Background and objective: Prebiotics and probiotics intake have been widely recognized in past recent years due to possessing multiple health benefits. Prebiotics are non-digestible carbohydrates that promote the growth and/or activity of beneficial bacteria in the colon which improves the health. Moreover, the incorporation of probiotics in food has also been a growing practice due to its immunomodulatory effect, the production of organic acids and other compounds that promotes the absorption of nutrients and the general health of the digestive system.

Results and conclusion: Biotechnological strategies have been proposed for prebiotic production and purification in order to meet the demand to be included as ingredients in functional food formulation. Different aspects related to the substrates and different fermentation systems for their production as well as the purification and characterization processes are addressed. Also, we will present the benefits promoted by probiotics, the methods of isolation and characterization, as well as the evaluation of these attributes, so that they can be used in the food industry. With the technological developments in prebiotics and probiotics, it will be possible to deliver foods that respond to consumer demand with low cost and with pleasant sensory characteristics as well as providing beneficial health effects.

Conflict of interest: The authors declare no conflict of interest.

Background and objective: Animal processing industry in the EU-28 states, encompassing slaughterhouses, rendering companies, and others, generates high quantities of waste streams containing about 500,000 t of lipids plus considerable amounts of offal material and meat and bone meal. These materials need to be utilized in a value-creating way, such as via bioconversion towards polyhydroxyalkanoate biopolyesters of diverse molecular composition and various plastic-like features. As a novelty, the present article summarizes for the first time previous and current efforts to utilize these animal-based waste streams for polyhydroxyalkanoate production in terms of selection of suitable microbial production strains, upstream processing of the raw material to generate accessible carbon sources, kinetics of the bioprocess, characterization of the produced biopolyesters of diverse molecular architecture, environmental process assessment, and economic feasibility.

Results and conclusion: The compared case studies clearly demonstrate that utilization of animal processing waste as a second generation feedstock for biopolyester production can definitely become an economically viable and sustainable process provided the utilization of optimized microbial strains, tailored feeding regime, short transportation distances, and clear business plans for commercialization of the final products. Most of all, using animal based waste for generation of second generation biopolyesters and second generation biofuel contributes to food security by preserving raw materials of nutritional value.

Conflict of interest: The authors declare no conflict of interest.

Background and objective: β-galactosidase enzymes hydrolyze lactose into glucose and galactose for production of lactose free dairy products. However, different ions and fat content in milk may act as the inhibitor or activator for β-galactosidase enzymes. A cold-active β-galactosidase enzyme (BGalP), originally from Planococcus sp. L4, was previously expressed in Pichia pastoris to perform lactose hydrolysis in the refrigerated milk. In this study, the effects of milks major ingredients were evaluated on the enzymatic kinetics to confirm its capacity for hydrolyzing milk lactose.

Material and methods: The activity was determined in different concentrations of NaCl, KCl, MgCl_2, and CaCl₂ as well as in the milk with low, medium or high-fat content. In these experiments ortho-Nitrophenyl β-galactoside was used as the substrate. Additionally, glucose was measured as the product after incubation of milk with BGalP enzyme for 24 h at room temperature.

Results and conclusion: This study demonstrated that ions and fat content did not adversely affect the enzyme activity in the concentration corresponding to the milk contents. Ca (27.5-32.5 mM), Cl (25.3-30.9 mM), Na (15.2-39.1 mM) and Mg (3.75-5.83 mM) had no inhibitory effects, but KCl decreased the enzyme activity. Since Cl existed in MgCl_2, and CaCl₂ exerted no inhibitory effects, it can be concluded that inhibitory effects of KCl resulted from potassium rather than chloride. The results indicate that BGalP enzyme was not inhibited by milks major ingredients and has the potential to be used for the production of lactose-free dairy products.

Conflict of interest: The authors declare no conflict of interest.

Background and objective: Presently, there is a growing interest in food produced without the addition of chemical preservatives. Lactic acid bacteria have a high potential to control the growth of undesirable microorganisms. In this work, the antifungal activity of eight strains of lactobacilli isolated from plant sources and foodstuffs (tartar sauce, wheat flour, barley flour, sourdough) were tested against Fusarium culmorum DMF301 and Penicillium expansum DMF04.

Materials and methods: Antifungal activity of live cells of lactobacilli and their heat-treated supernatants was determined by agar diffusion method at 30°C, the radial growth of fungi was measured. Organic acid production of tested strains was examined by HPLC.

Results and conclusion: Live cells of three Lactobacillus plantarum strains showed the highest antifungal activities. Fusarium culmorum DMF301 was more sensitive to the activity of lactobacilli. Heat-treated bacterial supernatants (100°C, 10 min) were also tested, being added at 10 or 20% v v^-1 to the culture medium; growth of Fusarium culmorum DMF301was inhibited by range of 80-90% compared to controls at 10% supernatant concentration and fully at 20%. However, after neutralization, only the heat treated supernatant from Lactobacillus plantarum CCDM 583 had partially effective antifungal activity. The mutual inhibition of lactobacilli strains reduced their antifungal activity. Statistically significant differences in activity against Fusarium culmorum DMF 301 were found using individual strains of Lactobacillus plantarum CCDM 583 and MP2 or their combination. For use in combination with other cultures, it is therefore necessary to verify the compatibility of various strains of lactobacilli.

Conflict of interest: The authors declare no conflict of interest.

Background and objective: A Spirulina platensis is one of the major sources of functional food ingredients with nutraceutical properties. It is a very perishable and should be processed immediately after harvesting. Therefore, the main purpose of the present study was investigation the effect of different processing condition on the most important qualitative features of Spirulina platensis.

Material and methods: Fresh Spirulina platensis was processed (shade, sun, oven, microwave, vacuum oven, freeze and spray-drying and freezing with and without blanching) and changes in its qualitative characteristics (minerals and fatty acids composition, total phenolic compounds and antioxidant activity) of samples were analyzed.

Results and conclusion: Processing conditions significantly (p≤0.05) affected the qualitative properties of the sample. The vacuum-oven dried sample had the highest level of total phenolic compounds and antioxidant activity because of the lower possibility of oxygen dependent degradation and enzymatic browning reactions. The mineral was not significantly different (p>0.05) in dried samples, while Na, K, Mg, Mn, Ca and P content of the frozen samples were reduced significantly. Various unsaturated essential fatty acids like α-linolenic acid, γ-linolenic acid, arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid were detected in Spirulina. In this regards, spray and freeze-drying were the best processing methods in protecting UFA, and vacuum oven-drying was preferred in protecting total phenolic compounds and antioxidant activity of the Spirulina platensis.

Conflict of interest: The authors declare no conflict of interest.

Background and objective: Gamma-aminobutyric acid is a non-protein amino acid produced by lactic acid bacteria in fermented foods and includes unique functions in the human biological system. The aim of this study was optimization of culture media for gamma-aminobutyric acid production in probiotics extracted from local dairy products in west of Iran using two culture media of MRS broth and whey protein.

Material and methods: The potential of gamma-aminobutyric acid production was assessed in Lactobacillus paracasei, Lactobacillus plantarum and Pediococos acidilactici, respectively extracted from doogh, yogurt and cheese using MRS broth and whey protein media and high performance liquid chromatography. To increase gamma-aminobutyric acid production, these media were optimized as pH (4-6), temperature (30-50°C), time (12-72 h) and glutamic acid concentration (25-250 mM).

Results and conclusion: Results have shown that Lactobacillus plantarum extracted from doogh includes the highest potential of gamma-aminobutyric acid production (115.24 mg kg^-1) under the following conditions of a culture temperature of 37°C, incubation time 60 h at pH 5 in MRS broth containing 50 mM of glutamic acid. After optimization of Lactobacillus plantarum media, gamma-aminobutyric acid production increased to 170.492 mg kg^-1. The optimum conditions included a glutamic acid concentration of 250 mM, culture temperature at 37.27°C, pH=5.19 and an incubation time of 72 h. Based on the results, use of local isolated dairy products in west region of Iran and optimization of growth conditions increased the ability of gamma-aminobutyric acid production.

Background and objective: Production of single cell protein has various outstanding advantages, e.g., it can be grown on waste and it is environmental friendly as it helps in upgrading agricultural wastes. In the present study, the influence of process parameters on the biomass formation (g l^-1), protein production (% w w^-1) and volumetric productivity (g l^-1 h^-1) of Fusarium venenatum IR372C was determined.

Material and methods: The Vogel medium was used with glucose as the carbon source for pre culture cultivation and date sugar as the carbon source for production medium. In the first phase of the study, submerged fermentation was conducted in 500 ml flasks and a 3l stirred-tank bioreactor was exploited to conduct the submerged fermentation in the second phase. Plackett-Burman Design with eleven factors, i.e., date sugar concentration, NH₄H₂PO₄, peptone, MgSO₄, KH₂PO₄, temperature, time, shake rate, inoculate age, inoculate size, pH in two levels and Response Surface Methodology with three variables, i.e., date sugar concentration, time and inoculate size were employed to determine the fermentation condition by which the maximum biomass, protein and productivity were achieved.

Results and conclusion: Based on obtained results, by using the selected levels of influencing process variables, a relatively high amount of total protein (ca. 4 g l^-1, 65.3% in the first phase using flasks and 5.5 g l^-1, 76% in the second phase by using the bioreactor, respectively) was achieved. The amino and fatty acid profiles of mycoprotein and its relatively high fiber content (6%) imply that mycoprotein could be incorporated in various types of foods as a functional ingredient.

Conflict of interest All authors have declared that they don’t have any conflict of interest for publishing this research.