Anthocyanins are a major group of plant pigments that have antioxidant activities. Pigments play a major role in human health and have attracted a lot of attention globally. Many factors affect anthocyanin yields, such as solvent type, incubation time, solvent-to-sample ratio, sample type, and temperature. The first parameter was tested, and the rest were considered constant in this experiment. A total of nine organic and water-based solvents (methanol and chloroform: methanol, acetone, ethanol, water) and their combinations were compared to extract anthocyanins from freshly-pureed strawberries. Solvents changed anthocyanin yield, color parameters, and profile. The color parameters of a* values lower than 30, L* values higher than 85, hue angle more than 40, and chroma less than 30 indicated some color degradation in strawberry anthocyanins. Therefore, the best solvents for anthocyanin assessment were methanol and methanol: water. The second-best solvent was the pH differential buffers. Other solvents such as ethanol, chloroform: methanol, water, and water-based solvents extracted considerable amounts of anthocyanins; however, they showed some degree of color degradation, evidenced by the color parameters. Acetone did not yield a stable extract which degraded over 48 h of storage at 4 °C. The extraction solvent determined the main anthocyanin of the anthocyanins profile. Pelargonidin was the major anthocyanin in chloroform: methanol solvent, while delphinidin was dominant in all other solvents.
Parameters such as titratable acids (TA), total soluble solids (TSS), and their ratio (TSS/TA) are critical in determining strawberry fruit quality and the value of new cultivars. Ten strawberry cultivars were evaluated in two environments (open field and high tunnel) in the city of Virginia Beach. The objective was to evaluate the fruit quality characteristics (total soluble solids, titratable acidity TA, and total anthocyanin content) of newer strawberry cultivars grown in the annual hill plasticulture systems in coastal Virginia climatic conditions. Another objective was to measure the correlation between TA and a new digital meter (pocket acidity meter; PAM). Fruits were harvested weekly and TSS was measured using a refractometer. Acidity was measured using the pocket acidity meter and titratable acidity by a single sample titrimeter. Genetics significantly affected total anthocyanin content, TSS, TA, and acidity. The effect of the environments (high tunnel and open field) was not significant on TSS but significant on total anthocyanin content, TA, and acidity. “Flavorfest” had the highest and “Sweet Ann” the lowest anthocyanin content, TSS, and TA among the cultivars. The acidity (PAM data) showed a different level of correlation than TA, with a higher correlation for the open field than the high tunnel. On average, when outliers were removed, there was a regression of TA = 2.22(PAM) + 0.49 between the two data sets, with R2 = 0.47.