Not-from-concentrate blueberry juice extraction utilizing frozen fruit, heated mash, and enzyme processes

Authors: STEIN-CHISHOLM, REBECCA - Louisiana State University; FINLEY, JOHN - Louisiana State University; LOSSO, JACK - Louisiana State University; Beaulieu, John

Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/5/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary: With the information obtained from this research, blueberry juice producers may better evaluate and streamline their juice processing practices based on selecting varieties and juice processing parameters. The advantage of freezing berries before pressing increases the window of juice production past the harvest season and allows for year round, value-added juice production. Research demonstrating that freezing does not affect the not-from-concentrate juice recovery is also important for local, small-scale producers to decide on which processing steps to take. Knowing how pressing temperature will affect the juice is also important for producers who are looking to create new or unique juice products. Producers can also use this information for estimating how many berries are needed to create specific amounts of juice. This is vital when juice processing plant equipment requires many liters of juice to run through all stages of processing, such as mash extraction, pressing, and filtration.

Technical Abstract: Juice production is a multibillion dollar industry and an economical way to use fruit past seasonal harvests. To evaluate how production steps influence not-from-concentrate (NFC) blueberry (Vaccinium sp.) juice recovery, bench top and pilot scale experiments were performed. In bench-top, southern highbush (SHB) blueberry (Vaccinium darrowii × Vaccinium corymbosum) and rabbiteye blueberry (RAB) (Vaccinium ashei) were pressed at varying temperatures. Press treatments included ambient temperature, frozen then thawed, and frozen then heated berries. In addition, two commercial pectinase enzymes were evaluated. Three batches were pressed and average juice recovery was calculated. The highest average free juice recovery (68.8% ± 1.1%) was attained by heating frozen berries and treating with enzyme. Comparing berry species pressed, SHB blueberries produced significantly more juice than RABs. There were no significant differences between enzymes used between berry species. Using this preliminary data, the optimum juice recovery method was then transferred to pilot scale processing. RABs were heated and treated with enzyme then pressed. Free juice recovery from the pilot scale was 74.0% ± 1.0%. Total juice recovery was calculated to be 87% ± 0.6%. With this information, further refinement of juice processes could increase juice production output for small-scale producers and expand local outlets for growers to market their crops as well as create new opportunities for growth in the fresh juice market segment.