Immobilization of Bacteriocins from Lactic Acid Bacteria and Possibilities for Application in Food Biopreservation

Bacteriocins are biologically active compounds produced by a large number of bacteria, including lactic acid bacteria (LAB), which exhibit antimicrobial activity against various saprophytic and pathogenic microorganisms. In recent decades, bacteriocins are increasingly becoming more important in different branches of the industry due to their broad antibacterial and antifungal spectrum - in the food industry for natural food preservation and expiry date extension; in the health sector for preparation of probiotic foods and beverages; in the clinical practice as alternatives of conventional antibiotics; in the agriculture as biocontrol agents of plant pathogens and alternatives of chemical pesticides for plant protection. The broad antimicrobial spectrum of bacteriocins has stimulated the research attention on their application mainly in the food industry as natural preservatives. Most scientific achievements concerning the application food biopreservation are related to bacteriocins produced by LAB. The lactic acid bacteria bacteriocins can be produced in the food substrate during its natural fermentation or can be added in the food products after obtaining by in vitro fermentations under optimal physical and chemical conditions. Moreover, the immobilization of LAB bacteriocins on different matrices of organic and inorganic origin has been proposed as an advanced approach in the natural food preservation for their specific antimicrobial activity, anti-biofilm properties and potential use as tools for pathogen detection

Optimized Entanglement Purification

We investigate novel protocols for entanglement purification of qubit Bell pairs. Employing genetic algorithms for the design of the purification circuit, we obtain shorter circuits achieving higher success rates and better final fidelities than what is currently available in the literature. We provide a software tool for analytical and numerical study of the generated purification circuits, under customizable error models. These new purification protocols pave the way to practical implementations of modular quantum computers and quantum repeaters. Our approach is particularly attentive to the effects of finite resources and imperfect local operations - phenomena neglected in the usual asymptotic approach to the problem. The choice of the building blocks permitted in the construction of the circuits is based on a thorough enumeration of the local Clifford operations that act as permutations on the basis of Bell states

Polyphenols as Suitable control for Obesity and Diabetes

Modern life is characterized by physical inactivity and poor food choices, which is often a prerequisite for unhealthy weight gain and overweight/obesity. These factors unlock the emergence of a number of diseases including diabetes, cardiovascular problems, different types of cancer, etc. The pursuit of scientists to seek strategies to prevent, relieve and cure the patient leads to the usage of natural compounds of potential beneficial effect. Polyphenols are a large group of naturally occurring secondary metabolites mainly found in plants and beverages. The presence of these secondary metabolites seems to decrease the manifestation of miscellaneous disease-causing symptoms. The purpose of this review is to synthesize information about polyphenols and their potential in controlling obesity and diabetes. Polyphenols are considered as health-beneficial sources and thus could be involved in novel strategies for preventing diabetes and obesity complications

Phytochemical constituents of pressurized liquid extract from Ziziphus jujubа Mill. (Rhamnaceae) fruits and in vitro inhibitory activity on α-glucosidase, pancreatic α-amylase and lipase

The phytochemical composition of extract from Ziziphus jujubа Mill (Rhamnaceae) fruits obtained by pressurized liquid extraction (PLE) was investigated in the current study. The phytochemical analysis showed the presence of triterpenes, flavonoids and phenolic acids. The fruit extract had a total phenolic content of 21 ±2.01 mg gallic acid equivalents per g of extract. (mg GAE/g extract), and total flavonoid content 2.48 ± 0.24 mg catechin equivalents per g dried extract (mg CE/g extract). This study evaluated the in vitro antioxidant activity of jujube extract and its inhibitory effects on α-glucosidase and pancreatic α-amylase and lipase. The obtained results proved inhibition of α-glucosidase with 70.94% and inhibition of α-amylase with 56.08%. Enzyme kinetic studies indicated that the inhibitors in the extract have the most potent inhibition of lipase compared to the other two enzymes with inhibitory constant Ki of 0.074 mg/cm3 . These results suggest the possible application of extract from Z. jujubа fruits obtained by PLE in the management of metabolic disorders as a whole. These are the first studies on this plant species cultivated in Bulgari

Probiotic Characteristics and Health Benefits of the Yogurt Bacterium <em>Lactobacillus delbrueckii</em> sp. <em>bulgaricus</em>

Yogurt is a good source of several micronutrients and has played an important role in human nutrition. Consumption of yogurt has been shown to promote health benefits due to the presence of live bacteria. A number of human studies have demonstrated that yogurt contains viable bacteria, and especially L. bulgaricus, improve the health of the host and thus qualifies as a bona fide probiotic in its own right. In this chapter, we review the literature covering attributes of the yogurt bacterium L. bulgaricus that confirm its probiotic bacterial characteristics

Volatile Aromatic Flavor Compounds in Yogurt: A Review

Lactic acid bacteria are of great importance in the production of yogurt worldwide, yet very little is still known about the mechanisms of aroma formation in foods subjected to lactic acid fermentation. However, advances in the Adolfsson development of instrument methods have made it possible to avoid some of the difficulties in extracting flavoring substances from the otherwise complex matrix of lactic acid products. In this chapter, we present recent developments related to the impact of yogurt starter cultures on the production of the aromatic components in yogurts. In addition, we examine and characterize the aromatic compounds based on the chemical structures and discuss modern analytical techniques for yogurt analysis. As described in this chapter, a large number of flavoring substances can be studied, isolated, and identified with the help of advanced instrument analysis such as synthetic fibers for solid-phase extraction (SPME) and gas chromatography combined with mass spectrometry (GC-MS). These techniques can help us reach a more advanced level of understanding of the importance of specific strains for obtaining the desired sensory qualities of fermented, lactic acid products. At a more advanced stage, these analyses could allow scientists to develop rapid methods for determining the quality and authenticity of lactic acid products based on the aromatic-metabolic profile of starter cultures in the final product

Design and Volatile Compound Profiling of Starter Cultures for Yogurt Preparation

Stable symbiotic starter cultures were created using selected strains of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus with antimicrobial activity against pathogens and necessary antibiotic sensitivity, growth kinetic parameters, and metabolic profiles. The volatile compound profiles of the obtained starter cultures were determined and their specificity was proven depending on the ratio of monocultures in each combination. The influence of the freeze-drying process on the starter cultures in relation to the production of aromatic components was investigated and it was demonstrated that this process had a significant effect on the content of the aroma-forming substances in the fermented milk. However, the influence of the pre-cooling process and crude fat content from 1.5 to 3.0% did not notably affect the levels of volatile compounds synthesized by the selected starter cultures. Comprehensive data for all volatile aromatic metabolites in the fermented milk were also obtained. These designed symbiotic starter cultures can be used to produce traditional Bulgarian yogurt with increased functional and probiotic properties