Extraction and characterization of chitosan from the fish scale (Labeo Rohita) application on preserving nutritional quality, shelf life and sensory quality of apple samples (Malus Domestica)

Abstract

Chitosan is a unique natural alkaline polysaccharide known for its excellent biological compatibility and biodegradability. This study emphasizes the value of post-harvest treatments for strawberries using chitosan as a method of preservation. Chitosan was extracted from fish scales (Labeo rohita) through a chemical process that involved both demineralization and deproteinization, resulting in a 1.5 % solution in its natural state. Various assessments, including physiochemical (weight loss, pH, total soluble solid, acidity, vitamin C, reducing sugar,) microbial (mesophilic bacteria, yeast and mold), sensory, and data analyses, were performed on chitosan-treated apple samples over 25 days, with comparisons made against uncoated apple samples. The total yield of chitosan from fish scale was 13.33 %. The moisture, ash and pH of the extracted chitosan was found to be 2.3 %, 2.0 % and 7.0. The chitosan was then coated to apple samples, and the sample’s physical and chemical composition was retained when compared to the uncoated samples. After the 25th day of storage, the weight loss of the coated and uncoated samples was 7.98 % and 11.86 %, from 0.87 %. Microbial growth was also noticeably lower in the treated apples compared to the control samples. After the 25th day of storage, the mesophilic bacteria in coated and uncoated samples were 3 CFU/g and 149 CFU/g. Similarly, after the 25th day of storage, the yeast and mold in coated and uncoated samples was 3 CFU/g and 170 CFU/g respectively. In terms of sensory attributes, the coated apples did not deliver any distinct flavors or aromas, and they were accepted for storage up to 25 days, while uncoated apples were not accepted before 10 days. Chitosan-coated apples received a strong level of acceptance. Therefore, chitosan extracts can serve as effective natural additives for extending the shelf-life of apple