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1.
Exogenous pigments produced by ascomycetous filamentous fungi belonging to the genera Penicillium, Epicoccum, and Monascus, preselected based on chemotaxonomic knowledge, have been extracted and characterized by quantitative colorimetry. The color characteristics of the fungal extracts were compared to water soluble natural colorants derived from sources currently in use. The tested fungal extracts also included some commercially available Monascus colorants. The a values for the fungal extracts were found to be both positive and negative, the b values were found to be positive, while the hue angles of the fungal color extracts ranged from 40 to 110 indicating the color distribution of fungal extracts over the red-orange-yellow region of the CIELAB color space. The fungal extracts exhibited additional color hues in the red spectrum and similar hues in the yellow spectrum as compared to the reference natural colorants. They were also found to be similar or brighter in terms of chroma to some of the reference natural colorants. Principal component analysis was performed to group and distinguish different colors based on the a and b values. The fungal color extracts could be grouped in accordance with the similarity or difference in the color to those of the existing natural colorants. The diversity of colors was not only found among different fungal genera and/or species but also within the same species on changing the media. There was a marked change in the color composition of the extracts resulting in relatively different hues. Our results, thus, indicate that there exists pigment-producing genera of ascomycetous fungi other than Monascus that produce color shades in the red and the yellow spectra in addition or similar to reference colorants. These color shades could add to the color palette of the natural colorants currently in use. In addition, the multivariate approach in distinguishing and classifying the colorants was shown to be a very useful tool in colorimetric comparison of colorants.  相似文献   

2.
The colors and color patterns of soils are widely used to infer other soil properties. It is desirable to understand, at least semiquantitatively, the effect various pigments have on soil color. The purpose of this study was to determine how hematite and goethite pigments influence soil color. We prepared simulated soil mixtures consisting of kaolinite and 2.5, 5, 10, 20, 40, 80, 160, 320, 640, and 1000 g kg?1 of pigment (either a synthetic goethite, one of two synthetic hematites, or a mixture of goethite and hematite). We determined the reflectance spectra of the samples, and calculated their colors in the Munsell system. For hematite and goethite pigments mixed with kaolinite, more than half of the change in hue occurred as the Hm/(Hm+Gt) ratio increased from 0 to 0.25, and hue changed relatively little as the Hm/(Hm+Gt) ratio increased from 0.50 to 1.00. Most of the change in color occurred as pigment content increased from 2.5 to 160 g kg?1. Doubling of pigment content from 160 to 320 g kg?1 had very little impact on the colors of the mixtures, while further increases in pigment content between 320 and 1000 g kg?1 caused some changes in color, but less than for the 2.5 to 160 g kg?1 range. A one unit increase in chroma corresponded approximately to a doubling of pigment content in the series 2.5, 5, 10, 20, 40, 80, 160 g kg?1 for the goethite as well as the hematite pigments studied. For one hematite, hues became progressively redder and changed by more than 5 units of hue as pigment content increased from 0.25 to 160 g kg?1.  相似文献   

3.
Characterization of carotenoids in juice of red navel orange (Cara Cara)   总被引:10,自引:0,他引:10  
High-performance liquid chromatography with photodiode array detection was applied for the separation and characterization of carotenoids from a red-fleshed navel orange (Cara Cara). Carotenoid pigments were extracted using hexane/acetone/ethanol and saponified using 10% methanolic potassium hydroxide. More than 29 carotenoid pigments were separated within 60 min using a ternary gradient (75% acetonitrile/25% methanol, methyl tert-butyl ether, and water) elution on a C(30) reversed-phase column. The presence of lycopene (3.9 +/- 1.1 ppm) and a relatively large percentage of beta-carotene were distinct differences in the pigment profile of this red navel orange juice as compared to the profile of standard navel orange juice. The juice color in the red navel was much deeper orange than that from navel orange; hue angle ranged from 84.1 to 89.4 for red navel compared to 98.2 to 100.5 for standard navel.  相似文献   

4.
Total phenolics, ascorbic acid, and betalain contents of differently colored cactus pear clones (nine Opuntia ficus-indica [L.] Mill. clones and one O. robusta Wendl. clone) were investigated and related to their respective antioxidant potential assessed by Trolox-equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) assays. TEAC and ORAC values were very highly correlated with each other and also with values for total phenolics, betalain contents, and ascorbic acid concentrations. Total phenolics had the greatest contribution to ORAC and TEAC values. High-performance liquid chromatography (HPLC)-diode array detector (DAD)-tandem mass spectrometry (MS/MS) measurements of cactus pear juices permitted the differentiation of the clones based on variations in pigment patterns and betalain concentrations. The red and yellow betalains were absent in lime green colored cactus fruits. The ratio and concentration of these pigments were responsible for the yellow, orange, red, and purple colors in the other clones. Progeny of purple and lime green colored parents were characterized by 12% and 88% of plants bearing lime green and purple fruit, respectively. This implies that the genes for betalain production were lacking in the lime green fruits but could be provided by a parent with a complete set of genes, that is, purple fruits. Besides known pigments typical of Cactaceae, two unexpected betalains were identified. Whereas gomphrenin I was found for the first time in tissues of cactus plants, methionine-betaxanthin has never been described before as a genuine betalain. In addition to their alleged health-promoting properties, various combinations of yellow betaxanthins and red-purple betacyanins may allow the development of new food products without using artificial colorants.  相似文献   

5.
Two newly formed yellow pigments that revealed unique spectral features were detected and isolated from an aged Port red wine by TSK Toyopearl HW-40(s) gel chromatography and characterized by UV-visible spectrophotometry, 1H NMR and 13C NMR, and mass spectrometry (LC-ESI/MS). The UV-vis spectra of these pigments showed maximum absorption at 478 nm that is significantly hypsochromically shifted from those of original grape anthocyanins and other pyranoanthocyanins, exhibiting a more yellow hue in acidic solution. The structures of these pigments correspond to methyl-linked pyranomalvidin 3-glucoside and its respective coumaroyl glucoside derivative. They were shown to arise from the reaction between acetoacetic acid and genuine grape anthocyanins. Isolation and NMR identification using 1D and 2D NMR techniques are reported for the first time for this new family of anthocyanin-derived yellow pigments occurring in red wines.  相似文献   

6.
Objective measurement of red grapefruit juice color   总被引:1,自引:0,他引:1  
The color properties (CIE Lab, hue, and chroma) of 90 red grapefruit juices were studied by tristimulus reflectance measurement for two growing seasons. Juices were prepared from six red grapefruit cultivars including Ruby Red, Rio Red, Star Ruby, Ray Ruby, Flame, and Marsh Red grown in Florida. Very wide varietal and seasonal variations on juice color were observed, and most notably, CIE a values varied widely from -1.41 to 9.06 (CV = 82.6%). Lycopene is the major colored pigment in red cultivars with lesser amounts of beta-carotene as determined by HPLC on a carotenoid C(30) column with gradient elution using MeOH and MTBE. The highest correlation coefficients (r = 0.963) found between CIE a values and lycopene contents in juices from all cultivars combined suggest the possibility that the CIE a value would be a good indicator for pigmentation in red grapefruit juice.  相似文献   

7.
This study aimed to identify the pigment composition of black carrot (Daucus carota ssp. sativus var. atrorubens Alef.) cultivars Antonina, Beta Sweet, Deep Purple, and Purple Haze. Cyanidin 3-xylosyl(glucosyl)galactosides acylated with sinapic acid, ferulic acid, and coumaric acid were detected as major anthocyanins by high-performance liquid chromatography with diode array detection (HPLC-DAD) and with electrospray ionization multiple mass spectrometry (HPLC-ESI-MS(n)) analyses. The preparative isolation of these pigments was carried out by means of high-speed countercurrent chromatography (HSCCC). The color activity concept was applied to the isolated anthocyanins at three pH values. Cyanidin 3-xylosyl(sinapoylglucosyl)galactoside was found to exhibit a lower visual detection threshold and a higher pH stability than cyanidin 3-xylosyl(feruloylglucosyl)galactoside and cyanidin 3-xylosyl(coumaroylglucosyl)galactoside. The color parameters of the fresh roots of the four cultivars were described by the CIELab coordinates L* (lightness), C* (chroma), and h(ab) (hue angles). Total phenolics varied among the cultivars and ranged from 17.9 to 97.9 mg gallic acid equivalents (GAE)/100 g fresh weight (fw). For the content of monomeric anthocyanins, values between 1.5 and 17.7 mg/100 g fw were determined.  相似文献   

8.
A recently developed food, the so-called ultrafrozen orange juice (UFOJ), has been characterized in terms of carotenoid pigments, ascorbic acid, and color. The juice, obtained from Valencia late oranges, is frozen immediately after the squeezing of the oranges, which makes it a product showing good organoleptic and nutritional quality. In relation to the carotenoid profile, it was observed that the 5,6-epoxy carotenoids violaxanthin and antheraxanthin (specifically (9Z)-violaxanthin and (9Z)- or (9'Z)-antheraxanthin), were by far the major pigments and that dihydroxycarotenoids predominate over monohydroxycarotenoids. As far as color was concerned, it was seen that there were little differences among the juices analyzed. The hue of the samples, ranging from 77.19 degrees to 80.15 degrees and from 79.99 degrees to 83.04 degrees depending on the kind of instrumental measurement, and their chroma (ranging from 63.06 to 72.25 and from 44.40 to 58.38) revealed readily that the juice surveyed exhibited a deep orangeish coloration, the color coordinate best correlated with the total carotenoid content being b*. The levels of ascorbic acid ranged from 332.64 to 441.44 mg/L, with an average content of 391.06 +/- 28.86 mg/L.  相似文献   

9.
The effectiveness of seven phenolic compounds (catechin, epicatechin, procyanidin B2, caffeic acid, p-coumaric acid, myricitrin, and quercitrin) as copigments of malvidin 3-glucoside, the major anthocyanin in red wines from Vitis vinifera, using a copigment/pigment molar ratio of 1:1 was assayed in model wine solutions under the same conditions (pH=3.6, 12% ethanol). The stability of the copigment-pigment complexes formed was studied during a storage period of 60 days at 25 degrees C. Tristimulus colorimetry was applied for color characterization of the copigmentation process, and HPLC-DAD-MS was used to monitor changes in the composition of the samples. Copigmentation has been found to occur in all cases despite the low copigment/pigment molar ratio used, although the effect was different depending on the compound. Flavan-3-ols appeared as the less effective copigments, procyanidin B2 being even worse than monomeric flavanols, whereas flavonols behaved as the best ones. These latter copigments also induced the most statistically significant bathochromic shift in lambdamax. In the colorimetric analysis, it was observed that the lightness L* of the copigmented solutions increased with time, chroma C*ab decreased, and the hue hab increased. The copigments that produced a greater increase in the hue angle were the monomeric flavan-3-ols, which therefore showed to be the least protective cofactors against browning of the anthocyanin solution during the storage. With the time of storage, the formation of new pigments was observed in the solutions containing flavanols (xanthylium structures) and hydroxycinnamic acids (pyranoanthocyanins), which explains some of the color modifications produced in these solutions. Another relevant observation was that the stability of the anthocyanin was not much improved by most of the assayed copigments, since quite similar degradation rates were observed in the presence and absence of those cofactors.  相似文献   

10.
The so-called "yellow pigment" content of durum wheat has been used for a long time as an indicator of the color quality of durum wheat and pasta products. For decades the chemical nature of these pigments has been assigned to carotenoids, mainly to the xanthophyll lutein and its fatty acid esters. The chemical composition of the yellow pigments of eight German durum wheat cultivars was studied. Grains were milled on a laboratory mill. Pigment extraction of millstream fractions was performed according to the optimized ICC standard method 152 procedure, and the chemical composition of the extract was analyzed by isocratic reversed phase high-performance liquid chromatography. all-trans-Lutein ranged from 1.5 to 4 mg kg(-1), and zeaxanthin was found in traces. No lutein esters and carotenes were detected. Surprisingly, the fraction of carotenoids of the complete yellow pigment content amounted to only 30-50% of the yellow pigment quantities, so there are still compounds in durum wheat not yet identified that contribute considerably to the yellow color of the grain extracts. The isolation and chemical identification of those pigments are under investigation.  相似文献   

11.
Color and antioxidant properties of cyanidin-based anthocyanin pigments   总被引:1,自引:0,他引:1  
A series of cyanidin-based anthocyanin pigments was investigated to determine the effect of structural variation on a number of chemical and physical properties: CIELAB color coordinates, visual detection thresholds, hydration constants (pK(H)), and in vitro antioxidant activities (ORAC). In addition to individual isolated compounds, purified total pigment isolates from blackberry, elderberry, black carrot, red cabbage, and sweet potato were also examined. Acylation with cinnamic acids shifted color tonality (hue angle) to purple, and markedly increased pK(H) and antioxidant activity, but lowered the visual detection threshold. Glycosidic substitution at the 5 position moved tonalities toward purple and decreased pK(H), and tended to lower the ORAC value, but raised the visual detection threshold. Increasing the number of sugar substituents at the 3 position also affected all of these parameters, however, the extent was not predictable. Antioxidant levels of purified anthocyanin extracts were much higher than expected from anthocyanin content indicating synergistic effect of anthocyanin mixtures.  相似文献   

12.
Quantitative changes in the red and yellow carotenoid pigment fractions of four paprika oleoresins were studied at four storage temperatures. At all four temperatures, there was an overall loss of pigmentation, which was more marked with increasing temperature. However, pigmentation loss was not qualitatively uniform. At temperatures below 60 degrees C, the rate of destruction of the yellow pigment fraction was higher than that of the red pigments. Above 60 degrees C, the order of lability of the two fractions was inverted and the red pigment fraction became the more unstable. Thus, treatments above this temperature increase the proportion of yellow pigments. Any heat treatment results in a decrease in the total pigment concentration, with the initial proportion of red and yellow pigments switching in favor of one or the other depending on the temperature used.  相似文献   

13.
The effect of storage time on pH, titratable acidity, degrees Brix, organic acids, sugars, amino acids, and color of minimally processed cantaloupe melon (Cucumis melo L. var. reticulatus Naud. cv. Mission) was determined at 4 degrees C and 20 degrees C. Changes in most of the biochemical parameters with storage time were relatively slow at the lower temperature. At 20 degrees C, a 17% loss in soluble solids and a 2-fold increase in acidity occurred after 2 days. Organic acid content also increased considerably with time at this temperature as a result of the production of lactic acid. Oxalic, citric, malic, and succinic acids were the organic acids, and glucose, fructose, and sucrose were the sugars present in the freshly cut cantaloupe. Malic acid concentration decreased concurrently with lactic acid production indicating the possible involvement of anaerobic malo-lactic fermentation along with sugar utilization by lactic acid bacteria. The effect of storage on microbial growth was determined at 4, 10, and 20 degrees C. Gram-negative stained rods grew at a slower rate at 4 degrees C and 10 degrees C than the Gram-positive mesophilic bacteria that dominated microorganism growth at 20 degrees C. Eighteen amino acids were identified in fresh cantaloupe: aspartic acid, glutamic acid, asparagine, serine, glutamine, glycine, histidine, arginine, threonine, alanine, proline, tyrosine, valine, methionine, isoleucine, leucine, phenyl alanine, and lysine. The dominant amino acids were aspartic acid, glutamic acid, arginine, and alanine. Total amino acid content decreased rapidly at 20 degrees C, but only a slight decrease occurred at 4 degrees C after prolonged storage. Changes in lightness (L), chroma, and hue at both temperatures indicate the absence of browning reactions. The results indicate the potential use of lactic acid and lactic acid bacteria as quality control markers in minimally processed fruits.  相似文献   

14.
The commercial value of a cochineal (Dactylopius coccus Costa) sample is associated with its color quality. Because the cochineal is a legal food colorant, its color quality is generally understood as its pigment content. Simply put, the higher this content, the more valuable the sample is to the market. In an effort to devise a way to measure the color quality of a cochineal, the present study evaluates different parameters of color measurement such as chromatic attributes (L*, and a*), percentage of carminic acid, tint determination, and chromatographic profile of pigments. Tint determination did not achieve this objective because this parameter does not correlate with carminic acid content. On the other hand, carminic acid showed a highly significant correlation (r = - 0.922, p = 0.000) with L* values determined from powdered cochineal samples. The combination of the information from the spectrophotometric determination of carminic acid with that of the pigment profile acquired by liquid chromatography (LC) and the composition of the red and yellow pigment groups, also acquired by LC, enables greater accuracy in judging the quality of the final sample. As a result of this study, it was possible to achieve the separation of cochineal samples according to geographical origin using two statistical techniques: cluster analysis and principal component analysis.  相似文献   

15.
为明确彩色油菜花瓣色素成分和色素呈色机制,提高彩色油菜育种效率,本研究比较了红色、橙色、黄色和白色4种色系共10种彩色油菜花瓣色素代谢的次生代谢物含量,并采用液质联用仪(HPLC-MS/MS)分析红色、橙色和黄色油菜花瓣中花青素和类胡萝卜素含量,同时对花青素合成关键酶活性和编码关键酶活性的基因表达量进行分析。结果表明,各色系油菜花瓣积累了大量酚类和类黄酮化合物。红色系和橙色系油菜花瓣中含有丰富的原花青素和花色苷;黄色系油菜花瓣中不含原花青素,但含花色苷;白色系油菜花瓣既不合成原花青素,也不合成花色苷。红色和橙色油菜花瓣中的花色苷主要成分是矢车菊素和芍药素。红色、橙色、黄色和白色油菜花瓣中均含有胡萝卜素和番茄红素,且4种花色花瓣中的番茄红素含量均高于胡萝卜素。红色、橙色和黄色油菜花瓣的番茄红素含量仅为对应花色花瓣花青素的0.25%、0.15%、0.02%。基因表达分析结果表明,引起花青素在不同色系油菜花瓣中积累差异的基因为二氢黄酮醇还原酶基因(DFR)和花青素还原酶基因(ANS),在红色、橙色和橙黄色花瓣中DFRANS的表达量分别为黄色花瓣的100倍和1 000倍以上。相关性分析表明,彩色油菜DFRANS基因的表达量与花色苷含量呈高度正相关性。但是,DFR和ANS活性在红色、橙色、黄色和白色油菜花瓣中差异不显著。本研究为彩色油菜进行基因操纵中靶基因的选择和合理的育种线路提供了理论基础。  相似文献   

16.
The developmental patterns of carotenoids in Hamlin, Earlygold (an early-maturing selection), and Budd Blood sweet orange juices were studied during the September to mid-January period of the 1996-97 and 1997-98 seasons. The carotenoid concentration of Earlygold increased by as much as 4.9 times during the color development compared to 3.9 times in Hamlin and 4.5 times in Budd Blood juice in the same period. For the profiles of carotenoid pigment, dramatic changes occurred among the pigments that were present in high concentrations at the beginning of the season, with lutein and violaxanthin noted as the predominant pigments in Hamlin fruit. A marked increase in the percentage of beta-cryptoxanthin allowed it to become a major pigment in the late stage of maturation. The color development in the new cultivar Earlygold was especially notable, reaching the 36 color number, which is grade A, by late October to mid-November whereas Hamlin juice did not reach this grade A color number until January. Budd Blood juice was similar in carotenoid pigment content and seasonal changes to Hamlin juice, but also, the development of red anthocyanin pigment in January significantly increased juice color.  相似文献   

17.
Characterization of anthocyanins and flavonols and radical scavenging activity assays of extracts from four Chinese bayberry (Myrica rubra) varieties with different fruit colors were carried out. One dominant anthocyanin and three major flavonols were isolated by HPLC, and cyanidin-3-O-glucoside and two of three flavonols, myricetin and quercetin-3-O-rutinoside, were identified by cochromatography with authentic standards. Both DPPH* and ABTS*(+) cation assays indicated that the black varieties (Biji and Hunan) demonstrated much higher radical scavenging activities than the pink (Fenhong) and yellow (Shuijing) varieties, which may be attributed to much higher levels of anthocyanins, flavonoids, and total phenolics in the black varieties. Biji and Hunan had 6.49 and 6.52 mM Trolox equivalent antioxidant capacity (TEAC) per 100 g of fresh weight, whereas the pink (Fenhong) and yellow (Shuijing) bayberries had 1.32 and 1.31 mM TEAC/100 g. Different fruit color was reflected by the surface color and pigment extract color. Color stability of the pigment was dependent on pH, and the pigment was more stable at low pH (pH approximately 1.5). The lightness (L) increased while the chroma (C value) decreased with increase of pH until pH 5, but higher pH caused a small decrease for L and an increase for C.  相似文献   

18.
Thirty-seven apricot varieties, including four new releases (Rojo Pasión, Murciana, Selene, and Dorada) obtained from different crosses between apricot varieties and three traditional Spanish cultivars (Currot, Mauricio, and Búlida), were separated according to flesh color into four groups: white, yellow, light orange, and orange (mean hue angles in flesh were 88.1, 85.0, 77.6, and 72.4, respectively). Four phenolic compound groups, procyanidins, hydroxycinnamic acid derivatives, flavonols, and anthocyanins, were identified by HPLC-MS/MS and individually quantified using HPLC-DAD. Chlorogenic and neochlorogenic acids, procyanidins B1, B2, and B4, and some procyanidin trimers, quercetin 3-rutinoside, kaempferol 3-rhamnosyl-hexoside and quercetin 3-acetyl-hexoside, cyanidin 3-rutinoside, and 3-glucoside, were detected and quantified in the skin and flesh of the different cultivars. The total phenolics content, quantified as the addition of the individual compounds quantified by HPLC, ranged between 32.6 and 160.0 mg 100 g(-1) of edible tissue. No correlation between the flesh color and the phenolic content of the different cultivars was observed.  相似文献   

19.
We examined the antioxidant effects of paprika pigments on oxidation of linoleic acid and on decoloration of the sample when stored at 37 degrees C in the dark or exposed to fluorescent light for 8 h per day. (1)H nuclear magnetic resonance with dioxane as an external proton reference was used to estimate the oxidative deterioration of linoleic acid. Oxidation was estimated by observing the ratio of the divinylmethylene proton signal area in linoleic acid vs the proton signal area in dioxane. The addition of paprika pigments suppressed the oxidation of linoleic acid during storage in the dark, and the effect was markedly increased with increasing concentrations (0.02, 0.2, and 2%). When the linoleic acid with added paprika pigments was exposed to light, only a slight suppression of oxidation was observed, and the color of the sample disappeared more rapidly than that in the dark. At the time of decoloration of the sample with added pigments, considerable oxidation of linoleic acid occurred. As the color change is due to degradation of the pigment, an increase in oxidation at the time of discoloration is consistent with the pigments functioning as antioxidants. The addition of alpha-tocopherol to paprika pigments stabilized degradation of the pigments by light. Although the addition of alpha-tocopherol to linoleic acid with added paprika pigments prolonged the decoloration of the sample under light, the prevention of oxidation under the light condition was not as effective as for the samples stored in the dark.  相似文献   

20.
Four anthocyanin-pyruvic adducts were synthesized through the reaction of cyanidin 3-O-glucoside, cyanidin 3-O-rutinoside, cyanidin 3-O-sophoroside, and cyanidin 3-O-sambubioside with pyruvic acid, structurally characterized by liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR), and their chromatic properties were studied (pH and SO2 stability assays). Overall, these pigments were shown to have a higher resistance to discoloration toward pH variations and also in the presence of SO2, being that this resistance to discoloration was explained by a higher protection of the chromophore group against the water or bisulfite nucleophilic attack that gives rise to the colorless hemiacetal form. Only slight differences in the protection against the nucleophilic attack of water and bisulfite were found to occur between all of the cyanidin-pyruvic acid adducts studied. Indeed, anthocyanin-pyruvic acid adducts with glucose or sambubiose attached to the 3-O position of the flavylium moiety were shown to have smaller bleaching constants compared with similar pigments that possess a rutinosyl or sophorosyl moiety. The study of the pigments (A-D and cyanidin-3-O-glucoside) color parameters, namely, chroma (C), lightness (L), and the hue angle (h(a,b)), obtained from the CIELAB system, revealed that different patterns of sugars in the anthocyanin-pyruvic acid adduct moiety affected the referred three parameters of color. The loss of saturation (DeltaC < 0) and the increase of lightness (DeltaL > 0) presented by the cyanidin-pyruvic acid adduct solutions at acidic pH values (1.0 and 2.0) showed that they are much less colored than the cyanidin-3-O-glucoside. For higher pH values (5.0 and 7.0), the reverse trend was observed. This means that the cyanidin-pyruvic acid adducts A-D are much more colored than the anthocyanin at these pH values. The higher coloring capacity of these pigments at higher pH values may be an important feature, indicating a putative application of these compounds in food products.  相似文献   

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