Anthocyanins in strawberries

Anthocyanins were decolorized at pH 3.0 by the addition of sodinm sulfite at the C-2 or C-4 of the chromophore, a reaction that was rapidly reversible on acidification. Snlfnr dioxide, EDTA, and a combination of snlfnr dioxide and EDTA exerted very small effects on the losses of anthocyanins in strawberry pnrees and juices during 10 wk of storage at -20°C. Conversely, the addition of snlfnr dioxide and storage at 20°C slowed the anthocyanin losses and concnrrently decreased the formation of polymeric componnds, especially in pnrees. EDTA had a slight effect on color stability. ... 

Bridle, R and Garcia-Viguera, C., Analysis of anthocyanins in strawberries and elderberries a comparison of capiUary-1 electrophoresis and HRLC, Food Ghent., 59, 299, 1997. 

Polyphenoloxidase (PPO, EC 1.14.18.1) is one of the most studied oxidative enzymes because it is involved in the biosynthesis of melanins in animals and in the browning of plants. The enzyme seems to be almost universally distributed in animals, plants, fungi, and bacteria (Sanchez-Ferrer and others 1995) and catalyzes two different reactions in which molecular oxygen is involved the o-hydroxylation of monophenols to o-diphenols (monophenolase activity) and the subsequent oxidation of 0-diphenols to o-quinones (diphenolase activity). Several studies have reported that this enzyme is involved in the degradation of natural phenols with complex structures, such as anthocyanins in strawberries and flavanols present in tea leaves. Several polyphenols... 

One acetyl group was identified at position 6 in highbush blueberries, " plums, " red leaf lettuce," and all grapes (Table 4.3.2) and at position 4 in Eurya japonica berries. Although acetyls were found in anthocyanins from strawberries " " and purple mashua, the positions of this acyl group were not assigned. 

About 15 anthocyanins in bilberries (Vaccinium myrtillus L.) were reported by Ichiyanagi et al. using CZE separation and MS-NMR identification.Anthocyanin analysis of strawberry and elderberry extracts was performed by reverse HPLC at pH 1.8 and CZE using a standard silica capillary and pH 8.0 running buffer. Under these conditions, HPLC had more advantages than CZE in terms of anthocyanin separation in these extracts." ... 

Odriozola-Serrano I, Soliva-Fortuny R, Gimeno-Ano V and Martin-Belloso O. 2008a. Kinetic study of anthocyanins, vitamin C, and antioxidant capacity in strawberry juices treated by high-intensity pulsed electric fields. J Agric Food Chem 56 8387-8393. 

Two classes of dimeric anthocyanins isolated from plants (section 10.2.6) have been identified in plants for the first time. One class includes pigments where an anthocyanin and a flavone or flavonol are linked to each end of a dicarboxylic acyl unit. The other class includes four different catechins linked covalently to pelargonidin 3-glucoside. During the last decade, seven new desoxyanthocyanidins and a novel type of anthocyanidin called P)Tanoanthocyanidins have been reported (Section 10.2.2). Toward the end of the 20th century, several color-stable 4-substituted anthocyanins, pyranoanthocyanins, were discovered in small amounts in red wine and grape pomace.Recently, similar compounds have been isolated from extracts of petals of Rosa hybrida cv. M me Violet, scales of red onion, and strawberries. About 94% of the new anthocyanins in the period of this review are based on only six anthocyanidins (Table 10.2). 

Nakamura, M., Seki, M., and Furusaki, S., Enhanced anthocyanin methylation by growth limitation in strawberry suspension culture. Enzyme Microb. Technol, 22, 404, 1998. 

The antioxidant activity of anthocyanins in the fruits and leaves from different cultivars of the thornless blackberry (Rubus sp.), red raspberry (Rubus idaeus L.), black raspberry (Rubus occidentalis L.) and strawberry (Fragaria x ananassa D.) was reported [54]. Studies on the ability of endothelial cells (EC) to incorporate anthocyanins and on the potential benefits against various oxidative stressors showed that the enrichment of EC with elderberry anthocyanins gave significant protective effects in the endothelial cells against the oxidative stressors, hydrogen peroxide, 2,2/-azobis(2-amidinopropane) dihydrochloride, and iron(II) sulfate/ascorbic acid [55]. 

The dose response and metabolism of strawberry anthocyanins were examined with 12 healthy adults who had consumed each of three different doses of strawberry anthocyanin. The four main anthocyanins in pureed strawberries were pelargonidin 3-O-glucoside (94, 87.8%), cyanidin 3-0-glucoside (60, 7.7%), pelargonidin-3-rutinoside (4.5%), and pelargonidin-3-(6"-acetoyl)glucoside (trace) (Fig. 21). 

It has been known for decades that heat is one of the most destructive factors of anthocyanins in berry fruit juices (Jackman et al., 1987a). With strawberry preserves, it was shown as early as 1953 that the half-life time was 1 h at 100°C, 240 h at 38°C and 1300 h at 20°C. In a storage experiment with concentrates and dry powder of elderberry extracts, the stability increased 6-9 times when the temperature was reduced from 20°C to 4°C (Zajac et al., 1992). Anthocyanin degradation in anthocyanin solutions increased from 30% to 60% after 60 days when storage temperatures were increased from 10°C to 23°C (Cabrita et al., 2000). High-temperature short-time processing is recommended for maximum anthocyanin retention of foods containing anthocyanins (Jackman and Smith, 1996). 

Sato K, Nakayama M, Shigeta J (1996) Culturing conditions affecting the production of anthocyanin in suspended cell cultures of strawberry. Plant Sci 113 91-98. 

For this reason the basic coloring material, wherever extracted pigment was used, was the water-soluble portion of the ether-precipitated concentrate of the 1-butanol extract of strawberry juice (St B). This material has not been further purified by picration and crystallization. It contains essentially all the anthocyanin coloring pigments in strawberries free from the natural sugars. It was found, however, that the reactions of the water-soluble portion and the recrystallized material were not significantly different. 

Carbon dioxide-enriched atmospheres (10-20% CO2 in air) are used to extend the postharvest life of strawberries [162]. However, some adverse effects on colour, mainly a reduction in the intensity of red of the internal tissue, have been reported. Changes in strawberry anthocyanins and other polyphenols in response to carbon dioxide treatments have been studied [36]. The external and internal anthocyanin contents were significantly different in fruit stored in air compared with the initial values or with those of fruit stored under CO2 enriched atmosphere. No differences in the external anthocyanin content between fruit stored under C02-enriched atmospheres and freshly picked fruit were observed. However, there was a noticeable decrease in the internal anthocyanin content, particularly at 20... 

Apart from these, very few identifications of anthocyanins in foods seem to have been made, though some of those listed have since been confirmed. Thus Sondheimer and Kertesz (1948) have confirmed that the pigment of strawberries is pelargonidin monoglucoside. In Jonathan and Stayman Winesap apples the pigment has been identified as cyanidin-3-galactoside (Sando, 1937). 

Lopes-da-Silva, F., Pascual-Teresa, S., Rivas-Gonzalo, J., Santos-Buelga, C. Identification of anthocyanin pigments in strawberry (cv Camarosa) by LC using DAD and ESI-MS detection. Fur. Food Res. 

Bordonaba, J. G., Crespo, P., Terry, L. A. A new acetonitrile-free mobile phase for HPLC-DAD determination of individual anthocyanins in blackcurrant and strawberry fruits A comparison and validation study. FoodChem. 129,1265-1273,2011. 

Gil MI, Holcroft DM, Kader AA. Changes in strawberry anthocyanins and other polyphenols in response to carbon dioxide treatments. J Agric Food Chem 1997 45 1662-1667. 

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