longjing tea. Yet, the specific volatiles responsible for this stale odor in Longjing tea remain unknown. In this study, Longjing tea samples with varying degrees of stale odor intensity were analyzed using simultaneous distillation extraction coupled with gas chromatography-mass spectrometry (SDE-GC–MS). Through odor activity value (OAV) and fractional omission testing, hexanoic acid and trans -2-nonenal were identified as the primary contributors to the stale odor. Moreover, the concentration of hexanoic acid was found to be valuable in predicting the intensity of the stale odor in Longjing tea. The oxidative degradation of linoleic acid was proved as the generation pathway of stale odor in Longjing tea. These findings provide essential theoretical principles for Longjing tea production and preservation.
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Food Chemistry-X
·
2023
·
IF 6.1
Dan Chen,Ao Wang,Jialiang Lv,Chao Tang,Chang-hai Jin,Jun Liu,Xiaoxiong Zeng,Li Wang
Tea ( Camellia sinensis L.) flower polysaccharides (TFPS) have various health-promoting functions. In the present work, the structure of a purified TFPS fraction, namely TFPS-1-3p, and its in vitro digestive properties were investigated. The results demonstrated that TFPS-1-3p was a typical heteropolysaccharide consisting of rhamnose (Rha), arabinose (Ara), galactose (Gal) and galacturonic acid (GalA) with a molecular weight of 47.77 kDa. The backbone of TFPS-1-3p contained → 4)-α- d -Gal p A(-6-OMe)-(1 → 4)-α-Gal p A-(1 → and → 4)-α- d -Gal p A(-6-OMe)-(1 → 2,4)-α- l -Rha p -(1 → linkages. The branch linkages in TFPS-1-3p contained → 6)-β- d -Gal p -(1→, →3,6)-β- d -Gal p -(1→, →5)-α- l -Ara f -(1 → and → 3,5)-α- l -Ara f -(1 →. Subsequently, TFPS-1-3p could not be degraded under simulated human gastrointestinal conditions but could be of use to human fecal microbes, thereby lowering the pH and increasing the production of short-chain fatty acids (SCFAs) of the gut microenvironment and altering the composition of the gut microbiota. The relative abundance of Fusobacterium_mortiferum Megasphaera_elsdenii_DSM_20460, Bacteroides thetaiotaomicron , Bacteroides plebeius and Collinsella aerofaciens increased significantly, potentially contributing to the degradation of TFPS-1-3p.
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