Influence of In Vitro Digestion on Antioxidant Activity of Enriched Apple Snacks with Grape Juice

Inhibition mechanism of starch digestion by luteolin, eriodictyol, and their complex in vitro: Multispectral, kinetic, and theoretical calculations analysis

Peanut shell polyphenol possesses hypoglycemic activity, however, its inhibitory effects and mechanisms on starch digestion remain unclear. This study investigated the inhibitory effects of its main components: luteolin, eriodictyol, and their complex (luteolin-eriodictyol) on starch digestion. The results indicated that all three polyphenols inhibited starch digestion, primarily by inhibiting digestive enzymes activity. Luteolin-eriodictyol exhibited the strongest inhibition, with a 15.87 ± 0.81 % inhibition rate in starch digestion, and IC50 values of 455 ± 9.38 μg/mL for α-amylase and 25 ± 1.34 μg/mL for α-glucosidase. Quantum chemical analysis revealed that luteolin-eriodictyol exhibited greater molecular stability compared to its monomers. Its strong inhibitory effect was attributed to its high environmental stability and multiple binding sites on digestive enzymes. Spectroscopic analysis and molecular docking confirmed that luteolin, eriodictyol, and luteolin-eriodictyol combined with digestive enzymes through hydrogen bonding, hydrophobic interaction, and van der Waals force. These bindings changed the secondary and tertiary structures of digestive enzymes, leading to inhibitory effects. This study provides novel insights into the synergistic potential of dietary polyphenols in managing diabetes and highlights the value of combining polyphenols to enhance bioactivity.

Investigating the potential of yacon (Smallanthus sonchifolius) juice in the development of organic apple-based snacks

This study investigates the potential of yacon (Smallanthus sonchifolius) juice for the development of prebiotic-rich organic apple-based snacks. Yacon syrup, primarily composed of fructan, inulin, fructooligosaccharides (FOS), and free sugars, represents a promising nutraceutical product. Its great potential in food processing, particularly as an innovative source of prebiotics, has been demonstrated both in vitro and in vivo since it is fermented specifically by lactobacilli and bifidobacteria. Our objective was to explore the feasibility of employing vacuum impregnation process to incorporate yacon juice into organic apples, followed by hot air drying for the formulation of dried organic apple-based snacks with health-enhancing attributes. We assessed the prebiotic and physicochemical characteristics of the impregnated snacks, also considering 50 days of storage at room temperature. Vacuum impregnation and air drying produced dried apple slices impregnated with yacon juice with good quality and stability. Higher levels of fructan (16-fold difference compared to non-impregnated apples) in the apple slices increased their prebiotic potential, promoting the growth and viability of cells within simulated intestinal fluid, including strains of Bifidobacterium animalis subsp. lactis BB -12, Bifidobacterium breve DSM 20091, Bifidobacterium longum subsp. infantis DSM 20088, Lacticaseibacillus rhamnosus GG and Lacticaseibacillus rhamnosus C112, even after prolonged storage. Remarkably, the physicochemical parameters of the impregnated and dried apple slices remained nearly constant and akin to the control samples. Therefore, the combination of vacuum impregnation and air drying has the potential to be used to produce enriched prebiotic organic apple snacks, providing consumers with additional health benefits, including enhanced gut health, with its associated implications, and increased satiety. This innovation could contribute to the development of health-promoting food products with improved nutritional profiles.

Bioaccessibility of Phenolic Compounds, Resistant Starch, and Dietary Fibers from Australian Green Banana during In Vitro Digestion and Colonic Fermentation

Green bananas contain a substantial amount of resistant starch (RS), dietary fiber (DF), and phytochemicals, which exhibit potent antioxidant capabilities, primarily attributable to the abundance of polyphenols. The objective of this study was to assess the variations in the contents and bioaccessibility of RS, DF, and phenolic compounds in three types of Australian green bananas (Cavendish "Musa acuminata", Ladyfinger "Musa paradisiaca L.", and Ducasse "Musa balbisiana"), along with their antioxidant capacities, and the production of short-chain fatty acids (SCFAs) following in vitro simulated gastrointestinal digestion and colonic fermentation. The studied cultivars exhibited significant levels of RS, with Ladyfinger showing the greatest (49%). However, Ducasse bananas had the greatest DF concentration (38.73%). Greater TPC levels for Ladyfinger (2.32 mg GAE/g), as well as TFC and TTC (0.06 mg QE/g and 3.2 mg CE/g, respectively) in Cavendish, together with strong antioxidant capacities (DPPH, 0.89 mg TE/g in Cavendish), have been detected after both intestinal phase and colonic fermentation at 12 and 24 h. The bioaccessibility of most phenolic compounds from bananas was high after gastric and small intestinal digestion. Nevertheless, a significant proportion of kaempferol (31% in Cavendish) remained detectable in the residue after colonic fermentation. The greatest production of SCFAs in all banana cultivars was observed after 24 h of fermentation, except valeric acid, which exhibited the greatest output after 12 h of fermentation. In conclusion, the consumption of whole green bananas may have an advantageous effect on bowel health and offer antioxidant characteristics.

Effect of ficin-hydrolyzed wheat gluten on bread quality and in vitro antioxidant activity before and after simulated gastrointestinal digestion

This study aimed to investigate the effect of adding ficin-hydrolyzed wheat gluten at different levels (0%, 1%, 2%, 4%) on bread quality, and in vitro antioxidant activity before and after simulated gastrointestinal digestion. Our findings revealed that the incorporation of the generated wheat gluten hydrolysates (WGH) up to 4 g per 100 g flour positively affected the technological and physical-chemical characterizations of breads, including dough rheological properties, color, specific volume, and moisture. The texture profile analysis indicated reductions in hardness, springiness, and chewiness of the breads, and confirmed anti-staling properties during storage. The enriched breads received satisfactory scores from the sensory panel and were perceived as less stale after a 4-day period of storage. The aroma score of the 4% WGH bread was significantly higher than other treatments. Regarding taste, the 4% WGH bread scored the lowest, but the obtained value was not statistically significant. The enriched breads exhibited DPPH, ABTS radical scavenging, and Fe2+ chelation abilities that increased in response to higher levels of hydrolysate incorporation, and these antioxidant activities were enhanced after simulated gastrointestinal digestion. Our findings confirm that it is possible to apply ficin-generated WGH to enhance physicochemical, nutritional, and biological quality of bread.

Processing of Enriched Pear Slices with Blueberry Juice: Phenolics, Antioxidant, and Color Characteristics

This study evaluated the effectiveness of phenolic compound incorporation from blueberry juice into pear slices (PS) using a combination of ohmic heating (OH) and vacuum impregnation (VI), followed by air-drying (AD) or freeze-drying (FD). Our results showed that OH increased the content of bioactive compounds and antioxidant capacity of blueberry juice, with the optimal OH condition set at 50 °C for 20 min under an electric field of 13 V·cm^-1. Furthermore, the combination of VI and OH was efficient in enriching PS with bioactive compounds from blueberry juice (such as cyanidin and epigallocatechin), with the optimal VI/OH condition set at 50 °C for 90 min under an electric field of 7.8 V·cm^-1. Moreover, anthocyanin pigments from blueberry juice affected the color parameters of PS by increasing the a* parameter and decreasing the b* and L* parameters. However, both FD and AD (at 40, 50, and 60 °C) negatively affected (p ≤ 0.05) the phenolic content and antioxidant capacity. Notably, AD at 60 °C showed the highest levels of phenolic compounds and antioxidant potential for both impregnated and non-impregnated PS.

Dragon fruit-kiwi fermented beverage: In vitro digestion, untargeted metabolome analysis and anti-aging activity in Caenorhabditis elegans

The research on the development of dragon fruit and kiwi fruit through LAB-yeast compound fermentation is very limited, and there are few related fermentation products on the market. The purpose of this study was to evaluate the stability of the antioxidant capacity of fermented beverages (FB) through in vitro simulated digestion, to evaluate the changes in metabolites of juice after fermentation through untargeted metabolomics, and used Caenorhabditis elegans as a model to evaluate its anti-aging activity. The results showed that FB not only has good in vitro antioxidant activity, but also the total phenol content (TPC), total flavonoid content (TFC), ABTS scavenging ability, and hydroxyl radical scavenging ability of FB were significantly increased during gastric digestion and intestinal digestion. Metabolomics showed that the contents of phenols and flavonoids related to antioxidant increased after fermentation, and fermentation had a significant effect on organic acids and amino acids in FB. Finally, compared with the control group, although the original concentration of FB has a side-toxic effect on nematodes, the mean lifespan of C. elegans fed with 1.56% FB increased by 18.01%, SOD activity significantly increased by 96.16% and MDA content significantly decreased by 40.62%. FB has good antioxidant activity in vitro and in vivo, and the antioxidant activity is stable during the simulated digestion process.

In Vitro Gastrointestinal Bioaccessibility, Bioactivities and Colonic Fermentation of Phenolic Compounds in Different Vigna Beans

Beans are widely consumed throughout the world, rich in non-nutrient phenolic compounds and other bioactive constituents, including alkaloids, lectins, and others. However, research about in vitro digestion impacts on the changes of bioactive compounds' release and related antioxidant potential in different Vigna beans is limited. This research aimed to assess the modifications that occur in the content and bioaccessibility of phenolic compounds in four Vigna samples (adzuki bean, black urid whole, black eye bean, and mung bean), their antioxidant properties, and short chain fatty acids (SCFAs) production through static in vitro gastrointestinal digestion and colonic fermentation. Adzuki bean exhibited relatively higher total phenolic content (TPC; 4.76 mg GAE/g) and antioxidant activities after in vitro digestion. The black eye beans' total flavonoid content (0.74 mg QE/g) and total condensed tannins (10.43 mg CE/g) displayed higher tendencies. For colonic fermentation, the greatest TPC value of entire samples was detected through a 2-h reaction. In most selected beans, phenolic compounds were comparably more bioaccessible during the oral phase. Acetic acid showed the highest level through SCFAs production, and the total SCFAs in adzuki beans was the greatest (0.021 mmol/L) after 16-h fermentation. Adzuki beans may be more beneficial to gut health and possess a stronger antioxidant potential after consumption.

Comparison of Flavonoid O-Glycoside, C-Glycosideand Their Aglycones on Antioxidant Capacity and Metabolism during In Vitro Digestion and In Vivo

Flavonoids are well known for their extensive health benefits. However, few studies compared the differences between flavonoid O-glycoside and C-glycoside. In this work, flavonoid O-glycoside (isoquercitrin), C-glycoside (orientin), and their aglycones (quercetin and luteolin) were chosen to compare their differences on antioxidant activities and metabolism during in vitro digestion and in vivo. In vitro digestion, the initial antioxidant activity of the two aglycones was very high; however, they both decreased more sharply than their glycosides in the intestinal phase. The glycosidic bond of flavonoid O-glycoside was broken in the gastric and intestinal stage, while the C-glycoside remained unchanged. In vivo, flavonoid O-glycoside in plasma was more elevated than C-glycoside on the antioxidant activity; however, flavonoid C-glycoside in urine was higher than O-glycoside. These results indicate that differences of flavonoid glycosides and their aglycones on antioxidant activity are closely related to their structural characteristics and metabolism in different samples. Aglycones possessed higher activity but unstable structures. On the contrary, the sugar substituents reduced the activity of flavonoids while improving their stability and helping to maintain antioxidant activities after digestion. Especially the C-glycoside was more stable because the stability of the C–C bond is higher than that of the C–O bond, which contributes to the difference between flavonoid O-glycoside and C-glycoside on the absorption and metabolism in vivo. This study provided a new perspective for comparing flavonoid O-glycoside, flavonoid C-glycoside, and their aglycones on their structure–activity relationship and metabolism.

Preparation and characterization of nanoemulsions of curcumin and echium oil

The search for the plant origin bioactive compounds is increasing over animal origin compounds. Echium oil (EO) contains high amounts of plant based omega-3 fatty acids. Moreover, curcumin addition may increase the release of these omega-3 fatty acids during digestion. The study's objective is to determine the bioaccessibility of curcumin in simulated intestinal digestion conditions and the release behavior of fatty acids of echium oil from nanoemulsions. We prepared curcumin and EO nanoemulsions with a microfluidizer using two different concentrations of surfactant, Tween 80 (5% and 10%). Emulsion stability tests, antioxidant analysis, in vitro oil release and fatty acid composition assays were conducted. Results showed that curcumin-containing nanoemulsions provide higher radical scavenging activity than the EO nanoemulsions. In addition, in vitro bioaccessibility of curcumin after in vitro simulated intestinal digestion was calculated as 35.5%. Gas chromatography results of the digested nanoemulsions revealed that curcumin addition decreases oleic acid release while increasing stearidonic acid (SDA) release.

•

Curcumin addition increased antioxidant activities of EO nanoemulsions.

•

Curcumin incorporated nanoemulsions had significantly higher SDA content after in vitro digestion.

•

In nanoemulsion form, in vitro curcumin bioaccessibility was 35.5%.

Antioxidants Bioaccessibility and Lactobacillus salivarius (CECT 4063) Survival Following the In Vitro Digestion of Vacuum Impregnated Apple Slices: Effect of the Drying Technique, the Addition of Trehalose, and High-Pressure Homogenization

To benefit the health of consumers, bioactive compounds must reach an adequate concentration at the end of the digestive process. This involves both an effective release from the food matrix where they are contained and a high resistance to exposure to gastrointestinal conditions. Accordingly, this study evaluates the impact of trehalose addition (10% w/w) and homogenization (100 MPa), together with the structural changes induced in vacuum impregnated apple slices (VI) by air-drying (AD) and freeze-drying (FD), on Lactobacillus salivarius spp. salivarius (CECT 4063) survival and the bioaccessibility of antioxidants during in vitro digestion. Vacuum impregnated apple slices conferred maximum protection to the lactobacillus strain during its passage through the gastrointestinal tract, whereas drying with air reduced the final content of the living cells to values below 10 cfu/g. The bioaccessibility of antioxidants also reached the highest values in the VI samples, in which the release of both the total phenols and total flavonoids to the liquid phase increased with in vitro digestion. The addition of trehalose and homogenization at 100 MPa increased the total bioaccessibility of antioxidants in FD and AD apples and the total bioaccessibility of flavonoids in the VI samples. Homogenizing at 100 MPa also increased the survival of L. salivarius during in vitro digestion in FD samples.

Effect of Filtrated Osmotic Solution Based on Concentrated Chokeberry Juice and Mint Extract on the Drying Kinetics, Energy Consumption and Physicochemical Properties of Dried Apples

BACKGROUND

Filtration of osmotic solution affects selective penetration during osmotic dehydration (OD), and after drying is finished, this can influence the chemical composition of the material, which is also modified by OD.

METHODS

Osmotic dehydration was carried out in filtrated and non-filtrated concentrated chokeberry juice with the addition of mint infusion. Then, this underwent convective drying, vacuum-microwave drying and combined convective pre-drying, followed by vacuum-microwave finishing drying. Drying kinetics were presented and mathematical models were selected. The specific energy consumption for each drying method was calculated and the energy efficiency was determined.

RESULTS AND DISCUSSION

The study revealed that filtration of osmotic solution did not have significant effect on drying kinetics; however, it affected selective penetration during OD. The highest specific energy consumption was obtained for the samples treated by convective drying (CD) (around 170 kJ·g-1 fresh weight (fw)) and the lowest for the samples treated by vacuum-microwave drying (VMD) (around 30 kJ·g-1 fw), which is due to the differences in the time of drying and when these methods are applied.

CONCLUSIONS

Filtration of the osmotic solution can be used to obtain the desired material after drying and the VMD method is the most appropriate considering both phenolic acid content and the energy aspect of drying.

In Vitro Gastrointestinal Digestion Impact on the Bioaccessibility and Antioxidant Capacity of Bioactive Compounds from Tomato Flours Obtained after Conventional and Ohmic Heating Extraction

In times of pandemic and when sustainability is in vogue, the use of byproducts, such as fiber-rich tomato byproducts, can be an asset. There are still no studies on the impact of extraction methodologies and the gastrointestinal tract action on bioactive properties. Thus, this study used a solid fraction obtained after the conventional method (SFCONV) and a solid fraction after the ohmic method (SFOH) to analyze the effect of the gastrointestinal tract on bioactive compounds (BC) and bioactivities. Results showed that the SFOH presents higher total fiber than SFCONV samples, 62.47 ± 1.24–59.06 ± 0.67 g/100 g DW, respectively. Both flours present high amounts of resistant protein, representing between 11 and 16% of insoluble dietary fiber. Furthermore, concerning the total and bound phenolic compounds, the related antioxidant activity measured by 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical cation decolorization assay presented significantly higher values for SFCONV than SFOH samples (p < 0.05). The main phenolic compounds identified in the two flours were gallic acid, rutin, and p-coumaric acid, and carotenoids were lycopene, phytofluene, and lutein, all known as health promoters. Despite the higher initial values of SFCONV polyphenols and carotenoids, these BCs’ OH flours were more bioaccessible and presented more antioxidant capacity than SFCONV flours, throughout the simulated gastrointestinal tract. These results confirm the potential of ohmic heating to modify the bioaccessibility of tomato BC, enhancing their concentrations and improving their antioxidant capacity.