Bioaccessibility, bioactivity and cell metabolism of dark chocolate phenolic compounds after in vitro gastro-intestinal digestion

From controlled transformed cocoa beans to chocolate: Bioactive properties, metabolomic profile, and in vitro bioaccessibility

This study aimed to characterize the changes in bioactive compounds associated with health benefits during the transformation of cocoa seeds into chocolate and in vitro gastrointestinal digestion. Flavan-3-ols (catechin, epicatechin), methylxanthines (theobromine, caffeine), total phenolic content, antioxidant activity, and metabolomic fingerprint were analyzed. The results indicated that processing stages led to a general decrease in bioactive compound content, attributed to factors such as temperature, pH, and diffusive phenomena. Roasting and chocolate processing particularly affected epicatechin and caffeine contents. In vitro digestion released compounds in response to enzymatic activity and system conditions, with a significant release of amino acids and peptides in the intestinal phase. Catechin and theobromine exhibited higher effective bioaccessibility. The antioxidant activity mirrored the quantification of individual compounds. This research provides valuable insights into the dynamic changes of chemical compounds in cocoa matrices throughout the transformation of cocoa seeds into chocolate and in vitro gastrointestinal digestion.

Storage stability of chocolate can be enhanced using locust protein-based film incorporated with E. purpurea flower extract-based nanoparticles

The study aimed to develop a locust protein (Loct-Prot)-based film to enhance the lipid oxidative and storage stability of chocolate. The E. purpurea flower extract based-nanoparticles (EFNPs) were developed using ultrasonication (500 W and 20 kHz for 10 min) following a green method of synthesis. The EFPNs were incorporated at different levels [T0 (0%), T1 (1.0%), T2 (1.5%), and T3 (2.0%)] to impart bioactive properties to the Loct-Prot-based films which were used for packaging of white chocolate during 90 days trial. The addition of EFPNs increased (P < 0.05) the density of the Loct-Prot-based film which in turn decreased (P < 0.05) the transmittance (%) and WVTR (water vapour transmission rate, mg/mt2) with increasing levels of addition. While brightness (L*) showed a decrease, redness (a*) and yellowness (b*) increased with increasing concentration of EFPNs. No significant (P > 0.05) effect was recorded on other physicomechanical parameters of the film. The addition of EFPNs (P < 0.05) increased the mean values of all the antioxidant and antimicrobial parameters (total flavonoid and phenolic contents, FRAP, DPPH, and ABTS activities, antioxidant release and inhibitory halos) of the film. The presence of Loct-Prot-based film decreased the lipid (TBARS and free fatty acids) and protein (total carbonyl content) oxidation of the chocolate samples during storage. A significant (P < 0.05) increase was observed in the antioxidant properties [FRAP (µM TE/100 g) and DPPH and ABTS activities (% inhibition)] of the chocolate samples after one month and the sensory and microbial qualities towards the end of the storage. The gastrointestinal digestion simulation showed a positive impact on the antioxidant properties of the chocolate. Based on our results, Loct-Prot-based film incorporated with EFPNs can be used to enhance the storage stability of chocolate during storage.

Cocoa powder and fermented jackfruit seed flour: A comparative cell-based study on their potential antioxidant and anti-inflammatory activities after simulated gastrointestinal digestion

BACKGROUND

Jackfruit seed flour can be used as a cocoa aroma replacer with similar technological properties. The purpose of this study was to investigate the in vivo toxicity and in vitro antioxidant activity of fermented jackfruit seed flour (Fjs) and non-alkaline cocoa powder (Nac).

RESULTS

Fjs and Nac extracts (Fjs-E and Nac-E) were produced and submitted to in vitro gastrointestinal digestion producing digested fractions named Fjs-D and Nac-D, respectively. Nac-E showed over two-fold higher oxygen radical absorbance capacity (ORAC) than Fjs-E. However, after simulated gastrointestinal digestion (in vitro), there were no significant differences between Nac-D and Fjs-D (P < 0.01). Similarly, the cellular antioxidant activity (CAA) of Nac-D and Fjs-D was not significantly different (P < 0.01). The anti-inflammatory assay in transgenic RAW 264.7 murine macrophages showed that Fjs-E did not affect cell viability up to 300 μg mL^-1 (P > 0.05) and reduced by 15% the release of TNF-α (P < 0.05). Fjs-D did not affect cell viability up to 300 μg mL^-1 (P > 0.05) and showed 58% reduction of NF-κB activation (P < 0.05), with no effects on TNF-α levels. Treatment with Nac-E up to 300 μg mL^-1 did not decrease cell viability (P > 0.05) and reduced the release of TNF-α levels by 34% and 66% at 100 and 300 μg mL^-1 , respectively (P < 0.05). Nac-D did not reduce the NF-κB activation or TNF-α levels at any tested concentration.

CONCLUSION

Collectively, these findings indicate that Fjs is a safe and promising functional ingredient with biological activities even after gastrointestinal digestion. © 2023 Society of Chemical Industry.

Germination and its role in phenolic compound bioaccessibility for black mustard grains: A study using INFOGEST protocol

Germination has been regarded as a promising natural process to improve the antioxidant properties of mustard. However, there ís one question to be solved in this area: does germination improve mustard phenolics' bioaccessibility? The aim of this study was to answer this question by using INFOGEST protocol to simulate in vitro digestion. Resveratrol, formononetin and cryptochlorogenic acid were identified for the first time as evaluated by liquid chromatography-mass spectrometry. In general, digestion positively impacted the antioxidant potential of soluble phenolics from non-germinated and germinated grains, which were probably released from cell wall matrix by digestive enzymes. Although digestion seemed to nullify the antioxidant improvement caused by germination, phenolic quantities were distinctive. The main difference was found for sinapic acid, as its concentration reached a value 1.75-fold higher in germinated digested mustard compared to non-germinated. The results obtained suggested that germination improved the phenolic bioaccessibility of mustard grains, which encourages its use and investigations.

Application of plant products in the synthesis and functionalisation of biopolymers

The burning of plastic trash contributes significantly to the problem of air pollution. Consequently, a wide variety of toxic gases get released into the atmosphere. It is of the utmost importance to develop biodegradable polymers that retain the same characteristics as those obtained from petroleum. In order to decrease the effect that these issues have on the world around us, we need to focus our attention on specific alternative sources capable of biodegrading in their natural environments. Biodegradable polymers have garnered much attention since they can break down through the processes carried out by living creatures. Biopolymers' applications are growing due to their non-toxic nature, biodegradability, biocompatibility, and environmental friendliness. In this regard, we examined numerous methods used to manufacture biopolymers and the critical components from which they get their functional properties. In recent years, economic and environmental concerns have reached a tipping point, increasing production based on sustainable biomaterials. This paper examines plant-based biopolymers as a good resource with potential applications in both biological and non-biological sectors. Scientists have devised various biopolymer synthesis and functionalization techniques to maximize its utility in various applications. In conclusion, recent developments in the functionalization of biopolymers through various plant products and their applications are discussed.

Bioaccessibility of phenolic compounds using the standardized INFOGEST protocol: A narrative review

The INFOGEST protocol creation was a watershed for phenolic bioaccessibility studies. Because of this important initiative to standardize bioaccessibility studies, data comparisons between different laboratories are now expedited. It has been eight years since the INFOGEST protocol creation, and three from the latest update. However, the current status in terms of phenolic bioaccessibility and how far different laboratories are from reaching a consensus are still unrevealed. In this sense, this narrative review considered an evaluation of different studies that applied the INFOGEST protocol to investigate the bioaccessibility of phenolic compounds. The central objective was to compile the main findings and consensus and to identify possible gaps and future opportunities. This approach intends to further facilitate the use of this protocol by professionals in the field of food science and technology and related areas, generating a reflection on the actual level of standardization of the method. Despite the differences in phenolic compounds from diverse food matrices, and their peculiar behavior, some trends could be elucidated, in terms of phenolic release, stability, and/or transformation upon in vivo digestion. In contrast, there was no general consensus regarding sample preparation, how to report results and the form to calculate bioaccessibility, making it difficult to compare different studies. There is still a long road to effectively standardize the results obtained for phenolic bioaccessibility using the INFOGEST protocol, which is also an opportunity in terms of food analysis that can impact the food industry, especially for the development of nutraceuticals and functional foods.

Bioaccessibility and Bioavailability of (-)-Epigallocatechin Gallate in the Bread Matrix with Glycemic Reduction

Bread has a high glycemic index (GI) and rich contents of quickly digestible carbohydrates, which is associated with insulin resistance and the risk of chronic diseases. (-)-Epigallocatechin Gallate (EGCG) is the primary catechin component that inhibits starch hydrolases, while the low release and absorption rates limit its utilization. In this study, EGCG was added to the bread matrix for fortification to reduce its glycemic index compared to white bread. EGCG fortification at 4% decreased the starch digestion rate of baked bread by 24.43% compared to unfortified bread and by 14.31% compared to white bread, with an identical amount of EGCG outside the matrix. Moreover, the predicted GI (pGI) was reduced by 13.17% compared to white bread. Further, 4% EGCG-matched bread enhanced the bioaccessibility and bioavailability of EGCG by 40.38% and 47.11%, respectively, compared to the control. The results of molecular docking demonstrated that EGCG had a higher binding affinity with α-amylase than with α-glucosidase, indicating that EGCG may effectively inhibit the accumulation of carbs during starch digestion. Thus, EGCG can be used as a functional ingredient in bread to reduce its glycemic potential, and the bread matrix can be used as a carrier for EGCG delivery to enhance its bioaccessibility and bioavailability.

Interactions between Salivary Proteins and Dietary Polyphenols: Potential Consequences on Gastrointestinal Digestive Events

The present review documents the current knowledge and hypotheses on how polyphenols-saliva interactions may modulate the bioaccessibility or bioavailability of nutrients and highlights research prospects in the field. After an updated description of the different classes of dietary polyphenols and their modifications by food processing or digestion, an overview of interactions between salivary proteins and polyphenols (with an emphasis on tannins) is provided. In vitro studies show that the solubility of salivary protein-tannin complexes in gastric conditions depends on the degree of tannin polymerization, while complexes are partly solubilized by bile salts. Salivary proteins-polyphenols interactions may affect digestive processes. For example, polyphenols can bind to and inhibit salivary amylase, with downstream consequences on starch digestion. Some salivary proteins (PRPs) prevent tannin-induced reduced protein digestibility, probably through binding tannins before they interact with digestive proteases. Salivary proteins may also act as scavenger molecules to limit the intestinal uptake of tannins.

High-Pressure Technologies for the Recovery of Bioactive Molecules from Agro-Industrial Waste

Large amounts of food waste are produced each year. These residues require appropriate management to reduce their environmental impact and, at the same time, economic loss. However, this waste is still rich in compounds (e.g., colorants, antioxidants, polyphenols, fatty acids, vitamins, and proteins) that can find potential applications in food, pharmaceutical, and cosmetic industries. Conventional extraction techniques suffer some drawbacks when applied to the exploitation of food residues, including large amounts of polluting solvents, increased time of extraction, possible degradation of the active molecules during extraction, low yields, and reduced extraction selectivity. For these reasons, advanced extraction techniques have emerged in order to obtain efficient residue exploitation using more sustainable processes. In particular, performing extraction under high-pressure conditions, such as supercritical fluids and pressurized liquid extraction, offers several advantages for the extraction of bioactive molecules. These include the reduced use of toxic solvents, reduced extraction time, high selectivity, and the possibility of being applied in combination in a cascade of progressive extractions. In this review, an overview of high-pressure extraction techniques related to the recovery of high added value compounds from waste generated in food industries is presented and a critical discussion of the advantages and disadvantages of each process is reported. Furthermore, the possibility of combined multi-stage extractions, as well as economic and environmental aspects, are discussed in order to provide a complete overview of the topic.

Physicochemical, Antioxidant, Microstructural Properties and Bioaccessibility of Dark Chocolate with Plant Extracts

In this study, dark chocolates (DCh) containing zinc lactate (ZnL) were enriched with extracts from elderberries (EFrE), elderflowers (EFlE), and chokeberries (ChFrE) to improve their functional properties. Both dried plant extracts and chocolates were analyzed for antioxidant capacity (AC) using four different analytical methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), cupric ion-reducing antioxidant capacity (CUPRAC), and ferric-reducing antioxidant power (FRAP), while total phenolic content (TPC) was determined by Folin-Ciocalteu (F-C) assay. An increase in antioxidant properties of fortified chocolates was found, and the bioaccessibility of their antioxidants was evaluated. The highest AC and TPC were found in ChFrE and chocolate with chokeberries (DCh + ChFrE) before and after simulated in vitro digestion. Bioaccessibility studies indicated that during the simulated digestion the AC of all chocolates reduced significantly, whereas insignificant differences in TPC results were observed between chemical and physiological extracts. Moreover, the influence of plant extracts on physicochemical parameters such as moisture content (MC), fat content (FC), and viscosity of chocolates was estimated. Furthermore, scanning electron microscopy with dispersive energy spectroscopy (SEM-EDS) was used to analyze surface properties and differences in the chemical composition of chocolates without and with additives.

Advances in static in vitro digestion models after the COST action Infogest consensus protocol

In vitro digestion models are essential to predictively evaluate the bioaccessibility and bioactivity of food molecules or natural products. Dynamic models better simulate the gastrointestinal conditions as they reproduce similar physiological environments. Despite this, static methods, also known as biochemical methods, represent a simple and useful approach for the study of different types of molecules, with a broad applicability in the nutritional, pharmaceutical, and toxicological fields. In addition, static models can be validated, avoiding the disadvantage of a difficult reproducibility of dynamic in vitro systems and inter-individual variations of in vivo experiments. A crucial point in the standardization of static models was the COST Action Infogest in 2014, which elaborated an international consensus static digestion method to harmonize experimental conditions and has general guidelines, thus allowing the comparison of studies and data. The aim of our review is to underline the impact of the Infogest consensus method and the development and evolution of in vitro static methods in the following years, with a focus on food applications.

Stability and anti-topoisomerase activity of phenolic compounds of Capsicum annuum "Serrano" after gastrointestinal digestion and in vitro colonic fermentation

"Serrano" pepper is extensively used in Mexican cuisine. The aim of this study was to identify the bioaccessible phenolic compounds (PC) of "Serrano" pepper as well as short-chain fatty acids (SCFA) produced and PC bioconverted using an in vitro step-wise gastromimetic model of the intestinal digestion and anaerobic fermentation of the isolated indigestible fraction (IF). The anti-topoisomerase activity of the fermented samples was also evaluated. PC bioaccessibility was about 45% in the small intestine. Chlorogenic acid and capsaicin were identified during the intestinal digestion, while quercetin was identified as available to the gut microbiota. After 48-h fermentation, SCFA molar ratio was 77:11:12 for acetic, propionic and butyric acid. The PC identified in IF and after 12 h of fermentation showed anti-topoisomerase activity. A synergistic effect among the PC and gut metabolites mixture was observed, which indicates a possible antiproliferative mechanism that should be tested in further studies.

In vitro bioaccessibility of amino acids and bioactive amines in 70% cocoa dark chocolate: What you eat and what you get

Chocolate is an important source of free bioactive amines and amino acids which play important roles in human health. Considering the limited information on the bioaccessibility of these compounds from chocolate, the objective of this study was to characterize their profiles and bioaccessibility in 70% cocoa dark chocolate through in vitro simulation of oral, gastric and intestinal digestions. Seven amines were detected; polyamines were predominant before in vitro digestion, whereas tyramine, cadaverine and spermidine after digestion. All amines showed high bioaccessibility with slight influence of digestive enzymes. Amines increased after gastrointestinal digestion: tyramine (13-fold), tryptamine (9-fold), others (2.4-4.2-fold) and histamine appeared. All amino acids, GABA and ammonia were detected in chocolate, and their contents increased after in vitro digestion due to digestive enzymes (4.6, 2.8 and 2.1, respectively). Dark chocolate protein is a good source of tryptophan, phenylalanine + tyrosine, isoleucine, histidine, but limiting for lysine, leucine, and threonine.

Processing of four different cooking methods of Oudemansiella radicata: Effects on in vitro bioaccessibility of nutrients and antioxidant activity

The purpose of this study is to evaluate the bioaccessibility of nutrients and antioxidant activity of O. radicata after subjecting to four types of domestic cooking and followed by in vitro digestion. The result demonstrated that the group with the lowest amino acid release and the degree of protein hydrolysis (5.6%) was frying, but both reducing sugar content and antioxidant activity were the highest. The composition of fatty acids was different than undigested samples, especially the relative content of linolenic acid was significantly decreased (e.g., 34.49 to 8.23%, boiled). The difference of the minerals bioaccessibility was slightly affected by the cooking method, but mainly related to their natural properties, such as the highest phosphorus (62.73%) and the lowest iron (21.53%) in the steaming. The above data provides a starting point for the design of processes at an industrial and gastronomic level.

Rice and common bean blends: Effect of cooking on in vitro starch digestibility and phenolics profile

This study aims to evaluate the effects of in vitro digestion of rice and common bean blends on phenolics content and profile. Black and carioca beans were used as common bean sources. Blends consisted of 25:75, 50:50, and 75:25 polished rice:beans (w/w). Pure rice or pure beans were also analyzed. Phenolic compounds were determined in raw, cooked, and digested samples. The glucose release through in vitro digestion was slower as the proportion of black beans or carioca beans increased. Starch digestibility ranged between 41.1 in 100% carioca bean to 84.4% in 100% rice. Hydroxybenzoic acid, ferulic acid, p-coumaric acid, catechin, and epicatechin were the most abundant phenolics detected in the studied samples. Considering the content of phenolic compounds determined in the raw, cooked, and digested grains, only a small fraction was available for absorption in the gut, with amounts varying from 0.1 to 0.6 μg·g^-1.

Recent advances and comparisons of conventional and alternative extraction techniques of phenolic compounds

Phenolic compounds are a group of secondary metabolites produced by plants under stressful conditions. Phenolic compounds play an important role in the prevention and treatment of certain illnesses and are exploited by the food and pharmaceutical industries. Conventional methods are commonly used as models to compare the efficiencies of alternative extraction methods. Among alternative extraction processes, microwave-assisted extraction (MAE), pressurized liquid extraction (PLE), supercritical fluid extraction (SFE) and ultrasonic-assisted extraction (UAE) are the most studied. These methods produce extracts rich in phenolic compounds using moderate temperatures, short extraction times, and solvents generally recognized as safe. The combination of extraction time and temperature plays a critical role in the stability of the compounds. Solvents of higher polarity enhance the extraction of phenolic compounds. The use of the ethanol-water mixture for MAE, PLE, and UAE is recommended. MAE and UAE involve shorter extraction times than do PLE and SFE. SFE requires a low average temperature (40 °C). MAE produces the highest total phenolic content [227.63 mg GAE/g dry basis (d.b.)], followed by PLE (173.65 mg GAE/g d.b.), UAE (92.99 mg GAE/g d.b.) and SFE (37 mg GAE/g d.b.). Extraction yields and recovery rates of the phenolic compounds can be enhanced by combining and integrating extraction methods.

Antiproliferative Activity and Cell Metabolism of Hydroxycinnamic Acids in Human Colon Adenocarcinoma Cell Lines

In this study, we investigated the antiproliferative activity and the stability and metabolic fate of the main dietary hydroxycinnamates, using two colonic adenocarcinoma cell models (Caco-2 and SW480). Dihydrocaffeic and dihydroferulic acids were the most effective against cell proliferation in both cell lines with IC₅₀ values of 71.7 ± 1.1 and 83.1 ± 1.1 μmol/L, respectively ( P < 0.05) in Caco-2. At 200 μmol/L, caffeic and ferulic acids inhibited SW480 proliferation by 40.8 ± 1.6 and 59.9 ± 1.3%, respectively. Hydroxycinnamic acids with a catechol-type structure were degraded in Caco-2 cell medium, resulting in the production of H₂O₂. Intracellular Caco-2 UDP-glucuronosyltransferases and catechol- O-methyltransferases were able to form glucuronide and methyl conjugates. However, only the sulfate conjugates were detected after incubation with SW480. In addition, simple hydroxycinnamates were released from quinic and aspartic conjugates. The remarkable effect of dihydrocaffeic and dihydroferulic acids against cell proliferation is of paramount importance, since these compounds are the main metabolites detectable at the colonic level.