Colour strawberries

Wilska-Jeszka, J. and Korzuchowska, A., Anthocyanins and chlorogenic acid copig-mentantion — Influence on the colour of strawberry and chokeberry juices, Z. Leb-ensm. Unters Forsch., 203, 38, 1996. 

Patras A, Brunton NP, DaPieve S and Butler F. 2009. Impact of high pressure processing on total antioxidant activity, phenolic, ascorbic acid, anthocyanin content and colour of strawberry and blackberry puree. Innov Food Sci Emerg Technol doi 10.1016/j.ifset.2008.12.004. 

Figure 6.6 Anthrocyanidins impart colour to many natural substances, such as strawberries and cherries. The choice of side chains can cause a huge change in the anthrocyanidin s colour. If the side chain is pH sensitive then the anthrocyanidin acts as an acid-base indicator structures of an anthrocyanidin at three pHs (red in high acidity and low pH, blue in low acidity and high pH and mauve in inter-midiate pHs)...

Torreggiani, D., Fomi, E., Guercilena, I., Maestrelli, A., Bertolo, G., Archer, G.P., Kennedy, C.J., Bone, S., Blond, G., Contreras-Lopez, E., and Champion, D. 1999a. Modification of glass transition temperature through carbohydrates additions Effect upon colour and anthocyanin pigment stability in frozen strawberry juices. Food Res. Int. 32, 441 146. 

Polyphenol oxidase Mushroom, grape, pear, kiwi, sago, tea, potato, strawberry, olive, beet, cocoa Enzymatic browning (pig-ments),ripening of fruits, flavour formation, colour e.g. strawberries) formation... 

Red beet gives a nice strawberry colour in ice cream, dairy products, fruit preps, jams and jellies as well as sugar confectionery products, which are not subjected to heavy heat treatment. It is a very intense colom and dosage levels are usually low. However, the pigment is susceptible to heat degradation and oxidation, which limits its use but can, in part, be overcome by adding the colom after heat treatment. Stability is highest at pH 4.5, and red beet colour is not recommended for alkaline applications. 

Anthocyanins occur widely in the red to blue coloured parts of plants Therefore, they can be found in several berry fruits, such as cherries and strawberries, in plums, eggplants, red cabbages, and radishes. For example, delphidin can be found in eggplant skins and grapes cyanidin in grapes, several species of stone fruits, raspberries, and strawberries ... 

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... 

Several authors have reported a stimulating effect of light on the postharvest colour development of non fully coloured berries [176]. The influence of postharvest light and temperature conditions on colour development in Kent strawberries has been described at two temperatimes 00 and 20 C) [177]. Colour development for white berries was greatest in the light, and at 20 C compared to 10 C, A pronounced stimulation of anthocyanin synthesis in light was observed for white and pink berries stored at 20 C and for red berries stored at 10°C. 

We can conclude that Trial 1 is creamier, with a redder colour and more of a strawberry taste. Trial 2 appears less creamy and more pear-flavoured. Trial 4 appears less sweet. 

The addition of 0.1-0.2% of sodium polyphosphates will stabilise the colour of strawberries, tomatoes, cherries, and so on, and the use of such compounds prior to canning or freezing will help keep vegetables green [52]. 

An isomer of citric acid is (1J ,2S)-1-hydroxypropan-1,2,3-tricarboxylic acid (8-67), also known as D-isocitric acid u-threo isomer), which is another intermediate of the citric acid cycle. This acid is the dominant acid in blackberries (Table 8.17) and occurs in other fruits in small or insignificant amounts (e.g. in apples). The isocitric acid content is one of the most important markers in the estimation of the proportion of fruit in coloured fruit mixtures, for example in mixtures of blackcurrants, strawberries and raspberries with apples. The concentration ratio of citric acid to isocitric acid is also employed for the detection of adulteration, and can reveal the addition of synthetic citric acid to optimise the taste of fruit drinks, especially in the case of added sugar. 

Anthocyanin with the structure of o-diphenols form complexes with metals (such as Al, K, Fe, Cu, Ca and Sn) that can stabilise the colour of products, but also may cause unwanted discolorations. For example, complexes with tin formed in cans may change the red colour of fruits (such as strawberries) to purple. 

BRS Magna (Ritschel et al., 2012) is also a result from the cross between BRS Riibea and lAC 1398-21. It is a teinturier grape with labrusca flavour. BRS Magna is a novel cultivar for juice and winemaking with an intermediate productive cycle and wide climatic adaptation. It is recommended to be grown in tropical and temperate climates. It exhibits the typical labrusca or strawberry flavour, resulting in a wine with intense red colour, proper alcoholic grade, and low level of acidity. 

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