Shrinkage in canned mushrooms treated with xanthan gum as a pre-blanch soak treatment

Vacuum treating freshly harvested mushrooms with a 1 % xanthan gum solution (XVT)containing 0.25% sodium metabisulphite{SMBS) prior to blanching and canning gave a lower shrinkage value than for corresponding samples vacuum treated with water, or those canned by conventional means or the 3S process. A combination of chill storage (2-4°C) for 1-3 days coupled with 1 % XVT was found best and gave even lower total canning losses (chill storage loss+blanch loss+retort loss); these were6% lower than in the 3S process and 11.5% lower than for mushrooms canned by the conventional procedure. These data suggest that xanthan gum has considerable potential for reducing shrinkage in canned mushrooms. The XVT canned samples had an excellent colour and an acceptable texture. Further storage tests over a 9 month period with xanthan treated canned mushrooms showed than an SMBS level of 0. l % in the pre-blanch soak solution maintained an excellent colour in the canned product. No in-can mushroom shrinkage took place during the 9 month storage test.