Role of Ca2+ in the pepsin-induced coagulation and in the dynamic in vitro gastric digestion behavior of casein micelles.

The effect of Ca2+ on pepsin-induced hydrolysis of κ-casein and subsequent coagulation of casein micelles was studied in a micellar casein (MC) solution at pH ≈ 6.0 at 37 °C without stirring. An NaCl-supplemented MC solution was used as a positive control to assess the effect of increased ionic strength after CaCl2 addition. Quantitative determination of the released para-κ-casein during the reaction using reverse-phase high-performance liquid chromatography showed that specific hydrolysis of κ-casein by pepsin was little affected by the addition of either CaCl2 or NaCl. However, rheological properties and microstructures of curds induced by pepsin hydrolysis depended markedly on the addition of salts. Addition of CaCl2 up to 17.5 mM facilitated coagulation, with decreases in coagulation time and critical hydrolysis degree, and increases in firming rate and maximum storage modulus (G'max); further addition of CaCl2 (22.5 mM) resulted in a lower G'max. Increased ionic strength to 52.5 mM by adding NaCl retarded the coagulation and resulted in a looser curd structure. In a human gastric simulator, MC, without the addition of CaCl2, did not coagulate until the pH decreased to ≈5.0 after ≈50 min of digestion. Addition of CaCl2 facilitated coagulation of casein micelles and resulted in more cohesive curds with dense structures during digestion, which slowed the emptying rate of caseins. At the same CaCl2 concentration, a sample with higher ionic strength coagulated more slowly. This study provides further understanding on the effect of divalent (Ca2+) ions and ionic strength on the coagulation of casein micelles and the digestion behavior of milk.

Cholesterol stabilization of phospholipid vesicles against bile-induced solubilization.

Sphingomyelin (SM) and cholesterol complex to form functional liquid-ordered (Lo) domains. It has been suggested that the detergent resistance of these domains plays a key role during gastrointestinal digestion of the milk fat globule membrane (MFGM), which is rich in both SM and cholesterol. Small-angle X-ray scattering was employed to determine the structural alterations that occur when milk sphingomyelin (MSM)/cholesterol, egg sphingomyelin (ESM)/cholesterol, soy phosphatidylcholine (SPC)/cholesterol, and milk fat globule membrane (MFGM) phospholipid/cholesterol model bilayer systems were incubated with bovine bile under physiological conditions. The persistence of diffraction peaks was indicative of multilamellar vesicles of MSM with cholesterol concentrations > 20 % mol, and also for ESM with or without cholesterol. The complexation of ESM with cholesterol is therefore capable of inhibiting the resulting vesicles from disruption by bile at lower cholesterol concentrations than MSM/cholesterol. After subtraction of background scattering by large aggregates in the bile, a Guinier fitting was used to determine changes in the radii of gyration (Rgs) over time for the biliary mixed micelles after mixing the vesicle dispersions with bile. Swelling of the micelles by phospholipid solubilization from vesicles was a function of cholesterol concentration, with less swelling of the micelles occurring as the cholesterol concentration was increased. With 40% mol cholesterol, the Rgs of the bile micelles mixed with MSM/cholesterol, ESM/cholesterol, and MFGM phospholipid/cholesterol were equal to the control (PIPES buffer + bovine bile), indicating negligible swelling of the biliary mixed micelles.

Plant oil bodies and their membrane components: new natural materials for food applications.

Plants store triacylglycerols in the form of oil bodies (OBs) as an energy source for germination and subsequent seedling growth. The interfacial biomaterials from these OBs are called OB membrane materials (OBMMs) and have several applications in foods, e.g., as emulsifiers. OBMMs are preferred, compared with their synthetic counterparts, in food applications as emulsifiers because they are natural, i.e., suitable for clean label, and may stabilize bioactive components during storage. This review focuses mainly on the extraction technologies for plant OBMMs, the functionality of these materials, and the interaction of OB membranes with other food components. Different sources of OBs are evaluated and the challenges during the extraction and use of these OBMMs for food applications are addressed.

Autologous Blood Injection With Dry-Needling vs Dry-Needling Alone Treatment for Chronic Plantar Fasciitis: A Randomized Controlled Trial.

BACKGROUND: Autologous blood injection (ABI) for patients with chronic plantar fasciitis has been promoted as an approach to improve outcomes over standard dry-needling approaches. The purpose of this trial was to investigate if there are improved outcomes following an ultrasonography-guided ABI compared to dry needling alone for patients with chronic plantar fasciitis. METHODS: A double-blinded (participant-blinded and observer-blinded) RCT within a single clinic enrolled 90 patients with symptoms of plantar fasciitis that had failed to improve with a minimum of 3 months of rehabilitation. The mean age was 49.5±8.9 years, 67% were female, and the mean symptom duration was 40.0±28.2 months (range: 8 months-10 years). Participants were randomized to receive ABI or an identical dry-needle fenestration-procedure without coadministration of autologous blood. All participants received identical structured rehabilitation and were followed up at 2, 6, 12, and 26 weeks. Outcome measures included local foot pain, validated foot patient-reported outcome measures (Foot Function Index-revised, Manchester-Oxford Foot Questionnaire, Foot and Ankle Ability Measure), measures of general function and "ability" (EuroQol [EQ]-5D-5L, Oswestry Disability Index), specific measures of activity (International Physical Activity Questionnaire), sleep (Pittsburgh Sleep Quality Index), and mood (Hospital Anxiety and Depression Scale). RESULTS: There were no significant between-group differences seen at any time-point studied. There were a number of statistically significant within-group improvements for local foot pain and function in both groups comparing baseline/follow-up data. Overall, levels of pain improved by 25% by 6 weeks and by 50% at 6 months. There were improvements in some generalized function markers. Activity rates did not change, demonstrating that improvements in pain did not necessarily influence physical activity. CONCLUSION: Coadministration of 3 mL of autologous blood had no additional effect compared to a dry-needling procedure alone for patients with chronic plantar fasciitis. LEVEL OF EVIDENCE: Level I, double-blinded randomized controlled trial.

Therapeutic Potential of Mitophagy-Inducing Microflora Metabolite, Urolithin A for Alzheimer's Disease.

Mitochondrial dysfunction including deficits of mitophagy is seen in aging and neurodegenerative disorders including Alzheimer's disease (AD). Apart from traditionally targeting amyloid beta (Aß), the main culprit in AD brains, other approaches include investigating impaired mitochondrial pathways for potential therapeutic benefits against AD. Thus, a future therapy for AD may focus on novel candidates that enhance optimal mitochondrial integrity and turnover. Bioactive food components, known as nutraceuticals, may serve as such agents to combat AD. Urolithin A is an intestinal microbe-derived metabolite of a class of polyphenols, ellagitannins (ETs). Urolithin A is known to exert many health benefits. Its antioxidant, anti-inflammatory, anti-atherogenic, anti-Aß, and pro-mitophagy properties are increasingly recognized. However, the underlying mechanisms of urolithin A in inducing mitophagy is poorly understood. This review discusses the mitophagy deficits in AD and examines potential molecular mechanisms of its activation. Moreover, the current knowledge of urolithin A is discussed, focusing on its neuroprotective properties and its potential to induce mitophagy. Specifically, this review proposes potential mechanisms by which urolithin A may activate and promote mitophagy.

Postprandial lipaemia following consumption of a meal enriched with medium chain saturated and/or long chain omega-3 polyunsaturated fatty acids. A randomised cross-over study.

BACKGROUND & AIMS: Postprandial lipaemic response has emerged as a risk factor for cardiovascular disease. Dietary fats such as medium-chain saturated fatty acids (MCSFA) and long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFA) are known to reduce postprandial lipaemic responses. The combination of the two could potentially have complementary and/or synergistic effects for optimising cardiovascular health. This study aims to investigate the effects of MCSFA (coconut oil) with or without LCn-3PUFA (fish oil) inclusion in the test meal on postprandial blood lipids in healthy adults. METHODS: In a randomised, double-blinded, placebo-controlled, 2 × 2 factorial cross-over study, participants (n = 15) were randomised to receive four standardised isocaloric test meals. Test meals include: placebo [PL, containing no fish oil (0 g EPA & DHA) or coconut oil (0 g MCSFA)], fish oil [FO, 6 g fish oil (3.85 g EPA & DHA), containing no coconut oil (0 g MCSFA)], coconut oil [CO, 18.65 g coconut oil (15 g MCSFA), containing no fish oil (0 g EPA & DHA)] and coconut oil + fish oil [COFO, 18.65 g coconut oil (15 g MCSFA) + 6 g fish oil (3.85 g EPA & DHA)]; all providing a total fat content of 33.5 g. Participants received all four treatments on four separate test days with at least 3 days washout in between. Blood parameters were measured by finger pricks at 7 timepoints between 0 and 300min. The primary outcome of this study was the change in postprandial triglycerides (TG) concentrations with secondary outcomes as total cholesterol, high-density lipoprotein cholesterol and blood glucose concentrations. RESULTS: TG area under the curve (AUC) (mmol/L/min) was significantly lower for FO (383.67, p = 0.0125) and COFO (299.12, p = 0.0186) in comparison to PL (409.17) only. TG incremental area under the curve (iAUC) (mmol/L/min) was significantly lower with COFO (59.67) in comparison to CO (99.86), (p = 0.0480). Compared to PL, the change in absolute TG concentrations (mmol/L) from baseline to post TG peak time (180min) after FO were significantly less at 240min (0.39 vs 0.15), 270min (0.2 vs 0.1), and 300min (0.28 vs 0.06), and after COFO was significantly less at 300min (0.28 vs 0.16) (p < 0.05). No significant differences in postprandial AUC and iAUC for any other blood parameters were reported. CONCLUSIONS: Our study demonstrated that LCn-3PUFA with or without MCSFA but not MCSFA alone are effective in reducing postprandial TG in healthy individuals.

Impact of Ascorbic Acid on the In Vitro Iron Bioavailability of a Casein-Based Iron Fortificant.

A new iron-casein complex (ICC) has been developed for iron (Fe) fortification of dairy matrices. The objective was to assess the impact of ascorbic acid (AA) on its in vitro bioavailability in comparison with ferrous sulfate (FeSO4) and ferric pyrophosphate (FePP). A simulated digestion coupled with the Caco-2 cell culture model was used in parallel with solubility and dissociation tests. Under diluted acidic conditions, the ICC was as soluble as FeSO4, but only part of the iron was found to dissociate from the caseins, indicating that the ICC was an iron chelate. The Caco-2 cell results in milk showed that the addition of AA (2:1 molar ratio) enhanced iron uptake from the ICCs and FeSO4 to a similar level (p = 0.582; p = 0.852) and to a significantly higher level than that from FePP (p < 0.01). This translated into a relative in vitro bioavailability to FeSO4 of 36% for FePP and 114 and 104% for the two ICCs. Similar results were obtained from water. Increasing the AA to iron molar ratio (4:1 molar ratio) had no additional effect on the ICCs and FePP. However, ICC absorption remained similar to that from FeSO4 (p = 0.666; p = 0.113), and was still significantly higher than that from FePP (p < 0.003). Therefore, even though iron from ICC does not fully dissociate under gastric digestion, iron uptake suggested that ICCs are absorbed to a similar amount as FeSO4 in the presence of AA and thus provide an excellent source of iron.

Structural and physicochemical changes in almond milk during in vitro gastric digestion: impact on the delivery of protein and lipids.

Almond milk (about 3% protein and 7% lipids) was prepared using wet disintegration of raw almonds and then subjected to in vitro gastric digestion using an advanced dynamic digestion model (i.e., a human gastric simulator). Microstructural changes, physicochemical behavior, and protein digestion were examined; the release of lipids and protein during digestion was quantified. Under acidic gastric conditions, almond oil bodies flocculated. Proteolysis by pepsin led to destabilization and coalescence of the oil bodies, resulting in creaming and phase separation. This phase separation significantly delayed the delivery of lipids to the small intestine. After 225 min of digestion, ∼42% of the lipids remained in the stomach. In contrast, protein release was not significantly affected by the gastric behavior of the almond oil bodies. This study provides a better understanding of how the digestive system manages plant lipids, and may be useful in the microstructural design of foods to achieve a controlled physiological response during digestion.

Food matrix and co-presence of turmeric compounds influence bioavailability of curcumin in healthy humans.

The natural food-derived compound curcumin (from turmeric root) is known for its anti-inflammatory and anti-oxidant effects. However, due to its poor solubility when consumed in isolation, it is poorly bioavailable. In this crossover study we compared the bioavailability of curcumin from a meal containing either curcumin powder, turmeric powder or grated fresh turmeric root, all containing 400 mg of curcumin, along with mashed potatoes and cream. Healthy male participants consumed the meals following overnight fasting, and postprandial blood samples were taken to measure plasma curcuminoids (curcumin, dimethylcurcumin (DMC) and bisdimethylcurcumin (BDMC)). All plasma curcumin values refer to total curcumin (sum of free and conjugated curcumin). The meals were also analysed using confocal laser scanning microscopy to determine the location of curcuminoids. Both of the turmeric meals produced significantly higher amounts (p < 0.05) of plasma curcuminoids at 1-3 hours after the meal was consumed, as compared to the curcumin powder. Plasma curcumin Cmax was 4.9 ng ml-1 95% CI (confidence interval) [2.2, 7.5] for the fresh turmeric meal, 8.4 ng ml-1 95% CI [4.4, 12.48] for the turmeric powder meal and 0.19 ng ml-1 95% [-0.08, 0.47] for the curcumin powder meal. Plasma DMC and BDMC were significantly higher (p < 0.05) following the turmeric powder meal, compared with the fresh turmeric meal and the curcumin powder meal. Microscopy images showed that the curcuminoid particles were mostly confined within curcuminoid cells in the fresh turmeric meal. They were unconfined but in clusters in the turmeric powder meal, while the curcuminoid particles appeared smaller in the curcumin powder meal. Conclusion: curcumin bioavailability is enhanced when consumed as fresh or powdered turmeric, which could be due to the co-presence of other turmeric compounds and/or a turmeric matrix effect.

Droplet-Stabilized Oil-in-Water Emulsions Protect Unsaturated Lipids from Oxidation.

Droplet-stabilized emulsions use fine protein-coated lipid droplets (the shell) to emulsify larger droplets of a second lipid (the core). This study investigated the oxidation resistance of polyunsaturated fatty acid (PUFA) oil within droplet-stabilized emulsions, using shell lipids with a range of melting points: olive oil (low melting), trimyristin (high-melting), and palmolein oil (intermediate melting point). Oxidation of PUFA oil was accelerated with a fluorescent lamp in the presence of ferrous iron (100 µM) for 9 days, and PUFA oxidation was monitored via conjugated dienes, lipid hydroperoxides, and hexanal levels. Oxidation was slower in droplet-stabilized emulsions than in conventional emulsions or control emulsions of the same composition as droplet-stabilized emulsions but different structure, and trimyristin gave the greatest oxidation resistance. Results suggest the structured interface of droplet-stabilized emulsions limits contact between pro-oxidants and oxidation-sensitive bioactives encapsulated within, and this antioxidative effect is greatly enhanced with solid surface lipids.

Diabetes and Alzheimer's Disease: Can Tea Phytochemicals Play a Role in Prevention?

Dementia and diabetes mellitus are prevalent disorders in the elderly population. While recognized as two distinct diseases, diabetes has more recently recognized as a significant contributor to risk for developing dementia, and some studies make reference to type 3 diabetes, a condition resulting from insulin resistance in the brain. Alzheimer's disease, the most common form of dementia, and diabetes, interestingly, share underlying pathological processes, commonality in risk factors, and, importantly, pathways for intervention. Tea has been suggested to possess potent antioxidant properties. It is rich in phytochemicals including, flavonoids, tannins, caffeine, polyphenols, boheic acid, theophylline, theobromine, anthocyanins, gallic acid, and finally epigallocatechin-3-gallate, which is considered to be the most potent active ingredient. Flavonoid phytochemicals, known as catechins, within tea offer potential benefits for reducing the risk of diabetes and Alzheimer's disease by targeting common risk factors, including obesity, hyperlipidemia, hypertension, cardiovascular disease, and stroke. Studies also show that catechins may prevent the formation of amyloid-ß plaques and enhance cognitive functions, and thus may be useful in treating patients who have Alzheimer's disease or dementia. Furthermore, other phytochemicals found within tea offer important antioxidant properties along with innate properties capable of modulating intracellular neuronal signal transduction pathways and mitochondrial function.

Microstructural characteristics and gastro-small intestinal digestion in vitro of potato starch: Effects of refrigerated storage and reheating in microwave.

The objective of our study was to evaluate paste clarity, retrogradation (syneresis %), thermal characteristics and kinetics of glucose release during in vitro gastro-small intestinal digestion of freshly cooked and refrigerated potato starch. Freshly cooked starch pastes had a paste clarity of 71%, which decreased to 35.4% whereas syneresis (%) increased after 7days of refrigerated storage. The X-ray and thermal characteristics of native, retrograded and microwave reheated starch samples differed significantly from each other. For the freshly cooked starch pastes, ∼88% starch hydrolysis was observed at the end (150min) of digestion under simulated gastro-small intestinal conditions that decreased to ∼70% for the 7day stored pastes. The hydrolysis (%) of refrigerated pastes increased to 86% and 92% after one and two cycles of microwave reheating, respectively. These results contribute to the understanding of starch retrogradation in relation to starch digestion.

Effect of food matrix microstructure on stomach emptying rate and apparent ileal fatty acid digestibility of almond lipids.

Almond lipids can be consumed in different forms such as nuts, oil-in-water emulsions or oil. The stomach emptying rate (SER) of almond lipids (0.2 g of fat per 2 mL of almond lipid suspension) as a function of the food matrix was studied using magnetic resonance spectroscopy based on the stomach emptying of a marker (AlCl3-6H2O) in the growing rat. Chyme and digesta samples were collected following serial gavaging (0.2 g of fat per 2 mL of almond lipid suspension) to study microstructural changes and determine the apparent ileal digestibility of almond fatty acids as a function of the native food matrix. The T(1/2) for the stomach emptying of crushed whole almonds and almond cream (194 ± 17 min and 185 ± 19 min, respectively) were not different (P > 0.05) from that of a gastric-stable Tween-oil emulsion (197 ± 19 min). The T(1/2) values for a sodium caseinate (NaCas)-oil emulsion (145 ± 11 min) and a gastric-unstable Span-oil emulsion (135 ± 7 min) were different (P < 0.05) from those for crushed whole almonds, almond cream and Tween-oil emulsion, while almond milk and oil emptied at an intermediate rate (157 ± 9 min and 172 ± 11 min, respectively). Extensively coalesced emulsions under gastric conditions (almond oil, almond cream and Span-oil) had lower (P < 0.05) overall apparent ileal fatty acid digestibility (85.8%, 75.8% and 74.3%, respectively) than crushed whole almonds, almond milk, NaCas-oil and Tween-oil emulsions (91.0%, 92.2%, 92.1% and 88.7%, respectively). The original food matrix and structural changes occurring within the gastrointestinal tract had an impact on SER and ileal fatty acid digestibility of the almond preparations.

Korean ginseng modulates the ileal microbiota and mucin gene expression in the growing rat.

The study was conducted to investigate whether oral administration of Korean ginseng powders can modulate gut microbiota as well as intestinal mucin production at the translational and transcriptional levels in the ileum of the growing rat. Thirty individually caged Sprague-Dawley male rats were allocated to three groups (n = 10) and fed for 21 days either a basal control diet or one of the two treatment diets each containing white or red Korean ginseng (WG or RG) powder. Bacterial DNA was extracted from ileal digesta and subjected to quantitative real-time PCR (qPCR) using primers for total bacteria, Lactobacillus, Bifidobacteria, Escherichia coli, Bacteroides, and Clostridium strains. The qPCR results showed that consumption of WG or RG powder significantly increased the number of total bacteria and Lactobacillus strains compared to the control group. Consumption of WG powder increased mRNA expression of the Muc2 gene in the small intestine compared to the control group. There was no effect of WG or RG on the small intestinal digesta mucin content. Correlation analysis showed that expression of the Muc2 gene was significantly associated with the number of total bacteria (r = 0.52, P < 0.05) and Lactobacillus strains (r = 0.53, P < 0.05), respectively. Furthermore, the number of Lactobacillus strains was significantly correlated with the number of total bacteria (r = 0.87, P < 0.05). Consumption of the WG powder modulated the intestinal ecosystem of the growing rat and intestinal mucin gene expression.

Free fatty acid profiles of emulsified lipids during in vitro digestion with pancreatic lipase.

Individual free fatty acids released from milk protein-stabilized emulsions prepared with milk fat, soya bean oil or tuna fish oil during in vitro digestion with pancreatic lipase were monitored using gas chromatography. The results showed that saturated fatty acids (C16:0 and C18:0) were released faster than unsaturated fatty acids (C18:1n9, C18:2n6 and C18:3n3) from soya bean oil emulsions; short chain fatty acids were released faster than long chain fatty acids from milk fat emulsions; long chain polyunsaturated fatty acids, such as eicosapentaenoic acid and docosahexaenoic acid, were released more slowly than other fatty acids from fish oil emulsions. The results confirm that the release behaviour of fatty acids from emulsions during digestion is related not only to the position of the fatty acids in the triglycerides in the fat/oil, but also to the length of the carbon chain of the fatty acid. The rates and the extents of the digestion of lipids consisting of short chain fatty acids are higher than those of lipids consisting of long chain fatty acids.

In vitro gastric and intestinal digestion of a walnut oil body dispersion.

An oil body dispersion (11.3% fat) was prepared by wet disintegration of walnuts and was then subjected to a two-step model of in vitro digestion. In a gastric environment, proteolysis by pepsin led to the destabilization and coalescence of the oil bodies. Aggregation of the coalesced oil bodies was apparent under a confocal microscope, with aggregates up to 275 µm in size. Pepsin-resistant peptides and proteins remained at the surface of the oil bodies, and some were further resistant to intestinal proteases. Under intestinal conditions, the hydrolysis of walnut triglycerides led to the spontaneous formation of a new type of multiple emulsions, ranging from 2 to 45 µm in size and with protein material inside the inner water droplets. Transmission electron microscopy revealed the presence of a liquid-crystalline phase of bile salts and lipolytic products at the surface of the oil droplets and some bile salt crystals at the surface of the inner water droplets.

Green and gold kiwifruit peel ethanol extracts potentiate pentobarbital-induced sleep in mice via a GABAergic mechanism.

Kiwifruit is one of the most popular fruits worldwide, and it has various biological properties, including antioxidant, anti-allergic, and cardiovascular protective effects. The peel of kiwifruit, which is a by-product of processing, is a good source of flavonoids; however, its bioactivity has not been widely investigated. In this study, we evaluated the hypnotic effects of green (GRPE, Actinidia deliciosa) and gold (GOPE, Actinidia chinensis) kiwifruit peel ethanol extracts and their solvent fractions, and the possible underlying mechanisms. Oral GRPE and GOPE administration (125-1000mg/kg) produced a dose-dependent decrease in sleep latency and an increase in sleep duration in pentobarbital-treated mice. Among three different solvent fractions of GRPE and GOPE, ethyl acetate (EA) fractions had the greatest effect on sleep duration at 250mg/kg. The total flavonoid contents of solvent fractions were proportional to sleep duration. Like diazepam (a GABA(A)-benzodiazepine (BZD) receptor agonist), the hypnotic effects of GRPE, GOPE, and their EA fractions were fully inhibited by flumazenil (a GABA(A)-BZD receptor antagonist). These results suggest that potentiation effects of GRPE and GOPE on pentobarbital-induced sleep in mice may be modulated by a GABAergic mechanism.

Formation of interfacial milk protein complexation to stabilize oil-in-water emulsions against calcium.

Oil-in-water emulsions (30% soya oil) stabilized by sodium caseinate or whey protein were destabilized in the presence of calcium, whereas lactoferrin-stabilized emulsion was stable under same conditions. At pH7, addition of lactoferrin to the caseinate or whey protein-stabilized emulsions led to association of lactoferrin with adsorbed proteins by electrostatic interactions, hence resulted in the formation of lactoferrin-caseins/whey protein interfacial complexes at the interface of the emulsion droplets. The stability of the interfacial complexes-coated emulsion droplets in the presence of Ca(2+) was examined by determination of particle size, zeta-potential and microstructure as a function of Ca(2+) concentration and added lactoferrin concentration. For emulsions made with 1% w/w caseinate or WPI, the stability of emulsions in the presence of 20 mM CaCl(2) has been improved markedly after addition of 0.2% w/w lactoferrin, suggesting the small amount of lactoferrin on the interface can largely enhance the calcium stability of milk proteins-coated emulsion droplets. Steric repulsion between the interfaces of droplets produced by the large lactoferrin molecules on the interface was considered to contribute the preventing the flocculation caused by Ca(2+) binding and reduction in the electrostatic repulsion between the emulsion droplets.

Behavior of almond oil bodies during in vitro gastric and intestinal digestion.

An aqueous suspension of almond oil bodies (about 10% lipids) was prepared and subjected to in vitro gastric (with pepsin) and intestinal (with bile salts and pancreatin) digestion, simulating fasting conditions. The physicochemical and structural changes of the almond oil body emulsion were examined. The almond oil body emulsion behaved similarly to a protein-stabilized emulsion, with flocculation of the oil bodies occurring under gastric conditions. Proteins, peptides, and phospholipids covered the surface of the oil bodies throughout gastric digestion. Under intestinal conditions, bile salts displaced the interfacial peptides and phospholipids, and disrupted the flocs. Gastric pepsinolysis of almond proteins was a prerequisite for their digestion in the duodenum. The oil body membrane had a negative impact on the efficiency of gastric digestion, and long chain fatty acids, the main lipolytic products, accumulated at the surface of the oil bodies and therefore limited the activity of pancreatic lipase.

Challenges for the delivery of long-chain n-3 fatty acids in functional foods.

Extensive research has shown that increased consumption of long-chain omega-3 polyunsaturated fatty acids (n-3 LCPUFAs), namely α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), may lower the risk of chronic diseases, such as heart disease, cancer, and arthritis. Given that Western diets are deficient in n-3 LCPUFAs, enrichment of food products is seen as an alternative for increasing the intake of these fatty acids. However, because of the high instability of these fatty acids to oxidative deterioration, enrichment of foods with n-3 LCPUFAs has been technically challenging. This review provides an overview of different technical approaches that have been taken to overcome oxidation-related problems. This review also looks at the challenges faced by health organizations, food manufacturers, and food scientists for the delivery of long-chain n-3 fatty acids in functional foods.