Quinoa flavonoids and their bioaccessibility during in vitro gastrointestinal digestion

Comment on the "Does saponin in quinoa really embody the source of its bitterness?"

Saponins are considered the main source of the bitter taste of quinoa, however, it has not been confirmed by Song et al. (2024). These authors suggested that saponin extracts contribute to the umami taste, however, the stronger source of the bitter taste may be the flavonoids contained in the extracts. It is an interesting finding in view of the flavonoids role in the field of food sciences. The UPLC-MS results showed that besides saponins, also polyphenols were present in the analyzed samples. However, the presented results of UPLC-MS analysis should be substantially improved, mainly with respect to the reported accurate masses and retention times, as described in details in this comment.

Key phytochemicals contributing to the bitterness of quinoa

Despite its nutritional components and potential health benefits, the bitterness of quinoa seed limits its utilization in the food industry. Saponins are believed to be the main cause of the bitterness, but it is still uncertain which specific compound is responsible. This study aimed to isolate the main components contributing to the bitterness in quinoa seed by solvent extraction and various column chromatography techniques guided by sensory evaluation. Five compounds were identified by mass spectrometry and nuclear magnetic resonance analyses, with the dose-over-threshold factors from 29.03 to 198.89. The results confirmed that triterpenoids are responsible for the bitter taste in quinoa seed, with phytolaccagenic acid derivatives being the primary contributor. Additionally, kaempferol 3-O-(2″, 6″-di-O-α-rhamnopyranosyl)-β-galactopyranoside (namely mauritianin), was demonstrated for the first time to be associated with the bitterness of quinoa. This study could provide new insight into the bitter compound identification in quinoa.

Harnessing the Potential of Quinoa: Nutritional Profiling, Bioactive Components, and Implications for Health Promotion

Quinoa, a globally cultivated "golden grain" belonging to Chenopodium in the Amaranthaceae family, is recognized for being gluten-free, with a balanced amino acid profile and multiple bioactive components, including peptides, polysaccharides, polyphenols, and saponins. The bioactive compounds extracted from quinoa offer multifaceted health benefits, including antioxidative, anti-inflammatory, antimicrobial, cardiovascular disease (CVD) improvement, gut microbiota regulation, and anti-cancer effects. This review aims to intricately outline quinoa's nutritional value, functional components, and physiological benefits. Importantly, we comprehensively provide conclusions on the effects and mechanisms of these quinoa-derived bioactive components on multiple cancer types, revealing the potential of quinoa seeds as promising and effective anti-cancer agents. Furthermore, the health-promoting role of quinoa in modulating gut microbiota, maintaining gut homeostasis, and protecting intestinal integrity was specifically emphasized. Finally, we provided a forward-looking description of the opportunities and challenges for the future exploration of quinoa. However, in-depth studies of molecular targets and clinical trials are warranted to fully understand the bioavailability and therapeutic application of quinoa-derived compounds, especially in cancer treatment and gut microbiota regulation. This review sheds light on the prospect of developing dietary quinoa into functional foods or drugs to prevent and manage human diseases.

A View on the Chemical and Biological Attributes of Five Edible Fruits after Finishing Their Shelf Life: Studies on Caco-2 Cells

We studied five common perishable fruits in terms of their polyphenols dynamic, minerals distribution, scavenger activity and the effects of 50% ethanolic extracts on the viability of Caco-2 cells in vitro, over a period of time between T = 0 and T = 5/7 days, typically the end of their shelf life. Altogether, there were few changes found, consisting of either an increase or a decrease in their chemical and biological attributes. A slow decrease was found in the antioxidant activity in apricot (-11%), plum (-6%) and strawberry (-4%) extracts, while cherry and green seedless table grape extracts gained 7% and 2% antioxidant potency, respectively; IC50 values ranged from 1.67 to 5.93 μg GAE/μL test extract. The cytotoxicity MTS assay at 24 h revealed the ability of all 50% ethanol fruit extracts to inhibit the Caco-2 cell viability; the inhibitory effects ranged from 49% to 83% and were measured at 28 µg GAE for strawberry extracts/EES, from 22 µg to 45 µg GAE for cherry extracts/EEC, from 7.58 to 15.16 µg GAE for apricot extracts/EEA, from 12.50 to 25.70 µg GAE for plum extracts/EEP and from 21.51 to 28.68 µg GAE for green table grape extracts/EEG. The MTS anti-proliferative assay (72 h) also revealed a stimulatory potency upon the Caco-2 viability, from 34% (EEA, EEG) and 48% (EEC) to 350% (EES) and 690% (EEP); therefore fruit juices can influence intestinal tumorigenesis in humans.

The Effect of Opuntia ficus Mucilage Pectin and Citrus aurantium Extract Added to a Food Matrix on the Gut Microbiota of Lean Humans and Humans with Obesity

Experimental studies have provided evidence that physicochemical interactions in the food matrix can modify the biologically beneficial effects of bioactive compounds, including their effect on gut microbiota. This work aimed to evaluate the effect of a food gel matrix with Opuntia ficus cladodes mucilage pectin and Citrus Aurantium extract on the growth of four beneficial gut bacteria obtained from the fecal microbiota of people who are lean or who have obesity after digestion in the upper digestive system. To accomplish this, a base formulation of Opuntia ficus cladodes mucilage with or without C. aurantium extract was submitted to an ex vivo fecal fermentation in an automatic and robotic intestinal system. The changes in the intestinal microbiota were determined by means of plate culture and 16S sequencing, while short-chain fatty acids (SCFA) produced in the colon were determined via gas chromatography. In the presence of the extract in formulation, greater growth of Bifidobacterium spp. (+1.6 Log10 Colonic Forming Unit, UFC) and Lactobacillus spp. (+2 Log10 UFC) in the microbiota of lean people was observed. Only the growth in Salmonella spp. (-1 Log10 UFC) from both microbiota was affected in the presence of the extract, which decreased in the ascending colon. SCFA was mainly produced by the microbiota of people who were lean rather than those who had obesity in the presence of the extract, particularly in the ascending colon. The effect of sour orange extract seems to depend on the origin of the microbiota, whether in people who have obesity (25 mM/L) or are lean (39 mM/L).

Effect of Germination on the Physicochemical Properties, Functional Groups, Content of Bioactive Compounds, and Antioxidant Capacity of Different Varieties of Quinoa (Chenopodium quinoa Willd.) Grown in the High Andean Zone of Peru

Germination is an effective strategy to improve the nutritional and functional quality of Andean grains such as quinoa (Chenopodium quinoa Willd.); it helps reduce anti-nutritional components and enhance the digestibility and sensory aspects of the germinated. This work aimed to evaluate the effect of germination (0, 24, 48, and 72 h) on the physicochemical properties, content of bioactive compounds, and antioxidant capacity of three varieties of quinoa: white, red, and black high Andean from Peru. Color, nutritional composition, mineral content, phenolic compounds, flavonoids, and antioxidant activity were analyzed. Additionally, infrared spectra were obtained to elucidate structural changes during germination. The results showed color variations and significant increases (p < 0.05) in proteins, fiber, minerals, phenolic compounds, flavonoids, and antioxidant capacity after 72 h of germination, attributed to the activation of enzymatic pathways. In contrast, the infrared spectra showed a decrease in the intensity of functional groups -CH-, -CH2-, C-OH, -OH, and C-N. Correlation analysis showed that flavonoids mainly contributed to antioxidant activity (r = 0.612). Germination represents a promising alternative to develop functional ingredients from germinated quinoa flour with improved nutritional and functional attributes.

Analysis of the antioxidant activity of toons sinensis extract and their biological effects on broilers

Plant extracts are rich in a variety of nutrients and contain a large number of bioactive compounds, and compared with traditional feed additives, they have advantages such as wide sources, natural safety and rich nutrition. This study employed in vitro antioxidant and animal experiments to comprehensively evaluate the use of Toona sinensis extract (TSE) in broiler production. 508 1-day-old Cobb 500 broilers were randomly assigned to the 7 experimental groups with 6 replications and 12 birds/replicate. Two groups received Vitamin C (VC) 300 g/t and Vitamin E 500 g/t, and five dose groups of TSE received 0, 300, 600, 900, and 1,200 g/t of TSE in their feed. The study spanned 42 days, with a starter phase (1-21 days) and a finisher phase (22-42 days). The results showed that compared to ascorbic acid, TSE had the scavenging ability of 2,2-Diphenyl-1-picrylhydrazyl and hydroxyl radical, with IC50 values of 0.6658 mg/mL and 33.1298 mg/mL, respectively. Compared to TSE 0 group, broilers fed with 1,200 g/t TSE showed significant weight gain during the starter phase and increased the feed-to-weight gain ratio during both the starter and finisher phases. Additionally, broilers receiving 1,200 g/t TSE had enhanced dry matter and organic matter utilization. Concerning meat quality, broilers in the 1,200 g/t TSE group demonstrated increased cooked meat yield, and pH value, as well as higher antioxidant capacity (T-AOC), dismutase (SOD), and glutathione peroxidase (GSH-PX) in serum. In addition, there was no significant difference in ileal microflora due to TSE supplementation. In summary, this study confirms the positive impact of a dietary inclusion of 1,200 g/t TSE on broiler growth, meat quality, and serum antioxidants.

Structural characterization and stability of glycated bovine serum albumin-kaempferol nanocomplexes

Kaempferol (Kae), a flavonoid is endowed with various functions. However, due to its poor water solubility and stability, its application in the food and pharmaceutical fields remains elusive. Emerging reports have emphasized the importance of bovine serum albumin (BSA), and glycosylated BSA (GBSA) prepared in the nature deep eutectic solvent system as drug delivery system carriers. In our study, ultraviolet and fluorescence spectra revealed the higher interactions of BSA and GBSA with Kae. Through analysis of Z-average diameter, zeta-potential, polydispersity index (PDI), encapsulation efficiency (EE), loading capacity (LC) of BSA-Kae nanocomplexes (NPs) and GBSA-Kae NPs, GBSA-Kae NPs showed a higher absolute value of zeta-potential and lower PDI, while its EE and LC were also higher. Structural characterization and stability analysis revealed that GBSA-Kae NPs had more stable properties. This study laid the theoretical foundation for improving the solubility and stability of Kae during its delivery and transport.

Bioaccessibility and bioactive potential of different phytochemical classes from nutraceuticals and functional foods

Nutraceuticals and functional foods are composed of especially complex matrices, with polyphenols, carotenoids, minerals, and vitamins, among others, being the main classes of phytochemicals involved in their bioactivities. Despite their wide use, further investigations are needed to certify the proper release of these phytochemicals into the gastrointestinal medium, where the bioaccessibility assay is one of the most frequently used method. The aim of this review was to gather and describe different methods that can be used to assess the bioaccessibility of nutraceuticals and functional foods, along with the most important factors that can impact this process. The link between simulated digestion testing of phytochemicals and their in vitro bioactivity is also discussed, with a special focus on the potential of developing nutraceuticals and functional foods from simple plant materials. The bioactive potential of certain classes of phytochemicals from nutraceuticals and functional foods is susceptible to different variations during the bioaccessibility assessment, with different factors contributing to this variability, namely the chemical composition and the nature of the matrix. Regardless of the high number of studies, the current methodology fails to assume correlations between bioaccessibility and bioactivity, and the findings of this review indicate a necessity for updated and standardized protocols.

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.

Antioxidant and In Vivo Hypoglycemic Activities of Ethanol Extract from the Leaves of Engelhardia roxburghiana Wall, a Comparative Study of the Extract and Astilbin

The leaves of Engelhardia roxburghiana Wall (LERW) has been used as sweet tea in China throughout history. In this study, the ethanol extract of LERW (E-LERW) was prepared and the compositions were identified by HPLC-MS/MS. It indicates that astilbin was the predominant component in E-LERW. In addition, E-LERW was abundant in polyphenols. Compared to astilbin, E-LERW presented much more powerful antioxidant activity. The E-LERW also had stronger affinity with α-glucosidase and exerted more vigorous inhibitory effect on the enzyme. Alloxan-induced diabetic mice had significantly elevated glucose and lipid levels. Treatment with E-LERW at the medium dose (M) of 300 mg/kg could reduce the levels of glucose, TG, TC, and LDL by 16.64%, 12.87%, 32.70%, and 22.99%, respectively. In addition, E-LERW (M) decreased food intake, water intake, and excretion by 27.29%, 36.15%, and 30.93%, respectively. Moreover, E-LERW (M) therapy increased the mouse weight and insulin secretion by 25.30% and 494.52%. With respect to the astilbin control, E-LERW was more efficient in reducing the food and drink consumption and protecting pancreatic islet and body organs from alloxan-induced damage. The study demonstrates that E-LERW may be a promising functional ingredient for the adjuvant therapy of diabetes.

Evaluation of Taraxacum mongolicum flavonoids in diets for Channa argus based on growth performance, immune responses, apoptosis and antioxidant defense system under lipopolysaccharide stress

To ascertain the effects of Taraxacum mongolicum flavonoids (TMF) on the growth performance, digestive enzyme activity, immune indices, inflammatory response and antioxidant capacity of Channa argus, 400 C. argus with an average body weight of (8.08 ± 0.21) g were selected and divided randomly into four groups. They were fed with four experimental diets supplemented with TMF of 0 (control), 25, 50 and 100 mg/kg for 56 d, and then challenged with lipopolysaccharide (LPS) for 96 h, afterwards indices were detected. The results manifested that the addition of TMF above 50 mg/kg in the dietary could significantly improve the final body weight, WGR, SGR and PER of C. argus, while decreased FCR (P < 0.05). Similarly, the 50 mg/kg group had the highest activity of digestive enzymes (protease, lipase, amylase) in intestine and hepatopancreas, which were notably higher than those in the control group (P < 0.05). Nevertheless, 100 mg/kg group could effectively inhibit the liver and gut injury caused by LPS and reduce the contents of ALT and AST, LPS and LBP in serum. In the immune (LY, AKP, ACP, IgM, C3) and antioxidant (T-AOC, SOD, CAT, GSH-PX, GR, ASA, MDA) systems, 100 mg/kg groups were the optimal group, which were remarkably higher than those of the control group (P < 0.05). Additionally, the expression of genes revealed that 100 mg/kg group could noteworthy restrain the expression of pro-inflammatory factors (tnf-α, il-1β, il-8) and pro-apoptosis (cas-3,8,9, p53, bax, bcl-2) related genes, up-regulate the expression of anti-inflammatory (il-10, tgf-β) factors, antioxidant-related (nrf2, gpx, gst, cat) genes and heat shock proteins (hsp70, hsp90). Simultaneously, the survival rate of C. argus in the 100 mg/kg TMF-supplemented group was the highest after LPS challenge. Our results elucidate that dietary supplementation TMF protects C. argus from LPS-induced inflammatory injury, to ameliorate digestion, immune response, antioxidant status and apoptosis, implying that TMF could be regarded as an anti-inflammatory and antioxidant agent adding to aquatic animal feed.

Bioaccessibility of Phenolic Acids and Flavonoids from Buckwheat Biscuits Prepared from Flours Fermented by Lactic Acid Bacteria

The literature reports that the consumption of common buckwheat (Fagopyrum esculentum Moench), exactly the polyphenols it contains, is associated with a wide spectrum of health benefits. Therefore, the determination of the bioaccessibility of phenolic acids and flavonoids from buckwheat biscuits formulated from liquid-state fermented flours (BB_F) by selected lactic acid bacteria (LAB) after gastrointestinal digestion was addressed in this study. Bioaccessibility could be defined as the fraction of a compound that is released from the food matrix in the gastrointestinal lumen and used for intestinal absorption. The bioaccessibility of eight phenolic acids (protocatechuic, vanillic, syringic ferulic, caffeic, sinapic, p-coumaric, and t-cinnamic) and six flavonoids (epicatechin, vitexin, orientin, apigenin, kaempferol, and luteolin) were provided for BB_F and BB_C (buckwheat biscuits prepared from fermented and unfermented flours, respectively). The bioaccessibility indexes (BI) indicated the high bioaccessibility of phenolic acids and improved bioaccessibility of flavonoids from BB_F. Moreover, the data provide evidence for the suitability of selected LAB strains to be used as natural sour agents for further bakery product development rich in phenolic acids and flavonoids with LAB-dependent bioaccessibility.

The Role of Amaranth, Quinoa, and Millets for the Development of Healthy, Sustainable Food Products-A Concise Review

The selection of sustainable crops adaptable to the rapidly changing environment, which also cater to the dietary needs of the growing population, is a primary challenge in meeting food security. Grains from ancient crops such as amaranth, quinoa, and millets are positioned to address this challenge and hence have gained dietary predominance among cereals and pseudocereals due to their nutritional value and energy efficiency. From a nutritional perspective, they are recognized for their complete protein, phenolic compounds and flavonoids, prebiotic fibers, and essential micronutrients, including minerals and vitamins. Bioactive peptides from their proteins have shown antihypertensive, antidiabetic, antioxidant, and anticancer properties. The nutritional diversity of these grains makes them a preferred choice over traditional cereals for developing healthy, sustainable food products such as plant-based dairy, vegan meats, and gluten-free products. With growing consumer awareness about sustainability and health, the categories mentioned above are transitioning from ‘emerging’ to ‘mainstream’; however, there is still a significant need to include such healthy grains to fulfill the nutritional gap. This review article emphasizes the health benefits of amaranth, quinoa, and millet grains and discusses the recent research progress in understanding their application in new sustainable food categories. The challenges associated with their incorporation into novel foods and future research directions are also provided.

Phenolic Compounds and Antioxidant Activity of Rice–Tartary Buckwheat Composite as Affected by In Vitro Digestion

The present study aimed to evaluate the phenolic compounds and antioxidant activity of rice–tartary buckwheat composite (RTBC) as affected by in vitro digestion to explore the structure-activity relationship of the release of total phenolic content (TPC) and total flavonoid content (TFC) with the antioxidant activity of RTBC during in vitro oral, gastric, and intestinal digestion stages. The release of TPC and TFC from RTBC increased significantly after in vitro digestion ( $P<0.05$ ), and the change of antioxidant activity was consistent with that of TPC and TFC. Compared with the initial stage of digestion, the antioxidant activity of RTBC was increased after digestion ( $P<0.05$ ), and there was a strong correlation between antioxidant activity and the release of TPC and TFC (0.954 < R < 0.997; $P<0.05$ ). The phenolic compounds released in the oral, gastric, and intestinal digestion stages varied, and eight phenolic compounds were identified by UPLC-Triple-TOF/MS, namely, quercetin-3-O-robinoside-7-O-sophoroside, quercetin-3-O-neohesperidoside-7-O-glucoside, forsythobiflavone A, forsythobiflavone B, quercetin-3-O-rutinoside-7-O-glucoside, rutin, isoquercetin, and ferulic acid. These results indicated that in vitro digestion significantly increases the release of phenolic compounds and flavonoids from RTBC and there is a higher antioxidant activity after digestion than before digestion. The phenolic compounds released after digestion of RTBC are beneficial to health protection.

Bioaccessibility of phenolics from carob (Ceratonia siliqua L.) pod powder prepared by cryogenic and vibratory grinding

Carob pod powder prepared by cryogenic (CG) and vibratory grinding for 4 min (VG-4) and 8 min (VG-8) was evaluated for its antioxidant properties, and phenolic content. The bioaccessibility of phenolics was determined after the oral, gastric, and intestinal digestion phases in vitro. CG carob powder had a higher total phenolic content (6.46 mg gallic acid/g) and antioxidant capacities in terms of DPPH (15.60 mg Trolox/g) and ABTS (28.58 mg Trolox/g) assays. Quercitrin (44.54-64.68 μg/g) and cinnamic acid (27.48-31.40 μg/g) were the most abundant phenolics in all carob powder samples determined by liquid chromatography. The bioaccessibility of only ferulic acid (108%) had increased after digestion of the CG carob powder. Vibratory grinding (VG-4 and VG-8) improved the bioaccessibility of cinnamic acid (86-87%), vanillic acid (87-95%), quercitrin (33-34%), and naringenin (19-22%). A better bioaccessibility of phenolic constituents was observed for vibratory ground carob powder.

Peruvian Andean grains: Nutritional, functional properties and industrial uses

The Andean geography induces favorable conditions for the growth of food plants of high nutritional and functional value. Among these plants are the Andean grains, which are recognized worldwide for their nutritional attributes. The objective of this article is to show the nutritional and functional properties, as well as industrial potential, of Andean grains. Quinoa, amaranth, canihua, and Andean corn are grains that contain bioactive compounds with antioxidant, antimicrobial, and anti-inflammatory activities that benefit the health of the consumer. Numerous in vitro and in vivo studies demonstrate their functional potential. These high-Andean crops could be used industrially to add value to other functional food products. These reports suggest the inclusion of these grains in the daily diets of people and the application of their active compounds in the food industry.

Digestive recovery of polyphenols, antioxidant activity, and anti-inflammatory activity of selected edible flowers from the family Fabaceae

Edible flowers are regaining popularity as therapeutic agents, due to their phytochemical composition. The present study assessed the recovery of phenolics along with the antioxidant and anti-inflammatory properties of seven edible flowers of the Fabaceae family after being subjected to simulated gastrointestinal conditions and dialysis. The total phenolic content of all the flowers decreased after the gastric phase, whereas the total flavonoid content increased. The total anthocyanin content of four flower species decreased after the intestinal phase of digestion. Cassia auriculata expressed the highest hydrogen peroxide and nitric oxide scavenging activities in the dialyzed fraction. Bauhinia racemose had the highest activity in the inhibition of heat-induced hemolysis of red blood cells after dialysis (4.43 ± 01.5%). In general, the results suggest a reduction in the phenolic contents after gastrointestinal digestion and dialysis; however, phenolics, flavonoids and anthocyanins were sufficiently available to be absorbed with the dialysis to exert antioxidant and anti-inflammatory activities. PRACTICAL APPLICATION: The presence of various phenolic compounds in edible flowers has attracted the attention of consumers as well as the food industry, due to their potential to be incorporated in functional foods and drugs. However, the availability of phenolics after digestion is an important measure to get a realistic view of the health effects exerted upon the consumption of these edible flowers. The present study provides new information on the antioxidant and anti-inflammatory potential of selected edible flowers before and after in vitro digestion. This would be more useful for nutritionists, policymakers and consumers to effectively utilize edible flowers by understanding the changes undergone by the phenolic compounds upon digestion.

Transcriptomics and metabolomics analyses of the mechanism of flavonoid synthesis in seeds of differently colored quinoa strains

Quinoa (Chenopodium quinoa Willd.) is an herb of the genus Chenopodiaceae that is native to the Andes Mountains of South America. To understand the metabolic differences between various quinoa strains, we selected quinoa strains of four colors (black, red, yellow, and white) and we subjected seeds to extensive targeted metabolomics analysis using liquid chromatography-tandem mass spectrometry and transcriptomics analysis. In total, 90 flavonoid-related metabolites were detected in quinoa seeds of the four colors. We elucida ted the regulatory mechanisms of flavonoid biosynthesis in the different quinoa varieties, and thus identified key genes for flavonoid biosynthesis. The results showed that 18 flavone metabolites and 25 flavonoid-related genes were key contributors to flavonoid biosynthesis in quinoa seeds. The results of this study may provide a basis for the breeding and identification of new quinoa strains and for the screening of potential target genes in flavonoid biosynthesis regulation in quinoa.

Statistical Approach to Potentially Enhance the Postbiotication of Gluten-Free Sourdough

Fermented products are permanently under the attention of scientists and consumers, both due to nutritional importance and health promoting effects. The fermented functional foods contribute to a more balanced diet and increase the immune responses (among many other health effects) with positive implications for quality of life. In this sense, improving the sourdough’s fermentation to boost the biotic (postbiotic and paraprobiotic) properties of the sourdough-based products has positive impacts on the nutritional and functional properties of the final baked products. These enhanced sourdoughs can be obtained in controlled fermentation conditions and used as sourdough bread improvers or novel bioingredients. In this context, our work aimed to optimize, using statistical tools, a gluten-free sourdough based on chickpea, quinoa, and buckwheat fermentation with selected lactic acid bacteria (LAB) to enhance its postbiotic properties. The most important biotechnological parameters were selected by Plackett–Burman Design (PBD) and then Response Surface Methodology (RSM) was applied to evaluate the interactions between the selected factors to maximize the gluten-free sourdough’s properties. As a result, the optimized fermented sourdough had antimicrobial activity with inhibition ratios between 71 and 100% against the Aspergillus niger, Aspergillus flavus, Penicillium spp. molds and against the Bacillus spp endospore-forming Gram-positive rods. The optimized variant showed a total titratable acidity (TTA) of 40.2 mL NaOH 0.1N. Finally, the high-performance liquid chromatography (HPLC) analysis highlighted a heterofermentative profile for the organic acids from the optimized sourdough. Among flavonoids and polyphenols, the level of caffeic and vanillic acids increased after lactic acid fermentation. The comparison between the optimized sourdough and the control evidenced significant differences in the metabolite profiles, thus highlighting its potential postbiotication effect.

Functional Components and Anti-Nutritional Factors in Gluten-Free Grains: A Focus on Quinoa Seeds

Quinoa (Chenopodium quinoa Willd.) has recently received increasing interest from both scientists and consumers due to its suitability in gluten-free diets, its sustainability, and its claimed superfood qualities. The aim of this paper is to systematically review up-to-date studies on quinoa functional components and anti-nutritional factors, in order to define a baseline for food scientists approaching the investigation of quinoa phytochemicals and providing evidence for the identification of healthier sustainable foods. State of the art evaluations of phytochemical contents in quinoa seeds were obtained. It emerged that phenolic compounds are the most investigated functional components, and spectrophotometric methods have been mostly applied, despite the fact that they do not provide information about single components. Saponins are the most studied among anti-nutritional factors. Betalains, tannins, and phytoecdysteroids have been poorly explored. Information on factors affecting the phytochemical content at harvesting, such as quinoa ecotypes, crop geographical location and growing conditions, are not always available. A comprehensive characterization, encompassing several classes of functional components and anti-nutritional factors, is mainly available for quinoa varieties from South America. However, defining a standard of quality for quinoa seeds is still challenging and requires a harmonization of the analytical approaches, among others.