Anthocyanin Degradation in Detached Pome Fruit with Reference to Preharvest Red Color Loss and Pigmentation Patterns of Blushed and Fully Red Pears

Abstract

<jats:p>Exposed fruit of `Rosemarie' blushed pear (<jats:italic>Pyrus communis</jats:italic> L.) displayed daily fluctuations in color in response to temperature while color was more stable in other blushed and fully red cultivars. `Rosemarie' pears increased in redness with the passing of cold fronts, but rapidly lost red color during intermittent warmer periods. Studies on anthocyanin degradation in detached apples and pears indicated that preharvest red color loss was due to net anthocyanin degradation at high temperatures. In support, anthocyanin degradation in attached `Rosemarie' pears corresponded with a warm period during fruit development. Susceptibility to color loss was dependent on the ability of fruit to accumulate anthocyanin. This is due to an exponential relationship between anthocyanin concentration and hue at high pigment levels and a linear relationship at lower pigment levels. Blushed and red pear cultivars that accumulate more anthocyanin with lesser dependence on climatic conditions were less susceptible to fluctuation in color.</jats:p>

Anthocyanin biosynthesis in pears is regulated by a R2R3-MYB transcription factor PyMYB10

“…In pear skin, red color fades toward harvest (Steyn et al 2004b), which is not common in other fruits such as apple (with higher anthocyanin content toward harvest), suggesting that anthocyanin synthesis in pear has unique features. In this study, the transcription of PyMYB10 and anthocyanin biosynthetic genes declined during late stages of fruit development, in agreement with the lower eYciency of anthocyanin synthesis.…”

“…However, anthocyanin biosynthesis and accumulation in pears appears to be more complicated. For example, the red skin apparently fades toward harvest (Steyn et al 2004b), and anthocyanin content decreases under strong light (Steyn et al 2004b). Evidence of the involvement of MYB, bHLH or other TFs in anthocyanin biosynthesis is largely lacking in pears, and whether these genes are induced by sunlight remains unknown.…”

Increased accumulation and decreased catabolism of anthocyanins in red grape cell suspension culture following magnesium treatment

“…For example, pulse-chase experiments with softened Cabernet Sauvignon berries demonstrated increased anthocyanin catabolism in parallel to decreased synthesis when growth temperatures were elevated, suggesting that both processes determine the final color of the grapes (Mori et al 2007). Similarly, loss of red pigmentation in pears and apples at elevated temperatures or decreased light intensities is a combination of less synthesis and increased catabolism (Huysamer 1998;Steyn et al 2004). Similar to observations in detached Cabernet Sauvignon grapes (Mori et al 2007), anthocyanin turnover was found in the cell suspension of V. vinifera cv.…”

“…Understanding anthocyanin catabolism in fruit might enable its inhibition, leading to a significant increase in pigment accumulation in the plant tissues. Inhibition of anthocyanin degradation in fruit could be most valuable at elevated temperatures, during which there is an increase in the rate of pigment degradation (Huysamer 1998;Mori et al 2007;Steyn et al 2004).…”

Nanoreinforced alginate–acerola puree coatings on acerola fruits

“…Although the puree used for the coatings exhibited a bright red color, acerola purees (and consequently the puree-based coatings) are highly susceptible to color fading, because of anthocyanin degradation during processing and storage (Bakowska et al, 2003), which results in color changes (Steyn et al, 2004). Indeed, the brownish pale-red color of AA-and CWAA-coated acerolas indicates loss of saturation and partial conversion of flavylium cation of the anthocyanins into colorless forms (De Rosso and Mercadante, 2007;Rodríguez-Saona et al, 1999), which explains why they were less accepted.…”