Comparative Study of Different Walnut (Juglans regia L.) Varieties Based on Their Nutritional Values

Polyphenols, fatty acids, and mineral composition were studied in eight Persian walnut (Juglans regia L.) samples: 'Milotai 10' (M10) and 'Alsószentiváni 117' (A117) Hungarian varieties derived from two Hungarian growing areas (Pálháza-P and Berzék-B), 'Chernivets'ky 1' from Ukraine, and 'Chandler' from the United States of America, Chile, and Brazil purchased on the Hungarian consumer market. The aim was to reveal which walnut variety is the most suitable for consumption from a nutritive point of view. In comparison, both Hungarian varieties grown in Hungarian climatic conditions had on average approximately 33% more polyphenols, approximately 22% more SFAs (saturated fatty acids), and approximately 27% more MUFAs (monounsaturated fatty acids). Regarding the minerals, calcium, magnesium, phosphorus, and sodium were present in higher concentrations in both Hungarian varieties. Among the Hungarian-bred varieties, M10 mainly reached a higher compounds content, but the effects of the fruit site conditions were not clearly detected. Other varieties contained mainly potassium, copper, and zinc, such as 'Chandler' harvested from Chile. 'Chernivets'ky 1', harvested from Ukraine, had outstanding cinnamic acid and linoleic acid contents compared to the other examined varieties. All 'Chandler' samples (mainly the American) contained 11% more PUFAs compared to the samples derived from Hungary.