Technical Abstract Search Details

Technical Abstract Details


Title 59H-12 Short-wave ultraviolet light irradiation effects on carrot juice
Presenter E. PALOU<sup>1</sup>, M. R. Arce-Garcia, L. Beristain, L. D. Bermudez-Aguirre, J. J. Gomez-Diaz, and A. Lopez-Malo. (1) Ingenieria Quimica y Alimentos, Universidad de las Americas-Puebla, Cholula, Puebla, 72820, Mexico
Abstract Vegetable processing and preservation technologies must keep fresh-like characteristics, while provide an acceptable and convenient shelf life, as well as assure safety and nutritional value. Nonthermal processes applied to food preservation without the collateral effects of heat treatments are being deeply studied and tested. One such procedure is the irradiation of foods with short-wave ultraviolet (UVC) light. The objective of this investigation was to determine the efficacy of UVC irradiation to treat carrot juice. The effects of several flow rates and UVC-doses on natural microflora and carrot juice color were examined. The UVC device consists of a 7.5 cm and 70 cm long glass tube fixed vertically with a 70 cm long UV-lamp (30 W, 254 nm, low pressure) inside the tube. Fresh carrot juice was pumped through the UVC chamber using a peristaltic pump adjusted to the desired flow rate (6 or 16 mL/s). Treated juice was re-circulated up to 25 times from a well agitated and disinfected double wall cylindrical vessel connected to a circulating water bath to control juice temperature at 15&#186;C. The effect of UVC-light on standard plate counts resulted in a 5-log cycle reduction after a 30 min treatment when juice was circulated at 6 mL/s, or after 12 min when using 16 mL/s. Both treatments reduced the bacteria to &lt;10 cfu/mL. However, mold and yeast counts were reduced only 1-1.5-log cycles, which represented survivors around 10<sup>2</sup> cfu/mL. UV-dosages varied depending on treatment and re-circulation times and flow rates, being for the longest irradiated samples 12.9 &#151; 34.4 J/cm<sup>2</sup>, sufficient to eliminate naturally present bacterial vegetative cells. An ANOVA demonstrated a non-significant effect (p&gt;0.05) of treatment time and UV-dosage on juice color when compared with fresh carrot juice. Continuous UVC-irradiation processes can be applied for heat sensitive juices, and combined with a refrigerated storage may prolong shelf life.
Year/Location2001 IFT Annual Meeting, June 23 - 27, New Orleans, LA
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