Improvement of the nutritional value of cow milk with transgenic expression of recombinant human alpha-lactalbumin (alpha-LA) has been previously attempted. However, the detailed characterization of the recombinant protein and analysis of the transgenic milk components are not explored yet. Here, we first report production of healthy transgenic cows by somatic cell nuclear transfer, in which expression of up to 1.55 g/L of recombinant human alpha-LA was achieved. The recombinant human alpha-LA was purified from transgenic milk and displayed physicochemical properties similar to its natural counterpart with respect to molecular weight, structure, and regulatory activity for beta-1,4-galactosyltransferase. Additionally, no N-glycosylation was found in the recombinant human alpha-LA, whereas the endogenous bovine alpha-LA was glycosylated at the unusual site (71)Asn-Ile-(73)Cys. Compared with milk from nontransgenic cows, expression of the transgene did not materially alter milk composition, such as fat and protein content. Our research thus provides scientific evidence supporting the feasibility of humanizing cow milk.
Proanthocyanidins are a group of oligomeric or polymeric flavan-3-ols that are highly significant contributors to astringency in grapes and wines. An orthogonal L9(3) 4 test was adopted to determine the optimal extraction conditions and acid-catalysis cleavage of proanthocyanidins in the presence of excess phloroglucinol. The qualitative and quantitative analyses were done using HPLC-DAD-ESI-MS/MS. The results showed that the maximum extraction was obtained using 0.3 mol/L of HCl and 0.005 g of ascorbic acid with incubation at 70°C for 20 min. The precision and accuracy of this method were acceptable. The composition of free flavan-3-ols and proanthocyanidins in the skins of 'Marselan' grapes (Vitis vinifera L. cv.) was investigated. (-)-Epigallocatechin was found to be the most abundant free flavan-3-ol monomer and terminal subunits, whereas the extension subunits were mainly (-)-epicatechin-3-O-gallate in the early developmental stages, and primarily (-)-epigallocatechin and (-)-epicatechin in the middle and late stages.
Blueberries are rich in bioactive anthocyanins, which are associated with health benefits contributing to reducing the risk of diabetes and cardiovascular diseases. The objective of this study was to improve the yield of anthocyanins extracted from rabbiteye blueberry (Vaccinium ashei) fruits cultivated in Nanjing using ultrasound-assisted extraction and to identify the individual anthocyanins present in the extract. The extraction conditions of blueberry anthocyanins were optimized using response surface methodology. The Box–Behnken test was designed to investigate the effect of extraction using different ethanol concentrations, extraction time, and liquid-to-solid ratios. The optimum conditions of the extraction derived from the model were as follows: extraction time 24 h at 30°C using 72.50% ethanol which contains 0.02% v/v hydrochloric acid as a solvent and liquid-to-solid ratio 20 : 1 v/w. The extraction yield was 16.21 ± 0.44 mg/g under these optimum conditions. The 13 peaks of the anthocyanin extract from rabbiteye blueberry fruits in Nanjing were tentatively identified using high-performance liquid chromatography (HPLC) and high-performance liquid chromatography-electrospray ionization interface-mass spectrometer (HPLC-ESI-MS), which are the derivatives of delphinidin, cyanidin, petunidin, peonidin, and malvidin that were glycosylated by glucose, galactose, or arabinose. This research provides a reliable scientific basis for efficacious extraction and identification of anthocyanins from blueberry fruits, which would be helpful for further investigation of the function and application of blueberry anthocyanins extract to human health.
Background and Aims: Yan73 and Kolor are Vitis vinifera grape cultivars with both red skin and red pulp. The aim of the present work was to determine the distribution of flavonoid compounds in the skin, pulp and seed, as well as the aromatic composition of the whole berry. Methods and Results: Anthocyanin and flavonol were extracted from grape skin and pulp, while proanthocyanidin was isolated from skin, pulp and seeds; individual anthocyanins, flavonols and proanthocyanidins were then separated and determined by LC/MS. Anthocyanin was dominated by malvidin derivatives in the skin and by peonidin derivatives in the pulp. The distribution of flavonols in the skin and pulp of the two cultivars showed no consistent trend. Proanthocyanidins were unequally distributed in the skin, pulp and seeds. Proanthocyanidin content, composition and mean degree of polymerisation varied distinctly in the three tissues, especially the profile of the proanthocyanidin terminal and extension subunits. Yan73 and Kolor contained similar aroma compounds, both in free form and as glycosidically bound precursors, as determined by GC/MS, but their content varied significantly. Conclusions: Flavonoid compounds were asymmetrically distributed in the skin, pulp and seeds. Epicatechin was the common predominant extension subunit in the three tissues, while epigallocatechin, catechin and epicatechin-3-O-gallate were the characteristic extension subunits of the skin, pulp and seeds, respectively. Kolor accumulated more C6 aldehydes in the free fraction and more alcohols in bound fraction, while Yan73 was characterised by a higher content of terpenes. Significance of the Study: The results define the distribution of flavonoid compounds in two teinturier cultivars.
including (+)-catechin (C), (-)-epicatechin (EC) and (-)-epicatechin-3-O-gallate (ECG). With regard to the effect of training systems, M-VSP contributed to a significantly higher content of total flavan-3-ols, while the percentage of ECG was lower for M-VSP.As for the three flavan-3-ol units (terminal subunits, extension subunits and monomers), the 2012 vintage was more likely to accumulate extension subunits and monomers, and the effect of training system on these three flavan-3-ols units varied between the different vintages. Meanwhile, the proportion of ECG in terminal subunits and of C in extension subunits was higher in 2012, whereas the training system of F-TT had a higher percentage of ECG in extension subunits in both vintages. In addition, the effect of vintage on the composition of flavan-3-ols in harvested grape seeds was more obvious than that of the training system. INTRODUCTIONFlavan-3-ols are responsible for the organoleptic characteristics and biochemical properties of wine. Through the formation of complexes with salivary proteins, flavan-3-ols provide red wine with astringency and mouthfeel characteristics (Casassa & Harbertson, 2014). During wine ageing, flavan-3-ols can also take part in condensation reactions with anthocyanins to stabilise wine colour (Alcalde-Eon et al., 2006;Fulcrand et al., 2006). It is well known that moderate consumption of wine enhances its health benefits, and one of the most important contributors is flavan-3-ols. They possess a number of health-enhancing characteristics, like antioxidants and free radical scavengers, anti-carcinogenics, cardiopreventive and antimicrobial activities, and so on (Renaud & De Lorgeril, 1992;Aron & Kennedy, 2008).Among the phenolic compounds, flavan-3-ols are the most common group of flavonoids. The flavan-3-ols observed in grape seeds are mainly represented by (+)-catechin (C), (-)-epicatechin (EC) and (-)-epicatechin-3-O-gallate (ECG). Proanthocyanidins, as the polymers of flavan-3-ols, are composed of terminal and extension subunits analogous to the flavan-3-ols C, EC and ECG. Subunits are linked via interflavan bonds between C-4 and C-8, and less commonly between C-4 and C-6 (Haslam, 1998). The content and presence of flavan-3-ols in grape seeds depend mainly on variety, soil, climate and viticulture factors, among others. Furthermore, due to a great amount of extraction of flavan-3-ols from grape seeds during the red winemaking process (Sun et al., 1999), their eventual concentration and ability to act as astringents in red wine are affected correspondingly (Ough & Nagaoka, 1984;Morrison & Noble, 1990;González-Neves et al., 2002;Kemp et al., 2011). The extent of bitterness and astringency of wine depends largely on the composition of flavan-3-ols and the degree of polymerisation of proanthocyanidins. It has been reported that a higher proportion of ECG supplies wine with a coarse perception, while epigallocatechin (EGC) flavan-3-ol monomer, which is only found in skins, smooths the taste (Vidal et al., 2003). In addition, the extent...
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