EFFECT OF SOME SPICES AND THEIR VOLATILE OILS ON THE QUALITY ATTRIBUTES OF FROZEN AND SEMI-FRIED FISH FILLETS

Abstract

This study was carried out to evaluate chemical composition, chemical, physical, microbiological and sensory properties of uncooked and semi-fried coated tilapia fillets which manufactured by using two spices mixtures and their volatile oils i.e., garlic and cumin (GC) and garlic and parsley (GP) during frozen storage at -18oC for 3 months, Also, chemical components, antioxidant and antimicrobial activities of garlic, cumin and parsley volatile oils and their mixtures were evaluated. Results indicated that volatile oils and their mixtures can be sorted according to their antioxidant and antimicrobial activities potency in the following descending order: GC > GP > garlic > cumin > parsley. Proximate composition of coated tilapia fillets were not affected by the type (GC or GP) and form of additives (volatile oils or spices powder) but significantly affected by cooking process and frozen storage period at -18oC. Moisture content of coated tilapia fillets was significantly decreased by semi-frying process. However, crude protein, crude fat, total ash and carbohydrates contents were significantly increased by semi-frying process. Coated tilapia fillets prepared without additives had significantly higher TVN, TMA, TBA, pH, water holding capacity values and cooking loss than tilapia fillets coated with different types of additives. Also, spices volatile oils mixtures were more effective than spices powder mixtures on reduction of TVN, TMA and TBA values. Semi-fried coated tilapia fillets had significantly lower TVN, TMA, water holding capacity, plasticity and cooking loss but significantly higher TBA and pH values than uncooked coated tilapia fillets. The T.V.N, TMA, TBA, pH and cooking loss values of coated tilapia fillets were significantly increased by frozen storage period increment. The uncooked tilapia fillets coated without additives had higher total bacterial count, coliform, staphylococcus aureus, lipolytic and proteolytic bacteria counts than uncooked tilapia fillets coated with different additives. Also, the total bacterial counts decreased by the semi-frying process. However, other types of bacteria were inhibited by semi frying process. Also, coating tilapia fillets with spices powder mixtures and their volatile oils mixtures led to improve sensory properties compared with control. Moreover, volatile oils mixtures more effective in improving sensory properties and decreasing microbial load of tilapia fillets.