The free fatty acid (FFA) content and FFA composition in the
dumpling filler were determined to explain the role of frozen storage
on lipid hydrolysis and oxidation. The total FFA concentration in the
dumpling samples generally increased with increasing frozen storage
time at −18 °C (P b 0.05) (Fig. 3). The samples contained 0.22% FFA
on day one, increasing to 0.31% and 0.37% at 90 and 180 d of storage,
respectively. Fatty acids are highly susceptible to oxidative processes
when in the free form. According to Sikorski and Kołakowska (1994),
there is circumstantial evidence that products of lipid hydrolysis promote
FFA production and protein denaturation. The increases in FFAs
suggest that lipolysis occurred during frozen storage. Another