Synthetic preservatives are widely used by the food industry to control the growth of spoilage and pathogenic microorganisms and to inhibit the process of lipid oxidation extending the shelf-life, quality and safety of food products. However, consumer's preference for natural food additives and concern regarding the safety of synthetic preservatives prompted the food industry to look for natural alternatives. Natural antimicrobials, including plant extracts and their essential oils, enzymes, peptides, bacteriocins, bacteriophages, and fermented ingredients have all been shown to have the potential for use as alternatives to chemical antimicrobials. Some spices, herbs and other plant extracts were also reported to be strong antioxidants. The antimicrobial/antioxidant activities of some plant extracts and/or their essential oils are mainly due to the presence of some major bioactive compounds, including phenolic acids, terpenes, aldehydes, and flavonoids. The proposed mechanisms of action of these natural preservatives are reported. An overview of the research done on the direct incorporation of natural preservatives agents into meat and poultry products as well as fruit and vegetables to extend their shelf-life is presented. The development of edible packaging materials containing natural preservatives is growing and their applications in selected food products are also presented in this review.

Commercial lipases, from porcine pancreas (PPL), Candida rugosa (CRL), and Thermomyces lanuginosus (Lipozyme TL IM), were investigated in terms of their efficiency for the hydrolysis of safflower oil (SO) for the liberation of free linoleic acid (LA), used as a flavor precursor. Although PPL, under the optimized conditions, showed a high degree of hydrolysis (91.6%), its low tolerance towards higher substrate concentrations could limit its use for SO hydrolysis. In comparison to the other investigated lipases, Lipozyme TL IM required higher amount of enzyme and an additional 3 h of reaction time to achieve its maximum degree of SO hydrolysis (90.2%). On the basis of the experimental findings, CRL was selected as the most appropriate biocatalyst, with 84.1% degree of hydrolysis. The chromatographic analyses showed that the CRL-hydrolyzed SO is composed mainly of free LA.

Impact of rheological properties of substrate on anaerobic digestion and digestate dewaterability: New insights through rheological and physico-chemical interaction, Water Research,

The objective of the research was the synthesis of linoleic acid hydroperoxides (HPOD) and their recovery, using selected sources of linoleic acid (LA) as substrate. This is part of on‐going work aimed at the development of an economically viable biotechnological process for the production of natural flavors. The investigated sources included pure (100 %) LA and commercial (67 %) LA as well as safflower oil (SO) and its hydrolyzed product. A model describing commercial LA oxidation by lipoxygenase, based on Michaelis–Menten kinetics, was developed. The conversion of pure LA and commercial LA resulted in insignificant differences in HPOD yield of 69.7 and 68.9 %, respectively. However, there was a significant difference in the HPOD yield, obtained from the SO (2.0 %) and that from the hydrolyzed SO (58.0 %) in comparison to that from pure LA (69.7 %). The ratios of the different 9‐ and 13‐HPOD isomers were insignificantly different for the sources containing free LA, with 13‐(9Z,11E)‐HPOD was the highest relative percentage. Using optimized conditions, HPOD yields were 85.9 and 74.0 % for the commercial LA and the hydrolyzed SO, respectively. Based on experimental findings, commercial (67 %) LA was selected as the most appropriate alternative to pure LA for the production of HPOD. An efficient extraction procedure for the recovery of HPOD was also developed.

The presence of selected dehydrogenases, including alcohol dehydrogenase (ADH-YL) and aldehyde dehydrogenase (ALDH-YL), in Yarrowia lipolytica JMY 861, and their potential role in flavor synthesis were investigated. The experimental findings showed that using reduced form of nicotinamide adenine dinucleotide (NADH) as cofactor, the ADH-YL activity in vitro was 6-fold higher than that with reduced form of nicotinamide adenine dinucleotide phosphate (NADPH); however, under the experimental conditions used in this study, an ALDH-YL activity was not detected. The in situ hexanal reduction reaction was found to be instantaneous; however, when the yeast cells suspension was diluted 150 times, the initial relative hexanal concentration was increased by 84.1%. The chromatographic analyses indicated the conversion, in situ, of linoleic acid hydroperoxides (HPODs) into volatile C-compounds after 60 min of HPODs addition to the yeast cells suspension.