Optimization of a gluten-free sponge cake formulation based on quinoa, oleaster, and pumpkin flour using mixture design methodology.

Gluten-free bakery products are the definitive solution for people with celiac disease and gluten sensitivity. In this study, the production of gluten-free sponge cake was optimized using a mixture design methodology. Effects of the amount of ingredients, including quinoa (Chenopodium quinoa) (6-10 g), oleaster (Eleagnus Angustifolia) (1-2 g), and pumpkin powder (Cucurbita moschata) (1-4 g) on the physicochemical characteristics and sensory qualities (color, flavor, cutability, texture, appearance, and overall acceptability) of cakes were investigated. Significant regression models that explained the effects of different amounts of flour on all response variables were determined. The proposed model in this study had high R2 and R2 (adj). Therefore, the model was approved for fitting information. Finally, a gluten-free sponge cake recipe was formulated using 1 g of oleaster flour, 1 g of pumpkin, and 10 g of quinoa flour to achieve the desired sensory quality.

Production of the probiotic dessert containing sprouted quinoa milk and evaluation of physicochemical and microbial properties during storage.

One of the challenges of the food industry is detecting the potential of novel non-dairy food matrices to deliver probiotic bacteria to humans as cholesterol-free products, suitable for people with lactose intolerance and sensitivity to dairy proteins. In this study, the possibility of adding sprouted quinoa milk (SQM) at 0%, 50%, and 100% levels in probiotic non-dairy dessert containing native Lactobacillus plantarum isolated from camel milk was investigated. Physicochemical, functional, microbiological, color, texture, and organoleptic characteristics of probiotic dessert samples were evaluated during 1, 7, and 14 days of storage at 4°C. According to the results, fat, protein, carbohydrates, and ash increased significantly during germination (p < .05). With boosting the SQM levels in the probiotic desserts, the number of soluble solids increased, and the syneresis decreased significantly (p < .05). The simultaneous increase in SQM levels and time caused an increase in acidity and decreased the moisture content of the samples. As the storage time increased, the intensity of the syneresis also decreased. The brightness index in all samples containing SQM was lower than in the control sample. During storage, the viable cell number of Lactobacillus plantarum in all samples decreased significantly. However, they were above the minimum required for FDA recommendation (6 log CFU g-1), varying from 4.6 × 108 CFU/mL to 4.3 × 107 CFU/mL for 50% SQM treatment. It was concluded that probiotic desserts containing SQM up to 50% could be properly presented in the market as gluten-free and functional food products.

Physicochemical and Sensory Properties of Vegan Gummy Candies Enriched with High-Fiber Jaban Watermelon Exocarp Powder.

The customer demand for healthier, fortified, and vegan products has recently received much attention. In this study, the vitamin C content, total phenolic compounds, total flavonoid, and anthocyanin, as well as the antioxidant activity of Jaban watermelon exocarp (JWE) powder were first investigated. Then, the gummy candies (GCs) were prepared with different concentrations of JWE powder (20, 35, and 50%), citric acid (0.75 and 1%), and agar gum (0.5 and 1%), and their physicochemical and sensory properties were evaluated. The results showed that the moisture content and water activity of GCs decreased, while the pH value increased with the increasing concentration of JWE powder. Moreover, the GCs became brighter and more yellowish. The rheological and textural analysis indicated that the viscosity and hardness of GCs improved in higher JWE powder levels (0.457 to 1.550 Pa·s and 1667 to 7232 g, respectively). Furthermore, the highest panelists' score was given to the GC 5 sample with 35% JWE powder, 0.75% acetic acid, and 0.5% agar gum.

Effects of adding poly-histidine tag on stability, antimicrobial activity and safety of recombinant buforin I expressed in periplasmic space of Escherichia coli.

The lack of cost-effective methods for producing antimicrobial peptides has made it impossible to use their high potential as a new and powerful class of antimicrobial agents. In recent years, extensive research has been conducted to decrease the cost of recombinant proteins production through microorganisms, transgenic animals, and plants. Well-known genetic and physiological characteristics, short-term proliferation, and ease of manipulation make E. coli expression system a valuable host for recombinant proteins production. Expression in periplasmic space is recommended to reduce the inherently destructive behavior of antimicrobial peptides against the expressing microorganism and to decline susceptibility to proteolytic degradation. In this study, a pET-based expression system was used to express buforin I at E. coli periplasmic space, and its antimicrobial, hemolytic, and cell toxicity activities as well as structural stability were evaluated. The hemolysis activity and cytotoxicity of His-tagged buforin I were negligible and its antimicrobial activity did not show a significant difference compared to synthetic buforin I. In addition, in silico investigating of stability of native and His-tagged buforin I showed that RMSF, RMSD and Rg curves had followed a similar trend during 150 ns simulation. Furthermore, evaluating the modelled structures, FTIR and X-ray methods of both peptides indicated an insignificant structural difference. It was concluded that the recombinant buforin I could be a viable alternative to some currently used antibiotics by successfully expressing it in the pET-based expression system.

The impact of cold plasma innovative technology on quality and safety of refrigerated hamburger: Analysis of microbial safety and physicochemical properties.

Atmospheric cold plasma (ACP) is an innovative non-thermal decontamination technology that is considered a great alternative to conventional preservation methods. Most importantly, improving microbial safety along with maintaining the sensory and quality properties of the treated foods, especially for perishable products. Hence, this study aimed to investigate the antimicrobial effects of novel dielectric barrier discharge (DBD) and Jet cold plasma systems and their impact on the physicochemical, color, and sensory properties of refrigerated hamburger samples. In the current study, hamburger samples were inoculated with Staphylococcus aureus, Escherichia coli, Molds and Yeasts microbial suspension (~106 CFU/mL), and then were treated with argon (Ar), helium (He), nitrogen (N), and atmosphere (Atm) gases at different times (s) (0, 30, 60, 90, 180, 360). Similarly, uninoculated samples were considered for total viable count (TVC) testing. The results exhibited that plasma system type, gas type, and treatment time had a significant antimicrobial effect with a microbial reduction ranging from 0.01 to 2 log CFU/g and 0.04-1.5 log CFU/g for DBD and Jet plasma systems, respectively. Also, a treatment time longer than 90 s for DBD and 180 s for jet resulted in a significant reduction in microbial count. The ability of atmospheric cold plasma to inactivate tested foodborne pathogenic bacteria (E. coli and S. aureus) was stronger than other gases because the concentration of O3 and NO gases in atmospheric plasma is higher than other used plasma gases. Surface color measurements (L*, a* and b*) of samples in both methods (DBD and Jet) were not significantly affected. Moreover, samples treated with various plasma gases have indicated insignificant oxidation changes (Thiobarbituric acid assay). These outcomes can assist to reduce microbial contamination and oxidation of hamburgers as a high-consumption and perishable product using ACP technology. Owing to the non-thermal nature of ACP, samples treated with ACP have exhibited no or least effects on the physical, chemical, and sensory features of various food products. As a result, cold plasma innovative technology can be proposed and used as an efficient preservative method to increase the shelf life of food products.

Effect of zein and zein-Peganum harmala extract coatings of eggshell on the internal quality of eggs and control of Salmonella enteritidis.

The high nutritional value of egg makes it vital to the human diet. Salmonella enteritidis is one of the major global causes of foodborne enteritis in humans. The chicken intestine is the main source of S. enteritidis. Therefore, eggs play an important role in the transmission of salmonellosis. In this study, we evaluated the effectiveness of coatings made of zein either alone or in combination of hydro-alcoholic extract of Peganum harmala on the quality of eggs and control of S. enteritidis at 7°C during a period of 28 days. Results demonstrated that both types of the coating significantly improved the physicochemical properties of eggs including weight loss, Haugh unit, and yolk index compared to controls during storage. However, neither of coatings resulted in significant changes in yolk color and pH (p < 0.05). Both types of coating caused two log CFU/ml reductions in S. enteritidis population from the first day and eliminated the contamination at the end of the experiment (for 28 days). Salmonella elimination occurred at day 21 for zein-plant extract coating. Our findings demonstrate zein coating can be an appropriate approach for maintaining the quality of eggs during shelf life and an effective and economic strategy for control of S. enteritidis in eggs. PRACTICAL APPLICATION: This study shows that the application of zein coating can preserve the internal quality and freshness of eggs during storage. Moreover, zein coating is a highly effective strategy in the control of Salmonella. This method can be used on a commercial scale for enhancing the safety and quality of eggs.

Encapsulation of Lactobacillus acidophilus in solid lipid microparticles via cryomilling.

We herein delved into the microencapsulation of Lactobacillus acidophilus (LA) into solid lipid microparticles (SLMs) via the cryomilling technique. For this aim, a frozen lipid mixture containing LA was pulverized at different times (7, 14, 21, 28, and 35 min) using a cryogenic mixer mill to produce probiotic-loaded SLMs. The impacts of different cryomilling durations on the SLMs properties (morphology, particle size, water activity, polymorphism, crystallinity, and thermal behavior) and the viability of LA were evaluated. Microencapsulation improved the viability of LA in simulated gastrointestinal fluids, heat stress, and different concentrations of salt and sucrose. SLMs also were suitable to be incorporated into foods. However, once the cryomilling time was prolonged, the viability of encapsulated LA declined, and particle size grew. The cryomilling technique showed great potential as an alternative approach for encapsulation due to the lack of solvent, short processing time, and simplicity.

Buforin I an alternative to conventional antibiotics: Evaluation of the antimicrobial properties, stability, and safety.

Cationic antimicrobial peptides are being developed as a promising class of antimicrobial sub-stances. The introduction of a new antibiotic component requires a comprehensive study of its properties so that it can be relied upon to continue laboratory procedures and clinical trials on laboratory animals or human volunteers. Antimicrobial activity of buforin I was evaluated against 15 of the most important pathogenic bacterial and fungal strains. This was followed by assessing anti-biofilm activity, time-dependent inhibitory, thermal stability, plas-ma stability, hemolysis, and cytotoxic activities. The range of obtained MICs was between 4 and 16 µg/mL. The most resistant and most sensitive microbial strains were S. salivarius and C. perfringens, respectively. Buforin I not only inhibited biofilm formation, but also showed a high biofilm radiation activity. Buforin I was stable in human plasma and also at different temperatures including 40, 60, and 80 °C. Although no significant anti-cancer properties were observed for buforin I, the lack of cytotoxicity as well as the lack of hemolytic activity confirm its safety. The high therapeutic index indicated that buforin I has a considerable pharmaceutical potential and can be a reasonable candidate to replace antibiotics or administered in combination with antibiotics to increase the effectiveness as well as reduce the dose of antibiotics.

Targeting the ATP Synthase in Staphylococcus aureus Small Colony Variants, Streptococcus pyogenes and Pathogenic Fungi.

The ATP synthase has been validated as a druggable target with the approval of the ATP synthase inhibitor, bedaquiline, for treatment of drug-resistant Mycobacterium tuberculosis, a bacterial species in which the ATP synthase is essential for viability. Gene inactivation studies have also shown that the ATP synthase is essential among Streptococci, and some studies even suggest that inhibition of the ATP synthase is a strategy for the elimination of Staphylococcus aureus small colony variants with deficiencies in the electron transport chain, as well as pathogenic fungi, such as Candida albicans. Here we investigated five structurally diverse ATP synthase inhibitors, namely N,N'-dicyclohexylcarbodiimide (DCCD), oligomycin A, tomatidine, resveratrol and piceatannol, for their growth inhibitory activity against the bacterial strains Streptococcus pyogenes, S. aureus and two isogenic small colony variants, as well as the pathogenic fungal species, C. albicans and Aspergillus niger. DCCD showed broad-spectrum inhibitory activity against all the strains (minimum inhibitory concentration (MIC) 2-16 µg/mL), except for S. aureus, where the ATP synthase is dispensable for growth. Contrarily, oligomycin A selectively inhibited the fungal strains (MIC 1-8 µg/mL), while tomatidine showed very potent, but selective, activity against small colony variants of S. aureus with compromised electron transport chain activity (MIC 0.0625 µg/mL). Small colony variants of S. aureus were also more sensitive to resveratrol and piceatannol than the wild-type strain, and piceatannol inhibited S. pyogenes at 16-32 µg/mL. We previously showed that transposon inactivation of the ATP synthase sensitizes S. aureus towards polymyxin B and colistin, and here we demonstrate that treatment with structurally diverse ATP synthase inhibitors sensitized S. aureus towards polymyxin B. Collectively, our data show that ATP synthase inhibitors can have selective inhibitory activity against pathogenic microorganisms in which the ATP synthase is essential. The data also show that the inhibition of the ATP synthase in Streptococcus pyogenes may be a new strategy for development of a narrow-spectrum antibiotic class. In other major bacterial pathogens, such as S. aureus and potentially Escherichia coli, where the ATP synthase is dispensable, the ATP synthase inhibitors may be applied in combination with antimicrobial peptides to provide new therapeutic options.

Evaluation of the bioprotectivity of Lactobacillus binary/ternary cultures in yogurt.

The attempts toward addition of biocontrol agents in dairy products have gained popularity. Here, we worked on analysing the antifungal activity of binary and ternary combinations of three Lactic Acid Bacteria (LAB) against five spoilage yeasts in yogurt. The yogurt samples were characterized in terms of pH, acidity, WHC, textural parameters, viscosity, survivability and antifungal activity of LAB and sensorial properties during cold storage. The results showed that the inoculation of LAB in yogurt gave rise in significant reduction of pH throughout cold storage while titrable acidity and WHC decreased (p < .05). Inoculation of LAB resulted in significant increase in hardness and adhesiveness while springiness remained constant. On the other hand, apparent viscosity of all samples experienced a profound increase up to the 10th day of storage followed by a reduction trend for the rest of storage period. Analysis of inhibitory activity of LAB showed an efficient barrier against all five yeasts, in which the most activity was recorded for Lactobacillus reuteri followed by Lactobacillus acidophilus. On the other hand, the most resistance yeast was Kluyveromyces marxianus followed by Rhodotorula mucilaginosa. Sensorial analysis revealed that addition of LAB in yogurt brought about a profound improvement in textural quality of samples. Inoculation of LAB cultures in yogurt at 5% (v/v) not only could improve the physicochemical and sensorial properties of yogurt, but also could introduce a strategy toward substituting of chemical preservatives with biocontrol agents.

Evaluation of Antimicrobial Activity of Buforin I and Nisin and Synergistic Effect of the Combination of them as a Novel Antimicrobial Preservative.

One of the most effective methods for increasing the antimicrobial activity of a substance is to combine it with one or more other antimicrobial agents. The aim of the present study was to evaluate the antimicrobial effect of buforin I and nisin alone and investigate the synergistic action of these compounds against the most important food spoilage microorganisms in clouding B. subtilis, S. epidermidis, L. innocua, E. coli, S. Enteritidis, A. oryzae, R. glutinis and G. candidum. The results of MIC and MBC/MFC examinations showed that buforin I had higher antimicrobial activity than nisin on all the microbial strains used in this study (p≤0.5). E.coli was the most resistant to both antimicrobial agents, while Listeria innocua and Staphylococcus epidermidis were the most sensitive to nisin and buforin I, respectively. The results of synergistic interaction between buforin I and nisin indicated that the combination of buforin I and nisin on B. subtilis, S. epidermidis and A. oryzae showed synergistic effect, while it had no effect on S. Enteritidis and Geotrichum candidum. The combination of buforin I and nisin showed partial synergistic effect on Listeria innocua, Escherichia coli, Rhodotorula glutinis. Assessment of viability of the microorganisms under the antimicrobial agents alone and in combination with each other at MICs and FICs indicated that use of these antimicrobial agents in combination enhances antimicrobial activity at lower concentrations of both agents. The present study investigated the antimicrobial properties of buforin I against food spoilage microorganisms for the first time and suggests that its use alone or in combination with nisin may provide a clear horizon for the application of antimicrobial peptides as natural preservatives. Thus, the combination of antimicrobial peptides and traditional antimicrobial food preservative could be a promising option for the prevention of contamination, spoilage, and infestation of food and beverage products.

Evaluation of adherence and anti-infective properties of probiotic Lactobacillus fermentum strain 4-17 against Escherichia coli causing urinary tract infection in humans.

Gastrointestinal (GI) infection is one of the most common types of infectious diseases. Application of probiotic strains in the control of such infections represents a promising approach. In this study, Lactobacillus fermentum strain 4-17 was isolated from kashkineh, an Iranian cereal fermented food, and identified by sequencing its 16S rRNA gene using universal primers. Its probiotic features, including resistance to acid, bile tolerance, antibacterial activity, resistance to intestinal and gastric juices, and hydrophobicity were evaluated. The ability of this strain to adhere to human intestinal cells as well as the anti-adhesive effect of L. fermentum strain 4-17 against E. coli isolated from patients with urinary tract infection was investigated. L. fermentum strain 4-17 was capable of surviving at various conditions such as low pH values, bile salts exposure, and GI tract environment. It showed 43% cell hydrophobicity. The adhesion level of L. fermentum strain 4-17 to human colon adenocarcinoma Caco-2 cells was 8.5% which was also confirmed by scanning electron microscopy (SEM). Furthermore, this strain showed appropriate anti-adhesive properties (including competition, inhibition and replacement properties) against human pathogenic bacteria. These data suggest that L. fermentum strain 4-17 could be examined further for its useful effects and introduced as a novel candidate probiotic to control GI infection disease.

Heterologous expression of Thrombocidin-1 in Pichia pastoris: Evaluation of its antibacterial and antioxidant activity.

The antimicrobial peptide Thrombocidin-1 (TC-1) isolated from human blood that derived from NAP-2 by deleting of two amino acids from C-terminal region. In this study, a C-terminal 6 _ His tagged recombinant TC-1 was expressed as a secreted peptide in Pichia pastoris, for the first time. The recombinant P. pastoris was inoculated in to BMMY culture medium, incubation with 5 µl/ml absolute methanol for 72 h at 30 °C. The TC-1 peptide was concentrated with nickel affinity chromatography and electrophoresis on 16% acrylamide gels. The molecular weight of recombinant TC-1 is approximately 8 kDa and under these conditions, the concentration of TC-1 considered 190 µg/ml that determined by the Bradford method. The antimicrobial activity test (Minimum Inhibitory Concentration and Minimum Bactericidal Concentration) was done against: Listeria monocytogenes, Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeruginosa. The growth of these pathogenic bacteria was limited when we used peptide at a concentration of as low as 19.56 µg/ml. Based on DPPH radical scavenging (DPPH-RS) activity and reducing power assays, this peptide showed relatively good antioxidant potential in comparison with standard antioxidant used in this study (BHT). Due to the existence of TC-1 in blood, which makes it safe for human consumption, and the good results of its antimicrobial and antioxidant activity, it can be introduced as a good alternative and a novel effective peptide to food industry for bio-preservation.

Evaluation of seven different drying treatments in respect to total flavonoid, phenolic, vitamin C content, chlorophyll, antioxidant activity and color of green tea (Camellia sinensis or C. assamica) leaves.

The effect of seven drying treatments (sun, shade, oven 60 °C, oven 80 °C, oven 100 °C, microwave and freeze-drying) were evaluated with respect total flavonoid (TFC), phenolic (TPC), antioxidant activity, vitamin C and color characteristics of green tea. In general, drying increased antioxidant activity, TPC, TFC and chlorophyll content, while it led to a decrease in vitamin C. The highest TPC (209.17 mg Gallic acid/gdw) and TFC (38.18 mg Quercitin/gdw) were obtained in oven drying at 60 and 100 °C, respectively. Among methods, oven drying at 60 °C revealed the highest radical scavenging activity (IC50 = 167.166 µg/ml), while microwave showed the lowest one (IC50 = 505.5 µg/ml). Similar trend was also observed in reducing power assay. The highest vitamin C (16.36 mg/100gDM) and Chlorophyll a (17.35 mg/l) were obtained in freeze drying. Finally, sun and freeze drying methods were considered as the least and the most desirable drying methods, respectively the final color of green tea leaves.