GutSelf: Interindividual Variability in the Processing of Dietary Compounds by the Human Gastrointestinal Tract

Nutritional research is currently entering the field of personalized nutrition, to a large extent driven by major technological breakthroughs in analytical sciences and biocomputing. An efficient launching of the personalized approach depends on the ability of researchers to comprehensively monitor and characterize interindividual variability in the activity of the human gastrointestinal tract. This information is currently not available in such a form. This review therefore aims at identifying and discussing published data, providing evidence on interindividual variability in the processing of the major nutrients, i.e., protein, fat, carbohydrates, vitamins, and minerals, along the gastrointestinal tract, including oral processing, intestinal digestion, and absorption. Although interindividual variability is not a primary endpoint of most studies identified, a significant number of publications provides a wealth of information on this topic for each category of nutrients. This knowledge remains fragmented, however, and understanding the clinical relevance of most of the interindividual responses to food ingestion described in this review remains unclear. In that regard, this review has identified a gap and sets the base for future research addressing the issue of the interindividual variability in the response of the human organism to the ingestion of foods.     

Possible adducts formed between hydroxymethylfurfural and selected amino acids,and their release in simulated gastric model

This work aimed to investigate the reactivity of hydroxymethylfurfural (HMF) with selected amino acids, to identify the produced adducts and to clarify whether or not the adducts release HMF after their digestion under gastric conditions. Results showed that cysteine, glycine and lysine can deplete the added HMF, and their reactivity increased with increasing pH and temperature. Cysteine (25 μmol mL^?1) depleted 91.0% of the added HMF (315.3 μg mL^?1) at 40 °C in 15 min, lysine did not eliminate HMF until 80 °C, and glycine started to eliminate HMF at 100 °C. Four adducts for cysteine, three adducts for lysine and only one adduct for glycine were identified through HPLC–MS–MS after they reacted with HMF. The adducts formed from the reaction mixture of cysteine, lysine and glycine with HMF only released 1.7%, 2.6% and 10.5% of eliminated HMF, respectively, after their digestion in simulated gastric conditions.     

Determination of toxic and essential elements in sunflower honey from Thrace Region,Turkey

The aim of this study was to determine the levels of copper (Cu), manganese (Mn), zinc (Zn), iron (Fe), cadmium (Cd), lead (Pb), chromium (Cr), nickel (Ni) and selenium (Se) in sunflower honeys obtained from Thrace Region of Turkey. Trace and toxic element determination was performed by atomic absorption spectrometry after microwave digestion. The accuracy of the method was checked by the standard reference material, NIST‐SRM 1515 Apple leaves. The maximum contents of trace and toxic elements in honey samples from Kesan (polluted area) were found as 0.46, 0.82, 1.98, 14.0, 9.86 μg kg^?1, 0.48 mg kg^?1, 137, 115 and 290 μg kg^?1 for Cu, Mn, Zn, Fe, Cd, Pb, Cr, Ni and Se, respectively.     

Assessing the impact of palmitic,myristic and lauric acids on hydrogen production from glucose fermentation by mixed anaerobic granular cultures

The effects of lauric (LUA), myristic (MA), palmitic (PA), and a mixture of myristic:palmitic (MA:PA) acids on hydrogen (H₂) production from glucose degradation using anaerobic mixed cultures were assessed at 37 °C with an initial pH set at 5.0 and 7.131 mM of each acid. The maximum H₂ yield (2.53 ± 0.18 mol mol⁻¹ glucose) was observed in cultures treated with PA. A principal component analysis (PCA) of the by-products and the microbial population data sets detected similarities between the controls and PA treated cultures; however, differences were observed between the controls and PA treated cultures in comparison to the MA and LUA treated cultures. The flux balance analysis (FBA) showed that PA decreased the quantity of H₂ consumed via homoacetogenesis compared to the other LCFAs. The control culture was dominated by Thermoanaerovibrio acidaminovorans (60%), Geobacillus sp. and Eubacterium sp. (28%), while Clostridium sp. was less than 1%. Treatment with PA, MA, MA:PA, or LUA increased the H₂ producers (Clostridium sp. and Bacillus sp.) population by approximately 48, 67, 86, and 86%, respectively.     

Changes in the phenolic contents and antioxidant activities of citrus peels from different cultivars after in vitro digestion

The aim of this study was to investigate the effects of in vitro digestion on the phenolic contents and antioxidant activities of citrus peels. Three different varieties of citrus peels (mandarin, ponkan and red tangerine) were treated with simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). The results showed that the SGF or SIF treatments of the citrus peels did not significantly increase the total phenolic content (TPC) or total flavonoid content (TFC), except for that of the TFC of ponkan peel treated with SGF. However, simulated in vitro digestion did improve the antioxidant activities measured with FRAP and ABTS methods. The effect of SGF was more positive than those of SIF for the FRAP assay, but the opposite was true for ABTS. Notably, both simulated digestion techniques decreased the DPPH free radical scavenging abilities. Simulated digestion in vitro changed the antioxidant activities of the citrus peels.     

In vitro digestibility of phenolic compounds from edible fruits: could it be explained by chemometrics?

The health benefits of phenolic compounds depend on the ingested amount, molecular diversity and gastrointestinal digestibility. The phenolic profile of eight fruits (blackberry, blueberry, strawberry, raspberry, mulberry, pomegranate, green and red globe grapes) was chemometrically associated with their in vitro digestibility (oral, gastric, intestinal). Extractable phenols, flavonoids and anthocyanins strongly correlated with each other (r ≥ 0.84), proanthocyanidins with anthocyanins (r = 0.62) and hydrolysable phenols with both extractable phenols (r = 0.45) and proanthocyanidins (r = ?0.54). Two principal components explained 93% of the variance [61% (free‐phenols), 32% (bounded‐phenols)], and four clusters were confirmed by hierarchical analysis, based in their phenolic richness (CLT 1‐4: low to high) and molecular diversity. In vitro digestibility of extractable phenols and flavonoids was blackberry (CLT‐4)> raspberry (CLT‐2)> red grape (CLT‐1) related to their phenolic richness (r ≥ 0.96; P < 0.001), but anthocyanins’ digestibility was pH‐dependent. Chemometrics is useful to predict the in vitro digestibility of phenolic compounds in the assayed fruits.     

Changes in in vitro protein digestion of retort‐pouched pork belly during 120‐day storage

To investigate the effect of long‐term storage on in vitro protein digestion of the retort‐pouched pork belly. The products were stored at 25 °C for 0, 30, 60 and 120 days and digested with pepsin and trypsin at each time point. SDS‐PAGE and LC‐MS‐MS were applied to separate and identify proteins and their digested products. In vitro protein digestibility decreased from 47.7% after 60‐day storage to 25.4% after 120‐day storage for the samples digested by pepsin, and from 63.9% to 45.7% for the samples digested by pepsin and trypsin at corresponding time points. LC‐MS‐MS demonstrated changes in peptide composition and abundance with storage time. Long‐term storage could deteriorate nutritive values of meat products by reducing digestible protein content.     

Incorporation of fish by-product into the semi-continuous anaerobic co-digestion of pre-treated lignocellulose and cow manure,with recovery of digestate's nutrients

Norway's fish processing industry generates large amounts of fish waste every year. The high-risk waste fraction with most of its oil removed has not yet been tested for energy production. The stability of an anaerobic digestion process that incorporates this material with steam exploded Salix and cow manure was tested using mesophilic, semi-continuous laboratory-scale digesters. The effects of recycling the liquid digestate fraction were also investigated. The removal of ammonium (NH₄⁺) and phosphate (PO₄³⁻) from the rejected digestate using struvite precipitation and bentonite adsorption were tested to generate a nutrient-enriched, final solid fertiliser. Adding 20% fish by-product (volatile solids basis) increased methane yields by 35%, while recycling the digestate caused a slight increase. The NH₄⁺–N levels reached 4–5 g l⁻¹ in the reactors with recirculation and fish feed. Although these levels may threaten methanogenesis, the stability of the process was maintained during the entire period due to the good balance between the lignocellulose, proteins and fats provided by the co-digestion mixture and the positive effects of recirculation. The NH₄⁺ and PO₄³⁻ were successfully removed from the rejected liquid digestate. The reductions using struvite reached 87% and 60% (pH 9.5 and Mg²⁺:NH₄⁺:PO₄³⁻ ratio of 1.2:1:1), while bentonite achieved 82% and 52%, respectively.