Preliminary Report on Jujube Fruit Cold Storage and Nutrient Changes

Jujubes belong to the Rhamnaceae family and have a high vitamin C content. More and more people are interested in growing and consuming jujubes in the United States. The bottlenecks now are limited cultivars and research support. Jujube fruit storage and processing information is very limited in the U.S. In 2014, a preliminary cold storage study was conducted with cultivars Li and Sherwood in a walk-in cooler at New Mexico State University Sustainable Agriculture Sciences Center at Alcalde, NM. Quart sized zip lock bags with punched holes were used. With limited fruit supplies, we only tested one maturity stage for each cultivar: 20-30% red/brown color for mid-season cultivar Li and 15-25% red/brown color for late season cultivar Sherwood. ‘Li’ with 20-30% red color could be stored for 3-4 weeks while ‘Sherwood’ with 15-25% red color were kept well for 8-10 weeks with marketable quality at temperatures of 0-4 °C. As cold storage proceeded, jujube fruit started to have more red/brown color and pitting after four weeks for ‘Li’ and eight weeks for ‘Sherwood’. Fruit turned soft but was not rotten. ‘Sherwood’ had higher vitamin C content (428 mg/100g fresh weight) than ‘Li’ (329 mg/100g fresh weight). Fruit vitamin C content kept constant and dropped slightly at later stage of storage. ‘Li’ retained 90% of its original vitamin C content after six weeks of cold storage while ‘Sherwood’ still retained 90% of its original vitamin C content after 10 weeks of storage. Fruit sugar content stayed constant and increased slightly for ‘Li’ at week six. For ‘Sherwood’, the total sugar content remained constant during the 10-week storage period, but after week six, sucrose content decreased while glucose and fructose increased. Though there are more questions than answers for jujube cold storage, the results from this preliminary study are promising. As more late-maturing cultivars become available, and with more accurate temperature control, it could be possible to store jujube fruit for two months or longer, which will give growers more marketing choices.