Influence of lipid oxidation on the digestive efficiency of Antarctic krill oil: insights from a simulated gastrointestinal digestion model.

Lipid oxidation profoundly impacts its digestibility, a topic that has been predominantly investigated in triglyceride (TAG)-based dietary lipids. However, there is a dearth of similar research on lipids with diverse classes, such as Antarctic krill oil (AKO), which encompasses a spectrum of lipids including glycerides and phospholipids. This study aimed to elucidate the influence of lipid oxidation on the digestibility of AKO through a simulated gastrointestinal digestion (SGID) model. Post-SGID, AKO exhibited oxidative changes, evidenced by an escalation in peroxide value, conjugated diene value, thiobarbituric acid reactive substances and Schiff base formation. Concurrently, the digestibility of oxidized AKO was found to be inferior to that of fresh AKO, as indicated by a diminished hydrolysis degree of TAGs and phosphatidylcholine (PC), along with a reduced release of free fatty acids. Furthermore, co-digestion with tea polyphenol palmitate was observed to mitigate the oxidation of AKO and the digestion of PC during the SGID, while exerting no significant impact on TAG digestion. Notably, the emulsification capacity of oxidized AKO in a simulated intestinal fluid (without pancreatin and phospholipase A2) was also found to be inferior to that of its fresh counterpart. These findings suggest that lipid oxidation may adversely affect the emulsification capacity of AKO under simulated intestinal conditions, thereby leading to a decrement in digestibility.

Mechanism of discoloration of Antarctic krill oil upon storage: A study based on model systems.

The reddish-orange color of Antarctic krill oil fades during storage, and the mechanism remains unclear. Model systems containing different combinations of astaxanthin (ASTA), phosphatidylethanolamine (PE), and tocopherol were subjected to accelerated storage. Among all groups containing ASTA, only the ones with added PE showed significant fading. Meanwhile, the specific UV-visible absorption (A470 and A495) showed a similar trend. Peroxide value and thiobarbituric acid reactive substances increased during storage, while ASTA and PE contents decreased. Correlation analysis suggested that oxidized PE promoted fading by accelerating the transformation of ASTA. PE content exceeded the critical micelle concentration (1µg/g) indicating the formation of reverse micelles. Molecular docking analysis indicated that PE also interacted with ASTA in an anchor-like manner. Therefore, it is speculated that amphiphilic ASTA is more readily distributed at the oil-water interface of reverse micelles and captured by oxidized PE, which facilitates oxidation transfer, leading to ASTA oxidation and color fading.

Krill Oil Ameliorates Liver Injury in Diabetic Mice by Activating Antioxidant Capacity and Inhibiting Ferroptosis.

Diabetic liver injury (DLI) has raised attention in recent years. Liver injury results from type 2 diabetes mellitus (T2DM), and in turn accelerates T2DM development by exacerbating insulin resistance. However, effective approaches for mitigating DLI are surprisingly rare. Krill oil (KO) is an alternative source of omega-3 polyunsaturated fatty acids, possessing antioxidant and anti-inflammatory capacities. Here we investigated the effect of KO supplementation on DLI in a mouse model of T2DM induced by streptozotocin and high-fat diet. The diabetic mice developed glucose intolerance, elevated serum alanine aminotransferase and aspartate aminotransferase, and hepatic pathological injuries such as vacuolation, lipid accumulation and fibrosis deposition, the effects of which were mitigated by KO. Further investigation showed that KO ameliorated the DM-induced expression of fibrotic and inflammatory genes. Notably, KO dramatically reduced hepatic oxidative gene expression, lipid peroxidation and ROS production, all of which are hallmarks of ferroptosis. The inhibitory effect of KO on ferroptosis was confirmed by the KO-decreased hepatic expression of GPX4, COX2 and ACSL4, as well as the KO-reduced hepatic iron deposition. Further, KO restored hepatic NRF2 antioxidant signaling which combats ferroptosis. The present study may provide KO supplementation as a viable approach for the intervention of DLI.

A comprehensive study of the colloidal properties, biocompatibility, and synergistic antioxidant actions of Antarctic krill phospholipids.

Excipient selection is crucial to address the oxidation and solubility challenges of bioactive substances, impacting their safety and efficacy. AKPL, a novel ω-3 polyunsaturated fatty acids (PUFAs) esterified phospholipid derived from Antarctic krill, demonstrates unique antioxidant capabilities and synergistic effects. It exhibits pronounced surface activity and electronegativity at physiological pH, as evidenced by a critical micelle concentration (CMC) of 0.15 g/L and ζ-potential of -49.9 mV. In aqueous environments, AKPL self-assembles into liposomal structures, offering high biocompatibility and promoting cell proliferation. Its polyunsaturated bond-rich structure provides additional oxidation sites, imparting antioxidant properties superior to other phospholipids like DSPC and DOPC. Additionally, AKPL augments the efficacy of lipophilic antioxidants, such as alpha-tocopherol and curcumin, in aqueous media through both intermolecular and intramolecular interactions. In sum, AKPL emerges as an innovative unsaturated phospholipid, offering new strategies for encapsulating and delivering oxygen-sensitive agents.

Krill Oil and Its Bioactive Components as a Potential Therapy for Inflammatory Bowel Disease: Insights from In Vivo and In Vitro Studies.

Krill oil is extracted from krill, a small crustacean in the Antarctic Ocean. It has received growing attention because of krill oil's unique properties and diverse health benefits. Recent experimental and clinical studies suggest that it has potential therapeutic benefits in preventing the development of a range of chronic conditions, including inflammatory bowel disease (IBD). Krill oil is enriched with long-chain n-3 polyunsaturated fatty acids, especially eicosapentaenoic and docosahexaenoic acids, and the potent antioxidant astaxanthin, contributing to its therapeutic properties. The possible underlying mechanisms of krill oil's health benefits include anti-inflammatory and antioxidant actions, maintaining intestinal barrier functions, and modulating gut microbiota. This review aims to provide an overview of the beneficial effects of krill oil and its bioactive components on intestinal inflammation and to discuss the findings on the molecular mechanisms associated with the role of krill oil in IBD prevention and treatment.

Extraction, identification, and molecular mechanisms of α-glucosidase inhibitory peptides from defatted Antarctic krill (Euphausia superba) powder hydrolysates.

The objective of this study was to explore the potential of Antarctic krill-derived peptides as α-glucosidase inhibitors for the treatment of type 2 diabetes. The enzymolysis conditions of α-glucosidase inhibitory peptides were optimized by response surface methodology (RSM), a statistical method that efficiently determines optimal conditions with a limited number of experiments. Gel chromatography and LC-MS/MS techniques were utilized to determine the molecular weight (Mw) distribution and sequences of the hydrolysates. The identification and analysis of the mechanism behind α-glucosidase inhibitory peptides were conducted through conventional and computer-assisted techniques. The binding affinities between peptides and α-glucosidase were further validated using BLI (biolayer interferometry) assay. The results revealed that hydrolysates generated by neutrase exhibited the highest α-glucosidase inhibition rate. Optimal conditions for hydrolysis were determined to be an enzyme concentration of 6 × 103 U/g, hydrolysis time of 5.4 h, and hydrolysis temperature of 45 °C. Four peptides (LPFQR, PSFD, PSFDF, VPFPR) with strong binding affinities to the active site of α-glucosidase, primarily through hydrogen bonding and hydrophobic interactions. This study highlights the prospective utility of Antarctic krill-derived peptides in curtailing α-glucosidase activity, offering a theoretical foundation for the development of novel α-glucosidase inhibitors and related functional foods to enhance diabetes management.

Euphausia pacifica emulsified oil powder improves sleep quality in partially sleep-restricted healthy volunteers.

Although it is known that adequate sleep is crucial for maintaining a healthy lifestyle, approximately 30% of the general population has experienced insomnia. Thus, a better understanding of the relationship between food components and sleep quality is needed. North Pacific krill, Euphausia pacifica, is rich in marine n-3 polyunsaturated fatty acids in phospholipid form as well as 8R-hydroxy-eicosapentanoic acid. Here, emulsified oil powder derived from this krill was used in a trial involving 64 participants to assess its potential to enhance sleep quality. Consumption of the powdered emulsified oil was found to reduce drowsiness upon waking and enhance fatigue recovery, and for participants aged 40 and above, an improvement in sleep cycle was observed. In conclusion, consumption of krill emulsified oil powder was effective in enhancing sleep quality for individuals with partial sleep restrictions.

Characterization of oxylipins in Antarctic krill oil (Euphausia superba) during storage based on RPLC-MS/MS analysis.

Antarctic krill oil (AKO) is rich in polyunsaturated fatty acids (PUFAs), but is prone to oxidative degradation, resulting in the formation of oxylipins, which compromise AKO quality. Herein, we used reversed-phase-high performance liquid chromatography-tandem mass spectrometry (RPLC-MS/MS) to perform qualitative and semi-quantitative analyses of oxylipins in AKO during storage. A total of 27 oxylipins were identified. A notable decrease in epoxy oxylipins (from 41.8 % to 26.9 % of the total oxylipins) was observed, whereas the content of dihydro oxylipins initially increased and then decreased with 48 h, as a pivotal point for AKO quality decline during storage. We suspected that the ratio of dihydroxyl and epoxy oxylipins could be a novel oxidative index to evaluate the oxidation of AKO. Statistical analysis allowed the identification of five oxylipins which showed unique correlations with various indexes. The findings discussed herein provide important new insights into mechanisms of oxidation occurring in AKO during storage.

Mechanism of color change in Antarctic krill oil during storage.

Antarctic krill oil (AKO) is reddish-orange in color but undergoes changes during storage. To investigate the color deterioration and potential mechanisms involved, the changes in color, endogenous components (astaxanthin, fatty acids, and phospholipids), and reaction products (aldehydes, α-dicarbonyl compounds, and pyrroles) of AKO upon storage were determined. Although the visual color of AKO tended to darken upon storage, the colorimetric analysis and ultraviolet-visible spectrum analysis both indicated a fading in red and yellow due to the oxidative degradation of astaxanthin. During storage of AKO, lipid oxidation led to the formation of carbonyl compounds such as aldehydes and α-dicarbonyls. In addition, phosphatidylethanolamines (PEs) exhibited a faster loss rate than phosphatidylcholines. Moreover, hydrophobic pyrroles, the Maillard-like reaction products associated with primary amine groups in PEs accumulated. Therefore, it is suggested that the Maillard-like reaction between PEs and carbonyl compounds formed by lipid oxidation contributed to color darkening of AKO during storage.

Foam-templated oleogels constructed by whey protein isolate and xanthan gum: Multiple-effect delivery vehicle for Antarctic krill oil.

To address the limitations of Antarctic krill oil (AKO) such as easy oxidation, unacceptable fishy flavor and low bioaccessibility of astaxanthin in it, a multiple-effect delivery vehicle for AKO is needed. In this study, whey protein isolate (WPI) and xanthan gum (XG) were utilized to construct AKO into oleogels by generating foam-templates. The effects of the concentration of XG on the properties of foam, cryogel and the corresponding oleogels were investigated, and the formation mechanism of oleogel was discussed from the perspective of the correlation between foam-cryogel-oleogel. The results demonstrated that with the increase of the concentration of XG, the foam stability was improved, the cryogel after freeze drying had a more uniform network structure and superior oil absorption ability, and the corresponding oleogel had excellent oil holding ability after oil absorption. The AKO oleogels showed superior oxidative stability compared with AKO. The in vitro digestion experiments demonstrated that the bioaccessibility of the astaxanthin in this oleogel was also considerably higher than that in AKO. In addition, this oleogel had masking effect on the odor-presenting substances in AKO, while retaining other flavors of AKO. The foam-templated oleogel can be considered as a multiple-effect vehicle for AKO to facilitate its application in food products. This study provides theoretical basis and data support for the development and utilization of novel vehicle for AKO, broadening the application of AKO in the field of food science.

Novel Ca-Chelating Peptides from Protein Hydrolysate of Antarctic Krill (Euphausia superba): Preparation, Characterization, and Calcium Absorption Efficiency in Caco-2 Cell Monolayer Model.

Antarctic krill (Euphausia superba) is the world's largest resource of animal proteins and is thought to be a high-quality resource for future marine healthy foods and functional products. Therefore, Antarctic krill was degreased and separately hydrolyzed using flavourzyme, pepsin, papain, and alcalase. Protein hydrolysate (AKH) of Antarctic krill prepared by trypsin showed the highest Ca-chelating rate under the optimized chelating conditions: a pH of 8.0, reaction time of 50 min, temperature of 50 °C, and material/calcium ratio of 1:15. Subsequently, fourteen Ca-chelating peptides were isolated from APK by ultrafiltration and a series of chromatographic methods and identified as AK, EAR, AEA, VERG, VAS, GPK, SP, GPKG, APRGH, GVPG, LEPGP, LEKGA, FPPGR, and GEPG with molecular weights of 217.27, 374.40, 289.29, 459.50, 275.30, 300.36, 202.21, 357.41, 536.59, 328.37, 511.58, 516.60, 572.66, and 358.35 Da, respectively. Among fourteen Ca-chelating peptides, VERG presented the highest Ca-chelating ability. Ultraviolet spectrum (UV), Fourier Transform Infrared (FTIR), and scanning electron microscope (SEM) analysis indicated that the VERG-Ca chelate had a dense granular structure because the N-H, C=O and -COOH groups of VERG combined with Ca2+. Moreover, the VERG-Ca chelate is stable in gastrointestinal digestion and can significantly improve Ca transport in Caco-2 cell monolayer experiments, but phytate could significantly reduce the absorption of Ca derived from the VERG-Ca chelate. Therefore, Ca-chelating peptides from protein hydrolysate of Antarctic krill possess the potential to serve as a Ca supplement in developing healthy foods.

Development and characterization of self-emulsifying high internal phase emulsions using endogenous phospholipids from Antarctic krill oil.

High internal phase emulsions (HIPEs) have emerged as a promising structured oil system in food industry. This study developed self-emulsifying HIPEs (SHIPEs) using Antarctic krill oil (KO) with endogenous phospholipids as surfactant and algae oil as a diluent. The influence of phospholipids self-assembly on SHIPEs formation was investigated by evaluating the microstructures, particle size, rheological properties, and water distribution. Results demonstrated that the concentration and self-assembly behavior of phospholipids dominated the SHIPEs formation. Optimized SHIPEs with desirable gel properties contained 10 wt% krill oil in the oil phase at an 80 wt% oil phase level. Furthermore, these SHIPEs exhibited excellent performance in 3D printing applications. Hydrated phospholipids formed lamellar network at the oil-water interface, enhancing gel strength by crosslinking oil droplets. These findings shed light on the self-assembly of phospholipids during HIPEs formation and highlight the potential phospholipids-rich marine lipids in SHIPEs for functional food products development.

Antarctic krill (Euphausia superba) oil high internal phase emulsions improved the lipid quality and gel properties of surimi gel.

In the study, high internal phase emulsions (HIPEs) prepared from Antarctic krill oil (AKO) were added into surimi and the effects on gel properties, lipid quality and stability were investigated. It is found that HIPEs-added groups exhibited higher gel strength and lower cooking loss than Oil-added counterparts. HIPEs-added groups had higher proportion of capillary water, and microstructure of HIPEs-added gels showed fewer large voids and small size droplets. HIPEs-added groups also showed less pronounced myosin heavy chain band. HIPEs- and Oil-added gels showed > 3500 mg/kg EPA + DHA and 0.4-0.8 mg/kg astaxanthin, and most HIPEs-added groups had higher levels of them but lower TBARS values. Results suggest AKO-HIPEs could reduce the intervention by lipids on myosin crosslinking during gelation, and protect fatty acids and asxtanthin from oxidation due to oxygen-isolation led by their high accumulation. Thus, AKO-HIPEs can be applied to fortify ω-3 PUFA and maintain good gel properties in surimi product.

Effect of dietary krill oil supplementation on horse red blood cell membrane fatty acid composition and blood parameters.

Supplementation with marine-derived n-3 long-chain polyunsaturated fatty acids (LC PUFAs), eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3) is linked to beneficial health effects in both humans and horses. Krill oil (KO), which is extracted from the Antarctic krill (Euphausia superba), is well documented as a safe and biologically available dietary supplement in humans and several animal species, but there is a lack of documentation regarding its effect as a dietary ingredient for horses. The objective of this study was to test whether KO as a dietary supplement had the ability to raise horse red blood cell (RBC) membrane EPA and DHA, expressed as the n-3 index. Five nonworking Norwegian cold-blooded trotter horse geldings (body weight [BW]: 567 ± 38 kg) were supplemented with KO (10 mL/100 kg BW) for 35 days in a longitudinal study. Blood samples were analysed for RBC membrane fatty acid (FA) profile, haematology and serum biochemistry every 7th day. KO was well accepted by all horses, and no adverse health effects were observed during the 35-day trial period. KO supplementation affected the RBC membrane FA profile by increasing the n-3 index from Day 0 to 35 (Day 0: 0.53% vs. Day 35: 4.05% of total RBC FAs). The observed increase in the sum of EPA and DHA (p < 0.001), total n-3 FAs (p < 0.001) and the reduction of n-6 FAs (p < 0.044) resulted in a lower n-6:n-3 ratio (p < 0.001) by Day 35 of KO supplementation. In conclusion, the RBC n-3 index was increased and the general n-6:n-3 ratio was decreased in horses receiving 35-day dietary KO supplementation.

Microplastics in Antarctic krill (Euphausia superba) from Antarctic region.

Pollution of microplastics (MPs) has become a potential threat to Antarctic marine ecosystems. However, the occurrence of MPs in Antarctic krill (Euphausia superba), a keystone species in Antarctic ecosystems, remains unclear. In this study, the abundance and characteristics of MPs were examined in Antarctic krill samples (n = 437) collected from two Antarctic regions. MPs were extracted using an alkali digestion method and analyzed using Fourier-transform infrared spectroscopy. The mean abundance of MPs in Antarctic krill samples from the South Shetland Islands (n = 355) and the South Orkney Islands (n = 82) were 0.29 ± 0.14 and 0.20 ± 0.083 items/individual, respectively. >90 % of MPs found in Antarctic krill were < 150 µm in size. Fibers represented 77 % and 87 % of the MPs in Antarctic krill samples from the South Shetland Islands and the South Orkney Islands, respectively. Black, blue, and red were the predominant colors of MPs in Antarctic krill, accounting for 32 %, 22 %, and 21 % of the total MPs, respectively. Seven polymer compositions were identified for the MPs in Antarctic krill, with the predominance of polyethylene (37 % of total MPs), followed by polypropylene (22 %) and polyester (21 %). To our knowledge, this is the first study to investigate the occurrence of MPs in Antarctic krill samples. The results of this study are important for evaluating the risks of MP exposure in Antarctic krill.

Two-Step Enzymolysis of Antarctic Krill for Simultaneous Preparation of Value-Added Oil and Enzymolysate.

Antarctic krill is a crucial marine resource containing plenty of high-valued nutrients. However, krill oil as a single product has been developed by the current solvent extraction with high cost. From the perspective of comprehensive utilization of Antarctic krill, this study proposed a novel two-step enzymolysis-assisted extraction in attempt to produce value-added oil and enzymolysate simultaneously. After two-step chitinase/protease hydrolysis, the lipid yield increased from 2.09% to 4.18%, reaching 112% of Soxhlet extraction. The method greatly improved the yields of main components while reducing the impurity content without further refining. After optimization, the oil contained 246.05 mg/g of phospholipid, 80.96 mg/g of free eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and 0.82 mg/g of astaxanthin. The by-product enzymolysate was abundant in water-soluble proteins (34.35 mg/g), oligopeptides (13.92 mg/g), amino acids (34.24 mg/g), and carbohydrates (5.79 mg/g), which was a good source of functional nutrients. In addition, both oil and enzymolysate showed high antioxidant capacity. This novel method could simultaneously provide oil and enzymolysate amounting for 58.61% of dried krill.

The Complex of Phycobiliproteins, Fucoxanthin, and Krill Oil Ameliorates Obesity through Modulation of Lipid Metabolism and Antioxidants in Obese Rats.

Phycobiliproteins, fucoxanthin, and krill oil are natural marine products with excellent activities. In the study, we prepared the complex of phycobiliproteins, fucoxanthin, and krill oil (PFK) and assessed the anti-obesity, lipid-lowering, and antioxidant activities in high-fat diet rats. The results showed that the rats significantly and safely reduced body weight gain and regulated serum biochemical parameters at 50 mg/kg phycobiliproteins, 10 mg/kg fucoxanthin, and 100 mg/kg krill oil. Furthermore, the molecular mechanism study suggested that the complex of PFK confined the enzyme activities of lipid synthesis and enhanced antioxidant activity to improve obesity indirectly. The conclusions demonstrated that the complex of PFK has potent anti-obesity and hypolipidemic effects which have potential use as a natural and healthy food and medicine for anti-obesity and lowering blood lipids in the future.

Local Application of Krill Oil Accelerates the Healing of Artificially Created Wounds in Diabetic Mice.

Diabetes mellitus (DM) impairs the wound healing process, seriously threatening the health of the diabetic population. To date, few effective approaches have been developed for the treatment of diabetic wounds. Krill oil (KO) contains bioactive components that have potent anti-inflammatory and anti-oxidative activities. As prolonged inflammation is a crucial contributor to DM-impaired wound healing, we speculated that the local application of KO would accelerate diabetic wound healing. Therefore, KO was applied to artificially created wounds of type 2 diabetic mice induced by streptozotocin and high-fat diet. The diabetic mice had a delayed wound healing process compared with the non-diabetic control mice, with excessive inflammation, impaired collagen deposition, and depressed neovascularization in the wound area. These effects were dramatically reversed by KO. In vitro, KO blocked the TNF-α-induced macrophage inflammation, fibroblast dysfunction, and endothelial angiogenic impairment. The present study in mice suggests that KO local application could be a viable approach in the management of diabetic wounds.

Administration of krill oil extends lifespan of fish Nothobranchius guentheri via enhancement of antioxidant system and suppression of NF-κB pathway.

Krill oil (KO) extracted from Antarctic krill (Euphausia superba) mainly comprises phospholipids and triglycerides. KO has been shown to prolong the median lifespan of the nematode Caenorhabditis elegans, but to shorten the lifespan of long-lived F1 mice; therefore, it remains controversial over the life-extending property of KO. In this study, we clearly demonstrated that dietary intake of KO extended both the mean and maximum lifespans of aged male Nothobranchius guentheri (p < 0.05), reduced the accumulation of lipofuscin (LF) (p < 0.05) in the gills and senescence-associated ß-galactosidase (SA-ß-Gal) (p < 0.05) in the caudal fins, and lowered the levels of protein oxidation (p < 0.05), lipid peroxidation (p < 0.01), and reactive oxygen species (ROS) (p < 0.01) in the muscles and livers, indicating that KO possesses rejuvenation and anti-aging activity. We also showed that KO enhanced the activities of antioxidant enzymes catalase (CAT) (p < 0.05), superoxide dismutase (SOD) (p < 0.05), and glutathione peroxidase (GPX) (p < 0.05) in aged male N. guentheri. In addition, KO administration effectively reversed histological lesions including inflammatory cell infiltration and structural collapse in the muscles and livers of aged N. guentheri and suppressed the nuclear factor kappa-B (NF-κB) signaling pathway (p < 0.05), a master regulator of inflammation. Altogether, our study indicates that KO has anti-aging and rejuvenation property. It also suggests that KO exerts its anti-aging and rejuvenation effects via enhancement of the antioxidant system and suppression of the NF-κB signaling pathway.

Preparation, Characterization, and Mechanism of Antifreeze Peptides from Defatted Antarctic Krill (Euphausia superba) on Lactobacillus rhamnosus.

Defatted Antarctic krill powder is the main by-product in the manufacturing of krill oil. Exploring a high value-added approach for utilizing this protein-rich material has received much attention in research and industry. Given this, the preparation and primary characterization of antifreeze peptides from defatted Antarctic krill (AKAPs) were carried out in this study. The cryoprotective effect of AKAPs on Lactobacillus rhamnosus ATCC7469 was also investigated. The results showed that Protamex was the optimum protease for AKAP preparation from defatted Antarctic krill. AKAPs were found to be rich in short peptides, with the MW ranging from 600 to 2000 Da (69.2%). An amino acid composition analysis showed that AKAPs were rich in glutamic acid (18.71%), aspartic acid (12.19%), leucine (7.87%), and lysine (7.61%). After freezing, the relative survival rate of Lactobacillus rhamnosus in the 1.0 mg/mL AKAP-treated group (96.83%) was significantly higher than in the saline group (24.12%) (p < 0.05). AKAPs also retarded the loss of acidifying activity of L. rhamnosus after freezing. AKAPs showed even better cryoprotective activity than three commercial cryoprotectants (sucrose, skim milk, and glycerol). In addition, AKAPs significantly alleviated the decrease in ß-galactosidase and lactic dehydrogenase activities of L. rhamnosus (p < 0.05). Furthermore, AKAPs effectively protected the integrity of L. rhamnosus cell membranes from freezing damage and alleviated the leakage of intracellular substances. These findings demonstrate that AKAPs can be a potential cryoprotectant for preserving L. rhamnosus, providing a new way to use defatted Antarctic krill.