Influence of sonication pretreatment on antiradical and anti-ACE activity of protein hydrolysates from fermented pork loins.

The aim of this study was to assess whether ultrasound treatment (sonification time: 5, 15, and 30 min; constants: ∼40 kHz, ∼2.5 W cm2) can be applied prior to hydrolysis to enhance the anti-radical and angiotensin converting enzyme inhibiting (anti-ACE) effect of the hydrolysates from fermented pork loins. Enzymatic hydrolysis was performed using pepsin, followed by pancreatin. The influence of meat matrix on the course of hydrolysis, shaped using a lactic acid bacteria (LAB)-based starter culture, was also analyzed. It was found that proteases caused a systematic increase in the content of peptides, while pancreatin limited the peptide content in the protein hydrolysate from the loins subjected to spontaneous fermentation. Moreover, for these tests, sonication time had a negligible effect on the peptides content of the hydrolysates. On the other hand, for the sample of LAB-fermented products, both sonication time and stage of hydrolysis promoted the biological activity of the hydrolysates. Samples from the LAB-fermented meat had more peptides at the stage of digestion with pepsin and pancreatin, exhibiting much faster antiradical and anti-ACE activity compared to the control sample. The obtained results suggest that the use of LAB promotes the release of antiradical peptides during the two-step enzymatic hydrolysis, the duration of which can be shortened to achieve satisfactory biofunctionalities. Additional application of sonication pretreatment allows controlling the course of the hydrolysis, as the pro-health, biological effect of some protein-derived sequences is associated with the content of peptides.

Sorghum tannin extract impedes in vitro digestibility and fermentability of nutrients in the simulated porcine gastrointestinal tract.

The site and extent of digestion of sorghum nutrients affected by tannins in the intestine are not clarified. Porcine small intestine digestion and large intestine fermentation were simulated in vitro to determine the effects of sorghum tannin extract on the digestion and fermentation characteristics of nutrients in the mimicked porcine gastrointestinal tract. In experiment 1, low-tannin sorghum grain without or with 30 mg/g sorghum tannin extract were digested by porcine pepsin and pancreatin to measure in vitro digestibility of nutrients. In experiment 2, the lyophilized porcine ileal digesta from 3 barrows (Duroc × Landrace × Yorkshire, 27.75 ±â€…1.46 kg) fed the low-tannin sorghum grain without or with 30 mg/g sorghum tannin extract and the undigested residues from experiment 1 were, individually, incubated with fresh pig cecal digesta as inoculums for 48 h to simulate the porcine hindgut fermentation. The results revealed that sorghum tannin extract decreased in vitro digestibility of nutrients both by pepsin hydrolysis or pepsin-pancreatin hydrolysis (P < 0.05). Although enzymatically unhydrolyzed residues provided more energy (P = 0.09) and nitrogen (P < 0.05) as fermentation substrates, the microbial degradation of nutrients from unhydrolyzed residues and porcine ileal digesta were both decreased by sorghum tannin extract (P < 0.05). Regardless of unhydrolyzed residues or ileal digesta as fermentation substrates, microbial metabolites including the accumulative gas production excluding the first 6 h, total short-chain fatty acid and microbial protein content in the fermented solutions were decreased (P < 0.05). The relative abundances of Lachnospiraceae AC2044 and NK4A136 and Ruminococcus_1 was decreased by sorghum tannin extract (P < 0.05). In conclusion, sorghum tannin extract not only directly decreased the chemical enzymatic digestion of nutrients in the simulated anterior intestine, but also directly inhibited the microbial fermentation including microbial diversities and metabolites in the simulated posterior intestine of pigs. The experiment implies that the decreased abundances of Lachnospiraceae and Ruminococcaceae by tannins in the hindgut may weaken the fermentation capacity of microflora and thus impair the nutrient digestion in the hindgut, and ultimately reduce the total tract digestibility of nutrients in pigs fed high tannin sorghum.

Sorghum tannins may be potent negative factor to impede the nutrient utilization in sorghum grain fed to pigs. Unfortunately, the site, rate and extent of digestion of sorghum nutrients affected by tannins in the intestine remain unclear. Therefore, this experiment was conducted to determine the effects of sorghum tannin extract on the digestion and fermentation characteristics of nutrients in the in vitro simulated porcine gastrointestinal tract. The results revealed that sorghum tannin extract decreased the chemical enzymatic digestion of nutrients in the simulated anterior intestine, and inhibited the hindgut microbial fermentation including microbial diversities and metabolites (accumulative gas and short-chain fatty acid production) in the simulated posterior intestine of pigs. The experiment implies that the decreased abundances of Lachnospiraceae and Ruminococcaceae by tannins in the hindgut may weaken the fermentation capacity of microflora and thus impair the nutrient digestion in the hindgut, and ultimately may reduce the total tract nutrient digestibility in pigs fed high tannin sorghum.

Further slowing down of hydrolysis of amylose heated with black soybean extract by treating with nitrite under gastric conditions.

Black soybean (BSB), which contains cyanidin-3-O-glucoside (C3G) and procyanidins, is cooked with rice in Japan. The color of the cooked rice is purplish red due to the binding of C3G and reddish oxidation products of procyanidins. These components can slowdown pancreatin-induced hydrolysis of amylose more significantly than the hydrolysis of amylopectin, and can react with nitrous acid in the stomach. This manuscript deals with the effects of nitrous acid on pancreatin-induced hydrolysis of amylose heated with BSB extract. The hydrolysis of amylose heated with BSB extract was slow, and the slowdown was due to the binding of C3G/its degradation products and degradation products of procyanidins. The amylose hydrolysis was slowed down further by treating with nitrite under gastric conditions. The further slowdown was discussed to be due to the binding of the products, which were formed by the reaction of procyanidins with nitrous acid, to amylose. In the products, dinitroprocyanidins were included. In this way, the digestibility of amylose heated with BSB extract can be slowed down further by reacting with nitrous acid in the stomach.

Fungal digestive enzymes promote macronutrient hydrolysis in the INFOGEST static in vitro simulation of digestion.

The objective of this study was to test the hydrolytic efficacy of 6 fungal enzymes in the INFOGEST static in vitro simulation of gastrointestinal (GI) digestion. First, the INFOGEST protocol was adapted for testing of exogenous enzymes. Second, a dose-response study of 3 individual fungal proteases, a lipase, and an amylase with glucoamylase demonstrated improved dietary protein, lipid, and carbohydrate hydrolysis, respectively, from an oral nutritional supplement (ONS) under simulated gastric or GI conditions, compared to pepsin and pancreatin-based control conditions. Third, a combination of the 6 enzymes (BC-006) improved macronutrient digestion, including enhanced release of individual amino acids from ONS and mixed meal substrates. Finally, we validated digestive models of aging and proton pump inhibitor (PPI) use, and showed that BC-006 improved gastric digestion under these compromised digestive conditions. The INFOGEST static simulation is a feasible tool to rapidly screen and profile exogenous enzymes for digestive efficacy in vitro.

In vitro digestion characteristics of cereal protein concentrates as assessed using a pepsin-pancreatin digestion model.

An alkaline extraction method has been used in many studies to extract total protein from cereal samples. Wheat bran protein concentrate (WBPC), oat bran protein concentrate (OBPC), and barley protein concentrate (BPC) were prepared by alkaline extraction and isoelectric precipitation to study their functional and nutritional properties. The three protein concentrates were hydrolysed by an in vitro pepsin-pancreatin digestion model. Their digestibility (%) and degree of hydrolysis (DH%) were evaluated, and SDS-PAGE electrophoresis was used to illustrate the protein and peptides patterns. The change of the particle sizes and the release of the essential amino acids was followed during the digestion process. The in vitro digestibility of WBPC, OBPC and BPC was 87.4%, 96.1% and 76.9%, respectively. The DH% of protein concentrates were between 50 and 60%. The change of the particle size distribution values Dv(50) was assumed to be related to protein aggregations during the digestion. The protein fractions were identified and the degradation during the digestion and were analysed by SDS-PAGE; the gels of WBPC and OBPC digestion showed virtually complete degradation whereas the intensive bands of undigested protein were presented for BPC. The generation of the free amino acids and short chain peptides were significantly higher at the end of the intestinal digestion compared to the stages of before and after gastric digestion. Higher content of the deficient amino acids such as lysine and threonine were found comparing to the level of deficient amino acids in cereal grains but does not meet the daily recommended intake.

The Procyanidin C1-Dependent Inhibition of the Hydrolysis of Potato Starch and Corn Starch Induced by Pancreatin.

Procyanidins are contained in various foods, and their effects on starch hydrolysis have been reported. In Japan, black soybeans, which contain a trimeric procyanidin, procyanidin C1 (proC1), are cooked with rice and used to prepare dumplings. In this study, the effects of proC1 on the pancreatin-induced formation of reducing sugars and starch hydrolysis were studied using potato starch and corn starch. ProC1 inhibited both reactions; the inhibition was greater in potato starch than corn starch when added to heated potato starch and corn starch. When heated with proC1, its inhibitory effects decreased, especially in potato starch, suggesting the important role of proC1 itself for the inhibition of potato starch hydrolysis. ProC1 also inhibited the hydrolysis when added to heated, longer amylose (average molecular weight: 31,200), and the inhibition decreased when heated with the amylose. On the other hand, proC1 could not inhibit the hydrolysis when added to heated, shorter amylose (average molecular weight: 4500), but could when heated with the amylose, suggesting the important role of the degradation products of proC1 for the inhibition. We discuss the mechanism of the proC1-dependent inhibition of amylose hydrolysis, taking the molecular weight into account.

Do Macrocyclic Peptide Drugs Interact with Bile Salts under Simulated Gastrointestinal Conditions?

Peptide drugs face several barriers to oral delivery, including enzymatic degradation in the gastrointestinal tract and low membrane permeability. Importantly, the direct interaction between various biorelevant colloids (i.e., bile salt micelles and bile salt-phospholipid mixed micelles) present in the aqueous gastrointestinal environment and peptide drug molecules has not been studied. In this work, we systematically characterized interactions between a water-soluble model peptide drug, octreotide, and a range of physiologically relevant bile salts in solution. Octreotide membrane flux in pure bile salt solutions and commercially available biorelevant media, i.e., fasted state simulated intestinal fluid (FaSSIF) and fed state simulated intestinal fluid (FeSSIF), was evaluated using a side-by-side diffusion cell equipped with a cellulose dialysis membrane. All seven micellar bile salt solutions as well as FaSSIF and FeSSIF decreased octreotide membrane flux, and dihydroxy bile salts were found to have a much larger effect than trihydroxy bile salts. An inverse relationship between octreotide membrane flux and pancreatic enzymatic stability was also observed; bile salt micelles and bile salt-phospholipid mixed micelles provided a protective effect toward enzymatic degradation and prolonged octreotide half-life in vitro. Diffusion ordered nuclear magnetic resonance (DOSY NMR) spectroscopy and dynamic light scattering (DLS) were used as complementary experimental techniques to confirm peptide-micelle interactions in solution. Experiments were also performed using desmopressin as a second model peptide drug; desmopressin interacted with bile salts in solution, albeit to a lower extent relative to octreotide. The findings described herein demonstrate that amphiphilic, water-soluble peptide drugs do interact with bile salts and phospholipids in solution, with an effect on peptide membrane flux and enzymatic stability. Correspondingly, oral peptide drug absorption and bioavailability may be impacted.

In vitro intestinal digestion of lipids from the marine diatom Porosira glacialis compared to commercial LC n-3 PUFA products.

Marine sources of long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) are in high demand for use in health supplements. Mass cultivated marine microalgae is a promising and sustainable source of LC n-3 PUFA, which relieves pressure on natural fish stocks. The lipid class profile from cultivated photosynthetic algae differ from the marine organisms currently used for the production of LC n-3 PUFA. The objective of this study was to compare in vitro intestinal digestion of oil extracted from the cold-adapted marine diatom Porosira glacialis with commercially available LC n-3 PUFA supplements; cod liver oil, krill oil, ethyl ester concentrate, and oil from the copepod Calanus finmarchicus (Calanus® oil). The changes in the free fatty acids and neutral and polar lipids during the enzymatic hydrolysis were characterized by liquid and gas chromatography. In Calanus® oil and the Ethyl ester concentrate, the free fatty acids increased very little (4.0 and 4.6%, respectively) during digestion. In comparison, free fatty acids in Krill oil and P. glacialis oil increased by 14.7 and 17.0%, respectively. Cod liver oil had the highest increase (28.2%) in free fatty acids during the digestion. Monounsaturated and saturated fatty acids were more easily released than polyunsaturated fatty acids in all five oils.

Investigating the Impact of Crohn's Disease on the Bioaccessibility of a Lipid-Based Formulation with an In Vitro Dynamic Gastrointestinal Model.

The aim of the study was to investigate the impact of Crohn's disease (CD) on the performance of a lipid-based formulation of ciprofloxacin in a complex gastrointestinal simulator (TIM-1, TNO) and to compare the luminal environment in terms of bile salt and lipid composition in CD and healthy conditions. CD conditions were simulated in the TIM-1 system with a reduced concentration of porcine pancreatin and porcine bile. The bioaccessibility of ciprofloxacin was similar in simulated CD and healthy conditions considering its extent as well as its time course in the jejunum and ileum filtrate. Differences were observed in terms of the luminal concentration of triglycerides, monoglycerides, and fatty acids in the different TIM-1 compartments, indicating a reduction and delay in the lipolysis of formulation excipients in CD. The quantitative analysis of bile salts revealed higher concentrations for healthy conditions (standard TIM-1 fasted-state protocol) in the duodenum and jejunum TIM-1 compartments compared to published data in human intestinal fluids of healthy subjects. The reduced concentrations of bile salts in simulated CD conditions correspond to the levels observed in human intestinal fluids of healthy subjects in the fasted state.A lipidomics approach with ultra performance liquid chromatography (UPLC)/mass spectrometry (MS) has proven to be a time-efficient method to semiquantitatively analyze differences in fatty acid and bile salt levels between healthy and CD conditions. The dynamic luminal environment in CD and healthy conditions after administration of a lipid-based formulation can be simulated using the TIM-1 system. For ciprofloxacin, an altered luminal lipid composition had no impact on its performance indicating a low risk of altered performance in CD patients.

Physicochemical, functional and bioactive properties of hempseed (Cannabis sativa L.) meal, a co-product of hempseed oil and protein production, as affected by drying process.

Hempseed meal after protein isolation (HM-PI) is a co-product obtained from hempseed. The objectives were to characterize and determine the effect of drying on HM-PI. HM-PI was produced using three drying methods: freeze (FD), vacuum oven (VOD), and oven drying (OD). HM-PI contained over 70% protein and had similar or higher level of essential amino acids than recommended values for human adults. Osborne fractionation indicated that glutelin was the most dominant fraction in HM-PI. FD HMPI has a significant lower surface hydrophobicity and higher in vitro protein digestibility than OD and VOD HM-PI. FD HM-PI demonstrated better functional properties than OD and VOD HM-PI. Pepsin-pancreatin digestion of VOD, FD and OD resulted in comparable and considerable antioxidant and anti-inflammatory properties. This is the first report on the characterization of HM-PI, a co-product of hempseed processing. HM-PI could serve as a novel food protein ingredient resulting in increase utilization of hempseed.

In vitro digestion of salmon: Influence of processing and intestinal conditions on macronutrients digestibility.

Salmon is the main dietary source of omega-3 lipids and contains high-biological value protein. However, processing techniques could affect macronutrient digestibility. Also, altered intestinal conditions, particularly given in pancreatic insufficiency, could threaten digestibility. This study tested both hypotheses by subjecting raw, marinated and microwave-cooked salmon to static in vitro digestion under healthy (pH 7, bile concentration 10 mM) and altered (pH 6, bile 1 or 10 mM) intestinal conditions with different pancreatin concentrations. In the standard conditions, proteolysis was not affected by processing, but lipolysis decreased in marinated (46%) and raw salmon (57%) compared to the cooked matrix (67%). In altered conditions, proteolysis and lipolysis decreased to different extents depending on the treatment. Overall, processing affected proteolysis the most (f-ratio = 5.86), while intestinal conditions were the major determinants of lipolysis (f-ratio = 58.01). This study could set the ground to establish dietary recommendations of salmon for specific population groups.

Anti-inflammatory and antioxidant effects of peptides released from germinated amaranth during in vitro simulated gastrointestinal digestion.

Amaranth (Amaranthus hypochondriacus) is an ancestral nutritional grain and good source of bioactive compounds as peptides. In this study, the effect of in vitro simulated gastrointestinal digestion (SGD) of germinated amaranth on the release of antioxidant and anti-inflammatory peptides was evaluated. The germinated amaranth peptides generated during SGD were released after 90 min of incubation with pancreatin and fractioned to F1 (>10 kDa), F2 (3-10 kDa), and F3 (<3 kDa). Among germinated amaranth peptides fractions tested, F2 had the highest antioxidant activity, while F1 and F2 exhibited a high anti-inflammatory response caused by lipopolysaccharide-induced in RAW 264.7 macrophages. A total of 11 peptides sequences were identified in the fractions evaluated, and they exhibit potential biological activity against non-communicable diseases. The findings from this study showed first time report on bioactive peptides, especially anti-inflammatory, from germinated amaranth released by in vitro gastrointestinal digestion.

Differences in In Vitro Properties of Pancreatin Preparations for Pancreatic Exocrine Insufficiency as Marketed in Russia and CIS.

BACKGROUND: Pancreatic enzyme-replacement therapy (PERT), provided as pancreatin to patients with pancreatic exocrine insufficiency (PEI), is considered an essential substitute for the pivotal physiological function the pancreas fulfills in digestion. PEI involves a reduction in the synthesis and secretion of pancreatic enzymes (lipase, protease, amylase), which leads to an inadequate enzymatic response to a meal and consequently to maldigestion and malabsorption of nutrients. The efficacy of PERT is strongly dependent on enzyme activity, dissolution, and pancreatin particle size. OBJECTIVE: The physiological properties of eight pancreatin preparations (nine batches; five different brands) available in Russia and CIS (Commonwealth of Independent States: Armenia, Azerbaijan, Belarus, Kazakhstan, Kyrgyzstan, Moldova, Russia, Tajikistan, Uzbekistan) were investigated. METHODS: The lipase activity, dissolution, and particle size distribution of samples from multiple batches of pancreatin of different strengths were measured. RESULTS: Regarding lipase activities, all pancreatin preparations except Micrazim® matched the labeled content. Considerable differences were observed in particle size and dissolution. CONCLUSION: Pancreatin preparations available in Russia and CIS demonstrate product-to-product and batch-to-batch variability regarding the measured properties of lipase activity, dissolution, and particle size. This may impact the efficacy of PERT and therefore clinical outcomes.

Phosvitin Derived Phospho-Peptides Show Better Osteogenic Potential than Intact Phosvitin in MC3T3-E1 Osteoblastic Cells.

Phosphorylated proteins from food sources have been investigated as regulators of bone formation with potential benefits in treating osteoporosis. Egg, a cheap and nutritious food, is also the source of various proteins and bioactive peptides with applications in human health. Egg yolk is rich in phosvitin, the most phosphorylated protein in nature. Phosvitin has been shown to improve bone health in experimental animals, although the molecular mechanisms and its specific effects on bone-forming osteoblastic cells are incompletely understood. Previous work in our group has identified pancreatin-generated phosvitin phospho-peptides (PPP) as a potential source for bioactive peptides. Given this background, we examined the roles of both phosvitin and PPP in the function of osteoblastic cells. Our results demonstrated their potential to improve bone health by promoting osteoblast differentiation and proliferation, suppressing osteoclast recruitment and the deposition of extracellular matrix, although PPP appeared to demonstrate superior osteogenic functions compared to phosvitin alone.

Accumulation of storage proteins in plant seeds is mediated by amyloid formation.

Amyloids are protein aggregates with a highly ordered spatial structure giving them unique physicochemical properties. Different amyloids not only participate in the development of numerous incurable diseases but control vital functions in archaea, bacteria and eukarya. Plants are a poorly studied systematic group in the field of amyloid biology. Amyloid properties have not yet been demonstrated for plant proteins under native conditions in vivo. Here we show that seeds of garden pea Pisum sativum L. contain amyloid-like aggregates of storage proteins, the most abundant one, 7S globulin Vicilin, forms bona fide amyloids in vivo and in vitro. Full-length Vicilin contains 2 evolutionary conserved ß-barrel domains, Cupin-1.1 and Cupin-1.2, that self-assemble in vitro into amyloid fibrils with similar physicochemical properties. However, Cupin-1.2 fibrils unlike Cupin-1.1 can seed Vicilin fibrillation. In vivo, Vicilin forms amyloids in the cotyledon cells that bind amyloid-specific dyes and possess resistance to detergents and proteases. The Vicilin amyloid accumulation increases during seed maturation and wanes at germination. Amyloids of Vicilin resist digestion by gastrointestinal enzymes, persist in canned peas, and exhibit toxicity for yeast and mammalian cells. Our finding for the first time reveals involvement of amyloid formation in the accumulation of storage proteins in plant seeds.

Modulation of gastrointestinal digestion of ß-lactoglobulin and micellar casein following binding by (-)-epigallocatechin-3-gallate (EGCG) and green tea flavanols.

The effect of binding of flavonoids, (-)-epigallocatechin-3-gallate (EGCG) and green tea extract (GTE), to beta-lactoglobulin (ß-Lg) and micellar casein (micellar casein isolate, MCI) on protein digestibility was investigated. ß-Lg resisted digestion by pepsin, but in the presence of EGCG the digestion of ß-Lg was enhanced. Binding of EGCG to ß-Lg was identified by nitro blue tetrazolium (NBT) staining and found, by isothermal titration calorimetry, to be an enthalpy-driven exothermic process, with a binding constant of 19 950 L mol-1. Binding promoted a more rapid digestion of ß-Lg during simulated upper duodenal digestion. NBT staining indicated a loss of binding of EGCG to ß-Lg during combined gastric and distal small intestinal digestion and correlated with the cleavage of ß-Lg. However, increased ß-Lg heteromer formation and reduced ß-Lg monomer digestibility were observed for the ß-Lg-GTE complex. MCI was more digestible than ß-Lg during pepsin digestion, but reduced digestibility was observed for both MCI-EGCG and MCI-GTE complexes, with loss of binding during intestinal digestion. The free radical scavenging capacity (FRSC) of EGCG remained stable for the ß-Lg-EGCG complex throughout the gastric and intestinal phases of digestion, but this was significantly lowered for the MCI-EGCG complex. These results indicated that polyphenols bind to milk proteins modulating the in vitro digestibility and FRSC of ß-Lg and MCI as a result of the formation of complexes.

Suitability of Artificial Membranes in Lipolysis-Permeation Assays of Oral Lipid-Based Formulations.

PURPOSE: To evaluate the performance of artificial membranes in in vitro lipolysis-permeation assays useful for absorption studies of drugs loaded in lipid-based formulations (LBFs). METHODS: Polycarbonate as well as PVDF filters were treated with hexadecane, or lecithin in n-dodecane solution (LiDo) to form artificial membranes. They were thereafter used as absorption membranes separating two compartments mimicking the luminal and serosal side of the intestine in vitro. Membranes were subjected to dispersions of an LBF that had been digested by porcine pancreatin and spiked with the membrane integrity marker Lucifer Yellow (LY). Three fenofibrate-loaded LBFs were used to explore the in vivo relevance of the assay. RESULTS: Of the explored artificial membranes, only LiDo applied to PVDF was compatible with lipolysis by porcine pancreatin. Formulation ranking based on mass transfer in the LiDo model exposed was the same as drug release in single-compartment lipolysis. Ranking based on observed apparent permeability coefficients of fenofibrate with different LBFs were the same as those obtained in a cell-based model. CONCLUSIONS: The LiDo membrane was able to withstand lipolysis for a sufficient assay period. However, the assay with porcine pancreatin as digestive agent did not predict the in vivo ranking of the assayed formulations better than existing methods. Comparison with a Caco-2 based assay method nonetheless indicates that the in vitro in vivo relationship of this cell-free model could be improved with alternative digestive agents.

Whey Peptides Stimulate Differentiation and Lipid Metabolism in Adipocytes and Ameliorate Lipotoxicity-Induced Insulin Resistance in Muscle Cells.

Deregulation of lipid metabolism and insulin function in muscle and adipose tissue are hallmarks of systemic insulin resistance, which can progress to type 2 diabetes. While previous studies suggested that milk proteins influence systemic glucose homeostasis and insulin function, it remains unclear whether bioactive peptides generated from whey alter lipid metabolism and its accumulation in muscle and adipose tissue. Therefore, we incubated murine 3T3-L1 preadipocytes and C2C12 myotubes with a whey peptide mixture produced through pepsin-pancreatin digestion, mimicking peptides generated in the gut from whey protein hydrolysis, and examined its effect on indicators of lipid metabolism and insulin sensitivity. Whey peptides, particularly those derived from bovine serum albumin (BSA), promoted 3T3-L1 adipocyte differentiation and triacylglycerol (TG) accumulation in accordance with peroxisome proliferator-activated receptor γ (PPARγ) upregulation. Whey/BSA peptides also increased lipolysis and mitochondrial fat oxidation in adipocytes, which was associated with the upregulation of peroxisome proliferator-activated receptor δ (PPARδ). In C2C12 myotubes, whey but not BSA peptides ameliorated palmitate-induced insulin resistance, which was associated with reduced inflammation and diacylglycerol accumulation, and increased sequestration of fatty acids in the TG pool. Taken together, our study suggests that whey peptides generated via pepsin-pancreatin digestion profoundly alter lipid metabolism and accumulation in adipocytes and skeletal myotubes.

Contribution of amylose-procyanidin complexes to slower starch digestion of red-colored rice prepared by cooking with adzuki bean.

Combining high-carbohydrate food with polyphenol-rich food is a possible way of producing slowly digestible starch with beneficial health properties. In Japan, non-glutinous and glutinous rice are cooked with adzuki bean and the colour of the cooked rice is pale red. In this article, we show that (1) the red colour of rice could be attributed to the oxidation of adzuki bean procyanidins, (2) pancreatin-induced starch digestion of the red-coloured non-glutinous rice was slower than white rice and (3) the digestion of amylose and potato starch but not amylopectin became slower by heating with procyanidin B2. Furthermore, the rate of starch digestion of red-coloured rice was not affected by nitrite treatment under simulated gastric conditions. The above results show that procyanidins could bind to amylose independent of the starch source by heating and could suppress starch digestion by α-amylase in the intestine.

Effect of heating on the digestibility of isolated hempseed (Cannabis sativa L.) protein and bioactivity of its pepsin-pancreatin digests.

The objective was to investigate the effects of heat pretreatment and simulated gastrointestinal digestion on potential antioxidant, anticancer and anti-inflammatory activities of hempseed (Cannabis sativa L.) proteins. Unheated isolated hempseed protein (IHP) and its heated counterparts (100 °C, 15 min and 30 min, termed as HP15D and HP30D) were hydrolyzed sequentially with pepsin and pancreatin and analyzed for digestibility and bioactivity (antioxidant, anti-proliferative and anti-inflammatory properties). Heat pretreatment led to an increase of low molecular weight proteins and degree of hydrolysis, and decrease of concentration of soluble protein, which means heat pretreated can significantly improve the digestibility of IHP. Pepsin-pancreatin digests released from heat pretreated IHP possessed less antioxidant, antiproliferative and anti-inflammatory properties than digests from unheated IHP. In conclusion, heat pre-treatment improved the digestibility of IHP but the resulting digests from heated IHP had lower bioactivity.