Development of an apparatus inactivating B. subtilis spore in Orange juice using High Electric Field AC Kunihiko Uemura, Isao Kobayashi and Takashi Inoue* National Food Research Institute, *Pokka co. 1. Introduction Heat treatment is commonly used to inactivate microorganisms in liquid foods in order to improve food safety and extend shelf life. However, heat treatment to kill spores also causes thermal damage to the food, which can adversely affect the flavor and lead to loss of nutrients. We developed an apparatus to apply a high electric field AC (HEF-AC) that inactivates heat-resistant microbe spores in liquid food while preserving the freshness of raw food. Contact E-mail address: [email protected] 1)K. Uemura and S. Isobe, J. Food Eng., 53, 203(2002). 2) K. Uemura and S. Isobe, J. Food Eng., 56, 325(2003). 3)T. Inoue, Y. Kawahara , S. Ikeda, S. Hijikata , S. Isobe and K. Uemura, JSFE., 8, 123(2007). Block diagram ○:Inactivate more than 3-log. △:Inactivate more than 2-log. ×:Inactivate less than 1-log. Tempera ture S.cerevi siae E.coli B.Subtilis B.cereus A.acidoca ldarius Geo.stearoth ermophilus 65℃ ○ △ 70℃ ○ ○ 110℃ × × 115℃ △ △ × 120℃ ○ ○ ○ × 130℃ ○ ○ × 135℃ △ 140℃ ○ 2. HEF-AC setup 1),2) 3. Inactivation of B.subtilis spore 3) HEF-AC system appearance Electrode Inactivation of selected microorganism 4. Improvement in quality of Orange juice Teflon block 1mm 32mm 6mm Titanium electorode Scale up Throughput: 2,000L/h •Inline test •Long run test -6 -5 -4 -3 -2 -1 0 100 110 120 130 Inacivating effect of B.subtilis Log(N/N 0 ) Temperature [°C] 0.3s 0.6s 0.9s Holding time F HEF-AC = 0.006 min 0 0.2 0.4 0.6 0.8 1 1.2 Raw HEF-AC UHT β-carotene [mg/L] 0 50 100 150 200 250 300 350 400 Raw HEF-AC UHT Hesperidin [mg/L] 38 39 40 41 42 43 44 45 Raw HEF-AC UHT Ascorbic acid [mg/L] 0.E+00 2.E+08 4.E+08 6.E+08 8.E+08 1.E+09 Raw HEF-AC UHT Limonene [AREA] 0.E+00 2.E+05 4.E+05 6.E+05 8.E+05 1.E+06 Raw HEF-AC UHT Linalool [AREA] -0.5 0 0.5 1 1.5 Fragrance Orange feel Aftertaste Color Refreshed feel Total Test way:7 steps (-3~+3) absolute scale ■ :HEF-AC ◆ :UHT Sensory evaluation Components analysis -2 -1.5 -1 -0.5 0 0 5 10 15 20 Inactivation effect of B.subtilis log(N/N0) Electric field [kV/cm] Temperature and holding time Electric field effect Temperature : 115°C NaCl consentration : 0.0025%~0.15% In Progress