Meta-analysis of apple (Malus x domestica Borkh.) fruit and juice quality traits for potential use in hard cider production

Authors: Gottschalk, Christopher; VANDERWEIDE, JOSHUA - University Of British Columbia; VAN NOCKER, STEVE - Michigan State University

Submitted to: Plants, People, Planet
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2022
Publication Date: 4/10/2022
Citation: Gottschalk, C.C., Vanderweide, J., Van Nocker, S. 2022. Meta-analysis of apple (Malus x domestica Borkh.) fruit and juice quality traits for potential use in hard cider production. Plants, People, Planet. 3.10262. https://doi.org/10.1002/ppp3.10262.
DOI: https://doi.org/10.1002/ppp3.10262

Interpretive Summary: In this study, we aimed to analyze and document the variation in the content of sugar, acidic, and bitter compounds in apple by collecting previously published and non-published data. We found data on sugar, acidity, and bitter compounds for over 800 unique apple varieties, which exhibited a wide range in values for those three traits. Most apple varieties we analyzed were categorized into groups that are described as being sweet or acidic. Apple varieties with bitterness, a desirable quality for the production of hard cider, were less common. Lastly, we compared the classifications of a subset of apple varieties from the same sources across growing seasons, revealing that acidic and bitter apples (desirable for hard cider) are prone to changes in their contents in response to the season. This result supports the idea of “vintage” quality for cider produced from these apples, which can be utilized as a marketing tactic for hard cider producers.

Technical Abstract: The North American fermented beverage market has undergone extensive growth in the fermented apple juice (hard cider) sector over the last decade. Traditional hard cider producing regions such as England, France, and Spain have historically utilized cider-specific apples that have desirable balances between sugar, organic acid, and phenolics. However, in North America, culinary apples (lower acidity and phenolics) are predominantly used, and information distinguishing the varieties with novel use for hard cider production is lacking. In this study, we evaluated variation of four major apple biochemical traits (total soluble solids, pH, titratable acidity, and total phenolics) as they relate to use for hard cider production by using a meta-analysis approach. We analyzed the variation in cider quality traits across 47 published works and more than 800 unique apple varieties, including an additional analysis of 142 varieties from cider apple germplasms in the United States. The biochemical traits of many varieties exhibited plasticity, and the characterization of a subset of varieties using two cider classification system revealed that most belonged to the “sweet” or “sharp”(acidic) categories rather than“bitter”(high phenolic content). We also compared the classification of a subset of varieties from two US germplasm resources across two seasons and found varieties that have high percent phenolics and/or malic acid experienced greater biochemi-cal plasticity and potential classification change across vintages. Ultimately, this work provides information regarding the variability in apple bio-chemical traits and also suggests a unique opportunity for producers to market “vintage” quality.