Influence of ohmic heating on rheological and electrical properties of reconstituted whey solutions
Küçük Resim Yok
Tarih
2009
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Inst Chemical Engineers
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Reconstituted whey solutions (in the range of 8-24% w/v solute concentrations) were heated from 20 degrees C to prescribed temperatures (30, 40,50, 60, 70 or 80 degrees C) ohmically by applying voltage gradients of 20, 30 or 40 V/cm, and conventionally at water bath. Electrical conductivity changes with increasing temperature were linear during ohmic heating. Whey solutions have non-Newtonian characteristics since Herschel-Bulkley model satisfactorily fitted the experimental shear stress-shear rate data. "n" values were in the range of 0.520-1.503. The whey solution having 24% concentration had a yield stress of 0.006-0.024 Pa at low temperatures. Although temperature and concentration were critical factors for the consistency and the electrical conductivity changes during heating (p < 0.01), the voltage gradient was not effective statistically. The high correlation (between -0.910 and -0.991) was obtained between changes of electrical conductivity and consistency coefficient values during ohmic heating. Since activation energies for ohmic heating (26.34-45.79 kJ/mol) depending on solute concentration were lower than conventional heating (26.70-50.04 kJ/mol), reconstituted whey solutions were less sensible to temperature changes during ohmic heating. It was recommended that ohmic heating could be applied as a faster alternative heating method in the whey processing. (C) 2009 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Açıklama
Anahtar Kelimeler
Ohmic, Rheology, Electrical conductivity, Whey
Kaynak
Food and Bioproducts Processing
WoS Q Değeri
Q2
Scopus Q Değeri
N/A
Cilt
87
Sayı
C4
