Ethanol Soaking Research Articles

Biochemical Studies on Some Chemical Characteristics of Sliced Egyptian Onions

ABSTRACTBiochemical studies were carried out on two widely distributed Egyptian onion varieties (Behairy and Selected Giza 6). Several treatments (soaking in tap water, boiling water, cold water, warm ethanol, or sodium chloride solution) were proposed to overcome onion reddening during industrial processing. Some chemical characteristics (L‐ascorbic acid, free amino acids, volatile sulfur compounds, carbonyl compounds, pungency and color) were determined in fresh, treated and stored sliced onions. Unsaturated fatty acids can be considered as a secondary source for carbonyl compounds and are involved in the formation of red pigments. Pronounced changes among hydrocarbons and little changes in sterols were due to application of various treatments and storage. In general, the most efficient treatments towards keeping onion quality were soaking the sliced onions in cold water or 5% (w/v) sodium chloride for 24 hr before onion dehydration.

Biochemical Studies on Some Chemical Characteristics of Sliced Egyptian Onions

AbstractBiochemical studies were carried out on two widely distributed Egyptian onion varieties (Behairy and selected Giza 6). Several treatments (soaking in tap water, boiling water, cold water, warm ethanol and sodium chloride solution) were proposed to overcome onion reddening during industrial processing. Some chemical characteristics (L‐ascorbic acid, free amino acids, volatile sulfur compounds, carbonyl compounds, pungency and colour) were determined in fresh, treated and stored sliced onions. The fatty acid composition of onion samples revealed that unsaturated fatty acids can be considered as a secondary source for carbonyl compounds and take place in the formation of red pigments. Pronounced changes among hydrocarbons and little changes in sterols were found due to application of various treatments and storage. In general, the most efficient treatments towards keeping onion quality were soaking the sliced onions in cold water and 5 % (w/v) sodium chloride for 24 hr before onion dehydration.