Glutamate. Its applications in food and contribution to health

Taste properties and mechanism of umami peptides from fermented goose bones based on molecular docking and molecular dynamics simulation using umami receptor T1R1/T1R3

Umami peptides are valuable taste substances due to their exceptional taste and beneficial properties. In this study, purification of fermented goose bone broth was performed using continuous chromatography and sensory analysis, and after identification through nano-LC-MS/MS, four umami peptides were screened out by umami activity prediction and molecular docking, which are VGYDAE, GATGRDGAR, GETGEAGER, and GETGEAGERG derived from collagen. Sensory analysis indicated that they were also umami-enhancing, with thresholds ranging from 0.41 to 1.15 mmol/L, among which GER9 was the best. Combining the results of docking and molecular dynamics simulation, it was known that hydrogen bond and electrostatic interactions were vital in driving the umami formation. Moreover, Glu, Ser, and Asp of umami receptor T1R1/T1R3 were the key residues for the binding between four umami peptides and T1R1/T1R3. These findings provide novel insights into the high-value utilization of goose bones and offer profound theoretical guidance for understanding the umami mechanism.

Novel competitive electrochemical impedance biosensor for the ultrasensitive detection of umami substances based on Pd/Cu-TCPP(Fe)

The development of biosensors capable of assessing umami intensity has elicited significant attention. However, the detection range of these biosensors is constrained by the sensing components and strategies used. In this study, we introduce a novel competitive, ultra-high-sensitivity impedance biosensor by utilizing composite nanomaterials and T1R1 as a composite signal probe. Pd/Cu-TCPP(Fe) had a substantial surface area, effectively enhancing the loading capacity of the T1R1 and thus augmenting the biosensor's recognition precision. Furthermore, the Pd/Cu-TCPP(Fe) elevated peroxidase-like activity catalyzed the formation of insoluble precipitates of 4-chloro-1-naphthol (4-CN), resulting in cascaded amplification of the impedance signal. The remarkable catalytic activity of the composite signal probe endowed the biosensor with exceptional analytical performance, featuring a limit of detection (LOD) of 0.86 pg/mL and a linear detection range spanning from 10 to 10,000 pg/mL. Successful application of the biosensor for umami detection in fish was demonstrated, signifying its substantial potential in food-flavor evaluation.

Effects of vincristine and monosodium glutamate on gastrointestinal motility and visceral sensitivity

BACKGROUND

Chemotherapy-induced adverse effects are an unresolved nightmare. In preclinical studies in rats, the food additive monosodium glutamate (MSG) improved some of the side effects caused by cisplatin, but its effects in other models of chemotherapy-treated animals are not well known. The aim of this study was to test if MSG may improve some of the adverse effects induced by vincristine in rats.

METHODS

Young male Wistar rats were exposed or not to MSG (4 g L-1 ) in drinking water from week 0 till 1 week after treatment (week 3). Rats received two cycles of five daily intraperitoneal (ip) injections (Monday to Friday, weeks 1 and 2) of either saline (2 mL kg-1 ) or vincristine (0.1 mg kg-1 ). Gastrointestinal motility was measured in vivo by radiological methods after the first and tenth ip administrations. On week 3, the threshold for mechanical somatic and colorectal sensitivity was recorded using Von Frey filaments applied to the paws and an intracolonic balloon, respectively. Finally, samples of the terminal ileum and distal colon were histologically evaluated in sections.

KEY RESULTS

Vincristine reduced body weight gain, food intake, and upper gastrointestinal transit, caused somatic (but not visceral) hypersensitivity and increased the thickness of the submucosal and muscle layers of the small intestine. In vincristine-treated animals, MSG partially prevented gastrointestinal dysmotility and reduced visceral sensitivity but did not improve structural alterations of the small intestine.

CONCLUSIONS & INFERENCES

MSG could be used as an adjuvant to conventional treatments to improve some gastrointestinal dysfunctions caused by chemotherapy.

Ribonucleotides differentially modulate oral glutamate detection thresholds

The savory or umami taste of the amino acid glutamate is synergistically enhanced by the addition of the purines inosine 5'-monophosphate (IMP) and guanosine 5'-monophosphate (GMP) disodium salt. We hypothesized that the addition of purinergic ribonucleotides, along with the pyrimidine ribonucleotides, would decrease the absolute detection threshold of (increase sensitivity to) l-glutamic acid potassium salt (MPG). To test this, we measured both the absolute detection threshold of MPG alone and with a background level (3 mM) of 5 different 5'-ribonucleotides. The addition of the 3 purines IMP, GMP, and adenosine 5'-monophosphate (AMP) lowered the MPG threshold in all participants (P < 0.001), indicating they are positive modulators or enhancers of glutamate taste. The average detection threshold of MPG was 2.08 mM, and with the addition of IMP, the threshold was decreased by approximately 1.5 orders of magnitude to 0.046 mM. In contrast to the purines, the pyrimidines uridine 5'-monophosphate (UMP) and cytidine 5'-monophosphate (CMP) yielded different results. CMP reliably raised glutamate thresholds in 10 of 17 subjects, suggesting it is a negative modulator or diminisher of glutamate taste for them. The rank order of effects on increasing sensitivity to glutamate was IMP > GMP> AMP >> UMP// CMP. These data confirm that ribonucleotides are modulators of glutamate taste, with purines enhancing sensitivity and pyrimidines displaying variable and even negative modulatory effects. Our ability to detect the co-occurrence of glutamate and purines is meaningful as both are relatively high in evolutionarily important sources of nutrition, such as insects and fermented foods.

A Study on the Awareness and Perceptions Regarding Monosodium Glutamate and its Potential Health Effects Amongst the Urban Population of Saudi Arabia

Introduction Monosodium glutamate (MSG), a common global food additive in processed foods, influences flavors and textures due to its chemical complexity and nutritional intricacy. Despite an annual production of 1.9 million tons and historical safety concerns, the multifaceted impact on health, ranging from metabolic disorders to neurological and cardiovascular implications, necessitates ongoing research for informed consumption and balanced dietary practices. Materials and methods This cross-sectional study investigates MSG-associated intricacies among Saudi Arabia's urban population. The research included questionnaire development, translation, and cultural adaptation, and was validated by nutrition experts. A sample size of 420 was calculated for a 95% confidence level. Data collection occurred from September 13 to October 31, 2023, and ethical considerations were ensured. Statistical analysis, including chi-square tests, regression analysis, and SPSS, explored intricacy relationships. Results The MSG intricacy study in Saudi Arabia's urban population, involving 420 respondents, showed statistically significant correlations (P < 0.05) in demographics. The key findings indicate an awareness of the impact of MSG on health, its associations with various conditions, and strong support for its exclusion from foods. Region, gender, age, and social status correlations highlighted diverse perspectives. The Western province showed the highest response rate at 42.61%, prompting regional awareness questions. Gender dynamics showed that 90.47% of the respondents were females, emphasizing potential gender-specific concerns. Concentration among ages 20-30 (61.9%) underscored generational factors. While commendable baseline awareness was noted, 73.09% of the participants believing MSG is harmful prompts further investigation. Emotional responses, including happiness (25.95%) and frustration (18.33%), highlight the complexity of the individuals' experiences, emphasizing the need for tailored communication strategies. Conclusion The MSG intricacy study in Saudi Arabia's urban population reveals insights into knowledge, attitudes, and behaviors, emphasizing the need for nuanced interventions considering regional and emotional differences. The findings underscore health concerns, supporting regulations, and knowledge impact on behavior. This survey serves as a valuable tool for informed public discourse and decision-making in the unique socio-cultural context of urban Saudi Arabia.

The interplay between monosodium glutamate (MSG) consumption and metabolic disorders

Monosodium glutamate (MSG) is one of the most popular food additives in the world and is often ingested with commercially processed foods. It can be described as a sodium salt of glutamic acid with the IUPAC name - Sodium 2-aminopentanedioate and is ionized by water to produce free sodium ions and glutamic acid. MSG use has significantly increased over the past 30 years, its global demand stands huge at over three million metric tons which is worth over $4.5 billion. Asia was responsible for more than three quarter of world MSG consumption with the country China also leading in global consumption as well as production and export to other countries. Prior to year 2020, global demand for MSG increased by almost four percent each year with the highest significant increase in demand for MSG predicted to rise in Thailand, Indonesia, Vietnam and China, followed by Brazil and Nigeria. However, several researches featured in this review has identified MSG consumption as a major contributor to the development and progression of some metabolic disorders such as obesity, which is a risk factor for other metabolic syndromes like hypertension, diabetes mellitus and cancer initiation. The mechanism by which MSG induce obesity involves induction of hypothalamic lesion, hyperlipidemia, oxidative stress, leptin resistance and increased expression of peroxisome proliferator-activated receptors (PPARs) Gamma and Alpha. Similarly for induction of diabetes mellitus, MSG consumption resulted in decreased pancreatic beta cell mass, increased oxidative stress and metabolic rates, reduced glucose and insulin transport to adipose tissue and skeletal muscles, insulin insensitivity, reduced insulin receptors and induced severe hyperinsulinemia. Dietary salt, an active component of MSG is also found to be a major risk factor for high blood pressure (which may lead to hypertension). MSG is used to enhance the taste of tobacco, causing smokers to consume the product in excess and thereby increasing the risk of cancer development. Depending on the amount consumed, MSG has both positive and negative effects. Despite the controversy surrounding MSG's safety and its probable contribution to risk of development and progression of metabolic disorders, its global consumption is still very high. Therefore, this article will sensitize the public on the need for cautious use of MSG in foods and also aid regulatory agencies to further review the daily MSG consumption limit based on metabolic toxicities observed at the varied dosages reported in this review.

Enhancing saltiness perception by chemosensory interaction: an fMRI study

Neuroimaging studies that focus on taste, odor, and their interactions can specify their capability to elicit brain regions responsible for flavor perception and reward. Such information would be useful for formulating healthy food products, such as low salt food. In this study, a sensory experiment was conducted to investigate the capability of cheddar cheese odor, monosodium glutamate (MSG), and their interactions to enhance saltiness perception and preference of NaCl solutions. The activated brain areas in response to odor-taste-taste interactions were then investigated using an fMRI study. The results of the sensory tests showed that saltiness and preference of NaCl solutions were enhanced in the presence of MSG + cheddar cheese odor. According to the fMRI study, the stimulus with a higher salty rate activated the rolandic operculum, and the stimulus with a higher preference activated the rectus, medial orbitofrontal cortex, and substantia nigra. Moreover, the activation of multiple regions, such as the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), temporal pole, and amygdala was observed in response to (cheddar cheese odor + MSG + NaCl) minus (odorless air + NaCl).

Sodium Replacement with KCl and MSG: Attitudes, Perception and Acceptance in Reduced Salt Soups

Sodium intake is linked to multiple negative health outcomes, particularly hypertension, the leading cause of premature death globally. Sodium intake levels in human populations are high, due in part to our desire for palatable salty-tasting foods. Two leading salt replacement strategies are the use of potassium chloride (KCl) and monosodium glutamate (MSG), the latter of which still contains some sodium, but both of which can replace some salty taste in foods while reducing net sodium levels. In this report, we employed a trained descriptive sensory panel to optimize saltiness in sodium-reduced aqueous samples using various concentrations of KCl and MSG. Following this, we assessed consumer attitudes to sodium-reduction strategies in a model food, canned soup, known to typically be high in sodium. Finally, in a large consumer test, we verified that these optimized levels of KCl and MSG did not lead to a drop in liking for the reduced-sodium soups with saltiness subsidized in this manner. Our results showed that sodium can be readily reduced in soups by 18% while actually scoring higher in liking, and in some cases being perceived as even more salty tasting, but that consumers are more open to sodium reduction in this manner when sodium replacements are not specifically highlighted, and when percentage sodium reduction is stated over absolute levels.

Characterizing the effect of sodium reduction and monosodium glutamate supplementation on white and multigrain breads

Sodium overconsumption has become a serious health concern resulting in the Food and Drug Administration (FDA) publishing voluntary sodium reduction guidelines for a wide spectrum of packaged and processed foods. Reducing sodium through the removal of salt may decrease the palatability of foods, thus increasing the need for new approaches to prevent such palatability loss. The objective of this research was to characterize white and multigrain breads with either 43% or 60% reduction in sodium and with and without monosodium glutamate (MSG) using descriptive analysis methodology as well as to identify the drivers of liking for white and multigrain breads of varying sodium contents with and without MSG. Significant differences were identified in the attributes of salty taste and aftertaste, savory aftertaste, and chewy and firm textures in white bread and of salty taste and aftertaste, sweet taste, and density in multigrain bread. By regressing consumer test data of these breads onto their principal component analysis biplots, textural attributes and salty taste and aftertaste were identified as primary drivers of liking in white and multigrain breads. Flavor enhancers such as MSG show promise in mitigating palatability loss that occurs when the sodium content of bread is greatly reduced and thus provide a promising solution to produce breads with an improved nutritional profile. Future research on flavor enhancement in other food matrices would be valuable as well as in other bread and carbohydrate-based food categories. PRACTICAL APPLICATION: The findings of our study suggest that texture and a salty taste and aftertaste drive consumer liking of reduced-sodium white and multigrain breads and liking of breads could be improved with the addition of monosodium glutamate. Increasing the acceptance of reduced-sodium food products could help to improve the health of the American population by resulting in a reduced risk of hypertension and subsequently heart attacks and stroke.

Yeast Extract: Characteristics, Production, Applications and Future Perspectives

Yeast extract is a product prepared mainly from waste brewer's yeast, which is rich in nucleotides, proteins, amino acids, sugars and a variety of trace elements, and has the advantages of low production cost and abundant supply of raw material. Consequently, yeast extracts are widely used in various fields as animal feed additives, food flavoring agents and additives, cosmetic supplements, and microbial fermentation media; however, their full potential has not yet been realized. To improve understanding of current research knowledge, this review summarizes the ingredients, production technology, and applications of yeast extracts, and discusses the relationship between their properties and applications. Developmental trends and future prospects of yeast extract are also previewed, with the aim of providing a theoretical basis for the development and expansion of future applications.

Consumer acceptance of reduced sodium white and multigrain bread: Impact of flavor enhancement and ingredient information on sample liking

Chronic consumption of sodium in quantities exceeding recommendations has led to sodium being designated as a nutrient of health concern for overconsumption. As a result of the prevalence of sodium overconsumption, the Food and Drug Administration (FDA) released voluntary sodium reduction goals for a wide variety of products on both short- and long-term timespans. As food palatability may decrease when sodium is reduced, flavor enhancers such as monosodium glutamate (MSG) may provide a promising solution to mitigate such palatability loss. The objective of this research was to investigate consumer acceptance of white and multigrain breads with either a 43% or 60% reduction in sodium content and with and without MSG as well as to investigate the influence of information on consumer acceptance of these breads under blind, informed, and informed with education conditions. Seventy-eight frequent bread consumers participated in the evaluations. A significant difference was evidenced across breads with different levels of sodium content and MSG status, although no difference was seen across the different evaluation conditions. Consumer segmentation found multiple consumer clusters showing different liking patterns of the bread treatments for both white and multigrain breads. Breads with sodium content set at the FDA's long-term goal with and without MSG were liked no differently in nearly all attributes evaluated than the full-sodium bread demonstrating the feasibility of producing acceptable reduced-sodium breads. Future research characterizing the predominant sensory attributes of full-sodium and reduced-sodium breads with and without MSG would be valuable for identifying the drivers of liking in such products. Practical Application: The findings of our study suggest that consumer liking of reduced sodium white and multigrain breads could be improved with the addition of monosodium glutamate. Increasing the acceptance of reduced sodium food products could help to reduce the risk of hypertension and subsequently heart attacks and stroke for the American population.

Reducing salt intake with umami: A secondary analysis of data in the UK National Diet and Nutrition Survey

Reducing sodium content in foods is an important public health measure to reduce salt intake and decrease the incidence of noncommunicable diseases, such as cardiovascular disease and chronic kidney disease. This study quantified the amount of salt intake that could potentially be reduced by using umami substances, including glutamate, inosinate, and guanylate, without compromising taste, for adults in the United Kingdom (UK). We used data comprised of 1834 adults aged 20 years and over from the National Diet and Nutrition Survey (NDNS RP) 2016/2017-2018/2019. Four hypothetical scenarios in which the market share of low-sodium foods accounts for 0%, 30%, 60%, or 90% of consumed products were considered in the analyses. Per capita daily salt intake corresponding to the NDNS RP food groups was calculated for each scenario, and the salt intake was aggregated by gender and age groups. Replacing salt with umami substances could help UK adults reduce daily salt intake by 9.09%-18.59% (9.21%-18.43% for women; 8.83%-19.43% for men), which is equivalent to 0.45-0.92 g/day of salt reduction (0.41-0.82 g/day for women; 0.50-1.10 g/day for men). The use of umami substances may serve as one method for the UK government to encourage salt intake reduction, particularly in the context of food product reformulation, as 80% of salt consumed in the country comes from processed foods. Empirical studies with sensory evaluation should be conducted to confirm consumer tolerance. The food industry should also be engaged in conversations regarding the addition of umami to food products in the United Kingdom.

Glutamic acid assisted hydrolysis strategy for preparing prebiotic xylooligosaccharides

Since the immune-boosting properties as well as the benefit of promoting the growth of gut bacteria, xylooligosaccharides as prebiotics have attracted considerable interest as functional feed additives around the world. A growing number of studies suggest that acidic hydrolysis is the most cost-effective method for treating xylan materials to prepare xylooligosaccharides, and organic acids were proved to be more preferable. Therefore, in this study, glutamic acid, as an edible and nutritive organic acid, was employed as a catalyst for hydrolyzing xylan materials to prepare xylooligosaccharides. Further, xylooligosaccharide yields were optimized using the response surface methodology with central composite designs. Through the response surface methodology, 28.2 g/L xylooligosaccharides with the desirable degree of polymerization (2-4) at a yield of 40.5 % could be achieved using 4.5% glutamic acid at 163°C for 41 min. Overall, the application of glutamic acid as a catalyst could be a potentially cost-effective method for producing xylooligosaccharides.

Monosodium glutamate in a type 2 diabetes context: A large scoping review

This scoping review aimed to map and elaborate the heterogenous and inconclusive body of evidence relating monosodium glutamate (MSG) and type 2 diabetes (T2DM). For this reason, multiple health outcomes related to T2DM were included and a systematic search was conducted. Experimental and observational trials between 1995 and January 2021 were collected. The tests were highly heterogenous in their samples, doses, route of exposures, durations, diets and conclusions. There was a pattern of negative effects of MSG at oral doses ≥2,000 mg/kg of body weight, and by gavage or injection at any given dose. Evidence was lacking in many areas and most of the evidence relied on short term tests. Further research should focus on standardizing and justifying methodologies, conducting long term studies and toxicokinetic tests, and avoiding bias. Focusing on the gaps highlighted and investigating mechanisms of action of MSG is crucial. Evidence-based toxicology is encouraged.

MONOSODYUM GLUTAMAT, LEZZET ARTTIRICI MI, ÖLDÜREN LEZZET Mİ?

Monosodium glutamat (MSG) 1800’lü yıllardan beri lezzet artırıcı katkı maddesi olarak, işlenmiş ve paketlenmiş tuzlu veya tatlı gıdalarda kullanılmaktadır. Yapılan birçok çalışma MSG kullanımının çok sayıda yapısal ve fonksiyonel bozukluklara yol açabileceğini ortaya çıkarmıştır. Son yıllarda MSG kullanımının çok artması gıda güvenliği konusunda endişelerinde artmasına neden olmuştur.

Directed Evolution and Rational Design of Mechanosensitive Channel MscCG2 for Improved Glutamate Excretion Efficiency

Mechanosensitive amino acid exporters have drawn increasing attention due to their important roles in extracellular accumulation of the target amino acids. Protein engineering is a powerful approach to tailor the properties of amino acid exporters and illustrate structure-function relationships. Here we report the first protein engineering effort on the mechanosensitive glutamate exporter MscCG2 from Corynebacterium glutamicum for improved excretion efficiency of glutamate and understanding of the structure-function relationship. MscCG2 was engineered through directed evolution and computer-assisted design with a coupled assay in microtiter plate format. Improved MscCG2 variants were identified with up to 2.5-fold increase in the level of glutamate excretion in the early stage of fermentation and 1.5-fold in the late stage of fermentation under experimental conditions. Furthermore, the identified variants exhibited enhanced efflux of 4-fluoroglutamate (4-FG), an analog of glutamate. Structure analysis employing homology modeling and molecular dynamics (MD) simulation reveal that identified amino acid substitutions enlarge the size of the seven portals on the equator of MscCG2 and expand the narrowest rim of its inner channel, respectively. This study demonstrates the great potential of protein engineering in improving the secretion efficiency of exporters for enhanced bioproduction.

Spices and Seasoning Mixes in European Union-Innovations and Ensuring Safety

Spices are an important group of food products of great importance in nutrition and food technology. They are mainly used to shape the sensory properties of food in gastronomy, in home cooking, and in industry. Ensuring quality and safety is one of the basic tasks of spice producers. The aim of this review is to present the threats to the consumer related to the presence of spices and seasoning mixes in the diet. Therefore, special attention was paid to such risks as excess sodium chloride (and sodium) in spice mixtures, the use of additives influencing the sensory experience, and irregularities in the labeling of spices and seasoning mixes for the presence of additives and allergens. The threats regarding microbiological safety and the presence of heavy metals, pesticides, plant protection products, as well as synthetic fertilizers and undeclared additives are also presented and the issue of adulteration and lack of authenticity of spices and spice mixtures is discussed. Using data from IJHARS planned inspections and notifications registered in the EU Rapid Alert System for Food and Feed (RASFF) for 2015-2019, as well as the results of own research, an analysis of the risks caused by herbs and spices was carried out. Strategic activities of companies producing spices focus, among others, on improving production and expanding the commercial offer with new, attractive products. The article reviews product and process innovations in spice mixes and the methods of ensuring safety in this group of food products.

Preparation and preliminary quality evaluation of aspirin/L-glutamate compound pellets

L-glutamate is an important component of protein. It can prevent gastrointestinal damage caused by NSAIDs. We constructed two-phase enteric-coated granules of aspirin and L-glutamate compound by extrusion spheronization method and fluidized bed coating. The subliminal effective dose of L-glutamate is 100 mg/kg tested by model of gastric ulcer of rats induced by aspirin and drug administration. HPLC-UV and UV-Vis methods were adopted to determine content and cumulative release of aspirin and L-glutamate as quality analysis method indexes. The prescription and process optimization were carried out with yield, sphericity and dissolution. The two-phase compound granules have good sphericity of 0.93 ± 0.05 (aspirin pellets) and 0.94 ± 0.02 (L-glutamate pellets), content of salicylic acid (0.24 ± 0.03)%, dissolution of aspirin (2.36 ± 0.11)%. Quality evaluation and preliminary stability meet the commercial requirements. The stored environment of compound preparation should be sealed in a cool and dark place.

Effects of the food additive monosodium glutamate on cisplatin-induced gastrointestinal dysmotility and peripheral neuropathy in the rat

BACKGROUND

Cisplatin is an antineoplastic drug known to produce intense vomiting, gastric dysmotility, and peripheral neuropathy. Monosodium glutamate (MSG) is a flavor enhancer with prokinetic properties potentially useful for cancer patients under chemotherapy. Our aim was to test whether MSG may improve gastrointestinal motor dysfunction and other adverse effects induced by repeated cisplatin in rats.

METHODS

Male Wistar rats were exposed or not to MSG (4 g L^-1 ) in drinking water from week 0 to 1 week after treatment. On the first day of weeks 1-5, rats were treated with saline or cisplatin (2 mg kg^-1  week^-1 , ip). Gastrointestinal motility was measured by radiological methods after first and fifth administrations, as well as 1 week after treatment finalization. One week after treatment, the threshold for mechanical somatic sensitivity was recorded. Finally, samples of stomach, terminal ileum and kidneys were evaluated in sections using conventional histology. The myenteric plexus was immunohistochemically evaluated on distal colon whole-mount preparations.

KEY RESULTS

Monosodium glutamate prevented the development of cisplatin-induced neuropathy and partially improved intestinal transit after the fifth cisplatin administration with little impact on gastric dysmotility. MSG did not improve the histological damage of gut wall, but prevented the changes induced by cisplatin in the colonic myenteric plexus.

CONCLUSION AND INFERENCES

Our results suggest that MSG can improve some dysfunctions caused by anticancer chemotherapy in the gut and other systems, associated, at least partially, with neuroprotectant effects. The potentially useful adjuvant role of this food additive to reduce chemotherapy-induced sequelae warrants further evaluation.

Rationalizing the Role of Monosodium Glutamate in the Protein Aggregation Through Biophysical Approaches: Potential Impact on Neurodegeneration

Monosodium glutamate (MSG) is the world’s most extensively used food additive and is generally recognized as safe according to the FDA. However, it is well reported that MSG is associated with a number of neurological diseases, and in turn, neurological diseases are associated with protein aggregation. This study rationalized the role of MSG in protein aggregation using different biophysical techniques such as absorption, far-UV CD, DLS, and ITC. Kinetic measurements revealed that MSG causes significant enhancement of aggregation of BSA through a nucleation-dependent polymerization mechanism. Also, CTAB-BSA aggregation is enhanced by MSG significantly. MSG-induced BSA aggregation also exhibits the formation of irreversible aggregates, temperature dependence, non-Arrhenius behavior, and enhancement of hydrodynamic diameter. From the isothermal titration calorimetry measurement, the significant endothermic heat of the interaction of BSA-MSG indicates that protein aggregation may be due to the coupling of MSG with the protein. The determined enthalpy change (ΔH) is largely positive, also suggesting an endothermic nature, whereas entropy change (ΔS) is positive and Gibbs free energy change (ΔG) is largely negative, suggesting the spontaneous nature of the interaction. Furthermore, even a low concentration of MSG is involved in the unfolding of the secondary structure of protein with the disappearance of original peaks and the formation of a unique peak in the far-UV CD, which is an attention-grabbing observation. This is the first investigation which links the dietary MSG with protein aggregation and thus will be very instrumental in understanding the mechanism of various MSG-related human physiological as well as neurological diseases.

From the vineyard to the cellar: new insights of Starmerella bacillaris (synonym Candida zemplinina) technological properties and genomic perspective

A large diversity of yeasts can be involved in alcoholic fermentation; however, Starmerella bacillaris strains have gained great attention due to their relevant and particular characteristics. S. bacillaris is commonly known as an osmotolerant, acidogenic, psychrotolerant, and fructophilic yeast. Most strains of this species are high producers of glycerol and show low ethanol production rates, being highlighted as promising alternatives to the manufacture of low-alcohol beverages. The increased production of high alcohols, such as benzyl alcohol that has antifungal and antibacterial properties, highlights S. bacillaris potential as a biocontrol agent. After harvest, antifungal yeasts become part of the must microbiota and may also improve the fermentation process. Moreover, during the fermentation, S. bacillaris releases important molecules with biotechnological properties, such as mannoproteins and glutathione. Considering the potential biotechnological properties of S. bacillaris strains, this review presents an overview of recent trends concerning the application of S. bacillaris in fermented beverages. KEY POINTS: •S. bacillaris as an alternative to the production of low-alcohol beverages. •S. bacillaris strains present biocontrol potential. •Molecules released by S. bacillaris may be of great biotechnological interest.

Thermal stress causes oxidative stress and physiological changes in female rabbits

The present study investigated the effects of heat stress on oxidative stress status and physiological changes using female New Zealand White rabbits. 24 sexually mature female rabbits weighing 1953.1-2375.4 g were divided into 4 groups of 6 animals each and subjected to ambient temperature (T0: 19-26 °C), 27-28 °C for T1, 31-32 °C for T2 and 35-36 °C for T3 using electrical heaters from 8:00 a.m. to 4:00 p.m. daily for 30 days. Feed intake and body weight gain were recorded daily. Behavioral alterations of anxiety, dizziness, aggression, withdrawal, impaired feed intake were observed. At the end of experimental period animals were sacrificed, blood samples and vital organs such as liver, kidney, heart, ovaries, uterus collected for appropriate analysis. Results revealed that animals of T2 and T3 had an 11% decrease in the final body weights and 62% body weight gain but increase in feed conversion ratio by 64.81%, 24.19% water intake, 3.64% in rectal and 2.42% in skin temperature compared to the control. Dizziness, withdrawal to a corner of the cage and reduced feed intake were observed. The live weight of lungs and kidneys increased by 37.71% and 33.78% while that of ovaries and uterus decreased in the same animals of T2 and T3. Animals from T2 and T3 showed significant decrease (p < 0.05) by 23.64% in hemoglobin concentration, 12.73% in red blood cells, 11.93% in packed cell volume, 12.02% in total protein while mean corpuscular volume, white blood cells, lymphocytes, creatinine, urea and aspartate transaminase increased respectively by 10.73%, 42.37%, 15.53%, 28.98%, 53.2% and 23.31% compared to the control. The kidney level of malondialdehyde was significantly increased in T2 and T3 animals by 74.29%, whereas protein, catalase, superoxide dismutase and glutathione peroxidase activity were significantly lower (p < 0.05) compared with control. It was concluded that long-term exposure of female rabbits to elevated ambient temperatures induces heat stress and accompanying oxidative stress that consequently impairs physiological function.

L-Glutamic acid monosodium salt reduces the harmful effect of lithium on the development of Xenopus laevis embryos

Many xenobiotics in the environment affect the human body in various ways. Among those xenobiotics, lithium chloride (Li, LiCl) and monosodium glutamate (L-glutamic acid monosodium salt, MSG) compounds affect the crucial processes of stem cell differentiation, cell proliferation, developmental gene expression, and overall development in animals. In this study, we aimed to examine the developmental effects of exposure to flavor enhancer MSG and LiCI medicament on Xenopus embryos using the frog embryo teratogenesis assay of Xenopus test. To this purpose, Xenopus laevis embryos were exposed to four different concentrations of MSG (120, 500, 750, 1000 mg/dL) and Li (0.02 g/L) alone and in combinations for a period of 96 h, and then normal, abnormal, and death ratios were determined in all exposure groups. Besides, length values of all groups and membrane potentials of fertilized and non-fertilized oocyte groups treated with 120- and 500-mg/dL MSG doses and 0.02-g/L LiCI dose were measured. Treatment with ADI (acceptable daily intake) dose of MSG alone did not lead to a substantial effect on the development of Xenopus laevis embryos. But, exposure to daily doses exceeding the ADI level (500, 750, 1000 mg/dL) caused significant harmful effects. Besides, Li-involving treatments caused dramatic deleterious effects on embryo development. MSG attenuated harmful effects of Li in MSG+Li combined treatments. Membrane potentials of non-fertilized oocytes and fertilized eggs were significantly changed in all groups that their membrane potentials were measured. Extrapolating these results into humans require similarly designed studies conducted on human embryos.

The Salt Flip: Sensory mitigation of salt (and sodium) reduction with monosodium glutamate (MSG) in "Better-for-You" foods

We tested the hypothesis that reduced-salt versions of four "better-for-you" dishes enhanced with monosodium glutamate (MSG) through a "Salt Flip" in an amount that still substantially reduced total sodium matched the consumer acceptance of normal-salt versions. Three versions each-standard recipe with normal salt, reduced salt, and reduced salt with MSG, of four dishes-roasted vegetables (RV), quinoa bowl (QB), savory yogurt dip (SD), and pork cauliflower fried rice (CR) were evaluated by 163 consumers for overall liking and liking of appearance, flavor, and texture/mouthfeel on the nine-point hedonic scale, preference, adequacy of flavor, saltiness, and aftertaste on just-about-right (JAR) scales, likeliness to order, and sensory characteristics by check-all-that-apply. For each dish, the MSG recipe was liked the same (or significantly more for SD, P < 0.05) than the standard recipe, and better than the reduced salt recipe for QB and CR. The same was true of likeliness to order. MSG recipes of QB and SD were significantly preferred to the standard recipes, with no difference for RV and CR. MSG recipes were consistently described as "delicious," "flavorful," and "balanced." Penalty-lift analysis showed that "delicious," "flavorful," "balanced," "fresh," and "savory"; and "bland," "rancid," and "bitter," were positive and negative drivers of liking, respectively. Two of three uncovered preference clusters, accounting for 68% of consumers, consistently liked MSG recipes, and the same or more so than standard recipes. We conclude that MSG can successfully be used to mitigate salt and sodium reduction without compromising consumer acceptance of better-for-you foods. PRACTICAL APPLICATION: The Salt Flip offers a promising dietary sodium reduction strategy through the addition of monosodium glutamate (MSG) to reduced-salt, savory, better-for-you foods that does not compromise consumer acceptance of their sensory profile.

Free L-glutamate-induced modulation in oxidative and neurochemical profile contributes to enhancement in locomotor and memory performance in male rats

Glutamate (Glu), the key excitatory neurotransmitter in the central nervous system, is considered essential for brain functioning and has a vital role in learning and memory formation. Earlier it was considered as a harmful agent but later found to be useful for many body functions. However, studies regarding the effects of free l-Glu administration on CNS function are limited. Therefore, current experiment is aimed to monitor the neurobiological effects of free l-Glu in male rats. l-Glu was orally administered to rats for 5-weeks and changes in behavioral performance were monitored. Thereafter, brain and hippocampus were collected for oxidative and neurochemical analysis. Results showed that chronic supplementation of free l-Glu enhanced locomotor performance and cognitive function of animals which may be attributed to the improved antioxidant status and cholinergic, monoaminergic and glutamatergic neurotransmission in brain and hippocampus. Current results showed that chronic supplementation of l-Glu affects the animal behaviour and brain functioning via improving the neurochemical and redox system of brain. Free l-Glu could be a useful therapeutic agent to combat neurological disturbances however this requires further targeted studies.

Myrtle (Myrtus communis) leaf extract suppresses hepatotoxicity induced by monosodium glutamate and acrylamide through obstructing apoptosis, DNA fragmentation, and cell cycle arrest

A large number of plant extracts have demonstrated to provide health benefits and mitigate several disease conditions. However, at the molecular and cellular levels, few studies have been conducted. The present work was designed to study the effect of Myrtus communis leaf extract (ME) (300 mg/kg bw) against hepatotoxicity induced by monosodium glutamate (MSG) (100 mg/kg bw), and acrylamide (ACR) (20 mg/kg bw) in male rats and determining its molecular and cellular mechanisms. The data showed that the treatment with MSG and/or ACR induced significant changes in numerous biomarkers (Bcl-2 and the programmed cell death protein-1) related to liver damage, as recorded by genotoxicity, apoptosis, and histopathological changes. On the other side, the oral administration of ME (300 mg/kg bw) improved the hepatic conditions as confirmed by the improvement in cell viability, programmed cell death, and histopathological alterations. It can be concluded that the consumption of ME might be useful for minimizing the occurred hepatotoxicity through up-regulation of the key apoptotic regulators as well as the improvement of DNA content and cell cycle restoration. Graphical abstract.

Nutrition and metabolism of glutamate and glutamine in fish

Glutamate (Glu) and glutamine (Gln) comprise a large proportion of total amino acids (AAs) in fish in the free and protein-bound forms. Both Glu and Gln are synthesized de novo from other α-amino acids and ammonia. Although these two AAs had long been considered as nutritionally non-essential AAs for an aquatic animal, they must be included adequately in its diet to support optimal health (particularly intestinal health) and maximal growth. In research on fish nutrition, Glu has been used frequently as an isonitrogenous control on the basis of the assumption that this AA has no nutritional or physiological function. In addition, purified diets used for feeding fish generally lack glutamine. As functional AAs, Glu and Gln are major metabolic fuels for tissues of fish (including the intestine, liver, kidneys, and skeletal muscle), and play important roles not only in protein synthesis but also in glutathione synthesis and anti-oxidative reactions. The universality of Glu and Gln as abundant intracellular AAs depends on their enormous versatility in metabolism. Dietary supplementation with Glu and Gln to farmed fish can improve their growth performance, intestinal development, innate and adaptive immune responses, skeletal muscle development and fillet quality, ammonia removal, and the endocrine status. Glu (mainly as monosodium glutamate), glutamine, or AminoGut (a mixture of Glu and Gln) is a promising feed additive to reduce the use of fishmeal, while gaining the profitability of global aquaculture production. Thus, the concept of dietary requirements of fish for Glu and Gln is a paradigm shift in the nutrition of aquatic animals (including fish).

Fermentation of high-salt liquid-state soy sauce without any additives by inoculation of lactic acid bacteria and yeast

Food additives are artificial or natural substances that are added to food to improve the color, aroma, taste, and other qualities, and to meet processing requirements. For the concern of food health and safety, brewed soy sauce without additives has attracted consumers' attention. Here, only four necessary raw materials including soybean, wheat, salt, and water were added. High-salt soy sauce fermentation was conducted for six months by sequential inoculation of lactic acid bacteria and yeast under different brine content (18%, 20%, and 22%). By analyzing the physicochemical indicators during moromi, three soy sauces (No. 1: 18% salt, inoculated with Tetragenococcus halophilus and Zygosaccharomyces rouxii, No. 5: 20% salt, inoculated with T. halophilus and Z. rouxii, No. 11: 22% salt, inoculated with T. halophilus and Candida versatilis) were selected and sterilized to produce finished products for further comparative investigation. Results showed that the flavor components of these three soy sauces were richer in variety than the commercial soy sauces and No. 11 soy sauce was detected to have the largest total amount of organic acids. Plate count agar analysis revealed that the free amino acid differences of soy sauces were distinct, among which the No. 11 soy sauce had the highest glutamate content of 19.64 g L^-1. Besides, it was found that the shelf life of these three soy sauces could reach two years at 4 ℃. This study suggests that the high-salt soy sauce made by rational application of lactic acid bacteria, yeast, and effective sterilization can have high quality and long shelf life without adding any additives.

Temporal profile of flavor enhancers MAG, MSG, GMP, and IMP, and their ability to enhance salty taste, in different reductions of sodium chloride

We evaluated the temporal profile of the flavor enhancers monosodium glutamate (MSG), disodium inosinate (IMP), disodium guanylate (GMP), and monoammonium glutamate (MAG). We also evaluated the ability of these flavor enhancers to enhance salty taste in solutions containing different reductions of sodium chloride. Four experiments were conducted using Central Composite Rotational Design (CCRD) with focus on two objectives: concentration of flavor enhancers (0% to 1%) and reduction of sodium chloride content (0% to 100%). A 0.75% saline solution of NaCl was used as a control. In each experiment, the treatments were evaluated by the intensity of salty and umami tastes using an intensity scale. Treatments, selected according to the results of CCRD, were analyzed using time-intensity (TI) and temporal dominance of sensations (TDS) analyses. Glutamates (MSG/MAG) showed greater capacity to enhance salty taste than treatments containing nucleotides (IMP/GMP). The intensity of umami taste, using all the examined flavor enhancers, showed a similar sensory profile. Temporal perception curves (TI and TDS) of salty and umami tastes also showed a similar temporal profile. The glutamic acid amino acids were better able to improve salty taste than nucleotides in any range of sodium chloride reduction. Flavor enhancers showed greater ability to increase salty taste in smaller reductions in sodium chloride content. PRACTICAL APPLICATION: This research expand the knowledge about the ability to enhance the salty taste of flavor enhancers in different reductions in sodium content, Beside that, will provide information about the time profile of flavor enhancers. This study provides scientific technical information on the ability to intensify the salty taste of flavor enhancers and can assist the industry to develop new low sodium products and encourage the scientific community to conduct future research on this subject.

Tetrastigma hemsleyanum Vine Flavone Ameliorates Glutamic Acid-Induced Neurotoxicity via MAPK Pathways

Glutamic acid (Glu) is a worldwide flavor enhancer with various positive effects. However, Glu-induced neurotoxicity has been reported less. Tetrastigma hemsleyanum (TH), a rare herbal plant in China, possesses high medicinal value. More studies paid attention to tuber of TH whereas vine part (THV) attracts fewer focus. In this study, we extracted and purified flavones from THV (THVF), and UPLC-TOF/MS showed THVF was consisted of 3-caffeoylquinic acid, 5-caffeoylquinic acid, quercetin-3-O-rutinoside, and kaempferol-3-O-rutinoside. In vitro, Glu caused severe cytotoxicity, genotoxicity, mitochondrial dysfunction, and oxidative damage to rat phaeochromocytoma (PC12) cells. Conversely, THVF attenuated Glu-induced toxicity via MAPK pathways. In vivo, the neurotoxicity triggered by Glu restrained the athletic ability in Caenorhabditis elegans (C. elegans). The treatment of THVF reversed the situation induced by Glu. In a word, Glu could cause neurotoxicity and THVF owns potential neuroprotective effects both in vitro and in vivo via MAPK pathways.

Brazilian Nutritional Consensus in Hematopoietic Stem Cell Transplantation: Adults

The nutritional status of patients submitted to hematopoietic stem cell transplant is considered an independent risk factor, which may influence on quality of life and tolerance to the proposed treatment. The impairment of nutritional status during hematopoietic stem cell transplant occurs mainly due to the adverse effects resulting from conditioning to which the patient is subjected. Therefore, adequate nutritional evaluation and follow-up during hematopoietic stem cell transplant are essential. To emphasize the importance of nutritional status and body composition during treatment, as well as the main characteristics related to the nutritional assessment of the patient, the Brazilian Consensus on Nutrition in Hematopoietic Stem Cell Transplant: Adults was prepared, aiming to standardize and update Nutritional Therapy in this area. Dietitians, nutrition physicians and hematologists from 15 Brazilian centers thar are references in hematopoietic stem cell transplant took part.

In vitro genotoxicity assessment of monopotassium glutamate and magnesium diglutamate

Food additives are approved chemicals used for various purposes in foods; to provide nutritional safety, increase flavor, extend shelf life, reduce nutrient losses etc. In this study, the in vitro genotoxic effects of flavor enhancers, Monopotassium glutamate (MPG) and Magnesium diglutamate (MDG) were investigated in human peripheral blood lymphocytes by using chromosome aberrations (CAs), sister chromatid exchanges (SCEs), cytokinesis-block micronucleus cytome (CBMN-Cyt), and comet assays. Four concentrations of MPG (125, 250, 500, and 1000 μg/mL) and MDG (93.75, 187.5, 375, and 750 μg/mL) were used. Both food additives significantly reduced mitotic index and increased the frequency of CAs at high concentrations. MPG and MDG (except 93.75 μg/mL) significantly increased SCEs/Cell in concentration-dependent manner. In the CBMN-Cyt test, both MPG and MDG increased the formation of micronucleus, nuclear buds, and nucleoplasmic bridges compared to control in a concentration-dependent manner. However, these increases were statistically significant at higher concentrations. MPG (at 500 and 1000 μg/mL) and MDG (except 93.75 μg/mL) significantly increased DNA damages observed by comet assay. It is concluded from these results that MPG and MDG have clastogenic, mutagenic, aneugenic, and cytotoxic effects, particularly at high concentrations in human lymphocytes in vitro.

Edible mushrooms as a novel protein source for functional foods

Fast demographic growth has led to increasing interest in low-cost alternative protein sources to meet population needs.