Influence of dietary fiber on in-vitro lipid digestion of emulsions prepared with high-intensity ultrasound

Conversion of α-linolenic acid into n-3 long-chain polyunsaturated fatty acids: bioavailability and dietary regulation

N-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs) are essential for physiological requirements and disease prevention throughout life but are not adequately consumed worldwide. Dietary supplementation with plant-derived α-linolenic acid (ALA) has the potential to rebalance the fatty acid profile and enhance health benefits but faces challenges such as high β-oxidation consumption, low hepatic conversion efficiency, and high oxidative susceptibility under stress. This review focuses on the metabolic fate and potential regulatory targets of ALA-containing lipids in vivo, specifically the pathway from the gastrointestinal tract to the lymph, blood circulation, and liver. We propose a hypothesis that positively regulates the conversion of ALA into n-3 LCPUFAs based on the model of "fast" or "slow" absorption, transport, and hepatic metabolic fate. Furthermore, the potential effects of dietary nutrients on the metabolic conversion of ALA into n-3 LCPUFAs are discussed. The conversion of ALA is differentially regulated by structured lipids, phospholipids, other lipids, carbohydrates, specific proteins, amino acids, polyphenols, vitamins, and minerals. Future research should focus on designing a steady-state and precise delivery system for ALA, coupled with specific nutrients or phytochemicals, to effectively improve its metabolic conversion and ultimately achieve synergistic regulation of nutrition and health effects.

Mechanism for improving the in vitro digestive properties of coconut milk by modifying the structure and properties of coconut proteins with monosodium glutamate

In this paper, the effect of monosodium glutamate (MSG) on coconut protein (CP) solubility, surface hydrophobicity, emulsification activity, ultraviolet spectroscopy and fluorescence spectroscopy was investigated. Meanwhile, the changes in the in vitro digestive properties of coconut milk were also further analyzed. MSG treatment altered the solubility and surface hydrophobicity of CP, thereby improving protein digestibility. Molecular docking showed that CP bound to pepsin and trypsin mainly through hydrogen bonds and salt bridges. And MSG increased the cleavable sites of pepsin and trypsin on CP, thus further improving the protein digestibility. In addition, MSG increased the Na+ concentration in coconut milk, promoted flocculation and aggregation between coconut milk droplets, which prevented the binding of lipase and oil droplets and inhibited lipid digestion. These findings may provide new ideas and insights to improve the digestive properties of plant-based milk.

Kernel properties related to carotenoid release during in vitro gastrointestinal digestion in commercial dent maize hybrids

The objective of study was to investigate the relationships between maize kernel properties and carotenoid release during simulated gastrointestinal digestion of 103 hybrids of dent type. Commercial maize hybrids significantly differed in kernel hardness, chemical composition and carotenoid profile. Across all hybrids, the amount of digestible individual carotenoids increased as follows: β-carotene < α-cryptoxanthin < β-cryptoxanthin < lutein < zeaxanthin. The amount of digested carotenoids correlated negatively with amylose content and amylose-to-amylopectin ratio, while it correlated positively with the content of neutral detergent fibres and amylopectin as well as the Stenvert index. However, the content of endosperm lipids could not be related to carotenoid digestibility. Findings clearly indicate that the carotenoid release from the kernel during digestion is related to specific physical and chemical properties, leading to a better understanding of the effects of kernel matrix structure on carotenoid digestibility in dent-type maize hybrids.

The lipid digestion behavior of oil-in-water emulsions stabilized by different particle-sized insoluble dietary fiber from citrus peel

In this study, oil-in-water emulsions stabilized by insoluble dietary fibre from citrus peel (CIDF) exhibited an obviously delayed lipid digestion property through gastrointestinal tract (GIT) model. Our results suggested that the rate and extent of lipid digestion greatly relied on particle sizes and concentrations of CIDF, and the inhibition effect of lipolysis was markedly enhanced with decreasing particle sizes and increasing CIDF levels. Furthermore, compared with Tween80-stabilized emulsion, the maximum inhibition extent of lipolysis was 38.77% for CIDF400-stabilized one at 0.4 wt% concentration. Effects of CIDFs on lipid digestion was mainly due to the formation of protective layers around oil droplets, further blocking the entry of lipase to the internal lipids, and/or attributed to the increasing viscosity of emulsions caused by CIDFs, finally limiting the transportation of some substances in the simulated small intestine digestion. Our research would provide useful references for the application of CIDF-stabilized emulsions in low-calorie food.

Potential of Modification of Techno-Functional Properties and Structural Characteristics of Citrus, Apple, Oat, and Pea Dietary Fiber by High-Intensity Ultrasound

Plant fibers are rich in dietary fiber and micronutrients but often exhibit poor functionality. Ultrasonication can affect the particle size of plant fiber, thereby influencing other techno-functional properties. Therefore, this study aimed to investigate the effects of high-intensity ultrasound on citrus, apple, oat, and pea fiber. Initially, solutions containing 1 wt% of plant fiber were homogenized using ultrasonication (amplitude 116 µm, t = 150 s, energy density = 225 kJ/L, P¯ = 325 W). Due to cavitation effects induced by ultrasound, differences in particle size and a shift in the ratio of insoluble and alcohol-insoluble fractions for dietary fiber were observed. Additionally, viscosities for citrus and apple fiber increased from 1.4 Pa·s to 84.4 Pa·s and from 1.34 Pa·s to 31.7 Pa·s, respectively, at shear rates of 100 1s. This was attributed to observed differences in the microstructure. Freeze-dried samples of purified citrus and apple fiber revealed thin and nearly transparent layers, possibly contributing to enhanced water binding capacity and, therefore, increased viscosity. Water binding capacity for citrus fiber increased from 18.2 g/g to 41.8 g/g, and a 40% increase was observed for apple fiber. Finally, ultrasound demonstrated itself be an effective technology for modifying the techno-functional properties of plant fiber, such as water binding capacity.

Influence of High-Intensity Ultrasound on Characteristics and Bioaccessibility of Pea Protein in Fiber-Enriched Suspensions

Pea protein is of high interest for the food industry owing to its low allergenicity and high nutritional value. However, it often exhibits poor functionality, such as low solubility. The presence of dietary fiber in food products is beneficial for human health but may decrease the bioaccessibility of nutrients. Ultrasound, as a promising green technology, may influence properties of fibers and proteins and, thus, bioaccessibility. Therefore, this study investigated the effects of high-intensity ultrasound on the characteristics and protein bioaccessibility of protein-fiber suspensions. Suspensions containing different fiber compounds (1 wt.%) and pea protein (5 wt.%) were homogenized using high-intensity ultrasound (amplitude 116 µm, t = 150 s, energy density = 225 kJ/L, P¯ = 325 W). Owing to sonication-induced cavitation, the dispersibility of the protein was enhanced, and the viscosity of solutions containing citrus or apple fiber was increased. FE-SEM revealed the formation of different fiber-protein networks during sonication. Even if viscosity is known to have an impact on the bioaccessibility of nutrients, no restrictions on the digestibility of protein were detected during an in vitro digestion. Thus, protein uptake is probably not affected, and ultrasound can be used to modify the technofunctionality of fibers and proteins without any nutritional disadvantages.

Strategies for modulating the lipid digestion of emulsions in the gastrointestinal tract

The structural changes in emulsion products can be used to control the bioavailability of fatty acids and lipophilic compounds. After ingestion, lipid droplets undergo breakdown and structural changes as they pass through the gastrointestinal tract. The oil-water interface plays a critical role in modulating the digestive behavior of lipid droplets because changes in the interfacial layer control the adsorption of lipase and bile salts and determine the overall rate and extent of lipid digestion. Therefore, lipid digestibility can be tuned by selecting the appropriate types and levels of stabilizers. The stabilizer can change the lipase accessibility and exposure of lipid substrates, resulting in variable digestion rates. However, emulsified lipids are not only added to food matrixes but are also co-ingested from other dietary components. Therefore, overall consumption behaviors can affect the digestion rate and digestibility of emulsified lipids. Although designing an emulsion structure is challenging, controlling lipid digestion can improve the health benefits of products. Therefore, a thorough understanding of the process of emulsified lipid digestion is required to develop food products that enable specific physiological responses. The targeted or delayed release of lipophilic molecules and fatty acids through emulsion systems has significant applications in healthcare and pharmaceuticals.

Technological Properties and Composition of Enzymatically Modified Cranberry Pomace

Cranberry pomace obtained after juice production is a good source of dietary fiber and other bioactive compounds. In this study, cranberry pomace was hydrolyzed with Viscozyme® L, Pectinex® Ultra Tropical, Pectinex® Yieldmash Plus, and Celluclast® 1.5L (Novozyme A/S, Denmark). The soluble and insoluble dietary fiber was determined using the Megazyme kit, while the changes in mono-, disaccharide and oligosaccharides’ contents were determined using HPLC-RI; the total phenolic contents were determined by Folin−Ciocalteu’s Assay. Prebiotic activity, using two probiotic strains Lactobacillus acidophilus DSM 20079 and Bifidobacterium animalis DSM 20105, was investigated. The technological properties, such as hydration and oil retention capacity, were evaluated. The enzymatic treatment increased the yield of short-chain soluble saccharides. The highest oligosaccharide content was obtained using Viscozyme® L and Pectinex® Ultra Tropical. All of the tested extracts of cranberry pomace showed the ability to promote growth of selected probiotic bacteria. The insoluble dietary fiber content decreased in all of the samples, while the soluble dietary fiber increased just in samples hydrolyzed with Celluclast® 1.5L. The highest content of total phenolic compounds was obtained using Viscozyme® L and Pectinex® Ultra Tropical (10.9% and 13.1% higher than control, respectively). The enzymatically treated cranberry pomace exhibited lower oil and water retention capacities in most cases. In contrast, water swelling capacity increased by 23% and 70% in samples treated with Viscozyme® L and Celluclast® 1.5L, respectively. Enzymatically treated cranberry pomace has a different composition and technological properties depending on the enzyme used for hydrolysis and can be used in various novel food products.

Role of pectin characteristics in orange juice stabilization: Effect of high-pressure processing in combination with centrifugation pretreatments

"High-pressure processing (HPP) plus" combined technologies are applied to overcome the limitation of single HPP and to produce juices with more stable quality during storage. This research explored the potential of HPP in combination with centrifugation to produce cloud stable orange juice during refrigerated storage. The results indicated that HPP combined processing technology significantly improved the cloud stability of orange juice, which was related to removed large particles, reduced viscosity, decreased protein contents, and inactivated pectin methylesterase activity induced by centrifugation (P < 0.05). Besides, chelator solubilized pectin (CSP) decreased but water solubilized pectin (WSP) maintained in the juice after centrifugation. During storage, the conversion of pectin fraction from WSP to CSP, resulting in sedimentation appeared in centrifugation treated orange juice when stored for 28 days. In general, pectin characteristics changes and pectin fractions conversion were the main driving forces affecting cloud stability of orange juice pasteurized by HPP in combination with centrifugation and during chilled storage.

Effect of high intensity ultrasound on the structure and solubility of soy protein isolate-pectin complex

In this study, a soy protein isolate (SPI)-pectin (PC) complex was prepared, and the effects of different high intensity ultrasound (HIU) powers on the structure and solubility of the complex were studied. Fourier transform infrared (FTIR) spectroscopy analysis exhibited that with increasing HIU power, the α-helix content of the SPI in the complex was significantly reduced, and the random coil content increased; however, an opposite trend appeared after higher power treatments. Fluorescence spectra showed that HIU treatment increased the fluorescence intensity of the complex, and the surface hydrophobicity was increased. The trend of the protein structure studied by Raman spectroscopy was similar to that of FTIR and fluorescence spectroscopy. When the HIU treatment was performed for 15 min and at 450 W power, the particle size of the complex was 451.85 ± 2.17 nm, and the solubility was 89.04 ± 0.19 %, indicating that the HIU treatment caused the spatial conformation of the protein to loosen and improved the functional properties of the complex. Confocal laser scanning microscopy (CLSM) revealed that the complex after HIU treatment exhibited improved dispersibility in water and smaller particle size. Gel electrophoresis results indicated that HIU treatment did not affect the protein subunits of the complex. Therefore, the selection of a suitable HIU treatment power can effectively improve the structural properties and solubility of SPI in the complex, and promote the application of the SPI-PC complex in food processing and industries.