The combination of microbiological, biochemical, and quality index methods in quality evaluation of pacific white shrimps (Litopenaeus vannamei) preserved at 0°C

Nhat Tam Le^1*, Nguyen Que Anh Huynh¹, Nhu Khue Doan¹, Thuy Xuan Uyen Phan¹, Ba Thanh Nguyen¹, Sao Mai Dam¹, Thi Van Thi Tran², Le Phuong Lien Nguyen³, Van Hai Chu⁴, Huynh Anh Vu Truong⁴

¹Institute of biotechnology and food technology, Industrial University of Ho Chi Minh City, Vietnam

²Hue University, Hue University of Science, Vietnam

³Szent István University, Department of Refrigeration and Livestock Product Technology, Budapest, Hungary

⁴Center of Analytical Services and Experimentation Ho Chi Minh city, Vietnam

Abstract:

In this study, the sensory, microbiological, and biochemical qualities were used to examine the quality of Pacific white shrimps (Litopenaeus vannamei) preserved at 0°C during a 10-day period. The sensory quality was evaluated by a quality index (QI) that resulted from a quality index method (QIM) scheme. Meanwhile, the total viable count (TVC) and K-value were used to assess the microbiological and biochemical qualities of the shrimp. On day 9, the results from TVC and QIM have shown that the shrimp showed signs of spoilage, corresponding to a log CFU/g of 6.4 and a QI of 21.37, which is unacceptable to consumers. The QI increased linearly with storage days therefore the remaining shelf-life of the shrimp was estimated from a linear regression equation. In particular, this study found a linear relationship between QI, K-value, and hypoxanthine content. Furthermore, hypoxanthine itself could be considered as an independent quality index like the K-index. In conclusion, the quality of Pacific white shrimp was categorized into four different classes: excellent, good, acceptable, and moderately acceptable, based on its sensory and biochemical quality indicators.

Keywords: hypoxanthine, K-value, QIM, white pacific shrimp.

Classification number: 3.1