LAUSR

Stability and microstructure of meat emulsion in Kai-yor (Thai chicken sausage) formulated with 4 different lipids and subjected to 2 levels of heat treatment were evaluated. Types of lipids included chicken fat (control), frozen rice bran oil (RBO), pre-emulsified RBO with soy protein isolate (SPI), and pre-emulsified RBO with a mixture of sodium caseinate and microbial transglutaminase (SC+MTG). The heat treatments were cooking and cooking followed by sterilization (cook-sterilization). Meat emulsions were prepared, steamed cooked, packaged in a retort pouch and sterilized. The results showed that frozen and pre-emulsified RBO with SC+MTG increased the stability of meat emulsion indicated by a reduction in fluid release. Hardness and chewiness of all reformulated Thai chicken sausages were higher than those of the control heated by cooking and cook-sterilization. The sterilization process negatively affected texture of all samples, nevertheless the meat emulsion formulated with pre-emulsified RBO with SC+MTG exhibited the lowest percentage decrease in hardness and chewiness. Scanning electron micrographs indicated that differences in the lipid phase affected the microstructure of meat emulsions. Sterilization altered and disrupted the protein matrix to different extents depending on the type of lipid. Replacing chicken fat with pre-emulsified RBO with SC+MTG resulted in greater formation of a protein matrix which was less severely damaged after sterilization than other lipids. It can be concluded that substitution of chicken fat by both frozen and pre-emulsified RBO (with SPI or SC+MTG) showed the potential for producing a cooked meat emulsion with better quality. CMU J. Nat. Sci. (2020) Vol. 19 (4) 792 However to achieve a satisfactory quality of sterilized meat emulsion, pre-emulsified RBO with SC+MTG offered superior alternative.