分光光度法测定桑葚总花色苷含量的研究

测定果蔬中总花色苷含量的方法繁多。综合国内外各类相关研究资料,以桑葚果汁为实验原料,比较了直接分光光度法和pH示差分光光度法两种方法测定总花色苷含量的差异。结果表明:这两种方法用于总花色苷的测定都具有良好的线性相关性,且直接分光光度法操作简便,结果准确。     

Anthocyanin composition in aged Chilean Cabernet Sauvignon red wines

Anthocyanins in aged Cabernet Sauvignon red wines were studied by HPLC–MS. The major anthocyanin in 6, 7, and 8 year old red wine extracts was the dimer vitisin A produced by condensation of malvidin-3-O-glucoside mediated by pyruvic acid. In aged wine, the content of malvidin-3-O-glucoside decreased with age with a concomitant increase of vitisin A. The latter is accompanied by several condensation products with molecular weight up to 1500 m/z. Differential pulse voltammetry indicated that aged wines have lower antioxidant capacity than young wine (400 mV), but higher than malvidin-3-O-glucoside (483 mV). Tafel’s plots showed that the electrochemical process occurring in aged wines is different from young wines. Six, seven and eight year old wines show similar behaviour with plots of 234, 177 and 188 mV/dec, respectively. These values are higher than the expected 120 mV/dec corresponding to a first electronic transfer but smaller compared to the 523 mV/dec corresponding to young wine.     

Determination of anthocyanin content in C.V Monastrell grapes during ripening period using several procedures

The accumulation of anthocyanins in grape skin and their evolution during ripening were evaluated in Monastrell grapes grown at four different sites growing season. Of the different techniques used for this purpose, we used one chromatographic [high‐performance liquid chromatography (HPLC)] and three spectrophotometric (Saint‐Cricq, Fragoso‐García and Lamadon) methods. The grapes from two of the sites (Agüeros and Rubializas) presented much higher values of anthocyanin (1279 and 1207 mg kg^?1 respectively) compounds than the grapes from the other two sites. Of the different methods used, HPLC proved to be an invaluable tool for identifying and quantifying individual anthocyanins in a sample, while the Fragoso‐García technique was the best of the spectrophotometric methods for laboratories that do not have access to HPLC equipment. Application of principal component determination (PCA) to our experimental data resulted satisfactory classification of wines in terms of their geographical origin. High correlation coefficients were observed among the different spectrophotometric techniques (0.88 between Fragoso‐García and Saint Cricq; and 0.92 between Lamadon and Saint Cricq) and lower coefficients between HPLC and the spectrophotometric techniques.     

Phenolic composition of Merlot and Cabernet-Sauvignon grapes from Bordeaux vineyard for the 2009-vintage: Comparison to 2006, 2007 and 2008 vintages

Cabernet-Sauvignon and Merlot skin and seed extracts from Bordeaux grapes were investigated to determine both grape variety and vintage effect on phenolic composition. The total content of polyphenols and tannins in Merlot seeds was higher than that of Cabernet-Sauvignon allowing to discriminate the varieties. HPLC analyses underlined significant differences in the absolute concentration of proanthocyanidins amongst the two varieties and in their composition: mean degree of polymerisation (mDP) and percentage of galloylation of seed extracts were good indicators of grape variety. The vintage effect on the phenolic composition was confirmed for 2009 in comparison to previous vintages. Low values of mDP and concentrations of proanthocyanidins and anthocyanins were found in 2009 seeds and skins. The climatic conditions of 2009 (high rainfall before flowering followed by a strong hydric stress during berries development until ripening) let us hypothesise a lower activation of flavonoid pathway.     

Chemical characterisation of anthocyanins in tamarillo (Solanum betaceum Cav.) and Andes berry (Rubus glaucus Benth.) fruits

The anthocyanin composition of tamarillo (Solanum betaceum Cav., red variety) and Andes berry (Rubus glaucus Benth.) was determined by HPLC–PDA and HPLC–ESIMS. From the anthocyanin-rich extracts (AREs), pure compounds (1–7) were obtained by MLCCC (multilayer countercurrent chromatography) and further preparative HPLC, and their unequivocal structures were obtained by 1D and 2D NMR analyses. The new anthocyanin delphinidin 3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside-3′-O-β-d-glucopyranoside, as well as the known cyanidin-3-O-rutinoside, pelargonidin-3-O-rutinoside, and delphinidin-3-O-rutinoside were identified as constituents of tamarillo fruit. Although the anthocyanin composition of Andes berry had been reported before in the literature, the unequivocal structure elucidation of the major compound, cyanidin-3-O-α-l-rhamnopyranosyl-(1 → 6)-O-β-d-xylopyranosyl-(1 → 2)-β-d-glucopyranoside, was achieved for the first time.     

LED lighting and seasonality effects antioxidant properties of baby leaf lettuce

We report on the application of supplementary light-emitting diode (LED) lighting within a greenhouse for cultivation of red, green and light green leaf baby lettuces (Lactuca sativa L.) grown under natural illumination and high-pressure sodium (HPS) lamps (16-h; PPFD-170 μmol m⁻² s⁻¹) during different growing season. Supplementary lighting from blue 455/470 nm and green 505/530 nm LEDs was applied (16-h; PPFD-30 μmol m⁻² s⁻¹). Our results showed that to achieve solely a positive effect is complicated, because metabolism of antioxidant properties in lettuce depended on multicomponent exposure of variety, light quality or seasonality. The general trend of a greater positive effect of supplemental LED components on the vitamin C and tocopherol contents was in order: 535 > 505 > 455 > 470 nm; on the total phenol content: 505 > 535 = 470 > 455 nm; on the DPPH free-radical scavenging capacity: 535 = 470 > 505 > 455 nm; on the total anthocyanins: 505 > 455 > 470 > 535 nm. Further investigations are needed for understanding the mechanism and interaction between antioxidants and light signal transduction pathways.     

Preparation of novel distinct highly aromatic liquors using fruit distillates

This work describes the preparation of aromatised liquors using deodorised and concentrated fruit distillates. The raw spirits were improved by making a partial deodorisation, using activated charcoal, followed by concentration, using a distiller. The liquors were prepared by a maceration process. The procedure is exemplified using fig distillates to prepare myrtle berry liquors. The acidity, copper, polyphenol and anthocyanin indexes and volatile and anthocyanin profiles were monitored in each preparation step. The concentration process increased the ethanol proof to 75% v/v and decreased the acidity and the copper content. The partial deodorisation decreased the levels of high molecular weight volatiles, while the content of lower molecular weight compounds that contribute to flavour was maintained. Delphinidin‐3‐O‐glucoside, cyanidin‐3‐O‐glucoside, petunidin‐3‐O‐glucoside and malvidin‐3‐O‐glucoside were the major anthocyanins.     

Impact of edible coatings and packaging on quality of white asparagus (Asparagus officinalis, L.) during cold storage

The effects of edible coatings and plastic packaging on quality aspects of refrigerated white asparagus spears were studied using two different experimental protocols. The first included four coating formulations based on carboxymethyl-cellulose and sucrose fatty acid esters, whey protein isolate alone and in combination with stearic acid, and pullulan and sucrose fatty acid esters, and an uncoated sample serving as a control. The second set consisted of four treatments; uncoated asparagus spears (control), coated with a carboxymethyl-cellulose formulation, packaged in plastic packaging and combination of coated and packaged asparagus spears. All products were stored at 4 °C and the quality parameters such as weight loss, texture, visual appearance, lignin and anthocyanins concentration, and colour were evaluated during their storage. Edible coatings exhibited a beneficial impact on the quality of asparagus by retarding moisture loss, reducing hardening in their basal part and slowing down the purple colour development. The plastic packaging had a remarkable influence in reducing weight loss and retarding hardening but its impact to the rest of the quality parameters was similar to that of the edible coatings. The combination of packaging and edible coating did not seem to offer any additional advantage on asparagus spears apart from the fact that the product had a brighter appearance at the middle part of the stem compared to the packaged spears alone.     

花青素酰基化作用研究进展

花青素是一类非常重要的天然食用色素,酰基化花青素因其具有较高的稳定性而成为各国食品科学家的研究热点,本文介绍了酰基化花青素的植物来源、稳定机制以及花青素发展趋势。     

Colored and White Sectors From Star-Patterned Petunia Flowers Display Differential Resistance to Corn Earworm and Cabbage Looper Larvae

Anthocyanins are likely a visual aid that attract pollinators. However, there is also the possibility that anthocyanins are present in some flowers as defensive molecules that protect them from excess light, pathogens, or herbivores. In this study, resistance due to anthocyanins from commercial petunia flowers (Petunia hybrida) was examined for insecticide/antifeedant activity against corn earworm (CEW, Helicoverpa zea) and cabbage looper (CL, Trichoplusia ni). The petunia flowers studied contained a star pattern, with colored and white sectors. CEW larvae ate significantly less colored sectors than white sectors in no-choice bioassays in most cases. All CEW larvae feeding on blue sectors weighed significantly less after 2 days than larvae feeding on white sectors, which was negatively correlated with total anthocyanin levels. CL larvae ate less of blue sectors than white sectors, and blue sectors from one petunia cultivar caused significantly higher CL mortality than white sectors. Partially purified anthocyanin mixtures isolated from petunia flowers, when added to insect diet discs at approximately natural concentrations, reduced both CEW and CL larva weights compared to the controls. These studies demonstrate that the colored sectors of these petunia cultivars slow the development of these lepidopteran larvae and indicate that anthocyanins play some part in flower defense in petunia.