263: Influence of Cultivar and Harvest Year on Strawberry Polyphenols

Introduction

Strawberries are a commonly consumed fruit rich in polyphenols, compounds known for their antioxidant properties and associated health benefits including improved cardiovascular and neurological health. The concentration of polyphenols in strawberries is influenced by genetic factors, environmental conditions, and agronomic practices. Therefore, the goal of this study was to quantify strawberry polyphenols in five cultivars harvested weekly across two growing seasons.

Methods

Strawberries were grown under controlled conditions in an experimental field in Virginia Beach, VA and harvested weekly across two consecutive growing seasons; a total of 44 samples were collected. Cultivars grown in the 2023 season included Honeoye, Flavorfest, Chandler, Ruby June, and Sweet Charlie, while the 2024 season included Chandler and Ruby June. Ripe strawberries were harvested, lyophilized, homogenized, and extracted using an acidified methanol-water solution. Extracted samples were characterized for total polyphenols via the Folin-Ciocalteu method (quantified as gallic acid equivalents (GAE)), total monomeric anthocyanins (TMA, quantified as cyanidin-3-O-glucoside equivalents (C3G)) via the pH differential method, and a total of 61 individual phenolics via LC-MS/MS.

Results

Total polyphenols in 2023 strawberries were: Chandler (19.42±0.92 mg GAE/g dw), Honeoye (18.25±2.13 mg GAE/g dw), Sweet Charlie (13.79±2.67 mg GAE/g dw), Ruby June (13.51±1.32 mg GAE/g dw), and Flavorfest (11.63±1.05 mg GAE/g dw). Interestingly, total phenolic content was consistent throughout the harvest season (10.56% RSD), while TMA varied widely (39.48% RSD). In 2024, one high and one low polyphenol cultivar (Chandler and Ruby June, respectively) were analyzed, with total polyphenols again being higher in Chandler (24.46±3.18 mg GAE/g dw) than Ruby June (16.70±1.97 mg GAE/g dw). Both Chandler and Ruby June were higher in total polyphenols and lower in TMA in 2024 compared to 2023. Regarding individual phenolics, pelargonidin-3-O-glucoside, catechins, and phenolic acids were most abundant across all cultivars.

Significance

These results highlight differences among cultivars and harvest years on strawberry polyphenols and can be used by growers to prioritize cultivation of high polyphenol cultivars like Chandler. High polyphenol varieties can be marketed to health-conscious consumers for their high antioxidant content, providing health benefits to consumers and economic benefits to growers.

Authors: Molly E Caron, Michael J McLeod Jr, Virginia B VanHook, Alicia A Surratt, Patricia Richardson, Jayesh Samtani, Dennis P Cladis