Food Preservatives from Plants

It has long been shown that phytochemicals protect plants against viruses, bacteria, fungi and herbivores, but only relatively recently we have learnt that they are also critical in protecting humans against diseases. A significant amount of medicinal plants is consumed by humans. As food‐related products, they additionally improve human health and general well‐being. This chapter deals with plant‐derived food preservatives. Particular attention has been paid to the following berry fruits: cranberry (Vaccinium macrocarpon), bilberry (Vaccinium myrtillus), black currant (Ribes nigrum), elderberry (Sambucus nigra), cornelian cherry (Cornus mas) and açaí (Euterpe oleracea), as well as the following herbs and spices: peppermint (Mentha piperita), basil (Ocimum basilicum), rosemary (Rosmarinus officinalis), thyme (Thymus vulgaris), nettle (Urtica dioica), cinnamon (Cinnamomum zeylanicum) bark, cloves (Syzygium aromaticum) and licorice (Glycyrrhiza glabra) as alternative sources of natural antimicrobial and antibiofilm agents with potential use in food industry. Moreover, we present an overview of the most recent information on the positive effect of bioactive compounds of these plants on human health. This chapter is a collection of essential and valuable information for food producers willing to use plant‐derived bioactive substances for ensuring the microbiological safety of products

Biofilms in Beverage Industry

Over the years, numerous studies have been conducted into the possible links between biofilms in beverage industry and health safety. Consumers trust that the soft drinks they buy are safe and their quality is guaranteed. This chapter provides an overview of available scientific knowledge and cites numerous studies on various aspects of biofilms in drinking water technology and soft drinks industry and their implications for health safety. Particular attention is given to Proteobacteria, including two different genera: Aeromonas, which represents Gammaproteobacteria, and Asaia, a member of Alphaproteobacteria

Novel permittivity test for determination of yeast surface charge and flocculation abilities

Yeast flocculation has been found to be important in many biotechnological processes. It has been suggested that flocculation is promoted by decreasing electrostatic repulsion between cells. In this study, we used an unconventional rapid technique—permittivity test—for determination of the flocculation properties and surface charge values of three industrial yeast strains with well-known flocculation characteristics: Saccharomyces cerevisiae NCYC 1017 (brewery, ale), S. pastorianus NCYC 680 (brewery, lager), and Debaryomyces occidentalis LOCK 0251 (unconventional amylolytic yeast). The measurements of permittivity were compared with the results from two classical methods for determination of surface charge: Alcian blue retention and Sephadex DEAE attachment. The permittivity values for particular strains correlated directly with the results of Alcian blue retention (r = 0.9). The results also confirmed a strong negative relationship between the capacitance of yeast suspensions and their flocculation abilities. The highest permittivity was noted for the ale strain NCYC 1017, with weak flocculation abilities, and the lowest for the flocculating lager yeast NCYC 680. This paper is the first to describe the possibility of using a rapid permittivity test to evaluate the surface charge of yeast cells and their flocculation abilities. This method is of practical value in various biotechnological industries where flocculation is applied as a major method of cell separation

Saponin-Based, Biological-Active Surfactants from Plants

Plants have the ability to synthesize almost unlimited number of substances. In many cases, these chemicals serve in plant defense mechanisms against microorganisms, insects, and herbivores. Generally, any part of the plant may contain the various active ingredients. Among the plant, active compounds are saponins, which are traditionally used as natural detergents. The name ‘saponin’ comes from the Latin word ‘sapo,’ which means ‘soap’ as saponins show the unique properties of foaming and emulsifying agents. Steroidal and triterpenoid saponins can be used in many industrial applications, from the preparation of steroid hormones in the pharmaceutical industry to utilization as food additives that exploit their non‐ionic surfactant properties. Saponins also exhibit different biological activities. This chapter has been prepared by participants of the Marie Sklodowska‐Curie Action—Research and Innovation Staff Exchange (RISE) in the framework of the proposal ‘ECOSAPONIN.’ Interactions between the participants, including chemists, physicists, technologists, microbiologists and botanists from four countries, will contribute to the development of collaborative ties and further promote research and development in the area of saponins in Europe and China. Although this chapter cannot provide a comprehensive account of the state of knowledge regarding plant saponins, we hope that it will help make saponins the focus of ongoing international cooperation

Biological Activity of Hydrophilic Extract of Chlorella vulgaris Grown on Post-Fermentation Leachate from a Biogas Plant Supplied with Stillage and Maize Silage

Algae are employed commonly in cosmetics, food and pharmaceuticals, as well as in feed production and biorefinery processes. In this study, post-fermentation leachate from a biogas plant which exploits stillage and maize silage was utilized as a culture medium forChlorella vulgaris. The content of polyphenols in hydrophilic extracts of the Chlorella vulgaris biomass was determined, and the extracts were evaluated for their antioxidant activity (DPPH assay), antibacterial activity (against Escherichia coli, Lactobacillus plantarum, Staphylococcus aureus, Staphylococcus epidermidis) and antifungal activity (against Aspergillus niger, Candida albicans, Saccharomyces cerevisiae). The use of the post-fermentation leachate was not found to affect the biological activity of the microalgae. The aqueous extract of Chlorella vulgaris biomass was also observed to exhibit activity against nematodes. The results of this study suggest that Chlorella vulgaris biomass cultured on post-fermentation leachate from a biogas plant can be successfully employed as a source of natural antioxidants, food supplements, feed, natural antibacterial and antifungal compounds, as well as in natural methods of plant protection

Enzymatic Conversion of Sugar Beet Pulp: A Comparison of Simultaneous Saccharification and Fermentation and Separate Hydrolysis and Fermentation for Lactic Acid Production

U radu je ispitana učinkovitost proizvodnje mliječne kiseline tehnikama odvojene hidrolize i fermentacije, te istodobne saharifikacije i fermentacije pulpe šećerne trske, nusprodukta proizvodnje šećera. Pulpa šećerne trske hidrolizirana je s pomoću pet komercijalnih enzima, te je proveden niz pokusa na tresilici s pet odabranih sojeva bakterija mliječno-kiselog vrenja. Postignuti su različiti prinosi ukupnih reducirajućih šećera, ovisno o aktivnosti enzima prilikom razgradnje glavnih sastojaka pulpe. Najveći prinos nakon hidrolize i najmanji talog dobiveni su primjenom mješavine komercijalnih enzima Viscozyme® i Ultraflo® Max u omjeru 1:1. U postupku odvojene hidrolize i fermentacije bakterije mliječno-kiselog vrenja iskoristile su samo dio ugljikohidrata oslobođenih enzimskom hidrolizom za rast. U postupku se istodobne saharifikacije i fermentacije pri maloj dozi enzima smanjila akumulacija šećera. Smanjila se i opasnost od kataboličke represije ugljikom. Dobiveni rezultati pokazuju da je istodobna saharifikacija i fermentacija bolja od tehnike odvojene hidrolize i fermentacije, između ostalog i zbog manjih troškova i većeg prinosa. Prinos mliječne kiseline dobiven istodobnom saharifikacijom i fermentacijom (oko 30 g/L) bio je 80-90 % veći nego onaj dobiven odvojenom hidrolizom i fermentacijom.This study compares the efficiency of lactic acid production by separate hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF) of sugar beet pulp, a byproduct of industrial sugar production. In experiments, sugar beet pulp was hydrolyzed using five commercial enzymes. A series of shake flask fermentations were conducted using five selected strains of lactic acid bacteria (LAB). The differences in the activities of the enzymes for degrading the principal sugar beet pulp components were reflected in the different yields of total reducing sugars. The highest yields after hydrolysis and the lowest quantities of insoluble residues were obtained using a mixture (1:1) of Viscozyme® and Ultraflo® Max. In the SHF process, only a portion of the soluble sugars released by the enzymes from the sugar beet pulp was assimilated by the LAB strains. In SSF, low enzyme loads led to reduction in the efficiency of sugar accumulation. The risk of carbon catabolic repression was reduced. Our results suggest that SSF has advantages over SHF, including lower processing costs and higher productivity. Lactic acid yield in SSF mode (approx. 30 g/L) was 80–90 % higher than that in SHF

Glycyrrhiza Genus: enlightening phytochemical components for pharmacological and health-promoting abilities

The Glycyrrhiza genus, generally well-known as licorice, is broadly used for food and medicinal purposes around the globe. The genus encompasses a rich pool of bioactive molecules including triterpene saponins (e.g., glycyrrhizin) and flavonoids (e.g., liquiritigenin, liquiritin). This genus is being increasingly exploited for its biological effects such as antioxidant, antibacterial, antifungal, anti-inflammatory, antiproliferative, and cytotoxic activities. The species Glycyrrhiza glabra L. and the compound glycyrrhizin (glycyrrhizic acid) have been studied immensely for their effect on humans. The efficacy of the compound has been reported to be significantly higher on viral hepatitis and immune deficiency syndrome. This review provides up-to-date data on the most widely investigated Glycyrrhiza species for food and medicinal purposes, with special emphasis on secondary metabolites’ composition and bioactive effects