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This study aims to provide information on the behaviour and biopersistence rate (BP) of metallic nanoparticles (Ag-NPs, TiO2-NPs, ZnO-NPs) naturally occurring in canned seafood and subjected to static in vitro digestion. Single particle ICP-MS analysis was performed to determine NPs distribution and concentrations in oral, gastric, and intestinal digests. Depending on the conditions of the digestive phase and the sample matrix, the phenomena of agglomeration and dispersion were highlighted and confirmed by Dynamic Light Scattering (DLS) technique. In standard suspensions, Ag-NPs had lower biopersistence (BP) than ZnO and TiO2-NPs (BP 34%, 89% and >100%, respectively). Among Ag-NPs and TiO2-NPs naturally present in the food matrix, those in canned tuna were more degradable than those in canned clam (BP Ag-NPs 36% vs. > 100%; BP TiO2-NPs 96% vs. > 100%), while BP ZnO-NPs showed high biopersistence in both seafood matrix (>100%). The biopersistence rates were higher than the recommended limit set by European Food Safety Authority (EFSA) (12%), referred to nanotechnologies to be applied in the food and feed chain, thus the investigated naturally occurring NPs cannot be considered readily degradable.

Cyclopropane fatty acids (CPFA), like dihydrosterculic and lactobacillic acid, are unusual fatty acids found in microorganisms, seed oils of some sub-tropical plants, and protozoa. Recently, these molecules were detected in milk and dairy products, as well as in meat and fish. To the best of our knowledge, only a few studies have documented their presence and relevance in animals and humans. In the present work, the digestibility of CPFA from Grana Padano cheese was evaluated through an in vitro digestion model. Two different complementary analytical techniques (1HNMR and GC-MS) were applied for better evaluating the presence of CPFA in raw and digested matrices. Results showed that CPFA were released from tri-O-acylglycerols, and that the cyclopropane ring was not degraded, indicating their stability and potential bioaccessibility after digestion in the present model. 1H NMR and GC-MS analysis of the digested samples also provided comprehensive and complementary information for studying qualitatively and quantitatively the hydrolysis level of these fatty acids in complex lipid matrices.

A total of 17 (poly)phenolic compounds have been quantified in the free and bound fraction of raw, olive oil fried, sunflower oil fried and griddled cardoon (Cynara cardunculus L.). Caffeoylquinic acid derivatives (CQAs), particularly 5-CQA, were the major compounds. The bioaccessibility of (poly)phenols after gastrointestinal digestion and fecal fermentation (24 h) was studied. Heat treatment exerted a positive effect on the bioaccessibility of (poly)phenols. In raw cardoon, only 2% of the total amount of (poly)phenolic compounds was still bioaccessible after gastrointestinal digestion, while in cooked cardoon samples, between 60 and 67% of the total amount of (poly)phenolic compounds remained unmodified. An important microbial metabolic activity was observed during the fecal fermentation, which resulted in a complete degradation of CQAs after 5 h and in the formation of different catabolites. 3-(3′-hydroxyphenyl)propionic acid was by far the most abundant catabolite produced. Catabolic pathways for colonic microbial degradation of CQAs of cardoon have been proposed.

A total of 21 (poly)phenolic compounds (free and bound) were quantified in raw, olive oil fried, sunflower oil fried and griddled green pepper before and after a simulated gastrointestinal digestion. Flavonoids, particularly quercetin rhamnoside, were the main compounds. The bioaccessibility of (poly)phenolic compounds after gastrointestinal digestion was higher in cooked (>82%) than in raw (48%) samples, showing a positive effect of heat treatment on the release of (poly)phenols from the vegetal matrix. Additionally, a faecal fermentation was carried out for 24h. A time-dependent microbial metabolic activity was observed, which resulted firstly (<5h) in the hydrolysis of flavonoid glycosides and then in the formation of 3 catabolites, namely 3,4-dihydroxybenzoic acid, dihydrocaffeic acid and 3-(3′-hydroxyphenyl)propionic acid, this being by far the most abundant. Catabolic pathways for colonic microbial degradation of flavonoids and hydroxycinnamic acids have been proposed. Griddled pepper showed the highest amount of (poly)phenols both after gastrointestinal digestion and colonic fermentation.