91C-6 |
Sporicidal effects of a continous-flow high pressure throttling process on honey |
V. AREEKUL and R. T. Toledo. Department of Food Science and Technology, University of Georgia, 2010 Food Science Building, Cedar Street, University of Georgia, Athens, GA 30602 Heat treatment in excess of 75 oC is not suitable for honey because of alteration of flavor, color, and granulation. Honey free of Clostridium botulinum spores can potentially be used in products fed to infants. High viscosity and temperature sensitivity precludes conventional HTST sterilization of honey. High pressure throttling (HPT) could potentially eliminate spores in honey. Inactivation of Bacillus megaterium spores and changes in the physiochemical characteristics of honey subjected to continuous flow HPT were studied The HPT system with pressure intensifier, throttling valve, holding tube, back-pressure valve and evaporative cooler was used. B. megaterium ATCC 14581 spores were inoculated (ca. 107 CFU/ g ) into buckwheat honey. Pressure was 255 MPa and flow was 1L/ min. The system was preheated with water followed by 55 oC honey. When temperature past the 15 s hold tube was stable, samples were removed. Spores were counted by pour plating. Antioxidant capacity (dye reduction), hydroxymethyl furfural (HMF, AOAC), and moisture content by refractive index were evaluated. At 255 MPa and 55 oC inlet, honey temperature was 110 oC at hold tube exit, compared to 90 oC when inlet was 35 oC. Spore inactivation was 44%, 50% and 75%, respectively and at 90 oC, 98 oC and 110 oC exit respectively, with a 15 s hold. The instantaneous heating and cooling and homogenizing effect of HPT inactivated spores at relatively low temperatures vs. heat alone. HPT honey at 110 oC exit showed no adverse quality changes. Antioxidant activity was 4.997 and 6.187 mM ascorbic acid equivalent/ g and HMF was 8.6 and 9 mg% for untreated and treated honey at 110 oC exit, respectively. A heater between the intensifier and throttling valve to boost temperature before throttling is needed to increase spore inactivation. HPT inactivated spores in honey with no adverse effect in physiochemical properties.
Session 91C, Food Engineering: Food process engineering
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