Composition and content analysis of fluoride in inorganic salts of the integument of Antarctic krill (Euphausia superba)

Abstract

Ash of Antarctic krill integument (AAKI) was prepared by sintering the integument at 550 ° C under air atmosphere for 4 hours, and its composition was analyzed by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and electron dispersive spectroscopy (EDS). XRD results showed that the major phase in AAKI was ascribed to apatite. Besides, it was noticed that the (300) peak of AAKI shifted to 33.07°, which was coincident with that of fluorapatite (FA). The FTIR results confirmed the presence of phosphate ions, and the absence of -OH. The EDS results confirmed the presence of Ca, P, O and F elements in the ash sample. The content of FA in the ash was determined to be 50.4%, and the proportion of fluorine in the form of FA to the total fluorine in the integument was 40.5%. Based on the XRD, FTIR and EDS results, it can be concluded that FA was the main form of fluoride in the integument of Antarctic krill.

Advances in Technologies for Highly Active Omega-3 Fatty Acids from Krill Oil: Clinical Applications

“…Besides these essential elements, krill is characterized by a large quantity of fluoride (2400 mg/kg dry matter) which may cause skeletal fluorosis if its intake is high. However, the major quantity of fluoride is contained in the krill exoskeleton which could be removed during krill oil extraction to avoid excessive fluoride content reaching low fluoride levels (<0.5 ppm) [47].…”

Three‐liquid‐phase salting‐out extraction of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)‐rich oils from Euphausia superba

“…Antarctic krill comprises of abundant valuable nutrients like proteins, oils, and various smaller bioactive ingredients, such as vitamin A, astaxanthin, flavonoids, tocopherols, and minerals [2, 3]. The whole krill contains 11.9–15.4% proteins, which have higher quality than milk proteins [4, 5]. Interestingly, a novel flavonoid component in krill was characterized with a similar structure to 6, 8‐di‐C‐glucosyl luteolin [2, 6–8].…”

“…Moreover, EPA and DHA have been documented for nutritional and health‐related applications [16]. However, most of krill is consumed for the aquaculture feeds due to the maximum astaxanthin amount, but only approximately 12% of krill is utilized by mankind [4, 5]. The main limit factor is a high concentration of fluoride in Antarctic krill, such as 570 ppm fluorides found in muscles, 2594 ppm in the integument, and 6 ppm in the soft tissues [5, 17].…”

“…However, most of krill is consumed for the aquaculture feeds due to the maximum astaxanthin amount, but only approximately 12% of krill is utilized by mankind [4, 5]. The main limit factor is a high concentration of fluoride in Antarctic krill, such as 570 ppm fluorides found in muscles, 2594 ppm in the integument, and 6 ppm in the soft tissues [5, 17]. The high fluoride level in water can lead to mottling of the human teeth up to 30–50% [4].…”

“…The high fluoride level in water can lead to mottling of the human teeth up to 30–50% [4]. Besides, chronic fluorosis may cause osteosclerosis, bony exostoses, calcification of ligaments and tendons, and renal calculi [4, 5]. Therefore, the fluoride level in foods is limited strictly by the governments.…”