Decrease In Anthocyanin Content Research Articles

Effects of low-temperature acclimation on browning of litchi fruit in relation to shelf life

SummaryPostharvest pericarp browning of litchi fruit results in an accelerated loss in shelf life and reduced commercial value. Visual quality was lost in only 6.h at room temperature after fruit were removed from storage at 2°C, due to browning. Cultivar ‘Huaizhi’ fruit stored for 2 d at 8°C, for 26 d at 2°C, followed by 2 d storage at 15°C prior to a shelf-life evaluation at 23–258C, 80–90% r.h. were compared with continuous storage for 30 d at 2°C. Changes in polyphenol oxidase (PPO), anthocyanin, membrane leakage, colour, eating quality, total soluble solids, titratable acidity, and ascorbic acid were measured. The effects of temperature conditioning on disease incidence was also evaluated. Application of low-temperature acclimation delayed the decrease in anthocyanin content, the increases in PPO activity and membrane leakage, the changes in colour and eating quality, and partially inhibited decay of fruit. The results suggested that potential exists for shelf-life extension at ambient temperature when fruit are acclimated.

Comparison of periderm color and anthocyanins of four red potato varieties

The color, anthocyanin content per given surface area, and phenolics content of tuber periderm of four different varieties of red potatoes were compared. Three of the varieties, Norland, Red Norland, and Dark Red Norland, are members of a color sport family. Freshly harvested ‘Norland’ differed significantly in color, but not anthocyanin content per given surface area, from its sports. ‘Red Norland’ tubers were lighter in color than those of ‘Dark Red Norland’. In general, storage resulted in darkening of tubers and, except for the fourth variety, MN17922, a decrease in anthocyanin content per given surface area. Tubers from green-killed ‘Red Norland’ plants were more purplish-red than those from vine-killed plants. Stored tubers had greater periderm total phenolics content than freshly harvested tubers. The increase in periderm phenolics and decrease in anthocyanin content per given surface area may lead to darkening of tubers with storage. Cell walls connecting periderm to cortex tissue of ‘MN17922’ tubers were thinner than those in ‘Norland’ tubers, which may explain why it is realtively easy to separate the periderm of ‘MN17922’ from its cortex.

Changes in fruit quality in black chokeberry (Aronia melanocarpa) during maturation

SummaryBlack chokeberry fruits are rich in anthocyanins and can be used as a raw material for the production of natural food colourants. Fruit quality was studied during maturation in three true black chokeberry cultivars and in three cultivars derived through hybridization between chokeberry and rowans (Sorbus spp.). For each trait studied, the three black chokeberry cultivars were very similar. The three hybrid cultivars differed however from the black chokeberry cultivars for some traits in both timing and size of the response which indicates that cultivar selection for improvement of fruit quality can hardly be done among the true black chokeberry genotypes but may be efficient when the hybrid cultivars are also included. For the black chokeberry cultivars, maximum berry weight was reached already by the 22 August. Anthocyanin content increased by 180% during the period mid-August to mid-September. Meanwhile, the content of undesirable brown compounds increased by 100%. The content of malic acid remained unchanged whereas total acidity decreased in the initial part of the study period. Variation among sampling dates in total acidity was negatively correlated with variation in berry weight which suggests that dilution by water uptake affects total acidity. For the true black chokeberry cultivars, optimal harvest date was determined to be 8 September for this trial, when both mean berry weight and anthocyanin content had reached their maximum. By harvesting one week earlier browning was reduced by 32% but with a simultaneous decrease in anthocyanin content of 20%.

Changes in Strawberry Anthocyanins and Other Polyphenols in Response to Carbon Dioxide Treatments

Carbon dioxide-enriched atmospheres are used to reduce the incidence and severity of decay and to extend the postharvest life of strawberries. The influence of CO2 on the postharvest quality parameters of strawberries, particularly the stability of anthocyanins and other phenolic compounds, was investigated. Freshly harvested strawberries were placed in jars ventilated continuously with air or air enriched with 10%, 20%, or 40% CO2 at 5 °C for 10 days. Samples were taken initially, and after 5 and 10 days of storage, and color (L* a* b* color space), pH, TA, TSS, and firmness were measured. Anthocyanins and other phenolics were analyzed by HPLC. Elevated CO2 degraded internal color while air-treated fruit remained red. Internal and external tissues differed in composition and concentration of phenolic compounds. CO2 had a minimal effect on the anthocyanin content of external tissues but induced a remarkable decrease in anthocyanin content of internal tissues. Factors, such as pH and copigmentation, that could explain this degradation are discussed. Keywords: Fragaria × ananassa; controlled atmosphere; quality parameters; anthocyanins; phenolics

A note on the influence of acetaldehyde on colour of strawberry juice

AbstractAddition of acetaldehyde to strawberry juice caused an increase in colour density and decrease in anthocyanin content on storage. When both acetaldehyde and catechin were added, these changes were intensified. However, addition of catechin alone did not affect colour density. The results indicated that an increase in colour density required the simultaneous presence of anthocyanins, acetaldehyde and catechin. Big differences in colour measured by Hunter colorimeter were also obtained between strawberry juices with and without acetaldehyde.

Grape pigment phenomena: Interpretation of major colour losses during vinification

AbstractLarge decreases in colour density during the making of red wines, whether by the traditional fermentation on skins or by thermovinification, have not previously been explained in terms of juice and wine composition. The major colour loss is actually due to the extreme instability of deeply coloured pigment structures initially present in the juice extract to ethanol, whereas decrease in anthocyanin content is a minor contributing factor. The consequent decline in colour density during fermentation can be as much as five‐fold under conditions of high pH. Both red and blue chromophoric forms of the anthocyanins, in self‐association and co‐pigmentation with related flavonoid phenolics, are proposed as being present in the juice pigments. The stability of such complexes is ascribed to intermolecular hydrogen bonding forces. The existence of two nearly distinct phases in the accounting of total phenolics during ‘evolution ’of a red wine is emphasised.

The Effect of Acute Irradiation of Balsam Seeds(Impatiens balsamina L. ) on the Formation of Anthocyanins in Blossoms

V uvedené práci jsem sledovala nepřímý vliv záření na produkci antokyanů v květech červené balsaminyImpatiens balsamina L. Po 18 hodinách bubření byla semena ozářena dávkou 4560 r a sledovány změny v antokyanisaci květů. V X0 došlo u třech ze čtyř sledovaných linií průkaznému zvýšení obsahu antokyanů. 18 %, 18 % a 29 %. V X1 se kvantitativni obsah antokyanů bud vyrovnal s kontrolami nebo byl nižší, v X2 došlo průkaznému snízení obsahu antokyanů u všech sledovaných linii oproti kontrolám. Zřejmě se jedná o fysiologické ovlivnění typu „dlouhodobych vyznívajících modifikací“.V X1 se objevilo několik růzovych rostlin (3,4 %). Domnívám se, že nejde o vyštěpení následkem heterozygotního materiálu (u kontrol se nic takového neobjevilo), že však vlivem záření došlo recesivní mutaci, která se projevila až v X1.