Resistant starch-enriched brown rice exhibits prebiotic properties and enhances gut health in obese mice.

Resistant starch serves as a prebiotic in the large intestine, aiding in the maintenance of a healthy intestinal environment and mitigating associated chronic illnesses. This study aimed to investigate the impact of resistant starch-enriched brown rice (RBR) on intestinal health and functionality. We assessed changes in resistant starch concentration, structural alterations, and branch chain length distribution throughout the digestion process using an in vitro model. The efficacy of RBR in the intestinal environment was evaluated through analyses of its prebiotic potential, effects on intestinal microbiota, and intestinal function-related proteins in obese animals fed a high-fat diet. RBR exhibited a higher yield of insoluble fraction in both the small and large intestines compared to white and brown rice. The total digestible starch content decreased, while the resistant starch content significantly increased during in vitro digestion. Furthermore, RBR notably enhanced the growth of four probiotic strains compared to white and brown rice, displaying higher proliferation activity than the positive control, FOS. Notably, consumption of RBR by high-fat diet-induced obese mice suppressed colon shortening, increased Bifidobacteria growth, and improved intestinal permeability. These findings underscore the potential prebiotic and gut health-promoting attributes of RBR, offering insights for the development of functional foods aimed at preventing gastrointestinal diseases.

Effects of myofibril-palatinose conjugate as a phosphate substitute on meat emulsion quality.

The objective of this study was to investigate a replacement for phosphate in meat products. Protein structural modification was employed in this study, and grafted myofibrillar protein (MP) with palatinose was added to meat emulsion without phosphate. Here, 0.15% of sodium polyphosphate (SPP) was replaced by the same (0.15%) concentration and double (0.3%) the concentration of grafted MP. Although the thermal stability was decreased, the addition of transglutaminase could increase stability. The rheological properties and pH also increased with the addition of grafted MP and transglutaminase. The addition of grafted protein could be perceived by the naked eye by observing a color difference before cooking, but it was not easy to detect after cooking. The cooking loss, emulsion stability, water holding capacity, lipid oxidation, and textural properties improved with the addition of grafted MP. However, the excessive addition of grafted MP and transglutaminase was not recommended to produce a high quality of phosphate replaced meat emulsion, and 0.15% was identified as a suitable addition ratio of grafted MP.

Methods to Isolate Muscle Stem Cells for Cell-Based Cultured Meat Production: A Review.

Cultured meat production relies on various cell types, including muscle stem cells (MuSCs), embryonic stem cell lines, induced pluripotent cell lines, and naturally immortalized cell lines. MuSCs possess superior muscle differentiation capabilities compared to the other three cell lines, making them key for cultured meat development. Therefore, to produce cultured meat using MuSCs, they must first be effectively separated from muscles. At present, the methods used to isolate MuSCs from muscles include (1) the pre-plating method, using the ability of cells to adhere differently, which is a biological characteristic of MuSCs; (2) the density gradient centrifugation method, using the intrinsic density difference of cells, which is a physical characteristic of MuSCs; and (3) fluorescence- and magnetic-activated cell sorting methods, using the surface marker protein on the cell surface of MuSCs, which is a molecular characteristic of MuSCs. Further efficient and valuable methods for separating MuSCs are expected to be required as the cell-based cultured meat industry develops. Thus, we take a closer look at the four methods currently in use and discuss future development directions in this review.

The effects of different extraction methods on essential oils from orange and tangor: From the peel to the essential oil.

Citrus fruits are largely consumed due to their unique and pleasant aromas. Citrus hybrids have been developed to enhance their flavors and bioactivities. Citrus aroma depends on the composition of the volatile compounds in citrus essential oils (CEOs), which are mostly located in the peels. During the extraction of CEOs, a specific series of chemical reactions occurred depending on the extraction methods (CP, cold pressing; HD, hydrodistillation), leading to variations in the composition of volatile compounds. In this study, the orange and the tangor which is a hybrid between C. reticulata × C. sinensis were investigated to compare the changes in volatile compounds based on the extraction methods. Results showed that the CP-specific volatile compounds were sesquiterpenes, oxygenated monoterpenes, and fatty acid derivatives, while the HD-specific volatile compounds were terpinyl cation derivatives, limonene, and 4-vinylguaiacol. On the other hand, the contents of some volatile compounds ((E)-ocimene, α-terpinene, and α-terpinolene) were affected by the Citrus species rather than by the extraction methods. In particular, during HD, terpinene-4-ol and 4-vinylguiacol, known as off-flavor compounds in citrus juice, were formed more abundantly in the orange than in the tangor. In conclusion, these results provide comprehensive data on essential oils, especially those derived from oranges and tangors, for selecting the appropriate extraction method for obtaining a higher yield and quality of citrus flavor.

Effect of Crude Polysaccharides from Ecklonia cava Hydrolysate on Cell Proliferation and Differentiation of Hanwoo Muscle Stem Cells for Cultured Meat Production.

Ecklonia cava, a brown seaweed native to the East Asian coast, is known for its unique composition, including polysaccharides, polyphenols, and phlorotannins. Fucoidan is a sulfated polysaccharide widely used as a functional ingredient in foods. This study obtained crude polysaccharides (ECC_CPS) from E. cava celluclast enzymatic hydrolysate using ethanol precipitation. ECC_CPS increased cell viability during the proliferation of Hanwoo muscle satellite cells (HMSCs). The effect of ECC_CPS on the expression of proliferation-related markers was confirmed as MYF5 and MYOD expression significantly increased, whereas PAX7 expression was maintained. The evaluation of cell migration activity has a major impact on cell proliferation and differentiation, and the cell migration index significantly increased with ECC_CPS treatment (p < 0.01). This was related to the HGF/MET pathway and FAK pathway. Treatment with ECC_CPS promoted differentiation at the cell differentiation stage, thereby increasing the expression of differentiation markers, such as MYH2, MYH7, and MYOG (p < 0.001 or p < 0.01). Therefore, our findings imply that crude polysaccharide obtained from E. cava can be an additive ingredient that enhances the proliferation and differentiation of muscle satellite cells used in the manufacture of cultured meat products.

Glyoxal-derived advanced glycation end products (GO-AGEs) with UVB critically induce skin inflammaging: in vitro and in silico approaches.

Advanced glycation end products (AGEs) have potential implications on several diseases including skin inflammation and aging. AGEs formation can be triggered by several factors such as UVB, glyoxal and methylglyoxal etc. However, little attention has been paid to glyoxal-derived AGEs (GO-AGEs) and UVB-induced skin inflammaging, with none have investigated together. This study aimed to investigate the possible role of GO-AGEs and UVB in skin inflammaging focusing on revealing its molecular mechanisms. The effects of GO-AGEs in the presence or absence of UVB were studied by using enzyme linked immunosorbent assay, western blotting, qPCR, flow cytometry and in silico approaches. In HaCaT cells, GO-AGEs in the presence of UVB irradiation (125 mJ/cm2) dramatically enhanced the release of different pro-inflammatory cytokines (IL-1ß, IL-6, and TNF-α) with further activation of RAGE signaling pathways (NF-κB, COX 2, and IL- 1ß) and increased oxidative stress also noticed in NHEK cells. In NHDF cells, extracellular matrix disruption noted via increasing matrix metalloproteinase release and decreasing collagen type 1 and SIRT1 expression. Besides that, the docking scores obtained from the molecular docking study support the above-mentioned results. This study strongly suggests the pivotal role of GO-AGEs in skin inflammaging and illuminates novel molecular pathways for searching most effective and updated anti-aging therapy.

Effects of Natural Extract Mixtures on the Quality Characteristics of Sausages during Refrigerated Storage.

Owing to the residual toxicity and adverse health effects of chemical preservatives, there is an increasing demand for using natural preservatives in food. Although many natural extracts have been evaluated, research on their antibacterial effects remains insufficient. Therefore, this study aimed to explore the possibility of developing Psidium guajava, Ecklonia cava, and Paeonia japonica (Makino) Miyabe & Takeda extracts as natural food preservatives. Further, the effect of mixing these extracts on microbial growth and quality was evaluated during the refrigeration of sausages. Optimal mixing ratios were determined based on the minimum inhibitory and bactericidal concentrations of each mixed extract against the Listeria monocytogenes, Salmonella spp. and Escherichia coli. D-optimal mixing design optimization tool was further used to obtain an optimum mixing ratio of Formulation 1 (F1). The antibacterial activity of F1 increased with increasing concentration, with similar activities at 0.5% and 1%. The sausages with synthetic or natural preservatives showed significantly lower lipid oxidation than those of the control and grapefruit extract-treated sausages after 4 wk of refrigeration. Total plate counts were observed only in the control and treatment groups stored for 3 wk, and no significant effect of ascorbic acid was observed. Compared to the other samples, sausages with added natural extracts showed the highest overall acceptability scores initially and after 4 wk. Therefore, similar amounts of grapefruit seed and natural extracts had the same effect on microbiological analysis and lipid rancidity during sausage storage. Hence, this mixture can serve as a potential natural preservative in meat products.

The Antioxidant Activity of Undaria pinnatifida Sporophyll Extract Obtained Using Ultrasonication: A Focus on Crude Polysaccharide Extraction Using Ethanol Precipitation.

Undaria pinnatifida, a marine biological resource from which antioxidants such as polysaccharides can be obtained, is primarily distributed in the coastal areas of East Asia. Reactive oxygen species (ROS) are essential for physiological processes; however, excess ROS levels in the body result in cellular oxidative damage. Several extraction methods exist; however, factors such as long extraction times and high temperatures degrade polysaccharides. Therefore, this study aimed to increase the yield of U. pinnatifida sporophyll extract (UPE), a U. pinnatifida byproduct, using ultrasonication, an environmentally friendly extraction method, and identify UPE components with antioxidant activity. UPE_2, 4, 6, and 8 extracts were obtained at extraction times of 2, 4, 6, and 8 h, respectively. UPE_8 had the highest yield (31.91%) and polysaccharide (69.22%), polyphenol, (8.59 GAE µg/mg), and fucoxanthin contents (2.3 µg/g). UPE_8 showed the greatest protective and inhibitory effects on ROS generation in H2O2-damaged Vero cells. Ethanol precipitation of UPE_8 confirmed that UPE_8P (precipitate) had superior antioxidant activity in Vero cells compared to UPE_8S (supernatant). UPE_8P contained a large amount of polysaccharides, a major contributor to the antioxidant activity of UPE_8. This study shows that UPE_8 obtained using ultrasonication can be a functional food ingredient with excellent antioxidant activity.

CLK2 in GABAergic neurons is critical in regulating energy balance and anxiety-like behavior in a gender-specific fashion.

Introduction: Cdc2-like kinase (CLK2) is a member of CLK kinases expressed in hypothalamic neurons and is activated in response to refeeding, leptin, or insulin. Diet-induced obesity and leptin receptor-deficient db/db mice lack CLK2 signal in the hypothalamic neurons. The neurotransmiter gamma-aminobutyric acid (GABA) is among the most prevalent in the central nervous system (CNS), particularly in the hypothalamus. Given the abundance of GABA-expressing neurons and their potential influence on regulating energy and behavioral homeostasis, we aimed to explore whether the deletion of CLK2 in GABAergic neurons alters energy homeostasis and behavioral and cognitive functions in both genders of mice lacking CLK2 in Vgat-expressing neurons (Vgat-Cre; Clk2loxP/loxP) on chow diet. Methods: We generated mice lacking Clk2 in Vgat-expressing neurons (Vgat-Cre; Clk2loxP/loxP) by mating Clk2loxP/loxP mice with Vgat-IRES-Cre transgenic mice and employed behavior, and physiological tests, and molecular approaches to investigate energy metabolism and behavior phenotype of both genders. Results and discussion: We showed that deletion of CLK2 in GABAergic neurons increased adiposity and food intake in females. The mechanisms behind these effects were likely due, at least in part, to hypothalamic insulin resistance and upregulation of hypothalamic Npy and Agrp expression. Besides normal insulin and pyruvate sensitivity, Vgat-Cre; Clk2loxP/loxP females were glucose intolerant. Male Vgat-Cre; Clk2loxP/loxP mice showed an increased energy expenditure (EE). Risen EE may account for avoiding weight and fat mass gain in male Vgat-Cre; Clk2loxP/loxP mice. Vgat-Cre; Clk2loxP/loxP mice had no alteration in cognition or memory functions in both genders. Interestingly, deleting CLK2 in GABAergic neurons changed anxiety-like behavior only in females, not males. These findings suggest that CLK2 in GABAergic neurons is critical in regulating energy balance and anxiety-like behavior in a gender-specific fashion and could be a molecular therapeutic target for combating obesity associated with psychological disorders in females.

Structural, physicochemical, and immune-enhancing properties of edible insect protein isolates from Protaetia brevitarsis larvae.

Edible insects are promising future food resources globally. Herein, the structural, physicochemical, and bio-functional properties of edible insect protein isolates (EPIs) extracted from Protaetia brevitarsis larvae were investigated. The results showed that EPIs have a high total essential amino acid content; moreover, ß-sheet is the major secondary protein structure. The EPI protein solution was highly soluble and electrically stable and did not aggregate easily. In addition, EPIs exhibited immune-enhancing properties; EPI treatment of macrophages induced the activation of macrophages and consequently promoted the production of pro-inflammatory mediators (NO, TNF-α, and IL-1ß). Moreover, macrophage activation of EPIs was confirmed to occur through the MAPK and NF-κB pathways. In conclusion, our results suggest that the isolated P. brevitarsis protein can be fully utilized as a functional food material and alternative protein source in the future food industry.

Fucoidan from Sargassum autumnale Inhibits Potential Inflammatory Responses via NF-κB and MAPK Pathway Suppression in Lipopolysaccharide-Induced RAW 264.7 Macrophages.

Fucoidans are sulfate-rich polysaccharides with a wide variety of beneficial biological activities. The present study aimed to highlight the anti-inflammatory activity of fucoidan from the brown seaweed Sargassum autumnale (SA) against lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells. Among the isolated fucoidan fractions, the third fraction (SAF3) showed a superior protective effect on LPS-stimulated RAW 264.7 cells. SAF3 inhibits nitric oxide (NO) production and expression of prostaglandin E-2 (PGE2) via downregulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2) expression in LPS-induced RAW 26.7 cells. SAF3 treatment decreased pro-inflammatory cytokines IL-1ß, TNF-α, and IL-6 expression in LPS-induced cells. LPS stimulation activated NF-κB and MAPK signaling cascades in RAW 264.7 cells, while treatment with SAF3 suppressed them in a concentration-dependent manner. Existing outcomes confirm that SAF3 from S. autumnale possesses potent anti-inflammatory activity and exhibits good potential for application as a functional food ingredient or for the treatment of inflammation-related disorders.

LRP1 mediates leptin transport by coupling with the short-form leptin receptor in the choroid plexus.

Adipocyte-derived leptin enters the brain to exert its anorexigenic action, yet its transport mechanism is poorly understood. Here we report that LRP1 (low-density lipoprotein receptor-related protein-1) mediates the transport of leptin across the blood-CSF barrier in Foxj1 expressing cells highly enriched at the choroid plexus (ChP), coupled with the short-form leptin receptor, and LRP1 deletion from ependymocytes and ChP cells leads to leptin resistance and hyperphagia, causing obesity. Thus, LRP1 in epithelial cells is a principal regulator of leptin transport in the brain.

Structural characteristics of resistant starch-enriched rice during digestion and its effects on gut barrier function in high-fat induced obese mice.

Dietary supplementation with indigestible carbohydrates is known to improve the gut environment and prevent obesity and inflammatory diseases by modulating the gut microbiota. In previous work, we established a method for the production of resistant starch (RS)-enriched high-amylose rice (R-HAR) using citric acid. The present study aimed to evaluate changes in structural characteristics during digestion of R-HAR and its effects on the gut health. A three-step in vitro digestion and fermentation model was used, then, RS content, scanning electron microscopy, and branch chain length distribution were analyzed during in vitro digestion. During the digestion of R-HAR, the RS content increased, and the structure was predicted to have a greater impact on the gut microbiota and gut environment. To study the intestinal health effects of R-HAR, its anti-inflammatory and gut barrier integrity activities were assayed in HFD-induced mice. Intake of R-HAR suppressed colonic shortening and inflammatory responses induced by HFD. Furthermore, R-HAR exhibited gut barrier protective activity with an increase in tight junction protein levels. We determined that R-HAR may be a potentially beneficial intestinal environment improver, which may have various implications in the food industry as rice.

Effects of Blanching Methods on Nutritional Properties and Physicochemical Characteristics of Hot-Air Dried Edible Insect Larvae.

Global meat consumption is increasing worldwide, however, supply remains lacking. Several alternative protein sources, such as cultured meat, plant-based protein production, and edible insects, have been proposed to overcome this shortage. Interestingly, edible insects are characterized by superior digestive and absorptive qualities that make them the ideal replacement for traditional protein production. This study aims to further the processing ability of insect protein by investigating the effects of various pre-treatment methods, such as blanching (HB), roasting (HR), and superheated steam (HS), on the nutritional properties and physicochemical characteristics of proteins extracted from Hermetia illucens larvae. The drying rate, pH value, color analysis, amino and fatty acid profile, as well as bulk density, shear force, and rehydration ratios of the above pre-treatment methods, were explored. HS was found to have the highest drying rate and pH value analysis showed that HB and HS samples have significantly higher values compared to the other modalities. Raw edible insects had the highest value in the sum of essential amino acid (EAA) and EAA index when compared to EAAs. HB and HS showed significantly lower bulk density results, and HS showed the highest shear force and the highest value in rehydration ratio, regardless of immersion time. Therefore, taking the above results together, it was found that blanching and superheated steam blanching pre-treatment were the most effective methods to improve the processing properties of H. illucens after hot-air drying.

Fucoidan from Sargassum thunbergii obtained via step gradient ethanol precipitation indicate potential anti-obesity and anti-hepatic steatosis in vitro 3T3-L1 and HepG2 cells and in vivo high-fat diet-induced obesity mice.

This study investigated the potential lipid inhibitory and anti-obesity effects of compounds derived from Sargassum thunbergii in vitro and in vivo. We prepared a Celluclast-assisted hydrolysate from Sargassum thunbergii (STC) and three fractional ethanol precipitates (STCF1, STCF2, STCF3). We investigated their proximate composition, and anti-obesity effects in vitro and in vivo. STC and STCFs all significantly reduced intracellular lipid accumulation in PA-treated 3T3-L1 and HepG2 cells. STC, STCF1, and STCF3 had profound anti-obesity effects on high fat diet (HFD)-fed obesity model mice. Oral administration of STC, STCF1, and STCF3 significantly reduced body weight and white adipose tissue (WAT) mass. Furthermore, serum lipid levels were significantly decreased. Additionally, adipose specific hormone levels (adiponectin and fibroblast growth factor-21 (FGF-21)) were significantly decreased, and serum insulin levels were also decreased by STC, STCF1, and STCF3 treatment. A mechanistic study revealed that the adipogenesis and lipolysis associated proteins in epididymal adipose tissue, and free fatty acid oxidation in liver tissues were effectively regulated by STC, STCF1, and STCF3. Overall, our findings show the potent anti-obesity effects of STC, STCF1, and STCF3, achieved by regulation of adipogenesis, lipolysis, and the fatty acid oxidation pathway in HFD-treated obesity model mice.

Peptides inhibiting angiotensin-I-converting enzyme: Isolation from flavourzyme hydrolysate of Protaetia brevitarsis larva protein and identification.

Many angiotensin-I-converting enzyme (ACE) inhibitory peptides are used to prevent and manage hypertension. In this study, ACE inhibitory peptides were isolated from an insect protein that is attracting attention for it potential antihypertensive activity. Protaetia brevitarsis larva protein was enzymatically hydrolyzed by Flavourzyme®, and the hydrolysate was shown to inhibit ACE. Subsequent fractionation, using ultrafiltration and gel permeation chromatography followed by liquid chromatography-tandem mass spectrometry analysis, identified four previously unknown peptides with significant ACE inhibition characteristics (Ser-Tyr, Pro-Phe, Tyr-Pro-Tyr, and Trp-Ile). The highest inhibition activity observed for Trp-Ile. These peptides stimulated production of NO in human umbilical vein endothelial cells and, based on molecular docking analysis, exerted their inhibitory effects via hydrogen bonding with the ACE receptor active site. Thus, the identified peptides can be considered as promising candidates for ACE inhibition and have potential to be used as functional food ingredients.

Effect of Grafted Insect Protein with Palatinose on Quality Properties of Phosphate-Free Meat Emulsion.

Due to concerns about the negative effects of phosphate on human health, the development of phosphate substitutes is an active area of research. Among the various methods, the structural modification of proteins has previously been established. In this study, we used grafting technology. Extracted insect protein was grafted with palatinose (GI), and 0.1 and 0.15% of GI were added to a phosphate-free meat emulsion mixed with 0.1% of eggshell powder (ES). The pH, myofibrillar protein solubility, and apparent viscosity increased with the addition of GI and ES (p < 0.05). Color values were also affected by GI and ES addition (decreased CIE L* and CIE a* and increased CIE b*; p < 0.05), while cooking loss was only improved by the addition of ES and not GI. Although the total fluid separated more than negative control (p < 0.05), the addition of ES improved emulsion stability and total expressible fluid separation and the fat separation reduced with addition of GI and ES (p < 0.05). Lipid oxidation was inhibited by the addition of GI and ES (p < 0.05). Moreover, the protein molecular weight distribution under 20 kDa was modified by the addition of GI, and the hardness and springiness of treatments decreased. In conclusion, the addition of GI and ES might be used to improve cooking loss, emulsion stability, and antioxidants, while the textural properties should be further researched.

Isolation and Characterization of Efficient Active Compounds Using High-Performance Centrifugal Partition Chromatography (CPC) from Anti-Inflammatory Activity Fraction of Ecklonia maxima in South Africa.

Ecklonia maxima is a brown seaweed, which is abundantly distributed in South Africa. This study investigated an efficient approach using high-performance centrifugal partition chromatography (HPCPC), which has been successfully developed for the isolation and purification of phlorotannins, eckmaxol, and dieckol from the ethyl acetate fraction of E. maxima (EEM). We evaluated EEM for its inhibitory effect against lipopolysaccharide (LPS)-induced inflammatory responses in zebrafish embryos. The separation of eckmaxol and dieckol from samples of EEM using HPCPC was found to be of high purity and yield under an optimal solvent system composed of n-hexane:ethyl acetate:methanol:water (2:7:3:7, v/v/v/v). To evaluate the anti-inflammatory efficacy of EEM containing active compounds, zebrafish embryos exposed to LPS were compared with and without EEM treatment for nitric oxide (NO) production, reactive oxygen species (ROS) generation, and cell death two days after fertilization. These evaluations indicate that EEM alleviated inflammation by inhibiting cell death, ROS, and NO generation induced by LPS treatment. According to these results, eckmaxol and dieckol isolated from brown seaweed E. maxima could be considered effective anti-inflammatory agents as pharmaceutical and functional food ingredients.

Effects of Loquat (Eriobotrya japonica Lindl.) Leaf Extract with or without Ascorbic Acid on the Quality Characteristics of Semi-Dried Restructured Jerky during Storage.

Deterioration of jerky during storage is a major concern; this is usually combated with natural or synthetic antioxidants. This study aimed to evaluate the quality characteristics of semi-dried restructured jerky with and without loquat leaf extract (LE) powder and ascorbic acid (AA) during storage for 180 days. The jerkies were formulated with 0%, 0.15%, and 0.3% LE and/or 0.05% AA (Control, no antioxidant; AA, 0.05% AA; LE 0.15, 0.15% loquat LE; LE 0.15-AA, 0.15% loquat LE+0.05% AA; LE 0.3, 0.3% loquat LE; LE0.3-AA, 0.3% loquat LE+0.05% AA). LE is a phenolic compound, whose 1,1-diphenyl-2-picrylhydarzyl radical scavenging activity and metal chelating activity were found to be higher than AA. All antioxidant combinations having higher LE concentration and containing AA were effective in delaying protein and lipid oxidation compared to the control or AA. At the end of storage period, LE 0.15-AA and AA had higher CIE a* and lower shear force than the control. Therefore, the combination of 0.15% LE and 0.05% AA can result in reduced protein and lipid oxidation without any negative effect on the quality characteristics of semi-dried restructured jerky.

Antioxidant potential of low molecular weight fucoidans from Sargassum autumnale against H2O2-induced oxidative stress in vitro and in zebrafish models based on molecular weight changes.

In this study, we investigated the potential antioxidant abilities of low-molecular weight fucoidans from enzyme-assisted hydrolysates of Sargassum autumnale, based on molecular weight changes, in vitro and in vivo. The yield and free radical-scavenging activities of enzyme-assisted hydrolysates of S. autumnale were screened. The protamex-assisted hydrolysate of S. autumnale (SAP) presented the highest yield and 2,2-diphenyl-1-picrylhydrazyl (DPPH)-scavenging activity; therefore, it was chosen for fucoidan purification. Three fucoidan fractions were observed in SAP, and their antioxidant activity was assessed. Fucoidan fraction 3 of protamex-assisted hydrolysate of S. autumnale (SAPF3) offered significant protection against H2O2-induced oxidative stress, and was structurally and physically similar to commercial fucoidan. Fucose and low-molecular weight fucoidans were highly concentrated in SAPF3. The results of our study show that SAPF3, a low-molecular weight fucoidan from S. autumnale, possesses strong antioxidant properties and may be an effective alternative to antioxidant agents in the functional food industry.