Ines Jemil

The Influence of the Extent of Enzymatic Hydrolysis on Antioxidative Properties and ACE-Inhibitory Activities of Protein Hydrolysates from Goby (Zosterisessor ophiocephalus) Muscle

Antioxidant properties and angiotensin-converting enzyme (ACE) inhibitory activities of protein hydrolysates from goby (Zosterisessor ophiocephalus) muscle, with different degrees of hydrolysis (DH) from 5 to 25xa0%, prepared by treatment with crude proteases extract from smooth hound intestines, were investigated. Goby protein hydrolysates (GPHs) are rich in Gly and Thr, which accounted for 14.1–15xa0% and 11.6–13.2xa0% of the total amino acids, respectively. The antioxidant activities of GPHs were investigated by using several in vitro assay systems. All GPHs exhibited significant metal chelating activity and DPPH free radical-scavenging activity, and inhibited linoleic acid peroxidation. For the ACE-inhibitory activity, as the DH increased, the activity of GPHs increased. The obtained results revealed that antioxidant and ACE-inhibitory activities of GPHs were influenced by the degree of hydrolysis. A medium degree of enzymatic hydrolysis was appropriate to obtain GPHs with good antioxidant activity, while small peptides were essential to obtain high ACE inhibitory activity.

Ameliorating effects of goby fish protein hydrolysates on high-fat-high-fructose diet-induced hyperglycemia, oxidative stress and deterioration of kidney function in rats.

This study investigated the therapeutic potential of undigested goby fish (Zosterisessor ophiocephalus) muscle proteins (UGP) and their hydrolysates on high-fat-high-fructose diet (HFFD)-fed rats. HFFD induced hyperglycemia, manifested by a significant increase in the levels of glucose and glycogen as well as α-amylase activity when compared to normal rats. The administration of GPHs to HFFD-fed rats significantly decreased α-amylase activity and the contents of blood glucose and hepatic glycogen. By contrast, the UGP increased the glucose metabolic disorders in HFFD-fed rats. Furthermore, HFFD-fed rats showed oxidative stress, as evidenced by decreased antioxidant enzyme activities and glutathione (GSH) levels and increased concentration of the lipid peroxidation product malondialdehyde in liver and kidney. Interestingly, the daily gavage of UGP and GPHs improved the redox status in liver and kidney of HFFD-rats by ameliorating or reversing the above-mentioned changes. Moreover, GPHs exhibited a renal protective role by reversing the HFFD-induced decease of uric acid and increase of creatinine levels in serum and preventing some HFFD-induced changes in kidney architecture. The results demonstrate that GPHs contain bioactive peptides that possess significant hypoglycemic and antioxidant properties, and ameliorate renal damage in rats fed hypercaloric diet.

A peptidomic approach for the identification of antioxidant and ACE-inhibitory peptides in sardinelle protein hydrolysates fermented by Bacillus subtilis A26 and Bacillus amyloliquefaciens An6

Antioxidant and angiotensin I-converting enzyme (ACE)-inhibitory activities of sardinelle (Sardinella aurita) protein hydrolysates (SPHs) obtained by fermentation with Bacillus subtilis A26 (SPH-A26) and Bacillus amyloliquefaciens An6 (SPH-An6) were investigated. Both hydrolysates showed dose-dependent antioxidant activities evaluated using various in vitro antioxidant assays. Further, they were found to exhibit ACE-inhibitory activity. Peptides from SPH-A26 and SPH-An6 were analyzed by nESI-LC-MS/MS and approximately 800 peptides were identified. Identified peptides derived mainly from myosin (43% and 31% in SPH-An6 and SPH-A26, respectively). Several peptides identified in both hydrolysates were found to share sequences with previously identified antioxidant and ACE-inhibitory peptides based on Biopep database. Some of these peptides were selected for synthesis and their biological activities were evaluated. Among the synthesized peptides, NVPVYEGY and ITALAPSTM were found to be the most effective ACE-inhibitors with IC50 values of 0.21 and 0.23mM, respectively. On the other hand, NVPVYEGY, which exhibited the highest ACE-inhibitory activity, showed the highest reducing power and peroxyl radical scavenging activities, followed by SLEAQAEKY and GTEDELDKY. The results of this study suggest that fermented sardinelle protein hydrolysates are a good source of natural antioxidant peptides and could have the potential to act as hypotensive nutraceutical ingredients.

Hypolipidemic, antiobesity and cardioprotective effects of sardinelle meat flour and its hydrolysates in high-fat and fructose diet fed Wistar rats

Aims: The present study aims to evaluate the antiobesity, hypolipidemic and cardioprotective effects of fermented sardinelle (Sardinella aurita) protein hydrolysates (FSPHs) produced with two proteolytic bacteria, Bacillus subtilis A26 (FSPH‐A26) and Bacillus amyloliquefaciens An6 (FSPH‐An6). Main methods: Wistar rats were fed during 10 weeks a standard laboratory diet, a high caloric diet (HCD) and a HCD coupled with the oral administration of sardinelle meat flour (SMF) or FSPHs. Key findings: HCD caused hyperlipidemia and increased body weight (BW). The daily oral administration of FSPHs or SMF reduced the total cholesterol (TC), triglycerides (TG) and low‐density lipoprotein cholesterol (LDL‐c) serum levels, and increased the level of high‐density lipoprotein cholesterol (HDL‐c). Nevertheless, FSPHs were found to be more efficient than SMF. FSPHs also lowered hepatic TC and TG content and decreased the pancreatic lipase activity. Further, the administration of FSPHs or SMF decreased the BW gain, the food intake and the relative epididymal adipose tissue weight. FSPHs exhibited a potent cardioprotective effect against heart attack, which was demonstrated by returning atherogenic indexes to their normal levels and the conservation of standard histological structure of the heart and aorta. Significance: The overall results indicate that FSPHs contained bioactive peptides which significantly attenuated hyperlipidemia, and might reduce the risk of cardiovascular disease (CVD) in rats fed HCD. HighlightsFermented sardinelle protein hydrolysates (FSPHs) were prepared by two proteolytic bacteria.Hypercaloric diet (HCD) induced obesity and hyperlipidemia.FSPHs were found to attenuate obesity and hyperlipidemia in HCD‐fed rats.FSPHs exhibited a potent cardioprotective effect.FSPHs could be used as ingredients to formulate functional foods.

Effect of ultrasound pretreatment and Maillard reaction on structure and antioxidant properties of ultrafiltrated smooth-hound viscera proteins-sucrose conjugates

The effect of ultrasound (US) pre-treatment on the evolution of Maillard reaction (MR), induced between low molecular weight (LMW) peptides and sucrose, was studied. LMW peptides (<1kDa) were obtained by the ultrafiltration of smooth hound viscera protein hydrolysates, produced by Neutrase, Esperase and Purafect. MR was induced by heating the LMW peptides in the presence of sucrose for 2h at 90°C, without or with US pre-treatment. During the reaction, a marked decrease in pH values, coupled to the increase in colour of the Maillard reaction products (MRPs), were recorded. In addition, after sonication, the glycation degree was significantly enhanced in Esperase-derived peptides/sucrose conjugates (p<0.05). Moreover, results showed that thermal heating, particularly after US treatment, reduced the bitter taste and enhanced the antioxidant capacities of the resulting conjugates. Hence, it could be concluded that US leads to efficient mixing of sugar-protein solution and efficient heat/mass transfer, contributing to increase the MR rate.

Novel bioactive peptides from enzymatic hydrolysate of Sardinelle (Sardinella aurita) muscle proteins hydrolysed by Bacillus subtilis A26 proteases

Sardinelle protein hydrolysate (SPH), prepared by treatment with Bacillus subtilis A26 proteases, was found to exhibit antibacterial, antioxidant and ACE-inhibitory activities. SPH, with a degree of hydrolysis of 4%, was fractionated by size exclusion chromatography on a Sephadex G-25 into five major fractions (F1-F5). F2, which exhibited the highest antibacterial and ACE-inhibitory activities, and F4, which exhibited the highest antibacterial and antioxidant activities, were further fractionated by reverse phase-high performance liquid chromatography (RP-HPLC) and then analysed using nano-ESI-LC-MS/MS to identify the sequences of peptides. Eight peptides were identified in the sub-fraction F2-A, nine peptides in the sub-fraction F4-B, and 45 peptides in F4-C. Identified peptides were found to share sequences with previously described bioactive peptides based on Biopep database. The results of this study suggest that SPH is a good source of natural bioactive peptides. Hence, it can be used as a potential ingredient in nutraceutical field.

Preventive effect of goby fish protein hydrolysates on hyperlipidemia and cardiovascular disease in Wistar rats fed a high-fat/fructose diet

This study was carried out to investigate the hypolipidemic, cardioprotective and anticoagulant properties of fish goby protein hydrolysates (GPHs) in rats fed a high fat and fructose diet (HFFD). Wistar rats were fed with HFFD for 2 months, coupled with the oral administration of GPHs and undigested goby protein (UGP). Compared with the standard diet, HFFD induced dyslipidemia and liver structure alterations, and increased pancreatic lipase activity. In addition, HFFD caused a significant increase in body weight. Interestingly, administration of UGP and GPHs to HFFD fed rats was efficacious in lowering serum total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-c) as well as hepatic TC and TG, and increased the serum high density lipoprotein cholesterol (HDL-c) content. Moreover, all treatments significantly decreased the atherogenic index and coagulant factor levels (thrombin and prothrombin). UGP and GPH administration also significantly decreased pancreatic lipase activity, which mitigates lipid accumulation. Similarly, UGP and its hydrolysates showed cardioprotective potential revealed by decreasing the risk of atherogenic and coronary artery disease and improving the liver architecture. The ex vivo plasma clotting test showed that GPHs exert a great therapeutic anticoagulant potential. The overall results demonstrated that GPH supplementation can counteract high-fat/fructose diet-induced obesity.

Beneficial effects of fermented sardinelle protein hydrolysates on hypercaloric diet induced hyperglycemia, oxidative stress and deterioration of kidney function in wistar rats

This study investigated the potential effects of fermented sardinelle protein hydrolysates (FSPHs) obtained by two proteolytic bacteria, Bacillus subtilis A26 (FSPH-A26) and Bacillus amyloliquefaciens An6 (FSPH-An6), on hypercaloric diet (HCD) induced hyperglycemia and oxidative stress in rats. Effects of FSPHs on blood glucose level, glucose tolerance, α-amylase activity and hepatic glycogen content were investigated, as well as their effect on the oxidative stress state. Biochemical findings revealed that, while undigested sardinelle proteins did not exhibit hypoglycemic activity, oral administration of FSPHs to HCD-fed rats reduced significantly α-amylase activity as well as glycemia and hepatic glycogen levels. Further, the treatment with FSPHs improved the redox status by decreasing the levels of lipid peroxidation products and increasing the activities of the antioxidant enzymes (superoxide dismutase, glutathione peroxidase and catalase) and the level of glutathione in the liver and kidneys, as compared to those of HCD-fed rats. FSPHs were also found to exert significant protective effects on liver and kidney functions, evidenced by a marked decrease in alkaline phosphatase activity and a modulation of creatinine and uric acid contents. These results indicated the beneficial effect of FSPHs on the prevention from hyperglycemia and oxidative stress.