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Naked oat globulin was hydrolyzed by alcalase, flavourzyme, pepsin, and trypsin in sequence. The hydrolysates (NOGH) were purified using gel chromatography, reversed-phase high performance liquid chromatography (RP-HPLC). Finally, fraction D7d with the highest ACE-inhibitory was subjected to liquid chromatography-mass spectrometry analysis and 14 peptides were identified. Of which, peptide SSYYPFK (890.4 Da) was chose to synthesize based on in silico analysis. The SSYYPFK demonstrated high ACE-inhibitory activity (IC50 : 91.82 µM) with competitive inhibition mode, and could effectively (P < 0.05) lower the systolic blood pressure and diastolic pressure of spontaneously hypertensive rats at the concentration of 100 to 150 mg/kg body weight. Molecular docking simulation demonstrated that SSYYPFK could bind with the active site S1 of ACE via short hydrogen bonds. It could remain the ACE-inhibitory activity after simulated gastrointestinal hydrolysis. Moreover, SSYYPFK showed acceptable renin and endothelin-1 suppressing capacity (47.59% and 27.88% at 1.5 mg/mL, respectively). These results indicated that SSYYPFK may have similar antihypertensive mechanism with captopril, and could be develop to natural antihypertensive products. PRACTICAL APPLICATION: One novel ACE-inhibitory peptide SSYYPFK (890.4 Da) was identified from naked oat globulin hydrolysates. It exhibited relatively high renin and intracellular endothelin-1 suppressing capacity, and could effectively (P < 0.05) lower the systolic blood pressure and diastolic pressure of spontaneously hypertensive rats. This peptide could be used as natural and safe nutraceuticals and/or functional ingredients.

Previous studies have shown that rambutan peel phenolic (RPP) extract has excellent biological activities due to its abundant phenolic content and profile. In this study, the potential anti-osteoporosis (OP) effects of RPP were evaluated by suppressing receptor activator nuclear factor-kappa B ligand (RANKL)-induced differentiation of RAW264.7 cells into osteoclasts and amelioratingretinoic acid-induced OP in rats. Our results showed that RPP efficiently decreased the formation of tartrate-resistant acid phosphatase (TRAP)-positive cells and reduced total TRAP activity in RAW264.7 cells under RANKL stimulation. RPP treatment significantlyameliorated retinoid acid-induced calcium loss in rats (p &lt, 0.05). The serum phosphorus level of osteoporotic rats was increased by RPP treatment, and the serum levels of total alkaline phosphatase and osteocalcin in osteoporotic rats were further reduced. RPP treatment improved the qualities of the femur and tibia, such asbone mineral density, bone length, bone maximum load, cortical bone area ratio, and trabecularelative bone density in osteoporotic rats to some extent. Furthermore, histological analysis showed that RPP effectively improved the bone microstructure of osteoporotic rats by regulating the cortical bone thickness and trabecular bone separation. These results indicate that RPP could have potential applications as a newnutraceutical and functional food in the prevention of OP.

Rambutan peel phenolic (RPP) extracts were prepared via dynamic separation with macroporous resin. The total phenolic content and individual phenolics in RPP were determined. Results showed that the total phenolic content of RPP was 877.11 mg gallic acid equivalents (GAE)/g extract. The content of geranin (122.18 mg/g extract) was the highest among those of the 39 identified phenolic compounds. RPP protected against oxidative stress in H2O2-induced HepG2 cells in a dose-response manner. The inhibitory effects of RPP on cell apoptosis might be related to its inhibitory effects on the generation of intracellular reactive oxygen species and increased effects on superoxide dismutase activity. The in vivo anti-aging activity of RPP was evaluated using an aging mice model that was induced by d-galactose (d-gal). The results showed that RPP enhanced the antioxidative status of experimental mice. Moreover, histological analysis indicated that RPP effectively reduced d-gal-induced liver and kidney tissue damage in a dose-dependent manner. Therefore, RPP can be used as a natural antioxidant and anti-aging agent in the pharmaceutical and food industries.

Albumin is the major fraction of quinoa protein that is characterized as having high nutritional value. However, until now, scant information is available on the bioactivity of quinoa albumin or its hydrolysates. To promote its usage, we extracted albumin in this study from quinoa bran assisted with cellulase and hemicellulose, and hydrolyzed it by alcalase and trypsin to produce bioactive peptides. The hydrolysates (QBAH) were purified by gel filtration and reversed-phase high-performance liquid chromatography (RP-HPLC), followed by identification using liquid chromatography&ndash, mass spectrometry (LC-MS/MS). Furthermore, based on in silico analysis, one angiotensin-I converting enzyme (ACE)-inhibitory and antioxidant peptide, RGQVIYVL (946.6 Da), and two antioxidant peptides, ASPKPSSA (743.8 Da), and QFLLAGR (803.5 Da), from QBAH were synthesized. RGQVIYVL showed a high ACE-inhibitory activity (IC50 = 38.16 &mu, M) with competitive mode of inhibition, and showed significant antihypertensive effect in spontaneously hypertensive rats at a concentration of 100&ndash, 150 mg/kg body weight (bw). Molecular docking simulation showed that it could interact with the active ACE site via hydrogen bonds with high binding power. Moreover, RGQVIYVL, ASPKPSSA, and QFLLAGR all demonstrated high &middot, OH scavenging activity (IC50 = 61.69&ndash, 117.46 &mu, M), ABTS+ scavenging activity (58.29&ndash, 74.28%) and Fe2+ chelating ability (32.54&ndash, 82.48% at 0.5 mg/mL). They could also retain activity after gastrointestinal enzyme digestion. These results indicate that quinoa albumin is a potential source of bioactive peptides possessing antioxidant and ACE-inhibitory activities.

Summary The polysaccharides from the pileus of Dictyophora rubrovolvata (DPP) were extracted by ultrasonic-assisted extraction (UAE) and the operating parameters were optimised by orthogonal experiment. The polysaccharides were separated and purified by DEAE-52 and Sephadex G-100 column chromatography to obtain two fractions of DPP-1s and DPP-2s. The average of molecular weights, monosaccharide compositions, antioxidant and antiglycation activities of DPP-1s and DPP-2s were investigated. The results showed DPP-1s and DPP-2s had high inhibitory effects on oxidation and glycation, and DPP-2s showed stronger bioactivity than DPP-1s, which might be due to their differences in the molecular weight and uronic acid content. Furthermore, the UV and FTIR spectra were used to evaluate the characterisations of DPP-2s, which demonstrated that DPP-2s had no protein and nuclear acid with the pyranose ring structure. This study indicated that DPP-2s could be used as a source of natural antioxidant and antiglycation components.

Acute and subacute studies of rambutan peel phenolic (RPP) extract were conducted by oral administration on Kunming mice and Sprague-Dawley (SD) rats, respectively. Acute toxicity study (14 days) results revealed that the LD50 value of RPP extract was more than 5000 mg/kg bw in vivo. For the subacute study, four different doses were administered to SD rats by daily gavage for 28 days. Subacute toxicity study results indicated that RPP extract did not show any obvious adverse effect at doses of 312 and 625 mg/kg bw. The bw gain was significantly inhibited at 2500 mg/kg bw of RPP extract. RPP extract at doses of 1250 and 2500 mg/kg bw showed toxicities to liver, kidney, and spleen in SD rats according to the results of hematological and biochemical analyses. Furthermore, RPP extract at 2500 mg/kg bw showed toxicity on different tissues according to the results of histopathological analyses.

Rambutan peel phenolics (RPP) have high antioxidant and anti-inflammatory activities. Leu-Ser-Gly-Tyr-Gly-Pro (LSGYGP) possesses good radical scavenging activity and matrix metalloproteinase (MMPs) inhibitory ability. These underlying mechanisms indicated that RPP and LSGYGP may be used for antiphotoaging. Few data on the effects of RPP and LSGYGP on in vivo photoaging are available. We evaluated the effects of RPP and/or LSGYGP on ultraviolet (UV)-induced hairless mice skin photoaging. In particular, we analyzed the additive effect of RPP and LSGYGP. The biochemical indices of mice skin, including composition (collagen and hyaluronic acid [HA] contents), oxidant stress (antioxidant enzyme activities and glutathione and malondialdehyde contents), MMPs (MMP-1, MMP-3, and MMP-9 levels), inflammatory cytokines (interleukin (IL)-1α, tumor nuclear factor-α, and IL-6 levels) and the phosphorylation of the mitogen-activated protein kinase pathway, were determined. Results showed a protective effect of RPP and/or LSGYGP on photoaging skin. LSGYGP showed considerable effects on skin collagen and HA contents. RPP showed improved effects on the regulation of the oxidant stress and inflammatory cytokine levels. RPP and LSGYGP exerted an additive effect on the amelioration of the biochemical indices of UV-induced photoaging skin. The histological changes showed that RPP and LSGYGP recovered the changes in skin tissue and endogenous collagen.

A previous study has shown that tilapia fish skin gelatin hydrolysates inhibited photoaging in vivo, and that, Leu-Ser-Gly-Tyr-Gly-Pro (LSGYGP) identified in the hydrolysate had a high hydroxyl radical scavenging activity. In this study, activities of LSGYGP were further evaluated using ultraviolet B (UVB)-induced mouse embryonic fibroblasts (MEFs). UVB irradiation significantly increased the intercellular reactive oxygen species (ROS) production and matrix metalloproteinases (MMPs) activities and decreased the content of collagen in MEFs. LSGYGP reduced the intercellular ROS generation in UVB-induced MEFs. Meanwhile, the decrease of superoxide dismutase (SOD) activity and the increase of malondiaidehyde (MDA) content were inhibited by LSGYGP. LSGYGP reduced MMP-1 and MMP-9 activities in a dose-dependent manner. Molecular docking simulation indicated that LSGYGP inhibited MMPs activities by docking the active sites of MMP-1 and MMP-9. Furthermore, LSGYGP also affected the intercellular phosphorylation of UVB-induced the mitogen-activated protein kinase pathway. LSGYGP could protect collagen synthesis in MEFs under UVB irradiation by inhibiting oxidative stress and regulating MMPs activities.

Rape bee pollen possesses many nutritional and therapeutic properties because of its abundant nutrimental and bioactive components. In this study, free (FPE) and bound (BPE) phenolic extracts of rape bee pollen were obtained, phenolic and flavonoid contents were determined, and composition of phenolic acids was analyzed. In vitro antioxidant and anti-tyrosinase (TYR) activities of FPE and BPE were compared, and inhibitory melanogenesis of FPE was further evaluated. Results showed FPE and BPE contain total phenolic contents of 11.76 and 0.81 mg gallic acid equivalents/g dry weight (DW) and total flavonoid contents of 19.24 and 3.65 mg rutin equivalents/g DW, respectively. Phenolic profiling showed FPE and BPE fractions contained 12 and 9 phenolic acids, respectively. FPE contained the highest rutin content of 774.87 μg/g. FPE and BPE showed the high antioxidant properties in vitro and high inhibitory activities for mushroom TYR. Higher activities of FPE than those of BPE can be attributed to difference in their phenolic compositions. Inhibitory melanogenesis activities of FPE against B16 were further evaluated. Results showed suppressed intracellular TYR activity, reduced melanin content, and promoted glutathione synthesis (p < 0.05) in FPE-treated cells. FPE reduced mRNA expression of TYR, TYR-related protein (TRP)-1 and TRP-2, and significantly suppressed cyclic adenosine monophosphate (cAMP) levels through down-regulation of melanocortin 1 receptor gene expression (p < 0.05). FPE reduced mRNA expression of microphthalmia-associated transcription factor (MITF), significantly inhibiting intracellular melanin synthesis (p < 0.05). Hence, FPE regulates melanogenesis of B16 cells involved in cAMP/MITF/TYR pathway. These results revealed that FPE can be used as pharmaceutical agents and cosmetics to protect cells from abnormal melanogenesis.

In this study, the effect of tilapia gelatin peptides (TGP) on UV-induced damages to mice skin was evaluated. The antioxidant indicators, lipid, collagen and glycosaminoglycan of mice skin were determined and histological changes of the collagen were depicted. The results showed TGP could alleviate the UV-induced abnormal changes of antioxidant indicators, and the protective effect was in dose-dependent manners. TGP could protect skin lipid and collagen from the UV radiation damages, and the change of glycosaminoglycan was also recovered significantly. The action mechanisms of TGP mainly involved the antioxidant properties and the repairing to endogenous collagen synthesis. Therefore, the key antioxidant peptide was further purified from TGP. Finally, one antioxidant peptide was identified and the amino acid sequence was Leu-Ser-Gly-Tyr-Gly-Pro (592.26 Da). The IC50 value of this peptide on hydroxyl radical scavenging activity was 22.47 μg/mL. TGP could be a novel antiphotoaging agent from natural resources.

In this study, the stable collagen hydrolysate was prepared by alcalase hydrolysis and twice simulated gastrointestinal digestion from Alaska pollock skin. The characteristics of hydrolysates and antioxidant activities in vitro, including 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS•+) scavenging activity, ferric-reducing antioxidant power (FRAP) and hydroxyl radical (OH·) scavenging activity, were determined. After twice simulated gastrointestinal digestion of skin collagen (SGI-2), the degree of hydrolysis (DH) reached 26.17%. The main molecular weight fractions of SGI-2 were 1026.26 and 640.53 Da, accounting for 59.49% and 18.34%, respectively. Amino acid composition analysis showed that SGI-2 had high content of total hydrophobic amino acid (307.98/1000). With the simulated gastrointestinal digestion progressing, the antioxidant activities increased significantly (p < 0.05). SGI-2 was further purified by gel filtration chromatography, ion exchange chromatography and high performance liquid chromatography, and the A1a3c–p fraction with high hydroxyl radical scavenging activity (IC50 = 7.63 μg/mL) was obtained. The molecular weights and amino acid sequences of key peptides of A1a3c–p were analyzed using high resolution mass spectrometry (LC-ESI-LTQ-Orbitrap-MS) combined with de novo software and UniProt of MaxQuant software. Four peptides were identified from A1a3c–p, including YGCC (444.1137 Da) and DSSCSG (554.1642 Da) identified by de novo software and NNAEYYK (900.3978 Da) and PAGNVR (612.3344 Da) identified by UniProt of MaxQuant software. The molecular weights and amino acid sequences of four peptides were in accordance with the features of antioxidant peptides. The results indicated that different peptides were identified by different data analysis software according to spectrometry mass data. Considering the complexity of LC-ESI-LTQ-Orbitrap-MS, it was necessary to use the different methods to identify the key peptides from protein hydrolysates.

To obtain hydrolysates with high degree of hydrolysis (DH) and scavenging radical activity, tilapia skin gelatin (TSG) was hydrolyzed by properase E and multifect neutral. The optimum hydrolysis condition of each enzyme was determined using the orthogonal experiment, and double-enzyme hydrolysis was further applied. The results showed the tilapia skin gelatin hydrolysate (TSGH) obtained by progressive hydrolysis using multifect neutral and properase E had the highest DH and hydroxyl radical scavenging activity. The IC(50) values of TSGH on scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, superoxide anion radical (·O(2)) and hydroxyl radical (·OH) activities were also determined. TSGH was further purified using gel filtration chromatography, ion exchange chromatography, and RP-HPLC. The peptides were identified using nano-LC-ESI mass spectrometry. Finally, two antioxidant peptides were identified and the amino acid sequences were Glu-Gly-Leu (317.33 Da) and Tyr-Gly-Asp-Glu-Tyr (645.21 Da), respectively. The IC(50) values of two peptides on hydroxyl radical scavenging activities were 4.61 μg mL(-1)and 6.45 μg mL(-1), respectively. Therefore, the results demonstrated that the hydrolysates of TSG prepared by multifect neutral and properase E could serve as a source of peptides with high antioxidant activity. It provided a scientific basis for the preparation of antioxidant peptides.

Bioaccessibility of cadmium (Cd) in fresh and cooked Agaricus blazei Murill (AbM) was studied by an in vitro biomimetic digestion system in this paper. The results showed that the Cd content in fresh AbM was 10.27 mg kg(-1) DM. The cooking treatments of boiling and microwaving with water significantly decreased Cd contents in fresh AbM by 36.4% and 30.2% (P

Summary The contents of total dietary fibre (TDF), soluble dietary fibre (SDF), insoluble dietary fibre (IDF) and functional properties of fibre-rich powders (FRP) from pitaya peels with different particle size (FRP80, FRP140 and FRP250) were determined. Results showed that FRP140 had higher TDF (79.37%) and SDF (33.07%) with a balanced ratio of SDF/IDF (1:1.32) and higher water-holding capacity (54.20 g g−1), swelling capacity (50.63 mL g−1), oil-holding capacity (2.65 g g−1) and glucose dialysis retardation index (62.83% at 60 min), compared with FRP80 and FRP250. Therefore, physiochemical properties of FRP140 were further investigated. SDF of FRP140 mainly contained rhamnose (4.95%) and galactose (1.98%), with 9.45% galacturonic acid, while IDF dominantly contained xylose (4.76%) and galactose (3.42%), with 18.54% klason lignin. Total phenolic content was 7.75 mg g−1 and mainly composed of salicylic acid (0.98 mg g−1) and protocatechuic acid (0.45 mg g−1). Furthermore, FRP140 showed significant reducing power, DPPH-scavenging activity and nitrite-scavenging ability.

Antihypertensive effect of long-term oral administration of jellyfish (Rhopilema esculentum) collagen peptides (JCP) on renovascular hypertension rats (RVHs) was evaluated. The systolic blood pressure and diastolic blood pressure of the RVHs were significantly reduced with administration of JCP (p < 0.05), compared with model control group. However, the arterial blood pressure of normal rats showed no significant changes during long-term oral treatment with high dose JCP (p > 0.05). Furthermore, effect of JCP on angiotensin II (Ang II) concentration of plasma had no significance (p > 0.05), but JCP significantly inhibited the Ang II concentration in RVHs’ kidney (p < 0.05). The kidney should be the target site of JCP.

The contents of bioactive compounds (Vitamin C (Vc), carotenoids, total phenolics, phenolic profiles and capsaicinoids) and antioxidant activities (reducing power, DPPH·-scavenging activity and lipid peroxidation inhibition ability) of nine peppers from Yunnan province China, belonging to seven cultivars, were determined. Red and green Point pepper/Long-point pepper were from the same cultivars at different maturity stages. Results showed that all fresh pepper samples were rich in Vc, carotenoids, and total phenolics. Vc contents varied mainly depending on the pepper cultivars, except for the ripened stages. The phenolic content in red Fructus Capsici (Capsium frutescens L.) was significantly higher than that of others (Capsium annuum L.) (p

Gelatin extracted from Pacific cod skin was hydrolysed with serials of protease. Then, the effects of gelatin and polypeptides on melanogenesis and antioxidant were assessed using B16 melanoma cell and reactive oxygen species scavenging ability. Polypeptides showed better scavenging properties on superoxide anions and hydroxyl radical in vitro than gelatin. PEP1 (2–6 kDa) exhibited the highest inhibition of melanogenesis and tyrosinase activity without affecting cell growth. PEP1 (100 µg/mL) significantly reduced the melanin content to 60.5% of control and tyrosinase activity to 51.7% of control, respectively (P

Summary The effects of boiling and microwaving on nutritional compositions, antioxidant components and antioxidant activities of fresh and frozen A. blazei Murril (AbM) were evaluated and compared. The results showed that the contents of crude protein, ash, total soluble protein, total soluble sugar, vitamin C, and total phenolics decreased by both cooking treatments, but no significant changes were observed in lipids. Amino acid composition analysis showed that the ratio of total essential amino acids to total amino acids increased, and the ratio of total non-essential amino acids to total amino acids thus decreased by both cooking treatments. Boiling and microwaving significantly decreased the contents of glucose, galactose and mannose, and the effect of boiling was higher than that of microwaving. Furthermore, boiling and microwaving significantly decreased the DPPH-scavenging activity and reducing power of AbM. Analysis of the relations between the antioxidant activities and total phenolic concentrations testified that the cooking treatments not only decreased the total phenolic contents, but also changed the types and relative amounts of phenolic compounds of AbM.

Whereas the preparation and biological properties of rambutan peel phenolics (RPP) were explored in our previous studies, the metal chelating, inhibitory DNA damage, and anti-inflammatory activities of RPP were evaluated and the important phenolics of RPP quantified in this study. Results showed that RPP had high Fe2+ and Cu2+-chelating activities with EC50 of 0.80 mg/mL and 0.13 mg/mL, respectively. RPP effectively decreased the production of hydroxyl radical with IC50 of 62.4 &mu, g/mL. The protective effects of RPP against AAPH-induced DNA damage were also explored. RPP efficiently inhibited peroxyl radical-induced plasmid DNA strand breakage. The anti-inflammatory effects of RPP were determined using a lipopolysaccharide (LPS)-induced RAW 264.7 cell model. RPP significantly inhibited the production of nitric oxide (NO) and controlled the levels of inducible NO synthase mRNA in LPS-induced RAW 264.7 cells. The inhibitory activity increased in a dose-dependent manner. The above bioactivity of RPP was associated with its phenolic content and phenolic profiles. Furthermore, the contents of geraniin and corilagin in RPP were determined by an ultra-high performance liquid chromatography coupled with triple quadruple mass spectrometry (UPLC-QQQ-MS), showing 140.02 and 7.87 mg/g extract dry weight. Thus, RPP has potential applications as a novel nutraceutical and functional food in health promotion.

When the model systems containing enzyme-hydrolyzed wheat protein, sugars and cysteine were heated with different time-temperature regimes, the Maillard reaction produced meaty aromas. The absorbance and fluorescence of the heated model systems were measured to characterize the Maillard reaction progress and the product profiles. The results showed that two ultraviolet (UV) absorbance peaks and fluorescence developed and both rapidly increased, indicating the accumulation of low molecular weight substances (LMWSs). At higher temperature, the UV-absorbance reached a plateau, while fluorescence reached a maximum and then decreased, suggesting that LMWSs polymerized to high molecular melanoidins. LMWSs are the most important Maillard flavor compounds. The over-polymerization of LMWSs is undesired for Maillard flavor production. The results showed that correlating the time-temperature regime, corresponding to the maximum UV-absorbance and fluorescence and the minimum browning, to the optimum conditions for Maillard flavor production was an easy and efficient way to process design and production quality monitor. Furthermore, 0–139.7 μg acrylamide per kilogram eHWP was formed in the Maillard reaction.

BACKGROUND: Jellyfish collagen was hydrolysed with trypsin and properase E, and jellyfish collagen peptide (JCP) was purified from the enzymatic hydrolysate using ion exchange chromatography and gel filtration. The antioxidant activity of JCP in a linoleic acid emulsion system, its superoxide anion- and hydroxyl radical-scavenging activities and its copper-chelating ability were evaluated in vitro. Initial investigations of JCP's ability to inhibit melanogenesis were carried out using cultured B16 melanoma cells. RESULTS: The molecular weight distribution of JCP was from 400 to 1200 Da. Amino acid analysis showed that JCP was rich in Gly, Pro, Ser, Ala, Glu and Asp and had a total hydrophobic amino acid content of 384.2 g kg−1. JCP showed high antioxidant activity (IC50147.8 µg mL−1), superoxide anion-scavenging activity (IC5021.9 µg mL−1), hydroxyl radical-scavenging activity (IC5016.7 µg mL−1) and copper-chelating ability (IC5088.7 µg mL−1) in vitro. It also significantly inhibited intracellular tyrosinase activity, decreased melanin content and enhanced glutathione synthesis (P < 0.05). Furthermore, JCP decreased intracellular cAMP levels and suppressed tyrosinase mRNA expression. CONCLUSION: Based on the results of this study, JCP exerts anti-melanogenic actions via its antioxidant properties and copper-chelating ability. JCP could be used as a natural skin-lightening agent in the medicine and food industries. Copyright © 2009 Society of Chemical Industry

Collagen (JC) was extracted from jellyfish (Rhopilema esculentum) and hydrolyzed to prepare collagen hydrolysate (JCH). The protective effects of JC and JCH against UV-induced damages to mice skin were evaluated and compared in this article. JC and JCH could alleviate the UV-induced abnormal changes of antioxidative indicators, including the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities and the contents of glutathione (GSH) and malondiaidehyde (MDA). JC and JCH could protect skin lipid and collagen from the UV radiation damages. Furthermore, the changes of total ceramide and glycosaminoglycan in skin were recovered significantly by JC and JCH. The action mechanisms mainly involved the antioxidative properties and the repairing to endogenous collagen synthesis of JC and JCH in vivo. JCH with the lower molecular weight showed much higher effects than JC. The results indicated that JCH was a novel antiphotoaging agent from natural resources.

Gelatin was extracted from Pacific cod (Gadus macrocephalus) skin and hydrolysed sequentially with pepsin and alkaline protease. The hydrolysates were fractionated into two ranges of molecular weight (PEP1: 2000 Da

Fish skin collagen hydrolysates (FSCH) were prepared from walleye pollock (Theragra chalcogramma) using a mixture of enzymes, namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH was mainly composed of low-molecular-weight peptides and the relative proportion of

Recent studies have shown that rambutan peel phenolic (RPP) extract demonstrate high antioxidant and antiglycation activities in vitro and in vivo. This study further evaluated the anti-diabetic activity of RPP in a mouse model of Type II diabetes induced by streptozotocin combined with high-fat diet. Results showed that RPP increased the body weight and reduced the fasting blood glucose level of the diabetic mice. RPP significantly reduced the serum levels of total cholesterol, triglyceride, creatinine, and glycated serum protein in diabetic mice in a dose-dependent manner. Glycogen content in mice liver was recovered by RPP, which further increased the activity of superoxide dismutase and glutathione peroxidase and reduced lipid peroxidation in diabetic mice. Histological analysis showed that RPP effectively protected the tissue structure of the liver, kidney, and pancreas. In addition, RPP decreased the mesangial index and inhibited the expression of TGF-β in the kidney of diabetic mice.

Tilapia frame protein was hydrolyzed by different proteases, including properase E, pepsin, trypsin, flavourzyme, neutrase, gc106 and papain, to obtain antioxidant peptides. The tilapia frame protein hydrolysate (TFPH) obtained by trypsin exhibited the highest degree of hydrolysis and antioxidant activity. Three series of peptides (TFPH1, TFPH 2 and TFPH 3) were obtained by ultrafiltration of TFPH through molecular weight cut-off membranes of 5, 3 and 1 kDa, respectively, and their IC50 values on scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, superoxide anion radical (•O2), hydrogen peroxides (H2O2) and hydroxyl radical (•OH) activities were determined and compared with glutathione (GSH). The results showed that TFPH1 had the highest antioxidant activity. TFPH1 was further purified using ion exchange chromatography, gel filtration chromatography, and reversed phase high performance liquid chromatography (RP-HPLC). Finally, two antioxidant peptides were identified and the amino acid sequences were identified as Asp-Cys-Gly-Tyr (456.12 Da) and Asn-Tyr-Asp-Glu-Tyr (702.26 Da), respectively. The IC50 values of two peptides on hydroxyl radical scavenging activity were 27.6 and 38.4 μg/mL, respectively.

The influences of cooking methods (steaming, pressure-cooking, microwaving, frying and boiling) on total phenolic contents and antioxidant activities of fruit body of Boletus mushrooms (B. aereus, B. badius, B. pinophilus and B. edulis) have been evaluated. The results showed that microwaving was better in retention of total phenolics than other cooking methods, while boiling significantly decreased the contents of total phenolics in samples under study. Effects of different cooking methods on phenolic acids profiles of Boletus mushrooms showed varieties with both the species of mushroom and the cooking method. Effects of cooking treatments on antioxidant activities of Boletus mushrooms were evaluated by in vitro assays of hydroxyl radical (OH·) -scavenging activity, reducing power and 1, 1-diphenyl-2-picrylhydrazyl radicals (DPPH·) -scavenging activity. Results indicated the changes of antioxidant activities of four Boletus mushrooms were different in five cooking methods. This study could provide some information to encourage food industry to recommend particular cooking methods.

The soluble phenolic compounds of rambutan peels (RP) were extracted by microwave-assisted extraction (MAE) and the operating parameters were optimized. The optimal conditions obtained were ethanol concentration of 80.85%, extraction time of 58.39 s, and the ratio of liquid to solid of 24.51:1. The soluble phenolic content by MAE was 213.76 mg GAE/g DW. The free, soluble conjugate, and insoluble-boaund phenolic compounds were prepared by alkaline hydrolysis, and the contents of 3 fractions were 185.12, 27.98 and 9.37 mg GAE/g DW, respectively. The contents of syringic acid and p-coumaric acid were high in the free fraction, showing 16.86 and 19.44 mg/g DW, and the soluble conjugate and insoluble-bound phenolics were mainly composed of gallic acid and caffeic acid. Furthermore, the antioxidant activities of 3 fractions were evaluated in 5 model systems. Results indicated that the free fraction had high antioxidant activities, compared with the soluble conjugate and insoluble-bound fractions.

To optimize the hydrolysis conditions to prepare hydrolysates of jellyfish umbrella collagen with the highest hydroxyl radical scavenging activity, collagen extracted from jellyfish umbrella was hydrolyzed with trypsin, and response surface methodology (RSM) was applied. The optimum conditions obtained from experiments were pH 7.75, temperature (T) 48.77 degrees C, and enzyme-to-substrate ratio ([E]/[S]) 3.50%. The analysis of variance in RSM showed that pH and [E]/[S] were important factors that significantly affected the process (P0.05 and P0.01, respectively). The hydrolysates of jellyfish umbrella collagen were fractionated by high performance liquid chromatography (HPLC), and three fractions (HF-13000 Da, 1000 DaHF-23000 Da, and HF-31000 Da) were collected. The HF-2 fraction had the highest hydroxyl radical scavenging activity with the highest yield compared with the other two fractions. Furthermore, HF-2 also showed the strongest Cu(2+)-chelating ability and the best tyrosinase-inhibitory activity.