Functional Food Components Research Articles

Comprehensive Dipeptide Profiling and Quantitation by Capillary Electrophoresis and Liquid Chromatography Coupled with Tandem Mass Spectrometry.

Dipeptides have attracted much attention as post-amino acids with physical properties and functions different from those of amino acids. However, a given dipeptide cannot be distinguished by mass spectrometry from its structural isomer with an opposite amino acid binding order unless these isomers are separated before introduction, which complicates the comprehensive analysis of dipeptides. Herein, a novel analytical platform for dipeptide analysis by capillary electrophoresis tandem mass spectrometry and liquid chromatography tandem mass spectrometry is developed. This method is used to quantitate 335 dipeptides and achieves excellent separation of structural isomers with opposite binding orders, high correlation coefficients, and low instrumental detection limits (0.088-83.1 nM). Moreover, acceptable recoveries (70-135%) are observed for most tested dipeptides in chicken liver samples spiked both before and after preparation. The developed method is also applied to the quantitation of dipeptides in the livers of mice fed different diets to detect 236 dipeptides, and the shift from a normal diet to a high-fat diet is shown to increase/decrease (p < 0.05, fold-change < 0.5) the contents of 0/29 dipeptides, respectively. The developed method is expected to facilitate the search for new dipeptide applications such as novel functional components of foods and biomarkers of diseases.

Genetic identification of flax, chia and sesame seeds in processed foods

Chia, sesame and flax seeds are becoming increasingly more frequent components of functional foods because of their proven health benefits. The identification of plant components in complex matrices is generally performed using DNA typing. This method is a fast and economic tool widely applied to assess the genetic origin and authenticity of products from the food supply chain. The aim of this study was to compare two DNA-based methods, quantitative polymerase chain reaction high-resolution melting (qPCR-HRM) and endpoint PCR, used to identify chia, flax and sesame seeds in laboratory-made and commercial products. For this purpose, an endpoint PCR and qPCR-HRM methods were developed. DNA was extracted from chia, sesame and flax seeds, laboratory-made and commercial products. The analysis of flax, chia and sesame melting profiles using HRM post-PCR analysis allowed the identification of chia, sesame and flax in processed foods. The results obtained showed that qPCR-HRM is a cost-effective and efficient method for the identification, authentication and/or detection of seeds in processed food and complex matrices containing chia, sesame and flax.

Immunomodulatory activity of a novel polysaccharide extracted from Huangshui on THP-1 cells through NO production and increased IL-6 and TNF-α expression.

Huangshui (HS), the by-product of Chinese Baijiu, has attracted considerable attention due to its nutrient and microbial composition; however, none of the studies has explored the polysaccharides in HS yet. Here, from HS, we isolated a novel polysaccharide, HSP-3, with an average molecular weight of 26.40kDa. The structure was elucidated based on monosaccharide composition and methylation analysis, NMR, FT-IR, and AFM analysis. It is mainly composed of mannose (46.6%), galactose (17.3%), arabinose (11.2%), glucose (10.5%), xylose (8.2%), fucose (5.2%), and rhamnose (1.0%). The backbone of HSP-3 was made up of→2)-β-d-Manp-(1→2,6)-β-d-Manp-(1→6)-β-d-Galp-(1→3,6)-β-d-Galp-(1→4)-α-l-Rhap-(1→3,4)-α-l-Rhap-(1→. Moreover, stimulation of the production of ROS, NO, TNF-α and IL-6, upregulation of the mRNA and protein expression levels of TNF-α and IL-6 in THP-1 cells, and enhanced the pinocytic and phagocytic capacities of THP-1 cells exhibited significant immunomodulatory properties of HSP-3. Altogether, this study suggests that HSP-3 could be used as an active component in functional foods.

Study on Functional Components of Functional Food Based on Food Vitamins

The research and development of functional food ingredients of food vitamins are gradually moving towards serialization, nutrition, functionalization and standardization, and more and more high-tech applications in this area. In addition to rich basic nutrients (i.e. proteins, fats, sugars, vitamins and minerals), food also contains a wide range of bioactive substances, such as polyphenol compounds, organic sulfur compounds, phytoestrogen terpenoids, etc. At present, the research on functional ingredients of these food sources has become a hot research field in the international academic circle. This paper discusses the meaning of functional foods and their functional ingredients, and expounds the synthesis and extraction of vitamin E. At the same time, the function of compound food fiber in functional food was introduced.

Synergistic Effect of Eugenol and Probiotic Lactobacillus Plantarum Zs2058 Against Salmonella Infection in C57bl/6 Mice.

Previously, we showed the preventive effects of Lactobacillus plantarum ZS2058 (ZS2058) on Salmonella infection in murine models. In this work, we found that eugenol has a selective antibacterial effect, which inhibited Salmonella more than probiotics ZS2058 in vitro. It suggested a synergistic effect of them beyond their individual anti-Salmonella activity. We verified the conjecture in murine models. The results showed that the combination of ZS2058 and eugenol (CLPZE) significantly increased (p = 0.026) the survival rate of Salmonella-infected mice from 60% to 80% and the effect of CLPZE on preventing Salmonella-infection was 2-fold that of ZS2058 alone and 6-fold that of eugenol alone. CLPZE had a synergistic effect on inhibiting ST growth (the coefficient drug interaction ((CDI) = 0.829), reducing its invasiveness (CDI = 0.373) and downregulating virulence genes’ expression in vitro. CLPZE helped the host form a healthier gut ecosystem. CLPZE also elicited a stronger and earlier immune response to systemic infection. In conclusion, these obtained results suggest that ZS2058 and eugenol have a synergistic effect on preventing Salmonella infection and open new perspectives in the strategies of controlling the prevalence of Salmonella by combination of probiotics and functional food components.

Effects of fermented rice bran on DEN-induced oxidative stress in mice: GSTP1, LINE-1 methylation, and telomere length ratio.

N-diethylnitrosamine (DEN), a well-known carcinogen, not only induces excessive reactive oxygen species but also suppresses DNA methylation. This study investigated the effect of fermented rice bran (FRB) treatment on DEN-induced oxidative stress through DNA methylation and telomere length analysis. To evaluate the potential protective role of FRB in oxidative stress, two different doses of FRB, DEN, and their combination were administered to mice that were preadapted or not to FRB. Glutathione-S-transferase P1 (GSTP1) methylation levels significantly decreased at 2 and 24hr after FRB and DEN co-administration in mice with and without pre-adaptation. Moreover, GSTP1 mRNA was upregulated under DEN-induced oxidative stress. Furthermore, changes in long interspersed nuclear element-1 methylation were observed from the viewpoint of genomic instability. In addition, FRB preadapted mice displayed a lower telomere length ratio than the non-adapted mice, suggesting that FRB adaptation offers advantages over the non-adapted conditions in terms of inflammation suppression. PRACTICAL APPLICATIONS: DEN induces excessive ROS, which is associated with oxidative stress on DNA and other cellular components, resulting in inflammation. This study shows that FRB may alleviate DEN-triggered oxidative stress, based on changes in GSTP1, LINE-1 methylation, and telomere length ratios, thereby, revealing the potential of dietary intervention during inflammation. Furthermore, this study furthers the current understanding of DNA methylation mechanisms underlying the antioxidant and anti-inflammatory effects of functional food components. These results indicate that dietary inclusion of FRB may help decrease oxidative DNA damage and its associated inflammation at early stages of a disease.

Effectiveness of probiotics, prebiotics, and prebiotic-like components in common functional foods.

The bioactive ingredients in commonly consumed foods include, but are not limited to, prebiotics, prebiotic-like components, probiotics, and postbiotics. The bioactive ingredients in functional foods have also been associated with beneficial effects on human health. For example, they aid in shaping of gut microflora and promotion of immunity. These functional components also contribute in preventing serious diseases such as cardiovascular malfunction and tumorigenesis. However, the specific mechanisms of these positive influences on human health are still under investigation. In this review, we aim to emphasize the major contents of probiotics, prebiotics, and prebiotic-like components commonly found in consumable functional foods, and we present an overview of direct and indirect benefits they provide on human health. The major contributors are certain families of metabolites, specifically short-chain fatty acids and polyunsaturated fatty acids produced by probiotics, and prebiotics, or prebiotic-like components such as flavonoids, polyphenols, and vitamins that are found in functional foods. These functional ingredients in foods influence the gut microbiota by stimulating the growth of beneficial microbes and the production of beneficial metabolites that, in turn, have direct benefits to the host, while also providing protection from pathogens and maintaining a balanced gut ecosystem. The complex interactions that arise among functional food ingredients, human physiology, the gut microbiota, and their respective metabolic pathways have been found to minimize several factors that contribute to the incidence of chronic disease, such as inflammation oxidative stress.

Spruce Galactoglucomannan-Stabilized Emulsions Enhance Bioaccessibility of Bioactive Compounds

The increasing public awareness of health and sustainability has prompted the development of functional foods rich in health-promoting ingredients. Processing technologies and sustainable multifunctional ingredients are needed for structuring these formulations. Spruce galactoglucomannan (GGM), the main hemicelluloses in softwood cell walls, are an abundantly available, emerging sustainable food hydrocolloid that have the ability to efficiently emulsify and stabilize oil-in-water emulsions. In this study, we illustrate how this lignocellulosic stabilizer affects the digestion of polyunsaturated fatty acids (PUFAs) in vitro. A 100% decrease in the initial TAG content was observed during the in vitro digestion, suggesting that complete hydrolysis of the TAGs was achieved by the digestive enzymes. Besides, no release of mono-, di-, and oligosaccharides or phenolic compounds from GGM was detected. Our results demonstrate that the GGM-stabilized emulsion could potentially deliver lipophilic bioactive ingredients and enhance their bioaccessibility. In addition, this bio-stabilizer itself would remain stable in the upper gastrointestinal track and serve as a prebiotic for gut microbiota. We anticipate GGM to complement or even replace many of the conventional carriers of bioactive components in future health care products and functional foods.

Sea-Buckthorn Flavonoids Alleviate High-Fat and High-Fructose Diet-Induced Cognitive Impairment by Inhibiting Insulin Resistance and Neuroinflammation.

Sea-buckthorn flavonoids (SFs) have been used as functional food components for their bioactive potential in preventing metabolic complications caused by diet, such as obesity and inflammation. However, the protective effect of SFs on cognitive functions is not fully clear. In this study, a high-fat and high-fructose diet (HFFD)-induced obese mice model was treated with SFs for 14 weeks. It was found that the oral SF administration (0.06% and 0.31% w/w, mixed in diet) significantly reduced bodyweight gain and insulin resistance in the HFFD-fed mice. SFs significantly prevented HFFD-induced neuronal loss and memory impairment in behavioral tests. Additionally, SFs also suppressed the HFFD-induced synaptic dysfunction and neuronal damages by increasing the protein expressions of PSD-95. Furthermore, SF treatment activated the ERK/CREB/BDNF and IRS-1/AKT pathways and inactivated the NF-κB signaling and its downstream inflammatory mediator expressions. In conclusion, SFs are a potential nutraceutical to prevent high-energy density diet-induced cognitive impairments, which could be possibly explained by their mediating effects on insulin signaling and inflammatory responses in the brain.

Nutritional profile of Sargassum sp. from Pane Island, Tapanuli Tengah as a component of functional food

Most of The Pane Island Coastal communities are not yet aware of the potential of Sargassum in their coastal area even though its benefits as a foodstuff is quite high, for this reason, it is necessary to have scientific information about the importance of the nutritional content of Sargassum sp. such as proximate chemical composition and crude fibers as a components of functional food product. The proximate chemical composition and crude fibers of Sargassum were studied to understand the nutritional profile. The results show that physical-chemical parameters of waters play an essential role in the nutrients composition of Sargassum. Among the two seaweeds, S. cristaefolium contained highest protein and carbohydrates content (8.54% and 7.25%, respectively) and S. crassifolium possessed highest ash, fat and crude fiber (41.52%, 0.30%, and 24.54%, respectively). Nutrient content and crude fiber in Sargassum cristaefolium and Sargassum crassifolium can be used as components of functional foods.

Genotypic and phenotypic characterization of food-associated Lactobacillus plantarum isolates for potential probiotic activities.

Lactic acid bacterium, Lactobacillus plantarum, has been applied, for centuries, for food and drink fermentations. Given the benefits associated with fermented products, Lb. plantarum strains have captured considerable industrial and scientific interest, so that they are included as fundamental components of functional foods. Indeed, some strains are marketed as probiotics. In the present study, food- and gut-associated Lb. plantarum isolates were genetically characterized by multilocus sequence typing (MLST) and phenotypically characterized for properties that could influence their probiotic potential. MLST and phylogenetic analysis stratified 22 Lb. plantarum isolates into six lineages. The isolates were further phenotypically characterized by an in vitro assay to assess their potential gut community influence via a limited number of assays including acidification activity, strain displacement activity and their intrinsic range of antibiotic resistance. Given growing recognition of the benefits of fermented foods, and the prevalence of Lb. plantarum in these applications, this study highlights analysis of a subset of preliminary important strain-specific features. These features are of interest to all stakeholders, to inform isolate comparison and selection for current functional food associations, and that can serve as a basis for future strain and food-microbe fermentation product development.

Chinese sweet tea (Rubus suavissimus) polyphenols attenuate the allergic responses in a Balb/c mouse model of egg allergy

Abstract The aim of this study was to evaluate the effects of Rubus suavissimus S. Lee extract against hen egg ovalbumin (OVA)-induced allergic response in mice. BALB/c mice were sensitized with OVA via intraperitoneal injection for four weeks and subsequently administered the different doses of Rubus suavissimus S. Lee extract (0.1 0.5 and 1.0% w/v) in drinking water. We demonstrated that Rubus suavissimus S. Lee extract can attenuate OVA allergic response in mice by inducing immune desensitization through Th1/Th2 immunological modulation, a regulatory response involving the transcription factor FOXP3, induction of a suppressed IL-4, but increased IL-10, IL12a and INF-γ, enhanced immunoglobulin isotype IgA production, and suppression of histamine and MMCPT-1. These results suggest that Rubus suavissimus S. Lee extract may be a potentially useful candidate for the design of a functional food component in targeting management of food allergy.

Bound phenolic compounds of whole cereal grains as a functional food component: part two

Since they are eaten regularly, cereals based food make a significant contribution to the daily energy intake, meanwhile in whole-grain form they contribute to higher micronutrients intake that refined cereal products. The bound phenolic compounds, which are accumulated in cereal bran, play a key role in the duodenum, where they are transformed to the absorbable metabolites by microbial fermentation. In part two, an analysis of phenolic compounds is presented, with emphasis on the hydrolysis and extraction procedure for bound phenolic compounds, their quantification and identification. Due to poor bioavailability of non-extractable phenolic compounds, which critically limits the exploitation of their wide potential, the article also discusses techniques and new strategies that enable the release of phenolic compounds from insoluble bound forms during food processing. Two current approaches, germination and fermentation, are presented in more details. With transformation of bound phenolic compounds to more easily accessible free phenolic compounds, we also benefit from their antioxidant and antimicrobial efficacy in addition to a favorable anti-cancer effect on the colon. The awareness of consumers and their demand for healthier foods led to the exploration and incorporation of natural ingredients in the production of value added products. The extraction of ferulic acid from whole grain cereal products and its incorporation in functional food products is definitely an important area of future research.

Bound phenolic compounds of whole cereals grain as a functional food component: part one

Numerous metabolic diseases are nowadays associated with an unbalanced energy-rich diet, depleted from dietary fibers and other protective bioactive compounds. Given the limited success of therapeutic interventions to treat obesity and the metabolic syndrome, there has been an increased interest in other strategies. In part one, the focus is made on a role of whole cereals grain in diet, the most important bioactive components and their distribution in grains. We find out, that bran, a by-product of the grain processing industry, represents an unexploited source of phenolic compounds. Their biosynthesis takes place on the endoplasmic reticulum and other plant organelles from which they are transported to other cellular compartments. Deamination, hydroxylation and methylation are the main reactions involved in the formation of hydroxybenzoic and hydroxycinnamic acids. Special emphasis is made on phenolic compounds which remain in the solid residue after aqueous-organic solvent extraction. Non-extractable phenolic compounds are covalently bound to the cell wall materials, consequently the amount of bioactive compounds in cereals are often underestimated. Ferulic acid, as the most important representative, may acts against disorders related to oxidative stress, including cancer, diabetes and neurodegenerative diseases. Insoluble bound phenolic compounds are not degraded in the digestive tract, they are absorbed into the bloodstream as different metabolites after they are subjected to fermentation by the intestinal microflora. Adequate consumption of bound phenolic compounds can lead to improve antioxidant and anti-inflammatory properties, and there are many evidences suggesting their role in intestinal diseases prevention.

Functional and conformational properties of proteolytic enzyme-modified potato protein isolate.

Potato protein hydrolysates (PPHs) were preparedwith Alcalase on intact potato protein isolates (PPI), with differenthydrolysis times (0.5-4 h), and functional and conformational properties of resultant hydrolysates were investigated. The degree of hydrolysis changed during incubation. Peptide bond cleavage increased and hydrolysis progressed rapidly. Gel electrophoresis showed that, by increasing the hydrolysis time, peptides with an apparent molecular weight below 20 kDa increased. It also revealed that, among potato protein components, patatin was more sensitive to Alcalase® hydrolysis than protease inhibitors. Enzymatic hydrolysis significantly enhanced the solubility and foam capacity of PPHs, but impaired foam stability (P < 0.05). Limited enzymatic hydrolysates (0.5PPH) at the interface improved the emulsion activity and stability index. These emulsions also had the smallest z-average and polydispersity index and showed the highest zeta potential. Fourier-transform infrared spectrometry (FTIR) analysis indicated extensive disruption of hydrogen bonds in PPHs, besides augmentation of α-helices and β-turns, and a decline in the β-sheets in the secondary structure of the PPHs was shown. Potato protein isolate, especially 0.5PPH, has good functional and conformational properties. Overall, our results provide new insights into the use of potato protein hydrolysates as a functional food component in the food industry. © 2019 Society of Chemical Industry.

Oral administration of green tea polyphenols (TP) improves ileal injury and intestinal flora disorder in mice with Salmonella typhimurium infection via resisting inflammation, enhancing antioxidant action and preserving tight junction

Abstract Food and feed contamination caused by Salmonella typhimurium has led to serious economic losses and healthy problems worldwide, including particularly gastroenteritis and diarrheal diseases related to ileal injury and intestinal flora disorder. Tea polyphenols (TP), a class of natural antioxidant food extracted from tea, display multifarious attractive biological activities. The present study was conducted to explore the modulatory effect of TP on intestinal flora disorder in mice with Salmonella typhimurium infection and its underlying mechanisms of alleviating ileal injury. Results showed that TP could markedly alleviate Salmonella typhimurium-induced ileal injury. Meanwhile, inflammation and oxidative stress markers were decreased with an enhancement of antioxidant enzymes and tight junction proteins after TP treatment. Most importantly, TP improves intestinal flora disorder by increasing the antioxidant enzymes activity and tight junction proteins in ileum. Our results may make positive influence on the use of TP as a functional food component with potential therapeutic and preventive utility against ileal injury and intestinal flora disorder induced by Salmonella typhimurium.

Genipin-Aided Protein Cross-linking to Modify Structural and Rheological Properties of Emulsion-Filled Hempseed Protein Hydrogels.

Genipin, a natural electrophilic cross-linker, was applied (5, 10, 20, and 30 mM) to modify hempseed protein isolate (HPI). Genipin treatments resulted in general losses of total sulfhydryls (up to 2.9 nmol/mg) and free amines (up to 77.3 nmol/mg). Surface hydrophobicity decreased by nearly 90% with 30 mM genipin, corresponding to similar tryptophan fluorescence quenching. The genipin treatment converted HPI into highly cross-linked polymers. Hydrogels formed with such polymers when also incorporated with hemp oil emulsions exhibited substantially enhanced gelling ability: up to 3.3- and 2.6-fold increases, respectively, in gel strength and gel elasticity over genipin-untreated protein. The genipin-modified composite gels also exhibited superior water-holding capacity. Microstructural analysis revealed a compact gel network filled with protein-coated oil globules that interacted intimately with the protein matrix when treated with genipin. Such gels remained readily digestible. Hence, genipin-treated hemp protein hydrogels show promise as functional food components.

Combined Buckwheat d-Fagomine and Fish Omega-3 PUFAs Stabilize the Populations of Gut Prevotella and Bacteroides While Reducing Weight Gain in Rats.

Some functional food components may help maintain homeostasis by promoting balanced gut microbiota. Here, we explore the possible complementary effects of d-fagomine and ω-3 polyunsaturated fatty acids (ω-3 PUFAs) eicosapentaenoic acid/docosahexaenoic acid (EPA/DHA 1:1) on putatively beneficial gut bacterial strains. Male Sprague–Dawley rats were supplemented with d-fagomine, ω-3 PUFAs, or both, for 23 weeks. Bacterial subgroups were evaluated in fecal DNA by quantitative real-time polymerase chain reaction (qRT-PCR) and short-chain fatty acids were determined by gas chromatography. We found that the populations of the genus Prevotella remained stable over time in animals supplemented with d-fagomine, independently of ω-3 PUFA supplementation. Animals in these groups gained less weight than controls and rats given only ω-3 PUFAs. d-Fagomine supplementation together with ω-3 PUFAs maintained the relative populations of Bacteroides. ω-3 PUFAs alone or combined with d-fagomine reduced the amount of acetic acid and total short-chain fatty acids in feces. The plasma levels of pro-inflammatory arachidonic acid derived metabolites, triglycerides and cholesterol were lower in both groups supplemented with ω-3 PUFAs. The d-fagomine and ω-3 PUFAs combination provided the functional benefits of each supplement. Notably, it helped stabilize populations of Prevotella in the rat intestinal tract while reducing weight gain and providing the anti-inflammatory and cardiovascular benefits of ω-3 PUFAs.

Effects of sialylated lactulose on the mouse intestinal microbiome using Illumina high-throughput sequencing.

Sialylated oligosaccharides are known to have beneficial effects, such as increasing the level of bifidobacteria, reducing the levels of blood endotoxin and blood ammonia, and enhancing the body's immune system. However, it is unknown whether sialylated lactuloses have modulatory effects on the intestinal microbiota. In this study, 60 healthy mice were randomly divided into six groups, namely, a normal control group, a lactulose group, a Kdn-α2,3-lactulose group, a Kdn-α2,6-lactulose group, a Neu5Ac-α2,3-lactulose group, and a Neu5Ac-α2,6-lactulose group. After 14 days of lactulose administration, the feces of three mice from each group were collected, and the intestinal microbiota were detected by Illumina MiSeq high-throughput sequencing targeting the V3-V4 region of the 16S rDNA gene. At the phylum level, the relative abundance of Firmicutes was increased in the sialylated lactulose groups, while the abundance of Bacteroidetes was decreased. At the family level, sialylated lactulose intervention decreased the relative abundance of Bacteroidales S24-7 group and Helicobacteraceae and enhanced the abundance of Lactobacillaceae, which reflects the modulatory effect of sialylated lactulose on intestinal microbiota. Diversity analysis indicated that the index of Chao was higher in the sialylated lactulose groups than in the normal control group, and the Shannon and Simpson diversity indices were higher in the Kdnα-2,6-lactulose group and the Neu5Ac-α2,3-lactulose group than in the normal control group. The results of the intestinal microbiota sample composition indicated that there were differences between the sialylated lactulose groups and the normal control group. Thus, sialylated lactulose could be used as a functional food component with potential therapeutic applications in manipulating intestinal microbiota to exert beneficial effects on the host's health.

Establishment of a rapid and effective plate chromogenic assay for screening of Aspergillus species with high β-fructofuranosidase activity for fructooligosaccharides production

Fructooligosaccharides (FOS) are commonly regarded as prebiotics and used as components of functional foods. Currently, the industrial sucrose-to-FOS biotransformation is mainly carried out using the microbial-derived β-fructofuranosidases with transglycosylation activity as catalysts. Evaluation of the ability of a microorganism to produce β-fructofuranosidase is commonly conducted by measuring enzyme activity. However, the traditional method requires several steps to identify strains with high β-fructofuranosidase activity, which is not suitable for high-throughput screening. To facilitate screening of a large number of microbial cultures, this study developed a plate chromogenic assay method based on the glucose oxidase (GOD) - peroxidase (POD) bienzymatic system for screening of β-fructofuranosidase-producing fungal strains and predicting their potential to produce FOS. This method used the amount of glucose released from sucrose as indicator to form clear pink halos around the microbial colonies with β-fructofuranosidase activity. Cultivation conditions for the plate assay were optimized as cultivation time 5 h and spore inoculum concentration 108/ml. Moreover, the method was applied to screening of an Aspergillus niger ATCC 20611 mutant library. The mutant A11 displaying the largest pink halo was screened out and its β-fructofuranosidase activity was determined to be 1.65 fold than that of the parental strain. Thin layer chromatography (TLC) assay further indicated that A11 with the largest halo possessed the highest FOS synthesis ability. These results demonstrated the potential of this plate chromogyenic assay method in the rapid and effective identification of excellent FOS producers from a large number of strain samples.