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.

Evaluation of Effects of Spray Drying Conditions on Physicochemical Properties of Pomegranate Juice Powder Enriched with Pomegranate Peel Phenolic Compounds: Modeling and Optimization by RSM.

In this study, the effects of pomegranate peel extract concentration (2.5-10%), drying temperature (160-190 °C), and feed flow rate (0.6-1 mL/s) on the properties of pomegranate juice powder enriched with pomegranate peel phenolic compounds and produced by spray drying were investigated. The moisture content, water activity (aw), solubility, water absorption capacity (WAC), hygroscopicity, dissolution time, total phenolic content (TPC), Carr index (CI), Hausner ratio (HR), and brightness (L*) of the samples were evaluated, and the optimal powder production conditions were obtained using response surface methodology (RSM). The results showed that the optimal conditions were found to be the phenolic extract concentration of 10%, the drying temperature of 189.9 °C, and the feed flow rate of 0.63 mL/s, considering the minimization of the moisture content, aw, hygroscopicity, dissolution time, CI, HR, and L*, as well as the maximization of solubility, WAC, and TPC. The effect of the phenolic extract concentration was very significant (p < 0.01) on the WAC, hygroscopicity, dissolution time, TPC, CI, HR, and L* of the powder. Moreover, the effect of the drying temperature was very significant (p < 0.01) on the aw, hygroscopicity, dissolution time, CI, and HR of the powder and significant (p < 0.05) on its moisture content. The effect of the feed flow rate was very significant (p < 0.01) on the solubility, hygroscopicity, and dissolution time of the powder and significant (p < 0.05) on its moisture content. Therefore, we found that the spray drying conditions, such as high temperature, did not negatively affect the content of phenolic compounds in pomegranate powder, and the physical properties of the resulting powder were acceptable. Thus, pomegranate powder enriched with phenolic compounds can be used as a food additive or as a dietary supplement for medicinal use.

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.

Investigating the Probiotic Properties and Antimicrobial Activity of Lactic Acid Bacteria Isolated from an Iranian Fermented Dairy Product, Kashk.

In the present study, kashk samples were collected from two regions of Iran, the Fars (Abadeh) and Razavi Khorasan (Kalat) provinces. Fifteen bacteria were isolated and physiological and biochemical assays were performed. After identification to the genus level, eight isolates were identified as lactic acid bacteria (LAB) and subjected to molecular identification and probiotic properties assays. The results revealed that the isolates were Enterococcus faecium KKP 3772 (KF1), Enterococcus faecium C1 (KF2), Pediococcus pentosaceus H11 (KF3), Pediococcus pentosaceus VNK-1 (KK4), Lactococcus lactis RSg (KK1), Enterococcus faecalis P190052 (KK2), Enterococcus mundtii CECT972T (KK3), and Lactiplantibacillus plantarum PM411 (KK5). Only the numbers of L. lactis RSg (KK1) and Lpb. Plantarum PM411 (KK5) decreased to below 9 Log CFU/mL after acidic conditions (pH = 3) and showed weak antibacterial activity. Enterococcus mundtii CECT972T (KK3) and E. faecium C1(KF2) were highly susceptible to bile salts, while P. pentosaceus VNK-1 (KK4) and P. pentosaceus H11 (KF3) showed the highest resistance. All of the isolates were resistant to tetracycline and sensitive to chloramphenicol and gentamicin. The antimicrobial activity of P. pentosaceus VNK-1 (KK4) and P. pentosaceus H11 (KF3) was higher than other isolates and consequently, their inhibition zones were larger. The adhesion capabilities of LAB isolates to intestinal epithelial cells were evaluated by examining the auto-aggregation factor and cell surface hydrophobicity. The highest and lowest cell surface hydrophobicity and auto-aggregation were obtained from P. pentosaceus VNK-1 (KK4) and E. mundtii CECT972T (KK3), respectively. In general, P. pentosaceus VNK-1 (KK4) and P. pentosaceus H11 (KF3) have shown better probiotic properties as compared to other isolates.

Physicochemical, Pasting, and Thermal Properties of Native Corn Starch-Mung Bean Protein Isolate Composites.

Starch is widely used in food and non-food industries because of its unique characteristics. However, native starch shows some weaknesses that restrict its applications. Recently, some studies have demonstrated the benefits of using protein to overcome these limitations. Therefore, the aim of the present study was to investigate the effect of mung bean protein isolate (MBPI) (2%, 4%, 6%, and 8%) on the physicochemical, pasting, and thermal properties of native corn starch (NCS), as a novel starch-protein composite. Higher swelling power (SP), water absorbance capacity (WAC), and solubility values of NCS were observed with increasing MBPI concentration. Additionally, by the addition of MBPI, the rapid visco analyzer (RVA) showed a reduction in pasting temperature (77.98 to 76.53 °C), final viscosity (5762 to 4875 cP), and setback (3063 to 2400 cP), while the peak viscosity (4691 to 5648 cP) and breakdown (1992 to 3173 cP) increased. The thermal properties of NCS/MBPI gels investigated by differential scanning calorimetry (DSC) showed higher onset, peak, and conclusion temperatures (69.69 to 72.21 °C, 73.45 to 76.72 °C, and 77.75 to 82.26 °C, respectively), but lower gelatinization enthalpy (10.85 to 8.79 J/g) by increasing MBPI concentration. Fourier transform infrared spectroscopy (FT-IR) indicated that the addition of MBPI decreased the amount of hydrogen bonds within starch. Furthermore, after three cycles of freeze-thaw shocks, the syneresis of NCS-MBPI composites decreased from 38.18 to 22.01%. These results indicated that the MBPI could improve the physicochemical properties of NCS, especially its syneresis and retrogradation characteristics.

Investigation of effect of cold plasma on microbial load and physicochemical properties of ready-to-eat sliced chicken sausage.

Sausage may be contaminated with spoilage microorganisms during the processing after cooking and during the chilling process. Non-thermal decontamination such as cold plasma (CP) can be used to prevent the growth of spoilage microorganisms in sausage after packaging. The objective of this study was to investigate the effects of CP on sliced chicken sausage during 60 days of storage. The sausages were divided into three groups: negative control, ultraviolet (UV)-radiated (positive control for 200 and 400 s), plasma (power of 30 and 70 w for 200 and 400 s). The microbial load, pH, color, peroxide value (PV), and textural parameters of the sausages were compared with those of the negative and positive controls. According to the results, total count decreased significantly (p < 0.05) about 1.87 log CFU/g after 400 s of the CP treatment and at the end of storage at 70 w. CP reduced the lightness (L*) and increased redness (a*) more than the UV rays. The PV more increased by UV rather than by plasma. There were no significant changes in pH value and textural parameters after the CP and UV treatments. Although CP more affected some of the physicochemical properties, compared with UV, CP was shown to efficiently inhibit the rapid growth of microorganisms, resulting in a longer shelf-life.

Effect of atmospheric nonthermal plasma on physicochemical, morphology and functional properties of sunn pest (Eurygaster integriceps)-damaged wheat flour.

To improve the quality of sunn pests (Eurygaster integriceps)-damaged wheat flour, the effects of nonthermal plasma on physicochemical, rheological, functional, and microstructural properties were investigated. Gas type (air and oxygen), voltage (22 and 25 volts), and time (0, 2, 4, 6, 8, and 10 min) were the variables of the experiments conducted using a completely randomized design with three replications. The results show that with increasing voltage and time of plasma treatment, the pH decreased significantly (p ≥ .05), and brightness parameter, yellow-blue parameter, water-solubility, water absorption, oil absorption, and swelling power increased significantly (p ≥ .05). The duration of plasma treatment, voltage, and change in input gas from air to oxygen did not significantly change the gluten index, particle size, and negative electric charge of flour particles, and the amount of zeta potential of samples. Differential calorimetric analysis showed the first and second peaks of the thermogram in the range 55-99°C and also 114-99°C. Infrared spectroscopy (FT-IR) showed hydroxyl group, CH bonds, C=O bonds, as well as the presence of types I and II amide bonds in the structure. Microstructural results indicated that plasma treatment reduced the particle size and increased particle sorting. By Increasing voltage and the duration of plasma treatment, peak viscosity, final viscosity, breakdown viscosity, pasting time and temperature significantly increased and setback viscosity decreased (p ≥ .05), which reduced retrogradation which improved the dough stability during the cooling process.

Effects of Mung Bean (Vigna radiata) Protein Isolate on Rheological, Textural, and Structural Properties of Native Corn Starch.

It is critical to understand the starch-protein interactions in food systems to obtain products with desired functional properties. This study aimed to investigate the influence of mung bean protein isolate (MBPI) on the rheological, textural, and structural properties of native corn starch (NCS) and their possible interactions during gelatinization. The dynamic rheological measurements showed a decrease in the storage modulus (G') and loss modulus (G") and an increase in the loss factor (tan δ), by adding MBPI to NCS gels. In addition, the textural properties represented a reduction in firmness after the addition of MBPI. The Scanning electron microscope (SEM) images of the freeze-dried NCS/MBPI gels confirmed that the NCS gel became softer by incorporating the MBPI. Moreover, X-ray diffraction (XRD) patterns showed a peak at 17.4°, and the relative crystallinity decreased with increasing MBPI concentrations. The turbidity determination after 120 h refrigerated storage showed that the addition of MBPI could reduce the retrogradation of NCS gels by interacting with leached amylose. Additionally, the syneresis of NCS/MBPI gels decreased at 14 days of refrigerated storage from 60.53 to 47.87%.

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.

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.

Investigation of decontamination effect of argon cold plasma on physicochemical and sensory properties of almond slices.

Cold plasma is a novel technology for surface decontamination. Almond slices can be contaminated with different microorganisms during their production. In the current research, the atmospheric argon plasma treatment (5, 10, 15, and 20 min) was used to decontamination of almond slices surface. Microbial load, Color, peroxide value, hardness, and sensory properties of slices was comprised with untreated samples (control). Descriptive sensory evaluation about color, flavor, crispiness, crunchiness, and hardness of almond slices were performed. According to the results of the microbial tests, Total count, molds and yeasts, and Staphylococcus aureus of almond surface decreased about 2.95 log cfu/g, 1.81 log cfu/g, and 2.72 log cfu/g after 20 min of plasma treatment, respectively, provided that microbial reduction increased more by increasing the treatment time. Coupled with the color evaluation, peroxide value and sensory attributes didn't change during plasma treatment. Having said that, the hardness of slices was changed by increasing treatment time. Furthermore, Principal Component Analysis and cluster analysis were performed for sensory evaluation. In light of the consumer's point of view, firstly 10 min and secondly 15 min plasma treatment can be more desirable.

Structural, rheological, pasting and textural properties of granular cold water swelling maize starch: Effect of NaCl and CaCl2.

In this study granular cold water swelling (GCWS) starches were subjected to 0, 50, 100, 150 and 200 mM NaCl and CaCl2 and their effects on microstructure, rheological, pasting, and textural properties were determined. SEM images revealed that NaCl decreased the thickness of GCWS starch paste cell walls while, CaCl2 resulted in formation of denser and more homogenous pastes. The atomic force microscopy (AFM) results showed that NaCl increased the surface wrinkles of starch granules but CaCl2 reduced the roughness of starch granule surface. Zeta potential measurements showed both salts reduced the negative values and CaCl2 was more effective than NaCl. The steady shear measurements showed the shear thinning behavior of the samples. Starch pastes incorporated with NaCl had lower consistency coefficient (K) and apparent viscosity. However, the CaCl2 containing samples were more viscous. The pasting and textural parameters were increased by the increase of CaCl2 but decreased with NaCl.

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.

Application of different carbohydrates to produce squash puree based edible sheet.

The production possibility of squash puree-containing edible sheet and its improvement by different hydrocolloids were studied. In this study, two hydrocolloids [carboxymethyl cellulose (CMC) and tragacanth gum] and also one plasticizer (glycerol) were used to produce squash puree-based edible sheets and optimization was performed to produce an edible sheet sample with the optimum properties. The results revealed that the CMC increased the tensile strength, elongation, and water vapor transition (WVT) of the edible sheets, whilst decreased their moisture content. The tragacanth increased the edible sheets elongation, oxygen transition (OT) and opacity. The glycerol also increased the elongation, density, OT, WVT, opacity and water solubility of the edible sheets; whereas the water activity, tensile strength, elastic modulus, and swelling capacity were decreased. The optimum quality of edible sheets was obtained from a combination of 0.14 g of CMC, 0.25 g of tragacanth and 1.88 g of glycerol.

Analysis of different signal peptides for the secretory production of Ama r 2 in gram-positive systems (Lactococcus lactis).

Prokaryotic systems have been considered the most affordable and simplest hosts which are being employed to express recombinant proteins such as allergens; nevertheless, without appropriate signal peptide (SP), these systems cannot be used for secretory proteins. Recently, a lot of effort has been put into assessing the potential of gram-positive strains such as lactic acid bacteria for new applications in the production of heterologous proteins. Ama r 2 is a respiratory allergen from Amaranthus retroflexus, whose recombinant production in the probiotic host could be introduced as a specific and effective way to rapid diagnosis and immunotherapy of this allergy. Consequently, the production of this recombinant protein using the prokaryotic system, requires a suitable SP to protect disulfide bonds and to prevent misfolding. This study was designed to predict the best SPs for the expression of Ama r 2 protein in Lactococcus lactis as the host. In this study, 42 signal sequences were selected from SP databases and the most important features of them were evaluated. First, n, h and c regions of the SPs and their probabilities were investigated by signalP software version 4.1. Then, their physicochemical properties were evaluated by Portparam and SOLpro. Moreover, the secretion sorting and sub-cellular localization sites were evaluated by PRED-TAT and ProtcompB software programs. The results revealed that yjgB, entC2 (Entrotoxine type C-2), ent B (Entrotoxine type), blaZ (Beta lactamase), dex (number 21), blm (Beta lactamase 2), dex (Dextranase; number 20) and number 26 were introduced theatrically as the best SPs to express Ama r 2 in Lactococcus lactis.

Antioxidant potential and antimicrobial activity of chitosan-inulin conjugates obtained through the Maillard reaction.

Chitosan (1%) was glycated with inulin (0.5, 1, and 2%) via the Maillard reaction at various initial pH values (5, 5.5, and 6). Higher pHs led to a greater pH drop and increase in the intermediate products and browning intensity (BI). The chitosan-inulin conjugates were then classified into three levels of low, medium, and high BI through K-means clustering in order to investigate the effect of BI development on the antioxidant and antimicrobial attributes of the conjugates. Covalent linkage between chitosan and inulin was confirmed by fourier transform infrared spectroscopy. High BI chitosan-inulin conjugate had significantly higher antioxidant property compared to chitosan and other conjugate fractions. In addition, the conjugates obtained at low pH values mainly presented greater antimicrobial activities than those prepared at high pHs. It can be concluded that chitosan-inulin Maillard-born conjugates can be used as novel antioxidant and antimicrobial prebiotic-based ingredients for food applications.

Probiotic potential comparison of Lactobacillus strains isolated from Iranian traditional food products and human feces with standard probiotic strains.

BACKGROUND: Traditional fermented products are a rich source of microorganisms which may have remarkable probiotic properties even more significant than probiotic strains of human origin. In this study three Lactobacillus plantarum and one Lactobacillus fermentum strains, isolated from either Iranian traditionally fermented products or children's feces, identified with molecular methods and selected based on high acid resistance, were investigated for their probiotic properties in vitro and compared with standard probiotic strains of the species; L. plantarum ATCC 14917, L. fermentum PTCC 1744 and L. acidophilus ATCC 4356. RESULTS: Most of the isolates showed a high survival rate under gastrointestinal tract conditions and L. plantarum strains displayed a moderate ability to adhere to human colon adenocarcinoma cell line, HT-29. Neutralized cell free culture supernatants of L. plantarum strains were capable of inhibiting pathogens. Almost all of the strains were resistant to vancomycin and streptomycin and susceptible to other clinically relevant antibiotics. Isolated strains exhibited low to moderate autoaggregation (Auto-A), co-aggregation (Co-A) and hydrophobicity, following a strain specific manner. None of the strains invaded into HT-29 cells while strain PF11 could significantly decrease the number of adhering pathogenic bacteria. Most of the strains increased apoptosis of HT-29 cells, though they had no effect on human umbilical vein endothelial cells (HUVECs). CONCLUSION: Favorable probiotic properties of strains PL4 and PF11 along with their anticancer activity imply their potential for clinical or technological applications. However, further in vitro/in vivo investigations are recommended. © 2019 Society of Chemical Industry.