Extending the life of fresh cranberries

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Photo by Keith Weller.

Cranberries are tart, tiny fruits packed with powerful antioxidants. The small, red berries offer a wide variety of health benefits. Not only are cranberries a healthy, low-calorie snack, but they can also play a significant role in preventing urinary tract infections, reducing the risk of gum disease and much more. In fact, studies show that the significant amounts of antioxidants in cranberries may help protect against heart disease, cancer, and other diseases. The good news about cranberries is spreading, resulting in growing consumer demand for fresh cranberries and cranberry products. This demand has led to increased interest in finding ways to extend the shelf life of the popular fruit. Setting out to determine the optimum conditions for storing fresh cranberries, Charles F. Forney. a research scientist in Postharvest Physiology at the Atlantic Food and Horticulture Research Centre in Nova Scotia, Canada, conducted a study of fresh cranberries and their postharvest life. Forney's study was published in the April 2008 issue of HortScience.

The research study was conducted over three seasons to determine the relationship of temperature and humidity on fresh cranberries. The objectives of the study were to determine how temperature and relative humidity affect cranberry storage life, and to assess the "chilling sensitivity" of cranberries.

To obtain vital information about storage conditions, cranberries were harvested from four commercial bogs and stored at temperatures ranging from 0 to 10 °C in combination with relative humidities ranging from 75% to 98%. According to Dr. Forney, "Fruit were stored under these conditions for up to six months and were evaluated monthly for marketability, decay, physiological breakdown, weight loss, and firmness immediately after removal and after an additional week at 20 °C. The percentage of marketable fruit declined substantially over time in all storage conditions, with 41% to 57% becoming unmarketable after 2 months as a result of both decay and physiological breakdown."

Forney concluded that relative humidity had a greater effect on fruit storage life than temperature. After five months, the amount of marketable fruit stored in high (98%) and medium (88%) relative humidity was 71% and 31% less than that stored in low (75% to 82%). He remarked, "Results suggest that cranberry fruit should be stored at 0 to 7 °C and 75% to 82% RH to retain marketable fruit."

The study outcomes can offer cranberry growers and processors important information about methods for prolonging freshness and marketability of fresh cranberries, and consumers will ultimately see the benefits of fresher, wholesome, antioxidant-rich berries.

Source: American Society for Horticultural Science