红茶、绿茶提取物联合应用的护肤功效研究

以红茶提取物、绿茶提取物为考察对象,考察了红茶提取物和绿茶提取物的单独及联合应用的防晒、保湿、抗氧化、美白、抗衰老等功能,测试了二者在以上功能联合应用是否具有协同增效作用。结果表明,红茶、绿茶提取物在保湿、抗氧化、美白、抗衰老等功能上,联合应用比二者单独应用效果更强,其中2 g/L红、绿茶提取物混合物在抑制酪氨酸酶、弹性蛋白酶方面的联合指数CI仅为0.29和0.054,协同增效效果显著。     

Antioxidant activity of green teas in different lipid systems

Different commercial green teas from Japan, China, and India, were compared in different lipid systems. Green teas were active antioxidants in bulk corn oil oxidized at 50°C but were prooxidant in the corresponding oil-in-water emulsions. Green teas also were active antioxidants in soybean lecithin liposomes oxidized at 37°C in the presence of cupric acetate as catalyst. At 50°C, however, three of the samples of green tea were active antioxidants in the absence of copper catalyst, and two samples showed prooxidant activity in the presence of copper catalyst. The marked variation in activity among green tea samples may be due partly to differences in their relative partition between phases in different lipid systems. The improved antioxidant activity observed for green teas in lecithin liposomes compared to corn oil emulsions can be explained by the greater affinity of the polar tea catechin gallates for the polar surface of the lecithin bilayers, thus affording better protection against oxidation. Liposomes may thus be appropriate lipid models to evaluate antioxidants for foods containing phospholipids.     

Total phenolic contents and antioxidant capacities of herbal and tea infusions

In order to supply new information on the antioxidant function of selected beverages for nutritionists and the general public, total phenolic contents of 51 kinds of herbal and tea infusions made in China were measured by the Folin-Ciocalteu method, and their antioxidant capacities were evaluated using ferric reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays. A significant correlation between FRAP and TEAC values suggested that antioxidant components in these beverages were capable of reducing oxidants and scavenging free radicals. The high correlation between antioxidant capacities and total phenolic contents indicated that phenolic compounds could be one of the main components responsible for antioxidant activities of these beverages. Generally, these beverages had high antioxidant capacities and total phenolic contents, and could be important dietary sources of antioxidant phenolics for prevention of diseases caused by oxidative stress.     

Stabilization of seal blubber and menhaden oils with green tea catechins

Catechins, namely (−)epicatechin (EC), (−)epigallocatechin (EGC), (−)epicatechin gallate (ECG) and (−)epigallocatechin gallate (EGCG), were isolated from commercial Chinese green leaves. The antioxidant activity of isolated catechins was compared with those of α-tocopherol, butylated hydroxyanisole (BHA), butylated hydroxytolene (BHT) andtert-butylhydroquinone (TBHQ), all at 200 ppm, in refined, bleached and deodorized seal blubber oil and menhaden oil. The study was carried out under Schaal oven test conditions at 65°C over a 144-h period, except for weight gain measurements, which were continued for up to 200 h. Progression of oxidation was monitored by measuring changes in weight gain and values of peroxide, conjugated diene, and 2-thiobarbituric acid-reactive substances. Oils treated with tea catechins showed excellent oxidative stability as compared with samples that contained commonly used antioxidants, such as α-tocopherol, BHA, BHT, and TBHQ. The potency of catechins in prevention of oxidation of marine oils was in the decreasing order of ECG> EGCG> EGC> EC; ECG was slightly more effective than TBHQ in systems studied.     

The Effects of Infrared Roasting on HCN Content,Chemical Composition and Storage Stability of Flaxseed and Flaxseed Oil

Flaxseeds were roasted at 1150 W/m² radiation intensity with short and medium wave infrared (IR) emitters for specific durations, which provided good visual and sensory quality. The effects of IR roasting on color properties, hydrogen cyanide (HCN) content, tocopherols and fatty acid composition of the flaxseed and flaxseed oil were investigated. Further, flaxseeds were stored for 6 months and free fatty acid content and peroxide values were followed at 1-month intervals to understand the effect of IR treatment on hydrolytic and oxidative stability. HCN content of the flaxseeds was reduced up to 59% with IR roasting. Tocopherol content of the IR roasted flaxseed oil was higher than that of the control. No notable variation was observed in fatty acid composition with regard to IR treatment. Free fatty acid content of IR roasted flaxseeds did not increase during storage, while peroxide value of the seeds significantly increased up to 95 mEq O₂/kg oil.     

Role of Flaxseed Meal Feeding for Different Durations in the Lipid Deposition and Meat Quality in Broiler Chickens

This study investigated the role of flaxseed meal (FSM), a rich terrestrial source of ω-3 fatty acids, in the alteration of the fatty acid profile and metabolism, health indices, physicochemical properties, and sensory quality of broiler chicken meat. The broiler chickens were fed 100 g FSM kg⁻¹ diet for different time periods (1, 2, 3, 4, and 5 weeks). The results revealed that 100 g FSM feeding in broiler chickens for at least 3 weeks increased (P < 0.01) the EPA, DHA, MUFA, PUFA, ω-3 PUFA, and ω-6 PUFA of broiler chicken meat with the corresponding decrease in palmitic acid, stearic acid, and SFA content. 100 g FSM feeding up to 3 weeks has increased the Δ⁹-desaturases (P < 0.05), thioesterase index (P < 0.01), and Δ⁵-desaturase + Δ⁶-desaturase activity (P < 0.01) along with an improvement in health indices (P < 0.01) of chicken meat. Similarly, a reduction in meat cholesterol and fat content of thigh meat (P < 0.01) was observed by feeding 100 g FSM for at least 3 weeks with no effect on the pH, color scores, and sensory evaluation of broiler chicken meat. The water-holding capacity (WHC) and extract release volume (ERV) decreased, whereas, drip loss of meat increased (P < 0.01) due to the feeding of 100 g FSM beyond 3 weeks. Thus, this study concluded that 100 g FSM feeding for 3 weeks in broiler chickens significantly improves the fatty acid profile, lipid metabolism, and health indices of meat, without compromising the physicochemical properties of broiler chicken meat.     

Serum β-carotene concentrations are associated with self-reported fatty acid intake in United States adults from the National Health and Examination Surveys

Bioavailability of dietary β-carotene (BC) is dependent on dose, quantity, dispersion, and presence of fat in the diet. Fats are comprised of a variety of fatty acids, which may impact the bioavailability of carotenoids. However, there is a gap in research on whether specific fatty acid classes affect serum BC concentrations in population samples. The primary objective of this study was to assess the association between reported fat and fatty acid intake and serum BC concentrations utilizing data from the National Health and Nutrition Examination Surveys (NHANES) 2003–2006. Data from 3278 NHANES participants 20–85 years old were analyzed to estimate the relationships between serum BC concentrations and reported saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acid intakes. Multiple linear regression estimated ln(serum BC) based on reported fatty acid intakes adjusted for age, sex, race/ethnicity, and reported dietary BC intakes. Mean and standard error (SE) for serum BC concentrations were 14.31 ± 0.05 μg/dl. Means and SE for total fat, SFA, MUFA, and PUFA were 85.7 ± 1.3, 26.9 ± 0.4, 31.1 ± 0.5, and 17.8 ± 0.4 g, respectively. There was a significant trend for association between serum BC and reported total fat intakes (r = −0.002, p < 0.0001), but the association was not strong. Multiple linear regression showed positive associations between serum BC concentrations and higher reported dietary PUFA consumption. PUFA alpha-linolenic acid intakes are positively associated with serum BC concentrations, while MUFA palmitoleic acid and SFA stearic acid were inversely associated with serum BC. The inverse association between MUFA and SFA suggests there may be multiple post-digestion factors affecting serum carotenoid concentrations.     

Antioxidant Efficacy of a New Synergistic,Multicomponent Formulation for Fish Oil Omega-3 Concentrates

Today, tocopherols serve as the industrial standard antioxidant protection for fish oil omega-3 concentrates. Synergistic interactions between tocopherols, ascorbyl palmitate and natural polyphenols extracted from plant sources have been demonstrated in model systems. The main goal for this work was to develop a mix of such antioxidants with improved efficacy in the context of preserving industrial marine oil concentrates. The antioxidant formulation comprises tocopherols, ascorbyl palmitate, rosemary extract and green tea catechins. Part of the scope was to develop a method for dissolving green tea catechins in oil. The key element of the method is to introduce green tea on a lipid insoluble carrier when dissolving the extract in the oil, and thereafter remove the carrier by filtration. The antioxidant mix was tested against tocopherol in omega-3 concentrates of minimum 300 mg/g eicosapentaenoic acid (EPA) plus 200 mg/g docosahexaenoic acid (DHA) in the form of triacylglycerides and ethyl esters. The mix was superior compared to tocopherols in suppressing both primary- and secondary oxidation. Weight increase measurements of oil in contact with air correlated well with standard oxidation tests within individual samples and the method was considered simple and useful for monitoring oxidation in omega-3 concentrates.     

Synthesis,characterization, and thermal behaviors of tannin stearates prepared from quebracho and pine bark extracts

Reported is the preparation of various condensed tannin stearates and the associated chemical characterization and thermal properties of these products. Stearate esters of condensed tannins from both quebracho and pine bark extracts were prepared in generally high, isolated yields from reaction with stearic acid chloride. Tannin esterification was confirmed by both Fourier transform infrared and nuclear magnetic resonance (NMR), and the average degree of stearate substitution was calculated from ¹H‐NMR analysis. Product degree of substitution (DS) was observed to proportionately increase with higher stearic acid chloride ratio with maximum DS values of 4.0 and 5.1 achieved for quebracho and pine tannins, respectively. Thermal analysis revealed that tannin stearate products have increased thermal stability with a degradation onset at significantly higher temperature for those samples possessing relatively greater DS. Analysis using differential scanning calorimetry revealed isolated products to consist of multiple components which exhibit interesting melt behaviors, a likely result from their work up on isolation. However, multiple melt features of the individual components in products were lost on heating to give single, broad melt endotherms due to coalescence of sample components. Furthermore, tannin stearate samples with high DS show relatively greater endothermic melting at higher temperature than those samples with lower DS. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thermal antioxidative kinetics of sesamol in triacylglycerols and fatty acid methyl esters of sesame,olive, and canola oils

Oxidation kinetics of the triacylglycerols (TAGs) and fatty acid methyl esters (FAMEs) of sesame, olive, and canola oils were studied in the presence of the different concentrations of sesamol (0.1%–0.16%) at 60, 80, and 100°C. Sesamol increased the temperature coefficient, T_C, and Q₁₀ number of the TAGs more significantly compared to the FAMEs. All the sesamol-added TAG and FAME systems, respectively, of the olive, canola, and sesame oils, respectively, exerted increased values of the Arrhenius (activation energy, E_a, and frequency factor, A) and Eyring (enthalpy, ΔH⁺⁺, and entropy, ΔS⁺⁺) equation parameters. Sesamol improved the Gibbs free energy (ΔG⁺⁺) of the activated complex formation in the canola, sesame, and olive systems, respectively, and the effect was greater in the FAMEs.     

Simple, high-efficiency synthesis of fatty acid methyl esters from soapstock

We report a simple method that efficiently esterifies the fatty acids in soapstock, an inexpensive, lipid-rich by-product of edible oil production. The process involves (i) alkaline hydrolysis of all lipid-linked fatty acid ester bonds and (ii) acid-catalyzed esterification of the resulting fatty acid sodium salts. Step (i) completely saponified all glycerides and phosphoglycerides in the soapstock. Following water removal, the resulting free fatty acid sodium salts were rapidly and quantitatively converted to fatty acid methyl esters (FAME) by incubation with methanol and sulfuric acid at 35°C and ambient pressure. Minimum molar reactant ratios for full esterification were fatty acids/methanol/sulfuric acid of 1∶30∶5. The esterification reaction was substantially complete within 10 min and was not inhibited by residual water contents up to ca. 10% in the saponified soapstock. The product FAME contained >99% fatty acid esters, 0% triglycerides, <0.05% diglycerides, <0.1% monoglycerides, and <0.8% free fatty acids. Free fatty acid levels were further reduced by washing with dilute sodium hydroxide. Free and total glycerol were <0.01 and <0.015%, respectively. The water content was <0.04%. These values meet the current specifications for biodiesel, a renewable substitute for petroleum-derived diesel fuel. The identities and proportions of fatty acid esters in the FAME reflected the fatty acid content of soybean lipids. Solids formed during the reaction contained 69.1% ash and 0.8% protein. Their sodium content indicated that sodium sulfate was the prime inorganic component. Carbohydrate was the predominant organic constituent of the solid.     

实现无机及分析化学实验绿色化的探索与实践

根据绿色化学使用化学药品的原则,就如何实现无机及分析化学实验的绿色化进行了初步的探索与实践。在无机及分析化学实验教学中,要让学生树立起绿色化学思想,加强和培养学生的绿色意识、环保意识。作者结合实际教学经验,指出改进实验方法,采用微型实验、小量-半微量实验,合理安排实验项目和次序,对实验产物进行回收利用是实现无机及分析化学实验绿色化的重要途径。     

Design of green zinc‐based thermal stabilizers derived from tung oil fatty acid and study of thermal stabilization for PVC

In this study, a new type of mixed calcium (Ca) and zinc (Zn) thermal stabilizers was prepared and evaluated for poly(vinyl chloride) (PVC) thermal stabilization. The mixed stabilizers were based on the Ca and Zn salts of polycarboxylic acid derived from eleostearic acid—the dominant fatty acid of tung oil fatty acids. Eleostearic acid was converted to a 21‐carbon diacid (C21DA) and a 22‐carbon triacid (C22TA), respectively, which were subsequently turned into calcium (Ca) and zinc (Zn) salts. Thermal stability of PVC compounds was examined by thermogravimetric analysis (TGA), discoloration test, Congo red test, and thermal decomposition kinetics. In comparison, commercial mixed Ca/Zn thermal stabilizers composed of stearate salts (CaSt₂/ZnSt₂), were employed as controls. Because the salts of C21DA, C22TA and stearate have different metal contents, thermal stabilization effects were compared on the basis of both equal salt weight and equal metal ion content. It was noted that under both cases the long‐term thermal stability of the PVC samples followed the order of C21DA‐Ca/C21DA‐Zn > C22TA‐Ca/C22TA‐Zn > CaSt₂/ZnSt₂. The results suggest that the mixed Ca/Zn salts based on tung oil‐derived polycarboxylic acids have higher metal ion contents and cycloaliphatic structures and can effectively improve the thermal stability of PVC. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44679.     

New green coatings made from fatty acid dispersions: improvement in barrier properties of biodegradable thermoplasticized-starch substrate

This work was aimed at developing new coatings on biodegradable substrates for possible use in food packaging. In order to study barrier properties of these coatings made from fatty acid dispersions, oxygen permeability, water vapor permeability and also contact angle measurements were carried out. The coatings made from a fatty acid exhibited good barrier properties towards oxygen gas. Moreover, these coatings presented a higher contact angle value than the one obtained directly for the substrate without coating; this can be likely due to the hydrophobic nature of fatty acid and the recrystallization of fatty acid during the drying process.     

Molecular Finger Printing of Nutra-Coconut Oil with Improved Health Protective Phytoceuticals and its Efficacy as Frying Medium

Coconut oil is rich in medium chain triglycerides but lacks polyunsaturated fatty acids (PUFA) and bio‐active phytoceuticals. In the present work nutra‐coconut oil was prepared by blending coconut oil and flaxseed oil (70:30) and adding 3000 ppm of flaxseed cake concentrate using ethanol, methanol and 20 % aqueous ethanol. The concentrate prepared from flaxseed was from ethanol as it gave maximum yield. The different bio‐active molecules in flaxseed concentrate observed are polyphenols (39.04 %), tocopherols (4.37 %), ferulic acid (0.17 mg g^?1), p‐coumaric acid (2.24 mg g^?1), chlorogenic acid (16.11 mg g^?1), gallic acid (8.58 mg g^?1), sinapic acid (0.64 mg g^?1) and secoisolariresinol (30.13 mg g^?1). The nutra‐coconut oil was found to have polyphenols (2.86 %), tocopherols (442.96 ppm) and antiradical activity (94 %). The PUFA content was found to increase in nutra‐coconut oil significantly (p < 0.05) (2–22 %). The FT‐IR spectra of nutra‐coconut oil revealed that the peak at 3009 and 1651 cm^?1 was associated with the presence of unsaturated fatty acids. There was no significant (p > 0.05) difference observed in sensory attributes of snack food fried using coconut oil and nutra‐coconut oil indicating that the later could be used as a frying medium and useful for food processing industries.     

Behavioral and electrophysiological responses of natural enemies to synomones from tea shoots and kairomones from tea aphids,Toxoptera aurantii

Olfactometer bioassays and electrophysiological studies showed that the lacewing, Chrysopa sinica, the aphid parasitoid, Aphidius sp., and the coccinellid, Coccinella septempunctata, all responded to volatiles from tea aphids, Toxoptera aurantii, to hexane or ether rinses of tea aphid cuticles, and to synomones released by aphid-damaged tea shoots, as well as to the tea shoot–aphid complex. Each natural enemy spent more time searching on a filter paper treated with tea aphid honeydew than on a blank control filter paper. The interaction between synomones from aphid-damaged shoots and kairomones from tea aphids enhanced the responses to the plant–host complex. There was a significant, logistic dose–response relationship between the number of natural enemies responding and the odor stimulus concentration. Volatile components from the plant–host complex, obtained by air entrainment, were identified by their mass spectra and retention times and confirmed by comparison with standard samples. These were (Z)-3-hexen-1-ol, benzaldehyde, (E)-2-hexenal, (Z)-3-hexenyl acetate, ocimene, linalool, geraniol, indole, and (E)-2-hexenoic acid. The main components in a hexane rinse from tea aphid cuticle were benzaldehyde, undecane, 2,5-hexanedione, 2,5-dihydrothiophene, linalool, 4-methyl-octane, and eicosane, whereas the main components from an ether rinse were (E)-2-hexenoic acid, heptadecane, pentadecane, eicosane, tetratetracontane, and nonadecane. Benzaldehyde elicited the strongest responses from natural enemies in the olfactometer and the largest electroantennogram (EAG) responses. While the amount of odor was small, Coccinella septempunctata was slightly more sensitive than Chrysopa sinica and Aphidius sp. An increase in doses of benzaldehyde, (E)-2-hexenal, and (Z)-3-hexenyl acetate caused the EAG responses of each natural enemy to decrease. When the doses of (Z)-3-hexen-1-ol, linalool, and geranoil increased, EAGs of Chrysopa sinica and Aphidius sp. increased, but EAGs of Coccinella septempunctata decreased. When the dose of indole increased, EAGs of Coccinella septempunctata decreased, but those of Aphidius sp. increased. This study demonstrates that tea shoot–aphid complexes emit volatile synomones, while the odors from tea aphids, aphid cuticle extracts, and tea aphid honeydew contain kairomones, to which the natural enemies show a logistic dose–response.     

原子吸收法测量茶叶、茶树叶和土壤中微量元素

采用原子吸收方法对梅家坞茶叶，茶树叶以及其生长的土壤中的10中微量元素进行了测量。结果表明茶树是富Ca富Mn植物，茶叶中与人体健康密切相关的微量元素含量丰富，多饮茶有益健康。     

Effect of extraction methods on lipid yield and fatty acid composition of lipid classes containing γ-linolenic acid extracted from fungi

The effect of extraction procedures on the lipid yield and fatty acid composition of total lipid and main lipid structures (phospholipids, diacylglycerols, triacylglycerols, free fatty acids, and sterol esters) of fungal biomass (Mucor mucedo CCF-1384) containing γ-linolenic acid (GLA) was investigated. Seventeen extraction methods, divided into three groups, were tested: six with chloroform/methanol, five with hexane/alcohols, and six with common solvents or mixtures. The chloroform/methanol procedure (2∶1) was selected as standard, where lipid yield (TL/DCW, total lipid per dry cell weight) was 17.8%, considered to be 100% of lipids present. All chloroform/methanol extractions yielded more than 83% recorvey of lipids. Use of hexane/isopropanol solvent systems led to a maximum of 75% recovery. The best lipid yield was achieved by a two-step extraction with ethanol and hexane (120%). Extraction efficiency of the other solvent systems reached a maximum of 73%. Triacylglycerols were the main structures of lipid isolated; only methanol-extracted lipid contained 58.5% phospholipids. The fatty acid content of total recovered lipid was variable and depended on both the lipid class composition and the solvent system. GLA concentrations in total lipids isolated by hexane/alcohol procedures (7.3–10.7%) are comparable with classical chloroform/methanol systems (6.5–10.0%). The maximal GLA yield was obtained with chloroform/methanol/n-butanol/water/0.1 M ethylenediaminetetraacetic acid (EDTA) (2∶1∶1∶1∶0.1, by vol) and after two-step extraction with ethanol and hexane (14.3 and 13.7 g GLA/kg DCW, respectively). The highest GLA content was analyzed in the phospholipid fraction (16.1%) after using chloroform/methanol/n-butanol/water/0.1 M EDTA (2∶1∶1∶1∶0.1, by vol). Remarkably low concentrations of polyunsaturated fatty acids were determined in the free fatty acid fraction.     

必需脂肪酸在美容化妆品中的应用

必需脂肪酸（EFAs）可以使皮肤增益，加强细胞膜结构与功能，维持并恢复皮肤天然屏障，预防皮肤刺激和炎症，以及增强细胞膜的通透性。详述了必需脂肪酸的新陈代谢过程和其在美容化妆品中的应用。