ABSTRACT
BACKGROUND: The multifactorial origin of many chronic diseases provides a new framework for the development of multifunctional foods. In this study, the effect of in vitro simulated gastrointestinal digestion of kiwicha (Amaranthus caudatus) proteins on the release of multifunctional peptides was evaluated. RESULTS: Gastric digest showed higher angiotensin I converting enzyme (ACE) inhibitory activity while 60 min gastroduodenal digest showed the highest antioxidant, dipeptidyl peptidase IV (DPP-IV), α-amylase and Caco-2 cell viability inhibitory activities. Peptides >5 kDa were more effective in inhibiting colon cancer cell viability, whereas peptides <5 kDa were mainly responsible for the antioxidant, ACE, DPP-IV and α-amylase inhibitory activities. Thirteen peptides from amaranth sequenced proteins were identified. Structure-activity relationship analysis of the identified sequences pointed to three amaranth fragments, namely FLISCLL, SVFDEELS and DFIILE, as potential peptides able to concurrently exert antioxidant capacity and ability to inhibit both ACE and α-amylase. CONCLUSIONS: Five of thirteen peptides identified in kiwicha protein digests show high potential to exert multifunctional properties. Thus kiwicha proteins might start to gain importance as ingredients for functional foods for the prevention and/or management of chronic diseases related to oxidative stress, hypertension and/or diabetes. © 2018 Society of Chemical Industry.
Subject(s)
Amaranthus/chemistry , Dipeptidyl-Peptidase IV Inhibitors/chemistry , Gastrointestinal Tract/metabolism , Peptides/chemistry , Plant Extracts/chemistry , Plant Proteins/chemistry , Caco-2 Cells , Digestion , Dipeptidyl Peptidase 4/chemistry , Dipeptidyl-Peptidase IV Inhibitors/isolation & purification , Humans , Kinetics , Peptide Mapping , Peptides/isolation & purification , Plant Extracts/isolation & purification , Protein Hydrolysates/chemistry , alpha-Amylases/antagonists & inhibitors , alpha-Amylases/chemistryABSTRACT
The impact of the naturally present phenolic compounds and/or proteins on the antioxidant capacity of flaxseed products (phenolic fraction, protein concentrates, and hydrolysates) before and after simulated gastrointestinal digestion was studied. For that, whole and phenolic reduced products were assessed. Four glycosylated phenolic compounds (secoisolariciresinol and ferulic, p-coumaric, and caffeic acids) were identified in flaxseed products. Phenolic fraction exerts the highest antioxidant capacity that increased by alkaline hydrolysis and by simulated gastrointestinal digestion. The action of Alcalase and digestive enzymes resulted in an increase of the antioxidant capacity of whole and phenolic reduced products. Principal component analysis showed that proteinaceous samples act as antioxidant is by H+ transfer, while those samples containing phenolic compounds exert their effects by both electron donation and H+ transfer mechanisms. Protein/peptide-phenolic complexation, confirmed by fluorescence spectra, exerted a positive effect on the antioxidant capacity, mainly in protein concentrates.
Subject(s)
Antioxidants/chemistry , Flax/chemistry , Phenols/chemistry , Plant Extracts/chemistry , Plant Proteins/chemistry , Seeds/chemistry , Antioxidants/metabolism , Flax/metabolism , Gastrointestinal Tract/metabolism , Humans , Hydrolysis , Mass Spectrometry , Models, Biological , Phenols/metabolism , Plant Extracts/metabolism , Plant Proteins/metabolism , Seeds/metabolismABSTRACT
ALIBIRD, a test substance composed of oligosaccharides derived from lactulose, a hydrolysate of a whey protein concentrate, and a supercritical extract of rosemary (1:0.5:0.05), was prepared in the laboratory and evaluated for its safety as a multifunctional food additive. In oral toxicity studies (acute and 28 days repeated dose) using Wistar rats, ALIBIRD was administered in a single oral gavage dose of 2,000 mg/kg of body weight and resulted in no adverse events or mortality; a daily dose of 2,000 mg/kg of body weight for 28 days by gavage also resulted in no adverse effects or mortality. No abnormal clinical signs, behavioral changes, body weight changes, or changes in food and water consumption occurred in either study. There were no changes in hematological and serum chemistry values, organ weights, or gross or histological characteristics. Based on test results, it is concluded that ALIBIRD is well tolerated in rats at an acute and subchronic (28 days) dose of 2,000 mg/kg of body weight.
Subject(s)
Plant Extracts/toxicity , Rosmarinus/chemistry , Administration, Oral , Animals , Body Weight/drug effects , Dose-Response Relationship, Drug , Models, Animal , Plant Extracts/administration & dosage , Rats , Rats, WistarABSTRACT
A colorimetric method previously described for the determination of chitosan has been evaluated because lack of linearity had been observed at certain concentrations. Calibration curves of varied-characteristic chitosans, recovery studies and chitosan quantification in seven commercial dietary supplements have been performed. Some analysis conditions including the solvent of the samples have been studied and optimised. Different data combinations have been checked in order to select the widest range of concentrations where no serial correlation was found. With the selected conditions the method is linear, reproducible and provides reliable results in the analysis of the chitosan content in capsules. Its selectivity has been proved by the lack of interference with other compounds present in the dietary supplements. But in the case of tablet products, the presence of cellulose and magnesium stearate may produce an underestimation of the chitosan content.