Comprehensive analysis of the internal structure and firmness in American cranberry (Vaccinium macrocarpon L.) fruit

Authors: DIAZ-GARCIA, LUIS - University Of Wisconsin; RODRIGUEZ, LORRAINE - University Of Wisconsin; PHILLIPS, MATTHEW - University Of Wisconsin; LOPEZ-HERNANDEZ, ARNOLDO - University Of Wisconsin; GRYGLESKI, EDWARD - Valley Cranberries; ATUCHA, AMAYA - University Of Wisconsin; Zalapa, Juan

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/11/2019
Publication Date: 9/25/2019
Citation: Diaz-Garcia, L., Rodriguez-Bonilla, L., Phillips, M., Lopez-Hernandez, A., Grygleski, E., Atucha, A., Zalapa, J.E. 2019. Comprehensive analysis of the internal structure and firmness in American cranberry (Vaccinium macrocarpon L.) fruit. PLoS One. 14(9):e0222451. https://doi.org/10.1371/journal.pone.0222451.
DOI: https://doi.org/10.1371/journal.pone.0222451

Interpretive Summary: Cranberry fruit quality traits encompass many properties. Although visual appearance and fruit nutritional constitution have usually been the most important attributes, cranberry textural properties such as firmness have recently gained importance in the industry. Fruit firmness has become a quality standard due to the recent demand increase for sweetened and dried cranberries (SDC), which are currently the most profitable cranberry product. Traditionally, this trait has been measured by the cranberry industry using compression tests; however, it is poorly understood how fruit firmness is influenced by other characteristics. In this study, we developed a high-throughput computer-vision method to measure the internal structure of cranberry fruit, which may in turn influence cranberry fruit firmness. Our study highlights the potential use of internal structure and firmness data for breeding varieties with superior fruit quality. Finally, our method can be used as a decision-making tool for cranberry processing, especially to determine optimal harvesting timing and to ensure high quality fruit for different cranberry products. In particular, this study introduces a novel method to define key parameters useful for SDC production, which is currently the most profitable and in high demand cranberry product in the market.

Technical Abstract: Cranberry (Vaccinium macrocarpon L.) fruit quality traits encompass many properties. Although visual appearance and fruit nutritional constitution have usually been the most important attributes, cranberry textural properties such as firmness have recently gained importance in the industry. Fruit firmness has become a quality standard due to the recent demand increase for sweetened and dried cranberries (SDC), which are currently the most profitable cranberry product. Traditionally, this trait has been measured by the cranberry industry using compression tests; however, it is poorly understood how fruit firmness is influenced by other characteristics. In this study, we developed a high-throughput computer-vision method to measure the internal structure of cranberry fruit, which may in turn influence cranberry fruit firmness. The internal fruit structure of 16 cranberry cultivars was measured over a 40-days ripening period, representing more than 3000 individual fruit evaluated for 10 different traits. The internal structure data paired with fruit firmness values at each evaluation period allowed us to explore the correlations between firmness and internal morphological characteristics. Our study highlights the potential use of internal structure and firmness data as a decision-making tool for cranberry processing, especially to determine optimal harvesting timing and to ensure high quality fruit for different cranberry products. In particular, this study introduces a novel method to define key parameters useful for SDC production, which is currently the most profitable and in high demand cranberry product in the market.