PREPARATION, PROPERTIES AND PRESERVATION OF LACTIC-ACID FERMENTED SHRIMP HEADS

Raw heads of the African river prawn (Macrobrachium vollenhovenii) wer e fermented with 5% (w/w) Lactobacillus plantarum as inoculum at 30 de grees C using 15% (w/w) cane molasses as a carbohydrate source. After incubation for 7 days, a desirable and stable pH, <4.5, was attained i n the anaerobic treatments which lasted until 30 days after the start of fermentation. Addition of trona at 5% (w/w) prior to fermentation r estricted protein hydrolysis by inhibiting the activity of endogenous autolytic enzymes. Addition of onion extract at 5 ml kg(-1) proved eff ective as an antioxidant as the thiobarbituric acid reactive substance s value remained low after 30 days' fermentation. In a storage experim ent, fermented shrimp heads were stored at 30 degrees C for 180 days a nd analyzed at intervals. The non-protein nitrogen increased and attai ned a maximum of 50.1% of total nitrogen content after 180 days. Proxi mate composition varied slightly during storage and there was a >12% l oss of tryptophan. (C) 1997 Published by Elsevier Science Ltd on behal f of the Canadian Institute of Food Science and Technology.