Color and anthocyanin composition of strawberry fruit: Changes during fruit development and differences among cultivars, with special reference to the occurrence of pelargonidin 3- malonylglucoside

Changes in concentration and composition of anthocyanins during color development in fruit of strawberry (Fragaria X ananassa Duch.) were determined, using a pelargonidin 3-malonylglucoside (PMG)-producing cultivar 'Nyoho'. Color parameters of fruit appearance (L*: lightness, H°: hue angle and C*: chroma) reached their minimum (L* and H°) or maximum (C*) levels at 41 days after anthesis, while the concentration of total anthocyanins continued to increase. Anthocyanins may accumulate in the inner part of a receptacle at a later stage of fruit maturation. Although the relative percentage of cyanidin 3- glucoside (CG) was high at the early stage of color development, the percentage of PMG was relatively constant throughout coloring period. The occurrence or absence of PMG in strawberry cultivars can be determined readily. A further analysis was conducted to determine the occurrence of PMG in 20 Japanese cultivars. Pelargonidin 3-glucoside (PG) was the predominant pigment (66-94% of total anthocyanins), while PMG (5-24% of total anthocyanins) was detected in 11 cultivars. However, there was no significant difference in color parameters and the concentration of total anthocyanins between the groups of PMG-producing and - lacking cultivars. There were significant linear relationships between the concentration of total anthocyanins, and L* and H°, and also between the relative percentage of CG and L*. Within cultivars lacking PMG, there was a negative relationship between the relative percentage of PG and H°, but a positive one within Cultivars producing PMG. Therefore, the occurrence or absence of PMG may play a negligible role in color development, but a balance of three major anthocyanins may affect color appearance of strawberries.