PENENTUAN LAJU KERUSAKAN MINYAK DAN BAWANG PUTIH KERING DALAM OPERASI PENGGORENGAN HAMPA (TINJAUAN ASPEK TEKNIS) Determination of Oil and Garlic Chips Deterioration Rate during Vacuum Frying (Study on Engineering Aspect)

Garlic was fried continually with vacuum frying equipment using temperature 85C and ratio of garlic to oil of 1/10 (w/v) for 15 hours. Frying time was 75 minutes for each with final yield of garlic chips was 0.35, final moisture content of 4.2%, and final oil content of 32.6%. Physical and chemical characteristics for oil and garlic chip deterioration based on alysin content showed that the alysin content of garlic chips was 1.99-2.65 times fresh garlic with decrease constant was 0.04 hour-1. Free fatty acids formation was 0.0184% hour -1 with free fatty acids range 0.029-0.058%. It was below standard value of free fatty acid i.e. 0.5%. Peroxide value formation was -0.11mek kg -1 hour-1 with peroxide value ranged 9.5514-10.6642 meq kg-1. It was also below standard value of 50 meq kg -1 . Carotene deterioration was 0.0184% hour -1 with its content ranged 0.029-0.058%, that still below standard value 0.5%. Fatty acids formation was 0.0184 % hour -1 with carotene range between 6.05-11.44% per 100 gram. Frying oil lightness value ranged 46.6-48.5, redness value ranged 16.7-18.8, and yellowness value ranged 20.0-24.6. Lightness decreased with decreasing rate constant of 0.036 hour-1, redness 0.013 hour -1 , and yellowness 0.17 hour -1 . Garlic chip lightness value ranged 56.0-58.1, redness value ranged 20.9-27.5. and yellowness value ranged 29.9-32.1. Lightness of garlic chip decreased with rate constant of 0.017x2 + 0.218x, redness of 0.023x2 0.331x, yellowness of -0.083x 2 + 1.2x. Correlation between peroxide deterioration of oil to garlic chips was 0.65, correlation between free fatty acid deterioration of oil to garlic chip was -0.78, correlation between lightness of oil to garlic chip was -0.75, correlation between redness of oil to garlic chip was -0.89, and correlation between yellowness of oil to garlic chip was -0.68. This result showed that oil life cycle was 150 hours.