Aquatic Functional Products

Wardah Maulida Saldi, Erna Hastuti

Corrosion of carbon steel in chloride-rich environments remains a critical challenge, while conventional chitosan-based coatings often suffer from limited barrier integrity and durability. This study addresses this limitation by developing an eco-friendly chitosan–silica composite coating derived from crab shell waste and systematically evaluating the effect of silica loading (1–4%) on the corrosion protection of ASTM A36 steel under 10% NaCl immersion. Chemical interactions were examined using Fourier-transform infrared spectroscopy (FTIR), while corrosion performance was assessed through weight loss measurements, electrochemical impedance spectroscopy (EIS), and surface morphology observations. FTIR results confirmed the successful incorporation of silica and enhanced hydrogen bonding between silanol groups and chitosan chains. The composite coating containing 2% silica exhibited the highest corrosion resistance, achieving the lowest corrosion rate and the highest polarization resistance compared to pure chitosan and uncoated steel. The improved performance is attributed to enhanced barrier properties of the chitosan–silica composite, where the presence of well-dispersed silica particles limits chloride ion penetration. At higher silica loadings, corrosion protection declined, likely due to reduced coating uniformity. These findings demonstrate that controlled silica reinforcement introduces a distinct corrosion protection mechanism beyond conventional chitosan coatings and highlight the potential of bio-based hybrid coatings for sustainable steel protection.

Aquatic Functional Products

Astrid Indriana Hapsari

The small size of anchovy (Stolephorus spp) makes the fish easily torn and highly susceptible to quality deterioration, particularly when stored in fresh conditions. Moringa leaves (terrestrial product) and seaweed (marine product) were selected as immersion materials due to their natural bioactive compounds, such as antioxidants and antimicrobials, and to compare the most effective extract in maintaining fish freshness. The study aimed to analyze the effect of immersion duration and the effectiveness of the extracts. Immersion was conducted at room temperature for 4, 6, and 8 hours to determine the most effective duration in preserving fish quality. A concentration of 100% was applied to maximize the utilization of bioactive compounds. The experimental methodology compared anchovy samples treated with moringa leaf and seaweed extracts against untreated control samples, using a randomized block design (RBD) to minimize bias, with three replications to ensure reliability and statistical validity. Organoleptic evaluation indicated that the most effective immersion extracts were seaweed and moringa leaf extracts, with sensory scores of 8, characterized by clear eyes, red gills, transparent mucus, reddish flesh, fresh odor, and firm-elastic texture. The total microbial counts were 5.2 log CFU/g for seaweed extract and 5.32 log CFU/g for moringa leaf extract.

Aquatic Functional Products

Bagaspati L Sadewa, Tjipto Leksono, Santhy Wisuda Sidauruk

Naniura is a traditional fermented fish product from North Sumatra that is processed using organic acids derived from Jungga citrus (Citrus hystrix). This study aimed to evaluate the effect of Jungga citrus immersion time on sensory characteristics, physicochemical properties, lactic acid bacteria (LAB) population, and crude exopolysaccharide (EPS) content of tilapia naniura. Fresh tilapia fillets were immersed in Jungga citrus juice at a 1:1 (w/v) ratio for 0, 3, 4, and 5 h, followed by marination with spices. Sensory evaluation was conducted using hedonic and quality scoring tests with 15 moderately trained panelists. Physicochemical properties (water activity and pH), total LAB counts, LAB characteristics, and crude EPS content were analyzed using standard laboratory methods. The results showed that immersion time significantly affected sensory acceptance, physicochemical properties, LAB population, and EPS content (p < 0.05). The highest hedonic acceptance was obtained at 4 h of immersion, while the highest quality scores, LAB counts, and crude EPS content were observed at 5 h. Increasing immersion time decreased pH and increased water activity, indicating enhanced acid diffusion and protein modification. LAB isolates were identified as Gram-positive, non-motile, heterofermentative bacteria. These findings indicate that Jungga citrus immersion time plays a critical role in determining the sensory quality, microbial activity, and physicochemical stability of tilapia naniura. An immersion time of 4–5 h is recommended to achieve optimal product quality, LAB development, and potential EPS production, supporting the development of safe and functional traditional fermented fish products in Indonesia.

Aquatic Functional Products