New integrated process for production of edible and fishmeal powders from sardines: Drying kinetics and quality attributes

Abstract

The edible parts of fishes (fleshes with / without skeleton) as well as the by-products (heads and viscera) are processed into two types of powders intended for human consumption and aqua feeding respectively. Sardine fleshes were blanched in water (100 °C, 30 s), air-dried at different temperatures (50, 60 and 70 °C) and then ground to fine powders. Sardines by-products were cooked in water (90 °C, 20 min), air-dried at 75 °C and then ground to fine powder. The drying kinetics of fleshes and by-products were evaluated and fitted to five mathematical models. The effects of pretreatments and drying temperatures on the physicochemical, techno-functional properties (water and oil retention capacities), microbiological quality and quality degradation indicators (biogenic amines, TVB-N and TBARS) of the obtained powders were examined. Results showed that drying of fleshes and by-products occurred in the falling rate period. The examined models were found to fit adequately to the experimental data with the exception of two term model. Drying and blanching do not affect protein content. Even though these operations lead to decreased fat and mineral contents, the obtained powders are rich on protein and ω-3 fatty acids (EPA and DHA). Microbiological analysis showed that drying of blanched sardine flesh at 60 °C and cooked by-products at 75 °C provides safe end-products.