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.

Formation of Antioxidant Multilayered Coatings for the Prevention of Lipid and Protein Oxidation in Oil-in-Water Emulsions: Lycium barbarum Polysaccharides and Whey Proteins.

The impact of Lycium barbarum polysaccharides (LBPs) on the physical and chemical stability of oil-in-water emulsions coated by a whey protein isolate (WPI) was investigated. At pH 3.0, the anionic LBP (0.2-0.6 wt %) molecules were electrostatically deposited onto the cationic surfaces of the WPI-coated oil droplets, leading to the formation of stable multilayered emulsions containing WPI-/LBP-coated oil droplets. However, increasing the LBP concentration to 0.8 wt % led to oil droplet aggregation, which was attributed to charge neutralization, bridging flocculation, and/or depletion flocculation. For subsequent experiments, a low (0.2%) and an intermediate (0.6%) LBP dose was used to prepare the secondary emulsions, and then their physical and oxidative stability was studied during 8 days of storage at 37 °C. The presence of the multilayer WPI/LBP coatings around the oil droplets inhibited lipid oxidation (reduced levels of lipid hydroperoxides and 2-thiobarbituric acid-reactive substances), as well as protein oxidation (reduced levels of carbonyl formation, sulfhydryl consumption, molecular weight modifications, intrinsic fluorescence loss, and Schiff-base fluorescence gain). The antioxidant effects of the multilayer coatings were greater at the higher LBP concentration. These results suggest that LBP, a natural plant-based polysaccharide isolated from a traditional Chinese medicine, can be used to improve the quality of emulsion-based foods. However, the level used should be optimized to ensure good physical and oxidative stability of the emulsions.

Impact of tea polyphenols on the stability of oil-in-water emulsions coated by whey proteins.

The ability of tea polyphenols (0, 0.01, 0.02 or 0.04 w/v %) to inhibit lipid and protein oxidation in walnut oil-in-water (O/W) emulsions was examined, as well as to alter their stability to aggregation and creaming. The lipid droplets in these emulsions were coated by whey proteins. The physical stability of the emulsions during storage (50 °C, 96 h) was improved by addition of 0.01% tea polyphenols, but reduced when higher levels were added. Low levels (0.01%) of tea polyphenols inhibited lipid oxidation (lipid hydroperoxide and 2-thiobarbituric acid-reactive substance formation) and protein oxidation (carbonyl and Schiff base formation, sulfhydryl and intrinsic fluorescence loss, and molecular weight changes). However, high levels (0.04%) of tea polyphenols were less effective at inhibiting lipid oxidation, and actually promoted protein oxidation. Tea polyphenols are natural antioxidants that can enhance the quality and shelf life of emulsified polyunsaturated lipids when used at an appropriate concentration.

Inhibition of Lipid and Protein Oxidation in Whey-Protein-Stabilized Emulsions Using a Natural Antioxidant: Black Rice Anthocyanins.

The food industry is exploring the natural environment to identify botanical extracts that can be used as functional ingredients that can replace synthetic ingredients in foods. In the present study, the ability of black rice anthocyanins as natural antioxidants to inhibit both lipid and protein oxidation in protein-stabilized oil-in-water emulsions was examined. Whey-protein-stabilized emulsions were prepared containing 0, 0.02, 0.04, and 0.06% (w/v) anthocyanins, and then the impact of this plant-based extract on their physical and chemical stabilities was evaluated. The addition of the anthocyanins improved the physical stability of the emulsions in a dose-dependent manner by inhibiting droplet aggregation during storage (35 °C for 5 days). The anthocyanins also exhibited good antioxidant activity in a dose-dependent manner, as seen by their capacity for inhibiting both lipid oxidation (reduced lipid hydroperoxides and malondialdehyde) and protein oxidation (reduced carbonyl and Schiff base formation, intrinsic fluorescence loss, and molecular weight changes). Black rice anthocyanins may therefore be an effective botanical extract for improving the stability of protein-stabilized food emulsions by inhibiting oxidative reactions.

A combination of monoacylglycerol crystalline network and hydrophilic antioxidants synergistically enhances the oxidative stability of gelled algae oil.

In this study, base algae oil was gelled through the formation of a crystal network using food-grade monoacylglycerol (MAG). The impact of the MAG concentration (5, 10, 20 wt%) and water content (0, 5 wt%) on the physical properties and oxidative stability of the gelled algae oil was systematically investigated. The antioxidative activity of 300 µM hydrophilic antioxidant, i.e., ascorbic acid and green tea extract, on the oxidative stability of the gelled algae oil by 20 wt% of MAG was also examined. The results obtained clearly showed that the melting temperature, melting of entropy, and complex modulus of the algae oil increased with increasing the MAG concentration. The addition of 5 wt% water could negatively affect the strength of the MAG crystal network, while a physically stable gel system could only be formed with 20 wt% MAG. The stronger crystal network formed by 20 wt% MAG retarded the lipid oxidation of algae oil due to the creation of a physical barrier to restrain the attack from oxygen. The addition of green tea extract could further synergize with the MAG crystalline network by forming a thermodynamic barrier to effectively quench the radicals, thus prolonging the oxidative stability of algae oil 4-fold longer than that of the base algae oil.

Ultrasound improving the physical stability of oil-in-water emulsions stabilized by almond proteins.

BACKGROUND: Vegetable proteins are increasingly used to stabilize oil-in-water (O/W) emulsions. However, emulsions are thermodynamically unstable. Recently, high-intensity ultrasound (US) has been used to enhance the stability of emulsions. For these reasons, and considering almond (Prunus dulcis L.) as a good source of high-quality proteins, the aim of this work was to investigate the effect of US treatment on the stability of pre-emulsification O/W emulsions coated with almond protein isolate (API). RESULTS: The influence of API concentration (0.25-2.0 g L-1 ), ion strength (0-500 mmol L-1 NaCl), and pH (3.0-7.0) on the stability of US-treated emulsions was evaluated. US treatment (200-600 W, 25 kHz, 15 min) led to a significant reduction in the particles size of droplets in emulsions, increased critical osmotic pressure and additional protein interfacial adsorption, and thus the formation of more stable emulsions. The more unfolded and random coil structures of the proteins were detected at higher US power, facilitating protein interfacial adsorption. Increasing API concentrations resulted in higher stability of US-treated emulsions against untreated counterparts. The US-treated emulsions were more resistant to salt than untreated samples. In the range from pH 3.0 to7.0, US treatment also enhanced the physical stability of emulsions compared with untreated emulsions. CONCLUSION: US technology could be applied to produce more stable O/W food emulsions stabilized by proteins. © 2018 Society of Chemical Industry.

Safety evaluation and lipid-lowering effects of food-grade biopolymer complexes (ε-polylysine-pectin) in mice fed a high-fat diet.

ε-Polylysine (ε-PL) is a potent cationic antimicrobial, but its application as a food additive is currently limited because it tends to precipitate with anionic species in food matrices. Previous research has shown that the formation of an electrostatic complex between cationic ε-PL and anionic pectin (P) improved the physical stability of ε-PL while maintaining its antimicrobial activity. However, the impact of complexation on the effects of ε-PL on health is currently unknown. A subchronic toxicity study was therefore carried out to determine the safety of ingested ε-PL-P complexes using high-fat diet-fed male and female mice. After a 13-week dietary treatment with P, ε-PL, or ε-PL-P complexes, no significant toxicological effects were observed on the survival, mean body weight, food consumption, and organ weights of the animals, suggesting that the complexes were safe for oral consumption. Interestingly, the ε-PL-P complexes were found to have several beneficial health effects: suppression of high-fat diet-induced elevation of serum aspartate aminotransferase and alanine aminotransferase activities, reduction in serum total triglyceride and cholesterol levels, and an increase in fecal excretion of triglycerides. These effects were much stronger in female mice than in male mice. Moreover, the lipid-lowering effects were observed only for the ε-PL-P complexes but not for ε-PL or P alone at the same doses. Overall, our results demonstrate the oral safety of ε-PL-P complexes and their gender-specific lipid-lowering effects in high-fat diet-fed mice, which provide an important basis for the utilization of ε-PL-P complexes in food systems as functional ingredients.

Physical and Oxidative Stability of Flaxseed Oil-in-Water Emulsions Fabricated from Sunflower Lecithins: Impact of Blending Lecithins with Different Phospholipid Profiles.

There is great interest in the formulation of plant-based foods enriched with nutrients that promote health, such as polyunsaturated fatty acids. This study evaluated the impact of sunflower phospholipid type on the formation and stability of flaxseed oil-in-water emulsions. Two sunflower lecithins (Sunlipon 50 and 90) with different phosphatidylcholine (PC) levels (59 and 90%, respectively) were used in varying ratios to form emulsions. Emulsion droplet size, charge, appearance, microstructure, and oxidation were measured during storage at 55 °C in the dark. The physical and chemical stability increased as the PC content of the lecithin blends decreased. The oxidative stability of emulsions formulated using Sunlipon 50 was better than emulsions formulated using synthetic surfactants (SDS or Tween 20). The results are interpreted in terms of the impact of emulsifier type on the colloidal interactions between oil droplets and on the molecular interactions between pro-oxidants and oil droplet surfaces.

Role of continuous phase protein, (-)-epigallocatechin-3-gallate and carrier oil on ß-carotene degradation in oil-in-water emulsions.

The chemical instability of ß-carotene limits its utilization as a nutraceutical ingredient in foods. In this research, the effect of continuous phase alpha-lactalbumin (α-LA) and (-)-epigallocatechin-3-gallate (EGCG) on ß-carotene degradation in medium chain triacylglycerol (MCT)- and corn oil-in-water emulsions was examined. EGCG significantly inhibited ß-carotene degradation in both MCT and corn oil-in-water emulsions in a dose dependent manner. α-LA was not able to protect ß-carotene in MCT emulsions and the combination of EGCG and α-LA had a similar effect as EGCG alone. EGCG had no effect on lipid oxidation in corn oil-in-water emulsions but can protect ß-carotene. ß-Carotene was more stable in corn oil emulsions stabilized by α-LA compared to emulsions stabilized by Tween 20. These results show that EGCG is effective at protecting ß-carotene in different emulsion systems without negatively impacting lipid oxidation suggesting that it could be utilized to increase the incorporation of ß-carotene into food emulsions.

Enhancement of carotenoid bioaccessibility from carrots using excipient emulsions: influence of particle size of digestible lipid droplets.

The influence of initial lipid droplet size on the ability of excipient emulsions to increase carotenoid bioaccessibility from carrots was investigated using a simulated gastrointestinal tract (GIT). Corn oil-in-water excipient emulsions were fabricated with different surface-weighted mean droplet diameters: d32 = 0.17 µm (fine), 0.46 µm (medium), and, 10 µm (large). Bulk oil containing a similar quantity of lipids as the emulsions was used as a control. The excipient emulsions and control were mixed with pureed carrots, and then passed through a simulated GIT (mouth, stomach, and small intestine), and changes in particle size, charge, microstructure, lipid digestion, and carotenoid bioaccessibility were measured. Carotenoid bioaccessibility significantly increased with decreasing lipid droplet size in the excipient emulsions, which was attributed to the rapid formation of mixed micelles that could solubilize the carotenoids in the intestinal fluids. These results have important implications for designing excipient foods, such as dressings, dips, creams, and sauces, to increase the bioavailability of health-promoting nutraceuticals in foods.

Impact of ε-polylysine and pectin on the potential gastrointestinal fate of emulsified lipids: In vitro mouth, stomach and small intestine model.

ε-Polylysine (ε-PL) is a broad-spectrum antimicrobial biopolymer, suitable for use in foods; however, some studies suggest that it may also inhibit lipid digestion. We therefore examined the effect of polylysine on the digestion of corn oil-in-water emulsions, using a simulated gastrointestinal tract (GIT) that included oral, gastric, and intestinal phases. Both mucin and polylysine had pronounced influences on the particle size, charge, and aggregation state throughout the GIT. However, surprisingly, we found that ε-polylysine did not have a significant impact on lipid digestion, either in the presence or absence of anionic mucin. However, it did form strong electrostatic complexes with mixed micelles, which could decrease the transport and absorption of lipids in the small intestine. These results have important implications for the incorporation of polylysine into food systems, particularly those containing lipophilic nutrients.

Enhancing Nutraceutical Bioavailability from Raw and Cooked Vegetables Using Excipient Emulsions: Influence of Lipid Type on Carotenoid Bioaccessibility from Carrots.

The influence of the nature of the lipid phase in excipient emulsions on the bioaccessibility and transformation of carotenoid from carrots was investigated using a gastrointestinal tract (GIT) model. Excipient emulsions were fabricated using whey protein as an emulsifier and medium-chain triglycerides (MCT), fish oil, or corn oil as the oil phase. Changes in particle size, charge, and microstructure were measured as the carrot-emulsion mixtures were passed through simulated mouth, stomach, and small intestine regions. Carotenoid bioaccessibility depended on the type of lipids used to form the excipient emulsions (corn oil > fish oil ≫ MCT), which was attributed to differences in the solubilization capacity of mixed micelles formed from different lipid digestion products. The transformation of carotenoids was greater for fish oil and corn oil than for MCT, which may have been due to greater oxidation or isomerization. The bioaccessibility of the carotenoids was higher from boiled than raw carrots, which was attributed to greater disruption of the plant tissue facilitating carotenoid release. In conclusion, excipient emulsions are highly effective at increasing carotenoid bioaccessibility from carrots, but lipid type must be optimized to ensure high efficacy.

Enhancing vitamin E bioaccessibility: factors impacting solubilization and hydrolysis of α-tocopherol acetate encapsulated in emulsion-based delivery systems.

Oil-soluble vitamins are often encapsulated within emulsion-based delivery systems to facilitate their incorporation into aqueous-based products. We have examined the influence of carrier oil type and simulated small intestinal fluid (SSIF) composition on the bioaccessibility of emulsified vitamin E using a gastrointestinal model. Oil-in-water emulsions containing vitamin E acetate were prepared using bile salts as emulsifier, and either long chain triacylglycerols (glyceryl trioleate, LCT) or medium chain triacylglycerols (glyceryl trioctanoate, MCT) as carrier oils. The addition of calcium (CaCl2) to the SSIF increased the extent of lipid digestion in LCT-emulsions, but had little impact in MCT-emulsions. The bioaccessibility of vitamin E increased in the presence of calcium and phospholipids (DOPC) in LCT-emulsions, but decreased in MCT-emulsions. The highest bioaccessibility (≈66%) was achieved for LCT-emulsions when the SSIF contained both calcium and phospholipids. The conversion of α-tocopherol acetate to α-tocopherol after in vitro digestion was considerably higher for LCT-emulsions when calcium ions were present in the SSIF, but was not strongly affected by SSIF composition for MCT-emulsions. In general, this research provides important information about the factors influencing the bioaccessibility of emulsified vitamin E, which could be used to design more effective emulsion-based delivery systems for increasing the oral bioavailability of this important bioactive component.

Influence of whey protein-beet pectin conjugate on the properties and digestibility of ß-carotene emulsion during in vitro digestion.

The impact of a whey protein isolate (WPI)-beet pectin (BP) conjugate (formed by dry-heating) on the physical properties and digestibilities of ß-carotene and carrier oil in oil-in-water emulsions was studied when they passed through a model gastrointestinal system. ß-Carotene emulsions were stabilized by WPI, unconjugated and conjugated WPI-BP, separately. The emulsions were then passed through an in vitro digestion model and the mean droplet size, droplet distribution, zeta-potential, free fatty acids and ß-carotene released were measured. The stability to droplet flocculation and coalescence during digestion was increased for the WPI-BP conjugate stabilized emulsion. Addition of BP onto the WPI stabilized emulsions could inhibit the releases of carrier oil (MCT) and ß-carotene. The releases of free fatty acids and ß-carotene did not differ greatly between the unconjugated and conjugated WPI-BP stabilized emulsions. These results have important implications for protein-polysaccharide stabilized emulsions and conjugates used for the protection and delivery of bioactive compounds.

Impact of diacylglycerol and monoacylglycerol on the physical and chemical properties of stripped soybean oil.

In this study, we determined the effect of diacylglycerol (DAG) and monoacylglycerol (MAG) on the oxidative stability of stripped soybean oil (SSO) and on the antioxidative effectiveness of α-tocopherol in SSO. We also examined the influence of DAG and MAG on the physical properties of SSO. DAG (0-2.5wt%) had little effect on the chemical stability of SSO and on the antioxidative activity of 40µM α-tocopherol in SSO (55°C). MAG (0-2.5wt%) had no remarkable impact on the chemical stability of SSO. The addition of MAG (0.5wt%) suppressed the effectiveness of α-tocopherol (40µM) in SSO. The addition of DAG did not cause an appreciable change in the interfacial tension (IFT) of SSO, indicating that it was not strongly surface active. MAG significantly decreased the interfacial tension of SSO, due to its strong surface active properties. Wide angle X-ray scattering (WAXS) analysis showed that DAG did not alter the structured organisation of SSO, which remained in an amorphous form, whereas MAG led to strong scattering, indicating the formation of crystals. The physical properties of DAG and MAG in the SSO may be related to the chemical stability of SSO and the effectiveness of antioxidants incorporated. These results can be used to better understand the physicochemical mechanisms by which minor components impact oxidation of bulk oils.

Nutraceutical nanoemulsions: influence of carrier oil composition (digestible versus indigestible oil) on ß-carotene bioavailability.

BACKGROUND: Carotenoids, such as ß-carotene, are widely used in foods and beverages as natural colorants and nutraceuticals. We investigated the influence of carrier oil composition (ratio of digestible to indigestible oil) on the physical stability, microstructure and bioaccessibility of ß-carotene nanoemulsions using a simulated gastrointestinal tract model. RESULTS: ß-Carotene nanoemulsions (d < 150 nm) were formed by high-pressure homogenization using sucrose monoester and lysolecithin as emulsifiers, and mixtures of corn oil (digestible) and lemon oil (indigestible) as the lipid phase. All of the nanoemulsions underwent extensive droplet aggregation under mouth, stomach and small intestine conditions. The extent of free fatty acid production in the small intestine increased as the amount of digestible oil in the droplets increased. The bioaccessibility of ß-carotene also increased with increasing digestible oil content, ranging from ∼5% for the pure lemon oil system to ∼76% for the pure corn oil system. This effect was attributed to the ability of mixed micelles formed from triglyceride digestion products (free fatty acids and monoglycerides) to solubilize ß-carotene. CONCLUSIONS: This study provides important information for developing effective delivery systems for lipophilic bioactive components in food and beverage applications.

Design of foods with bioactive lipids for improved health.

Numerous studies have found an association between the consumption of certain bioactive lipids and improved human health, e.g., the prevention, delay, or treatment of chronic and acute diseases, such as cancer, cardiovascular disease (CVD), osteoporosis, and immune disorders. In this review, we discuss food-based sources and potential beneficial attributes of major dietary bioactive lipids: polyunsaturated fatty acids; carotenoids; phytosterols and phytostanols; and fat-soluble vitamins. We summarize the various challenges associated with incorporating these bioactive lipids into foods and beverages, such as poor water solubility, high melting point, and low chemical stability. Finally, we propose several techniques that have been used to solve the challenges and integrate dietary bioactive lipids into foods for improved health.

Nanoemulsion delivery systems: influence of carrier oil on ß-carotene bioaccessibility.

Consumption of carotenoids may reduce the incidences of certain chronic diseases, but their use in foods is currently limited because of their poor water-solubility, low bioavailability and chemical instability. We examined the impact of carrier oil type on the bioaccessibility of ß-carotene encapsulated within nanoemulsion-based delivery systems. Oil-in-water nanoemulsions (d<200nm) were formed using a non-ionic surfactant (Tween 20) as emulsifier and long chain triglycerides (LCT), medium chain triglycerides (MCT) or orange oil as carrier oils. The influence of carrier oil type on ß-carotene bioaccessibility was established using an in vitro model to simulate the oral, gastric and small intestinal phases of the gastrointestinal tract. The rate and extent of free fatty acid production in the intestine decreased in the order LCT≈MCT≫orange oil; whereas ß-carotene bioaccessibility decreased in the order LCT≫MCT>orange oil. The bioaccessibility of ß-carotene was negligible (≈0%) in orange oil nanoemulsions because no mixed micelles were formed to solubilise ß-carotene, and was relatively low (≈2%) in MCT nanoemulsions because the mixed micelles formed were too small to solubilise ß-carotene. In contrast, ß-carotene bioaccessibility was relatively high (≈66%) in LCT nanoemulsions. Our results have important implications for the design of effective delivery systems for encapsulation of carotenoids and other lipophilic bioactive components.

Inhibition of Ostwald ripening in model beverage emulsions by addition of poorly water soluble triglyceride oils.

Beverage emulsions containing flavor oils that have a relatively high water-solubility are unstable to droplet growth due to Ostwald ripening. The aim of this study was to improve the stability of model beverage emulsions to this kind of droplet growth by incorporating poorly water-soluble triglyceride oils. High pressure homogenization was used to prepare a series of 5 wt% oil-in-water emulsions stabilized by modified starch that had different lipid phase compositions (orange oil : corn oil). Emulsions prepared using only orange oil as the lipid phase were highly unstable to droplet growth during storage, which was attributed to Ostwald ripening resulting from the relatively high water-solubility of orange oil. Droplet growth could be effectively inhibited by incorporating ≥ 10% corn oil into the lipid phase prior to homogenization. In addition, creaming was also retarded because the lipid phase density was closer to that of the aqueous phase density. These results illustrate a simple method of improving the physical stability of orange oil emulsions for utilization in the food, beverage, and fragrance industries.

Impact of dietary fiber coatings on behavior of protein-stabilized lipid droplets under simulated gastrointestinal conditions.

Multilayer emulsions containing lipid droplets coated by lactoferrin (LF) - anionic polysaccharide layers have improved resistance to environmental stresses (such as pH, salt, and temperature), but their behavior within the gastrointestinal tract (GIT) is currently unknown. The objective of this research was therefore to monitor changes in the physicochemical properties and digestibility of these systems under simulated GIT conditions. Primary emulsions (5% corn oil, 0.5% LF) were prepared using a high-pressure homogenizer. Secondary emulsions (5% corn oil, 0.5% LF, 0.5% polysaccharide) were prepared by incorporating alginate, low methoxyl pectin (LMP) or high methoxyl pectin (HMP) into primary emulsions. Emulsions were then subjected to simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) conditions in sequence. LF, LF-LMP and LF-HMP emulsions were stable to droplet aggregation in the stomach but aggregated in the small intestine, whereas LF-alginate emulsions aggregated in both the stomach and small intestine. The presence of a dietary fiber coating around the initial lipid droplets had little influence on the total extent of lipid digestion in SIF, but LF-alginate emulsions had a slower initial digestion rate than the other emulsions. These results suggest that the dietary fiber coatings may become detached in the small intestine, or that they were permeable to digestive enzymes. Pepsin was found to have little influence on the physical stability or digestibility of the emulsions. The knowledge obtained from this study is important for the design of delivery systems for encapsulation and release of lipophilic bioactive ingredients.