2)Municipal Food and Environmental Laboratory of Raahe area, P. O. Box 25, FIN-92101 Raahe, Finland

The berries of sea buckthorn (Hippophae rhamnoides L.) are one of the richest sources of vitamin C among edible fruits. Ascorbic acid is considered the most unstable of the vitamins in fruits and vegetables. It is easily destroyed during harvesting, processing, storage, and cooking.

The present study determined the losses in vitamin C (L-ascorbic acid) content of sea buckthorn products caused by processing. Berries of sea buckthorn cultivars Tytti and Terhi were collected at North Ostrobothnia Research Station on 10^th – 14^th of September 1999 and stored at -20°C until processed and analyzed. The vitamin C contents of berries, juice, extract residue of juice (bulb and seeds), jelly and jam were determined by HPLC.

The vitamin C content of partially thawed berries was 195 mg/100 g. In completely thawed berries the vitamin C content was 17% lower than in partially thawed berries. The vitamin C content of juice was 214 mg/100 g. After juice processing on average 41% of the vitamin C in berries was lost with the pulp. In jam the berries contained on average 105% of the vitamin C compared to the thawed berries before processing. In jellies the vitamin C contents were on average 84% of the juice used as raw material in processing.

In conclusion the vitamin C in sea buckthorn berries seems to have good stability in processing, especially in jam where whole berries are used.