Supawan Thawornchinsombut

Peptides-Derived from Thai Rice Bran Improves Endothelial Function in 2K-1C Renovascular Hypertensive Rats

In recent years, a number of studies have investigated complementary medical approaches to the treatment of hypertension using dietary supplements. Rice bran protein hydrolysates extracted from rice is a rich source of bioactive peptides. The present study aimed to investigate the vasorelaxation and antihypertensive effects of peptides-derived from rice bran protein hydrolysates (RBP) in a rat model of two kidney-one clip (2K-1C) renovascular hypertension. 2K-1C hypertension was induced in male Sprague-Dawley rats by placing a silver clip around the left renal artery, whereas sham-operated rats were served as controls. 2K-1C and sham-operated rats were intragastrically administered with RBP (50 mg·kg−1 or 100 mg·kg−1) or distilled water continuously for six weeks. We observed that RBP augmented endothelium-dependent vasorelaxation in all animals. Administration of RBP to 2K-1C rats significantly reduced blood pressure and decreased peripheral vascular resistance compared to the sham operated controls (p < 0.05). Restoration of normal endothelial function and blood pressure was associated with reduced plasma angiotensin converting enzyme (ACE), decreased superoxide formation, reduced plasma malondialdehyde and increased plasma nitrate/nitrite (p < 0.05). Up-regulation of eNOS protein and down-regulation of p47phox protein were found in 2K-1C hypertensive rats-treated with RBP. Our results suggest that RBP possesses antihypertensive properties which are mainly due to the inhibition of ACE, and its vasodilatory and antioxidant activity.

Rice Bran Protein Hydrolysates Improve Insulin Resistance and Decrease Pro-inflammatory Cytokine Gene Expression in Rats Fed a High Carbohydrate-High Fat Diet

A high carbohydrate-high fat (HCHF) diet causes insulin resistance (IR) and metabolic syndrome (MS). Rice bran has been demonstrated to have anti-dyslipidemic and anti-atherogenic properties in an obese mouse model. In the present study, we investigated the beneficial effects of rice bran protein hydrolysates (RBP) in HCHF-induced MS rats. After 12 weeks on this diet, the HCHF-fed group was divided into four subgroups, which were orally administered RBP 100 or 500 mg/kg, pioglitazone 10 mg/kg, or tap water for a further 6 weeks. Compared with normal diet control group, the MS rats had elevated levels of blood glucose, lipid, insulin, and HOMA-IR. Treatment with RBP significantly alleviated all those changes and restored insulin sensitivity. Additionally, RBP treatment increased adiponectin and suppressed leptin levels. Expression of Ppar-γ mRNA in adipose tissues was significantly increased whereas expression of lipogenic genes Srebf1 and Fasn was significantly decreased. Levels of mRNA of proinflammatory cytokines, Il-6, Tnf-α, Nos-2 and Mcp-1 were significantly decreased. In conclusion, the present findings support the consumption of RBP as a functional food to improve insulin resistance and to prevent the development of metabolic syndrome.

Effects of Bicarbonate, Xanthan Gum, and Preparation Methods on Biochemical, Physicochemical, and Gel Properties of Nile Tilapia (Oreochomis niloticus Linn) Mince

This study was aimed to determine the effects of phosphate compound substitutions (sodium bicarbonate and xanthan gum) and preparation methods—headed, gutted whole fish, and mince; fresh and after frozen storage (−20°C for 3 months)—on Nile tilapia mince qualities. Results showed that bicarbonate (0.3% with 8% sucrose/sorbitol) is an efficient phosphate compound replacement as evidenced by the comparative values of salt extractable protein, Ca2+-ATPase activity, total sulfhydryl content, and textural properties to those of the phosphate-added—0.3% sodium tripolyphosphate (STPP) with 8% sucrose-sorbitol—sample after 3-month frozen storage (p > 0.05). Both cryoprotected samples containing STPP or bicarbonate exhibited higher denaturation temperatures of myosin than others. Xanthan gum (0.5%) could neither stabilize the biochemical and physicochemical properties of mince during 3-month frozen storage nor improve textural properties of gel from frozen whole fish.

Rice bran protein hydrolysates reduce arterial stiffening, vascular remodeling and oxidative stress in rats fed a high-carbohydrate and high-fat diet

PurposeRice bran protein hydrolysates (RBPH) contain highly nutritional proteins and antioxidant compounds which show benefits against metabolic syndrome (MetS). Increased arterial stiffness and the components of MetS have been shown to be associated with an increased risk of cardiovascular disease. This study aimed to investigate whether RBPH could alleviate the metabolic disorders, arterial stiffening, vascular remodeling, and oxidative stress in rats fed a high-carbohydrate and high-fat (HCHF) diet.MethodsMale Sprague–Dawley rats were fed either a standard chow and tap water or a HCHF diet and 15xa0% fructose solution for 16xa0weeks. HCHF rats were treated orally with RBPH (250 or 500xa0mg/kg/day) for the final 6xa0weeks of the experimental period.ResultsRats fed with HCHF diet had hyperglycemia, insulin resistance, dyslipidemia, hypertension, increased aortic pulse wave velocity, aortic wall hypertrophy and vascular remodeling with increased MMP-2 and MMP-9 expression. RBPH supplementation significantly alleviated these alterations (Pxa0<xa00.05). Moreover, RBPH reduced the levels of angiotensin-converting enzyme (ACE) and tumor necrosis factor-alpha in plasma. Oxidative stress was also alleviated after RBPH treatment by decreasing plasma malondialdehyde, reducing superoxide production and suppressing p47phox NADPH oxidase expression in the vascular tissues of HCHF rats. RBPH increased plasma nitrate/nitrite level and up-regulated eNOS expression in the aortas of HCHF-diet-fed rats, indicating that RBPH increased NO production.ConclusionRBPH mitigate the deleterious effects of HCHF through potential mechanisms involving enhanced NO bioavailability, anti-ACE, anti-inflammatory and antioxidant properties. RBPH could be used as dietary supplements to minimize oxidative stress and vascular alterations triggered by MetS.

Rice bran protein hydrolysates attenuate diabetic nephropathy in diabetic animal model

IntroductionDiabetic nephropathy (DN) is an important microvascular complication of uncontrolled diabetes. The features of DN include albuminuria, extracellular matrix alterations, and progressive renal insufficiency. Rice bran protein hydrolysates (RBPs) have been reported to have antihyperglycemic, lipid-lowering, and anti-inflammatory effects in diabetic rats. Our study was to investigate the renoprotective effects of RBP in diabetic animals and mesangial cultured cells.MethodsEight-week-old male db/m and db/db mice were orally treated with tap water or RBP (100 or 500xa0mg/kg/day) for 8xa0weeks. At the end of the experiment, diabetic nephropathy in kidney tissues was investigated for histological, ultrastructural, and clinical chemistry changes, and biomarkers of angiogenesis, fibrosis, inflammation, and antioxidant in kidney were analyzed by Western blotting. Protection against proangiogenic proteins and induction of cytoprotection by RBP in cultured mesangial cells was evaluated.ResultsRBP treatment improved insulin sensitivity, decreased elevated fasting serum glucose levels, and improved serum lipid levels and urinary albumin/creatinine ratios in diabetic mice. RBP ameliorated the decreases in podocyte slit pore numbers, thickening of glomerular basement membranes, and mesangial matrix expansion and suppressed elevation of MCP-1, ICAM-1, HIF-1α, VEGF, TGF-β, p-Smad2/3, and type IV collagen expression. Moreover, RBP restored suppressed antioxidant Nrf2 and HO-1 expression. In cultured mesangial cells, RBP inhibited high glucose-induced angiogenic protein expression and induced the expression of Nrf2 and HO-1.ConclusionRBP attenuates the progression of diabetic nephropathy and restored renal function by suppressing the expression of proangiogenic and profibrotic proteins, inhibiting proinflammatory mediators, and restoring the antioxidant and cytoprotective system.

The production of hydrolysates from industrially defatted rice bran and its surface image changes during extraction: Production of hydrolysates from industrially defatted rice bran

BACKGROUNDnThis research employed a mild subcritical alkaline water (mild-SAW) extraction technique to overcome the difficulty of active compound extractability from industrially defatted rice bran (IDRB). Mild-SAW (pH 9.5, 130 °C, 120 min) treatment followed by enzymatic hydrolysis (Protease G6) was applied to produce rice bran hydrolysate (RBH). Response surface methodology was used to identify proteolysis conditions for maximizing protein content and ABTS radical scavenging activity (ABTS-RSA). Microstructural changes occurring in IDRB during extraction were monitored. The selected RBH was characterized for protein recovery, yield, antioxidant activities, phenolic profile and hydroxymethylfufural (HMF) content.nnnRESULTSnOptimal proteolysis conditions were 20 mL kg-1 IDRB (enzyme/substrate ratio) for 6 h. Under these conditions, the yield, ABTS-RSA, ferric reducing antioxidant power and total phenolic content of the RBH were 46.1%, 294.22 µmol trolox g-1 , 57.72 µmol FeSO4 g-1 and 22.73 mg gallic acid g-1 respectively, with relatively low HMF level (0.21 mg g-1 ). The protein recovery was 4.8 times greater than that by conventional alkaline extraction. Its major phenolic compounds were p-coumaric and ferulic acids. The microstructural changes of IDRB confirmed that the mild-SAW/Protease G6 process enhanced the release of active compounds.nnnCONCLUSIONnThe process of mild-SAW extraction followed by proteolysis promotes the release of active compounds from IDRB.

Controlling Lipid Oxidation and Volatile Compounds in Frozen Fried Fish Cake Prepared with Rice Bran Hydrolysate

ABSTRACT Fried fish cakes formulated with (1) no antioxidant (control), (2) 1% rice bran hydrolysate (RBH), (3) 2% RBH, (4) 0.05% rosemary oil, and (5) 0.02% butylated hydroxyanisole/butylated hydroxytoluene (BHA/BHT) were investigated for their oxidation values following 0–9 freeze-thaw cycles. Both lipid oxidation and protein oxidation were significantly obstructed when RBH or BHA/BHT was used. RBH at 2% was equally effective as 0.02% BHA/BHT. Headspace solid phase microextraction (HS-SPME), which measures volatile compounds that determine lipid oxidation, demonstrated the effectiveness of RBH. The development of rancid volatile compound (i.e., hexanal) levels in fried fish cakes decreased during 0–9 freeze-thaw cycles. This study demonstrates that RBH is as an effective antioxidant comparable to commercial antioxidants (BHA/BHT) in frozen fried fish cakes. Consequently, RBH can be a consumer-friendly and natural antioxidant ingredient.

Optimal Conditions to Remove Chemical Hazards in Fish Protein Isolates from Tilapia Frame Using Response Surface Methodology

Response surface methodology (RSM) was employed to maximize the removal of phospholipids (PLs) and other chemical hazards in tilapia protein isolates made from tilapia frame (TF). CaCl2 and the ratio of water to minced tilapia frame (W:TF) were the significant variables affecting PLs reduction. The optimum condition for maximal PLs reduction (90.0%) was: 10.25 mM CaCl2 and a W:TF of 7.8:1, while other variables were fixed at 5 mM citric acid, 60 min incubation, pH 11, and centrifugal speed of 8,000 × g. At these conditions, the great reduction of lipids (93.9%), Hg (97.6%), and As (95.5%), as well as 86.1% of protein recovery, were obtained. Protein isolates with significantly reduced chemical hazards and lipids were successfully prepared from tilapia frames using the alkaline extraction assisted with CaCl2 and citric acid.

Textural Properties of Gel Made from Hybrid Catfish (Clarias macrocephalus x C.gariepinus) Fillets Chilled in Ice and at Temperature of 4 ÌC

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