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The purpose of this study was to evaluate the antioxidant and hypocholesterolemic activities of sardine and bogue protein hydrolysates in cholesterol-fed rats.

In total, 18 male Wistar rats (220 ± 10 g) fed 20 per cent casein, 1 per cent cholesterol and 0.5 per cent cholic acid were divided into three groups and received a daily gavage of 250 mg of sardine (SPH) or bogue (BPH) protein hydrolysates for 30 days. The third group, named control group (CG), received in the same conditions water. Lipoproteins were fractionated by size-exclusion fast protein liquid chromatography, and serum lipids, apolipoproteins and lipoproteins were assayed.

In SPH and BPH groups, serum total cholesterol concentrations were −66 per cent lower than in CG. This corresponded to the decreased very low-density lipoprotein-C in the former groups. Moreover, BPH treatment reduced low-density lipoprotein-C compared with CG and SPH groups. Compared with CG, serum phospholipids were reduced by SPH and BPH. Furthermore, BPH increased significantly APOA4 and sphingomyelin but lowered phosphatidylcholine. In the latter group, serum lecithin cholesterol acyltransferase activity was +23 per cent higher, but with SPH, this activity was −35 per cent reduced compared with CG. Apolipoprotein A-I contents were similar in the three groups. Compared with CG, hydroperoxide and lipid peroxidation contents in serum and lipoprotein fractions were reduced by SPH and BPH. Compared with CG, serum superoxide dismutase and glutathione peroxidase activities were increased in the treated groups, particularly in the BPH group.

These results suggest that sardine protein hydrolysates and particularly those of bogue could be a very useful natural compound to prevent hypercholesterolemia by both improving the lipid profile and modulating oxidative stress in cholesterol-fed rats.

The purpose of this paper was to evaluate the effect of sardine protein on the redox status in rats fed a cholesterol‐rich diet.

Hypercholesterolemic rats were divided into two groups fed diets enriched with cholesterol and containing 20 percent of sardine proteins (SPc) or casein (CASc) for 28 days. A control group was fed a standard diet (CAS).

After 28 days of experiment, no significant difference in serum total cholesterol triacylglycerols and uric acid was found with the three diets. Serum albumin content was, respectively, 2‐fold higher in SPc than those in CASc group. Compared to CAS, this value was 1.3‐fold lower in CASc group. In liver and heart, lipid peroxidation was 1.7‐ and 2‐fold lower in SPc compared with CASc and CAS, respectively. In red blood cells and epididymal fat, superoxide dismutase activity was, respectively, 1.3‐and 3‐fold higher in SPc compared to CASc. Epididymal fat and heart catalase activity were, respectively, elevated (+50 and +79 percent) in SPc than in CASc. Sardine protein decreased nitric oxide levels in heart and epididymal fat (twofold) compared to CASc but compared to control group, nitric oxide value was higher in epididymal fat (2‐fold) and liver (3‐fold).

Sardine protein exerts a beneficial action against oxidative stress caused by dietary cholesterol specifically in the heart by reducing lipid peroxidation and enhancing catalase activity.

The purpose of this study was to isolate Whitemouth croaker protein by alkaline solubilization process and evaluate their nutritional quality to evaluate the bioavailability of essential amino acids.

The proximate composition, essential amino acid composition, in vitro digestibility, apparent bioavailability, chemical score of amino acids and SDS-PAGE were determined for the isolated croaker proteins.

The isolated protein showed a high level of protein 92.21 percent and low amount of lipids 0.57 percent. The protein is rich in lysine and leucine, 108.73 and 96.75 mg/g protein, respectively. The protein isolate had high digestibility, 94.32 percent, which indicates proper utilization of this protein source, while the tryptophan had lower bioavailability (12.58 mg amino acid/mg protein). The high chemical scores were found for the amino acids lysine, methionine+cysteine (6.79 and 5.14). SDS-PAGE of proteins extracted showed appearance of the heavy chain of myosin (220 kDa), actin (50 kDa) and other fractions, with molecular weight between 20 and 50 kDa, such as troponin I, C and T.

The products obtained from croaker muscle can be incorporated as a high value supplements in human diets. The isolated protein exhibited a high content of essential amino acids and digestibility, indicating that the protein has a high nutritional quality.

This paper aims to study the effect of green lemon zest combined with sardine proteins in diabetic hypertensive rats (DHRs).

Male Wistar rats (n = 30) weighing 250 ± 10 g were divided into five groups. The first group consumed a diet containing 20 per cent casein (C). The other four groups are rendered diabetic by intraperitoneal injection of streptozotocin (40 mg/kg body weight), then hypertensive by subcutaneous implantation controlled time-release pellet containing ouabain (0.25 mg/pellet). One untreated group (DHR) consumed 20 per cent casein and the three other groups consumed the same diet supplemented with 2 per cent green lemon zest (DHR-lz), or with 20 per cent of sardine protein (group DHR-sp) or with the combination of both sardine proteins and green lemon zest (group DHR-sp + lz).

DHRs feeding on the combination of both sardine protein (sp) and lemon zest (lz) induced a significant decrease of diastolic blood pressure and heart rates values compared with DHR (p < 0.05). The HDLC values were increased by +55 per cent in DHR-sp + lz compared with DHR group. Moreover, plasma non-HDLC concentrations were decreased significantly compared to DHR, DHR-lz, DHR-sp and C groups. In DHR-sp + lzvs DHR group, TBARS values were decreased by −25 per cent in the liver. Moreover, kidney TBARS were significantly reduced by −66, −51, −65 and −67 per cent compared with C, DHR, DHR-lz and DHR-sp, respectively.

These results suggest that consumption of green lemon zest combined with sardine proteins can reduce blood pressure and tissue oxidative damage and, therefore, help to prevent cardiovascular complications in hypertensive diabetic patients.

This study was aimed to estimate and compare the contents of protein and amino acids in raw, boiled and fried fishes of Indian mackerel “kembong” (Rastrelliger kanagurta), sardine (Sardina pilchardus), red tilapia (Oreochromis mossambicusx) and black tilapia (Oreochromis mossambicus). Protein contents of raw mackerel, sardine, red and black tilapia were 8.1±0.0, 8.4±0.1, 9.6±0.4 and 9.0±0.0 percent, respectively. In a boiled fish, the protein contents were 7.9±0.1, 7.7±0.0, 7.5±0.1 and 8.9±0.1 percent, respectively, and for a fried fish the values were 8.6±0.5, 8.9±0.1, 9.1±0.2 and 8.4±0.0 percent, respectively. It was found that there was a significant difference (p<0.01) in the protein content of the raw fish compared to the heat‐treated ones for all the fishes. The study detected 17 components of essential amino acids (lysine, histidine, threonine, valine, methionine, leucine, isoleucine and phenylalanine) and non‐essential amino acids (arginine, aspartic acid, serine, glutamic acid, proline, glycine, alanine, cystein and tyrosine) in all the fishes. There was no significant difference in amino acids content among the boiled and fried fishes. In conclusion, heat treatment for five minutes in boiling water (100°C) and frying for three minutes in palm oil (160°C) did not alter the quality of protein in all the fishes studied.

The purpose of this study was to investigate the impact of replacing two different fats on dyslipidemia, glycemic balance and adipose tissue redox status in obese rats.

Obesity was induced by feeding a high-mutton-fat diet during three months. An experimental group (n = 24) was divided into two groups that were fed during one month, 20 per cent of margarine or sardine oil. At Day 30, six rats from each group were sacrificed and the remaining rats were then subjected to a change in diet for one month: margarine was replaced by sardine oil and inversely, and then the rats were sacrificed. Three other groups (n = 6), each fed during two months, 20 per cent of margarine, sardine oil or mutton fat, served as controls.

Substitution of sardine oil by margarine compared to control sardine oil had increased triacylglycerols (TGs), glycosylated hemoglobin (HbA1c) and isoprostanes (IsoPs) values, but decreased thiobarbituric acid reactive substances (TBARS) and superoxide dismutase activity. Replacing margarine by sardine oil compared to control margarine reduced total cholesterol, TG, HbA1c, TBARS and IsoP contents but enhanced glutathione reductase and peroxidase activities. Nevertheless, comparing with the mutton fat, the two substitutions had improved glycemic and lipidic abnormalities and attenuated lipoperoxidation by enhancing enzymatic antioxidant defense. These favorable effects were better when margarine was replaced by sardine oil.

Substituting margarine with sardine oil seems to attenuate beneficial cardiometabolic risk markers associated to obesity and potentiate efficiency adipose tissue against the oxidative stress induced by the obesogenic diet.

The purpose of this study was to determine the effects of chickpea (Cicer arietinum) protein hydrolysates prepared at two degrees of hydrolysis (DH) on lipoprotein profile and on oxidant status in cholesterol-fed rats.

Eighteen male Wistar rats (220 ± 10 g) were divided into three groups and fed for 30 days a diet containing 20 per cent casein supplemented with 1 per cent cholesterol and 0.5 per cent cholic acid. During the experimentation, the first and the second groups received daily by gavage 250 mg of chickpea protein hydrolysates/rat at DH = 8 per cent (CPH8) and DH = 17 per cent (CPH17), respectively. The third group, named control group (CG), received water under the same conditions.

Serum total cholesterol concentrations were reduced in CPH8 (p < 0.0073) and CPH17 (p < 0.0004) groups versus CG. This reduction corresponded to a lower very-low-density lipoprotein (VLDL)-cholesterol (p < 0,0019). CPH17 reduced low-density lipoprotein- and high-density lipoprotein (HDL)-cholesterol (p < 0.0001) but increased apolipoprotein A4 (p < 0.002) concentrations and lecithin-cholesterol acyltransferase activity (p < 0.0001). APOA1 remained unchanged in the treated groups. Liver total and esterified cholesterol contents were twofold lower in both treated groups versus CG. CPH8 increased triacylglycerols and phospholipids (p < 0.0001) contents, while CPH17 decreased those of unesterified cholesterol (p < 0.0016). Compared with CG, CPH8 and CPH17 reduced serum (p < 0.0001) and lipoprotein hydroperoxides by stimulating paraoxonase activity (p < 0.0001). However, only CPH17 treatment reduced serum, VLDL- and HDL-malondialdehyde contents and improved glutathione peroxidase activity (p < 0.061).

Thus, chickpea protein hydrolysates and especially hydrolysed at DH = 17 per cent may have a great potential for use as a nutraceutical to reduce hypercholesterolaemia and, by consequence, oxidative stress. Therefore, the degree of enzymatic hydrolysis has a significant influence on the production of potent bioactive peptides.

This paper aims to study the effect of cooking and food additives, such as lemon juice and vinegar, on phenols and flavonoids contents and antioxidant activity of purslane.

The Folin–Ciocalteu method was used to determine total phenols content (TP), while total flavonoid content (TF) was determined by the aluminum chloride method. Two methods were used for determination of antioxidant activity: DPPH (1, 1-diphenyl-2-picrylhydrazyl) assay to determine radical scavenging activity, and ferric-reducing antioxidant power (FRAP) to measure the reducing power.

According to the results, leafs had higher values of TP, TF and antioxidant activity than aerial parts. Both lemon juice and vinegar retracted antioxidant properties of leafs. TP and TF of leaves showed deterioration after treatment with lemon by 58% and 21.8%, respectively, and FRAP and radical scavenging activity decreased by 75.8% and 74.5%, respectively (p < 0.001). Also, TP, TF, FRAP and DPPH radical scavenging activity decreased in leaves by 82.2%, 30.5%, 87.8% and 90.9%, respectively, after treatment of leaves with vinegar. TF increased after cooking in studied parts, where no significant statistical difference was observed in TP and antioxidant activity (DPPH assay and FRAP) of cooked aerial parts. Adding lemon juice after cooking increased antioxidant properties of purslane (p < 0.001).

Purslane has antioxidant activity because it is rich in polyphenols and flavonoids. Effects of food additives and cooking were studied using different measurements. According to the authors’ knowledge, this is the first work that studied the effect of food additives on antioxidant properties of purslane.

The purpose of this study was to determine the effects of whole oat, oat bran and refined oat incorporation in a high-fat diet (HFD) on cardio-metabolic risk biomarkers in rats with type 2 diabetes mellitus (T2DM).

T2DM was induced by feeding male rats with an HFD for 10 weeks, followed by a low dose of streptozotocin. T2DM rats were then divided into four homogeneous groups. Three groups consumed an HFD containing 45 per cent (g/100 g diet) whole oat, oat bran or refined oat. The fourth untreated group (control) received the HFD.

The results showed that whole oat and oat bran, compared with refined oat and control, effectively reduced food intake (p < 0.007), arterial blood pressure (p = 0.0001), glycemia (p < 0.001), insulinemia (p < 0.01), glycosylated haemoglobin (p < 0.001) as well as homeostasis insulin resistance (HOMA-IR) (p < 0.001). They also improved blood lipid levels and reverse cholesterol transport by reducing serum total cholesterol (p = 0.0001), triacylglycerols (p < 0.05), very-low- (p = 0.0001) and low-density lipoproteins cholesterol contents (p < 0.02) increasing lipids (p < 0.002) and cholesterol excretion (p = 0.0001), and high-density lipoprotein cholesteryl esters (HDL₂-CE) concentrations (p = 0.0001) and stimulating lecithin: cholesterol acyltransferase (LCAT) activity (p = 0.0001). Moreover, they attenuated lipid peroxidation by increasing paraoxonase-1 (PON-1) atheroprotective activity (p < 0.05).

In T2DM rats, whole oat and particularly, its bran incorporated into an HFD improves arterial blood pressure, glycemic balance and lipid metabolic pathway by reducing hypertriglyceridemia and hypercholesterolemia and increasing atheroprotective activities of LCAT and PON-1. In contrast, refined oat accentuates the risk factors associated with diabetes.

This study aims to assess the quality and microbial safety of traditional smoked spotted tilapia fish from Lagos State and, by doing so, determine the quality and microbial safety level of traditional smoked spotted tilapia fish, their distribution, effects and possible public health implications of the quality/rancidity indices and microorganisms on the consumers.

Fresh spotted tilapia fish (100 samples) were collected from 20 different fishing/processing centres and divided into two batches. One batch was smoked with local drum kiln at processing centres, and the second batch was smoked with convective smoking kiln as control in the laboratory. Each batch was assessed for moisture content, protein content, fat content, crude fibre content, ash content, pH, thiobarbituric acid (TBA), total volatile base- nitrogen (TVB-N), trimethylamine (TMA), peroxide value (PV) and free fatty acid (FFA) values. Microbiological analyses were also conducted. Each batch was assessed for total viable count (TVC), fungal count, Listeria monocytogenes count, Staphylococcus aureus count, Salmonella paratyphi count and presence or absence of Escherichia coli.

The results of the proximate composition, quality indices and microbiological analyses revealed that there was significant variations (p < 0.05) between smoked fish with different smoking methods. The mean pH, TBA, TVB-N, TMA, PV and FFA values of fresh and smoked spotted tilapia fish samples were within the range recommended by United States Food and Drug Administration. The mean TVC of fresh spotted tilapia fish samples was 6.3 × 106-8.8 × 108 cfu/g and TVC of samples of smoked spotted tilapia fish and the control were 2.0 × 104-6.4 × 104 cfu/g and 1.0 × 103-8.6 × 103 cfu/g, respectively. The mean L. monocytogenes count of fresh spotted tilapia fish samples was 1.3 × 102-2.4 × 102 cfu/g and that of samples of smoked spotted tilapia fish ranged from 1.6 × 101 to 23.1 × 101 cfu/g while samples of smoked spotted tilapia fish using convective smoking kiln showed no count for L. monocytogenes. The mean S. aureus count of fresh spotted tilapia fish samples ranged from 4.7 × 103 to 8.0 × 103 cfu/g and that of samples of smoked spotted tilapia fish ranged from 5.1 × 102 to 88.6 × 102 cfu/g and 1.1 × 102 to 3.8 × 102 cfu/g. The mean fat content (FC) count of samples of smoked spotted tilapia fish ranged from 1.1 × 101 to 6.0 × 101 cfu/g. S. paratyphi and E. coli were not detected in all smoked spotted tilapia fish samples. The study, however, concluded that the traditional drum smoked spotted tilapia fish could expose consumers to high microbial risk because of the presence of L. monocytogenes.

The fresh fish used in this study were obtained from coastal villages in Lagos State, and there were limitations in getting the samples in time to the processing centres and in preserving the fresh fish because of poor or non-availability of power (electricity).

The paper includes implications for the development of a cost-effective smoked fish, to ensure food safety, enhanced health and improve the preservation and post-harvest losses of fresh fish.

The paper helps in developing an effective smoked method that will produce good-quality smoked fish, reduce the incidence of food poison and enhance the health of consumers.

This research is of value to the traditional fish smokers and consumers. Smoked fish has been implicated as a source of microbial infection in Nigeria and West African sub-region in recent times and the need for good manufacturing practices cannot be overemphasized.