Standardising preprocess treatments for improved organoleptic quality and storage stability of carp pickle

Abstract- A study was under taken for developing a pickled product using meat of the carp, rohu (Labeo rohita). The meat of the fish has an intrinsic muddy flavor and presence of small bones because of which it is not popular in states like Kerala. The meat pieces were subjected to different preprocess treatments, viz., salting, drying, frying, baking, smoking and marinating in various combinations. Pickle was prepared using the pretreated meat following a base recipe and subjected to sensory evaluation. Muddy flavour was found to decrease with increase in smoking period. The most acceptable combination of treatments was found to be marinating fish meat pieces for 15 min followed by smoking for 3 h at 60oC and frying for 30 sec at 180oC in refined vegetable oil.

Vinegar- tamarind juice mixture in 1:1 proportion was found to be the most preferred acid source for preparing the pickle. Three types of pickles were then prepared using meat pieces subjected to the selected pretreatments and acid mixture, of pH values 4.0, 4.5 and 5.0, and storage studies were conducted for a period of 72 days. The organoleptic scores for odour, texture, taste and overall quality dropped significantly after 24 days of storage in the case of pickle of initial pH value 5.0, and became unacceptable on the 36th day.

Pickles adjusted to pH values 4.0 and 4.5, on the other hand, showed an increasing trend in sensory quality during the first few weeks of storage, possibly due to proper maturation, after which the sensory scores remained more or less steady for rest of the period. The total plate count showed no increase in pickles of pH 4.0 and 4.5 during storage, but it significantly increased in pickle of pH 5.0. This was accompanied by significant increases in total volatile base nitrogen content and pH in the latter. The product of initial pH value spoiled on the 36th day whereas the other two products remained acceptable and in good quality for the entire storage period. The peroxide value also increased at a greater rate in pickle of pH 5.0 indicating a higher rate of oxidation of oil absorbed during frying. Thus it was concluded that pH of 5.0 is unsuitable. Among the other two lots pH 4.5 was found more suitable as the product could be well preserved and the sourness was found to be less organoleptically compared to the pickle of pH 4.0 during storage period.