Effect of soup production from prussian carp (carassius gibelio) and addition of watercress (nasturtium officinale) on quality properties

This study aimed to determine the effects of watercress addition on some quality characteristics of soup produced from Prussian carp. The prepared soup samples (K, without watercress; S1, containing 1% watercress; S5, containing 5% watercress) were vacuum-packed and stored at 22±2°C for a period of 6 months. During the storage period, physicochemical, microbiological, and sensory analyses were conducted on the soup samples. Additionally, Scanning Electron Microscopy (SEM) analysis was performed to visualize the microscopic structure of the soup samples, and nutritional composition analyses, including fatty acid and amino acid contents, were carried out to determine their nutritional quality. During storage, the pH values ranged between 5.30±0.02 and 5.50±0.02, total volatile basic nitrogen (TVB-N) values ranged from 17.51±0.12 to 24.58±1.13 mg/100g, and thiobarbituric acid (TBA) values were found between 3.89±0.34 and 6.35±0.03 mg MDA/kg. Moisture content was between 4.89±0.11% and 8.28±0.14%, and water activity (aw) values ranged from 0.08±0.00 to 0.36±0.01. Microbiologically, the total mesophilic aerobic bacteria (TMAB) counts ranged from 4.28±0.01 to 5.90±0.01 log CFU/g, while lactic acid bacteria (LAB) counts ranged from 3.32±0.07 to 4.90±0.01 log CFU/g, and no yeast or mold growth was detected. In all sample groups, palmitic acid was the most abundant saturated fatty acid (SFA), oleic acid was the most abundant monounsaturated fatty acid (MUFA), and linoleic acid was the most abundant polyunsaturated fatty acid (PUFA). In terms of amino acid composition, glutamic acid was the most abundant among non-essential amino acids, and lysine was the most abundant among essential amino acids in all soup sample groups. SEM analysis revealed that all soup samples exhibited similar structural properties. According to the sensory evaluation, no significant changes were observed in parameters such as color, taste, odor, texture, and overall acceptability during the storage period, and S1 soup samples prepared with 1% watercress addition were the most preferred by the panelists.