Changes in Physically-Chemical Parameters of Latvian Cranberries During Storage

The main purpose of the present research was to investigate the changes in physical-chemical parameters of fresh Latvian cranberries during storage. Cranberry (′Steven′, ′Bergman′, ′Pilgrim′, ′Early Black′, and ′Ben Lear′) fruit were collected at a processing plant in Kurzeme region, Latvia, in the first part of October 2010. For the experiments, also wild cranberries were collected in the bogs of the same region and at the same time. The berries were rinsed with tap water for 3±1 min, then strained for 10±1 min (mainly for visual cleanness), and afterwards stored in closed non-perforated polypropylene (PP) boxes in air ambiance and in glass jars in a cold boiled-water ambiance at 3±1 °C. Quality parameters of the berries were tested each three months using standard methods: vitamin C content - by high-performance liquid chromatography (HPLC); organic acids - by HPLC; moisture - by oven-dry method; colour parameters - by device COLOR TEC PMC; pH - by potentiometric method; anthocyanin - by spectrophotometrical method; and phenolic compounds - by HPLC. The shelf life of cranberries packaged in closed PP boxes in air ambiance was six months, but of cranberries packaged in glass jars in water ambiance - 12 months. The research showed that differences in moisture content, pH value, colour intensity, and anthocyanin content among the cranberry cultivars under different ambient conditions during storage were not significant. During 12 months of cranberry storage in glass jars in water ambiance, the content of vitamin C decreased on average by 90%, organic acids - by 54%, and phenolic compounds - by 60%. During six-month storage in closed PP boxes in air ambiance, the content of vitamin C decreased on average by 99%, organic acids - by 30%, and phenolic compounds - by 34%.