present investigation is to determine if a chem- 

 ical pretreatment affects the quality of pre- 

 served blue crab meat. 



MATERIALS AND METHODS 



Types of blue crab meat, methods of preser- 

 vation by freezing, heating, or freeze-drying, 

 methods of packaging, storage conditions, and 

 methods of taste-panel evaluation are the same 

 as described in Strasser et al. (1971). The 

 9-point rating scale used for the panel eval- 

 uations is given in Figure 1-4. 



The following two procedures were used with 

 the various preservative solutions listed below. 



Dipping Method 



Preweighed crab meat was placed into a 

 strainer, dipped into the preserving solution 

 for 30 sec, and then allowed to drain for 90 

 sec before further processing (freezing, pas- 

 teurization, sterilization, or freeze-drying). 



Spray (Glazing) Procedure 



Just after freezing a sample of crab meat 

 by immersion in food-grade Freon 12^ it was 

 spread out on a stainless steel screen. The 

 spraying solution was sprayed on the sample 

 from a Sprayon Jet Pack which was kept ap- 

 proximately 9 inches away from the sample. 

 Spraying was done in a swaying action for 

 about 15 sec (Fig. II-l). After another stain- 

 less steel screen was placed on top, the sample 

 was turned over to spray the other side. Then 

 the sample was refrozen by Freon immersion. 



Chemical Preservative Solution Used 



over evenly with the powder before being 

 frozen. 



Monosodium glutamate. — An aqueous solu- 

 tion containing 2% monosodium glutamate was 

 used for the dipping treatment and for glazing 

 samples by the spray procedure. 



Instead of dipping or spraying treatments, 

 four crab meat samples received a dusting with 

 monosodium glutamate powder. The meat was 

 spread out on stainless steel screens and dusted 



Ascorbic acid. — Although most of the crab 

 meat samples treated with ascorbic acid were 

 dipped in a 3% aqueous solution, a 1% solution 

 was used for some of the samples. The 3% 

 solution was also used to glaze several samples 

 by the spray procedure. Two other samples 

 were glazed using a 1 % spray solution but this 

 solution also contained 1% carboxymethylcel- 

 lulose (a thickening agent) to give a better 

 coating effect. 



Condensed phosphates, salt, and citrate. — ■ 



Two different phosphate compounds were used. 

 One solution contained lO^r sodium tripoly- 

 phosphate plus 2% sodium chloride. It was 

 used for the dipping treatment and for glazing 

 samples by the spray procedure. The other 

 solution contained 2% sodium acid pyrophos- 

 phate alone, and it was used only for the dipping 

 treatment. A third solution containing 5% 

 sodium chloride and l^r sodium citrate was 

 also used only for the dipping treatment. 



Sodium nitrate. — An aqueous solution con- 

 taining 1% sodium nitrite was used for the 

 dipping treatment. 



Tenox-6. — The spray procedure was used 

 with a 3% solution of Tenox-6 in ethanol. 



' Trade names are used to facilitate description ; no 

 endorsement of product is implied. The chemical name 

 for Freon 12 is dichlorodifluoromethane. 



Figure ll-l. — .Spraying of crab meat with protective 

 chemical solutions. 



17 



