A multi-centre peptidomics investigation of food digesta: current state of the art in mass spectrometry analysis and data visualisation.

Mass spectrometry has become the technique of choice for the assessment of a high variety of molecules in complex food matrices. It is best suited for monitoring the evolution of digestive processes in vivo and in vitro. However, considering the variety of equipment available in different laboratories and the diversity of sample preparation methods, instrumental settings for data acquisition, statistical evaluations, and interpretations of results, it is difficult to predict a priori the ideal parameters for optimal results. The present work addressed this uncertainty by executing an inter-laboratory study with samples collected during in vitro digestion and presenting an overview of the state-of-the-art mass spectrometry applications and analytical capabilities available for studying food digestion. Three representative high-protein foods - skim milk powder (SMP), cooked chicken breast and tofu - were digested according to the static INFOGEST protocol with sample collection at five different time points during gastric and intestinal digestion. Ten laboratories analysed all digesta with their in-house equipment and applying theirconventional workflow. The compiled results demonstrate in general, that soy proteins had a slower gastric digestion and the presence of longer peptide sequences in the intestinal phase compared to SMP or chicken proteins, suggesting a higher resistance to the digestion of soy proteins. Differences in results among the various laboratories were attributed more to the peptide selection criteria than to the individual analytical platforms. Overall, the combination of mass spectrometry techniques with suitable methodological and statistical approaches is adequate for contributing to the characterisation of the recently defined digestome.

In vitro digestibility of goat milk and kefir with a new standardised static digestion method (INFOGEST cost action) and bioactivities of the resultant peptides.

The hydrolysis degrees of goat milk and kefir during simulated gastrointestinal digestion and some bioactivities of the resulting peptides after fermentation and digestion were studied. A static in vitro digestion method by the COST FA1005 Action INFOGEST was used and goat milk and kefir were partially hydrolyzed during the gastric phase and had above 80% hydrolysis after duodenal digestion. There were no differences between the digestibility of goat milk and kefir (p > 0.05). Goat milk and kefir displayed about 7-fold antioxidant activity after digestion (p < 0.05). Fermentation showed no effect on the calcium-binding capacity of the samples (p > 0.05), however, after in vitro digestion calcium-binding capacity of the goat milk and kefir increased 2 and 5 fold, respectively (p < 0.05). Digested goat milk and kefir showed a higher dose-dependent inhibitory effect on α-amylase compared to undigested samples (p < 0.05). α-Glucosidase inhibitory activities and in vitro bile acid-binding capacities of the samples were not determined at the studied concentrations.

In vitro starch digestibility, estimated glycemic index and antioxidant potential of taro (Colocasia esculenta L. Schott) corm.

The purpose of this study was to determine some functional properties of taro (Colocasia esculenta L. Schott) corm, which can be a good alternative to the other dietary carbohydrate sources with its high starch content. The total phenolic and flavonoid content of taro corm was found as 205±53mgCAE/100g and 61±9mgCAE/100g, respectively. The antioxidant capacity of corm was determined as 452±72mMTEAC/100g and 244±73mMTEAC/100g, by the scavenging activity against ABTS and DPPH radicals, respectively. The free glucose content of corms was less than 1%, whereas the 60% of dry matter was composed of starch. According to the results, the taro corms' starch was highly digestible and higher than the 50% of the starch was composed of rapidly digestible starch (RDS) fractions. The estimated glycemic index (eGI) of taro corm was 63.1±2.5, indicating taro corm as a medium GI food and a good dietary carbohydrate alternative especially for diabetic people.