Impact of ultrasonication applications on color profile of foods

Food color is a feature that provides preliminary information about their preference or consumption. There are dominant pigments that determine the color of each food; the most important pigments are anthocyanins (red–purple color), chlorophylls (green color), carotenoids (yellow-orange color), and betalains (red color). These pigments can be easily affected by temperature, light, oxygen, or pH, thereby altering their properties. Therefore, while processing, it is necessary to prevent the deterioration of these pigments to the maximum possible extent. Ultrasonication, which is one of the emerging non-thermal methods, has multidimensional applications in the food industry. The present review collates information on various aspects of ultrasonication technology, its mechanism of action, influencing factors, and the competence of different ultrasonication applications (drying, irradiation, extraction, pasteurization, cooking, tempering, etc.) in preserving the color of food. It was concluded that ultrasonication treatments provide low-temperature processing at a short time, which positively influences the color properties. However, selecting optimum ultrasonic processing conditions (frequency, power, time, etc.) is crucial for each food to obtain the best color. The key challenges and limitations of the technique and possible future applications are also covered in the paper, serving as a touchstone for further research in this area.     

Principal components of phenolics to characterize red Vinho Verde grapes: Anthocyanins or non-coloured compounds?

Phenolic profile of 10 different varieties of red “Vinho Verde” grapes (Azal Tinto, Borraçal, Brancelho, Doçal, Espadeiro, Padeiro de Basto, Pedral, Rabo de ovelha, Verdelho and Vinhão), from Minho (Portugal) were studied. Nine Flavonols, four phenolic acids, three flavan-3-ols, one stilben and eight anthocyanins were determined. Malvidin-3-O-glucoside was the most abundant anthocyanin while the main non-coloured compound was much more heterogeneous: catechin, epicatechin, myricetin-3-O-glucoside, quercetin-3-O-glucoside or syringetin-3-O-glucoside. Anthocyanin contents ranged from 42 to 97%. Principal component analysis (PCA) was applied to analyse the date and study the relations between the samples and their phenolic profiles. Anthocyanin profile proved to be a good marker to characterize the varieties even considering different origin and harvest. “Vinhão” grapes showed anthocyanins levels until twenty four times higher than the rest of the samples, with 97% of these compounds.     

Differentiation of young red wines based on cultivar and geographical origin with application of chemometrics of principal polyphenolic constituents

Nineteen major polyphenolic phytochemicals including hydroxycinnamate derivatives, flavanols, flavonols, and anthocyanins, were determined in 40 experimental red wines employing HPLC-DAD. All wines analysed were young (non-aged), produced, and stored under identical conditions, in an effort to minimize the effect of oak wood and vinification technology. The data obtained from this examination composed the matrix for the implementation of chemometrics, which aimed at differentiating the wine samples on the basis of cultivar and geographical region of origin. Discriminant analysis performed at a 95% significance level revealed a very satisfactory categorization of the samples both in terms of cultivar and region of origin, thus illustrating the validity of major phenolic phytochemicals for studies pertaining to wine quality and authenticity.     

Direct characterization of aqueous extract of Hibiscus sabdariffa using HPLC with diode array detection coupled to ESI and ion trap MS

The phenolic fraction and other polar compounds of the Hibiscus sabdariffa were separated and identified by HPLC with diode array detection coupled to electrospray TOF and IT tandem MS (DAD‐HPLC‐ESI‐TOF‐MS and IT‐MS). The H. sabdariffa aqueous extract was filtered and directly injected into the LC system. The analysis of the compounds was carried out by RP HPLC coupled to DAD and TOF‐MS in order to obtain molecular formula and exact mass. Posterior analyses with IT‐MS were performed and the fragmentation pattern and confirmation of the structures were achieved. The H. sabdariffa samples were successfully analyzed in positive and negative ionization modes with two optimized linear gradients. In positive mode, the two most representative anthocyanins and other compounds were identified whereas the phenolic fraction, hydroxycitric acid and its lactone were identified using the negative ionization mode.     

葡萄花色甙优化提取和纯化工艺研究

本文用正交实验对经发酵的玫瑰香葡萄皮渣的总色素、食用色素的优化提取工艺进行了研究，同时对粗色素的纯化工艺进行了探索。     

Redox Behavior of Anthocyanins Present in Vitis vinifera L.

Voltammetric techniques were employed to study the electrochemical behavior of several anthocyanins. The redox behavior of anthocyanins with the same basic structure, the influence of glycosylation on the redox behavior of anthocyanins derived from different anthocyanidins, and the influence of methoxylation were investigated. The anthocyanins used in this study were malvidin‐3‐O‐glucoside chloride, malvidin‐3,5‐di‐O‐glucoside chloride, cyanidin‐3‐O‐glucoside chloride, cyanidin‐3,5‐di‐O‐glucoside chloride, peonidin‐3‐O‐glucoside chloride, delphinidin‐3‐O‐glucoside chloride and the anthocyanidin petunidin chloride, all of them present in Vitis vinifera L. All hydroxyl groups of the anthocyanins can be electrochemically oxidized and the anthocyanins studied revealed a complex and pH dependent oxidation process, with the occurrence of adsorption and of oxidation products blocking the electrode surface.     

The Chemistry of Rose Pigments

In this article we present a survey of the pigments found in the flowers and fruits of old and modern varieties of roses. The yellow colors are produced by carotenoids, the reds by anthocyanins, and the modern oranges by a mixture of the two. The great structural diversity of the carotenoids contrasts with a surprisingly small number of anthocyanins. For the carotenoids found in roses, a clear correspondence exists between the structure and the breeding partners used; the old yellow roses, which arose from crosses with Chinese varieties, mainly contain carotenoids from early stages in the biosynthesis, while in the modern yellow roses, which are descended from Central Asian foetida types, hydroxylations, epoxidations, and epoxide transformations readily occur. A recently elucidated carotenoid degradation sequence follows the scheme C₄₀ → C₁₃ + C₂₇ → C₁₃ + C₁₄. The C₁₃ compounds are odoriferous substances that contribute to the scent of roses. In the physiological pH region, copigmentation with flavonol glycosides is crucial for stabilization of the anthocyanin chromophores. Many roses, including the “apothecary's rose”, which was once used medicinally, contain large amounts of strongly astringent ellagitannins, monosaccharide esters of gallic acid.     

Determination of Anthocyanins and Flavonols in Paeonia delavayi by High-Performance Liquid Chromatography with Diode Array and Mass Spectrometric Detection

The colors of the leaves in Paeonia delavayi may be pure green, green-red, or dark red according to their habitat. The goal of this study was to compare the type and the total concentrations of anthocyanins and flavonols in red and green P. delavayi. The constituents and concentration of anthocyanins and flavonols were identified and determined by high-performance liquid chromatography with diode array detection and mass spectrometry. Cyanidin-3, 5-di-O-glucoside, cyanidin-3-O-glucoside, and peonidin-3-O-glucoside were first determined in red P. delavayi. There were no anthocyanins in green P. delavayi. Seven flavonols were identified in both red and green P. delavayi with differences in their concentrations. The concentrations of total anthocyanins and flavonoids were determined at 525 and 360?nm using the external standard method. The total anthocyanins in red P. delavayi were 152.24?mg/100?g in leaves and 78.92?mg/100?g in stems. The total flavonoids were 805.4?mg/100?g in leaves and 438.3?mg/100?g in stems, which were much higher than in green P. delavayi for both leaves and stems. This study reports composition and concentration differences in red and green P. delavayi based on ecological habitat.     

Three-way chemometric method study and UV-Vis absorbance for the study of simultaneous degradation of anthocyanins in flowers of the Hibiscus rosa-sinensys species

Ultraviolet-visible spectra of flower extracts of the Hibiscus rosa-sinensys L. var. regius maximus species have been measured between 240.02 and 747.97 nm at pH values ranging from 1.1 to 13.0. Deconvolution of these spectra using the Parallel Factor Analysis (PARAFAC) model permitted the study of anthocyanin systems without isolation and purification of the individual species. Seven species were identified: flavilium cation, carbinol, quinoidal base, and E and Z-chacone and their ionized forms. The concentration changes of flavilium cation, quinoidal basen, and E and Z ionized chalcones were determined as function of pH at the different wavelengths. The flavilium cation, quinoidal base, and ionized E-clacone are involved in tho stage kinetic processes, a fast one followed by a slower one. Ionized Z-chalcone obeys a simple first-order processes. The spectral profiles recovered by PARAFAC model are in excellent agreement with bands of experimental spectra reported in the literature for the individual species measured at specific pH values. These results complement those obtained using chemical and simple mathematical techniques and demonstrate how chemometric methods can resolve problems for complex systems.