Biochemical Characteristics and Viability of Probiotic and Yogurt Bacteria in Yogurt during the Fermentation and Refrigerated Storage

This research aimed to investigate the viability of probiotic bacteria (Lactobacillus acidophilus LA-5 and Bifidobacterium lactis BB-12) and yogurt bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus) in yogurt during the fermentation, immediately after fermentation and during refrigerated storage (21 d, 4˚C). Also the biochemical characteristics of milk as affected by the commercial 4-strain mixed starter culture were investigated. Storage time affected the viability of all bacterial species. The concentration of lactic acid during the fermentation increased in parallel with the titrable acidity, and the concentration of acetic acid was proportional to the viability of Bifidobacterium lactis. The acetaldehyde level was decreased in the yogurt from day 0 up to the end of the storage. Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus were multiplied considerably during the fermentation. Streptococcus thermophilus could maintain its viability to the highest level, but Lactobacillus delbrueckii ssp. bulgaricus lost its viability rapidly during the cold storage compared to Streptococcus thermophilus. The multiplication and viability of probiotic bacteria were also influenced by the associative strains and species of yogurt organisms. Bifidobacteria counts were satisfactory. The loss of viability for bifidobacteria was gradual and steady during the storage, and they showed good stability during the storage as compared to Lactobacillus acidophilus

Evaluation of coenzyme Q10 addition and storage temperature on some physicochemical and organoleptic properties of pomegranate juice

Today, in parallel to growing in acceptance of functional products, various additives are used to improve the characteristics of functional food products. The coenzyme Q10 plays a vital role in cellular energy production. It also increases the body's immune system via its antioxidant activity. The aim of this study was to evaluate the addition of coenzyme Q10 on physicochemical properties of pomegranate fruit juice. The variables were concentrations of coenzyme Q10 (10 or 20 mg in 300 ml) and storage temperature (25°C and 4°C) and the parameters were pH, titrable acidity, brix, viscosity, turbidity and sensory evaluation during three months of storage. By increasing time and temperature, pH was decreased and with increasing concentration of coenzyme Q10, pH was increased. Time and temperature had direct influence on acidity, and the concentration of coenzyme Q10 had the opposite effect on the acidity. With increasing storage time and concentration of coenzyme Q10, Brix, viscosity and turbidity levels were increased and with increasing time and concentration of coenzyme Q10, the Brix, viscosity and turbidity were increased. The addition of coenzyme Q10 in grape juice showed no negative effect on the physicochemical and sensory properties.

Effects of homogenization pressure and sequence on textural and microstructural properties of milk-based creamy dessert

Effects of homogenization sequence (before or after heating) and homogenization pressure (0, 50, or 150 bar) were studied on the certain textural properties of milk-based creamy dessert including hardness, surface tension and syneresis. Also, the microstructure of the treatments was analyzed using scanning electron microscopy (SEM). Homogenization at 50 bar after heating led to the highest hardness, whilst unhomogenized and homogenized treatments at 150 bar before heating resulted in the lowest hardness.  Using pressure of 50 and 150 bar after heating led to the highest and lowest surface tension, respectively. While the highest syneresis was observed when unhomogenized treatment applied, the lowest syneresis was obtained using primarily the treatments with homogenization after heating and then the treatments with homogenization before heating. Finally, good correlation was observed between the textural and rheological results and the micrographs of microstructure obtained from SEM metho

Healthful characteristics of pennyroyal essential oil

Pennyroyal, an aromatic herb, is considered by food and medicine industries. It grows in different countries and provides various technological and functional properties. Essential oils (especially ‘Pulegune’) are the effective materials of pennyroyal that causes anti-microbial, anti-oxidant and aromatic properties. These essential oils have significant effects on preventing growth of several species of pathogenic and spoilage bacteria. Furthermore, these oils maintain food quality by preventing the oxidation of fatty acids and increasing product shelf life. Therefore, it seems that pennyroyal is an appropriate alternative for synthetic antioxidants. On the other hand, it can be used in treatment from medicinal point of view. Overall, pennyroyal essential oils are a good, natural and economical alternative for food and medicine industries. The present article focuses on the healthful and technological characteristics of pennyroyal essential oils

Beer as a vehicle for probiotics

Background and Objective: 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. Conclusion: 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. Conflict of interest: The authors declare no conflict of interest

The effect of Saccharomyces strain and fermentation conditions on quality prameters of non-alcoholic beer

In this study, the effect of several species of fermenting yeast and fermentation conditions (periodic aeration and temperature) on quality parameters of non-alcoholic beer is assessed. Yeast starters with different inoculation percent were added separately into wort with determined gravity. Wort was fermented for 48 h in different temperatures under aerobic condition or periodic aeration (every 12 h). Growth rate, wort gravity and ethanol content were analyzed for 48 hours (12-h interval). Also, 6 trained panelists were asked for sensory evaluation of final product. The highest growth rate and the highest ethanol content were found in treatments with 4×107 cfu/ml inoculation fermented at 24˚C under periodic aeration and in those fermented under anaerobic conditions, respectively. The highest gravity was observed for treatments with 107 cfu/ml inoculation, periodic aeration and fermentation at 4˚C. The lowest growth rate and ethanol content were observed in treatments with 107 cfu/ml, fermented at 4˚C under anaerobic condition and those fermented under periodic aeration, respectively. In treatments with 4×107 cfu/ml inoculation, anaerobic condition and fermentation at 4˚C, the lowest gravity was observed. In addition, among yeasts, Saccharomyces cerevisiae and Saccharomyces rouxii showed the highest and the lowest growth rate, ethanol content and wort gravity, respectively. Additionally, treatments containing Saccharomyces cerevisiae resulted in non-alcoholic beer with more satisfactory flavor attributes

Determination of some nutritional value and organoleptic properties in fruity teas

Fruity teas are popular due to variety in sensory properties as well as their nutritional and therapeutical characteristics. Recently, the worldwide researches related to fruity teas have been considerably developed. In this work, effects of fruit type (apple, quince and pear) and brewing time (10 or 20 min) on some nutritional properties (Mg, Fe and Ca contents, sugars and protein percent) as well as on the sensory attributes of final products were investigated. No chemical preservative, flavoring gents and colorants were added for preparation of the samples. At the end of 10 min brewing, the highest extraction rates of Mg and protein, Fe and sugars, and Ca were observed for pear, apple, and quince, respectively. At the end of 20 min brewing, the greatest extraction rates of Mg and protein, sugars, and Ca were related to the pear, apple, and quince, respectively. Increasing the time of brewing up to 10 min although did not noticeably affect the extraction rate of nutrients from dried fruits (especially for protein content), significantly influence the sensory characteristics (flavor and color) of final products; so that those prepared by 20 min brewing had higher acceptability. Among the fruity teas produced by 20 min brewing, apple had the best sensory acceptability from flavor and color points of view. After that, pear tea from taste and quince tea from color standpoints were realized as the best samples

An overview of biotechnological production of propionic acid: From upstream to downstream processes

The increasing demand for propionic acid (PA) production and its wide applications in several industries, especially the food industry (as a preservative and satiety inducer), have led to studies on the low-cost biosynthesis of this acid. This paper gives an overview of the biotechnological aspects of PA production and introduces Propionibacterium as the most popular organism for PA production. Moreover, all process variables influencing the production yield, different simple and complex carbon sources, the metabolic pathway of production, engineered mutants with increased productivity, and modified tolerance against high concentrations of acid have been described. Furthermore, possible methods of extraction and analysis of this organic acid, several applied bioreactors, and different culture systems and substrates are introduced. It can be concluded that maximum biomass and PA production may be achieved using metabolically engineered microorganisms and analyzing the most significant factors influencing yield. To date, the maximum reported yield for PA production is 0.973 g\ub7g-1, obtained from Propionibacterium acidipropionici in a three-electrode amperometric culture system in medium containing 0.4 mM cobalt sepulchrate. In addition, the best promising substrate for PA bioproduction may be achieved using glycerol as a carbon source in an extractive continuous fermentation. Simultaneous production of PA and vitamin B12 is suggested, and finally, the limitations of and strategies for competitive microbial production with respect to chemical process from an economical point of view are proposed and presented. Finally, some future trends for bioproduction of PA are suggested