3.4. Free fatty acid content
FFA content at the beginning of the process represented 0.3% of the lipid content and increased to 3% at the end of fermentation (Fig. 2). Greater free fatty acid content was observed with increasing fermentation time, indicating lipolysis of Nham lipids during fermentation. Lipolytic activity at the beginning of fermentation was attributed to both lipases of the muscular tissue and microbial origin (Toldrá & Flores, 1998). Fermentation of Nham involved successive growth of different microorganisms dominated by lactic acid bacteria (LAB). However, Lactobacillus species are generally weakly lipolytic (Montel, Masson, & Talon, 1998). Selgas, Sanz, and Ordóñez (1988) showed the ability of the genus Micrococcus to hydrolyse triglycerides with long chain fatty acids, which are the most abundant in meat products. Since microbial lipases generally are very sensitive to pH, lipolysis at conditions relevant to Nham fermentation was likely mediated by lipases present in lysosomes of the muscle tissues. Molly, Demeyer, Civera, and Verplaetse (1996) confirmed the importance of endogenous lipase activity in Belgian sausages. These enzymes were still active even at the end of fermentation, and could be responsible for the decrease in phospholipids in this product.