首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Antioxidants play an important role in inhibiting and scavenging free radicals in human, providing protection against cellular damage in relation to cancer initiation. Seaweeds have been proved to have high antioxidant activity. Thus, this research was carried out to determine the antioxidant and anticancer properties of edible red seaweed, Gracilaria manilaensis (Gracilariales, Rhodophyta). The extracts were prepared by Soxhlet extraction using organic solvents with different polarities. The antioxidant activities of extracts were determined in terms of their flee radical scavenging activity (RSA IC50) and total phenolic content (TPC). The cytotoxic activity of extracts were tested against human ovarian cancer cell line (Caov-3), human breast cancer cell line (MDA-MB-231 and MCF-7), human cervical cell line (HeLa), mouse fibroblast cell line (L929) and Madin-Darby canine kidney (MDCK) and the cell viability after 72 h incubation was determined by methylene blue assay. The findings showed that acetone extract has the lowest DPPH IC50 value followed by ethyl acetate extract. Both extracts also showed high values of TPC. Dichloromethane extract had the strongest cytotoxic on MDA-MB-231 (53.90 μg/mL ± 5.59 μg/mL) and HeLa (95.50 μg/mL). While, acetone and ethyl acetate extracts were cytotoxic on MCF-7 (66.07 μg/mL) and Caov-3 (69.67 μg/mL ± 13.94 μg/mL). It could be concluded that the antioxidant and cytotoxic activities of G. manilaensis were influenced by the types of solvents used and thus had a potential to develop as a cancer chemoprevention or anticancer agent against selected cancer.  相似文献   

2.
Avocado oil is a relatively new oil in the market and is highly appreciated by the consumers because of its fine aroma, pleasant taste and health benefits. A study on the characterization of commercial avocado oils produced in Chile was conducted in order to discuss their quality parameters. The study was applied to two marketed avocado oils. The main analytical parameters evaluated to the oils were: fatty acid composition, total chlorophylls, total carotenoids, tocopherols, acid value, peroxide value, total phenolic compounds, polar compounds, oil stability, UV absorption and 3.5-stigmastadiene content. The fatty acid compositions of the studied oils were according with oil composition of pulp pure of avocado fruit. The analysis of tocopherols by high performance liquid chromatography (HPLC) revealed significant differences between the avocado oils studied. Total phenolic compounds, oil stability, UV Absorption characteristics, peroxide value, acid value, tocopherols content, total chlorophylls, total carotenoids and polar compounds were also significantly different between the commercial studied oils. All the above results show a different quality between both commercial avocado oils, showing that the sample C has worse values for the parameters of quality as those required by legislation in many countries. Also, 3.5-stigmastadiene content shows high concentration for one of the commercial avocado oil evaluated which demonstrates the presence of refined oil or that the oil has been submitted to high temperatures. On the other hand it is remarkable that despite the fact that there are many differences in quality parameters, both oils are labeled and marketed as extra virgin quality oils, demonstrating the need to regulate the classification of appreciated oils by the consumers.  相似文献   

3.
Although many aroma components have been identified in green tea leaves, the aroma compounds contributing to green tea's characteristic odor have not yet been reported. The authors recently reported that aroma components with a matcha-like odor are present in both green tea and black tea prepared from the Sayamakaori tea cuttivar. This matcha-like odor is similar to the odor of commercial available matcha (high-quality powdered green tea), and is a specific odor feature of green tea leaves. At present, the green-tea odor is thought to arise from the combination of a large number of constituents. Recent reports indicate that a complex interaction between olfactory receptors and odorants is important for the evaluation of the odors. Taking into consideration these findings, the authors investigated the aroma profile of green tea, focusing on the characteristic molecular structures of the constituents that give matcha-like odor. Using a combination of organic synthesis and gas chromatography-mass spectrometry plus gas chromatography-olfactometry, the authors identified aroma components with matcha-like odors in five other tea cultivars. This investigation also revealed that several compounds with a formyl group were important constituents of the aroma of green tea leaves, although the odor of each constituent was not individually similar to the tea's overall aroma. The authors found for the first time a group of key components that have the matcha-like odor.  相似文献   

4.
Consuming a cyanogenic plant is an etiological factor to the persistence of iodine deficiency in the post salt iodization phase. Ghana, notably the Northern belt, still reports of iodine deficiency after 14 years of mandatory consumption of iodized salt by an Act of Parliament. The study aimed at determining the cyanide contents of leaves of commonly consumed cassava varieties in Ghana and investigating the effects of some environmental factors on cyanide content. Three communities each from Southern, Middle and Northern Ghana served as the study sites from where young, non-diseased and fully-spread cassava leaves were sampled from plants of commonly consumed cassava varieties. Cyanide was analyzed by the standard color~metric method based on the chloramine-T/pyridine-barbituric acid protocol (4500-CN E). Cassava leaves from Northern Ghana had significantly higher mean cyanide content (177.22 ± 20.82 ppm) than those from Middle (130.83± 33.00 ppm) and Southern Ghana (127.24 ± 37.54 ppm) (P 〈 0.001). Two-factor ANOVA showed significantly higher adverse environmental effects on cyanide contents of leaves of unimproved cassava varieties than improved ones (R2 = 0.627, P = 0.023). From multiple regression analysis, temperature was the most significant environmental factor explaining 33% of the variability in cyanide content (R2 = 0.331, P = 0.002), followed by altitude (R2 = 0.106, P = 0.049) and rainfall (R2 = 0.084, P = 0.062). The high cyanide contents of cassava leaves from Northern Ghana, due principally to the high atmospheric temperature, may be a contributory factor to the high prevalence of goiter and the persistence of iodine deficiency in that geographic region.  相似文献   

5.
In our context, and in the goal to valorize the Pistacia atlantica species Desfthat grows spontaneously in Algeria occidental except the coastline, and that is used by the nomadic populations in their daily consumptions, we are thinking about drying its leaves. Here, the biochemical analysis of dried leaves ofPistacia atlantica is determined, the sorption is other ms are of great importance in the food industry, especially in the drying; the sorption isotherms of pistachio leaves were measured by the gravimetric method at three temperatures 40, 50 and 60 ℃. The equilibrium was achieved after eight days for desorption and seven days for adsorption with water activity ranging from 5% to 90%. Only the GAB and Peleg models were found to be the most suitable for describing the sorption curves. The isosteric heat of sorption of Pistacia atlantica leaves decreases with an increase in moisture content and was found to be an exponential function of moisture content for adsorption and desorption. The pistachio leaves could be considered as a rich natural source of valuable nutriments (carbohydrates, proteins and lipids); lipid fraction is equal to 2.25%; proteins are the second macronutriment that predominates in these sheets: 4.35%; accordingly carbohydrates content was about 25.77%.  相似文献   

6.
铝对氟在茶树体内吸收与分配的影响   总被引:1,自引:0,他引:1  
为了探讨铝(Al3+)对茶树吸收氟(F)的累积特性,研究溶液培养条件下,不同浓度Al3+及c(Al3+):c(F-)比例对茶树吸收富集F的影响。结果表明:低浓度Al3+ (1.05~5.26mmol/L,c(Al3+):c(F-)=1:10~1:2)促进了F在茶树根部的富集,主要以F离子态形式被茶树吸收;而高浓度Al3+ (10.52~31.57mmol/L,c(Al3+):c(F-)=1:1~3:1)抑制了F在茶树根部的富集,主要以Al/F络合态形式被茶树吸收。不同浓度Al3+促进了F在茶树叶部的富集。培养液中c(Al3+):c(F-)≥1时(c(Al3+)≥10.52mmol/L),抑制了茶树根部对F的吸收富集,而c(Al3+):c(F-)<1时(c(Al3+)≤5.26mmol/L),促进了茶树根部对F的吸收富集。Al3+促进了茶树体内F向地上部分转移,尤以c(Al3+):c(F-)为1:1、1:3、1:5时,F从茶树根部向地上部分转移系数最高。  相似文献   

7.
Beef tallow is a byproduct of the slaughter industry. As a consequence, meat producer countries obtain a high amount of this low value-added fatty material. In Uruguay, it is generally used for food purposes or for biodiesel production. Globally, around half of the beef tallow produced worldwide is used for the manufacturing of food. To the best of our knowledge there are no published studies concerning the stability of beef tallow when exposed to high temperatures. The aim of this work was to study some Uruguayan beef tallow brands and compare its stability with that of the most frequently used frying oils in Uruguay (sunflower high oleic, rice bran and sunflower oil) to assess its suitability for frying. Stability was assessed by the oxidative stability index and thermoxidation in absence of food. Even though beef tallow's inherent stability indicated that it should be highly stable to oxidation, the majority of the analyzed samples exhibited a similar or lower stability than sunflower high oleic. This might be explained by a different composition in pro-oxidants and/or antioxidants between the beef tallows and the oils. According to the thermoxidation assays, which are carried out in similar conditions to those of a frying process, three of the beef tallow samples, sunflower high oleic and rice bran oil would be similarly suitable for frying, while sunflower oil and the other two samples of beef tallow evidenced a lower thermoxidative stability, thus not being recommended for this use.  相似文献   

8.
Hyuganatsu is a typical Japanese citrus with desirous smell and edible albedo. The objectives of this study are to establish a method for softening hyuganatsu peel without heating and a process for making a high pressure-induced (HP-) marmalade and to compare with heat-induced (H-) marmalade and citrus shaddock family marmalade. Firmness of peel was (greatest to least) pressurized at 500 MPa for 30 min, soaked in citric acid solution at pH 2.7 for 24 h, and boiled for 10 min, respectively. The cell walls of flavedo and albedo did not loosen after pressurization. However, after soaking or heating, the middle lamella of albedo separated. When flavedo was soaked at pH 2.7, 9.3% of pectin was extracted. The amount of naringin was the least in hyuganatsu 〈 pummelo 〈 grapefruit), and juice sacs 〈 flavedo 〈 segment walls 〈 albedo, respectively. Thus, marmalade was processed. Albedo, segment walls and juice sacs of hyuganatsu were homogenized with citric acid solution (pH 2.7) and mixed with sliced flavedo. Then it was soaked for 24 h at pH 2.7. Sucrose was then added (final sugar 50%), vacuum packed, then pressurized for 30 min at 500 MPa or boiled for 10 min, respectively. There was no significant difference in sensory evaluation between HP- and H-marmalade. However, the color, transparency and total evaluation of HP-marmalade were better than H-marmalade. Consequently, total evaluation of hyuganatsu-HP-marmalade was rated highly. So, hyuganatsu was considered to be more suitable for marmalade because it was more palatable than the others.  相似文献   

9.
Investigations were conducted to establish effects of fermentation and drying on the fermentation index (FI) and cut test of pulp pre-conditioned Ghanaian cocoa beans using a 4 x 3 full factorial experimental design with the principal factors being pod storage (0, 3, 7 and 10 d) and fermentation time (0, 3 and 6 d) to study the changes occurring during the fermentation process. The study also used a 4 x 3 full factorial design with pod storage (0, 3, 7 and 10 d) and drying time (0, 3 and 7 d) being the principal factors investigated to study the changes occurring during the drying process. FI and cut test of the beans were studied during fermentation as well as the drying process. FI of the beans increased significantly with pod storage and fermentation but decreased slightly during drying. FI of the unfermented beans increased slightly from 0.674 for the unstored pods to 0.763 after 10 days of pod storage. The FI of the fermented beans (six days fermentation) also increased from 1.390 for the unstored pods to 1.424 for pods stored for 10 days. It decreased from 1.389 at the start of drying for the unstored pods to 1.105 for pods stored for 10 days at the end of drying (seven days). FI of all the beans were however, above 1.0 at the end of fermentation and drying for all pod storage treatments. Cut test revealed that storage of pods for 3, 7 and 10 days increased the percentage of brown beans by 66%, 94% and 72%, respectively, by the sixth day of fermentation. Percentage of brown beans decreased to 61%, 76% and 63%, respectively, for pods stored for 3, 7 and 10 d at the end of drying (seven days). Cocoa pods can be stored for up to 10 days, fermented for six days and dried for seven days with the necessary formation of brown pigments characteristics of well fermented and dried cocoa beans.  相似文献   

10.
Changes in nib acidity, protein and sugar concentration during roasting of pulp pre-conditioned and fermented cocoa (Theobroma cacao) beans were investigated. A 4 - 4 full factorial design with the principal experimental factors as pod storage (0, 3, 7 and l0 d) and roasting time (0, 15, 30 and 45 min) were used. The roasted samples were evaluated for pH, titratable acidity, protein content and sugars concentrations using standard methods. Increasing pod storage caused consistent increases in pH with concomitant decreases in titratable acidity, whereas increasing roasting time caused only marginal and insignificant changes in pH but significantly decreased the titratable acidity. The protein content decreased significantly (P 〈 0.05) with increasing pod storage and roasting time. Reducing sugars increased marginally with increasing pod storage treatments whiles increasing roasting time significantly (P 〈 0.05) decreased the reducing sugars of the beans for all pod storage. The non-reducing sugar and total sugar content of the beans decreased significantly from 3.493 mg/g to 2.641 mg/g and from 9.284 mg/g to 8.891 mg/g, respectively, for pods stored from 0 to 10 days while roasting time caused slight decreases in non-reducing sugars with a considerable decrease in total sugars. Pod storage up to seven days decreased considerable the nib acidity (non-volatile acids), non-reducing sugars and total sugars while roasting up to 45 min at 120 ℃ caused dramatic decreases in the nib acidity and reducing sugars with only marginal decreases in non-reducing sugars and total sugars.  相似文献   

11.
The new Nordic diet (NND) was designed by gastronomic, nutritional and environmental specialists to be a palatable, healthy and sustainable diet containing 30%-40% less meat than the average Danish diet (ADD), ≥ 75% organics, and more locally grown wholegrain products, nuts, fruit and vegetables. In this study, the NND was based on economic modelling to represent a "realistic NND bought by Danish consumers". The objective was to investigate whether the ADD-to-NND diet-shift has environmental consequences that outweigh the increased consumer cost of the diet-shift. The diet-shift reduced the three most important environmental impacts by 16%-22%, mainly caused by reduced meat content. The surcharge to consumers of the ADD-to-NND diet-shift was ∈216/capita/year. In monetary terms, the savings related to the environmental impact of the diet-shift were ∈151/capita/year. 70% of the increased consumer cost of the ADD-to-NND diet-shift was countered by the reduced socioeconomic advantage associated with the reduced environmental impact of the NND.  相似文献   

12.
The efficiency of using nanostructured silver in technological processes of making red wine has been studied with the purpose of substituting sulfur dioxide. For preparation of research objects, we used dry wine material of red grape variety "Saperavi". After completion of malolactic fermentation, the second racking the wine material off the lees and its treatment with antiseptics were carried out. Sulfur dioxide (Kadifit) and different doses of nanostructured silver were used. Microbiological investigation was performed on the presence of lactic bacteria after completion of malolactic fermentation and racking off the lees. The investigation of phenolic compounds was conducted at the following stages of technological processes: (1) after completion of alcoholic fermentation and racking off the lees; (2) after completion of malolactic fermentation; (3) after the second racking off the lees and treatment with antiseptics. By means of the HPLC analysis, the amounts ofcatechins, phenolcarbonic acids and flavonols were determined. It has been established that after conduction of malolactic fermentation in the process of racking the wine material off the lees and storage, the application of 0.6 mg/L of nano-silver for blocking of lactic-acid bacteria and inhibition of oxidation of phenolic compounds has the same effect as sulfitization with 50 mg/L of Kadifit.  相似文献   

13.
The flesh of spaghetti squash separates into strands when cooked. The purpose of this paper is to investigate the cause of strand separation (during cooking) by soaking for 24 h at 35 ℃ in solutions with three kinds of pectin extractant. The changes in strand separation, firmness, histological structure and the pectin of flesh during soaking in 0.01 N HCI solution (pH 2.0), 0.035 M ammonium oxalate solution (pH 4.0) or 2% sodium hexametaphosphate solution (pH 4.0) were investigated. When flesh was soaked in the HCI solution, the separation into strands and removal of calcium and magnesium were greater than that soaked in other pectin extractants. High methoxyl pectin was extracted by soaking in HC1 solution (pH 2.0) due to removal of polyvalent cations. This result shows that high methoxyl pectin glues strands together in the flesh of spaghetti squash. The shape of the cells which constituted strands was round; on the other hand, that of cells surrounded strands was elongated. When cooked in boiling water or soaked at pH 2.0, the shape of the former cells was maintained, but the latter cells, which contributed to adhesion between strands, broke down. Thus, the flesh separated into strands. When flesh was boiled for 15-30 min, pectin degraded and dissolved in the cooking solution; consequently, the flesh separated into strands and also the middle lamella of cell walls of strands separated. However, pectin remaining in strands maintained their crispness.  相似文献   

14.
Afyon kaymak (milk cream) is traditional dairy product of Afyon city which is a junction of Middle Anatolia and West regions and famous with its thermal tourism and food. However, challenging production process led Afyon kaymak to lose its importance. Although buffalo milk is the raw material of traditional Afyon kaymak, cow milk can be used in the process. In traditional process, milk is filtered with double cheesecloth and gotten into the aluminum or tinned copper milk cream pans where the capacity is around 2.5-3.0 L. Half-filled pan is warm up to 90-95 ℃. Pans are carried to cool area and left until cooling. Milk cream on the cooled pans is lined by a pin. New milked milk is added to the lined cream in pans and heated for 1 h. It is covered and held on for 6-8 h. While holding period is until afternoon on summer time, it is until mid-afternoon in winter. Covers of the pans are opened and hold in a cool place until morning and, thus, cream is chilled. Cream layer on pans are lined and gotten out of pans. Cream as circle is divided into four pieces and left to the cream package after turning down. In this review, we aimed to give some information about Afyon kaymak and its production methods.  相似文献   

15.
Through experimental analysis of the liquid flows in a flow channel instrument, prompt evaluation of the physically defined viscosity of non-Newtonian liquid foods was investigated for development into a structurally simple and easy-to-use viscometer. For Newtonian and non-Newtonian test liquids, a relation between the friction coefficient and Reynolds number, which was dimensionless as derived from an expression of analysis as a gravity current, indicated a condition under which the flow in the instrument was laminar and under which an average shear rate was on the order of less than 1 s~. Prediction organized based on this empirical relation reproduced practically the flow curve determined for the liquid foods using a rotor type viscometer. Utilization of the channel instrument as a viscometer was formulated in terms of physical meanings of measurements such as the flow length and elapsed time.  相似文献   

16.
The levels of five mycotoxins (MT): deoxynivalenol (DON), T-2-toxin (T-2), zearalenone (ZEA), aflatoxin (Aft), ochratoxin A (OTA) were measured in malting barley and malt samples by enzyme immunoassay (ELISA), using test systems RIDASCREEN FAST (R-Biopharm, Germany). 40 samples of malting barley, mainly from the Central part of European Russia and fewer from the Southern part of, and also some samples from Altai (Asian Russia) were analyzed during 2007-2011 years as well as 120 samples of malt from Russian malting companies. It was found that 17% of barley samples were contaminated with MT; in two cases (5%), the MT concentration exceeded maximum allowable levels (MAL). Among malt samples in more than half (in 56%) MT were detected, in 9% of samples, the MT concentration exceeded MAL (Aft-3 incidents, T-2-3 incidents, OTA-2 incidents, ZEA-1 incident). Maximum levels ofmycotoxins in malt were found to be higher than those in barley. These facts support the idea about risky conditions during malting processing.  相似文献   

17.
Goat milk ice cream was made with various sources of fat ingredients such as cream, soybean oil, rice bran oil and butter with the purpose of seeking the fat ingredient source instead of fat source from cow origin. The physical properties and the sensory evaluation of ice cream were then investigated. The firmness of goat milk ice cream mixed with rice bran oil, butter and cream were not significantly different before aging at 4 ℃ for 8 h. All of them gave the overrun between 51%-63% and the one with butter was the highest. The meltdown rate of all types of fat ingredients are not significantly different, being in the range of 0.86-0.88 g/min. According to sensory evaluation, the cow milk ice cream with cream was mostly accepted in all attributes such as appearance, smoothness, whiteness, melting in mouth and odor while the goat milk with cream and butter are the second and third. Nevertheless, the goat milk ice cream with soybean oil and rice bran oil were moderately accepted in overall preferences.  相似文献   

18.
Since Korea-Japan annexation in 1910, Japan has promoted the migration and/or tourism into colonial Chosun (old Korea) as an efficient cultural strategy for extending imperialism into Korean peninsula. In many tour guide books, the gisaeng (Korean female entertainers) was not only a symbol of Chosun tradition, but a main icon of Chosun tourism. The high class Korean-styled restaurants (yorijoem) were established as tourist attraction for Japanese inlanders, with singing and dancing gisaengs, ondol (Korean heating floor) house and Korean authentic cuisine, etc. The aim of this paper is firstly to explore the existential change of gisaengs in the yorijoem through its spatial significance in the 1930s, and secondly to explore the identity of Seoul local food culture and its metamorphosis under the colonial modernity.  相似文献   

19.
The aim of this study was to apply the existing techniques that enable examination ofmacadamia kernels to provide a better understanding of physico-chemical properties of kernels during postharvest processing. These techniques, such as X-ray tomography, could be applied for quality monitoring in the macadamia industry. The objectives of this study were to investigate the browning centre symptoms that usually occur in macadamia nuts-in-shell. The applied techniques included confocal microscopy, X-ray tomography and magnetic resonance imaging (MRI). Five different varieties of macadamia nuts (A38, 246, 816, 842 and Daddow) were selected to include distinct characteristics, such as drop pattern and growing location. Analysis of the microstructure of kernels by confocal microscopy showed the distribution of possible brown pigment compounds as well as the distribution of lipids, carbohydrates and proteins inside macadamia cells. Physical properties data, including shell density and seed to volume ratio, were obtained by X-ray tomography. Magnetic resonance diffusion tensor imaging used in this study showed marked differences in microstructure which indicate that different varieties exhibit different microstructures expressed as fraction ofanisotropy and apparent diffusion coefficient that appear to be related to the occurrence of the brown centre. Hence, the findings of this study have potential to improve the existing postharvest techniques used in the macadamia processing industry. They will be of benefit to the industry in terms of improved quality control and cost reduction.  相似文献   

20.
This paper presents the influence of solvent polarity and extraction conditions on the extraction of total flavonoid, total phenolic and antioxidants from Averrhoa bilimbi. The experiment was performed using a different solvent at different extraction conditions, including extraction time (15-240 min), temperature (30-70 ℃) and agitation speed (50-300 rpm). Results showed that yields of extraction varies with solvent polarity. Extraction using 50% aqueous methanol gives the highest antioxidant activity and flavonoid content. The highest total flavonoid content (193.3 μg quercetin equivalent/g dry weight), total phenolic content (717.8 μg gallic acid equivalent/g dry weight) and antioxidant activity (77%) was achieved using 50% methanol, at 70 ℃ and agitation speed of 300 rpm. This work may be useful for obtaining higher bioactive compounds during the extraction process of A. bilimbi.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号