Physicochemical and bioactive properties of edible methylcellulose films containing Rheum ribes L. extract.

Methylcellulose (MC) polymer was used to prepare the edible films. Then, the Rheum ribes L. ethanol extract (RE) was added to the films in order to act as a natural antimicrobial agent. All the methylcellulose films were characterized for bioactivity and the physicochemical analysis were carried out to define functional group interactions between the polymer and RE. The strongest antimicrobial effect was obtained with MC films enriched with 2% (w/w) RE against to Listeria monocytogenes with 20.3 ±â€¯2.5 mm zone diameter. In the presence of RE, the tensile strength of film decreased, whereas the extract concentration significantly increased. The elongation at break and the water vapor permeability (WVP) values of the films were found to have decreased significantly in parallel with the increase in RE content. Moreover, the increase in the concentration of RE caused an increment in the hydrophilic properties, especially contact angle values of the films.

Effects of temperature and packaging types on ergosterol and Howard mold count values of tomato paste during storage.

The objective of the present study was to investigate the effects of temperature and packaging on ergosterol and Howard mold count (HMC) changes of tomato paste during storage. The other purpose of this study was to determine whether the measurement of ergosterol stability in tomato paste can be useful for the assessment of microbiological quality of tomato paste as related to the storage temperature (4, 20, 28, or 37°C) and time. Ergosterol analysis was done by using high-performance liquid chromatography. Tomato paste samples were packaged in either aseptic bags or tin boxes and stored at 4, 20, 28, or 37°C for a period of 10 months. The detection limit of ergosterol was 0.1 mg/kg. Measurements showed that packaging and storage temperatures of 28 and 37°C have a considerable influence on ergosterol and HMC changes in the product. The poor precision of the "percentage of discarded fruits" and HMC methods has increased the importance of ergosterol for the microbiological quality evaluation of tomato and tomato products. This article reports the data from what we believe to be the first survey for the influence of storage temperature and packaging material on ergosterol and HMC changes of tomato paste during storage.

Patulin & ergosterol: new quality parameters together with aflatoxins in hazelnuts.

Hazelnuts of three different categories, mouldy, hidden mould and sound (undamaged), were investigated for their contents of aflatoxins (B1, B2, G1 and G2), patulin, and ergosterol. Samples were obtained from five hazelnut processing plants located in a major hazelnut producing area in the Black Sea region in Turkey. All aflatoxins, patulin and ergosterol were determined by high performance liquid chromatography (HPLC). Sound hazelnuts were contaminated with trace or zero amounts of aflatoxins, patulin and ergosterol, so they posed no risk for the consumer when national and/or international regulatory limits were considered. Mouldy and hidden mould hazelnuts were contaminated with high (246-510ppb; 141-422ppb) aflatoxin levels, respectively. Aflatoxin B1 content was significantly correlated with the patulin and ergosterol contents in mouldy and hidden mould hazelnuts. However, there was no significant correlation between patulin and ergosterol contents of mouldy and hidden mould hazelnuts.