Spirulina platensis is a cyanobacterium (blue-green algae) that grows in alkaline waters. In food industry, Spirulina’s phycocyanin is used as a natural colorant and stabilizer. The influence of three different concentrations of Spirulina platensis (0.5%, 1% and 1.5%) on physicochemical, textural, antioxidant and sensory parameters of ice cream was studied. It was found that with increasing spirulina concentration, the overrun increases from 30.6% (IC–0) to 48.3% (IC–3). The analysis of texture profile (hardness, adhesiveness, cohesiveness, gumminess) of samples showed a statistically significant difference (p<0.05) between reported values for control sample (IC–0) and the samples with spirulina. Ice cream samples supplemented with spirulina differed with significant increase (p<0.05) in antioxidant activity from 2.8±2.2 mM TE/100 g DW (control sample) to 112.9±4.1 mM TE/100 g DW (IC–3). The addition of Spirulina platensis in ice cream mixture improves its quality and antioxidant properties.

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Introduction. The aim of the present study is to obtain enriched in vitamin C yoghurt by direct extraction of rosehip fruit in cow's milk. Materials and methods. Cow's milk from cows grown in the Yambol region was used to carry out extraction of rosehip fruits (R. Caniana). The content of vitamin C in the yoghurt obtained was determined by the Officials methods of analysis, 2000, as well as the total number of lactic acid microorganisms contained according to EN ISO 6610:2006; ISO 7889. Results and discussion. The active acidity of the yoghurt was monitored during both periods of preparation and storage. At the end of the storage period (14 days), the active acidity reached pH 4,2-4,3. For the same period, the vitamin C content was the highest in sample 2 and varied from 13,65-13,12 mg.g-2. The dry matter content in the yoghurt obtained was determined. Higher values of dry matter were observed in samples 2 and 3, with values varying from 12,60% to 13,4%. The higher values of the dry matter content in the product were due to the pectin type substances extracted during the extraction process. The pectin substances extracted into the milk stabilized the coagulum, improved the taste and the nutritious value of the yoghurt obtained. The total number of viable bacteria in the yoghurts obtained was determined and they were found to increase during the storage period. The highest total number of viable lactic acid bacteria was observed for Sample 2-3,6.10 8 CFU.g-2 which is about 10 times more than these in Sample 1 (reference). Conclusions. The yoghurt obtained by direct extraction of dry rosehip fruits (Rosa canina L) into cow's milk at hydromodule 1:15 possessed the properties of functional food because of the content of vitamin C in it which varied from 13,65 to 13,12 mg.g-2. The preparation of vitamin C enriched yoghurt can be used to produce new lactic acid products providing health benefits.

This paper presents a research over possibilities to evaluate a cut surface of white brined cheese by images analysis. Samples from seven trademarks of Bulgarian white cheese in brine are evaluated by experts and their cut surfaces are captured with digital camera. A Java application for color images processing in HSI color space is developed. The application executes multilevel thresholding and produces grayscale images with four colors – white, black, light gray and dark gray. The images of all tested cheese samples are processed with this application and there are calculated ratios of pixels with the same color to all pixels in the processed images (Kdiv for white, black, light gray and dark gray colors). The cut surfaces of cheese samples are evaluated by experts and it is performed a correlation analysis between experts’ estimation and the coefficients Kdiv. The results show that there are a significant correlation between experts’ estimation and the pixels with dark gray color (their coefficient Kdiv) in the processed images.

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