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Item QUALITY ASSESSMENT OF FISH PEPTIDE POWDER PREPARED THROUGH ENZYMATIC HYDROLYSIS(Faculty of Fisheries Chattogram Veterinary and Animal Sciences University Chattogram - 4225, Bangladesh, 2025-06) Jannatul, MawaThis study investigates the quality assessment and economic feasibility of fish peptide powder produced from underutilized marine species Chrysochir aureus (Yellow fin croaker) and Sillago sihama (Sand whiting) through enzymatic hydrolysis using both commercial (pepsin) and natural (papain) enzymes. Enzymatic hydrolysis was carried out at different papain concentrations (5%, 10%, 15%) and a fixed ratio of pepsin (1:3000 w/w), and the resulting powders were evaluated based on sensory attributes, proximate composition, protein stability during storage, and production cost. Sensory evaluation showed that pepsin and 15% papain treatments produced powders with improved texture, odor, and overall acceptability. Proximate analysis revealed the highest protein content (84.26% and 83.23%) and lowest lipid and ash content in pepsin-treated powders for both species, indicating better nutritional quality. Protein retention was significantly higher in pepsin and 15% papain treatments during 45-day storage, under both ambient and refrigerated conditions. Economically, peptide powder production using natural enzymes demonstrated better profitability due to lower enzyme costs, with C. aureus yielding a higher cost-benefit ratio than S. sihama. The findings highlight the potential of enzymatic hydrolysis using affordable, natural enzymes and underutilized fish species for producing high-quality, cost-effective peptide powders suitable for food, nutraceutical, and pharmaceutical applications.Item Influence of Temperature and pH on Gel-Forming Ability and Protein Solubility of Frozen Reeve's croaker (Chrysochir aureus) Surimi(Faculty of Fisheries Chittagong Veterinary and Animal Sciences University Chittagong-4225, Bangladesh, 2025-06) Rawan, Shah Mohammed AbiThe present study investigated the influence of processing conditions, specifically temperature and pH on the gel-forming ability and protein solubility of frozen Reeve’s croaker (Chrysochir aureus) surimi. Experimental treatments included three temperatures (40°C, 50°C, and 60°C) and three pH levels (acidic pH 4, neutral pH 7, and alkaline pH 9). The findings revealed that temperature was the most critical factor affecting gel strength. Optimal gel strength, as determined by Bloom values, folding test grades, and Teeth cutting test scores were observed at 40°C and 50°C, where protein network formation was most favorable. In contrast, gel strength was significantly reduced at 60°C, with an approximate 70% decline, attributed to thermal denaturation and the breakdown of myofibrillar protein interactions essential for gel stability. pH conditions also significantly influenced gelation. Under neutral and alkaline pH levels (7-9), enhanced gel strength and protein solubility were recorded due to the stabilization of electrostatic and hydrophobic interactions. Conversely, acidic conditions (pH 4) led to weakened gels by protonating functional groups and inhibiting effective protein-protein interactions. The combined effect of high temperature (60°C) and low pH (4) resulted in the poorest gel quality due to intensified thermal denaturation and charge disruption, which impaired effective protein aggregation. At 60°C, protein solubility declined across all pH levels, with the most pronounced reduction observed at pH 4, indicating structural instability of proteins under acidic and high-temperature conditions. In contrast, protein solubility was maintained at 40°C-50°C under pH 7-9 but declined rapidly at 60°C due to heat-induced aggregation. Furthermore, frozen storage (up to 30 days) resulted in progressive protein degradation, leading to reduced gel strength and solubility over time. In conclusion, the study emphasized the importance of maintaining moderate temperatures (40°C-50°C) and neutral to alkaline pH levels (7-9) to ensure optimal gel strength and protein solubility in surimi. Avoidance of elevated temperatures and acidic conditions was essential to prevent irreversible protein degradation and gel weakening. These findings provide valuable insights for optimizing surimi processing and storage practices from Reeve’s croaker in the seafood industry.Item Effects of Packaging and Storage Condition on the Physicochemical and Microbial Properties of Whole and Powdered Gracilaria tenuistipitata(Faculty of Fisheries Chittagong Veterinary and Animal Sciences University Chittagong-4225, Bangladesh, 2025-06) Islam Shikha, ShanjidaGracilaria tenuistipitata is a widely utilized edible seaweed. This study evaluated the effects of packaging conditions (open, sealed and vacuum) and storage duration (up to 9 months) on the physicochemical and microbial quality of sun-dried whole seaweed and oven-dried powder (60 °C for 7–8 hours). Proximate composition, antioxidant capacity and phytochemicals (flavonoids and anthocyanins) were measured by AOAC, DPPH and colorimetric methods, while functional groups, sensory attributes and microbial quality were evaluated using FTIR, hedonic scale and selective media for total plate count and pathogens. Results showed that moisture reached 15.9% in whole and 8.62% in powdered seaweed. Protein declined to 19.31% in whole and 20.28% in powdered samples, while fiber, lipid and ash also decreased. Vacuum packed powder retained the highest quality with 4.17% moisture, 22.19% protein and 41.79% ash, whereas vacuum packed whole seaweed showed faster nutrient loss (11.08% moisture, 22.7% protein and 37.3% ash). Sealed packaging provided moderate protection. Antioxidant capacity decreased most (p < 0.05) in open packed whole seaweed (3.63 mg TE/100 g) and least in vacuum packed powder (4.31 mg TE/100 g). Vacuum packed powder preserved 82.5% of flavonoids and 139.76 mg TA/100 g anthocyanin. pH and water activity increased in open packs, indicating potential microbial growth. FTIR spectra detected degradation-related functional groups such as alkanes, aromatics and amino acids in open packed samples. Functional properties of powder, including water holding capacity (5.57 g/g, 5.36 g/g) and oil holding capacity (1.41 g/g, 1.25 g/g), remained higher under vacuum and sealed packaging, respectively. Sensory evaluation showed vacuum packed whole and powdered seaweed-maintained acceptability scores above 5, while open-packed samples dropped below 4 at 9 months. All samples were initially free from E. coli, Salmonella, Shigella and Vibrio cholerae. Total plate counts were lowest in vacuum packed powder (4 × 10² CFU/g) and reached unacceptable levels in open-packed whole seaweed (5.67 × 10⁵ CFU/g) at 9 months. In conclusion, vacuum packaging demonstrated the best preservation up to 9 months. Powdered seaweed showed higher stability than whole seaweed despite lower initial nutritional values, while sealed packaging was moderately effective for up to 6 months. These results will support the commercial potential of G. tenuistipitata as a stable, value added food product under optimized packaging conditions.Item Impact of Packaging and Storage Temperature on the Quality of Smoked Scomberomorous guttatus in Bangladesh(Faculty of Fisheries Chittagong Veterinary and Animal Sciences University Chittagong-4225, Bangladesh, 2025-06) Nahar Riya, SharminThe quality preservation of smoked Scomberomorus guttatus through effective packaging and storage temperature control is essential for enhancing food safety, shelf life, consumer acceptance, and value addition in Bangladesh. The aim of this research was to investigate the impact of different packaging materials (foil paper, polythene, and vacuum packs) and storage temperatures (room temperature and refrigeration at 4°C) on the physical properties, biochemical, microbial, and sensory aspects of smoked S. guttatus. Freshly caught fish were hot-smoked for 1 hour 30 minutes at 80 90°C temperature internally using rice husk as fuel and the smoked samples were then stored under the designated conditions. Immediately after smoking, sensory assessment was conducted using a 9-point hedonic scale showed high scores for appearance, color, odor, flavor, and texture, with an overall acceptability of 8.1 ± 0.40, indicating strong consumer appeal. The fish exhibited desirable biochemical characteristics, with moisture content of 61.95 ± 0.42%, protein 26.78 ± 0.35%, lipid 6.79 ± 0.22%, and ash 2.87 ± 0.18%. The TVB-N level was 13.21 ± 0.31 mg/100g, and the total plate count was 3.2 × 10² CFU/mL, all within acceptable limits. According to sensory, biochemical, and microbial analyses, the shelf life of smoked fish at room temperature was 3 days for foil packaging, 6 days for polythene, and 9 days for vacuum packaging. Under refrigerated conditions, the shelf life extended to 10 days for foil paper, 20 days for polythene, and 30 days for vacuum packaging. TVB-N and TPC values gradually increased during storage, reaching thresholds, with vacuum packaging showing the slowest rate of deterioration. Sensory scores declined below acceptability with storage time. These findings indicate that vacuum packaging combined with refrigeration is the most effective in slowing biochemical spoilage, microbial growth, and sensory degradation. This study provides valuable insights for optimizing post-harvest handling practices to ensure safer and higher-quality smoked fish products in Bangladesh.Item DEVELOPMENT OF HIGH-QUALITY SURIMI AND SURIMI BASED PRODUCTS FROM LOW-COST JEWFISH(Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram-4225, Bangladesh, 2025-06) Islam, SadiaJewfish (Otolithes ruber), is an underutilized marine species with firm, white flesh and excellent gel-forming ability, holds promise for surimi-based value-added products such as fish ball. This study evaluated the proximate composition, biochemical parameters (TVBN and NPN), microbiological quality (TPC and pathogenic bacteria identification), and sensory attributes of O. ruber fish ball prepared with different binding agents sticky rice, corn flour, wheat flour, and their combinations compared to a control (surimi only). Samples were vacuum-packaged and stored under chilled (4 °C, up to 15 days) and frozen conditions (−8 °C and −25 °C, up to 100 and 120 days, respectively). Throughout storage, gel strength declined over time, particularly under chilled conditions. The control (S) exhibited the lowest gel strength (2.20 to 0.46 N at 4 °C), while the sticky rice, corn flour formulation (S3) maintained the highest strength (11.63 to 10.90 N at 4 °C, 11.63 to 10.64 N at −8 °C and 11.63 to. and 9.50N at -25ºC). Moisture content significantly decreased (p < 0.05) during chilled storage, with the most notable reduction observed in S (79.15% to 78.03%) and the least in S3 (67.72% to 67.22%). Similar trends were observed under frozen conditions, with more gradual changes. As moisture declined, ash and carbohydrate contents increased, while protein and lipid contents decreased. Biochemical parameters such as total volatile base nitrogen (TVBN) and non-protein nitrogen (NPN) increased during storage. The control showed the highest TVBN at 4 °C (6.99 to 45.26 mg N/100 g), while S4 had the lowest (4.16 to 37.86 mg N/100 g). NPN values followed similar patterns. Microbial spoilage exceeded acceptable limits (>6 log CFU/g) by 12 days at 4 °C, whereas all samples remained microbiologically acceptable at frozen temperatures up to 120 days. Sensory evaluation revealed that fish ball with sticky rice (S1) had the highest overall acceptability across all temperatures, particularly when vacuum-packaged. Optimal shelf lives were 14–16 days at 4 °C, 80–100 days at −8 °C, and 80–120 days at −25 °C.Item Assessing the effects of elevated temperature on the expression of hsp70, hsp90, igf1, igf2, gh and ghrelin in Nile tilapia (Oreochromis niloticus)(Faculty of Fisheries, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram-4225, Bangladesh, 2024-06) Hossain, MD. NayeemGlobal climate change significantly influences environmental temperature, affecting fish growth, feeding patterns, and overall health. Understanding how fish respond to thermal changes is crucial, particularly for stress response, metabolism and growth in aquaculture. This study examines the effects of different acclimation temperatures on stress response and growth-related gene expression in Nile tilapia (Oreochromis niloticus). The research focused on the expression of heat shock proteins (hsp70 and hsp90), insulin-like growth factors (igf1 and igf2), growth hormone (gh) and ghrelin in juvenile Nile tilapia (O. niloticus) acclimated to 31°C (control), 34°C, and 37°C over 14 days. The results revealed that expression of hsp70 and hsp90 were significantly upregulated at 37°C in both male and female fish, indicating a pronounced stress response. In contrast, the expression of igf1, igf2 and gh was highest at 34°C, stimulating metabolic processes and promoting somatic growth. In comparison, significantly lower levels were observed at 37°C, suggesting an inhibitory effect of higher temperatures on growth-related processes. Expression of ghrelin followed a similar pattern to that of IGF and GH with higher levels at 34°C correlating with increased appetite and growth, but a decreased expression at 37°C, indicating reduced feeding activity due to thermal stress. These findings underscore the critical role of maintaining optimal temperatures in aquaculture settings and provide valuable insights into the physiological mechanisms underlying thermal adaptation in Nile tilapia, with implications for improving aquaculture practices and ensuring the health and productivity of farmed fish under varying environmental conditions.Item Gastrointestinal indices and length weight relationship of Mudskipper (Apocryptes bato) from two different habitats along the Bay of Bengal coast(Faculty of Fisheries, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram-4225, Bangladesh, 2024-12) Mahmud, Md. TuserThe length weight relationship (LWR) of fish is a crucial aspect of fisheries biology and management, providing information on the growth patterns, health, and ecology of fish populations. For the investigations, live Apocryptes bato, a mudskipper species was collected by hand net from two different coastal habitats Chattogram and Cox’s Bazar along the coast of Bay of Bengal. The objectives were to compare digestive efficiency, feeding patterns, and growth characteristics of A. bato across these two different habitats. The length weight relationship was calculated using a power function (W = aLb). The length weight relationship of A. bato was found to have an exponent "b" value of 2.78 and 1.72 (negative allometric growth) for both habitats for the pooled data, while the female in the Chattogram demonstrates positively allometric growth pattern here “b” value was 3.51. Measured gastrointestinal indices revealed that fish in the Chattogram region had higher visceral somatic index (VSI) and hepatosomatic index (HSI) values than fish in the Cox's Bazar region. However, relative length of gut (RLG) and intestine somatic index (ISI) values is comparably lower in the Chattogram region than the Cox’s Bazar. In Chattogram and Cox’s Bazar region, condition factor (K) ranged from 0.44 − 0.87 and 0.76 − 1.32 respectively and no statistically significant difference (p > 0.05) was observed between the K and relative condition factor (Kn) values of fishes from these two different habitats. Results of the present study also showed significant differences in the gastrointestinal indices between the two habitats indicating the necessity of habitat specific management for A. bato. Future conservation and management plans for coastal ecosystems can benefit from these findings, which expand our knowledge of how habitat specific factors affect mudskipper growth and feeding physiology.Item Comparative Analysis of Physiochemical Properties in Gelatin Extraction from Thai Pangas (Pangasianodon hypophthalmus) Skin and Bone by Alkaline, Acidic Methods and Commercial Gelatin(Faculty of Fisheries, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram-4225, Bangladesh, 2023-12) Das Alien, HemadriAquatic sources are gradually replacing mammalian sources like pigs and cows in the production of gelatin due to sociocultural and religious reasons. In Bangladesh, Thai Pangas (Pangasianodon hypophthalmus) is highly popular due to its affordability and easy availability. The research aimed to extract gelatin from skin and bone of this catfish and compare the efficiency of alkaline and acidic extraction techniques, focusing on gelatin yield and key physiochemical properties compared to commercial gelatin. Here three pretreatments were applied. Treatment 1 for 0.2% NaOH (T1) was an alkaline method of extraction. Treatment 2 for 0.2% H2SO4 (T2) was an acidic method of extraction. Treatment 3 was for 0.2% H2SO4, 0.2% NaOH and 1% Citric Acid (T3) was a combination of acid-base extraction method. It was observed that the skin gelatin sample (T1) of Thai pangas yielded a significantly higher amount of gelatin (16.61±0.52%) compared to bone gelatin. The research also found that three different brands of commercial gelatin had similar protein, ash, moisture, and lipid content. Furthermore, skin gelatin (T3) had proximate values that were comparable to the values of commercial gelatin. Skin gelatin T3 showed values that were equal to those of commercial gelatin, despite the fact that commercial gelatin had higher values than extracted gelatin for melting and setting temperatures, viscosity, pH, foaming capacity water holding capacity, fat binding capacity and foam stability. Between gelatin of skin and bone, skin gelatin (T3) had higher viscosity (2.36±0.01 mPa.s), water holding capability (1.29±0.02 ml/g), and fat binding capability (2.77±0.00 ml/g). On the other contrary, melting temperature, setting temperature, and pH higher in bone gelatin (T1). Gel strength of skin gelatin (T3) had value (268.51±1.46 g) that was quite near to commercial. It was observed that bone gelatin (T2) had the lowest value of foaming capacity (0.86±0.01%), and foam stability (0.59±0.00%). In this investigation, it was discovered that the Skin Gelatin (T3) exhibited better physical qualities than other pretreatments. It was shown in this study that Skin Gelatin (T3) had better physical properties compared to other treatments that were close to commercial gelatin.Item Assessment of the Socio- economic Condition of Different Stakeholders and Quality Aspects of Three Non Conventional Dry Fish Species available in the Market of Cox’s Bazar, Asadgonj and Rangamati, Bangladesh(Faculty of Fisheries, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram-4225, Bangladesh, 2023-12) Talukder, TwinkleFish drying is a traditional method of producing nutrient-dense food for humans. The goal of the current study was to examine the socio economic condition of different stakeholder and to assess the organoleptic quality, biochemical and microbiological composition of three non conventional dry fish available in the market of Cox’s Bazar, Asadgonj and Rangamati. This data was collected through questionnaires, Participatory Rural Appraisals (PRA), and cross-check interviews, and subsequently analyzed using Microsoft Excel and SPSS software. The greater percentages of participants were male in Cox’s Bazar (80%), Asadganj (90%), and Rangamati (70%) with 20%, 10%, and 30% females only. In Cox’s Bazar, Asadgonj and Rangamati respectively 30%, 40%, 30% of the participants reported having adequate storage facilities, 25%, 40%, 40% reported absence of storage facilities and 45%, 20%, 30% had no idea about proper storage and handling of dry fish. The study further identified the available dried species, including Bombay duct, Churi, Milk shark, Sting ray, Kukurjib, Surma. The sun dried non conventional dried fish were of highly acceptable and fit for human consumption in terms of organoleptic quality. The percentages of protein, ash, moisture, and lipid were calculated in accordance with AOAC protocol (AOAC, 2005). Protein content ranged from 37.96±4.40% to 57.77± 4.68%, the highest found in Kukurjib from Rangamati and lowest found in Stingray from Asadgonj. Lipid content ranged from 1.63±0.33% (Hangor from Cox’s Bazar) to 8.33± 2.92% (Kukurjib from Cox’s Bazar). Ash content ranged from 8.14± 1.51% to 14.66±3.79%, the highest found in Hangor from Asadgonj and lowest found in Kukurjib from Cox’s Bazar. Moisture content ranged from 20.33 ±0.88% to 30.05±1.75%, the highest found in Hangor from Asadgonj and lowest found in Kukurjib from Asadgonj. The TPC was highest in the dried Kukurjib collected from Cox’s Bazar (4.58×107 CFU/mL) and lowest in Rangamati (3.63×107 CFU/ mL). Among the tested bacterial strains of Salmonella p., Shigella sp., V. cholerae, V. vulnificus, V. parahaemolyticus, E. coli. the highest presence was found in the products of Cox’s Bazar area. The quality and safety attributes, along with their biochemical compositions suggest that these dried fish could be a viable and secure food option for human consumption.Item Efficiency of Lactic Acid Bacterium, Lactobacillus acidophilus, in Enhancing the Quality of Tilapia Fish Mince(Faculty of Fisheries, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram-4225, Bangladesh, 2023-12) Rehnuma Raisa, TabassomThis research focused on evaluating the impact of Lactobacillus acidophilus inoculation on the quality of the Tilapia fish mince. The quality of fish mince was compared with that of regular fish mince. The study assessed changes in organoleptic characteristics, biochemical properties (proximate compositions, TVB-N and NPN were determined using a modified version of the AOCA (2016) method) and changes in bacterial count. In the study, approximately 105 Lactobacillus acidophilus inoculated in 10 grams of tilapia fish mince and stored at 4°C. A normal fish mince was also kept at the same temperature. Parameters were measured weekly over a 6 week period. At first L. acidophilus growth was confirmed by using RT-PCR technique. Organoleptic test involved a panel (10 trained participants) evaluating color, smell, texture and general appearance. Lactic acid bacteria inoculated fish mince received higher consumer acceptance. The pH level notably decreased in the lactic acid bacteria inoculated fish mince (from 6.1±0.07 to 4.7±0.05) compare to the normal fish mince (from 6.6±0.04 to 5±0.08) throughout the study. TVBN content increased more rapidly in normal fish mince compare to lactic acid bacteria inoculated fish mince, with TVB-N content measuring 33.05±1.05 mg/100g and 30.36±1.35 mg/100g respectively in the last week. NPN content increased steadily in first four weeks for both samples, but in the last two weeks, the normal fish mince exhibited a rapid increase compare to the lactic acid bacteria inoculated fish mince. Proximate composition showed no significant difference (p<0.05) between the two samples. L. acidophilus bacteria displayed rapid growth in the inoculated sample during the initial three weeks, followed by a decreasing rate. Total bacterial load in normal fish mince increased throughout the study from 0.9×105 to 3.9×105 cfu/g, while lactic acid bacteria inoculated fish mince showed a decreasing rate 1.8×104 to 0.2×103 cfu/g. Notably, no pathogenic bacteria such as Salmonella spp., Shigella spp., or E.coli were detected in either sample. Overall, the lactic acid bacteria inoculated bacteria consistently exhibited better quality than the normal fish mince throughout the experiment. The study concluded that lactic acid bacteria have significant effect on the quality of tilapia fish mince, serving as biopreservatives.