Waste biogenic materials derived from seafood exploitation represent valuable resources of new compounds within the blue bioeconomy concept. Here, we describe the effectiveness of Raman technology implementation as an in-line tool for the demineralization process control of crustaceans or gastropods. Transparent chitin polymeric foils and calcium acetate by-products were obtained from three waste crustacean shells (C. sapidus, S. mantis, and M. squinado) using a slow, green chemical approach employing acetic acid. Progressive mineral dissolution and increasing of the Raman characteristic signal of chitin is shown in a time-dependent manner using NIR-Raman spectroscopy, while resonance Raman shows intact carotenoids in reacted shells after 2 weeks. Chitin foil products are species-specific, and the demineralization bath of the waste shell mixture can be effectively tracked by Raman tools for solvent control and decision making for the recovery of calcium acetate by-products. Comparatively obtained calcium acetate from Rapana venosa snail shells, the subject of Raman analyses, allowed assessing by-product identity, hydration status, purity, and suitability as recrystallized material for further use as a pharmaceutical compound derived from different crustaceans or gastropod species. Cross validation of the results was done using FT-IR, XRD, and SEM-EDX techniques. A hand-held flexible TacticID Raman system with 1064 nm excitation demonstrated its effectiveness as a rapid, in-line decision making tool during process control and revealed excellent reproducibility of the lab-based instrument signal, suitable for in situ evaluation of the demineralization status and solvent saturation control.

Waste biogenic materials from seafood exploitation are valuable resources of new compounds exploitation within the blue bioeconomy concept. Here, we describe the effectiveness of Raman technology implementation as an in-line tool for demineralization process control of crustaceans or gastropods. We produced transparent chitin polymer foils from three waste crustacean shells (C. sapidus, S. mantis and M. squinado) using a slow, green chemical approach employing acetic acid, and showed the progressive process of biogenic carbonate dissolution and increasing the Raman characteristic signal of chitin, in a time dependence manner. It turned that chitin foils obtaining is species-specific, and the demineralization bath of waste shell mixture can be effectively tracked by Raman spectroscopy, for solvent control and the recovery of the calcium acetate as valuable by-product. Comparatively, calcium acetate drug, a compound widely used in kidney failure diseases, or as additive in nutraceuticals and food industry, has been obtained here, following a green demineralization path of the sea snail Rapana venosa intact shell, assisted by Raman tech-nology, using 9% acetic acid (vinegar) solution for 14 days. To validate the final products identity and quality, The process of waste shells demineralization and the final products of the treatment were investigated using various Raman techniques and technologies, cross-validating the results with FT-IR, XRD and SEM-EDX techniques. NIR Raman spectroscopy revealed chitin bands in a time-dependent manner, while Resonance Raman spectroscopy showed the preservation of ca-rotenoids after two weeks of acetic acid treatment. A hand-held flexible TacticID Raman system with a 1064 nm excitation demonstrated its effectiveness as a rapid, in-line decision making tool during process control and revealed excellent reproducibility of the lab-based instrument signal, suitable for in situ evaluation of the demineralization status and solvent saturation control. The calcium acetate recovered from residual treatment solutions was assessed regarding its hydration status, purity, and suitability as recrystallized material for further use as pharmaceutical product or ingredient in complex formulations.

An unusual blue-purple shell coloration was observed in specimens of Rapana venosa collected as discarded biogenic carbonate along the Romanian Black Sea coast. This chromatic feature has not previously been reported for this species, which is typically characterized by a grey-brown exterior and bright orange-pink aperture. Despite the ecological and economic relevance of this veined rapa whelk, the chemical nature of its shell pigments remains poorly understood. Here, we present a comprehensive molecular and structural characterization of the pigments responsible for this atypical coloration.,Resonance and non-resonance Raman microspectroscopy with multiple excitation wavelengths were employed, complemented by surface-enhanced Raman scattering (SERS), Fourier-transform infrared spectroscopy (FT-IR), powdered X-ray diffraction (XRD), and SEM-EDX analysis. Raman analyses revealed the coexistence of aragonite and calcite with a clear cross-sectional gradient, aragonite being enriched in the inner shell layers and calcite towards the exterior. Pigment distribution was strongly excitation-wavelength dependent. Spectroscopic data excluded indigotin derivatives and caroteno-protein complexes as major chromophores responsible for the blue colouration. Instead, the coloration arises from a complex mixture of endogenous methylated polyenes with different conjugation lengths, including species with partial triple-bond character, embedded within the mineral-organic matrix. These polyenes coexist and interact with melanins and porphyrin-type compounds, producing the observed blue-purple hue. SERS analysis of ethanol extracts identified β-carotene at sub-micromolar levels as the only solvent-extractable carotenoid, confirming that the dominant polyenes are non-extractable and structurally bound within the shell framework.,This study reveals a previously unrecognized polyene-based pigment system in Rapana venosa shells and demonstrates how pigment-biomineral interactions and molecular conjugation length contribute to shell coloration, providing new insights into the naturally occurring polyenic chromophores in biomineralized tissues.