Changes in bio-accessibility, polyphenol profile and antioxidants of quinoa and djulis sprouts during in vitro simulated gastrointestinal digestion

In vitro simulated saliva, gastric, and intestinal digestion followed by faecal fermentation reveals a potential modulatory activity of Epimedium on human gut microbiota

Herba Epimedii, known for its rich array of bioactive ingredients and widespread use in ethnopharmacological practices, still lacks a comprehensive understanding of its gastrointestinal biotransformation. In this study, we qualitatively explored the dynamic changes in Epimedium sagittatum components during in vitro simulated digestions, with a quantitative focus on its five major flavonoids. Notably, significant metabolism of E. sagittatum constituents occurred in the simulated small intestinal fluid and colonic fermentation stages, yielding various low molecular weight metabolites. Flavonoids like kaempferol glycosides were fully metabolized in the simulated intestinal fluid, while hyperoside digestion occurred during simulated colon digestion. Colonic fermentation led to the production of two known bioactive isoflavones, genistein, and daidzein. The content and bioaccessibility of the five major epimedium flavonoids-icariin, epimedin A, epimedin B, epimedin C, and baohuoside I-significantly increased after intestinal digestion. During colon fermentation, these components gradually decreased but remained incompletely metabolized after 72 h. Faecal samples after E. sagittatum fermentation exhibited shift towards dominance by Lactobacillus (Firmicutes), Bifidobacterium (Actinobacteria), Streptococcus (Firmicutes), and Dialister (Firmicutes). These findings enhance our comprehension of diverse stages of Herba Epimedii constituents in the gut, suggesting that the primary constituents become bioaccessible in the colon, where new bioactive compounds may emerge.

Metabolomic insights into the profile, bioaccessibility, and transepithelial transport of polyphenols from germinated quinoa during in vitro gastrointestinal digestion/Caco-2 cell transport, and their prebiotic effects during colonic fermentation

The health-promoting activities of polyphenols and their metabolites originating from germinated quinoa (GQ) are closely related to their digestive behavior, absorption, and colonic fermentation; however, limited knowledge regarding these properties hinder further development. The aim of this study was to provide metabolomic insights into the profile, bioaccessibility, and transepithelial transport of polyphenols from germinated quinoa during in vitro gastrointestinal digestion and Caco-2 cell transport, whilst also investigating the changes in the major polyphenol metabolites and the effects of prebiotics during colonic fermentation. It was found that germination treatment increased the polyphenol content of quinoa by 21.91%. Compared with RQ group, 23 phenolic differential metabolites were upregulated and 47 phenolic differential metabolites were downregulated in GQ group. Compared with RQ group after simulated digestion, 7 kinds of phenolic differential metabolites were upregulated and 17 kinds of phenolic differential metabolites were downregulated in GQ group. Compared with RQ group after cell transport, 7 kinds of phenolic differential metabolites were upregulated and 9 kinds of phenolic differential metabolites were downregulated in GQ group. In addition, GQ improved the bioaccessibilities and transport rates of various polyphenol metabolites. During colonic fermentation, GQ group can also increase the content of SCFAs, reduce pH value, and adjust gut microbial populations by increasing the abundance of Actinobacteria, Bacteroidetes, Verrucomicrobiota, and Spirochaeota at the phylum level, as well as Bifidobacterium, Megamonas, Bifidobacterium, Brevundimonas, and Bacteroides at the genus level. Furthermore, the GQ have significantly inhibited the activity of α-amylase and α-glucosidase. Based on these results, it was possible to elucidate the underlying mechanisms of polyphenol metabolism in GQ and highlight its beneficial effects on the gut microbiota.

Cereal sprout-based food products: Industrial application, novel extraction, consumer acceptance, antioxidant potential, sensory evaluation, and health perspective

Cereal grains are a good source of macronutrients and micronutrients that are required for metabolic activity in the human body. Sprouts have been studied to enhance the nutrient profile. Moreover, secondary metabolites are examined as green food engineering technology that is used in the pharmaceutical, functional ingredients, nutraceutical, and cosmetic industries. The sprout-based food is commonly used to enhance the quality of products by softening the structure of the whole grain and increasing the phytochemicals (nutritional value and bioactive compounds). These sprouting grains can be added to a variety of products including snacks, bakery, beverage, and meat. Consuming whole grains has been shown to reduce the incidence and mortality of a variety of chronic and noncommunicable diseases. Sprouting grains have a diversity of biological functions, including antidiabetic, antioxidant, and anticancer properties. Cereal sprout-based products are more beneficial in reducing the risk of cardiovascular diseases and gastrointestinal tract diseases. The novel extraction techniques (microwave-existed extraction, pulse electric field, and enzyme-associated) are applied to maintain and ensure the efficiency, safety, and nutritional profile of sprout. Nutrient-dense sprouts have a low environmental impact and are widely accepted by consumers. This review explores for the first time and sheds light on the antioxidant potential, sensory evaluation, industrial applications, and health perspective of cereal sprout-based food products.

Nutritional composition of quinoa leafy greens: An underutilized plant-based food with the potential of contributing to current dietary trends

Quinoa (Chenopodium quinoa Willd.) leafy greens (QLGs) are plant-based foods of high nutritional value that have been scarcely studied. In this work, the nutritional and functional composition of three QLGs varieties was evaluated. A protein content higher than 35 g 100 g-1 dw with a well-balanced essential amino acid composition was found making them a good source of vegetable protein. In addition, elevated contents of dietary fibre and minerals, higher than those detected in quinoa seeds and other leafy vegetables, were found. The lipid profile showed higher contents of linoleic (C18:2, ω6) (20.2 %) and linolenic acids (C18:3, ω3) (52.8 %) with low ω6/ ω3 ratios (∼0.4/1). A total sugar content <1 g 100 g-1 dw was found for all varieties tested, lower than that obtained in seeds. The saponin content varied between 0.76 and 0.87 %. Also, high values of total phenolic compounds (969.8-1195.4 mg gallic acid 100 g-1), mainly hydroxycinnamic acids and flavonoids, and great antioxidant activities (7.64-8.90 g Trolox kg-1) were found. Multivariate analysis here used allowed us to classify the samples according to the quinoa variety evaluated, and the sequential stepwise multiple regression applied revealed that the PUFA and sucrose contents negatively influenced the protein content while the palmitic acid content affected positively this parameter. Overall, this study shows that QLGs are promising nutritious and functional plant-based foods supporting the necessity of promoting their cultivation, commercialization, and consumption.

Nutrient composition, functional activity and industrial applications of quinoa (Chenopodium quinoa Willd.)

Quinoa is one of the gluten-free crops that has attracted considerable interest. Quinoa contains functional ingredients such as bioactive peptides, polysaccharides, saponins, polyphenols, flavonoids and other compounds. It is very important to determine efficient methods to identify such functional ingredients, and to explain their possible health benefits in humans. In this review, the chemical structure and biological activity mechanisms of quinoa nutrient composition have been elaborated. In addition, the development of quinoa-based functional foods and feed is emerging, providing a reference for the development of functional products with quinoa as an ingredient that are beneficial to health. The active ingredients in quinoa have different health effects including antioxidant, antidiabetic, antihypertensive, anti-inflammatory, and anti-obesity activities. Further exploration is also needed to improve the application of quinoa within the functional food industry, and in the areas of feed, medicine and cosmetics.

Physicochemical Properties, Antioxidant Capacity, and Bioavailability of Laurus nobilis L. Leaf Polyphenolic Extracts Microencapsulated by Spray Drying

Laurel (Laurus nobilis L.) leaves are a rich source of polyphenols with the potential for use in functional foods, where the main obstacle is their low stability and bioavailability, which can be improved by spray drying (SD). This research examined the influence of SD parameters, including inlet temperature (120, 150, and 180 °C), carrier type (β-cyclodextrin (β-CD); β-CD + maltodextrin (MD) 50:50; β-CD + gum arabic (GA) 50:50), and sample:carrier ratio (1:1, 1:2 and 1:3) on the physicochemical properties, encapsulation efficiency, polyphenolic profile, antioxidant capacity and bioaccessibility of laurel leaf polyphenols. The highest encapsulation efficiency was achieved at a sample:carrier ratio 1:2 and the temperature of 180 °C by using either of the applied carriers. However, the application of β-CD + MD 50:50 ensured optimal solubility (55.10%), hygroscopicity (15.32%), and antioxidant capacity (ORAC 157.92 μmol Trolox equivalents per g of powder), while optimal moisture content (3.22%) was determined only by temperature, demanding conditions above 150 °C. A total of 29 polyphenols (dominantly flavonols) were identified in the obtained powders. SD encapsulation increased the bioaccessibility of laurel flavonols in comparison to the non-encapsulated extract by ~50% in the gastric and ~10% in the intestinal phase, especially for those powders produced with carrier mixtures.

Effect of Hot- and Cold-Water Treatment on Broccoli Bioactive Compounds, Oxidative Stress Parameters and Biological Effects of Their Extracts

The goal of this work was to define resistant and susceptible variables of young broccoli (Brassica oleracea L. convar. botrytis (L.) Alef. var. cymosa Duch.) plants treated with cold and hot water. Additionally, we wanted to single out variables that could potentially be used as biomarkers of cold/hot-water stress in broccoli. Hot water changed more variables (72%) of young broccoli than cold water (24%) treatment. Hot water increased the concentration of vitamin C for 33%, hydrogen peroxide for 10%, malondialdehyde for 28%, and proline for 147%. Extracts of broccoli stressed with hot water were significantly more efficient in the inhibition of α-glucosidase (65.85 ± 4.85% compared to 52.00 ± 5.16% of control plants), while those of cold-water-stressed broccoli were more efficient in the inhibition of α-amylase (19.85 ± 2.70% compared to 13.26 ± 2.36% of control plants). Total glucosinolates and soluble sugars were affected by hot and cold water in an opposite way, which is why they could be used as biomarkers of hot/cold-water stress in broccoli. The possibility of using temperature stress to grow broccoli enriched with compounds of interest to human health should be further investigated.

Metabolomics analysis reveals the accumulation patterns of flavonoids and phenolic acids in quinoa (Chenopodium quinoa Willd.) grains of different colors

Quinoa grains are gaining increasing popularity owing to their high nutritional merits. However, only limited information is available on the metabolic profiles of quinoa grains. In this study, we determined the metabolic profiles of black, red, and white quinoa grains via an ultraperformance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS)-based metabolomics. A total of 689 metabolites were identified, among which 251, 182, and 317 metabolites displayed different accumulation patterns in the three comparison groups (Black vs Red, Black vs White, and Red vs White), respectively. In particular, flavonoid and phenolic acid contents displayed considerable differences, with 22 flavonoids, 5 phenolic acids, and 1 betacyanin being differentially accumulated among the three quinoa cultivars. Additionally, correlation analysis showed that flavonoids and phenolic acids could act as betanin co-pigments in quinoa grains. In conclusion, this study provides comprehensive insights into the adequate utilization and development of novel quinoa-based functional foods.

Biological activity of extracts and hydrolysates from early- and adult-stage edible grasshopper Sphenarium purpurascens

Edible insects have become a promising food source because they are rich in protein, fatty acids, minerals, among others. In recent years, edible insects have been proposed to be used as innovative functional ingredients in terms of biological activity. The present study aimed to determine and compare biological activities of the extracts and hydrolysates obtained from early- and adult-stage edible grasshoppers Sphenarium purpurascens to evaluate their potential as a source of bioactive compounds. Proximal analyses showed that in adult grasshoppers (AGs), the percentage of protein (48.9% ± 1.2), crude fat (13.1% ± 0.09), and chitin (15.6% ± 0.81) was significantly higher than early grasshoppers (EGs) (42.2% ± 0.55, 9.35% ± 0.08, and 10.5% ± 0.15, respectively). Total phenolic compounds, 2,2-diphenyl-1-picrylhydrazyl (DPPH•), and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS•+) free radical scavenging were analyzed and reported. Enzymatic hydrolysis increased the concentration of total phenolic compounds and higher antioxidant capacity (up to 252.78 mM trolox). Once fractionated by ultrafiltration, the fraction that presented the highest antioxidant activity against DPPH• and ABTS•+ was that with molecules ≤ 10 kDa. Furthermore, the bioaccessibility of the samples was analyzed by in vitro protein digestion using a multienzymatic method, and a recovery index (RI) was reported. Extracts and hydrolysates were analyzed by UPLC-MS, and this allowed the identification of phenolic acids and flavonoids. The results obtained in this work suggest that the grasshopper can be used as a possible source of bioactive compounds that can be used in the food or pharmaceutical industry.

Development of Functional Fermented Dairy Products Containing Taiwan Djulis (Chenopodium formosanum Koidz.) in Regulating Glucose Utilization

Taiwan djulis (Chenopodium formosanum Koidz.) is a plant native to Taiwan and is a grain rich in nutrients, vitamins, and minerals with antioxidant properties. This paper aimed to use appropriate processing technology and incorporate probiotics, thus combining Taiwan’s high-quality milk sources to develop Taiwan djulis fermented dairy products. Later, FL83B cells have used to evaluate the glucose utilization ability after the administration of djulis. We first screened Lactiplantibacillus plantarum and combined it with the traditional yogurt strains Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus for cultivation. Further, the fermentation process was optimized where 7.5% djulis and an inoculum of 107 colony forming unit/mL were fermented at 40 °C for 18 h. Compared to fermented milk without djulis, the analysis of various nutrients and active ingredients showed that free radical scavenging abilities of DPPH and ABTS reached 2.3 and 2.0 times (752.35 ± 29.29 µg and 771.52 ± 3.79 µg TE/g, respectively). The free phenol content increased 2.5 times (169.90 ± 14.59 mg gallic acid/g); the total flavonoid content enhanced 4.8 times (3.05 ± 0.03 mg quercetin/g), and the gamma-aminobutyric acid content was 3.07 ± 0.94 mg/g. In a co-culture of mouse liver cells with fermented products, 100 ppm ethanol extract of fermented products effectively improved glucose utilization with increased glucose transporter expression. This functional fermented dairy product can be developed into the high value added local agricultural products and enhance multiple applications including medical and therapeutic fields.

Changes in Phenolic Compound and Antioxidant Activity of Germinated Broccoli, Wheat, and Lentils during Simulated Gastrointestinal Digestion

The consumption of sprouts has increased as the germination process causes changes in the chemical composition of the seeds, improving their nutritional value. The aim of this work was to compare the total phenolic content and antioxidant capacity of broccoli, lentils and wheat sprouts before and after in vitro digestion, and the total phenolic content and antioxidant capacity between seeds and sprouts. Broccoli and wheat showed no difference in total phenolic content before and after germination, while lentils showed a significant decrease in total phenolic content after germination. The antioxidant capacity of broccoli and wheat increased after germination. After simulated digestion, the total phenolic content and antioxidant activity of broccoli sprouts significantly decreased during digestion in the gastric phase compared to the sprouts before digestion. Lentil sprouts did not show a decrease in total phenolic content during the gastric phase of digestion compared to the sprouts before digestion. However, they showed a significant increase in total phenolic content during the enteric phase. Finally, wheat sprouts showed a significant increase in total phenolic content and antioxidant activity during the gastric phase of digestion compared to grain before digestion. The germination process may increase the antioxidant capacity of sprouts, although this is not always related to the phenolic compound.

Antioxidant and anti-obesity effects of in vitro digesta of germinated buckwheat

Buckwheat germinated on days of 3, 5, and 7 was digested in vitro, and the antioxidant and anti-obesity effects of the digesta were evaluated. In vitro digesta of 5 days germinated buckwheat (GBD5) showed significantly higher antioxidant activity in DPPH, ABTS, total phenolic content, total flavonoid content, and ferric reducing antioxidant power by 5.3, 1.3, 2.0, 3.2, and 2.8-fold, respectively than in vitro digesta of non-germinated buckwheat. GBD5 exerted inhibitory effect on total lipid accumulation in 3T3-L1 adipocyte in a dose-dependent manner, with over 25% reduction at 400 µg/mL. Additionally, GBD5 significantly downregulated genes related to adipocyte differentiation and fat accumulation. GBD5 possessed different metabolite profiles compared to others such as higher content of γ-aminobutyric acid and succinic acid. Therefore, GBD5 has potent antioxidant effects and suppresses fat accumulation-related genes and proteins expression, which could act as a new functional substance.

Nutritional Composition and Bioactive Components in Quinoa (Chenopodium quinoa Willd.) Greens: A Review

Quinoa (Chenopodium quinoa Willd.) is a nutrient-rich grain native to South America and eaten worldwide as a healthy food, sometimes even referred to as a ”superfood”. Like quinoa grains, quinoa greens (green leaves, sprouts, and microgreens) are also rich in nutrients and have health promoting properties such as being antimicrobial, anticancer, antidiabetic, antioxidant, antiobesity, and cardio-beneficial. Quinoa greens are gluten-free and provide an excellent source of protein, amino acids, essential minerals, and omega-3 fatty acids. Quinoa greens represent a promising value-added vegetable that could resolve malnutrition problems and contribute to food and nutritional security. The greens can be grown year-round (in the field, high tunnel, and greenhouse) and have short growth durations. In addition, quinoa is salt-, drought-, and cold-tolerant and requires little fertilizer and water to grow. Nevertheless, consumption of quinoa greens as leafy vegetables is uncommon. To date, only a few researchers have investigated the nutritional properties, phytochemical composition, and human health benefits of quinoa greens. We undertook a comprehensive review of the literature on quinoa greens to explore their nutritional and functional significance to human health and to bring awareness to their use in human diets.

Phenolic compound profile of probiotic (Lacticaseibacillus rhamnosus LR5) fortified vegetable tablet and probiotic survival in the simulated gastrointestinal tract

The objectives of this research were to study the changes of phenolic compounds in vegetable (yellow VS green) tablets with/without probiotics (Lacticaseibacillus rhamnosus LR5) supplementation by using high performance liquid chromatography and probiotic survivability through the simulated gastrointestinal tract. The green vegetable tablets with/without probiotics had a greater (p ≤ 0.05) phenolic content compared to the yellow ones. There were no significant differences of most phenolic compound contents between probiotic-supplemented vegetable tablets and non-probiotic supplemented ones (p > 0.05). The contents of ferulic acid, epicatechin, tannic acid and rutin for both vegetable tablets tended to decrease through passing the stomach (1 and 2 h) and small intestine (2 and 4 h), however, the content of catechin in the yellow vegetable tablets tended to increase. The results also showed that the survival of Lacticaseibacillus rhamnosus LR5 slightly decreased through the simulated gastrointestinal tract. The vibrations from FTIR appeared in the wave length of 4000–3100, 3000–2800 and 1652–1545 cm⁻¹, which accounted for the change in the N–H bonds of the amine group, changes in the structure of fatty acids and the change of carbonyl groups, respectively. This work highlighted the opportunity of application of probiotics in food products; especially non-dairy foods for consumer with dairy allergy.

Influence of Elicitation and Drying Methods on Anti-Metabolic Syndrome, and Antimicrobial Properties of Extracts and Hydrolysates Obtained from Elicited Lovage (Levisticum officinale Koch)

This research aims to investigate the influence of elicitation and drying methods (natural, convection, microwave, and freeze-drying), with jasmonic acid (JA) and yeast extract (YE) on the biological activity of extracts and hydrolysates from lovage (Levisticum officinale Koch) leaves. The results indicate that the highest TPC was determined for hydrolysates obtained from JA-elicited microwave-dried lovage (24.96 mg/gDW). The highest ACE and lipase inhibitory activity was noted for PBS extract obtained from JA-elicited lovage after microwave drying (EC₅₀ = 0.16 and 0.12 mg/mL, respectively). Ethanolic extract from JA-elicited lovage after freeze-drying was characterized by the highest α-amylase inhibitory activity (EC₅₀ = 3.92 mg/mL) and the highest α-glucosidase inhibitory activity (EC₅₀ = 1.43 mg/mL) was noted for hydrolysates from control plants subjected to freeze-drying. The highest antimicrobial activity towards C. albicans yeasts was observed for microwave ethanolic extracts with minimal inhibition (MIC) and lethal (MLC) concentrations of 0.625 and 1.25 mg/mL, respectively.

Biomolecules with Antioxidant Capacity from the Seeds and Sprouts of 20 Varieties of Chenopodium quinoa Willd. (Quinoa)

Quinoa has acquired a great interest due to its high content of nutrients and biomolecules that have nutritional and medicinal properties. The aim of this study was to compare the total phenolic content (TPC), total flavonoids (TF), and the antioxidant capacity of 20 varieties of seeds and sprouts of quinoa extract. Quinoa seeds were germinated for 72 h and dried in an oven at 45 °C. The extracts were obtained by dynamic extraction using methanol. Phytochemical analysis with liquid chromatography coupled with mass spectrometry (LC-ESI-MS/MS), TPC, TF, and the antioxidant capacity was carried out and compared between both extracts. The TPC was determined with Folin-Ciocalteu reagent, TF with AlCl₃, and the antioxidant capacity was determined according to the DPPH and ABTS assays. Sprout extracts showed high values of TPC (31.28 ± 0.42 mg GAE/g; Pasankalla variety), TF (14.31 ± 0.50 mg EQ/g; black Coito variety), and antioxidant capacity (IC_{50 (DPPH)}: 12.69 ± 0.29 µg/mL and IC_{50 (ABTS):} 3.51 ± 0.04 µg/mL; Pasankalla). The extracts of the Pasankalla variety revealed 93 and 90 phytochemical constituents in the seeds and sprouts, respectively, such as amino acids, phenolic acids, flavonoids, fatty acids, and triterpene saponins, among others. Quinoa sprouts showed a high content of TPC and TF, and high antioxidant capacity compared with seed extracts, especially the Pasankalla variety.

Botany, Nutritional Value, Phytochemical Composition and Biological Activities of Quinoa

Quinoa is a climate-resilient food grain crop that has gained significant importance in the last few years due to its nutritional composition, phytochemical properties and associated health benefits. Quinoa grain is enriched in amino acids, fiber, minerals, phenolics, saponins, phytosterols and vitamins. Quinoa possesses different human-health promoting biological substances and nutraceutical molecules. This review synthesizes and summarizes recent findings regarding the nutrition and phytochemical properties of quinoa grains and discusses the associated biological mechanisms. Quinoa grains and grain-based supplements are useful in treating different biological disorders of the human body. Quinoa is being promoted as an exceptionally healthy food and a gluten-free super grain. Quinoa could be used as a biomedicine due to the presence of functional compounds that may help to prevent various chronic diseases. Future research needs to explore the nutraceutical and pharmaceutical aspects of quinoa that might help to control different chronic diseases and to promote human health.

Bioaccessibility of phenolic acids in Canadian hulless barley varieties

In order to gain understanding of bioaccessibility of phenolic acids in food-grade barley, an investigation was conducted using four cooked whole-grain, hulless, barley varieties. An in vitro digestion model was used to mimic human upper gastrointestinal digestion. Boiling enhanced the extractability of bound phenolic acids while digestion increased the level of free phenolic acids. The high bioaccessibilities observed were likely due to the release of bound phenolic acids during cooking and digestion. The major bioaccessible phenolics were ferulic and p-coumaric acids with bioaccessibility ranging from 131 to 173% and 51-135%, respectively. Peru-35 had significantly greater bioaccessibility of ferulic acid compared to other varieties. A hydroxycinnamic acid amide not reported before in boiled barley, N¹, N⁸- dicaffeoyl spermidine, was identified in free phenolic extracts with relatively high abundance compared to the phenolic acids. It may provide additional anti-inflammatory and antioxidant functions. These cooked whole-grain, hulless barley varieties are sources of bioaccessible phenolic acids.

Cellular Antioxidant Activity of Olive Pomace Extracts: Impact of Gastrointestinal Digestion and Cyclodextrin Encapsulation

Olive pomace is a valuable secondary raw material rich in polyphenols, left behind after the production of olive oil. The present study investigated the protective effect of a polyphenolic extract from olive pomace (OPE) on cell viability and antioxidant defense of cultured human HepG2 cells submitted to oxidative stress induced by tert-butylhydroperoxide (tBOOH). The investigation considered possible matrix effects, impact of gastrointestinal digestion and cyclodextrin (CD) encapsulation. Pre-treatment of cells with OPE prevented cell damage and increased intracellular glutathione but did not affect the activity of glutathione peroxidase and superoxide dismutase. OPE matrix significantly enhanced cell protective effects of major antioxidants, such as hydroxytyrosol (HTS), while cyclodextrin encapsulation enhanced activity of OPE against intracellular reactive oxygen species (ROS) accumulation. The obtained results show that OPE is more potent antioxidant in comparison to equivalent dose of main polyphenols (HTS and TS) and that increasing solubility of OPE polyphenols by CD encapsulation or digestion enhances their potential to act as intracellular antioxidants. Antioxidative protection of cells by OPE was primarily achieved through direct radical-scavenging/reducing actions rather than activation of endogenous defense systems in the cell.

Quinoa as source of type 1 ribosome inactivating proteins: A novel knowledge for a revision of its consumption

This study investigates on the presence of toxic proteins in quinoa seeds. To this aim, a plethora of biochemical approaches were adopted for the purification and characterization of quinoin, a type 1 ribosome-inactivating protein (RIP) contained in quinoa seeds. We determined its melting temperature (68.2 ± 0.6 °C) and thermostability (loss of activity after 10-min incubation at 70 °C). Considering that quinoa seeds are used as a food, we found that quinoin is cytotoxic against BJ-5ta (human fibroblasts) and HaCaT (human keratinocytes) in a dose- and time-dependent manner. Moreover, in an in vitro digestive pepsin-trypsin treatment, 30% of quinoin is resistant to enzymatic cleavage. This toxin was found in seeds (0.23 mg/g of seeds) and in sprouted seeds obtained after 24-h (0.12 mg/g of sprout) and 48-h (0.09 mg/g of sprout). We suggest a thermal treatment of quinoa seeds before consumption in order to inactivate the toxin, particularly in sprouts, generally consumed raw.