Evaluation of mono or mixed cultures of lactic acid bacteria in type II sourdough system.

The aim of this study was to evaluate the use of mono and mixed lactic acid bacteria (LAB) cultures to determine suitable LAB combinations for a type II sourdough system. In this context, previously isolated sourdough LAB strains with antimicrobial activity, which included Lactobacillus plantarum PFC22, Lactobacillus brevis PFC31, Pediococcus acidilactici PFC38, and Lactobacillus sanfranciscensis PFC80, were used as mono or mixed culture combinations in a fermentation system to produce type II sourdough, and subsequently in bread dough production. Compared to the monoculture fermentation of dough, the use of mixed cultures shortened the adaptation period by half. In addition, the use of mixed cultures ensured higher microbial viability, and enhanced the fruity flavor during bread dough production. It was determined that the combination of L. plantarum PFC22 + P. acidilactici PFC38 + L. sanfranciscensis PFC80 is a promising culture mixture that can be used in the production of type II sourdough systems, and that may also contribute to an increase in metabolic activity during bread production process.

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.