Fermented Functional Foods Research Articles

γ-aminobutyric acid production in skim milk co-fermented with Lactobacillus brevis 877G and Lactobacillus sakei 795

γ-Aminobutyric acid (GABA)-producing Lactobacillus brevis 877G strain isolated from traditional Korean fermented food, kimchi, produced 18.94 mM GABA under 59.13 mM L-monosodium glutamate (MSG). Also, skim milk co-fermented with Lb. brevis 877G as a GABA producer and Lactobacillus sakei 795 as a protease producer resulted in a significant increase in GABA production (22.51 mM) with 29.57 mM MSG. The results indicate that Lb. brevis 877G itself and skim milk cofermented with Lb. brevis 877G and Lb. sakei 795 could be developed to be a useful starter for functional fermented food and dairy food product fortified in GABA.

천연식물추출물을 첨가한 저염 오징어젓갈의 품질특성, 유통기한 및 생리활성

To improve the quality and functionality of the low salt squid Jeot-gal, extracts from three types of medicinal and edible plants (bay leaf, green tea, pine needle) were added. The quality characteristics, bioactivities, and shelf-lives of these preparations were determined at three different fermentation temperatures. The pH decreased more rapidly at higher temperatures, while the amount of volatile basic nitrogen (VBN), total viable cells, and amino nitrogen (NH 2 -N) increased. The shelf-lives of Jeot-gal with natural plant extracts at 10F℃ were 34～35 days, similar to the control. The major free and compositional amino acids of Jeot-gal were glutamic acid, proline, and alanine, while the major nucleotides (and related compounds) were hypoxanthine and inosine. In bioactivity assays, samples supplemented with plant extracts showed higher bioactivities than the control. The DPPH radical scavenging activity of ethanol extracts from Jeot-gal were stronger than the water extracts; in contrast, the water extracts were stronger for hydrogen peroxide scavenging activity. However, superoxide dismutase (SOD)-like activity and β-glucuronidase inhibitory activity were moderately low at 20 mg/mL. Based on sensory evaluation results, the quality of low salt squid Jeot-gal with natural plant extracts is similar to the control. Therefore, low salt squid Jeot-gal with natural plant extracts can be commercialized as a functional fermented food.

The nematode Caenorhabditis elegans as an innovative tool for studying foodborne metabolites and emerging pathogens in the food industry

In the last few decades, various epidemiological evidence has reinforced the concept that diet plays an important role in human health, showing that the type, composition and amount of food consumed can all be linked to the promotion and/or maintenance of a healthy state of being. Traditional fermented functional foods are increasingly being considered healthy and interest in their nutritional and health impact, as well as demand for them, is continuously increasing. Their health benefits are linked to functional microorganisms. These microorganisms may contribute to food functionality exerting a biogenic effect due to the release of active metabolites and bioactive compounds during food processing. Fermented foods are complex and dynamic systems in which microbial populations interact. The technology for production and conservation of foods can influence the development or inhibition of specific bacterial species which are difficult to detect applying the classical microbiological techniques. The nematode Caenorhabditis elegans represents an innovative tool for studying foodborne metabolites and emerging pathogens in the food industry. This free-living nematode provides several practical and experimental advantages, including a short lifecycle, and easy and economic cultivation in large numbers. Some of the characteristics of the C. elegans immune system are conserved in higher eukaryotic organisms. Together with high-performance functional metagenomic and metabolomic analyses, this nematode represents a good model to investigate the potential adverse effects of foodderived microbial bioactive compounds. The information obtained from these studies will open new avenues for the design of innovative biosensors, suitable for specific and rapid bacterial metabolite detection.

Expression, purification, and biochemical properties of arginase from Bacillus subtilis 168

The arginine-degrading and ornithine-producing enzymes arginase has been used to treat arginine-dependent cancers. This study was carried out to obtain the microbial arginase from Bacillus subtilis, one of major microorganisms found in fermented foods such as Cheonggukjang. The gene encoding arginase was isolated from B. subtilis 168 and cloned into E. coli expression plasmid pET32a. The enzyme activity was detected in the supernatant of the transformed and IPTG induced cell-extract. Arginase was purified for homogeneity from the supernatant by affinity chromatography. The specific activity of the purified arginase was 150 U/mg protein. SDS-PAGE analysis revealed the molecular size to be 49 kDa (Trix·Tag, 6×His·Tag added size). The optimum pH and temperature of the purified enzyme with arginine as the substrate were pH 8.4 and 45°C, respectively. The Km and Vmax values of arginine for the enzyme were 4.6 mM and 133.0 mM/min/mg protein respectively. These findings can contribute in the development of functional fermented foods such as Cheonggukjang with an enhanced level of ornithine and pharmaceutical products by providing the key enzyme in arginine-degradation and ornithine-production.

Expression of food-grade phytase in Lactococcus lactis from optimized conditions in milk broth

The major objective of this study was to engineer lactic acid bacteria to produce the enzyme phytase from a gene native to Bacillus subtilis GYPB04. The phytase gene (phyC) of B. subtilis GYPB04 was cloned into the plasmid pMG36e for expression in Lactococcus lactis. The enzyme activity in L. lactis cultured in GM17 broth was 20.25 U/mL at 36°C. The expressed phytase was characterized as active in a pH range of 2.0-9.0 at a temperature range of 20-80°C, with an optimum pH of 5.5-6.5 and temperature of 60°C. When cultured in food-grade milk broth, the transformed L. lactis grew to an OD(600 nm) value of 1.05 and had a phytase yield of 13.58 U/mL. In same broth under optimized conditions for cell growth and phytase production, the transformant reached an OD(600 nm) value of 1.68 and a phytase yield of 42.12 U/mL, representing approximately 1.6-fold and 3.1-fold increases, respectively, compared to growth in natural milk broth. Fermentation was scaled to 5 L under optimized conditions, and product analysis revealed a final OD(600 nm) value of 1.89 and an extracellular enzyme activity of 24.23 U/mL. The results of this study may be used in the dairy fermentation industry for the development of functional, healthy yogurts and other fermented dairy foods that provide both active phytase and viable probiotics to the consumer.

Effect of Synbiotic Interaction of Fructooligosaccharide and Probiotics on the Acidification Profile, Textural and Rheological Characteristics of Fermented Soy Milk

Preparation of yoghurt-like product from non-dairy raw material, such as soy with probiotic and prebiotic is a novel development in the field of fermented functional foods. This research work aimed at finding the new combinations of probiotics Lactobacillus acidophilus, Lactobacillus plantarum and Lactobacillus rhamnosus, which can give good product characteristics to fermented soy milk. Fructooligosaccharide was added in an attempt to reduce the after-taste of soymilk, improve acidification rates and growth of probiotics. Acidification rate was enhanced with L. acidophilus–L. plantarum and L. acidophilus–L. plantarum–L. rhamnosus, resulting in a shorter time to reach pH 4.5. Hardness was significantly (P < 0.05) higher for soy yoghurt fermented by binary co-culture followed by mixed cultures. All the samples showed higher G′ (1,279.70–1405 Pa) and lower tan δ (0.273–0.346) values which signifies firmer and solid-like character of the gel formed by probiotic bacteria. Soy yoghurt made with L. acidophilus–L. plantarum resulted in improved product characteristics with shorter t pH 4.5 (4.28 h). Soy yoghurt fermented with L. acidophilus–L. plantarum showed more than 9 log cfu/ml count which is required for probiotic functional food.

Technological aspects of probiotic functional food development

Fermented food containing live cultures called probiotics are considered as fermented functional foods. Probiotics, when consumed in adequate numbers, provide a health benefit directly or indirectly by production of metabolites to the host. The development of probiotic products is a research priority and challenge for both industry and science sectors due to increasing consumer awareness of their ability to maintain good health along with the supply of essential nutrition. This review presents an overview of probiotic food development, various matrices for probiotic foods, and processing and packaging of probiotic foods.

Production of novel fermented milks

The objective of this research was to test the influence of various natural substances on acid production, growth, and viability of characteristic microorganisms in yogurt and probiotic fermented dairy foods. Oligofructose, inulin, honey, and the dried biomass of Spirulina (Arthrospira) platensis were found to stimulate the growth rate and acid production activity of the major thermophilic diary cultures tested and, in addition to this, the presence of the aforementioned substrates also improved the survival of starter bacteria in fermented milk products during storage. The reduced production time of cultured milks resulted in increased production efficiency. The stimulatory and/or protective effect of oligofructose,inulin, honey, and Spirulina on Bifidobacterium spp. is probably the most important finding of this study because bifidobacteria do not grow well in milk and they have low survival rates in conventional fermented milks. Some of the bioactive substances tested were also capable of exerting an antifungal effect on spoilage yeasts and molds, and improving the nutritional and sensory properties of the final product, thus providing a new opportunity for manufacture of functional fermented dairy foods.

Lactic acid bacteria producing B-group vitamins: a great potential for functional cereals products

Wheat contains various essential nutrients including the B group of vitamins. However, B group vitamins, normally present in cereals-derived products, are easily removed or destroyed during milling, food processing or cooking. Lactic acid bacteria (LAB) are widely used as starter cultures for the fermentation of a large variety of foods and can improve the safety, shelf life, nutritional value, flavor and overall quality of the fermented products. In this regard, the identification and application of strains delivering health-promoting compounds is a fascinating field. Besides their key role in food fermentations, several LAB found in the gastrointestinal tract of humans and animals are commercially used as probiotics and possess generally recognized as safe status. LAB are usually auxotrophic for several vitamins although certain strains of LAB have the capability to synthesize water-soluble vitamins such as those included in the B group. In recent years, a number of biotechnological processes have been explored to perform a more economical and sustainable vitamin production than that obtained via chemical synthesis. This review article will briefly report the current knowledge on lactic acid bacteria synthesis of vitamins B2, B11 and B12 and the potential strategies to increase B-group vitamin content in cereals-based products, where vitamins-producing LAB have been leading to the elaboration of novel fermented functional foods. In addition, the use of genetic strategies to increase vitamin production or to create novel vitamin-producing strains will be also discussed.

Production of Low Fat Yoghurt Enriched With Different Functional Ingredients

Due to a growing demand for functional fermented dairy foods with improved nutritional qualities, the food processing industry has prompted to cut down on ingredients such as fat, sugar and additives, thereby necessitating some important changes in sensory qualities that influence consumer acceptance of fermented dairy products. Addition of functional ingredients such as whey protein concentrate (WPC) and honey may improve overall quality of yoghurt. It is well known ability of WPC to support formation of whey protein aggregates which highly improve physical properties of yoghurt. Honey may be an ideal sweetener for yoghurt due to its sugar concentration, low pH and a variety of beneficial nutritional properties.The aim of the present study was to examine the effect of WPC (1%), as well as combination of WPC and honey (H: 2% and 4%) on the physical and chemical properties of low fat set-style yoghurt during 21 days of storage at 5°C. Yogurt was prepared from milk (1.5% fat), treated on 95ºC for 10 min and yoghurt culture VIVOLAC DriSet Yogurt 442: 10% Lactobacillus delbrueckii subsp. bulgaricus and 90% Streptococcus thermophilus (Vivolac Culture Corporation, Indiana, USA), applying standard manufacturing procedure. It was concluded that the addition of honey in combination with WPC improved quality of produced yoghurt. On the other side, as honey presents a higher nutrition value ingredient, the addition of different percent of honey in combination with WPC could present a novel formulation for functional fermented dairy food.

Natural populations of lactic acid bacteria in douchi from Yunnan Province, China

This research was aimed at isolating and identifying the predominant lactic acid bacteria (LAB) in the traditional Chinese salt-fermented soybean food, douchi, from Yunnan, China. The predominant LAB present were isolated and identified by conventional culture-dependent methods combined with molecular biological methods. Two hundred and sixty isolates were obtained from thirty kinds of traditional fermented douchi from six cities and counties in Yunnan, and those strains were divided into twelve groups by their morphological and biochemical characteristics. Based on 16S ribosomal DNA (rDNA) sequencing and analysis, 56 representative strains were identified as belonging to 6 genera and 14 species: Lactobacillus (4 spp.), Weissella (3 spp.), Pediococcus (2 spp.), Staphylococcus (2 spp.), Enterococcus (1 sp.), and Bacillus (2 spp.). The results show that douchi contains a large natural population of LAB of diverse composition from which some strains could be selected as starters for functional fermented foods. This is the first study on the original douchi from Yunnan, and the results suggest that it may be a useful source for the isolation of LAB. This study has also laid a foundation for further research on developing functional douchi products.

Linoleate isomerase activity occurs in lactic acid bacteria strains and is affected by pH and temperature

To investigate the ability of lactic acid bacteria (LAB) to convert linoleic acid (LA) and α-linolenic acid (α-LNA) to conjugated linoleic acid (CLA) and conjugated linolenic acid (CLNA), respectively. To assess pH and temperature influences on CLA and CLNA production by Lactobacillus sakei LMG 13558. A screening of 48 LAB yielded one Lactobacillus curvatus, five Lactobacillus plantarum and four Lact. sakei strains displaying linoleate isomerase (LAI) activity. CLNA conversion percentages varied largely (1-60%). CLA conversion, occurring in three strains, was lower (2-5%). The LAI gene sequences of the ten LAI-positive strains shared 75-99% identity with the LAI gene sequence of a Lact. plantarum AS1.555. At pH 6.2, CLA and CLNA production by Lact. sakei LMG 13558 was higher at 30°C than at 20 and 25°C. At pH 5.5 (30°C) or 37°C (pH 6.2), LA was not converted and α-LNA only slightly converted. LAB show strain-dependent LAI activity. Production of CLA and CLNA is affected by pH and temperature, as shown for Lact. sakei LMG 13558. Several LAB produce CLA and/or CLNA, as shown for Lact. sakei and Lact. curvatus for the first time. These findings offer potential for the manufacturing of fermented functional foods.

Suitability of ancient and modern cereals to produce novel functional fermented foods with a high content of antioxidant compounds

Suitability of ancient and modern cereals to produce novel functional fermented foods with a high content of antioxidant compounds

Functional Microorganisms for Functional Food Quality

Functional microorganisms and health benefits represent a binomial with great potential for fermented functional foods. The health benefits of fermented functional foods are expressed either directly through the interactions of ingested live microorganisms with the host (probiotic effect) or indirectly as the result of the ingestion of microbial metabolites synthesized during fermentation (biogenic effect). Since the importance of high viability for probiotic effect, two major options are currently pursued for improving it—to enhance bacterial stress response and to use alternative products for incorporating probiotics (e.g., ice cream, cheeses, cereals, fruit juices, vegetables, and soy beans). Further, it seems that quorum sensing signal molecules released by probiotics may interact with human epithelial cells from intestine thus modulating several physiological functions. Under optimal processing conditions, functional microorganisms contribute to food functionality through their enzyme portfolio and the release of metabolites. Overproduction of free amino acids and vitamins are two classical examples. Besides, bioactive compounds (e.g., peptides, γ-amino butyric acid, and conjugated linoleic acid) may be released during food processing above the physiological threshold and they may exert various in vivo health benefits. Functional microorganisms are even more used in novel strategies for decreasing phenomenon of food intolerance (e.g., gluten intolerance) and allergy. By a critical approach, this review will aim at showing the potential of functional microorganisms for the quality of functional foods.

Removal of Cadmium and Lead from Aqueous Solution by Enterococcus faecium Strains

Foods may be contaminated with heavy metals, which, even in small quantities, possess detrimental effects on human health. The aim of the present study was to investigate the uptake of cadmium or lead from an aqueous medium frequently found in foods, by 2 Enterococcus faecium strains (E. faecium EF031 and E. faecium M74). Also, the effects of the bacterial viability, incubation (contact) time, and pH on the binding capacities and binding stability were assessed. The results showed that both of the strains efficiently removed cadmium and lead. While EF031 removed 77.3% to 98.1% of cadmium and 66.9% to 98.9% of lead, M74 removed 53.5% to 91% of cadmium and 42.9% to 93.1% of lead throughout a 48 h incubation period at pH 5. It was found that, at 1 h, EF031 and M74 strains removed cadmium and lead, which was more than 60% of total removed cadmium and lead throughout the whole incubation period of 48 h. It suggests that the uptake of cadmium and lead by EF031 and M74 strains is a rapid process. The binding of both heavy metals increased with increasing pH of an aqueous medium and was the highest at pH 5. Also, the complexes formed between both heavy metals and bacterial cells were found to be stable. These findings indicate that E. faecium strains used in the study are able to bind the 2 heavy metals and may be used in the production of fermented functional foods, which will be healthy via its detoxification properties.

Handbook of Fermented Functional Foods, 2nd edition (2008)

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EVALUATION OF COMMERCIAL PREBIOTIC PRODUCTS ON THE GROWTH OF SELECTED PROBIOTIC BACTERIA STRAINS

The commercial prebiotic in cereal- based products with bovine colostrum, namely Germa-Fit® and Extra-Fit® as culture media for the growth of selected probiotic lactic acid strains (grown separately): L.gasseria and L.rhamnosus were cultured in MRS (control) and commercial prebiotic products. The media were fermented for 48h at 37oC and analysed for viable cell count and changes in pH values. In Germa-Fit® medium, both probiotic lactic acid strains were attained the highest population (9.6 cfu/ml) after 16h of fermentation time (P≤0.05). With the addition of lactose at 0.5, 1.0 and 1.5% the viability of L.gasseria was improved by approximately 2.1, 2.3 and 1.7 log10 cycles respectively, compared to 3.0, 2.3 and 2.5 for L.rhamnosus after 12h of fermentation time. The effect of Extra-Fit® medium was more positive for growth L.gasseria than that of L.rhamnosus after 8-24h of inoculation time. Generally, Germa-Fit® medium in the presence lactose exhibited the highest growth for both prebiotic strains compared to Extra-Fit® and MRS media. The changes in pH of commercial media were in the optimal pH range (4.5-4.4) for growth of lactic acid bacteria. Therefore, this study suggested that the feasibility use of commercial prebiotic products based- cereal with bovine colostrum in the place the widely used MRS for culture media of probiotic lactic acid bacteria to developing new synbiotic functional fermented dairy food products.

Red Yeast Rice Fermentation by Selected Monascus sp. with Deep-Red Color, Lovastatin Production but No Citrinin, and Effect of Temperature-Shift Cultivation on Lovastatin Production

Monascus pilosus NBRC4520 was selected for functional fermented food inoculation for its high lovastatin and low citrinin production with a deep-red color. For koji (mold rice) with high lovastatin production, separation of the growth phase and lovastatin production phase by shifting the temperature from 30 to 23 degrees C increased lovastatin production by nearly 20 times compared to temperature-constant cultivation. In addition, citrinin was not produced even in the lovastatin production phase, although the pigment was increased. With temperature-shift cultivation, 225 microg lovastatin/g dry koji was produced in 14 days without citrinin.

Dried cell-free fraction of fermented milks: new functional additives for the food industry

The claimed health benefits of fermented functional foods are exerted either directly through ingested live microorganisms (probiotics) or indirectly as a result of ingestion of microbial metabolites produced during the fermentation process. Several reports are emerging concerning the immunomodulating capacity of the cell-free fraction of fermented milks. The soluble metabolites present in the whole non-bacterial fraction could be easily spray-dried and added as dried powders to food matrixes whose chemical composition or technological process of manufacture would seriously threaten the viability of probiotic bacteria. The relative technological easiness for incorporating the same biologically active metabolites present in fermented milks, but as a dried cell-free fraction, into other food matrixes opens the doors to the development of a great new variety of functional foods using food matrixes not suitable nowadays for viable probiotic bacteria. The ability to bring functionality to ordinary food through the incorporation of ingredients from natural sources becomes increasingly attractive to the food industry.

Production of γ-aminobutyric acid by Streptococcus salivarius subsp. thermophilus Y2 under submerged fermentation

Gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter in the central nervous system, has several well-known physiological functions and has been applied to the production of many drugs and functional foods. The technology of GABA production via submerged fermentation by Streptococcus salivarius subsp. thermophilus Y2 was investigated in this paper. It indicated that the GABA production was related to the biochemical characteristics of glutamate decarboxylase (GAD) of S. salivarius subsp. thermophilus Y2. After 24 h of fermentation at 37 degrees C, which is the suitable culture conditions for GAD-production, then the culture condition were adjusted to the optimal temperature (40 degrees C) and pH (4.5) for the GAD reaction activity in biotransformation of cells and pyridoxal 5'-phosphate (0.02 mmol/l) were added to the broth at the 48 h, the GABA production was increased up to 1.76-fold, reaching 7984.75 +/- 293.33 mg/l. The strain shows great potential use as a starter for GABA-containing yoghurt, cheese and other functional fermented food productions.