Rapid freezing of herbal products by gaseous nitrogen.

DOI: 10.21047/1606-4313-2017-16-4-66-74
UDC 621.56/.59; 641.52; 664.8.036.2

Rapid freezing of herbal products by gaseous nitrogen.

Venger K. P., Popkov V.I., Feskov O. A., Shishkina N. S., Karastoyanova O.V., Shatalova N.I.

For citation: Venger K.P., Popkov V.I., Feskov O.A., Shishkina N.S., Karastoyanova O.V., Shatalova N.I. Rapid freezing of herbal products by gaseous nitrogen. Vestnik Mezhdunarodnoi akademii kholoda. 2017. No 4. p. 66-74

The article presents the experimental stand on the basis of the two-bandtunnel in the rapid freezing apparatus of LindeGasRusCompany with cryogeniccylinder for liquid nitrogen. The standhas the control and measuring systems includinginstruments to measure temperature, heat flux,and velocity of the gaseous nitrogen,and software fordata processing. The graphs for the temperature distribution on the surface, in the center of the product,and for the environment along the length of the apparatus, and also for the heat flux during cooling and freezing by gaseous nitrogen was obtained experimentally. Experimental data of the main cooling parameters (durationtand the heat transfer coefficienta)for the blanched carrot layer of the width d= 0.01 m at the temperatures of gaseous nitrogen ts = –40 and –60 0C, proving the adequacy (at 4-6 %) of calculated data obtained bythe developed mathematical model (seethe previousarticle)are presented, which proves the validity of the modeluse in a wide range of performance parameters. The technology and results of the blanched carrot quality analysisafter pre-cooling (1st zone), freezing(2nd zone) in the nitrogen tunnel apparatus,and subsequent storageare shown. The high efficiency of usinglow temperature gaseous nitrogen for precooling and the subsequent freezingof blanched vegetable raw materials is proved: microbiological safety enhances,appearanceand shelf lifeof plant productsextend.

Keywords: experimental stand, measuring and control system, tunneling machine, gaseous nitrogen, herbal products, blanching, quality indicators.

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