فهرست مطالب محمد مهدی قلیان

Stress is a behavioral process that helps humans to increase survival. Stress refers to any biological response to an internal or external stimulator. Stress is difficult to study because of its widespread effect on different parts of the body. A good diet is essential for maintaining mental and physical health. During stress time, eating habits are greatly disrupted and this can cause nutritional deficiencies that may lead to more stress on the body. In stressful situations, the body uses more nutrients than usual. So a good diet is required, as a poor diet causes deficiencies that lead to more stress and health problems. Since 2004, many scientific studies have proven the functional and health-promoting properties of non-living probiotics. In recent years, research has been conducted on the consumption of deactivated cells of probiotics (paraprobiotics) whose positive effects have been proven in some studies. In the current research, lactobacillus plantarum paraprobiotic cells have been used in Shahani grape drinks to reduce stress in master's degree students.

The production of paraprobiotics is done in different ways, including heating, applying ultrasound, ultraviolet radiation, infrared radiation, ionizing rays, applying high hydrostatic pressure, and using some chemical compounds. Each of these inactivation methods cause changes in the structure and functional characteristics of non-living probiotic cells. High-power ultrasound was used for deactivation. the suspension containing parapsychobiotic was evaluated for the amount of the active ingredient gamma-aminobutyric acid using a high- performance liquid chromatography. Inactivated cells were added to the reconstituted Shahani grape juice. 32 healthy students consumed a control drink and a drink containing paraprobiotics daily for 10 weeks during the end-of-semester exams.

The use of paraprobiotics obtained from inactivation methods is useful when the health-giving compounds and metabolites are not completely reduced or destroyed under the influence of the inactivation method. Gamma-aminobutyric acid (GABA) is the most important inhibitory neurotransmitter in the central nervous system and plays an important role in coordinating brain function and reducing anxiety and stress. The results showed that the amount of gamma-aminobutyric acid in the suspension of parapsychobiotics was higher than in the suspension of live bacteria. Subjects who consumed a grape juice drink containing parapsychobiotics had higher general health scores than the control group during exams. The use of paraprobiotics in drinks improved the quality of sleep. At the end of the test, the amount of cortisol in the saliva of the control group was higher than the parapsychobiotic treated group.

The results of this research showed that Lactobacillus plantarum paraprobiotic has potential benefits for improving mental health. Based on the results of this research, paraprobiotics, by affecting the human brain axis, reduce the secretion of stress hormones such as cortisol and, as a result, increase mental stability during the final semester exams of students.

(Clinical Trials Registry Number: IRCT20240128060833N1)

Paraprobiotic is a new group of functional compounds that obtains from the inactivation of a certain probiotics strain. In the present study, the effect of using paraprobiotic Lactobacillus gasseri and storage time (30 days) and temperature (4 and 24 ˚C) on the physicochemical and sensory properties of grape juice was investigated. Grape drink characteristics such as pH, acidity, total soluble solids, turbidity, and sensory attributes were evaluated. The addition of paraprobiotics did not change pH and acidity, and the control specimen (pure grape juice) and the paraprobiotic sample (grape juice containing paraprobiotics) did not differ in this respect. The addition of paraprobiotics increased the turbidity and total soluble solid in the paraprobiotic drink, and these two characteristics also increased with the increase in the storage time.  Considering the sensory properties, the paraprobiotic drink was similar to pure grape juice and had similar overall acceptance scores to pure grape juice, which did not change during storage at different temperatures.

Beer is one of the most consumed beverages worldwide that can be used to transfer probiotics to the host. The aim of this study was to generally review technological parameters incorporated in the production of probiotic beers. Probiotic beer production needs solving technical problems that are linked to processing stages. Although use of probiotics in fermented dairy products has been searched in available scientific literatures, beer is a relatively novel matrix for the incorporation of probiotics and hence a review on its capability as a probiotic carrier can be advantageous. Therefore, objective of the recent review was to investigate the most recent method for the production of probiotic beers. Furthermore, factors affecting the viability of probiotics in the final product were studied.

Scientific literatures verified that probiotic beers could be produced with a few modifications from the non-probiotic beers. As probiotic species include poor growth abilities and probiotic viability is the most important factor considering a product as a probiotic product, multiple criteria for the production of probiotic beers include selecting an alcohol and acid-tolerant probiotic strain, administration of encapsulated probiotics, eliminating thermal and filtration processes, controlling oxygen concentration during fermentation process and after inoculation with probiotic strain, inhabiting severe acidic condition during the probiotic beer production and holding temperature below 5 ˚C during storage and transportation. However, several researches are needed to clarify limiting factors to achieve optimum conditions for the production of appropriate probiotic beers. However, incorporation of nonviable probiotics as alternate germs can be considered as a novel method for the production of health improving beers.

According to the World Health Organization, viable probiotics could have health effects. However, in recent years, many benefits have been observed through application of inactive and non-viable cells of microbes or their metabolites. Therefore, probiotics could be defined as viable, inactive, or non-viable microbial cells or cell extracts that have beneficial health effects on the host. Based on the proposed terminology, probiotics are divided into three categories: real probiotics, pseudo-probiotics, and ghost probiotics. This article reviewed the beneficial effects and underlying mechanisms of inactive and non-viable microbial cells on the host. Also in this article, new proposed terms are described based on the nature of the cell or active ingredient so that it could cover all aspects of the microbial cell (viable, non-viable, inactive, and cell extract).

Production of nutritious drink powders specially based on native or industrial by products is one of the research fields of interests in the food industry. Date syrup as a byproduct of date palm processing is containing a considerable amount of nutritious ingredients and monosaccharides. However this is a little use of this valuable ingredient in the food industry. Whey protein is also one of nutritious and energetic dairy industry byproduct that use of it has been recommended by many food science scientists. In the present study, the effect of concentration of each one of the components include date syrup (0-12%), whey protein concentrate (0-9%) and xanthan stabilizer (0-0/02%) on the phase separation and rheological properties of soft drink by mixture design- extreme vertices were investigated. The results indicated that phase separation deceased with increasing each components specially stabilizer (p<0.05).Generally, increase in components specially stabilizer altered the rheological behavior of soft drink from Newtonian to non-Newtonian.  Also optimization results showed that the phase separation was about 4% in the concentration of 1.49% w/v of xanthan, 8.6% w/v of whey protein and 10.75% w/v date syrup. Optimize formulation had  95 percent of stabilization, consistency index of 0.054 Pa. sn and zeta potential of -34 mV.

It is better to use agricultural by-products or waste for microbial production to reduce costs in the industry. Whey is one of the by-products that are rich in nutrients like vitamins, proteins and essential amino acids. Low-intensity ultrasound stimulation can improve membrane permeability and also help optimize the growth and reproduction of cells. According to high efficiency of Saccharomyces cerevisiae in the fermentation industry, the purpose of this study was to investigate the effect of ultrasound and the use of whey as alternative substrate carbohydrate substrates on the growth of Saccharomyces cerevisiae. PDB medium was formulated by adding a certain amount of dextrose and 1% whey. Ultrasound was applied to the medium containing yeast with three powers (2, 6 and 10 W) at different time periods (10, 20, 30 sec). The amount of cell mass was measured after fermentation process for control and treated samples. Optimum operating conditions obtained from RSM was the power of ultrasound 6 W, sonication time of 20 seconds and Add 10% glucose. Results showed that ultrasonic waves (with a power of 6 kW and 30 seconds) and medium containing whey increased the growth of yeast (from 8/14 to 6/64 mg). Based on the results, the low-power ultrasound can expedite fermentation process up to 4 times, also using nutritious compounds in whey new media could be created to increase fermentation output and prevent possible pollutions. Whey is used as a novel and applied method to enhance the growth of the Saccharomyces cerevisiae, which will ultimately increase the growth efficiency of the microorganisms.

The yeast Saccharomyces cerevisiae has a strong fermentation ability and very high efficiency in the fermented industry and fermented products. There are several ways to increase the growth of the yeast biomass. One of these methods is the use of ultrasound. Stimulating by low intensity ultrasound increased output of enzymes from the cell wall and membrane permeability, it can improve the speed and efficiency of handling the growth and reproduction of cells, and have appropriate applications for yeast growth and single cell protein production. In this study using the yeast Saccharomyces cerevisiae PTCC5269. Optimization of ultrasound power was (2, 6, and 10 watts) and time (10, 20, 30 sec) applied ultrasonic low intensity and low glucose concentrations (5, 10, and 15% v/v) and studied on growth performance, using response surface methodology (RSM). Optimum operating conditions obtained from RSM was the power of ultrasound 6 W, sonication time of 20 seconds and add 10% glucose. Minimum and maximum of produced biomass was 9.1 milligram and 43.3 milligram. Results showed that the dry weight increased with sonication. Maximum amount of yeast biomass obtained after applying average ultrasound power and time. The samples treated with ultrasound shows significant increase in biomass compared with the untreated samples. With increasing cell growth, the conditions being optimal for the use of the yeast Saccharomyces cerevisiae as a single-cell protein due to the probiotic properties of yeast.