Đánh giá chất lượng cảm quan và một số chủng vi khuẩn gây thối cá ngừ chù nguyên liệu bảo quản bằng oligochitin kết hợp với nước đá

Abstract

    This study was conducted to evaluate the sensory and bacterial content in frigate tuna raw material caught in Khanh Hoa sea, Vietnam and then preserved by oligochitin (1÷3kDa) of 1,0% combined with ice (2±1ºC). Bacterial content evaluation included TPC, Shewanella putrefaciens and Pseudomonas spp of frigate tuna raw material (1000±50 gr/fish). The result showed that sensory quality satisfactory was for 21 days, starting to deteriorate on day 22; TPC was over the standard limit from day 16; Pseudomonas spp exceeded the threshold causing rot, about 2.1x10⁹ cfu/g from day 22; Shewanella putrefaciens exceeded the threshold causing rot, about 1,5x10⁹ cfu/g from day 18. Compared to the samples that was only used ice for preservation: Sensory quality lasted 1.9 times longer; TPC was 1.67; Pseudomonas spp was 1.65; and Shewanella putrefaciens was 1.59 times lower respectively.

Keywords: oligochitin, frigate tuna, sensory evaluation, bacterial content of frigate tuna.