Development and quality evaluation of retort pouch processed Ramasseri idli

Abstract

Ramasseri is claim to fame for its simple breakfast dish called Ramasseri idli. These soft, moist, steamed cakes are made with fermented batter made from rice and urad dal. They taste salty with a hint of sourness. Various accompaniments served with it enhance its taste. Development and quality evaluation of retort pouch packaged Ramasseri idli was undertaken with specific objectives of standardisation of thermal process in retort pouch package, shelf life study and quality evaluation. Retort pouch packaging system is a flexible, laminated package that can withstand thermal processing temperatures and combines the advantages of both metal cans and plastic packages. Shelf life study and quality evaluation in terms of microbial analysis (total plate count), pH, water activity, texture and colour were done. Microbial analysis also showed that the product was safe up to three weeks of storage. The Ramasseri idli was procured and packaged in retort pouches with one idli and 5 g chutney powder packaged in LDPE in a single pouch. Four Different combinations of temperature and F 0 values (110°C-1D; 110°C-2D; 100°C-1D; 100°C-2D) was given to pouches and found out the time required for processing. After thermal processing the packets are stored for shelf life studies under ambient storage (A) and refrigerated storage (R) at 7°C. The processed product was analysed for microbial and physico-chemical qualities viz; moisture content, pH, water activity, colour and texture using standard procedure at regular intervals. From the storage studies the pH of the processed Ramasseri idli after four weeks of storage was found to show a reducing trend for most of the samples. It may be due to increase in acidity during storage. There was a slight increase in moisture content of the retort packaged Ramasseri idli during storage which was not significantly varying from initial readings. There were no significant changes in water activity when compared to control for processed ones. The effect of storage period on colour, signifies that L* value of stored thermally processed idli increases whereas a* values and b* values shows an increasing trend which does not vary significantly from in initial colour value of sample. The texture analysis indicated that the firmness of the processed samples tends to decrease just after thermal processing. During storage period there was an inconsiderable increase in firmness. Refrigerated sample showed more pronounced increase as compared to the ambient sample though there was only negligible increase in firmness. The increased firmness can be brought back by steaming the idli for one minute.The microbial load of samples just after processing was nil whereas the observed bacterial counts for most of the samples after three weeks shows best results i.e., not more than 50/ml prescribed by Prevention of Food Adulteration Rules, 1956 (PFA, 2000). During sensory evaluation various parameters such as colour, texture, taste and overall acceptance were evaluated by a 5 point sensory scale. Based on the sensory evaluation, the thermal processed Ramasseri idli by four treatments showed best results up to three week of storage of which samples processed at 100°C F 1 and stored at refrigerated condition was found to be the best. Cost economics of the thermally processed Ramasseri idli in retort pouch was calculated and the cost of retort pouch contains one idli and LDPE packaged chutney powder was found to be Rs. 12/- Based on above results it could be concluded that the retort pouch processing is an ideal method of preserving Ramasseri idli for long period of storage. It was found from the experiment that the product could be stored for three weeks without contamination and deterioration in product quality. The best thermal processing method for retort pouched product was found to be 100°C- 1D refrigerated storage (T3-R), since the values obtained from physico-chemical and microbiological analysis of the above sample were not significantly varying from the control sample.