Using combined optimization, GC-MS and analytical technique to analyze the germination effect on phenolics, dietary fibers, minerals and GABA contents of Kodo millet (Paspalum scrobiculatum)

Change of physiochemical characteristics, nutritional quality, and volatile compounds of Chenopodium quinoa Willd. during germination

The impacts of varying germination periods (0-72 h) on morphological properties, proximate composition, amino acid profile, GABA levels, antioxidant attributes, polyphenol content (both free and bound), and volatile compounds of quinoa were evaluated. Germination significantly increased the content of fiber, amino acids, GABA, polyphenols, and in-vitro antioxidant activities in quinoa. The optimal nutritional quality and antioxidant capacity of quinoa were observed during the 36-72 h germination period. We examined the dynamics of 47 phenolic compounds in quinoa during germination and noted a substantial rise in free phenolic acids and bound flavonoids post-germination. A total of 53 and 84 volatile compounds were respectively identified in ungerminated quinoa and germinated quinoa. It was found that the germination period of 24-48 h contributed to reducing the presence of undesirable flavors. TEM analysis revealed significant structural damage to the ultrastructure and relaxation of the cell wall in germinated quinoa grains.

Optimizing the effect of ultrasonication and germination on antinutrients and antioxidants of kodo (Paspalum scrobiculatum) and little (Panicum sumatrense) millets

Kodo (Paspalum scrobiculatum) and little (Panicum sumatrense) millet grains were utilized to minimize their antinutrient content (phytate and tannin) and maximize their antioxidant activity (DPPH) by studying the effect of ultrasonication time, germination time and temperature using central composite rotatable design. Results revealed the optimum conditions for producing ultrasonicated and germinated kodo and little millet flour of the highest antioxidant activity and lowest antinutrient content (phytate and tannin) by using 30 min for ultrasonication, 72 h for germination at 40 °C. Further, a second order model was developed to describe and predict the effect of process variables on antioxidant activity and antinutrient contents. Extended experiments were carried out under the optimized conditions to validate the developed model. The antioxidant activity obtained was 88.46% RSA and 89.06% RSA for kodo and little millet grain flours, respectively whereas antinutrient content for phytate was 0.165 mol/kg and 0.199 mol/kg and for tannin 2.88 mol/kg and 9.51 mol/kg, for kodo and little millet grain flours, respectively. This study provides useful information about the potential utilization of ultrasonicated and germinated kodo and little millet grain flours for the development of functional foods.

Gamma-aminobutyric acid (GABA): a comprehensive review of dietary sources, enrichment technologies, processing effects, health benefits, and its applications

Gamma-aminobutyric acid (GABA) is a naturally occurring potential bioactive compound present in plants, microorganisms, animals, and humans. Especially, as a main inhibitory neurotransmitter in the central nervous system, GABA possesses a broad spectrum of promising bioactivities. Thus, functional foods enriched with GABA have been widely sought after by consumers. However, the GABA levels in natural foods are usually low, which cannot meet people's demand for health effects. With the increasing public awareness on the food securities and naturally occurring processes, using enrichment technologies to elevate the GABA contents in foods instead of exogenous addition can enhance the acceptability of health-conscious consumers. Herein, this review provides a comprehensive insight on the dietary sources, enrichment technologies, processing effects of GABA, and its applications in food industry. Furthermore, the various health benefits of GABA-enriched foods, mainly including neuroprotection, anti-insomnia, anti-depression, anti-hypertensive, anti-diabetes, and anti-inflammatory are also summarized. The main challenges for future research on GABA are related to exploring high GABA producing strains, enhancing the stability of GABA during storage, and developing emerging enrichment technologies without affecting food quality and other active ingredients. A better understanding of GABA may introduce new windows for its application in developing functional foods.

Multipin cold plasma electric discharge on hydration properties of kodo millet flour: Modelling and optimization using response surface methodology and artificial neural network – Genetic algorithm

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Hydration properties of kodo millet flour was improved with plasma treatment.

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Independent variables such as voltage and time were optimized with RSM and ANN – GA.

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ANN – GA showed best optimized combination as compared to RSM.

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DSC, FTIR, XRD and SEM had positive effect on millet flour for optimized values.

The effect on functional properties of kodo millet flour was studied using multipin cold plasma electric reactor. The analysis was carried out at various levels of voltage (10–20 kV) and treatment time (10–30 min) for four different parameters such as water absorption capacity (WAC), oil absorption capacity (OAC), solubility index (SI) and swelling capacity (SC). Response surface methodology (RSM) and artificial neural network – genetic algorithm (ANN – GA) were adopted for modelling and optimization of process variables. The optimized values obtained from RSM were 20 kV and 17.9 min. On the contrary, 17.5 kV and 23.3 min were the optimized values obtained from ANN – GA. The RSM optimal values of WAC, OAC, SI and SC were 1.51 g/g, 1.40 g/g, 0.06 g/g and 3.68 g/g whereas optimized ANN – GA values were 1.51 g/g, 1.50 g/g, 0.06 g/g and 4.39 g/g, respectively. Infrared spectra, peak temperature, diffractograms and micrographs of both optimized values were analyzed and showed significant differences. ANN showed a higher value of R² and lesser values of other statistical parameters compared to RSM. Therefore, ANN – GA was treated as the best model for optimization and modelling of cold plasma treated kodo millet flour. Hence, the ANN – GA optimized values of cold plasma treated flour could be utilized for practical applications in food processing industries.

The yield, nutritional value, umami components and mineral contents of the first-flush and second-flush Pleurotus pulmonarius mushrooms grown on three forestry wastes

This study was carried out to evaluate the yields and quality of the first-flush and second-flush Pleurotus pulmonarius mushrooms grown on three forestry wastes (pine, poplar, and honeysuckle rattan). The biological efficiency (BE) of the substrates varied from 61.89% to 81.01%. The total protein content, gamma-aminobutyric acid (GABA) content and equivalent umami concentration (EUC) values of the mushrooms were greatly influenced by the flush number and the substrate, however, the total sugar content and ergosterol content of the mushrooms were not significantly affected. The first-flush mushrooms that were grown on the pine sawdust-based substrate had the highest protein content, and the first-flush mushrooms that were grown on the honeysuckle rattan sawdust-based substrate had the highest GABA content and EUC values. All the mushroom samples accumulated Cu but excluded Ca, Mn, Pb, Cr, and Cd, and the concentrations of Mg, Fe, and Mn are species and flush number dependent.

Understanding the Antinutritional Factors and Bioactive Compounds of Kodo Millet (Paspalum scrobiculatum) and Little Millet (Panicum sumatrense)

Kodo and little millet (Kutki) have a variety of phytochemical constituents including derivatives of hydroxybenzoic acid and hydroxycinnamic acids, myricetin, catechin, luteolin, apigenin, daidzein, naringenin, kaempferol, and quercetin with vast health benefits and thus can be utilized as functional food ingredients. Millet-based foods and their food products have physiological and health-promoting impacts, notably antidiabetic, anti-obesity, and cardiovascular disease, and based on the actions of phytochemicals, it plays a major role in the body’s immune system. However, antinutrients (tannins, oxalate, trypsin inhibitor, and phytates) present in these millets restrict their utilization since these factors bind the essential nutrients and make them unavailable. Therefore, this review suggested overcoming the effects of antinutrients in these millets, thereby opening up important applications in food industries that may promote the development of novel functional foods. Various methods were discussed to eliminate the antinutrient factors in these millets, and hence, the review holds immense significance to the food industry for effectively utilizing these millets to develop value-added RTE/RTC products/functional food/beverages.

Effect of Different Processing Methods on the Millet Polyphenols and Their Anti-diabetic Potential

Interest in polyphenols has grown due to their beneficial effect on diabetes attenuation. Millets are ancient crops that are rich in polyphenols and used for both food and feed. They are grown worldwide and are adapted to production under dry, hot conditions. The polyphenols found in millets have anti-diabetic properties. However, millet is usually consumed after being processed by heating, germination, fermentation, and other processing methods, which may alter polyphenol content and thus affect their anti-diabetic potential. This mini-review profiles the effects of different processing methods on millet polyphenols and how changes in millet polyphenols affect the hypoglycemic effect of millet. Future studies are needed to compare the anti-diabetes potential of millet polyphenols before and after processing and to explore ways to minimize polyphenol losses and thus maintain their hypoglycemic effect in final products.

Modern Processing of Indian Millets: A Perspective on Changes in Nutritional Properties

Globally, billions of people are experiencing food insecurity and malnutrition. The United Nations has set a global target to end hunger by 2030, but we are far from reaching it. Over the decade, climate change, population growth and economic slowdown have impacted food security. Many countries are facing the challenge of both undernutrition and over nutrition. Thus, there is a need to transform the food system to achieve food and nutrition security. One of the ways to reach closer to our goal is to provide an affordable healthy and nutritious diet to all. Millets, the nutri-cereals, have the potential to play a crucial role in the fight against food insecurity and malnutrition. Nutri-cereals are an abundant source of essential macro- and micronutrients, carbohydrates, protein, dietary fiber, lipids, and phytochemicals. The nutrient content and digestibility of millets are significantly influenced by the processing techniques. This review article highlights the nutritional characteristics and processing of Indian millets, viz. foxtail, kodo, proso, little, and pearl millets. It also envisages the effect of traditional and modern processing techniques on millet’s nutritional properties. An extensive literature review was conducted using the research and review articles related to processing techniques of millets such as fermentation, germination, dehulling, extrusion, cooking, puffing, popping, malting, milling, etc. Germination and fermentation showed a positive improvement in the overall nutritional characteristics of millets, whereas excessive dehulling, polishing, and milling resulted in reduction of the dietary fiber and micronutrients. Understanding the changes happening in the nutrient value of millets due to processing can help the food industry, researchers, and consumers select a suitable processing technique to optimize the nutrient value, increase the bioavailability of nutrients, and help combat food and nutrition security.

Determination of Essential Minerals and Trace Elements in Edible Sprouts from Different Botanical Families—Application of Chemometric Analysis

Background: elemental deficiency may result in the malfunctioning of human organisms. Sprouts, with their attractive looks and well-established popularity, may be considered as alternative sources of elements in the diet. Moreover, the uptake of micro- and macronutrients from sprouts is better when compared to other vegetable sources. The aim of the study was to determine and compare the level of the selected essential minerals and trace elements in 25 sprouts from different botanical families, to preselect the richest species of high importance for human diets. Methods: the Cu, Zn, Mn, Fe, Mg, Ca determinations were performed using atomic absorption spectrometry with flame atomization and iodine by the colorimetric method. Results: beetroot sprouts had the highest levels of Zn, Fe, and Mg, while onion sprouts were the richest in Mn and Ca, among all of the tested sprouts. Sprouts of the Brassicaceae family were generally richer in Ca, Mg, and Zn than sprouts from the Fabaceae family. Results allow preselection of the most perspective sprouts as possible dietary sources of essential minerals and trace elements. For rucola, leeks, onions, and beetroot sprouts, the data on minerals and trace element compositions were performed for the first time.

Dough Rheological Properties, Microstructure and Bread Quality of Wheat-Germinated Bean Composite Flour

Germinated bean flour (GBF) was obtained and incorporated in different levels (5%, 10%, 15%, 20% and 25%) into dough and bread made from refined wheat flour. The incorporation of GBF into wheat flour led to a decrease of the water absorption value, dough consistency, baking strength, extensibility and improved tolerance for mixing, total gas production and α-amylase activity. Tan δ increased in a frequency-dependent manner for the samples with a GBF addition, whereas the G’ and G” decreased with the increased value of the temperature. According to the microscopic structures of the dough samples, a decrease of the starch area may be clearly seen for the samples with high levels of GBF addition in wheat flour. The bread evaluation showed that the specific volume, porosity and elasticity increased, whereas the firmness, gumminess and chewiness decreased up to a level of 15% GBF addition in wheat flour. The color parameters L*, a* and b* of the bread samples indicated a darkening effect of GBF on the crumb and crust. From the sensory point of view, the bread up to a 15% GBF addition was well-appreciated by the panelists. According to the data obtained, GBF could be recommended for use as an improver, especially up to a level of 15% addition in the bread-making industry.

Analyzing the effect of germination on the pasting, rheological, morphological and in- vitro antioxidant characteristics of kodo millet flour and extracts

The present investigationwas carried out to determine the effect of germination on pasting, rheological, morphological properties of Kodo millet flour and in-vitroantioxidant characteristics of its phenolic and γ-amino butyric acid extracts. Rheological analysis depicted complex flour viscosity decreased with an improvement in shear intensity, symbolizing the shear-thinning action of flour upon germination. The frequency and temperature sweep demonstrated a decrease in visco-elasticity as a result of germination wherein, SEM revealed destruction in the continuous composite structure of starch which got entangled in dense protein matrix following germination. The in-vitroantioxidant activities such as total antioxidant capacity, DPPH*, FRAP, metal chelating ability and hydrogen peroxide scavenging activities of both the extracts increased significantly. There was a decrease in pasting properties and gelatinization behaviour whereas, visco-elastic solid behaviour changed to visco-elastic fluid. This research explores the potential of germinated Kodo millet flour for valuable bioactive compounds extraction and its utilization in product development.

Advanced Analytical Approaches for the Analysis of Polyphenols in Plants Matrices—A Review

Phenolic compounds are plants’ bioactive metabolites that have been studied for their ability to confer extensive benefits to human health. As currently there is an increased interest in natural compounds identification and characterization, new analytical methods based on advanced technologies have been developed. This paper summarizes current advances in the state of the art for polyphenols identification and quantification. Analytical techniques ranging from high-pressure liquid chromatography to hyphenated spectrometric methods are discussed. The topic of high-resolution mass spectrometry, from targeted quantification to untargeted comprehensive chemical profiling, is particularly addressed. Structure elucidation is one of the important steps for natural products research. Mass spectral data handling approaches, including acquisition mode selection, accurate mass measurements, elemental composition, mass spectral library search algorithms and structure confirmation through mass fragmentation pathways, are discussed.

Millet: A review of its nutritional and functional changes during processing

Millets are a major source of human food, and their production has been steadily increasing in the last decades to meet the dietary requirements of the increasing world population. Millets are an excellent source of all essential nutrients like protein, carbohydrates, fat, minerals, vitamins, and bioactive compounds. However, the nutrients, bioactive compounds, and functions of cereal grains can be influenced by the food preparation techniques such as decortication/dehulling, soaking, germination/malting, milling, fermentation, etc. This study discusses the nutritional and functional changes in millet during different traditional/modern processing techniques, based on more than 100 articles between 2013 and 2020 from Web of Science, Google Scholar, FAO, and USDA databases. Our results concluded that processing techniques could be useful to combat undernourishment and other health issues. Moreover, this review provides detailed information about millet processing, which is advantageous for industry, consumers, and researchers in this area.

Free and insoluble-bound phenolics: How does the variation of these compounds affect the antioxidant properties of mustard grains during germination?

This work aimed to investigate how the variation of free and insoluble-bound phenolics affected the antioxidant properties of mustard grains from two varieties (black - Brassica nigra and white - Sinapsis alba) during different germination parameters. The germination conditions selected for each mustard variety to improve their antioxidant properties were different, as follows: (a) for white mustard - 72 h of germination at 25 °C in the dark and (b) for black mustard - 48 h of germination at 25 °C alternating dark and light periods. At these conditions, increases of 49, 72, 80, 68, 42, 66 and 45% were detected for total phenolic compounds (TPC), total flavonoids, condensed tannins, FRAP, DPPH, ABTS, and ORAC, respectively, for soluble extracts of white mustard compared to the non-germinated white mustard. The soluble extracts from black mustard, in turn, presented increases of 44, 18, 55, 29, 3, 160 and 42% for TPC, total flavonoids, condensed tannins, FRAP, DPPH, ABTS, and ORAC, respectively, compared to the non-germinated sample. Gallic acid, 3,4-di-hydroxybenzoic acid, sinapic acid, ferulic acid, coumaric acid, and rutin were identified by UPLC-MS/MS and were the main compounds detected in mustard extracts. Given the results obtained, germinated mustard grains have the potential for application as a functional and nutraceutical food.

Antioxidant properties, phenolic and mineral composition of germinated chia, golden flax, evening primrose, phacelia and fenugreek

Seeds and sprouts are of considerable interest due to their numerous pro-health benefits. The aim of this study was to investigate the effect of germination on the mineral composition (performed by flame absorption atomic spectroscopy), total phenolic content, antioxidant activity, as well as phenolic profiles (before and after alkaline hydrolysis by high-performance liquid chromatography) of chia, golden flax, evening primrose, phacelia and fenugreek seeds. Generally, significant (p < 0.05) changes in the individual minerals composition of the seeds, improvement of their antioxidant properties, as well as increase in levels of individual phenolic compounds was found after seeds germination. Alkaline hydrolysis allowed to release free forms of phenolics and to confirm (chromatographically) their significantly higher amounts when compared to the nonhydrolyzed fraction. Gallic, protocatechuic, caffeic, p-coumaric, ferulic and sinapic acids, as well as quercetin and kaempferol were identified in analyzed seeds and sprouts. Sprouts exhibited better nutritional values than their un-germinated forms.

Changes in the GABA and polyphenols contents of foxtail millet on germination and their relationship with in vitro antioxidant activity

Germination along with ultrasonic assisted extraction induced a significant beneficial effect on the characteristics of polyphenolic components profile, GABA contents and in vitro antioxidant capacity of the foxtail millet flour extracts. The total antioxidant activity (29.0-45.23 mgAAE/g) and reducing power (0.53-0.76 µg/ml) increase during germination were due to quantitative increase in phthalicacid; hex-3yl-ester; hexadecanoicacid methylester etc. whereas, increase in DPPH (48.32-59.62%) and hydrogen peroxide scavenging activities (35.44-63.07 mM-Trolox/g) were attributed to increase in hexadecanoic acid methylester; 9,12-Octadecadienoicacid ethylester and synthesis of new compounds like pentadecanoicacid; 14-methyl-methylester etc. The metal chelating abilities (34.92-57.38 mgEDTA/g) and in vitro antioxidant activity increase due to overall increase in phenolics, flavonoids along with GABA contents. Synthesis of additional polyphenolic components viz. astaxanthin, propanoicacid, 1-monolinoleoylglycerol trimethylsilylether, 9,12,15-octadecatrienoicacid etc. as a result of germinated explored the possible potential utilization of germinated foxtail millet grains in various functional and convenience food formulations.