HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ribeiro, C. V. D. M. Articles by Eastridge, M. L. Search for Related Content PubMed PubMed Citation Articles by Ribeiro, C. V. D. M. Articles by Eastridge, M. L.

Short Communication: Effect of Number of Extractions on Percentage of Long-Chain Fatty Acids from Fresh Alfalfa¹

Department of Animal Sciences, The Ohio State University, Columbus 43210

² Corresponding author: eastridge.1{at}osu.edu

Accurate determination of fatty acids in fresh forage is very important when studying biohydrogenation. Fatty acids from fresh alfalfa were extracted by hexane:isopropanol (H:IP, 3:2 vol/vol) in 3 sequential extractions. The percentage and profile of fatty acids from each of the 3 extractions were evaluated by a randomized complete block design with repeated measures in space. Samples of fresh alfalfa were randomly harvested and immediately submerged in liquid nitrogen. For the first extraction, approximately 5 g of the frozen alfalfa was mixed with 18 mL of H:IP per gram of material. Samples were then centrifuged and the supernatant was collected. The second and third extractions were done by adding H:IP to the pellet (3 mL/g of the original sample weight), mixing for 2 min, and then centrifuging. Samples were submerged in H:IP and stored in the dark at 8°C at all times. The solvent from each extraction was partially evaporated and the fatty acids methylated by methanolic HCl. Repeated extractions increased the percentage of total fatty acids recovered from the samples. The concentration of fatty acids in the alfalfa after 3 extractions was 4.0%. The first, second, and third extractions resulted in 92.7, 4.8, and 2.6% of the total fatty acids extracted, respectively. There was no effect of extraction on the proportion of 16:0, 18:0, 18:1, and 18:2 fatty acids. However, the proportion of 18:3 in the extract decreased from the first to the second extraction and the ratio of saturated to unsaturated fatty acid increased from the first to the second extraction. The results of this experiment revealed that the profile of fatty acids can vary with the number of extractions performed. The higher amount of 18:3 in the first extraction may reflect the higher proportion of linolenic acid in the more easily extracted plant fractions.

Key Words: fresh alfalfa • extraction • fatty acids

This article has been cited by other articles:

				J. T. Sylvester, S. K. R. Karnati, B. A. Dehority, M. Morrison, G. L. Smith, N. R. St-Pierre, and J. L. Firkins Rumen ciliated protozoa decrease generation time and adjust 18S ribosomal DNA copies to adapt to decreased transfer interval, starvation, and monensin J Dairy Sci, January 1, 2009; 92(1): 256 - 269. [Abstract] [Full Text] [PDF]