Variations in the fatty acid composition and nutritional value of Adriatic sardine (Sardina pilchardus Walb.) through the fishing season | Maščobnokislinski profil in prehranska vrednost jadranske sardele (Sardina pilchardus Walb.) v odvisnosti od sezone ulova

Inglés. We investigated the chemical composition, in terms of water, protein, ash, total fat and fatty-acid composition, of sardine meat, and estimated its nutritional value. The samples originated from Adriatic sardines (Sardina pilchardus Walb.) that were collected in the north Adriatic Sea through the winter, spring, summer and autumn seasons. The content of 20 fatty acids was determined by in-situ transesterification and capillary column gas-liquid chromatography, using nonadecanoic acid (19:0) as internal standard. The mean contents of the sardine meat were: 70.8% water, 21.0% protein, 2.5% ash and 6.4% fat. For the fatty-acid composition, 18.0% were mono-unsaturated, 42.6% polyunsaturated and 39.8% saturated. The total-fat content increased through the year, from winter to autumn (0.69 to 18.15 g/100 g meat). The fatty-acid composition in the sardine meat varied significantly, with the levels of the polyunsaturated fatty acids (4.6 g/100 g meat), and especially eicosapentaenoic acid (20:5n-3, 0.98 g/100 g meat) and docosahexaenoic acid (22:6n-3, 1.9 g/100 g meat), being the highest in autumn, before spawning. The n-6/n-3 ratio (0.13) and P/S ratio (7.6) show that sardine meat can and should be included in a balanced human diet. Considering the recommended daily intake of n-3 polyunsaturated fatty acids is 0.45 g per day for a healthy population, this would be consumed as 10 g sardine meat collected in the autumn or 100 g sardine meat collected in the winter.

Esloveno. Raziskovali smo kemijsko (vsebnost vode, beljakovin, maščob in mineralnih snovi) in še posebej maščobno kislinsko sestavo mesa sardel ter določili njeno prehransko vrednost. Jadranske sardele (Sardina pilchardus Walb.) so bile ujete v severnem Jadranskem morju v štirih različnih lovnih sezonah: pozimi, spomladi, poleti in jeseni. Z metodo in situ transesterifikacije in določitve na plinsko tekočinskem kromatografu smo določili 20 maščobnih kislin. Meso sardin povprečno vsebuje 70,8 % vode, 21,0 % beljakovin, 2,5 % mineralnih snovi in 6,4 % maščob; od skupnih maščobnih kislin je 18,0 % enkrat nenasičenih, 42,6 % večkrat nenasičenih ter 39,8 % nasičenih. Vsebnost maščob je močno nihala med sezonami (naraščala od zime proti jeseni, od 0,69 % do 18,15 %) in statistično značilno vplivala na maščobnokislinsko sestavo mesa. Največ večkrat nenasičenih maščobnih kislin (skupaj 4,6 g/100 g mesa), predvsem eikozapentaenojske (20:5n-3, 0,98 g/100 g mesa) in dokozaheksaenojske (22:6n-3, 1,9 g/100 g mesa) so vsebovale sardele jesenskega ulova (pred drstenjem). Razmerja n-6/n-3 (0,13) in P/S (7,6) kažeta, da imajo sardine visoko prehransko vrednost. Priporočen dnevni vnos večkrat nenasičenih maščobnih kislin (0,45 g/dan za zdravo populacijo) dosežemo že z dnevnim zaužitjem 100 g mesa sardel, ujetih pozimi, in 10 g mesa sardel, ujetih jeseni.