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In food processing, freezing is vital in food preservation, specifically in preserving food quality, nutrition contents, and shelf-life. This study investigated the effects of different freezing equipment [such as cells alive system freezer (CAS) equipped with a weakly oscillating magnetic field (OMF), liquid nitrogen freezers (LNF), Air blow freezer (AF), and home freezer (HF)] on the preservation of giant tiger grouper [hybridized with giant grouper (Epinephelus fuscoguttatus) and tiger grouper (Epinephelus lanceolatus)] fillets with insight iaanto the changes in quality indexes and physicochemical properties of the fillets during the freezing process. This study showed that the CAS group could reduce the time it took for the sample to pass through the maximum icing crystal formation zone during freezing. It was determined by low-field pulsed nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) that the water migration and the formation of numerous tiny, uniformly dispersed ice crystals in the CAS group, while also defined by the tissue sections, revealed less damage to the muscle tissue of the fillet. Moreover, it also provides the fillets with better freezing loss, thawing loss, water holding capacity (WHC), and several satisfactory quality indexes (such as total volatile basic nitrogen (TVBN), total plate count (TPC), color (L*, a* and b* values), hardness and elasticity, etc.) within 4 weeks. This study's findings were expected to contribute to developing more effective and efficient freezing strategies for hybrid giant tiger grouper fillet preservation, thus enabling the production of high-quality products that meet the demands of consumers.

The effects of soaking milkfish fillet in 3% or 9% NaCl brines for 90 min at 4°C, and followed by processing with varying hydrostatic pressures (300, 400, 500, and 600 MPa) for 5 min on microbial quality and physicochemical properties were evaluated. After brine salting, the color of the fillet, the L* (lightness), W (whiteness), and ΔE (color difference) values increased with the increases in pressure, whereas the a* (redness) and b* (yellowness) values decreased, indicating that the fillet became brighter and whiter. Among them, 3% brine salting combined with pressures of 300 and 400 MPa groups had higher redness (a* value) and lower ΔE value compared to the higher pressure groups. Regarding the texture of the fillet, the hardness and chewiness of unsalted fish were significantly higher than that of brine salted fish under the same pressure, whereas the cohesiveness of the unsalted fillet was significantly lower than that of brine salted fillet. The results indicates that brine salting could make the instrumental texture of fish softer, which can compensate for the disadvantages of increased hardness and chewiness of the fillet caused by high-pressure processing. Brine salting combined with high pressure produced a significantly reducing effect on aerobic plate count (APC), psychrotrophic bacteria count (PBC), and total volatile basic nitrogen (TVBN) values of the fish as compared with that by brine salting or high pressure alone. Therefore, brine salting at a proper brine concentration (3%) and followed by high-pressure processing at 300 or 400 MPa for 5 min can improve or maintain a relatively good color and texture, as well as result in a synergistic bactericidal effect.

In this study, cereals with high starch content, including brown rice, corn, and buckwheat were pretreated by extrusion. The physicochemical properties of extruded-puffed cereals obtained from different extrusion conditions were analyzed herein. The puffed extrudates exhibited lower bulk density, higher water solubility and gelatinization as compared to untreated cereals. The FTIR-ATR results confirmed a decrease in the crystalline structure of extruded-puffed cereals. A higher Vmax/Km value was observed in the enzymatic saccharification of puffed extrudates that significantly improved hydrolysis rate and yield. Finally, the high-maltose syrup was produced via the enzymatic hydrolysis of extruded-puffed cereals at high substrate concentrations (20 %). After hydrolysis for 180 min at an enzyme substrate ratio (E/S ratio) of 0.2, the syrup with dextrose equivalent (DE) value of 63, 62, and 61 were obtained from extruded-puffed brown rice, corn, and buckwheat, respectively. Our results showed the potential of using extruded-puffed cereals for producing high-maltose syrup.

Vacuum frying (VF) is a selective technique for producing high-quality fried food that is mostly used on vegetables, fruits, and potato chips. It is rarely applied to the production of aquatic (especially fish) products. The purpose of this study is to explore whether VF technology can be applied to the preparation of dried silver herring products and to obtain the optimal VF conditions. The response surface methodology (RSM) was used to examine the factors affecting the quality of silver herring (Spratelloides gracilis) products after VF, namely temperature (75, 90, and 105 °C), duration (25, 35, and 45 min), and concentration (0, 15, and 30%) of maltose solution used to immerse the samples during pre-processing. The results indicated that VF temperatures had significant impacts on water activity (Aw), moisture content, yield, oil content, lightness (L* value), and colour difference (ÄE). The higher the VF temperature, the lower the Aw, moisture content, yield, and oil content of the product, but the higher the L* value and ΔE. Next, a longer VF duration resulted in higher oil content of the product. Maltose concentration was significantly and positively correlated with the yield and fracturability of the product. RSM analysis indicated that the optimal combination of processing conditions was a VF temperature of 105 °C, VF duration of 25 min, and maltose concentration of 27%. Under these VF conditions, the silver herring products had a moisture content of 3.91%, Aw of 0.198, oil content of 21.69%, L* value of 28.19, ΔE of 27.31, and fracturability of 359 g/s. In summary, vacuum frying technology is suitable for the preparation of dried silver herring products, and this study can provide the optimal processing conditions for seafood processors to obtain better quality.

Microwave-assisted induction heating (MAIH) is a composite microwave and induction heating to supply rapid and uniform heating of food. A recent study showed that the optimum MAIH heating condition for barramundi meat was 90 °C/110 s or 70 °C/130 s. This study examines whether the microwave-assisted induction heating (MAIH) technology (at 70 °C for 130 s or 90 °C for 110 s) can more effectively slow down the quality loss of barramundi meat during cold storage than the traditional boiling method (at 90 °C for 150 s). The results show that no microbial growth was observed in the three groups of heated barramundi meat samples during the 60 days of cold storage. However, the MAIH technology slowed down the increase in the total volatile basic nitrogen (TVBN) content more significantly than the boiling method. As the cold storage time increased, though, the L* (lightness), a* (redness), and W (whiteness) values decreased, while the b* (yellowness) and color difference (ΔE) values increased in the three treatment groups. However, the MAIH technology slowed down the decrease in the L*, a*, and W values more significantly, and produced a ΔE value smaller than the boiling method. Moreover, the MAIH technology ensured higher hardness and chewiness of the barramundi meat than the boiling method. Overall, the MAIH technology slowed down the quality loss of the barramundi meat and maintained better color and texture during cold storage.

The elderly population in developed countries has increased rapidly in recent years; the elderly may be at greater risk of protein deficiency due to dietary, socio-economic, dental, and physical restrictions. Therefore, to address the issue of protein deficiency in elderly people, the present study aimed to enhance the protein content of high-gluten flour noodles, an Asian staple food, by supplementing them with soybean protein isolate (SPI) powder. The effect of SPI addition (5–20%, w/w) on composition, quality, texture, physical and sensory properties, and glycemic index (GI) of high-gluten flour noodles was investigated. The noodles made only from high-gluten flour served as control. In comparison to control noodles, 20% SPI noodles showed a rise in protein and moisture content from 16.17% to 30.64% and 36.06 to 44.84%, respectively. The cooking yield and cooking loss increased with an increase in SPI concentration compared to control noodles. Color characteristics analysis revealed the decreasing trend in brightness and yellowness of SPI noodles with minimal L* and b* values at a 20% SPI concentration. The addition of SPI also resulted in a decrease in the hardness and tensile strength of the noodles. The sensory analysis showed that 5% SPI noodles were more similar to control noodles in terms of flavor, taste, and overall acceptability. Moreover, the addition of SPI to the noodles significantly decreased the GI of the noodles reaching the standard of low-GI food. The findings of the current study indicate that soy protein noodles, besides supplementing the desired nutrients, may also prevent the risk of diabetes in elderly people.

We assessed the microbial and chemical qualities and microbiomes of 14 mustard pickle products coded sequentially from A to N and sold in traditional Taiwanese markets. The results showed that the aerobic plate count and lactic acid bacteria count of commercially available mustard pickle products were 2.18–4.01 and Escherichia coli, Staphylococcus aureus, Salmonella spp., or Listeria monocytogenes were detected in any of the samples. Analysis of the chemical quality showed that the sulfite content of all samples exceeded 30 ppm, which is the food additive limit in Taiwan. Furthermore, the mean contents of eight biogenic amines in the mustard pickle product samples were below 48.0 mg/kg. The results of high-throughput sequencing showed that the dominant bacterial genera in sample A were Proteus spp. (25%), Vibrio (25%), and Psychrobacter (10%), in sample C they were Weissella (62%) and Lactobacillus (15%), in sample E it was Lactobacillus (97%), and in sample J it was Companilactobacillus (57%). Mustard pickle product samples from different sources contained different microbiomes. The dominant bacterial family was Lactobacillaceae in all samples except for sample A. In contrast, the microbiome of sample A mainly consisted of Morganellaceae and Vibrionaceae, which may have resulted from environmental contamination during storage and sales. The result of this work suggests it may be necessary to monitor sulfite levels and potential sources of bacterial contamination in mustard pickle products, and to take appropriate measures to rule out any public health risks.

The purpose of the study is to investigate the effects of brine salting and high-pressure processing (HPP) on the microbial inactivation and quality parameters of mackerel fillets. Mackerel fillets were immersed in 3% and 9% sodium chloride brine for 90 min at refrigerator temperature, and then treated at 300, 400, 500, and 600 MPa pressure for 5 min. The microbial counts and physicochemical qualities of the fish were examined. In comparison with fish fillets treated with brine or high pressure alone, those treated with the combination of brine salting and HPP showed significantly reduced aerobic plate count (APC) and psychrotrophic bacteria count (PBC). The hardness and chewiness of salt-brined fillets were obviously lower than those of the unsalted fillets under the same pressure condition. Thus, brine salting imparted mackerel fillets a softer texture, which compensated for the HPP-induced increased hardness and chewiness of the fillets. The L* (lightness) and ΔE (colour difference) values of the fillets increased with increasing pressure, with or without brine salting. Conversely, a* (redness) values decreased with increasing pressure. The samples treated with 3% brine in combination with 300 or 400 MPa pressure had a* values similar to those of the samples processed under similar HPP conditions alone but showed lower ΔE values than the other groups. Therefore, as a very high pressure would adversely affect the texture and colour of the fish fillets, this study suggests that immersion in an appropriate brine concentration (3%) and treatment with HPP at 400 MPa for 5 min improved or maintained the colour and texture relatively well and produced a synergistic bactericidal effect.

Chondroitin sulfate (ChS) is usually used as an oral nutraceutical supplement, and has been popular in Asia, Europe, and United States for many years. In this study, a potential and sustainable source of ChS from jumbo squid (Dosidicus gigas) cartilage was explored; ultrasound-assisted extraction (UAE) was used to extract ChS from jumbo squid cartilage. The result of mass transfer coefficients based on Fick’s law showed that UAE had higher mass transfer efficacy. The response surface methodology (RSM) combined with Box–Behnken design (BBD) was employed to evaluate the effects of the extraction parameters. The optimal conditions were extraction temperature of 52 °C, extraction time of 46 min, and NaOH concentration of 4.15%. The crude extract was precipitated by 50% ethanol, which obtained a purified ChS with 23.7% yield and 82.3% purity. The purified ChS measured by energy-dispersive X-ray spectroscopy (EDX) had a carbon to sulfur molar ratio of approximately 14:1. The FTIR, 1H, and 13C NMR confirmed jumbo squid ChS were present in the form of chondroitin-4-sulfate and chondroitin-6-sulfate, with a 4S/6S ratio of 1.62. The results of this study provide an efficient process for production and purification of ChS, and are significant for the development and utilization of ChS from jumbo squid cartilage in the nutrient food or pharmaceutical industries.

Refined cobia liver oil is a nutritional supplement (CBLO) that is rich in polyunsaturated fatty acids (PUFAs), such as DHA and EPA; however, PUFAs are prone to oxidation. In this study, the fabrication of chitosan-TPP-encapsulated CBLO nanoparticles (CS@CBLO NPs) was achieved by a two-step method, including emulsification and the ionic gelation of chitosan with sodium tripolyphosphate (TPP). The obtained nanoparticles were inspected by dynamic light scattering (DLS) and showed a positively charged surface with a z-average diameter of between 174 and 456 nm. Thermogravimetric analysis (TGA) results showed the three-stage weight loss trends contributing to the water evaporation, chitosan decomposition, and CBLO decomposition. The loading capacity (LC) and encapsulation efficiency (EE) of the CBLO loading in CS@CBLO NPs were 17.77–33.43% and 25.93–50.27%, respectively. The successful encapsulation of CBLO in CS@CBLO NPs was also confirmed by the Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques. The oxidative stability of CBLO and CS@CBLO NPs was monitored by FTIR. As compared to CBLO, CS@CBLO NPs showed less oxidation with a lower generation of hydroperoxides and secondary oxidation products after four weeks of storage. CS@CBLO NPs are composed of two ingredients that are beneficial for health, chitosan and fish oil in a nano powdered fish oil form, with an excellent oxidative stability that will enhance its usage in the functional food and pharmaceutical industries.

Fish gelatin and its hydrolysates exhibit a variety of biological characteristics, which include antihypertensive and antioxidant properties. In this study, fish gelatins were extracted from extrusion-pretreated tilapia scales, and then subjected to analyses to determine the physicochemical properties and antioxidant activity of the extracted gelatins. Our findings indicate that TSG2 (preconditioned with 1.26% citric acid) possessed the greatest extraction yield, as well as higher antioxidant activities compared with the other extracted gelatins. Hence, TSG2 was subjected to further hydrolyzation using different proteases and ultrafiltration conditions, which yielded four gelatin hydrolysates: TSGH1, TSGH2, TSGH3, and TSGH4. The results showed that TSGH4 (Pepsin + Pancreatin and ultrafiltration < 3000 Da) had a higher yield and greater antioxidant activity in comparison with the other gelatin hydrolysates. As such, TSGH4 was subjected to further fractionation using a Superdex peptide column and two-stage reverse-phase column HPLC chromatography, yielding a subfraction TSGH4-6-2-b, which possessed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity compared with the other fractions. Further LC-ESI/MS/MS analysis of TSGH4-6-2-b suggested two novel peptides (GYDEY and EPGKSGEQGAPGEAGAP), which could have potential as naturally-occurring peptides with antioxidant properties. These promising results suggest that these antioxidant peptides could have applications in food products, nutraceuticals, and cosmetics.

Intensive efforts have been undertaken in the fields of prevention, diagnosis, and therapy of lung cancer. Fucoidans exhibit a wide range of biological activities, which are dependent on the degree of sulfation, sulfation pattern, glycosidic branches, and molecular weight of fucoidan. The determination of oversulfation of fucoidan and its effect on anti-lung cancer activity and related signaling cascades is challenging. In this investigation, we used a previously developed fucoidan (SCA), which served as a native fucoidan, to generate two oversulfated fucoidan derivatives (SCA-S1 and SCA-S2). SCA, SCA-S1, and SCA-S2 showed differences in compositions and had the characteristic structural features of fucoidan by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) analyses. The anticancer properties of SCA, SCA-S1, and SCA-S2 against human lung carcinoma A-549 cells were analyzed in terms of cytotoxicity, cell cycle, Bcl-2 expression, mitochondrial membrane potential (MMP), expression of caspase-3, cytochrome c release, Annexin V/propidium iodide (PI) staining, DNA fragmentation, and the underlying signaling cascades. Our findings indicate that the oversulfation of fucoidan promotes apoptosis of lung cancer cells and the mechanism may involve the Akt/mTOR/S6 pathway. Further in vivo research is needed to establish the precise mechanism whereby oversulfated fucoidan mitigates the progression of lung cancer.

Abstract Histamine is the main causative agent of scombroid poisoning. However, unlike scombroid fish, histamine poisoning due to consumption of flying fish has never been reported. In this study, the white muscle of flying fish had high levels of free histidine at approximately 423.9 mg/100 g, and was inoculated with Staphylococcus xylosus Q2 isolated from dried flying fish at 5.0 log CFU/g and stored at −20 to 35°C to investigate histamine-related quality. The histamine contents quickly increased to higher than 50 mg/100 g in samples stored at 25 and 35°C within 12 h as well as stored at 15°C within 48 h. However, bacterial growth and histamine formation were controlled by cold storage of the samples at 4°C or below. Once the frozen flying fish samples stored at −20°C for 2 months were thawed and stored at 25°C after 24 h, histamine started to accumulate rapidly (>50 mg/100 g of fish). Therefore, flying fish muscle was a good substrate for histamine formation by bacterial histidine decarboxylation at elevated temperatures (>15°C) when it is contaminated with S. xylosus. In conclusion, since the improperly contaminated flying fish muscle with S. xylosus could lead to production of hazardous levels of histamine over time when stored at temperatures >15°C, the flying fish should be stored below 4 °C or below to control proliferation of S. xylosus, and TVBN and histamine production.

Fucoidans possess multiple biological functions including anti-cancer activity. Moreover, low-molecular-weight fucoidans are reported to possess more bioactivities than native fucoidans. In the present study, a native fucoidan (SC) was extracted from Sargassum crassifolium pretreated by single-screw extrusion, and three degraded fucoidans, namely, SCA (degradation of SC by ascorbic acid), SCH (degradation of SC by hydrogen peroxide), and SCAH (degradation of SC by ascorbic acid + hydrogen peroxide), were produced. The extrusion pretreatment can increase the extraction yield of fucoidan by approximately 4.2-fold as compared to the non-extruded sample. Among SC, SCA, SCH, and SCAH, the chemical compositions varied but structural features were similar. SC, SCA, SCH, and SCAH showed apoptotic effects on human lung carcinoma A-549 cells, as illustrated by loss of mitochondrial membrane potential (MMP), decreased B-cell leukemia-2 (Bcl-2) expression, increased cytochrome c release, increased active caspase-9 and -3, and increased late apoptosis of A-549 cells. In general, SCA was found to exhibit high cytotoxicity to A-549 cells and a strong ability to suppress Bcl-2 expression. SCA also showed high efficacy to induce cytochrome c release, activate caspase-9 and -3, and promote late apoptosis of A-549 cells. Therefore, our data suggest that SCA could have an adjuvant therapeutic potential in the treatment of lung cancer. Additionally, we explored that the Akt/mammalian target of rapamycin (mTOR) signaling pathway is involved in SC-, SCA-, SCH-, and SCAH-induced apoptosis of A-549 cells.

Fucoidans constitute a family of fucose-rich sulfated polysaccharides, which possess multiple characteristics, including antioxidant, antitumor, antivirus, anticoagulant, and anti-inflammatory properties. In addition, the incidence of colon cancer has risen rapidly worldwide. In the present study, fucoidan extracts were extracted from the Sargassum glaucescens (SG) pretreated by compressional-puffing, and four fucoidans (SG1-SG4) were obtained with different puffing conditions. It was found that SG4 possessed the highest extraction yield, relatively high cytotoxicity against human colon carcinoma HT-29 cells, and relatively low cytotoxicity to normal cells, as compared to the other extracted fucoidans. Moreover, SG4 caused cell cycle arrest of HT-29 cells at sub-G1, S, and G2/M phases. SG4 also induced HT-29 cellular apoptosis, as evidenced by the loss of mitochondrial membrane potential (MMP), increased cytochrome c release, activation of caspase-9 and -3, increased DNA fragmentation, and increased early and late apoptotic cells visualized by annexin V/propidium iodide (PI) assay. Additional biological experiments revealed that the Akt/mammalian target of rapamycin (mTOR)/S6 pathway is involved in SG4-induced apoptosis of HT-29 cells. These results clearly indicate that SG4 showed anti-colon cancer potential via the induction of cell cycle arrest and apoptosis, and thus may have a possible application as an adjuvant therapeutic agent in colon cancer treatment.

During the processing of mango, a huge amount of peel is generated, which is environmentally problematic. In the present study, a compressional-puffing process was adopted to pretreat the peels of various mango cultivars, and then the bioactive compounds of mango peels were extracted by water or ethanol. The phenolic compound compositions as well as the free radical-scavenging, anti-inflammatory, and antibacterial activities of water extract (WE) and ethanol extract (EE) from nonpuffed (NP) and compressional-puffed (CP) mango peels were further evaluated. It was found that compressional-puffing could increase the yield of extracts obtained from most mango varieties and could augment the polyphenol content of extracts from Jinhwang and Tainoung number 1 (TN1) cultivars. The WE and EE from TN1 exhibited the highest polyphenol content and the greatest free radical-scavenging activities among the mango cultivars tested. Seven phenolic compounds (gallic acid, pyrogallol, chlorogenic acid, p-hydroxybenzoic acid, p-coumaric acid, ECG, and CG) were detected in CPWE (compressional-puffed water extract) and CPEE (compressional-puffed ethanol extract) from TN1, and antioxidant stability of both CPWE and CPEE was higher than that of vitamin C. Further biological experiments revealed that CPEE from TN1 possessed the strongest anti-inflammatory and antibacterial activities, and thus it is recommended as a multibioactive agent, which may have applications in the food, cosmetic, and nutraceutical industries.

A new bioprocess to produce resveratrol-enriched rice wine was established and the effects of adding Polygonum cuspidatum root powder to rice wine fermentation were investigated. In this new process, piceid and resveratrol were extracted from P. cuspidatum roots to rice wine and piceid was converted to resveratrol by β-glucosidase during fermentation. After 10 days co-fermentation, rice wine with high levels of resveratrol was obtained, which contained ~14% (v/v) ethanol, 122 mg/L piceid, and 86 mg/L resveratrol. The resveratrol-enriched rice wine had enhanced antioxidant activity with significantly stronger 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric ion reducing power, and ferrous ion chelating capability. Ultrafiltration (UF) was employed in this study using hollow fibers to clarify the end product, increase shelf life without heat treatment, and maintain the quality of the phenolic compounds. The boiled and UF-treated rice wine were evaluated for ethanol, piceid, resveratrol, clarity, aerobic plate count, total acidity, pH, reducing sugars, and amino acids. The quality of the resveratrol-enriched rice wine was maintained after four weeks storage at normal refrigeration temperatures.

Gelatin has been broadly utilized in the food, pharmaceutical, photographic, cosmetic and packaging industries, and there is also huge potential for novel applications of gelatin in the fields of biotechnology and biomedicine. In the present study, we extracted gelatin from fish processing waste, i.e., scale of tilapia, by a combined method of extrusion-pretreatment and hot water extraction. The extrusion-pretreatment process increases the extraction yield of gelatin. Three gelatins (FS2: preconditioning with double-distilled water (ddH2O) before extrusion; FS12: preconditioning with citric acid solution before extrusion; FS14: preconditioning with acetic acid solution before extrusion) were obtained and all of them enhanced cell adhesion, cell growth, and wound healing in HaCaT cells and protected HaCaT cells from H2O2-induced cellular damage. Among FS2, FS12, and FS14, FS12 exhibited the most pronounced enhancement of cell adhesion, cell growth, and wound healing in HaCaT cells, and thus it may have potential as an effective natural raw material in cell therapies for cutaneous wounds and for reducing H2O2-induced oxidative damage of cells. In additional experiments, it was found that phosphorylations of Akt and mTOR are involved in the signaling pathway activated by FS2, FS12, and FS14 in HaCaT cells.

Fish gelatin hydrolysates have been shown to possess various biological activities due to their unique Gly-Pro-Y and Gly-X-Hyp sequences. In the current study, fish gelatin was extracted from non-extruded milkfish scale (FSG1) or extrusion-pretreated milkfish scale (FSG2); extracted gelatins were hydrolyzed with different combinations of Flavourzyme and Alcalase to give four different hydrolysates, namely: FSGH1 (FSG1 hydrolyzed with Flavourzyme), FSGH2 (FSG1 hydrolyzed with Alcalase + Flavourzyme), FSGH3 (FSG2 hydrolyzed with Flavourzyme), and FSGH4 (FSG2 hydrolyzed with Alcalase + Flavourzyme). The extrusion-pretreatment process enhanced the extraction yield of gelatin from fish scale. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared (FTIR) analyses showed the extracts FSG1 and FSG2 possessed characteristics of gelatin. Moreover, the physicochemical characteristics of FSGH1–FSGH4 were examined by analyses of their degree of hydrolysis, amino acid composition, UV spectrum, FTIR spectrum, molecular weight, and RP-HPLC profile. Additional biological functional analyses showed that all of the studied gelatin hydrolysates FSGH1–FSGH4 possessed antioxidant activity dose-dependently as revealed by DPPH scavenging, ABTS scavenging, and reducing power analyses. In addition, FSGH2 and FSGH4 showed higher angiotensin-I-converting enzyme (ACE)-inhibitory activity as compared to FSGH1 and FSGH3. Taken together, FSGH2 and FSGH4 showed high antioxidant activity and potent anti-ACE activity. Due to the potential antioxidant and antihypertensive properties of FSGH2 and FSGH4, further research is needed to explore their possible use as natural supplementary raw materials in food and nutraceutical products.

In this study, we extracted fucoidan from compressional-puffing-pretreated Sargassum crassifolium by hot water. The crude extract of fucoidan (SC) was degraded by various degradation reagents and four low-molecular-weight (LMW) fucoidans, namely SCO (degradation by hydrogen peroxide), SCA (degradation by ascorbic acid), SCOA (degradation by hydrogen peroxide + ascorbic acid), and SCH (degradation by hydrogen chloride) were obtained. The degradation reagents studied could effectively degrade fucoidan into LMW fucoidans, as revealed by intrinsic viscosity, agarose gel electrophoresis, and molecular weight analyses. These LMW fucoidans had higher uronic acid content and sulfate content than those of SC. It was found that SCOA exhibited antibacterial activity. All LMW fucoidans showed antioxidant activities as revealed by DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt), and FRAP (ferric reducing antioxidant power) methods. Biological experiments showed that SC and SCOA had relatively high activity for the reversal of H2O2-induced cell death in 3T3-L1 adipocytes, and SCOA showed the highest effect on attenuation of lipid accumulation in 3T3-L1 adipocytes. Therefore, for the LMW fucoidans tested, SCOA showed antibacterial activity and had a high fucose content, high sulfate content, high activity for the reversal of H2O2-induced cell death, and a marked effect on attenuation of lipid accumulation. It can thus be recommended as a natural and safe antibacterial and anti-adipogenic agent for food, cosmetic, and nutraceutical applications.

In this study, a compressional-puffing process (CPP) was used to pretreat Sargassum hemiphyllum (SH) and then fucoidan was extracted from SH by hot water. Three fucoidan extracts, namely SH1 (puffing at 0 kg/cm2); SH2 (puffing at 1.7 kg/cm2); and SH3 (puffing at 10.0 kg/cm2) were obtained, and their compositions and biological activities were evaluated. The results indicate that CPP increased the extraction yield, total sugar content, and molar ratios of sulfate/fucose of fucoidan and decreased molecular weight and impurities of fucoidan. The SH1–SH3 extracts exhibited characteristics of fucoidan as demonstrated by the analyses of composition, FTIR spectroscopy, NMR spectroscopy, and molecular weight. All SH1–SH3 extracts showed antioxidant activities. The SH1–SH3 extracts protected SH-SY5Y cells from 6-hydroxydopamine (6-OHDA)-induced apoptosis as illustrated by cell cycle distribution, cytochrome c release, activation of caspase-8, -9, and -3, and DNA fragmentation analyses. Additional experiments revealed that phosphorylation of Akt is involved in the opposing effects of SH1–SH3 on 6-OHDA-induced neurotoxicity. SH3 exhibited a relatively high extraction yield, the lowest levels of impurities, and was the most effective at reversing the 6-OHDA-induced neurotoxicity of SH-SY5Y cells among SH1–SH3, which taken together indicate that it may have potential as a candidate therapeutic agent for the preventive therapy of neurodegenerative diseases.

Fucoidan, a fucose-containing sulfated polysaccharide with diverse biological functions, is mainly recovered from brown algae. In this study, we utilized a compressional-puffing process (CPP) to pretreat Sargassum crassifolium (SC) and extracted fucoidans from SC by warm water. Three fucoidan extracts (SC1: puffing at 0 kg/cm2; SC2: puffing at 1.7 kg/cm2; and SC3: puffing at 6.3 kg/cm2) were obtained, and their composition, and antioxidant and neuroprotective activities were examined. The results suggest that CPP decreased the bulk density of algal samples, expanded the algal cellular structures, and eliminated the unpleasant algal odor. The extraction yields of fucoidans were increased and impurities of fucoidans were decreased by increasing the pressures used in CPP. The SC1–SC3 extracts displayed various characteristics of fucoidan as illustrated by the analyses of composition, Fourier transform infrared (FTIR) spectroscopy, and molecular weight. All three extracts SC1–SC3 showed antioxidant activity dose-dependently. Although both SC1 and SC2 possessed high and similar neuronal protective properties, SC2 showed a higher extraction yield, higher efficacy in the reversion of H2O2-induced cytotoxicity in rat pheochromocytoma PC-12 cells, and lower impurities compared with SC1, and thus SC2 is suggested as a good candidate for a therapeutic agent in the preventive treatment of neurodegenerative diseases.

Sargassum spp., a predominant seaweed speciesin Taiwan's coastal waters, exhibits a broad spectrum of bioactivities. In the present study, we investigated four Sargassum species viz., S. crassifolium, S. siliquosum, S. hemiphyllum, and S. hemiphyllum var. chinense for various bioactivities. From the four species, we made eight fucoidan extracts, namely SC, SCH, SS, SSH, SH, SHH, SHC, and SHCH with or without a compressional puffing pretreatment. The compressionalpuffing process increased the extraction yield of fucoidan and decreased levels of impurities (proteins and polyphenols). Among the eight fucoidans, SS (IC50 DPPH 0.46±0.01 mg/mL; IC50 ABTS•+ 0.09±0.00 mg/mL; FRAP value 67.4±0.9 μmol/g extract, vitamin C equivalent) and SHC (IC50 DPPH 0.53±0.17 mg/mL; IC50 ABTS•+ 0.11±0.00 mg/mL; FRAP value 55.1±0.6 μmol/g extract, vitamin C equivalent) displayed the highest antioxidant activity; SS (36.4±10.1% at 5 mg/mL for α-amylase; 96.3±0.2% at 1 mg/mL for α-glucosidase) and SHC (35.0±2.2% at 5 mg/mL for α-amylase; 96.5±0.2% at 1 mg/mL for α-glucosidase) showed the strongest α-amylase and α-glucosidase inhibitory activities; SH, SHH and SHC had the most potent anti-inflammatory activity; and SHH had a greatest protective effect against damage to pancreatic cells. Hence, SS, SH, SHH, and SHC may be effective health-promoting agents for nutraceutical products. [ABSTRACT FROM AUTHOR]