Improving Susutainability of Aronia Berry Industry: Fruit Quality Evaluation and Value-Added Processing

Rui Huang, University of Nebraska-Lincoln

Copyright 2023, Rui Huang

Abstract

Aronia berry has been attracting interest due to health benefits. However, aronia industry lacks integrated research to help improve the sustainability. Current aronia industry is facing many challenges, like lack of knowledge on growing high quality aronia berry, producing consumer-acceptable aronia products, and valorizing aronia by-products. Therefore, we firstly evaluated the association between aronia berry quality and pre-harvest factors. Results showed late harvest (two weeks) significantly increased the °Brix: acid of aronia juice. Comparing berries grown in the Midwest and Northeast, most quality related indicators of aronia juice were not significantly different except two minor volatiles. Correlations with meteorological factors varied, being significant with all the analyzed physicochemical indicators and most volatiles, but not significant with health-promoting indicators. We secondly identified the key astringent compounds in aronia juice. Results showed proanthocyanidins were validated as the key astringent compounds, linked by B-type bonds, with (-)-epicatechin as the extension and predominantly the terminal units, having a 69.56 mDP. We thirdly improved the palatability of aronia juice and evaluated the storage stability. Results showed modifications with egg white solids or gum Arabic significantly reduced the astringency intensity and enhanced the consumer liking of aronia juice (P < 0.01). When products were treated by high-pressure processing and stored at 4 C for 12 months, no microbial safety concern occurred. Besides, two modifications significantly enhanced the physical and color stability of aronia juice. The shelf life was at least 6 months, while a longer storage to 12 months resulted in the loss of flavor and color. We fourthly valorized aronia pomace. Results showed pressure-cooking for 30-40 min significantly increased the extractable and aqueous phase releasable phenolics especially proanthocyanidins and improved the dietary fiber profile of aronia pomace. Pressure-cooking for aronia pomace increased releasable phenolics during digestion, retained more phenolics and stronger antioxidant capacity after dialysis, and promoted higher production of short chain fatty acids during fermentation, especially acetate. Overall, this dissertation can help aronia growers and processors obtain and retain a sustainable industry.