Influence of Heat, Cultivar and Maturity on the Anthocyanidin—3,5—diglucosides of Muscadine Grapes

Abstract

In order to assess the effects of heat, cultivar and maturity upon muscadine grape anthocyanins (Acys), the Acys were extracted from heated muscadine juices, from 11 cultivars of muscadines, and from muscadines separated into levels of maturity. Individual Acys were separated by thin-layer chromatography (TLC) and quantitated by densitometry. Heating resulted in relative increases in the 3,5-diglucosides of cyanidin (Cy), malvidin (Mv) and peonidin (Pn) at the sacrifice of delphinidin (Dp) and petunidin (Pt)-3,5-diglucosides. Except for an initial sharp loss of Mv, Dp degraded most rapidly with heating followed by Pt, Cy, Mv, and Pn. Total Acys in the 11 cultivars ranged from 40 to 403 mg/lOOg fruit with wide variations in the relative contents of individual Acys. Dp was usually the most prevalent Acy in the pigment complex followed by Cy or Pt, Pn and Mv. Cultivars with relatively high Mv and total Acys contents yielded juices and jellies with the highest quality and most stable colors. Harvest date influenced relative percentages of Pn, Mv, and Dp. Maturity level influenced the relative percentage of Mv and concentrations of all Acys.

Identification of anthocyanins in muscadine grapes with HPLC-ESI-MS

“…According to the study by Wu and Prior (2005a), if an anthocyanin contains two hexoses, the two hexoses will be likely linked to different positions of anthocyanidin, most likely at the 3-and 5-positions. Previous studies also suggested that the sugar moieties linked to anthocyanins in muscadine grapes are primarily glucose and in non-acylated form (Flora, 1978;Goldy, Ballinger, & Maness, 1986). Therefore, the anthocyanins found in present study were tentatively identified in 3,5-diglucoside form.…”

Flavor and Color of Fruits as Affected by Processing

“…Juices from muscadine cultivars containing higher total anthocyan ins and higher percentages of malvidin glycosides are more stable to heat preservation (Flora 1978). Low-temperature storage and S02 treatment provide the best protection for muscadine products (Flora and Nakayama 1981).…”

Application of muscadine grape (Vitis rotundifolia Michx.) pomace extract to reduce carcinogenic acrylamide

“…Also, unique to muscadine grapes is the presence of myricetin in the bronze grapes, as this flavonol is not present in white V. vinifera L. grapes (Flora, 1978). Another unique attribute of muscadine fruit chemistry is the presence of anthocyanins, such as 3,5-diglucosides of delphinidin, cyanidin, petunidin, peonidin and malvidin, in non-acylated forms (Flora, 1978).…”