Variations in the Composition, Antioxidant and Antimicrobial Activities of Cystoseira compressa during Seasonal Growth.

The underexplored biodiversity of seaweeds has recently drawn great attention from researchers to find the bioactive compounds that might contribute to the growth of the blue economy. In this study, we aimed to explore the effect of seasonal growth (from May to September) on the in vitro antioxidant (FRAP, DPPH, and ORAC) and antimicrobial effects (MIC and MBC) of Cystoseira compressa collected in the Central Adriatic Sea. Algal compounds were analyzed by UPLC-PDA-ESI-QTOF, and TPC and TTC were determined. Fatty acids, among which oleic acid, palmitoleic acid, and palmitic acid were the dominant compounds in samples. The highest TPC, TTC and FRAP were obtained for June extract, 83.4 ± 4.0 mg GAE/g, 8.8 ± 0.8 mg CE/g and 2.7 ± 0.1 mM TE, respectively. The highest ORAC value of 72.1 ± 1.2 µM TE was obtained for the August samples, and all samples showed extremely high free radical scavenging activity and DPPH inhibition (>80%). The MIC and MBC results showed the best antibacterial activity for the June, July and August samples, when sea temperature was the highest, against Listeria monocytogenes, Staphylococcus aureus, and Salmonella enteritidis. The results show C. compressa as a potential species for the industrial production of nutraceuticals or functional food ingredients.

Sustainable sources for antioxidant and antimicrobial compounds used in meat and seafood products.

The contribution of food in promotion of health has become of most importance. The challenges that lie before the global food supply chain, such as climate changes, food contamination, and antimicrobial resistance may compromise food safety at international scale. Compounds with strong antimicrobial and antioxidant activity can be extracted from different natural and sustainable sources and may contribute to extend the shelf life of meat and seafood products, enhance food safety and enrich foods with additional biologically active and functional ingredients. This chapter describes the use of bioprotective cultures, essential oils, plant extracts, seaweed extracts and grape pomace compounds in production of value-added meat and seafood products with improved shelf life and safety, following the requests from the market and consumers.

Modeling of yeast thermal resistance and optimization of the pasteurization treatment applied to soft drinks.

Yeast are usually responsible for spoilage of soft drinks and fruit beverages, because of the particular characteristics of these products (low pH, high C/N ratio). The microbial stability is guaranteed by thermal treatments. However, excessive heat treatments can affect food sensorial quality. In this work the thermal resistance of different yeasts strains (seven belonging to the species Saccharomyces cerevisiae and six belonging to the species Kluyveromyces marxianus, Zygosaccharomyces bisporus, Z. mellis, Z. rouxii, Schizosaccharomyces pombe and Saccharomycodes ludwigii) was assessed in a model system. The results showed non-linear death curves and a high variability also within the same species. The most resistant strain, belonging to the species S. cerevisiae, was chosen for further experiments in orange juice based industrial beverages: first, death curves were performed; then, the probability of beverage spoilage in relation to process parameters (initial inoculum, temperature, treatment time) was evaluated using a logistic regression model. Finally, a cross-validation was performed to investigate the predictive capability of the fitted model. Pasteurization in the soft drink industry is commonly applied according to parameters defined several decades ago, which does not consider the successive findings concerning microbial physiology and stress response, the process improvement and the more recent tools provided by predictive microbiology. In this perspective, this study can fill a gap in the literature on this subject, going to be a basis for optimizing thermal processes. In fact, the data obtained indicated an interesting possibility for food industry to better modulated (and even reduce) thermal treatments, with the aim to guarantee microbial stability while reducing thermal damage and energy costs.

Matricaria genus as a source of antimicrobial agents: From farm to pharmacy and food applications.

Matricaria is a widespread genus of flowering plants of the family Asteraceae that grow in temperate regions of Europe, Asia, America and Africa. Some of the species are also naturalized in Australia. Some species of this genus such as Chamomiles are recognized medicinal plants and cultivated in several countries for commercial purposes: to obtain its blue essence, as herbal tea, and for pharmaceutical or cosmeceutical uses. The phytochemical composition of Matricaria spp. includes volatile terpenoids (e.g., α-bisabolol, bisabolol oxide A and B, ß-trans-farnesene and chamazulene), sesquiterpene lactones such as matricin, and phenolic compounds (flavonoids, coumarins and phenolic acids). Their essential oil is obtained from the fresh or dried inflorescences by steam distillation, and additionally cohobation of the remaining water. The volatile composition of the essential oil, especially the content of the valuable components α-bisabolol and chamazulene, depends on the plant part, origin and quality of the source, genetic, and environmental factors. Moreover, other parameters, such as season of harvest and methods of extraction, can affect the extraction yield of the essential oils/extracts, their composition and, therefore, their bioactivity. Due to the importance of this genus and particularly M. recutita (M. chamomilla), this review focus on its cultivation, factor affecting essential oils' composition and their role in traditional medicine, as antibacterial agents and finally as food preservatives.

Combined effects of high pressure homogenization treatment and citral on microbiological quality of apricot juice.

High pressure homogenization (HPH) technique is able to significantly reduce spoilage microbiota in fruit juice. On the other hand, aroma compounds and essential oils can have a key role in the microbial stability of these products. For this reason, the aim of this work was to evaluate the combined effects of an aroma compound (citral, used at a concentration of 50 mg/l) and HPH treatments (performed at 100 MPa for 1-8 successive passes) on the inactivation dynamics of Saccharomyces cerevisiae SPA strain inoculated in apricot juices at level of about 4.5 log CFU/ml. Moreover, growth of surviving yeast cells was measured during the storage of the treated juice at 10°C and pH, water activity, viscosity and volatile molecule profile of apricot juice were studied. Since citral had been diluted in ethanol before the addition to juice, also samples with only ethanol added at the same volume used to dissolve citral were considered. The results showed that yeast cell viability decreased with the increases of passes at 100 MPa and the relationship between yeast cell loads and number of passes at 100 MPa followed a linear trend. In addition, the effect of HPH treatment can be notably potentiated throughout the presence of citral and ethanol, increasing the time necessary to reach a spoilage threshold during storage. The volatile profiles of the juices added with citral showed a substitution by yeast metabolism of this aldehyde with molecule characterized by a lower antimicrobial activity such as alcohols. The HPH treatments had also a significant effect on pH and viscosity of apricot juices while did not affect a(w).

Modeling of combined effects of citral, linalool and beta-pinene used against Saccharomyces cerevisiae in citrus-based beverages subjected to a mild heat treatment.

The aim of this work was to evaluate the antimicrobial activity of three terpenes (citral, linalool and beta-pinene), in combination with a mild heat treatment (55 degrees C, 15 min). The study has been carried out on an orange based soft drink inoculated using a wild strain of Saccharomyces cerevisiae. The results, expressed as growth/no-growth data, were analyzed with the logistic regression. A model comprising only of significant individual parameters (p < or = 0.05) and describing the relationships between terpene concentrations and the probability of having stable beverages was obtained. When citral and beta-pinene were combined, the citral concentration required to achieve a 50% probability of having stable bottles (P=0.5) dropped from 100.9 microL/L in the absence of beta-pinene to 49.3 microL/L in the presence of 20 microL/L of beta-pinene. The mixture of citral and linalool was less effective, in fact, the same probability (P=0.5) was obtained combining 60 microL/L of linalool with 35.1 microL/L of citral. The addition of 20 microL/L of linalool and beta-pinene reinforced citral bioactivity and the concentration of citral needed to reach P=0.5 fell from 100.9 microL/L in the presence of citral alone to 42.0 microL/L. The presence of both linalool and beta-pinene at a concentration of 40 or 60 microL/L in the absence of citral led to a lower spoilage probability (P=0.58 and P=0.93, respectively). It can be concluded that the antimicrobial potential of the three terpenes alone can be strengthened combining appropriate concentrations of each of them. This study confirmed also the potentiating effect of a mild temperature treatment on the antimicrobial efficacy of the molecules. Neither the thermal treatment alone nor the presence of the terpenes at their maximum concentrations (without thermal treatment) were able to guarantee the microbial stability of the beverages.