Potency of Catfish (Clarias sp.) Protein Hydrolysates as Candidates Matrices for Microbiology Reference Material

Abstract

Fish protein hydrolysate (FPH) is a derivative product of fish proteins containing smaller peptides and amino acids. FPH products have high water solubility, good emulsion capacity, and large expanding ability. W ith its functional properties, it allows FPH to be used as a raw material in the manufacturing of secondary microbiological reference materials. This study was intended to characterize catfish (Clarias sp.) FPH as a candidate for the matrix of microbial secondary reference. The FPH was prepared through enzymatic hydrolysis, freeze-drying and milling. The hydrolysis processes were carried out using 5% (w/w) papain, 55 °C for 5 hours, then the papain activity was stopped by increasing the temperature to 80 °C for 20 minutes.The FPH was combined with gelatine, sodium glutamate, glucose solution, and was spiked with Salmonella enteritica sv Enteritidis and freeze-dried. Results showed that catfish FPH was yellowish-white powder with a FPH yield of 11.05%. The proximate analysis of FPH revealed the moisture content of 3.77 ± 0.12%, ash content of 7.26 ± 0.03%, protein content of 86.09 ± 0.17%, and fat content of 1.38 ± 0.07%. The protein content of the FPH was greater than skim milk (33.42%). Carbohydrate levels of catfish FPH and skim milk were 1.56% and 57.46%, respectively. The best concentration of catfish FPH to perform as a microbiological reference material was 14%, obtained from highest viability of Salmonella bacteria and homogeny. The candidate for reference material were stable at storage temperatures of -20 o C.

Statistical Optimization of Salmonella Survival in Different Protein Hydrolysates

“…37 FPH is the most effective protein hydrolysate for sustaining the growth of Salmonella according to a study conducted by Petrova et al 38 There have been studies in which FPH was used in matrices along with the freeze-drying technique to create a secondary reference material for Salmonella. 14 The peptones obtained from cod FPH have demonstrated better growth of S. entereditis compared to the growth of Staphylococcus aureus when used in microbiological culture media. 38 Higher concentrations of FPH (20% and 25%) were unsuitable for the prolonged survival of S. enterica .…”

“…[8][9][10][11][12][13] Catfish protein hydrolysate has been used in the formulation of microbiological secondary reference materials by food-testing laboratories under ISO 17025:2017 to maintain data accuracy and prevent false-negative reporting. 14 Peptones are classified based on their source, and the four major categories are meat (e.g., tryptose and gelatin), vegetable (e.g., soy and pea), milkderived (e.g., casein and whey), and mycological (e.g., yeast and fungi). 10 Casein hydrolysate (CH), fish protein hydrolysate (FPH), and soy protein hydrolysate (SPH) were selected for this study to represent the three major categories of peptones.…”