FISHERY BULLETIN: VOL. 71, NO. 1 



and were then steam desolventized. The other 

 half was desolventized as wet solids. 



Desolventizing consisted of placing approxi- 

 mately 454 g of either wet solids or dry solids 

 in an autoclave and steaming (exhaust vent 

 open) at 2 to 3 psi for 0, 5, or 10 min. Time of 

 exposure was determined from the time when 

 the autoclave reached pressure, which took about 

 2 min. After stripping, the sample was dried 

 overnight at ambient conditions and then milled 

 through a 40-mesh screen. 



Methods of Analysis 



Tests for soluble protein, emulsion stability, 

 residual IPA, and total volatiles were as reported 

 in the experiments on drying. Color of the sam- 

 ples was determined by reflectance analysis 

 (Dubrow, 1971), using a Beckman DB Spectro- 

 photometer with reflectance attachment. Re- 

 flectograms were obtained by scanning from 

 700 m/jL to 390 mfi.. Analysis of color was also 

 determined on a Hunter Color Meter, Model D25. 



32.3% in the nonsteamed solids to between 8.6 

 and 10.5% in the steamed solids. The loss in 

 solubility occurred during the come-up period 

 as evidenced by the low soluble protein content 

 of the solids from the min treatment. 



The loss in protein solubility was also accom- 

 panied by a loss in emulsion stability. All treat- 

 ments resulted in a separation of phases; emul- 

 sion, water, and solids. About 20 to 25% of the 

 water separated from the mixture. 



The effect of steaming to remove IPA showed 

 that after 5 min the residual alcohol was less 

 than 250 ppm, decreasing from 30,000 ppm at 

 min to 200 ppm after 5 min and to 75.5 ppm 

 after 10 min. The total volatiles of the FPC's 

 were 7.8%, 5.3%, and 4.9%, respectively. 



Steam desolventization of wet solids changed 

 the color of the FPC's. A significant darkening, 

 from a grayish tan to a grayish brown, occurred 

 in those samples steamed for 5 and 10 min. A 

 reflectance spectra of the 0-min and 10-min treat- 

 ments is shown in Figure 1. Hunter L, a, and 

 b values are presented in Table 3. 



RESULTS AND DISCUSSION 



Desolventizing Wet Solids 



Table 3 shows the effect of steam desolventiz- 

 ing wet solids on the salt soluble proteins, emul- 

 sion stability, color, residual IPA, and total vol- 

 atiles. 



The protein solubility of FPC's decreased from 



Desolventizing Dry Solids 



Table 3 also shows the effects of steam de- 

 solventizing dry solids on protein solubility, 

 emulsion stability, color, residual IPA, and total 

 volatiles. The initial protein solubility, prior to 

 treatment, was 28.2%. Although steaming the 

 FPC for min did not result in any great loss 

 in protein solubility, the 5-min and 10-min 

 steamed samples showed about a 57% loss in 



Table 3. — Effect of steam desolventizing FPC wet solids and FPC dry solids on the salt soluble protein, emulsi- 

 fying capacity, color, and volatile content. 



1 Separation into three phases: water, solids, emulsion. 



102 



