Use of autoclaving in the preparation of homogenates for determining the proximate chemical and fatty acid composition of fish

Development in lipid analysis: Some new extraction techniques and in situ transesterification

“…Hence in situ synthesis must be carried out in samples with low moisture contents, or after removing water to below critical limits. This pretreatment adds the advantage of facilitating the penetration of solvents and is often used prior to the lipid extraction (7), although in some samples the extraction yield may be reduced as a consequence of the alteration of the physical structure of the matrix (78). In performing in situ FAME synthesis, different procedures have been used to remove water.…”

“…These peaks can be avoided by removing both the acetone produced in the reaction and the unreacted 2,2′-dimethoxypropane before adding the catalyst, so that the mixture with the catalyst is prevented and the artifacts are absent (81,82). Oven-drying procedures can bring about alterations in unsaturated fatty acids (75,78), so when pretreatment is necessary, freezing-drying the samples is mainly chosen for removing water.…”

The use of direct transesterification methods and autoclaving for determining fatty acid yields from dried Philippine thraustochytrids, a potential source of docosahexaenoic acid

“…Increased fatty acid yields were observed when autoclaving was applied to cyanobacteria during analysis (Sheng et al, 2012). Autoclaving of minced barramundi fish prevented losses in DHA associated with freeze drying and it was hypothesized that autoclaving denatured lipolytic enzymes that may mediate in vivo/ex vivo oxidation (Williams et al, 1995). Presently, autoclaving had no effect on fatty acid yields with conventional extraction followed by transesterification, but decreased yields were observed in polyunsaturated fatty acid recoveries with direct transesterification.…”

“…Studies on the effects of autoclaving during fatty acid analyses are limited and the reports that do exist appear to use autoclaving to assists in the lipid extraction process by promoting cell disruption (Lee et al, 2010;Prabakaran & Ravindran, 2011;Sheng et al, 2012;Williams et al, 1995). In microalgae, autoclaving freeze dried biomass slightly increased lipid yields relative to extraction without disruption, but the autoclaving lipid yields were significantly lower than those observed with microwave disruption with no information on very long chain polyunsaturated fatty acids being provided (Lee et al, 2010;Prabakaran & Ravindran, 2011).…”

“…The effect of sterilization of the powder by autoclaving on the fatty acid composition was also examined in order to facilitate experimental use as a rodent feed component. The use of autoclaving during fatty acid analyses have been reported for microalgae (Lee, Yoo, Jun, Ahn, & Oh, 2010;Prabakaran & Ravindran, 2011), cyanobacteria (Sheng, Vannela, & Rittmann, 2012) and fish homogenates (Williams, Barlow, Brock, & Rodgers, 1995) with the focus of promoting cell disruption to increase lipid recoveries. The impact of autoclaving on the content of DHA of microalgae is not known.…”