Volume 19 (2015): Issue 2 (December 2015)

Pumpkin processing into puree, juice, candied fruit and pumpkin seed oil results in large amount of by-products. Pumpkins are rich in carotenes, vitamins, minerals, pectin and dietary fibre. The aim of the current study was to evaluate effect of pumpkin pomace and pumpkin residue powder on wheat bread quality. The total content of carotenes was analyzed by spectrophotometric method. The initial increase of pumpkin residue addition indicated increase in loaf volume, which started to decrease at higher amounts. Sensory evaluation (appearance; surface, crust; porosity; texture, crumb; taste, and flavour) of wheat bread with pumpkin revealed very high consumer acceptance except sample with 50% pomace addition. Total carotene content and colour b* value in wheat bread increased by adding pumpkin by-products. It is recommended to add 5% and 10% of pumpkin powder and no more than 30% of pumpkin pomace (calculated per 100 kg of flour) to dough for production of wheat bread with pumpkin by-product additions.

This paper presents a novel approach to the selection of plants to restore the lost aroma based on the oxidation processes. The predisposition of raw material components to lipid oxidation is the basis of selection criteria. It was determined that the content of unsaturated fatty acids in the lipid extract of watermelon, pumpkin, cucumbers is 30-40%, the ratio of linoleic and linolenic acids in fruit is different. The formation of diene conjugates and hydroperoxides, malondialdehyde after various processing treatment methods is shown. The efficiency of aroma restoration depends on the number of formed 9-, 13- hydroperoxides that serve as a substrate for aroma-forming enzymes. The antioxidant capacity and the oxidation-reduction potential of fresh fruits and fruits after cooking have been analyzed. These characteristics determine the fruit ability to repeated formation of aromatic components. It has been ascertained that gourds have sufficient potential to restore aroma by exogenous lipoxygenases.

With the rapidly development of fermented milk product, it is significant for enhancing the performance of starter culture. This paper not only investigated the influence of anti-freeze factors and freeze-drying protective agents on viable count, freeze-drying survival rate and yield of Lactobacillus bulgaricus (LB) and Streptococcus thermophilus (ST), but also optimized the bacteria proportion of freeze-dried starter culture for yogurt by full factorial experimental design. The results showed as following: the freeze-drying protective agents or anti-freeze factors could enhanced survival rate of LB and ST; the freeze-dried LB and ST powders containing both of anti-freeze factors and freeze-drying protective agents had higher viable count and freeze-drying survival rate that were 84.7% and 79.7% respectively; In terms of fermentation performance, the best group of freeze-dried starter for yogurt was the compound of LB3 and ST2.

The results of studies in the field of beverage functionality using walnut are presented. The main components such as celery, Jerusalem artichokes, carrots, pumpkin and rhubarb, as a dietary supplement - extracts from walnut of milk-maturity stage are offered for creating blends. The basic physical and chemical properties of fruit and vegetable raw materials and semi-finished products created on the base of them have been studied, and their nutritional and biological value has been proved. Rational technologies of fruit and vegetable blends with nut additives have been identified. Their biological value has been confirmed. Drinks are recommended for use in the daily diet of human beings to satisfy thirst and enrich the body by biologically valuable components.

In this paper, yoghurts from ultrafiltered concentrated whole milk with a volume reduction ratio 0, 2 and 3 with three different probiotic yoghurt starters were obtained. Their physiological, microbiological and rheological properties were examined. The concentrated probiotic yoghurts had high concentration of viable cells of the probiotic strain Lactobacillus delbrueckii ssp. bulgaricus (over 10¹⁰cfu/cm³). For the preparation of concentrated probiotic yoghurts the most appropriate volume reduction ratio was 2. The probiotic yoghurts with starters MZ₂ and 1CM had the best structure. The concentrated probiotic yoghurts with all starters are functional foods.

Oxidation was related to the pathogenesis of human diseases. Adequate intake of antioxidant activity of food can reduce the levels of free radicals, prevent lipid peroxidation, and help the body against diseases. In the paper, casein from goat milk was hydrolyzed by five commercial proteases, namely, Alcalase, flavourzyme, papain, proteinase K and trypsin. The antioxidant activities of casein hydrolysates were assessed by evaluating hydrolysis degree, DPPH radical-scavenging activity, metal-chelating activity and superoxide radical scavenging activity. The results showed as follows: the DH of proteinase K, Alcalase, and trypsin were higher significantly than those of papain and flavourzyme. The Fe²⁺-chelation activity and superoxide radical scavenging activity of casein hydrolysates from goat milk by Alcalase was higher than the others, the DPPH scavenging activities of casein hydrolysates by Alcalase and papain was higher than the others and the DPPH scavenging activities by Alcalase and papain had no significant diffierence (p<0.05), so the optimal proteinase for hydrolysis casein from goat milk to produce antioxidant peptide was Alcalase.

This paper investigates the antimicrobial action of the extracts and essential oil of wildgrowing Tanacetum vulgare L on: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Bacilus subtilis, using the diffusion disc method. The essential oils but also the ethanolic extracts tested exhibited moderate action on Staphilococcus aureus and Bacillus subtilis and low action on E. coli and Pseudomonas aeruginosa. The moderate antimicrobial activity is related to the amount of some chemical components of the essential oil of T. vulgare flos. Thus, this paper presents also the quantitative and qualitative analysis of the essential oils of T. vulgare harvested from two different habitats. The essential oils obtained by steam-distillation were analysed by gas-cromatography coupled with mass spectrometry (GC-MS).