Optimization of fish gelatin drying processes and characterization of its properties

Abstract

Fish skin is a raw material used for gelatin production. It can satisfy consumers with specific socio-cultural and religious needs. Different technologies have been studied for drying gelatin. Therefore, it is relevant to understand the influence of drying conditions on the final product. This study aims to optimize drying methods such as convection hot air alone and combined with infrared radiation to obtain gelatin from acoupa weakfish skin by using composite central rotational designs 22 and 23 and response surface methodology. The gelatin obtained from the optimized conditions were characterized based on their physical, chemical, technological, and functional properties. The desirability function results show the convection hot air as the most effective method when conducted at 59.14 °C for 12.35 h. Infrared radiation at 70 °C for 2.0 h and convective drying at 70 °C for 3.5 h were the best condition of the combined process. The gelatins obtained had gel strength of 298.00 and 507.33 g and emulsion activity index of 82.46 and 62.77 m2/g in the combined and convective methods, respectively, and protein content above 90%. These results indicate that the processes studied can be used to produce gelatin with suitable technological and functional properties for several applications.

Optimization of the Extraction of Chitosan and Fish Gelatin from Fishery Waste and Their Antimicrobial Potential as Active Biopolymers

“…Process 1 in Figure 2 clearly shows fish gelatin with poor organoleptic properties. In this process, it is necessary to include extractive stages that deodorize and improve the sensory qualities of the final gelatin [ 16 ]. Process 2 in Figure 2 shows that the use of activated carbon in the filtering stage substantially improves the sensory aspect.…”

“…A higher yield is obtained when the extraction process is carried out with acid solutions, since the acid converts the triple helix of collagen into single chains, while the alkaline solutions transform it into double chains [ 12 ]. In addition, the method used to remove moisture is fundamental to obtaining gels with good mechanical properties, which is also key in industrial scale-up due to the high economic costs it generates [ 16 ].…”

Extraction of Gelatin From Poultry Byproduct: Influence of Drying Method on Structural, Thermal, Functional, and Rheological Characteristics of the Dried Gelatin Powder

“…The 3,410-3,448 cm −1 represents amide-A, 1,635 cm −1 represents amide-I, 1,527-1,334 cm −1 represents amide-II, and 1,242-871 cm −1 represents amide III bands. The amide-A band is owing to stretching NH vibrations, indicating gelatincoiled structure, since stretching of free NH group vibrations is generally observed at 3,400-3,440 cm −1 (22). These vibrations are beneficial for the analysis of protein secondary structure in the IR spectral region (18).…”

“…These vibrations are beneficial for the analysis of protein secondary structure in the IR spectral region (18). The amide II peaks in the gelatin samples are attributed to an out-of-phase CN stretch with inplane NH deformation combination styles of the peptide groups, whereas amide III of gelatin samples is indicative of disorders in the molecules of gelatin and are possibly allied with the triplehelix structure loss (22). Kanwate et al (16) reported Amide-A at 3,294-3,273 cm −1 , Amide-B at 2,919, 2,928, and 2,919 cm −1 , Amide-I at 1,632.93, 1,634.36, and 1,631.50 cm −1 , Amide-II at 1,537, 1,529, and 1,524 cm −1 and Amide-III bands at 1,236, 1,239, and 1,236 cm −1 for freeze-dried, spray dried, and vacuum dried samples fish gelatin samples, respectively.…”