Effect Of Smoking And Thermal Processing on Nutritional And Organoleptic Qualities Of Retort Pouch Processed Carp

Abstract- A study was under taken in order to find out the effects of smoking and thermal processing on nutritional and organoleptic quality of carp meat. The major constraints which reduces consumer acceptability of carp are the presence of intramuscular bones, muddy flavour and the soft texture of meat. Grass carp (Ctenopharygodon idella). Was used for the study as a representative of carps. Skinned fillets were brined and drained under refrigerated condition were subjected to a particular period of smoking, viz., 1h, 2.5h and 5h at a temperature of 700C.

Quality of smoked products were analysed by estimating moisture content, pH, thiamine content and pepsin digestibility. All these parameters showed a decreasing trend upon increase in smoking period. Sensory evaluation studies were conducted on curried product prepared out from smoked fish fillets. Scores for all the parameters were found higher for smoked samples compared to the unsmoked sample. Muddy flavour was found decreasing with an increase in smoking period. Based on the results smoking for a period of 2.5h at a temperature of 700C was selected for thermal process studies.

For thermal processing studies fish pieces smoked for 2.5h was packed in retort pouches and process to various F0 values (2.01, 4.02, 6.05 and 8.1 min) at a temperature of 121.10C. The solid: liquid proportion of fish curry was 50:50 by weight at the time of packing and it was changed to 60:40 upon processing. pH of unprocessed product was 5.13 and it increased to 5.75 when it was processed for an F0 value of 2.01 min; thereafter a decreasing trend was observed with increase in F0 values. A decrease in thiamine content was observed with an increase in extent of thermal processing. Pepsin digestibility of retort pouch processed grass carp was also found decreasing significantly with increase in the F0 value. These indicates a greater loss of nutritional quality is occurring when the extent of thermal processing was increased. For assessing influence of type of container on nutritional quality of thermal processed product smoked grass carp pieces were packed in cans and retortable pouches and processed at 121.10C for achieving F0 values of 8.2 and 8.1 min respectively. Retort pouch processed product was observed with higher thiamine content and pepsin digestibility than canned product. Sensory evaluation parameters appearance and colour, taste and overall acceptability showed a decreasing trend where those for texture showed an increasing trend with increase in the extent of thermal process given. Intensity of smoke flavour was highest for unprocessed samples and it reduced with extent the extent of thermal process. However muddy flavour was not perceived in any of the products. The products processed at 121.10C for F0 value of 6.05 and 8.1 min were found commercially sterile. Therefore considering nutritional quality, sensory quality and extent of sterilization, thermal process for an F0 value of 6.05 min could be recommended for retort pouch processed smoked grass carp curry.