Toward a science-based classification of processed foods to support meaningful research and effective health policies.

Processed foods have been part of the American diet for decades, with key roles in providing a safe, available, affordable, and nutritious food supply. The USDA Food Guides beginning in 1916 and the US Dietary Guidelines for Americans (DGA) since 1980 have included various types of commonly consumed processed foods (e.g., heated, fermented, dried) as part of their recommendations. However, there are multiple classification systems based on "level" of food processing, and additional evidence is needed to establish the specific properties of foods classified as "highly" or "ultra"-processed (HPF/UPFs). Importantly, many foods are captured under HPF/UPF definitions, ranging from ready-to-eat fortified whole grain breakfast cereals to sugar-sweetened beverages and baked goods. The consequences of implementing dietary guidance to limit all intake of foods currently classified as HPF/UPF may require additional scrutiny to evaluate the impact on consumers' ability to meet daily nutrient recommendations and to access affordable food, and ultimately, on health outcomes. Based on a meeting held by the Institute for the Advancement of Food and Nutrition Sciences in May 2023, this paper provides perspectives on the broad array of foods classified as HPF/UPFs based on processing and formulation, including contributions to nutrient intake and dietary patterns, food acceptability, and cost. Characteristics of foods classified as UPF/HPFs are considered, including the roles and safety approval of food additives and the effect of food processing on the food matrix. Finally, this paper identifies information gaps and research needs to better understand how the processing of food affects nutrition and health outcomes.

Acid-hydrolyzed phenolic extract of parsley (Petroselinum crispum L.) leaves inhibits lipid oxidation in soybean oil-in-water emulsions.

The antioxidant activity of the natural phenolic extracts is limited in particular food systems due to the existence of phenolic compounds in glycoside form. Acid hydrolysis post-treatment could be a tool to convert the glycosidic polyphenols in the extracts to aglycones. Therefore, this research investigated the effects of an acid hydrolysis post-treatment on the composition and antioxidant activity of parsley extracts obtained by an ultrasound-assisted extraction method to delay lipid oxidation in a real food system (i.e., soybean oil-in-water emulsion). Acid hydrolysis conditions were varied to maximize total phenolic content (TPC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. When extracts were exposed to 0.6 M HCl for 2 h at 80 ℃, TPC was 716.92 ± 24.43 µmol gallic acid equivalent (GAE)/L, and DPPH radical scavenging activity was 66.89 ± 1.63 %. Not only did acid hydrolysis increase the concentrations of individual polyphenols, but it also resulted in the release of new phenolics such as myricetin and gallic acid. The extract's metal chelating and ferric-reducing activity increased significantly after acid hydrolysis. In soybean oil-in-water emulsion containing a TPC of 400 µmol GAE/L, the acid-hydrolyzed extract had an 11-day lag phase for headspace hexanal compared to the 6-day lag phase of unhydrolyzed extract. The findings indicated that the conversion of glycosidic polyphenols to aglycones in phenolic extracts can help extend the shelf-life of emulsion-based foods.

Implementation of plant extracts for cheddar-type cheese production in conjunction with FTIR and Raman spectroscopy comparison.

Plant extracts have demonstrated the ability to act as coagulants for milk coagulation at an adequate concentration, wide temperatures and pH ranges. This research is focused on the use of different vegetative extracts such as Citrus aurnatium flower extract (CAFE), bromelain, fig latex, and melon extract as economical and beneficial coagulants in the development of plant-based cheddar-type cheese. The cheddar-type cheese samples were subjected to physicochemical analysis in comparison to controlled cheese samples made from acetic acid and rennet. The fat, moisture, protein, and salt contents remained the same over the storage period, but a slight decline was observed in pH. The Ferric reducing antioxidant power (FRAP) increased with the passage of the ripening period. The FTIR and Raman spectra showed exponential changes and qualitative estimates in the binding and vibrational structure of lipids and protein in plant-based cheeses. The higher FTIR and Raman spectra bands were observed in acid, rennet, bromelain, and CAFE due to their firm and strong texture of cheese while lower spectra were observed in cheese made from melon extract due to weak curdling and textural properties. These plant extracts are economical and easily available alternative sources for cheese production with higher protein and nutritional contents.

Stabilization of myoglobin from different species (produced by cellular agriculture) using food-grade natural and synthetic antioxidants.

Cellular agriculture products, like myoglobin, are increasingly used by the food industry to provide desirable sensory properties to plant-based meat substitutes. This study elucidated the physicochemical properties and redox stability of myoglobin from both natural (equine) and cellular agriculture (bovine, sperm whale, and leopard) sources. The electrical characteristics and water-solubility of the different myoglobin samples were measured from pH 2.5 to 8.5. The isoelectric point of the myoglobin samples depended on the species, being pH 5.5 for equine, pH 4.5 for leopard and bovine, and pH 6.5 for sperm whale. All myoglobin samples had a solubility greater than 80% across the entire pH range studied. All myoglobin solutions appeared red and had two peaks in their UV-visible absorbance spectra after one day, which is consistent with oxymyoglobin formation. Equine myoglobin at pH 8 was selected to study its redox and color stability over time, where the oxymyoglobin oxidative status closely paralleled with the redness of the solutions. The effects of antioxidants (ascorbic acid, caffeic acid, catechin, gallic acid, quercetin, taxifolin, Trolox, and 4-methylcatechol) on the redox and color stability (redness) of the equine myoglobin (pH 8.0) was also studied. Antioxidants with low reduction potential values (ascorbic acid and quercetin) were particularly effective at enhancing the color stability of oxymyoglobin. The computational modeling study showed that amino acids on the myoglobin interacted with antioxidants through hydrogen bonds. The insights obtained may have important implications for the use of cellular agriculture to produce myoglobin for food applications.

Mathematical Modeling of Alpha-Tocopherol Early Degradation Kinetics to Predict the Shelf-Life of Bulk Oils.

The kinetics of lipid oxidation includes a lag phase followed by an exponential increase in oxidation products, which cause rancidity. Current models focus on the slope of this exponential curve for shelf-life estimation, which still requires the measurement of full oxidation kinetics. In this paper, we analyzed the formation of lipid oxidation products in stripped soybean oil containing different levels of α-tocopherol. The lag phases of lipid hydroperoxides and headspace hexanal formation were found to have a strong positive correlation with the α-tocopherol depletion time. We propose that the kinetics of antioxidant (α-tocopherol) depletion occur during the lag phase and could serve as an early shelf-life indicator. Our results showed that α-tocopherol degradation can be described by Weibull kinetics over a wide range of initial concentrations. Furthermore, we conducted in silico investigations using Monte Carlo simulations to critically evaluate the feasibility and sensitivity of the shelf-life prediction using early antioxidant degradation kinetics. Our results revealed that the shelf life of soybean oil may be accurately predicted as early as 20% of the overall shelf life. This innovative approach provides a more efficient and faster assessment of shelf life, ultimately reducing waste and enhancing product quality.

CYP eicosanoid pathway mediates colon cancer-promoting effects of dietary linoleic acid.

Human and animal studies support that consuming a high level of linoleic acid (LA, 18:2ω-6), an essential fatty acid and key component of the human diet, increases the risk of colon cancer. However, results from human studies have been inconsistent, making it challenging to establish dietary recommendations for optimal LA intake. Given the importance of LA in the human diet, it is crucial to better understand the molecular mechanisms underlying its potential colon cancer-promoting effects. Using LC-MS/MS-based targeted lipidomics, we find that the cytochrome P450 (CYP) monooxygenase pathway is a major pathway for LA metabolism in vivo. Furthermore, CYP monooxygenase is required for the colon cancer-promoting effects of LA, since the LA-rich diet fails to exacerbate colon cancer in CYP monooxygenase-deficient mice. Finally, CYP monooxygenase mediates the pro-cancer effects of LA by converting LA to epoxy octadecenoic acids (EpOMEs), which have potent effects on promoting colon tumorigenesis via gut microbiota-dependent mechanisms. Overall, these results support that CYP monooxygenase-mediated conversion of LA to EpOMEs plays a crucial role in the health effects of LA, establishing a unique mechanistic link between dietary fatty acid intake and cancer risk. These results could help in developing more effective dietary guidelines for optimal LA intake and identifying subpopulations that may be especially vulnerable to LA's negative effects.

Synergistic Mechanisms of Interactions between Myricetin or Taxifolin with α-Tocopherol in Oil-in-Water Emulsions.

The antioxidant interactions between α-tocopherol and myricetin in stripped soybean oil-in-water emulsions at pH 4.0 and pH 7.0 were analyzed. At pH 7.0, α-tocopherol (α-TOC):myricetin (MYR) ratios of 2:1 and 1:1 yielded interaction indices of 3.00 and 3.63 for lipid hydroperoxides and 2.44 and 3.00 for hexanal formation, indicating synergism. Myricetin's ability to regenerate oxidized α-tocopherol and slow its degradation was identified as the synergism mechanism. Antagonism was observed at pH 4.0 due to high ferric-reducing activity of myricetin in acidic environment. The interaction between α-tocopherol and taxifolin (TAX) was also investigated due to structural similarities of myricetin and taxifolin. α-Tocopherol and taxifolin combinations exhibited antagonism at both pH 4.0 and pH 7.0. This was associated with taxifolin's inability to recycle α-tocopherol while still increasing the prooxidant activity of iron. The combination of α-tocopherol and myricetin was found to be an excellent antioxidant strategy for oil-in-water emulsions at pH values near neutrality.

Adverse effects of titanium dioxide nanoparticles on beneficial gut bacteria and host health based on untargeted metabolomics analysis.

Titanium dioxide (TiO2) is a common additive in foods, medicines, and personal care products. In recent years, nano-scale particles in TiO2 additives have been an increasing concern due to their potential adverse effects on human health, especially gut health. The objective of this study was to determine the impact of titanium dioxide nanoparticles (TiO2 NPs, 30 nm) on beneficial gut bacteria and host response from a metabolomics perspective. In the in vitro study, four bacterial strains, including Lactobacillus reuteri, Lactobacillus gasseri, Bifidobacterium animalis, and Bifidobacterium longum were subjected to the treatment of TiO2 NPs. The growth kinetics, cell viability, cell membrane permeability, and metabolomics response were determined. TiO2 NPs at the concentration of 200 µg/mL showed inhibitory effects on the growth of all four strains. The confocal microscope results indicated that the growth inhibitory effects could be associated with cell membrane damage caused by TiO2 NPs to the bacterial strains. Metabolomics analysis showed that TiO2 NPs caused alterations in multiple metabolic pathways of gut bacteria, such as tryptophan and arginine metabolism, which were demonstrated to play crucial roles in regulating gut and host health. In the in vivo study, mice were fed with TiO2 NPs (0.1 wt% in diet) for 8 weeks. Mouse urine was collected for metabolomics analysis and the tryptophan metabolism pathway was also significantly affected in TiO2 NPs-fed mice. Moreover, four neuroprotective metabolites were significantly reduced in both in vitro bacteria and in vivo urine samples. Overall, this study provides insights into the potential adverse effects of TiO2 NPs on gut bacteria and the metabolic responses of both bacteria and host. Further research is needed to understand the causality between gut bacteria composition and the metabolism pathway, which is critical to monitor the gut-microbiome mediated metabolome changes in toxicological assessment of food components.

Impact of processing on the oxidative stability of oil bodies.

Plant lipids are stored as emulsified lipid droplets also called lipid bodies, spherosomes, oleosomes or oil bodies. Oil bodies are found in many seeds such as cereals, legumes, or in microorganisms such as microalgae, bacteria or yeast. Oil Bodies are unique subcellular organelles with sizes ranging from 0.2 to 2.5 µm and are made of a triacylglycerols hydrophobic core that is surrounded by a unique monolayer membrane made of phospholipids and anchored proteins. Due to their unique properties, in particular their resistance to coalescence and aggregation, oil bodies have an interest in food formulations as they can constitute natural emulsified systems that does not need the addition of external emulsifier. This manuscript focuses on how extraction processes and other factors impact the oxidative stability of isolated oil bodies. The potential role of oil bodies in the oxidative stability of intact foods is also discussed. In particular, we discuss how constitutive components of oil bodies membranes are associated in a strong network that may have an antioxidant effect either by physical phenomenon or by chemical reactivities. Moreover, the importance of the selected process to extract oil bodies is discussed in terms of oxidative stability of the recovered oil bodies.

Microalgal bioactive metabolites as promising implements in nutraceuticals and pharmaceuticals: inspiring therapy for health benefits.

The rapid increase in global population and shrinkage of agricultural land necessitates the use of cost-effective renewable sources as alternative to excessive resource-demanding agricultural crops. Microalgae seem to be a potential substitute as it rapidly produces large biomass that can serve as a good source of various functional ingredients that are not produced/synthesized inside the human body and high-value nonessential bioactive compounds. Microalgae-derived bioactive metabolites possess various bioactivities including antioxidant, anti-inflammatory, antimicrobial, anti-carcinogenic, anti-hypertensive, anti-lipidemic, and anti-diabetic activities, thereof rapidly elevating their demand as interesting option in pharmaceuticals, nutraceuticals and functional foods industries for developing new products. However, their utilization in these sectors has been limited. This demands more research to explore the functionality of microalgae derived functional ingredients. Therefore, in this review, we intended to furnish up-to-date knowledge on prospects of bioactive metabolites from microalgae, their bioactivities related to health, the process of microalgae cultivation and harvesting, extraction and purification of bioactive metabolites, role as dietary supplements or functional food, their commercial applications in nutritional and pharmaceutical industries and the challenges in this area of research.

Lipid oxidation in emulsions and bulk oils: a review of the importance of micelles.

Lipid oxidation is a major cause of quality deterioration in food products. In these foods, lipids are often present in a bulk or in emulsified forms. In both systems, the rate, extent and pathway of oxidation are highly dependent on the presence of colloidal structures and interfaces because these are the locations where oxidation normally occurs. In bulk oils, reverse micelles (association colloids) are present and are believed to play a crucial role on lipid oxidation. Conversely, in emulsions, surfactant micelles are present that also play a major role in lipid oxidation pathways. After a brief description of lipid oxidation and antioxidants mechanisms, this review discusses the current understanding of the influence of micellar structures on lipid oxidation. In particular, is discussed the major impact of the presence of micelles in emulsions, or reverse micelles (association colloids) in bulk oil on the oxidative stability of both systems. Indeed, both micelles in emulsions and associate colloids in bulk oils are discussed in this review as nanoscale structures that can serve as reservoirs of antioxidants and pro-oxidants and are involved in their transport within the concerned system. Their role as nanoreactors where lipid oxidation reactions occur is also commented.

Role of Solid Fat Content in Oxidative Stability of Low-Moisture Cracker Systems.

Lipid oxidation is a major pathway for the chemical deterioration of low-moisture foods. Little is known about how the physical properties of the fat used in crackers impact lipid oxidation kinetics. Fully hydrogenated soybean fat + interesterified soybean oil, fully hydrogenated soybean fat + sunflower oil, fully hydrogenated soybean oil, and soybean oil and interesterified fat alone were formulated to have varying solid fat content (SFC) at 55 °C but the same linoleic acid and tocopherol contents, so the fats had similar susceptibility to oxidation. A fluorescence probe showed that lipid mobility increased with decreasing SFC in both cracker doughs and fat blends, suggesting the probe could be used to monitor SFC directly in foods. Decreasing SFC decreased oxidation in crackers. Crackers made from interesterified fat (13.7% SFC) were more oxidatively stable (hexanal lag phase = 33 days) than crackers made from fat blends (hexanal lag phase = 24 days). These results suggest that blended fats result in regions of liquid oil high in unsaturated fatty acids within a food product prone to oxidation. Conversely, interesterified fats where unsaturated and saturated fatty acids are more evenly distributed on the triacylglycerols are more stable. Thus, interesterified fats could allow for the formulation of products higher in unsaturated fatty acids to improve nutritional profiles without sacrificing shelf life.

Making Healthy, Sustainable Diets Accessible and Achievable: A New Framework for Assessing the Nutrition, Environmental, and Equity Impacts of Packaged Foods.

There is a growing global consensus among food system experts that diets and how we source our foods must change. The sustainable nutrition community continues exploring the environmental impact and dietary value of foods. Packaged foods have been largely ignored within the dialogue, and if they are addressed, existing frameworks tend to label them all as "ultraprocessed" and uniformly discourage their consumption. This approach lacks the nuance needed to holistically evaluate packaged foods within recommended dietary patterns. Additionally, there is considerable diversity of opinion within the literature on these topics, especially on how best to improve nutrition security in populations most at risk of diet-related chronic disease. In support of addressing these challenges, 8 sustainability and nutrition experts were convened by Clif Bar & Company for a facilitated discussion on the urgent need to drive adoption of healthy, sustainable diets; the crucial role that certain packaged foods can play in helping make such diets achievable and accessible; and the need for actionable guidance around how to recommend and choose packaged foods that consider human, societal, and planetary health. This article summarizes the meeting discussion, which informed the development of a proposed framework based on guiding principles for defining sustainable, nutritious packaged foods across key nutrition, environmental, economic, and sociocultural well-being indicators. Although additional research is needed to substantiate specific metrics in order to operationalize the framework, it is intended to be a foundation from which to build and refine as science and measurement capabilities advance, and an important step toward broader adoption of healthy, sustainable diets.

Enzymatic Modification of Lecithin for Improved Antioxidant Activity in Combination with Tocopherol in Emulsions and Bulk Oil.

Oxidized α-tocopherol can be regenerated by phosphatidylethanolamine (PE), but current commercial sources of PE are too expensive for use as a food additive. The present study aims to determine the optimal reaction conditions for generating high PE lecithin (MHPEL) enzymatically and to validate the MHPEL's synergism with tocopherol in delaying lipid oxidation in an oil-in-water emulsion system at pH 7 and 4 and in bulk oil. Under optimal conditions of pH 9.0, 37 °C and 4 h, a MHPEL with ∼71.6% PE was obtained from 96% phosphatidylcholine lecithin using phospholipase D from Streptomyces chromofuscus. Mixed tocopherols (300 µmol/kg oil) and MHPEL (1500 µmol/kg oil) synergistically increased both the hydroperoxide and hexanal lag phase of lipid oxidation in stripped soybean oil-in-water emulsions at pH 7 by 3 days. At pH 4, this combination increased the hydroperoxide and hexanal lag phases by 3 and 2 days, respectively. The combination of 50 µmol/kg oil α-tocopherol and 1000 µmol/kg oil MHPEL also synergistically increased the hydroperoxide (5 days) and hexanal (4 days) lag phases in stripped bulk soybean oil. This approach represents a potential clean-label antioxidant system that could have commercial applications to decrease food waste.

Model systems for studying lipid oxidation associated with muscle foods: Methods, challenges, and prospects.

Lipid oxidation is a complex process in muscle-based foods (red meat, poultry and fish) causing severe quality deterioration, e.g., off-odors, discoloration, texture defects and nutritional loss. The complexity of muscle tissue -both composition and structure- poses as a formidable challenge in directly clarifying the mechanisms of lipid oxidation in muscle-based foods. Therefore, different in vitro model systems simulating different aspects of muscle have been used to study the pathways of lipid oxidation. In this review, we discuss the principle, preparation, implementation as well as advantages and disadvantages of seven commonly-studied model systems that mimic either compositional or structural aspects of actual meat: emulsions, fatty acid micelles, liposomes, microsomes, erythrocytes, washed muscle mince, and muscle homogenates. Furthermore, we evaluate the prospects of stem cells, tissue cultures and three-dimensional printing for future model system development. Based on this reviewing of oxidation models, tailoring correct model to different study aims could be facilitated, and readers are becoming acquainted with advantages and shortcomings. In addition, insight into recent technology developments, e.g., stem cell- and tissue-cultures as well as three-dimensional printing could provide new opportunities to overcome the current bottlenecks of lipid oxidation studies in muscle.

The Importance of Food Processing and Eating Behavior in Promoting Healthy and Sustainable Diets.

Numerous association studies and findings from a controlled feeding trial have led to the suggestion that "processed" foods are bad for health. Processing technologies and food formulation are essential for food preservation and provide access to safe, nutritious, affordable, appealing and sustainable foods for millions globally. However, food processing at any level can also cause negative health consequences that result from thermal destruction of vitamins; formation of toxins such as acrylamide; or excessive intakes of salt, sugar, and fat. Research on ultraprocessed foods centers on food composition and formulation. In addition, many modern food formulations can have poor nutritional quality and higher energy density. We outline the role of processing in the provision of a safe and secure food supply and explore the characteristics of processed foods that promote greater energy intake. Despite the potential for negative health effects, food processing and formulation represent an opportunity to apply the latest developments in technology and ingredient innovation to improve the food supply by creating foods that decrease the risk of overeating.

Production of a High-Phosphatidylserine Lecithin That Synergistically Inhibits Lipid Oxidation with α-Tocopherol in Oil-in-Water Emulsions.

Phosphatidylserine (PS) was shown to work synergistically with tocopherols to extend the shelf life of oil-in-water emulsions. However, the high cost of PS prevents it from being used as a food additive. This work investigated the potential use of a high-PS enzyme-modified lecithin to be used along with α-tocopherol to extend the lag phase of oil-in-water emulsions stabilized using Tween 20. Phospholipase D from Streptomyces sp. and L-serine were used to modify lecithin to increase the PS concentration. Enzyme activity was optimized as a function of pH and temperature using high-phosphatidylcholine (PC) soybean, sunflower, or egg lecithins. Under optimal conditions, the final PS concentrations were 92.0 ± 0.01%, 88.0 ± 0.01%, and 63.0 ± 0.02% for high-PC soybean, sunflower, and egg lecithins, respectively. α-Tocopherol (3.0 µmol/kg emulsion) alone increased the lag phase of hydroperoxide and hexanal lag phases by 3 and 4 days compared to the control. Phospholipase-D-modified high-PS soy lecithin increased hydroperoxide and hexanal lag phases by 3 and 4 days, respectively. The addition of phospholipase-D-modified high-PS sunflower and egg lecithin did not have any considerable effects on lag phases compared to the control. The combination of phospholipase-D-modified high-PS lecithins (15.0 µmol/kg emulsion) and α-tocopherol (3.0 µmol/kg emulsion) increased the antioxidant activity of α-tocopherol, increasing the hydroperoxide and hexanal lag phase by 6 and 9 days for soy, 5 and 7 days for sunflower, and 4 and 6 days for egg lecithin, respectively. All phospholipase-D-modified high-PS lecithin−tocopherol combinations resulted in synergistic antioxidant activity (interaction index > 1.0), except for α-tocopherol and high-PS egg lecithin, which showed an additive effect. This research showed that the combination of enzyme-modified high-PS lecithin and α-tocopherol could be an effective and commercially viable clean label antioxidant strategy to control lipid oxidation in emulsions.

The impact of konjac glucomannan on the physical and chemical stability of walnut oil-in-water emulsions coated by whey proteins.

BACKGROUND: Walnut oil, which is rich in polyunsaturated fatty acids (PUFAs), can be incorporated into food emulsions to increase their nutritional value. However, these emulsions are highly susceptible to deterioration during storage due to lipid oxidation. Konjac glucomannan (KGM) is a neutral plant polysaccharide used as a stabilizer, thickener or gelling agent in foods. The goal of this study was to incorporate KGM into oil-in-water emulsions containing walnut oil droplets coated by whey protein isolate (WPI) and then determine its effects on their physical and oxidative stability. RESULTS: At pH 3, inclusion of KGM (0.1-1 g kg-1 ) reduced the positive surface potential on the droplets in the emulsions and modified the secondary structure of the adsorbed whey proteins, suggesting an interaction between KGM and WPI at the droplet surfaces. The physical stability of the emulsions was enhanced when 0.1-0.6 g kg-1 KGM was added but reduced at higher levels. Lipid oxidation was inhibited in the emulsions in a dose-dependent manner when 0.2-0.6 g kg-1 KGM was added but protein oxidation was promoted at higher KGM levels. The steric hindrance provided by the thick WPI-KGM interfaces, as well as the ability of the polysaccharides to modify the antioxidant properties of the adsorbed proteins, may account for these effects. CONCLUSION: These results suggest that KGM can be used to inhibit lipid oxidation in emulsified foods containing protein-coated oil droplets. However, its level must be optimized because higher doses can result in droplet aggregation and protein oxidation. © 2022 Society of Chemical Industry.

Characterization of encapsulated γ-oryzanol powder by spray drying using whey protein and maltodextrin as wall materials.

Characterizations of encapsulated γ-oryzanol powder (EOP) using whey protein concentrate (WPC) and maltodextrin as wall materials were studied. Rice bran oil (RBO) with 2% γ-oryzanol was encapsulated using different concentrations of WPC (0.2-1.0%) combined with 10% of maltodextrin before spray drying. The physicochemical characteristics and reconstitution of EOP were investigated. The results found that different concentrations of WPC affected EOP characteristics. The EOP coated 1% WPC exhibited low moisture content and water activity (aw) containing high γ-oryzanol content and encapsulation efficiency. Morphology of EOP using SEM displayed spheroid shape with smooth and crack-free surface. However, EOP emulsion had relatively larger particle size and lower solubility index than the fresh emulsion after reconstitution, but a good creaming stability of reconstituted EOP was observed. Therefore, it can be concluded that using 1% WPC combined with 10% maltodextrin provided good performance of encapsulated RBO with 2% γ-oryzanol using spray drying. According to physicochemical characteristics, the EOP has good potential as a food ingredient for food industry and as an excipient for pharmaceutical and cosmetic industries.

Antioxidant and prooxidant activities of tea polyphenols in oil-in-water emulsions depend on the level used and the location of proteins.

We studied the impacts of protein location (interface or aqueous phase) on the antioxidant and prooxidant activities of tea polyphenols (TP) in model oil-in-water emulsions (pH 7) at a low (0.01% w/v) or high (0.04 % w/v) concentration. TP at 0.01% reduced the levels of both lipid and protein oxidation markers in emulsions, independent of the protein location. However, TP were more potent when proteins were located at the interface. At 0.04%, TP were only weakly antioxidant towards lipids but were prooxidant towards proteins in emulsions with proteins at the interface, whereas they were still somewhat antioxidant for aqueous phase proteins. These results indicate that TP may act as either antioxidants or prooxidants depending on their concentration and also on the location of the proteins in emulsions. The level of TP should be optimized for emulsion-based foods or beverages to achieve optimum antioxidant activity.