ABSTRACT

The random discharge of marine fish waste into the coast generates environmental pollution. However, a better valorization of these by-products leads to the extraction of sustainable biomolecules. Chitosan is a natural biopolymer that can be produced from various marine by-products, in particular the crustacean shells, crabs, and fish scales. The aim of this current study is the extraction of chitin and characterization of chitosan obtained after a deacetylation reaction from sardine scales (S. pilchardus) as a new marine source. The β form of chitin extracted undergoes deacetylation in 40% NaOH at 121°C for 20 min. The chemical structure of obtained chitosan was characterized based on Fourier transforms infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Scanning electron microscope (SEM), and Energy-dispersive X-ray spectroscopy (EDS). The physicochemical properties of obtained chitosan such as the ash, moisture, nitrogen, solubility, molecular weight, fat, and water-binding capacity were also determined. According to the results of FTIR and XRD analysis, the degree of deacetylation (DDA), and the crystalline index (CrI) value of obtained chitosan is respectively about 87% and 95%. The SEM and EDS analysis revealed respectively fibrillar and pleated morphology with the presence of three major elements characterizing the chitosan, which are C, O, and N. The physicochemical analysis showed that the rate of ash, moisture, and nitrogen in obtained chitosan were respectively about 0.10, 0.34, and 7%. The solubility, molecular weight, fat, and water-binding capacity of produced chitosan were found to be 93%, 5.86 kDa, 310, and 510% respectively. Sardina pilchardus scales could be considered a promising and alternative source of chitin and chitosan, which will be applicable in a large number of fields.

Implications: Direct rejection of marine biowaste as fish scales in nature, port, or fish processing plants, is a dramatic problem that is growing day after day. These uncontrollable discharges cause marine pollution and promote bacterial growth, which leads to a degradation of the soil and air quality. Taking into account the objectives of sustainable development, better development of these by-products would make it possible to produce valuable biomaterials that will be applied in various fields and which have benefits for the environment and humans. The central objective of this research is accentuated on the enhancement of Sardina pilchardus scales; by the conversion of chitin into chitosan and the determination of its physicochemical characterization. The obtained chitosan from Sardina pilchardus scales could be applied in the agricultural and food industry.

摘要

海洋鱼类废物随机排放到海岸会产生环境污染。然而，这些副产物的更好的增值导致可持续生物分子的提取。壳聚糖是一种天然的生物聚合物，可以从各种海洋副产物，尤其是甲壳类贝壳，蟹和鱼鳞中产生。这项当前研究的目的是从沙丁鱼鳞片（S. pilchardus）脱乙酰化反应后获得的几丁质的提取和壳聚糖的表征。作为新的海洋资源 提取的几丁质的β形式在121°C下于40％NaOH中脱乙酰20分钟。基于傅立叶变换红外光谱（FTIR），X射线粉末衍射（XRD），扫描电子显微镜（SEM）和能量色散X射线光谱（EDS）对获得的壳聚糖的化学结构进行了表征。还确定了获得的壳聚糖的理化性质，例如灰分，水分，氮，溶解度，分子量，脂肪和水结合能力。根据FTIR和XRD分析的结果，获得的壳聚糖的脱乙酰化度（DDA）和结晶指数（CrI）值分别为约87％和95％。SEM和EDS分析分别显示了纤维状和褶状形态，并存在表征壳聚糖的三个主要元素，理化分析表明，所得壳聚糖中的灰分，水分和氮的比率分别为约0.10、0.34和7％。发现生产的壳聚糖的溶解度，分子量，脂肪和水结合能力分别为93％，5.86 kDa，310和510％。沙丁鱼鳞片可被认为是甲壳素和壳聚糖的一种有前途的替代来源，可应用于许多领域。

含义：由于自然界，港口或鱼类加工厂中的鱼鳞，直接拒绝海洋生物废物是一个日益严重的问题。这些不可控制的排放会造成海洋污染并促进细菌生长，从而导致土壤和空气质量下降。考虑到可持续发展的目标，更好地开发这些副产品将使其有可能生产出有价值的生物材料，这些材料将应用于各个领域，并有益于环境和人类。这项研究的中心目标是加强沙丁鱼鳞片的规模。通过将几丁质转化为壳聚糖并确定其理化性质。从中获得的壳聚糖Sardina pilchardus秤可用于农业和食品工业。