applied food biotechnology
Volume:11 Issue: 1, Winter 2024

The scientific community is currently facing a more than exponential increase of knowledge in all areas and disciplines. In the last 10years, the contribution of the journal Applied Food Biotechnologywas eminent in distributing that knowledge by providing a tribune for researchers from different countries all over the world to share their ideas, observations, and hypotheses. With a focus on different aspects of applied and fundamental biological sciences, the journal Applied Food Biotechnologywas established as a reference of the Iranian scientific community. In the last 10years, the journal has been covering several topics related to exploring the beneficial properties of lactic acid bacteria (LAB) and their role in modern food technologies. LAB are already proven as a realization of Hippocrates' vision for the potential role of food in human and other animals' health. However, what will be the next frontier? What are the challenges in understanding the interactions between microbiota and host microorganisms? What will be the novel analytical tools, facilitating a new era of probiotic research? These were only a few research topics presented and discussed in Applied Food Biotechnologyin the last decade. This editorial overview aims to celebrate the scientific contribution of Applied Food Biotechnologyin the area of research associated with the beneficial properties of LAB, summarizing some of the studies published in the journal.

In this editorial article, nationality of the authors from establishment of Applied Food Biotechnology from 2014to the present time has been overviewed. The editorial board, especially chief editor, wish to make a broad global audience to spread knowledgeof food biotechnology via publication of outstanding articles in this journal.At the beginning of the activityof journal office, a limited number of non-Iranian authors submitted their manuscripts to this journal; however immediately after the publication of the first issue, number of the foreign authors increased further, while they showed their satisfaction with the acceleration in peer-review processes of their manuscripts. From the published articles, probiotics has been the major scope; therefore, screening of the beneficial probiotics from various natural sources and their uses in prevention of diseases have been introduced by various authors. Thus, the most interesting findings of the authors have been introduced; through which, readers are furtheradapted to the journal priorities and preferences in probiotics and postbiotics. It is believed that invitation of prestigious authors and carrying out rapid peer-review processes are a key success to achieve high article citations and authors’ satisfactions.

Lactic acid bacteria are well known as beneficial microorganisms and most of them are probiotic distributed widely, especially in fermented dairy products e.g. yogurt. This study aimed to isolate, characterize and assess antimicrobial effects of lactic acid bacteria producing bacteriocin-like inhibitory substances against foodborne pathogenic bacteria.

In the present study, 17 lactic acid bacteria strains were isolated from 10 commercial yogurt samples and the antibacterial effects of lactic acid bacterial cell culture, cell-free supernatant and neutralized cell-free supernatant was assessed against standard foodborne pathogenic bacteria of Escherichia coli, Listeria monocytogenes, Klebsiella pneumonia and Salmonella typhimurium using agar well diffusion assay. Although various treatments were used, most of the lactic acid bacterial isolates showed antimicrobial activity against the foodborne pathogenic bacteria. Moreover, Lactiplantibacillus pentosus (SY1), Lacticaseibacillus rhamnosus (SY5), Lactiplantibacillus plantarum (SY8) and Lactiplantibacillus plantarum (SY9) showed significantly the best antimicrobial activity against the foodborne pathogens and thus were further identified using 16S rRNA gene molecular method.

Results showed that four isolates could produce bacteriocin-like inhibitory substances, which was significantly effective to inhibit growth of the pathogens. Primary screening for antimicrobial activity showed that 10 lactic acid bacterial strains inhibited Escherichia coli. The results revealed that Listeria monocytogenes and Salmonella typhimurium was inhibited by six and one lactic acid bacterial isolates. Moreover, results showed that Klebsiella pneumoniae was not affected by the isolates or treatment methods. It is concluded that a bacteriocin-like inhibitory substance of lactic acid bacterial isolates was effective; hence, it could be used as a natural food additive to prevent foodborne infections and improve the food quality.

The antihyperglycemic effect is associated with the pre-hispanic fruit xoconostle or tunillo (Stenocereus stellatus, Pfeiffer and Riccobono). This fruit includes in various varieties, distinguished by color. Xoconostle fruits are highly perishable. Therefore, the aim of this study was to assess antihyperglycemic effects of xoconostle juice before (fresh) and after pasteurization. The study focused on the white and red varieties of xoconostle.

In this study, the method involved collecting juice from xoconostle fruits, followed by pasteurization. Chemical, physical and microbial parameters were assessed for the juice and the ability to decrease capillary glucose levels (antihyperglycemic effect) was assessed in male Wistar rats.

Pasteurization process led to decreases in total phenolic content of the red variety of xoconostle fruit, while the white variety showed increases in malic acid content. Despite these changes, fresh and pasteurized juices of the two varieties showed lower blood glucose levels, compared to the control group. Red variety demonstrated a stronger antihyperglycemic effect. In conclusion, pasteurization did not affect pharmacological effects of xoconostle juice, making it a viable preservation method without compromising the antihyperglycemic characteristics. Results of this research suggest aconservation method which preserve the antihyperglycemic effects while extending its shelf life.

Ganoderma lucidum, with its medicinal characteristics, is one of the most beneficial fungi in traditional Asian medicine. This fungus low efficiency of ganoderic acid production has limited its use as a valuable secondary metabolite. Environmental stresses and elicitors such as microbial volatile organic compounds in co-cultures can increase ganoderic acid production. To investigate effects of variables of co-culture time and volume on Ganoderma lucidum growth and ganoderic acid production, Bacillus subtilis and Aspergillus niger were aerially co-cultured with Ganoderma lucidum.

To investigate fungus growth and production of ganoderic acid using bubble column bioreactor, effects of independent variables of temperature, initial inoculation, length-to-diameter ratio (L: D) and aeration were investigated using Taguchi method. Then, effects of co-culture of Ganoderma lucidum with Bacillus subtilis and Aspergillus niger under optimum conditions were investigated.

Optimizing effects of co-culture time and volume variables led to 2.9-fold increases in production of ganoderic acid, compared to the control sample. Optimization of biomass production in the bioreactor showed that biomass production increased significantly by increasing the initial inoculation percentage and temperature. These two variables significantly affected ganoderic acid production and its optimum production point was 10% of initial inoculation, temperature of 25.6 °C, L: D of 4:8 and aeration rate of 0.64 vvm. Gas holdup investigation for air-water and air-fermentation media systems showed that the presence of suspended solids and aeration rate affected gas holdup. Microbial volatile organic compounds in co-culture of microorganisms can increase ganoderic acid production by Ganoderma lucidum. Conflict of interest: The authors declare no conflict of interest.

Glucansucrases from GH70 family are effective transglucosylases, able to use non-carbohydrate acceptors. Glycosylation of flavonoids or terpenoids increases their water-solubility and bioavailability. Enzymatic glycosylation by glucansucrases can be improved by addition of organic solvents to the reaction media. Thus, the aim of the study was to assess effects of menthol, carvacrol and thymol solubilized in organic solvents on the activity of glucansucrase URE 13-300 and transferase reaction.

Several organic solvents were assessed for their effects on glucansucrase activity using DNS method. Kinetic parameters in presence of the most appropriate solvents were evaluated as well. Thymol, carvacrol and menthol were solubilized in DMSO and their effects on the enzyme activity was assessed. Dynamic of oligosaccharides synthesis in aqueous-organic media was investigated using high-performance liquid chromatography.

Maltose-derived oligosaccharides synthesized by glucansucrase URE 13-300 showed degrees of polymerization from 3 to 6 in presence of organic solvents, as well as in presence of buffer alone. Their concentrations did not differ significantly in each of the reactions in aqueous-organic media. Furthermore, kinetic parameters showed adjacent Km values with 5% solvents compared to the control reaction in buffer. These findings revealed that the overall synthesis of glucooligosaccharides was not altered by the organic solvents, nevertheless they changed the product distribution throughout the transferase reactions. These moderate effects of the selected organic solvents were important requirement for the glycosylation of biologically active compounds for use in the food industry.

Meat can be contaminated by Leptospira species. This bacterial pathogen causes severe leptospirosis disease in humans and animals. The major aims of this study were to assess seroepidemiological prevalence of leptospirosis in employees of a slaughterhouse in Guilan Province, Iran, using microscopic agglutination test and further investigate the positive samples using nested polymerase chain reaction method.

In this study, 150 employees of a slaughterhouse in Guilan Province, Iran, were participated after completing written consents and personal questionnaires. This sample size was calculated based on the mean prevalence of the pathogen in the region. After assessing sera of the participants for Leptospira antibody using microscopic agglutination test, urine samples were collected from the positive participant for further assessments using nested polymerase chain reaction.

Based on the results, microscopic agglutination test was positive for 10.7% of the participants. However, Nested-PCR was negative for the positive microscopic agglutination tests on sera collected from the participants with antibodies against Leptospira antigens. The current results demonstrate that Leptospira can occur in asymptomatic humans in slaughterhouses and highlight the high potential of the disease transmission to humans in the province. Therefore, further extended control and prevention measures for slaughterhouse workers are recommended to guarantee the food safety. Conflict of interest: The authors declare no conflict of interest.

Black grass jelly served in sweet syrup is one of the Chinese and East and Southeast Asian traditional beverages. An innovative enrichment can make it a better functional food. This study innovatively enriched the black-jelly food with formulas of probiotic Lactobacillus plantarum Mar8, honey, D-allulose and mangosteen pericarp extract. The probiotic viability, antioxidant and hypoglycemic potential were investigated as well.

Ready-to-drink functional beverages included mangosteen pericarp extract varied in concentrations of 0.1, 0.2 and 0.4 mg ml-1, D-allulose in honey and encapsulated probiotic Lactobacillus plantarum Mar8 in black grass jelly containing konjac and carrageenan. The probiotic viability, antioxidant activity and hypoglycemic potential were the selective parameters for the functional beverage formulas. The viability of probiotic Lactobacillus plantarum Mar8 was assessed using total plate count method. Antioxidant activity was assessed based on the reaction of 2,2-Diphenyl-1-picrylhydrazyl radical scavenging. Hypoglycemic potential was investigated by counting petite yeast cells after treating with black grass jelly formulas. Significant differences were reported using one-way analysis of variance and Duncan's test. Statistically significance included p-values≤0.05.

The probiotic Lactobacillus plantarum Mar8 encapsulated in black grass jelly survived well in the honey, D-allulose and mangosteen pericarp extract formulated beverages. Honey supported the probiotic viability better, producing further antioxidants and high potentials in hypoglycemia than that those of other formulas did. Mangosteen pericarp extract enriched the functionality of the black grass jelly probiotic beverages. However, further studies are needed to assess favorability and stability of this functional food. Conflict of interest: The authors declare no conflict of interest. 

Glucansucrases from GH70 family are effective transglucosylases, able to use non-carbohydrate acceptors. Glycosylation of flavonoids or terpenoids increases their water-solubility and bioavailability. Enzymatic glycosylation by glucansucrases can be improved by addition of organic solvents to the reaction media. Thus, the aim of the study was to assess effects of menthol, carvacrol and thymol solubilized in organic solvents on the activity of glucansucrase URE 13-300 and transferase reaction.

Several organic solvents were assessed for their effects on glucansucrase activity using DNS method. Kinetic parameters in presence of the most appropriate solvents were evaluated as well. Thymol, carvacrol and menthol were solubilized in DMSO and their effects on the enzyme activity was assessed. Dynamic of oligosaccharides synthesis in aqueous-organic media was investigated using high-performance liquid chromatography.

Maltose-derived oligosaccharides synthesized by glucansucrase URE 13-300 showed degrees of polymerization from 3 to 6 in presence of organic solvents, as well as in presence of buffer alone. Their concentrations did not differ significantly in each of the reactions in aqueous-organic media. Furthermore, kinetic parameters showed adjacent Km values with 5% solvents compared to the control reaction in buffer. These findings revealed that the overall synthesis of glucooligosaccharides was not altered by the organic solvents, nevertheless they changed the product distribution throughout the transferase reactions. These moderate effects of the selected organic solvents were important requirement for the glycosylation of biologically active compounds for use in the food industry.

Nowadays, there is a growing interest for use of plant-based products such as extracts in various industrial sectors. Therefore, optimization of conditions for ideal extraction of bioactive compounds is highly important. Olive leaves and fruits include biophenols, which can be used as natural antimicrobial and antioxidant agents. Therefore, extraction of these bioactive compounds can create value-added products, which can be used as natural preservatives in food industries. The aim of this study was to investigate effects of various extraction parameters (type of solvent, solvent volume, temperature, time and pH) on in-vitro antioxidant and antifungal activities of Iranian olive leaf and fruit extracts against five Candida species.

Olive fruit and leaf extracts were achieved using maceration method at various extraction conditions. Antioxidant activity of the prepared extracts was assessed by cupric reducing antioxidant capacity method. The phenolic profile in olive leaf extract was assessed using high performance liquid chromatography. Antifungal activity of the olive leaf extract was assessed using disk diffusion method and minimum inhibitory concentration and minimum fungicidal concentration values.

Results showed that the highest antioxidant activity was recorded in olive leaf extract prepared by 100 ml of 96% ethanol at pH 7 and 80 °C for 6 h. Moreover, HPLC analysis of the ethanolic olive leaf extract showed that oleuropein was the major compound of the extract. Antioxidant activity of the olive leaf extract was higher than that of the fruit extract in various conditions. Regarding antifungal activity, the olive leaf extract showed a higher activity, compared to olive fruit extract at all concentrations. In olive leaf extract, the highest (62.5 µg ml-1) and the lowest minimum fungicidal concentration (15.6 µg.ml-1) values were reported for Candida tropicalis and Candida albicans, respectively. The minimum fungicidal concentration of the olive leaf extract was 250 µg ml-1 for Candida albicans, Candida parapsilosis, Candida glabrata and Candida krusei and 500 µg ml-1 for Candida tropicalis. It can be concluded that olive leaf extract is a source of antioxidant and antifungal substances with potential uses in food industries.

Use of bacterial cellulose has been interested in various industries, especially medical and pharmaceutical industries, due to its unique characteristics, compared to plant cellulose. However, bacterial cellulose production costs have limited its industrial uses, compared to plant cellulose. Decreasing costs of the culture media is one of the effective parameters for the industrial production of bacterial cellulose. This is the first report on combination of vinasse and glucose syrup as a bacterial cellulose culture medium.

Two inexpensive culture media were developed for high-level production of bacterial cellulose based on food industrial wastes of corn steep liquor-glucose and vinasse-glucose syrups. Concentrations of glucose syrup and corn steep liquor as a culture medium and concentrations of vinasse and glucose syrup as another culture medium were optimized using response surface method with central composite design to maximize bacterial cellulose production yields.

Under the optimal conditions after seven days, 14.8 and 13.3 g.l-1 dry bacterial cellulose were achieved in corn steep liquor-glucose syrup and vinasse-glucose syrup respectively. Yield of produced bacterial cellulose from these two cost-effective culture media was one of the highest values reported for bacterial cellulose. Furthermore, the produced bacterial cellulose was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy.

Principles of osmo and thermoanabiosis are used to produce sweetened condensed milks. Regarding their extended shelf lives, there are demands for their export to countries with various climates. However, high-positive and low-negative ambient temperatures during sweetened condensed milks transportation can affect their quality. Hence, it is important to study effects of critical storage temperatures on microbiological, physicochemical and sensory indicators of sweetened condensed milks.

This investigation included a comprehensive study of the physicochemical, microbiological and sensory characteristics of sweetened condensed milks after storage under conditions involving multiple-stage and single-stage temperature changes within various ranges (from 5 to 50 °C; from 5 to -50 °C, from 50 to -50 °C and reverse cycles.).

Analysis of samples subjected to cyclic changes, including multiple-stage heating for 9 d followed by multiple-stage cooling for 11 d, revealed that only viscosity changed relative to the control samples. In the reverse similar cycle (cooling to heating), formation of destabilized fat was observed. Moreover, changes of cycles and subsequent storage of the samples for 6 m led to increased viscosity, compared to control samples. It was established that single-stage freezing with a 14-d storage did not critically affect its quality. In contrast, rapid heating of the sweetened condensed milk up to 50 °C and storage under such critical conditions outside a cooled storage area were unacceptable. Further storage of samples subjected to cycles of single-stage freezing and heating for 6 m demonstrated a complete non-compliance with control samples for all parameters. Thus, sweetened condensed milk can be subjected to single-stage freezing to -50 °C and storage for 14 d, as well as multiple-stage cooling/freezing to -50 °C and multiple-stage heating to 50 °C following by cooling to 5 °C without loss of quality and safety during 6 m.

The researchers are fronting the increasing of knowledge in extraction, application, and also antioxidant and antimicrobial properties of plant extracts and essential oils. In recent decade, the journal "Applied Food Biotechnology" has been established a channel for scientists all around the world to share their own hypotheses, results, and conclusions. As a peer-reviewed multi-disciplinary biotechnological publication, it covers several scopes which one important one is food microbiology. In this context, the journal has published several reports on food application of plant extracts and essential oils. The aim of this text is to determine the main categories of published articles in this context in the Journal of "Applied Food Biotechnology" and so on by editors. It seems that research tend to show the effective function of essential oils, as well as comparison of free and encapsulated forms as antimicrobial and antioxidant agents in food. With the aim of holding the potential to alleviate certain complexities, enhance yield, and simplify the isolation process of bioactive metabolites or their individual components, research has played a significant role in reducing production cost of essential oil and herbal extract.

 Inactivated probiotics provide various health and technological benefits, making them appropriate for the production of functional dairy products. The aim of this study was to investigate effects of adding nonviable probiotics (Lactobacillus acidophilus LA-5 and Lacticaseibacillus casei 431) to doogh (a typical Iranian fermented milk drink).

 Probiotics were inactivated by heat or sonication and added to the samples before or after fermentation. Various parameters such as pH, titratable acidity, redox potential, antioxidant capacity, color, viscosity, and phase separation, viability of traditional starter bacteria and probiotics and sensory characteristics were assessed during fermentation and refrigerated storage at 5 °C.

 Sonicated probiotic-containing treatments included the highest pH decrease rate (0.011 pH min-1) during fermentation, as well as the highest antioxidant capacity (16.45%) and viscosity (35.15 mPa.s), while heat-inactivated probiotic- containing treatments included the lowest viscosity (17.60 mPa.s). Treatments with viable probiotics reasonably included the highest post-acidification rate during storage (4.14 °D d-1), compared to those containing nonviable cells, as well as the minimum phase separation rate. The b* and L* values of color did not differ significantly within treatments, but the highest a* value was observed in the treatments with sonication. The highest populations of Lactobacillus delbrueckii ssp. bulgaricus (log 11,891 cfu ml-1) and Streptococcus thermophilus (log 14,977 cfu ml-1) at the end of the storage were observed in treatments with heated probiotics (compared to viable probiotics) and treatments with sonicated probiotics, respectively. In addition, Lactobacillus acidophilus was more susceptible than Lacticaseibacillus case and included lower viability. Taste, mouth feeling and total acceptance of all samples did not differ significantly within treatments. The present study suggests that inactivated probiotics can successfully be used for the production of fermented milk beverages with appropriate sensory characteristics and higher antioxidant capacity, compared to the control group.

 Use of natural ingredients is a safe efficient approach to overcome various diseases. Encapsulated ginger extract has shown improved physicochemical characterizations, compared with that, the ginger extract has. In this study, a natural system integrated with ginger bioactive compounds (6-gingerol) and green microalgae of Chlorella vulgaris was reported to increase bioactive compounds medicinal effectiveness and introduce a novel food supplement.

 First, nanoparticles of microalgae were produced using ball-milling technique. Ethanolic ginger extract, loaded on microalga nanoparticles, was investigated at various pH values (2-7.4) to effectively release the active agents. Various analytical techniques (e.g., Fourier transform infrared, thermogravimetric analyses) were used to characterize the nanocomposite and investigate its anticancer and antimicrobial effects.

 Dynamic light scattering showed a medium size of 20.9 nm for the microalga nanoparticles. The release assay of ginger polyphenols showed a releasing process controlled by the pH. Fourier transform infrared, thermogravimetric analysis and differential thermal analysis revealed adsorption of ginger extract on nano Chlorella vulgaris surface. Moreover, 2,2-diphenyl-picrylhydrazyl bioassay results on the nanocomposite (GE@nano C.v) verified its significant antioxidant, antibacterial and anticancer activities. The nanocomposite has the minimum inhibitory effect on human breast adenocarcinoma cells and bacterial growth at 1 and 6.25 mg ml-1 concentrations, respectively. In brief, adsorption of ginger extract on the microalga nanoparticle surfaces enhanced physical and chemical characteristics of the ginger extract, compared to its free form. Bioactive compounds in Chlorella vulgaris and ginger extract strengthen their reported activities. Furthermore, microalgal nanoparticles could act as a safe carrier for the controlled release of 6-gingerol in addition to their nutraceutical characteristics.

The objective of this study was to assess antimicrobial effects of silver nanoparticles on Gram-positive and Gram-negative bacteria that used in preparing silver nanocomposite with the antibacterial characteristics using solution method. Moreover, the aim of the current study was to produce antimicrobial silver nanocomposites for food coating with their effects on a wide range of bacteria.

To assess antibacterial characteristics of silver nanoparticles, several steps were carried out. First, nanoparticles were synthesized through a chemical reduction method using NaBH4 and then analyzed using x radiation diffraction, ultraviolet and visible spectroscopic analysis, dynamic light scattering and scanning electron microscopy nanometric assays. Then, Staphylococcus aureus and Escherichia coli were used as Gram-positive and Gram-negative bacterial indicators. Minimum inhibitory concentration, minimum bactericidal concentration and inhibition zone levels were measured. Nanocomposite was produced using solution blending method and its antibacterial characteristics were assessed using inhibition zone method.

Results indicated that silver nanoparticles with 20 and 50 µg.l-1 concentrations included inhibitory effects on Staphylococcus aureus and Escherichia coli, respectively. Furthermore, concentrations of 40 to 60 mg.l-1 included lethal effects on Staphylococcus aureus and Escherichia coli, respectively. Based on the results, the highest antibacterial effects were observed on Gram-positive Staphylococcus aureus. In inhibition zone assays, a 3-5 mm zone was seen around the silver nanoparticle discs in cultures of the microorganisms. In the inhibition zone assay of the produced nanocomposites, the zone was expected regarding the concentrations. Results were calculated in three repetitions and the value estimated through ANOVA was significant when p<0.0001. It has been concluded that silver nanoparticles are useful in Gram-positive and Gram-negative bacteria for the inhibition and destruction. Moreover, it has been verified that using the method includes great effects on antibacterial characteristics of the nanocomposites.