CHANGES IN OIL CONTENT, FATTY ACID, AND VITAMIN E COMPOSITION IN DEVELOPING HAZELNUT KERNELS.
Kernel oil content increased while moisture content decreased during development. Oil concentration was between 59.6% and 67%, at harvest and the major lipid class was triglycerides. The fatty acids comprising the triglycerides showed some interesting seasonal patterns. Oleic acid increased from 10% to become the most abundant fatty acid at harvest (74%). Linolenic acid content was high (up to 40%) at the beginning of growth but then decreased to about 1% by the end of the season. Linoleic increased from about 4% to around 30% early in the season but then decreased although it finally represented a high proportion of total fatty acids (between 19–22%).
Total vitamin E increased as oil content increased. -tocopherol was the major form of vitamin E and its concentration increased to around 400μg/g oil throughout the season and was almost 95% of total vitamin E. -tocopherol was high at the beginning and decreased until there was none. -tocopherol was only a minor constituent and decreased from the beginning to around 10–20 μg/gm of oil at the end. -tocopherol increased during the first stage of growth and then decreased during the second and third stages. The amount of -tocopherol differed among the cultivars. The pattern of -tocopherol synthesis implies progressive methylation during development.